Tái Tạo Thể Tích Khuôn Mặt Bằng Filler – Kyle K. Seo (2021)

85
© Springer Nature Singapore Pte Ltd. 2021
K. K. Seo, Facial Volumization with Fillers,
Hyaluronic Acid (HA) Filler
Injection Procedure
3.1
Preparation Prior
to the Injection
3.1.1
Preparation of Tray
Tray Setup: Filler, needle, cannula, gauze, beta-
dine balls, chlorohexidine  gauze, boric acid
gauze, Tegaderm® transparent film.
Prepare two sterile (or disposable) trays, one
containing HA filler(s) only and the other con-
taining the remaining instruments, including the
needle, cannula, gauze, betadine balls, chloro-
hexidine gauze, boric acid gauze, and Tegaderm®
film (Fig. 3.1). The purpose of such segregation
is to prevent the potential contamination of rem-
nants of HA fillers that have been prepared for
injection, given that the precise amount of HA
filler to be used in a procedure cannot be calcu-
lated in advance. Use only sterile forceps to
transfer the HA filler from one tray to the other.
3.1.2
Dispensing
It can be helpful to divide the 1-mL syringe of
HA filler into volumes of 0.2, 0.3, and 0.5 mL in
preparation for cases where a full 1-mL syringe
is unlikely to be used (Fig. 3.1). The HA filler is
dispensed by transferring each subdivision into
an empty 1-mL syringe (Beckton Dickinson®)
using a three-way. As a general rule, filler dis-
pensed into smaller volumes should be con-
sumed within the same day to prevent
contamination.
3.1.3
Dilution of HA Filler
HA fillers have a propensity to draw water from
surrounding tissues over time and expand. Due to
this nature, the HA filler may demonstrate an
incremental increase in volume 2–4  weeks
postinjection vis-a-vis the initial injection vol-
ume. Monophasic HA fillers tend to show a
higher degree of water absorption compared with
biphasic HA fillers. As such, dilution is advised
when using monophasic HA fillers to limit unfa-
vorable swelling due to their water retention
capacity. The ideal dilution ratio between the
monophasic HA filler and the diluent is approxi-
mately 1:0.6. The diluent is prepared by admix-
ing a 0.5 mL saline solution with 0.1 mL lidocaine
2%. Syringes respectively containing the  HA
filler and the diluent are connected onto a three-­
way or a “transfer,” and the liquid is pumped
back and forth between the two syringes in a pis-
ton movement at least 20 times to ensure thor-
ough mixture (Fig. 3.2).
3.1.4
Disinfection
Whilst rare, acute bacterial infection following
HA filler injection can occur. However, to an even
3

86
lesser extent, there can also be incidences of
delayed inflammatory nodules due to the introduc-
tion of nonpathogenic resident skin flora into the
tissue, or formation of biofilms from nonspecific
mycobacteria occuring months after the treatment.
To avoid such adverse events, meticulous prepara-
tion and disinfection of the skin are required prior
to the injection of HA filler. As the first step, make-
up should be thoroughly removed from the
patient’s face, after which the skin is to be disin-
fected with betadine balls. Further cleansing is
performed with chlorohexidine and boric acid
balls. Note, however, that disinfecting the skin
does not necessarily guarantee full sterility. Hence,
vigilance is still required to ensure that the needle
or cannula does not come into contact with the
skin ­surface during the procedure. This risk is
notably higher when injecting with a long cannula,
as the instrument may inadvertently brush against
the skin during its entry and advancement, becom-
ing contaminated with any remaining resident bac-
teria on the skin. Placing a Tegaderm® transparent
film dressing, over the cannula entry point helps to
avoid such risk (Fig.  3.3). Where the procedure
involves making multiple punctures on the skin or
multiple back-and-forth strokes of the needle or
cannula, the instrument should be replaced as fre-
quently as possible during the procedure to mini-
mize the risk of contamination.
3.1.5
Anesthesia
3.1.5.1 Topical Anesthetic Cream
Local anesthetic cream containing lidocaine
applied for more than 20–30 min can help miti-
gate pain caused by the needle pucture during
the procedure. In patients who are sensitive to
pain, it may be beneficial to keep the numbing
cream on the skin for around 1  hour. A local
anesthetic cream applied around the cannula
entry point 20–30  mins in advance can be
instrumental in reducing pain during the punc-
ture of the entry point with a needle.
Fig. 3.1  Preparation of
tray
Fig. 3.2  Dilution of HA filler (Bellotero® Volume) with
normal saline
3  Hyaluronic Acid (HA) Filler Injection Procedure

87
3.1.5.2 Nerve Block
Nerve blocks allow the HA filler to be injected
almost painlessly by blocking the specific sen-
sory nerve(s) supplying the target area. The use
of nerve blocks may be helpful in minimizing
pain during the augmentation of the forehead,
lower pretarsal roll, lips, or the chin. However,
given that most fillers in use today come pre-
mixed with lidocaine if not reconstituted in the
office with local anesthesia, a nerve block is not
always a prerequisite to an HA filler procedure.
One possible exception is forehead augmenta-
tion, which can be extremely painful in the
absence of nerve blocks as the procedure involves
the scraping of the periosteum with a cannula as
the HA filler is delivered. The target nerves and
the injection points are summarized in Fig. 3.4
[1]. As shown in Table 3.1, the supraorbital nerve
and the supratrochlear nerve are targeted for fore-
head augmentation, infraorbital nerve blocked
for pretarsal roll augmentation, mental nerve
block used for chin augmentation, and infraor-
bital and mental nerves targeted for lip augmen-
tation and hydrolifting around mouth and chin.
Anesthesia of the forehead is provided by
supraorbital and supratrochlear nerve blocks,
which are performed as follows. For the supraor-
bital nerve block, palpate the supraorbital fora-
men (or notch) located at the medial aspect of
the supraorbital rim from which the supraorbital
nerve emerges, and inject 1 mL of 2% lidocaine
into the frontal bone lying immediately above
the said notch or foramen. Where the supraor-
bital foramen or notch cannot be palpated by
hand, inject the local anesthetic instead into a
point 20–25  mm lateral to the median sagittal
plane (Fig. 3.4a, b) [1]. The supratrochlear nerve
may on occasion arise out of the supraorbital
foramen or notch in tandem with the supraorbital
nerve. However, to provide for cases where the
supratrochlear nerve makes a separate emer-
gence, it is best to inject 1 mL lidocaine addi-
tionally 1 cm medial to the supraorbital notch, as
the supratrochlear nerve usually runs approxi-
mately 5–10  mm medial to the said notch
(Fig. 3.4c) [1].
Meanwhile, an infraorbital nerve block for lip
augmentation can be administered either from
inside or outside the oral cavity. In the extraoral
approach, 2% lidocaine 1  mL is injected 1  cm
inferior to the lower orbital rim along the mid
pupillary line to block the infraorbital nerve aris-
ing from the infraorbital foramen. In the intraoral
approach, the needle is inserted superiorly into
the mucosa above the maxillary second premolar
teeth (Fig. 3.4d) [2]. A mental nerve block for lip
fillers can also be performed either extraorally or
intraorally. In the extraoral approach, 1  mL of
lidocaine is injected 1 cm superior to the lower
margin of the mandible along the mid pupillary
line to block the mental nerve exiting from the
mental foramen. Alternatively, in the intraoral
approach, the injection is made inferoposterior to
the lower second premolar teeth Fig. 3.4e) [2].
Fig. 3.3  3 M Tegaderm® transparent film dressing over
the cannula entry point
3.1  Preparation Prior to the Injection

88
3.1.5.3 Anesthetic Injection
of the Cannula Entry Point
When volumizing the nose, lips, forehead, and
ears, etc. with HA filler, it is advisable to inject a
local anesthetic containing approximately 0.05 mL
of 2% dental lidocaine with epinephrine 1:100,000
at the cannula entry point 2–3 min prior to the pro-
cedure, as it helps to reduce bleeding while punc-
turing the entry point with a needle. The relevant
cannula entry points for each facial region are dis-
cussed in the respective sections.
3.1.5.4 Intravenous Anesthesia/
Sedation
Intravenous anesthesia or sedation may be under-
taken in patients with exceptionally low pain
threshold or fear of needles. Propofol (10 mg/mL)
is most commonly used for inducing sedation,
with an initial loading dose of 7–10  mL (70–
100 mg) followed by a maintenance infusion of
4–12 mg/kg/h or approximately 50–70 mL/h [3].
When propofol is administered in intermittent
bolus doses, 3–4 mL is injected every 3–5 min.
Supraorbital
nerve
Supratrochlear
nerve
intraorbital
nerve
Mental
nerve
a
Fig. 3.4  Target nerves for the nerve block during the
filler injection. (a) Target nerves and injection points of
the nerve block. (b) The supraorbital nerve block. (c) The
supratrochlear nerve block. (d) The intraoral approach of
the infraorbital nerve block. (e) The intraoral approach of
the mental nerve block
3  Hyaluronic Acid (HA) Filler Injection Procedure

89
The use of intravenous anesthesia can be benefi-
cial in procedures such as forehead augmentation,
as it obviates the need to perform nerve blocks and
helps to avoid the superfluous creation of volume
by the local anesthetic agent. The corresponding
drawback, however, is that the patient is typically
semi-awake upon recovery and is therefore not in
the best condition to adequately assess the post-
treatment results.
3.1.5.5 Distraction Method
According to the gate theory of pain, divergence
prevents effective transmission of the pain signals
by jamming up the nerve pathway with other stim-
uli. This explains why nurses tend to tap the
patient’s buttocks just before administering an
intramuscular injection. Likewise, tapping the
patient’s face with a finger or having the patient or
an assistant hold a vibration tool against the
patient’s face to distract the patient’s attention dur-
ing HA filler injection can be a useful way to allevi-
ate pain. Similarly, engaging the patient in constant
conversation during the procedure can help to draw
the patient’s mind away from the immediate pain.
b
c
d
e
Fig. 3.4  (continued)
Table 3.1  Target nerves of the nerve block depending on
the indications of filler injection
Indication
Target nerves
Forehead augmentation
Supraorbital nerve and
supratrochlear nerve
Pretarsal roll
augmentation
Infraorbital nerve
Lip augmentation
Infraorbital nerve and
mental nerve
Chin augmentation
Mental nerve
Hydrolifting around
mouth and chin
Infraorbital nerve and
mental nerve
3.1  Preparation Prior to the Injection

90
3.2
Injection Method
3.2.1
Needle vs. Cannula
Injectable fillers are still commonly referred to as
“dermal fillers” because they had originally been
developed for treating wrinkles in areas of reduced
skin elasticity. Where fillers were used primarily
for wrinkle treatment, needles had traditionally
been the instrument of choice for delivering the
filler through the stiff, rigid tissues of the dermis.
However, with the evolution in the use of inject-
able fillers for facial volume enhancement, deep
plane injection below the dermis has become the
norm. When injecting the deep planes though, the
use of needles carries a higher risk of traumatiz-
ing the deep-lying vessels not immediately visible
from the skin surface, resulting in hematoma for-
mation. Also, with the growing awareness over
the devastating consequences of inadvertent intra-
vascular injection of HA filler such as skin necro-
sis and blindness, the use of cannulas is
increasingly recommended over needles for facial
volumization treatments [4].
The decision whether to inject with a needle
or cannula is one that should essentially rest with
the injecting practitioner, as the best aesthetic
outcomes are achieved by a practitioner leverag-
ing his mastery of his most preferred technique.
That said, there are certain salient advantages of
using a cannula over a needle, as elaborated
below. One major advantage of using a cannula
over a needle lies in its significantly lower risk of
penetrating a vessel, which helps to prevent
bruising from unnecessary vascular damage and
avoid skin necrosis and visual loss from intravas-
cular occlusion. Accordingly, cannulas represent
a much safer option when injecting into areas that
are highly prone to risk of blindness such as the
glabella, nose, and nasolabial folds. Incidentally,
the use of a cannula may also provide the physi-
cian with better protection in the event of a
­litigation involving complications from intravas-
cular filler injection.
Despite their relative inability to pierce through
the vessel, it must be noted that using a cannula
does not entirely preclude the possibility of a vas-
cular complication. A cannula may be capable of
Diameter
Length
Diameter
Length
Diameter
Length
Diameter
Length
Diameter
Length
21G(∅0.8)
22G(∅0.7)
23G(∅0.6)
24G(∅0.56)
70mm
50mm
25G(∅0.5)
70mm
50mm
40mm
27G(∅0.41)
30mm
50mm
40mm
30G(∅0.31)
30mm
25mm
50mm
50mm
50mm
30mm
70mm
Diameter
Length
Diameter
Length
Fig. 3.5  Cannulas used for facial volumization come in a wide variety of sizes, ranging from 21G to 30G in diameter.
(Courtesy of Nanum Company Co., Ltd.)
3  Hyaluronic Acid (HA) Filler Injection Procedure

91
perforating a weakened vessel wall, particularly
when it comes to fine cannulas. Thus, extreme care
should be taken when forcing a narrow-­bore can-
nula such as a 27G or thinner through the tissue
since in such case, it may behave like a needle and
cut through the vessel if pushed in with too much
force. Personally, I had cases where I accidentally
perforated blood vessels even with a thicker 23-G
cannula, which lead to in massive hematomas. In
once case a female patient in her mid-70s came in
for the treatment of her nasolabial folds. She had
reported of having weak vessels and being prone
to bruising. Even with this knowledge, however, I
ended up rupturing her facial artery while advanc-
ing a 23-G cannula firmly from the lower cheek
toward the nasolabial fold. Likewise, vessels
trapped in the scar tissue due to a previous surgery
such as fat transplant, liposuction, rhinoplasty or
wounds can become highly susceptible to cannula-
tion even with a blunt cannula. In this regard, I had
a female patient in her mid-40s who presented for
filler treatment in her infraorbital/anterior malar
hollows with a history of a previous fat graft in the
same region. Postsurgical  scarring must have
caused either the angular a. or a detoured branch of
the facial a. to adhere to subcutaneous fat tissue. A
large hematoma occurred in this patient as I forced
a 23-G cannula through the tissue resistance. In
both cases, a bulging hematoma appeared immedi-
ately upon the rupture of the blood vessel, leaving
the patient to suffer from embarrassing bruises for
several weeks thereafter.
The other benefit of using a cannula lies in its
longer length which ranges between 3 and 7 cm
compared with a short 0.5-in. (1.25 cm) needle.
The longer reach of cannulas allows the practitio-
ner to fill wide areas of the face from a single
insertion point with greater consistency and in
considerably less time. This can be of particular
value when augmenting areas such as the nose
and forehead prone to irregularities due to their
underlying anatomy which consists of hard bone
directly underlying the thin soft tissue, allowing
bare minimum space for filler placement. Using a
cannula also dramatically saves time when filling
broad areas of the face such as the forehead. For
these reasons, I almost exclusively use cannulas
for augmenting the forehead apart from when
only partial corrections are required.
So, what are the relevant factors for selecting
the right cannula? Cannulas used for facial volu-
mization come in a wide variety of sizes, ranging
from 21G to 30G in diameter, of which 23G, 25G,
27G, and 30G are used most commonly (Fig. 3.5).
Bigger, thicker cannulas are more convenient to
use as they allow the product to flow more easily
but can cause more discomfort to the patient while
traversing through the tissues of the face. Thicker
cannulas are neither ideal for performing delicate
corrections that require precision and finesse. On
the other hand, smaller, finer cannulas can be less
painful and facilitate more detailed placement but
requires greater injection pressure and takes more
time to deliver the product as the material will
flow more slowly. Based on these characteristics,
the thicker 23-G and 25-G cannulas are more
commonly used for facial volume augmentation,
while the thinner 27G and 30G are utilized pri-
marily for the refinement of static folds and wrin-
kles rather than for volumetric augmentation.
Meanwhile, the choice of the cannula size may
also be significantly impacted by the rheology of
the HA filler to the injected. Specifically, biphasic
HA filler products such as Restylane® and Yvoire®
require the use of cannula sizes that correspond to
the particle size of the product. For example, the
use of a 21-G cannula is advised for injecting
large particle sized biphasic HA products such as
Yvoire Contour® to minimize possible deforma-
tion of the filler particles by shear stress while
they are extruded through the cannula. That not-
withstanding, in my practice, I have always used a
thinner 23G even for injecting these large particle
products to reduce patient discomfort and  pain
during the movement of a thick 21G in the tissue.
Nevertheless, I have observed no substantial com-
promise in filler longevity to date. I routinely use
a 30G for injecting finer particle-­sized Restylane®
fillers and a 27G for Restylane® Lyft which has a
relatively larger particle size. By contrast, mono-
phasic HA fillers such as the Juvéderm®,
Belotero®, and Neuramis® family of fillers allow a
higher degree of freedom in terms of cannula
sizes, as even the thicker, stiffer products indi-
cated specifically for facial volume augmentation
such as Juvéderm Voluma®, Belotero Volume®,
and Neuramis Volume® can, in theory, be deliv-
ered via a 29-G or even a 30-G cannula. While a
3.2  Injection Method

92
25G may, therefore, be reasonably used to inject a
monophasic HA filler for facial volume augmen-
tation, I prefer to use the thicker 23G in this case.
This is because while a thinner, narrower cannula
has the advantage of causing less pain, it requires
greater injection pressure and takes more time.
Moreover, it  has difficulty pushing through the
resistance of the ligamentous or scar tissues dur-
ing deep plane injection and tends to bend instead
of properly reaching the target site.
Cannulas, however, cannot completely replace
needles in all indications. For example, when
treating facial wrinkles with HA filler, a sharp
needle must be used for traversing through the
hard dermal layer. There are times when a needle
may also be used for placing volume in the sub-
cutaneous or subdermal planes. A case in point is
temples augmentation, where the use of a needle
becomes the preferred option, as the blunt can-
nula is incapable of penetrating the thick tempo-
ral fascia covering the temporal fossa to deliver
the necessary volume.
While some practitioners advocate the use of a
cannula in the temples and suggest the HA filler
may instead be placed in the space between the
superficial and the deep temporal facias, locating
this space with precision can be tricky and time
consuming. By comparison, a direct supraperios-
teal injection deep to the temporalis m. using a
21-G needle represents a much quicker and sim-
pler approach  without surface bumpiness. That
being the case, the temples represent the one
exception where I prefer to use a needle over a
cannula in a facial volumization treatments. The
needle sizes most often used for injecting HA fill-
ers are 27G, 29G, 30G, each 1.25 cm in length.
However, longer 23-G and 21-G needles can also
be employed when filling deep locations spanning
wide areas. Aspiration prior to filler injection is
vital when injecting with a needle to confirm that
it has not inadvertently entered a blood vessel. In
particular, when undertaking linear threading
technique, etc., where the tip of the needle con-
stantly changes position, aspiration should be per-
formed at each new location the needle tip is
moved to before depositing the filler. Entry of the
needle into the vein can be detected by aspiration
prior to injection. Meanwhile, penetration of the
deep temporal artery can be immediately identi-
fied by the instantaneous reflux of blood up the
syringe due to the arterial pressure (Fig. 3.6).
Note, however, that a negative aspiration test
does not guarantee 100% safety since finer nee-
dles in the 29-G or 30-G range do not aspirate
very well in very thin vessels such as those dis-
tributed in the nasal region. According to one
study in which 17 filler  products and different
needle sizes were used to aspirate ink reconsti-
tuted to concentrations similar to the human
blood, 47% of aspiration tests showed negative
results even when aspiration was performed using
the needle gauge recommended by the filler man-
ufacturer [5]. Moreover, the gauge of the needle
for the positive aspiration test was found to vary
according to the product [5]. At the risk of over-
generalizing, monophasic HA fillers were shown
Fig. 3.6  Photo of reflux blood in the syringe by aspira-
tion during a temple augmentation
3  Hyaluronic Acid (HA) Filler Injection Procedure

93
to be generally less amenable to aspiration com-
pared with biphasic HA fillers, requiring larger
bore needles to ensure adequate aspiration. It
may be reasonable to assume that this is due to
the rheologic property of monophasic HA fillers
that tend to be sticky and viscose in nature.
a
b
Fig. 3.7  Intravascular injection of HA fillers in the nasal
area. (a) The next day, that mottled erythematous patches
began appearing on the patients’ nose, glabella, and fore-
head. (b) Mottled erythematous patches became progres-
sively larger and darker 7 days after the injection
Episode:
Intravascular
HA
Filler
Injection in the Nasal Area
In my practice, I have  encountered five
cases of vascular complications from the
injection of HA filler in the nose with a
needle. Fortunately, none of these events
led to any disastrous consequence such as
skin necrosis or blindness, for which I
thank my ancestors for sending their good
karma my way. In three of those  cases,
the  vascular event  went unrecognized on
the day of the treatment due to lack of any
noticeable symptoms. In fact it was not
until the next day that mottled erythematic
patches began appearing on the patients’
nose, glabella, and forehead, becoming pro-
gressively larger and darker with time until
they resolved spontaneously in about
1  month without medical intervention
(Fig. 3.7) In the remaining two case, isch-
emic changes and skin blanching occurred
immediately following the filler injection,
to  which hyaluronidase was promptly
administered to dissolve the injected filler.
The patient achieved full recovery within a
week without any sequelae.
Three  of these events represented the
first three cases of intravascular filler injec-
tion I experienced since I began practicing
filler rhinoplasty in 2007. Coincidentally,
all three cases occurred contemporaneously
within a space of 1 month and involved the
use of a sharp needle and the same mono-
phasic Juvéderm® Ultra which I had newly
begun using around that time. Previously, I
had exclusively used biphasic Restylane®
products for injecting the nose. Preinjection
aspiration was duly performed in all three
cases, yet I failed to detect the inadvertent
vessel entry. Given that all three cases
occurred within the first month of my adopt-
ing Juvéderm® for injection in the nose, I
suppose my personal lack of experience is
partly to blame. More fundamentally
through, the rheologic property of mono-
phasic HA fillers not amenable to the aspi-
ration remains a more significant cause.
Needless to say, these events have since
veered me away from injecting monopha-
sic HA in the nose with a needle.
The remaining two cases involved the
use of the biphasic Restylane® fillers. In one
case, I had got distracted during a busy
day and neglected to aspirate before inject-
ing the filler in the nasal tip. As incredible as
it may sound, I was able to spot the problem
in the making as I actually witnessed the
filler particle shooting up the dorsum within
moments of entering the nasal tip. In the
3.2  Injection Method

94
final case, which turned out to be the most
colorful of them all, the patient had under-
gone two previous rhinoplasty surgeries,
after which she had the implant surgically
removed, 
which
left
her
with
a
depressed dorsum for which treatment was
desired. I had prior experience treating
patients with similar complex histories, all
of which had proven uneventful, so I pro-
ceeded with the treatment, mindful to aspi-
rate before each injection. Despite taking
utmost precaution, however, the patient
showed ischemic changes in the nose shortly
following the procedure to which hyaluroni-
dase was injected immediately to have the
filler reversed. The patient recovered with-
out sequelae in a week. Ironically, however,
this last case, which represented the mildest
of all five complications with the quickest
recovery, turned out to be the costliest, since
it eventually led the clinic to pay out about
5000 USD in monetary consolation to the
patient to stop her from sabotaging our busi-
ness with her daily protests.
In retrospect, a common thread can be
identified running through all five cases,
That is, all involve the use of a needle intro-
duced at the nasal tip. Unlike the vascular
supply of the nasion located at the superior
aspect of the dorsum, the vessels at the nasal
tip are narrower in diameter and are distrib-
uted across different tissue layers. As such,
a preinjection aspiration may not always
conclusively inform whether the needle had
Fig. 3.8  Linear thread
technique
inadvertently entered a blood vessel or not.
Since then, I abandoned the use of needles
for performing filler rhinoplasty and con-
verted to using only cannulas, which spared
me such problems during the past 10+ years.
Sometimes it does make sense to mend the
fence even after the horse has bolted.
3.2.2
Linear Thread Technique
This is the most commonly practiced technique
for augmenting facial volume or addressing deep
static lines and wrinkles with HA filler. The stan-
dard approach, referred to as the retrograde linear
thread technique, consists of injecting deep
beneath the fold to be corrected and depositing
the product along the direction of the said fold
while withdrawing the cannula/needle (Fig. 3.8).
The anterograde linear thread technique is
­conceptually the same except that the product is
deposited while the cannula/needle is being
advanced forward. However, anterograde linear
threading is less frequently used as it presents a
relatively higher risk of intravascular occlusion.
3.2.3
Tower Technique
In this technique, the needle is inserted perpendicu-
lar to the skin down onto the periosteum to build up
volume from the ground up. The product is depos-
ited deep to the subcutaneous tissue to extend verti-
cally from the periosteum toward the subdermal
3  Hyaluronic Acid (HA) Filler Injection Procedure

95
layer in the form of a tower (Fig.  3.9) [6]. The
advantage of this approach is that it avoids the risk
of entering the blood vessel along its length, as the
direction of the needle is perpendicular to the
course of the blood vessels. Erecting HA filler tow-
ers at strategic locations also carries the advantage
of reducing the amount of product needed to pro-
vide the necessary volumetric support. However,
results may not be as smooth and uniform as what
may be achieved with linear threading, and uneven-
ness may be palpable when touched by hand.
3.2.4
Fern Pattern Technique
(Multiple Intradermal
Injection)
This technique involves multiple intradermal
injections of HA filler made perpendicular to
the direction of the crease or fold to be cor-
rected along either side of said fold (Fig. 3.10).
The row of fillers placed on each side of the
fold resembles the shape of fern leaves with the
fold itself representing the stem, hence the
name fern technique (Fig. 3.11). Depositing the
HA filler at a right angle to the fold produces a
strong, robust dermal matrix resilient against
dynamic wrinkling. While the fern technique is
most frequently used for treating nasolabial
folds, it is also applicable for treating the
dynamic lines of the forehead and glabella.
Where the same strategy is replicated for use in
the wider regions of the face and body lacking
skin elasticity including the arms, legs, and
neck, it is referred to instead as hydrolifting,
signifying both the lifting effect (i.e., better
skin elasticity) and hydration the  HA filler
delivers to the skin (see Sect. 4.20). Hydrolifting
provides increased elasticity to the skin, which
is particularly helpful for tackling the appear-
ance of dynamic lines in the malar, the perioral,
and the cheek-areas that are not readily treat-
able with BoNT-A due to the risk of altering
the facial expression.
The desired depth of injection for hydrolift-
ing is at the deep dermis to minimize surface
irregularities. When injecting manually using a
30-G needle, a simple test would be helpful to
determine if the needle is located properly in the
deep dermis. Lifting the needle upwards from
under the skin, a clear silhouette of the needle
should be visible if the needle is properly placed
in the deep dermis (Fig. 3.12). A clear silhouette
of the needle is not visible when the needle is
inserted too deep into the subcutaneous layer,
while a needle inserted too superficially in the
Fig. 3.9  Tower technique
Fig. 3.10  Fern pattern
technique (multiple
intradermal injection)
3.2  Injection Method

96
upper dermis generates a gray bluish hue of the
needle visible through the skin. To prevent
bumpiness in thinly skinned areas, it is advis-
able to perform small-­volume injections target-
ing the deep dermis almost as if injecting the
subcutaneous layer. Bented needle at a 20−30
degree angle is helpful to facilitate even injec-
tion at the dermis using linear retrograde thread
technique.
3.2.5
Subcision Technique
This technique is used to release any fibrous scar
tissues (i.e., acne scars) present in areas of facial
volume deflation that anchor down the skin to the
underlying tissue layer  and  deter effective HA
filler placement. It is also applicable for address-
ing permanently etched-in grooves of the fore-
head, as  the skin overlying the groove is also
bound to the underlying tissue and has hardened
like depressed scars over time. The technique
involves manual severing of the scar tissue
strands using the bevel of a sharp needle, to
release the upper skin and create a pocket of
space for filler placement (Fig. 3.13). The proce-
dure may accompany bruising.
3.2.6
Double-Layering Technique
The double-layering technique  is a technique
indispensible to filler volumization, as it help to
deliver both definition and volume restora-
tion  without resulting in a bulky  appearance
(Fig. 3.14). It requires first injecting sufficient vol-
ume in the deep plane (using the linear threading
technique) before adding smaller volume in the
superficial plane to build a stack of HA filler
threads or HA filler towers sitting on two different
tissue layers. Attempting to pump in large volumes
in the deep plane alone to maximize projection
will likely cause the product to instead spread lat-
erally, leading to an unnaturally overdone appear-
ance such as the ‘Avatar nose’ or the ‘lion nose’
often encountered after an inadequate augmenta-
tion of the nasal dorsum. In this regard, the addi-
tional injection in the  superficial plane  plays an
important role in providing defintion and refine-
ment to the volume restoration. Double layering is
applicable to a wide range of filler indications. For
treatment of deep creases, for example, the filler
can be injected first  in the deep subcutaneous
plane to fill the groove to a substantial standard,
after which superficial refinement is made either in
the subdermal or dermal plane to achieve full lev-
a
b
Fig. 3.11  (a) Fern pattern technique for the treatment of dynamic nasolabial fold. (b) Fern leaves
3  Hyaluronic Acid (HA) Filler Injection Procedure

97
eling. It can also be used for addressing the infra-
orbital/medial malar depressions, by restoring first
the deep subcutaneous volume before addressing
the superficial volume in the subdermal layer for
additional projection. In nasal dorsum augmenta-
tion, injecting first the deep supraperiosteal plane
for the primary augmentation and subsequently in
the more superficial subdermal plane allows extra
elevation in nasal dorsum height without causing
the filler to migrate laterally.
3.2.7
Injection Technique for Deep
Static Grooves
This technique is used for addressing static
grooves and creases such as the deep glabella
lines and nasolabial folds. Drawing on the prin-
ciple of double layering, it involves first placing
a retrograde linear thread in the deep subcuta-
neous or supraperisoteal layer to fill the groove
to a substantial standard, before completing
a
b
c
d
Fig. 3.12  Image of a needle inserted into the dermis
depending on the depth of the injection. (a) Deep dermis.
A clear silhouette of the needle is visible. (b) The subcu-
taneous layer. A clear silhouette of the needle is not visi-
ble. (c) Upper dermis. A gray bluish hue of the needle
visible through the skin. (d) Bented needle at a 20-30
degree angle to facilitate even injection at the dermis
using linear retrograde thread technique.
3.2  Injection Method

98
with an intradermal or subdermal placement of
a retrograde thread for full leveling. The use of
a cannula is advised over a needle for deep sub-
cutaneous or subdermal injections to avoid the
risk of intravascular occlusion. A 30-G needle
is more ideal for performing superficial correc-
tions in the dermal layer. As previously noted,
in the case of permanently etched-in grooves of
the forehead or the glabella, the hardening of
the dermis like scar tissue over time, if not the
adhesion of the skin to the underlying subcuta-
neous tissue may prevent the injected filler
from providing the necessary lift. Such limita-
tions should be disclosed to the patient before-
hand, and overcorrection should be avoided in
such a case. In the alternative, the subcision
method may be combined to yield more favor-
able results.
Fig. 3.13  Subcision
technique
Fig. 3.14  Double-­layering
technique
3  Hyaluronic Acid (HA) Filler Injection Procedure

99
3.2.8
Volumizing Injection
Technique
Rule 1:  Double layering  technique; When
restoring facial volume depletion or enhancing
facial features such as the nose or chin (i.e., nasal
dorsum or chin augmentation), deep injection is
advised to build volume from the ground up, as
superficial injections just below the skin surface
provide only limited volumization. Caution is
required, however, when performing deep injec-
tions, as the injected volume will expand not only
anteriorly or superiorly but also laterally, leading
to an aesthetically displeasing bulky appearance
if placed in excess amounts. For example, over-
filling the nasal dorsum can widen the nose and
create the appearance of the “Avatar nose,” while
overcorrecting the chin can result in an exces-
sively bulky, blunt appearance of the chin. Also,
filling the cheeks to perfection in patients with
prominent jowls may only serve to accentuate the
jowls and exacerbate the saggy appearance. In
such case, the use of the double-layering tech-
nique for superficial refinements if not a slight
under-correction is advised.
Rule 2: Volume matters!; It also bears noting
that the primary purpose of volumizing fillers is
to literally fill out areas of volume deficit or
depletion. As such, achieving an aesthetically
desirable outcome can be elusive when working
with an insufficient amount of HA filler. To draw
an analogy, imagine filling a balloon with water.
To inflate the balloon to capacity, a certain thresh-
old volume of water is required. If not filled
enough, the balloon would remain loose and
saggy rather than becoming taut and tight. The
amount of water required to fill the balloon in this
case depends on the size of the balloon. That is,
the larger the balloon, the more water that is
needed. Likewise, the more severe the volume
deflation, the larger the amount of filler that is
required. Otherwise, contour irregularity would
continue to persist (Fig. 3.15).
Rule 3: Volumize the deepest part first; The
volumizing injection technique can be applied for
effective volumization of sunken areas of the face.
As the first step, map out an elliptical outline of the
volume-depleted area,  reflecting its overall size
and shape. Next, mark the longitudinal axis of the
elliptical outline, and create an entry point along
this longitudinal axis 1 cm lateral to the border of
the ellipse. Identify the deepest point of the depres-
sion (usually located at the center of the depres-
sion) and inject volume deeply into the
subcutaneous fat underlying this central point
using the retrograde linear thread technique. Upon
filling the central area to the desired height, repeat
the same approach in the adjacent left and right
areas to even out the contour (Fig. 3.16). When
redirecting the cannula to fill the adjacent left and
right areas, make sure to retract the cannula almost
all the way out of the entry point before forming a
new path different from the central path. Changing
directions mid-path may lead to surface irregulari-
ties and cause most of the injected volume to end
up at the center instead of the adjacent left and
Fig. 3.15  To inflate the
balloon to capacity, a
certain threshold volume
of water is required. If
not filled enough, the
balloon would remain
loose and saggy
3.2  Injection Method

100
right areas of the depression. As illustrated in
Fig. 3.16, this volumizing injection technique is
applicable to  forehead augmentation where the
aim is to fill out a concave forehead. Here, volume
is injected first into the central and deepest point of
the hollowness between the superciliary arch and
the frontal eminence, after which additional injec-
tions are performed in areas immediately above
and below the central deepest point to smoothen
out the contour.
Rule 4: Regard facial depressions as simpli-
fied 3D shapes; It is vital to analyze the face
from a three-dimensional perspective when
assessing the target area and envisioning the
desired outcome. Bear in mind that the face con-
sists of arcs and curvatures instead of straight
lines. One useful strategy for implementing a
three-dimensional facial assessment is to visual-
ize the facial depression in terms of simplified 3D
shapes such as a sphere, a cone, a triangular
prism, or an ellipsoid if not a water drop. Holding
a mental image of a water drop when evaluating
a facial depression, for example, informs that
when HA filler is placed to volumize the ellipsoi-
dal depression using the retrograde linear thread
technique, smaller volumes should be dispensed
at either end of the long axis plane while the bulk
of the volume should be injected in the middle.
On the short-axis plane, greater volume is to be
placed at the center relative to the adjacent left
and right aspects so that a smooth fluid curvature
is formed on the surface. Meanwhile, the fan of
columns deposited along the transverse plane
(using the fanning technique) should consist of
short columns outermost at the left and right bor-
der of the waterdrop or ellipsoid and progres-
sively longer columns toward the middle
(Fig. 3.17). For the relevant volumization tech-
nique pertaining to each facial region, see the
respective sections.
Rule 5: Leverage the effect of visual illu-
sions (Fig.  3.18): While it is impossible to
remove protrusions in facial contour using
injectable fillers, it is possible to visually
diminish or deemphasize their relative promi-
nence by padding volume in the adjacent areas.
This approach can be leveraged to obscure a
prominent lateral zygoma by filling the relative
hollows in the posterior cheek or temples (Fig.
1.4). By the same token, filling in the nasola-
bial folds and anterior cheeks and giving ante-
rior projection to the chin can balance out the
appearance of a protruded mouth. Meanwhile,
as facial proportionality is defined by the ratio
between the width and height of the face, a
wide or round face can be made to appear slim-
mer and longer by adding vertical length to the
chin (Fig. 1.5).
3.2.9
The Role
of the Nondominant Hand
The role of the nondominant hand is often over-
looked during filler procedures since the actual
injection is performed with the dominant hand.
Fig. 3.16  Volumizing injection technique for correction of forehead concavity
3  Hyaluronic Acid (HA) Filler Injection Procedure

101
However, the nondominant hand plays just as
important a function as the dominant hand during
the filler injection in the following respects. First,
the nondominant hand is engaged to pull the skin
opposite to the direction of the needle or cannula
to facilitate its insertion and traction under the
skin. Also, during nasal dorsum augmentation,
the thumb and index finger of the nondominant
hand is used to pinch the sidewalls of the nasal
dorsum to prevent widening of the nose. During
forehead augmentation, the nondominant hand
must be used to constantly mold and evenly dis-
a
b
Fig. 3.17  Three-dimensional perspective for volumiza-
tion. (a) A mental image of a ellipsoid water drop when
filling a facial depression. (b) Smaller volumes should be
dispensed at either end of the long axis plane while the
bulk of the volume should be injected in the middle. On
the short-axis plane, greater volume is to be placed at the
center relative to the adjacent left and right aspects so that
a smooth fluid curvature is formed on the surface.
Meanwhile, the fan of threads deposited along the trans-
verse plane (using the fanning technique) should consist
of short outermost threads at the left and right border of
the waterdrop or ellipsoid and progressively longer
threads toward the middle
Fig. 3.18  Leverage
visual illusion
3.2  Injection Method

102
tribute the HA filler immediately upon injection
to avoid surface irregularities. When treating the
sunken upper eyelids, the index and middle fin-
gers of the nondominant hand are used to press
down the eyeball for protection during cannula
advancement. See regional particulars for details
on the use of the nondominant hand.
3.3
HA Filler Injection Training
Employing the Use of Pig
Trotters
Practical challenges exist in the training of nov-
ice injectors on HA filler injection techniques.
First, HA filler procedures are performed pri-
marily by physicians in private practice rather
than by tertiary medical institutions such as uni-
versity hospitals specializing in training medi-
cal residents. Further, unlike surgical procedures
where the patient is typically placed under gen-
eral anesthesia, HA filler procedures are under-
taken with the patient alert and fully conscious,
which limits the opportunity for the teaching of
procedural skills, let alone the attendance by
trainees during the procedure. Under the cir-
cumstances, it is absolutely out of the question
for trainees go anywhere near an actual live
patient in-clinic for a practice session. This
being the case, beginning practitioners have lit-
tle choice but to take what techniques they have
managed to glean from watching live courses or
have learned over-the-­shoulder from advanced
injectors and to try them out first on their dear-
est and nearest (i.e., usually family members)
before going out on a limb to work with actual
patients. Due to the absence of systematic train-
ing, trials and errors are inevitable during this
process, subjecting injectors to various techni-
cal issues and adverse events which, in turn,
erode patient satisfaction and confidence.
In this regard, Allergan is known to have
developed facial injection dummies, which it
makes available for use by trainee injectors in
training courses. However, widespread use of
such dummies is limited by the relatively high
price point and lack of reusability. As an alterna-
tive, the author proposes the use of pig trotters for
simulating HA filler injection on patients
(Fig. 3.19a). The trotters of 1-month-old piglets
can be easily ordered in from local butcher shops
at an extremely affordable price of approximately
3–5 USD per cut. More than anything, they offer
the look and feel quite similar to that of the
human tissue. The grooves formed along the
ankle joints can effectively reproduce the struc-
tures of the nasolabial folds or deep furrows of
the forehead or glabella in a human face
(Fig. 3.19b). In addition, the curvatures present
on the calf provide an excellent platform for
practicing
facial
volumization
with
HA
(Fig. 3.19c). As the first step, the areas requiring
volume enhancement is marked out. Next, HA is
injected into center of the marked-out area (where
volume deficit is usually the greatest) using the
retrograde linear thread technique. Upon filling
the central area to the desired height, the same
approach is repeated in the adjacent areas to even
out the contour (see Sect. 3.2.8). Furthermore,
the skin of the pig’s trotters can be used by trainee
injectors to familiarize themselves with the intra-
dermal injection, fern pattern technique, and
hydrolifting technique (or multiple intradermal
injection of HA filler) (Fig. 3.19d).
HA fillers past their expiry date or without
cross-linking may be obtained from filler manu-
facturers upon request or purchase and used for
training purposes. Mixing a small amount of blue
dye with the HA filler can help establish the
depth of the injected HA filler after injection
upon dissction of the treated area. To mix the HA
filler with the blue dye, it is recommended to con-
nect the syringes holding HA filler and blue dye
onto a three-way or a “transfer” and pump the
liquid back and forth in a piston movement at
least 20 times.
3  Hyaluronic Acid (HA) Filler Injection Procedure

103
References
1. Seo KK.  Botulinum toxin for Asians. Singapore:
Springer Nature Ltd.; 2017. p. 175–6.
2. Kim HJ, Seo KK, Lee HK, Kim JS. Clinical anatomy
of face for botulinum toxin and filler injection. Berlin:
Springer; 2016. p. 28–31.
3. Heuss LT, Inauen W. The dawning of a new sedative:
propofol in gastrointestinal endoscopy. Digestion.
2004;69(1):20–6.
4. Kim HJ, Seo KK, Lee HK, Kim JS. Clinical anatomy
of face for botulinum toxin and filler injection. Berlin:
Springer; 2016. p. 169–73.
5. Casabona G. Blood aspiration test for cosmetic fill-
ers to prevent accidental intravascular injection in the
face. Dermatol Surg. 2015;41(7):841–7.
6. Sattler G.  Tower technique of filler injection. In:
Carruthers J, Carruthers A, editors. Soft tissue aug-
mentation. Philadelphia: Elsevier; 2018. p. 175–83.
a
b
c
d
Fig. 3.19  The use of pig trotters for HA filler injection
training. (a) The trotter of 1-month-old piglets. (b) The
grooves formed along the ankle joints can effectively
reproduce the structures of the nasolabial folds or deep
furrows of the forehead or glabella in a human face. (c)
The curvatures present on the calf provide an excellent
platform for practicing facial volumization with HA. (d)
The skin of the pig’s trotters can be used by trainee injec-
tors to familiarize themselves with the intradermal
injection
References

105
© Springer Nature Singapore Pte Ltd. 2021
K. K. Seo, Facial Volumization with Fillers,
Regional Particulars
4.1
Forehead Augmentation
Difficulty
Level:
C,
Effectiveness:
A,
Complications: C
The purpose of forehead augmentation is pri-
marily two-fold: to correct forehead concavity
and to address forehead sloping. Correction of
forehead concavity aims to smoothen the contour
of a concave or scalloped forehead by filling the
hollowness between the superciliary arch and the
frontal eminence (Fig. 4.1). In comparison, the
latter indication aims to rebalance a backward
sloping forehead on the lateral view by projecting
it slightly forward (Fig. 4.2).
Forehead concavity or a sunken forehead can
be caused either by the congenital bossing of the
frontal bone or by the progressive depletion of
frontal fat due to aging or weight loss, which
serves to  reveal the underlying protrusions and
depressions of the frontal bone structure [1]. Deep
forehead concavity accentuates the prominence of
the superior orbital ridge, a trait commonly asso-
ciated with a strong masculine image. Therefore,
forehead augmentation for a smooth convexity is
a commonly requested indication among young
female patients to create a softer, more feminine
facial appearance. Revolumizing a concave fore-
head also holds significant value for older patients,
as it helps to recreate the smooth youthful facial
contour lost to facial deflation and descent with
age, In brief, forehead augmentation serves  not
only as a beautification tool in young patients in
their 20s and 30s but also as a rejuvenation tool in
older patients in their fourth decade and above.
HA filler placed in the forehead is reasonably
expected to last between 5 and 10  years. The
4
Summary 1: 23-G Cannula is used for injec-
tion. Monophasic HA filler with high lift-
ing capacity and high cohesivity is
recommended.
Summary 2: Fillers should be placed at the
supraperiosteal layer under the frontalis m.
Summary 3: The relevant injection volume
is 2–6 mL for forehead concavity correc-
tion and 3–10  mL for forehead sloping
correction.
Summary 4: Pre-injection of botulinum
toxin  is highly advised prior to forehead
augmentation in order to avoid irregularites
caused by the movement of the  frontalis
and corrugator supercilii muscles. To
ensure overall  facial balance, concurrent
augmentation of the temples and the nose
should also be considered.

106
a
b
c
d
e
g
f
Fig. 4.1  Correction of forehead concavity ((a, c, e)
before, (b, d, f) after, (g) Superimposed image of forehead
before and after augmentation clearly domonstrates the
smoothened forehead concavity as well as the appropriate
location of the volume restoration
4  Regional Particulars

107
forehead, together with the nose and pretarsal
roll, represents an area where the duration of the
deposited HA filler tends to be the longest.
Presumably, this may be correlated with the spe-
cific technique employed for the placement, that
is, injection of boluses, which better protects the
HA filler against enzymatic biodegradation by
hyaluronidase. On the other hand, the limited
space available for HA filler placement in the
forehead, which consists of hard bone immedi-
ately underlying the thin soft tissue, means that
even when HA filler is delivered evenly in the
target
area,
subsequent
contractions
of
the ­frontalis muscle may cause the HA filler to
migrate and collect elsewhere, leading to the
appearance of lumpiness  in the forehead. To
Fig. 4.2  Correction of forehead sloping ((a, c, e) before,
(b, d, f) after, (g) Superimposed image of forehead before
and after augmentation clearly domonstrates the improved
sloping of forehead)
a
b
c
d
e
f
4.1  Forehead Augmentation

108
avoid such occurrence, preinjection of BoNT-A
in the frontalis and glabella 1–2 week(s) prior to
forehead augmentation is strongly recommended.
Optimum maintenance treatment for forehead
augmentation should preferably  consist of fol-
low-up BoNT-A injections repeated at regular
intervals rather than any periodic top-up of vol-
ume with HA filler. That said, results can be well
maintained without adjuvant BoNT-A injections
in patients who rarely animate the frontalis mus-
cle for conveying facial expressions.
4.1.1
Anatomical Considerations
The soft tissue  layers of the forehead from the
outer to inner consist of the skin—subcutaneous
layer—frontalis m. and galea aponeurosis—loose
connective tissue—periosteum [1]. Caution
should be taken when creating the entry points
with a needle to avoid perforating the vessels,
which in turn may bring about surplus  volume
change in the depressed area due to bruising. This
would disturb the appropriate placement of filler
for forehead augmentation. The relevant vessels
at risk include the sentinel v. and the superficial
temporal a. located lateral to the orbital rim as
well as the supratrochlear a. and supraorbital a.
located near the glabellar region [2]. Since all
these  vessels  run between the frontalis m. and
skin, the filler should be placed at the supraperios-
teal layer under the frontalis m. for the purpose of
avoiding intravascular  filler injection (Fig.  4.3)
[3]. Moreover, placing the filler under the fronta-
lis muscle is also helpful for preventing irregulari-
ties caused by the frontalis muscle movement.
4.1.2
Pretreatment Assessment
Pretreatment considerations include, among oth-
ers, the location and severity of the frontal con-
cavity, the gradient of the forehead slope, the
patient’s gender, dermal thickness, prominence
of the relevant mimetic muscles such as the fron-
talis m., and corrugator supercilii m., presence of
any blepharoptosis or eyelid hooding, as well as
such subjective factors as the patient’s expecta-
tion concerning the desired posttreatment volume
and contour improvement.
Location-wise, forehead concavity can be
present in the central forehead region and/or the
left and right lateral forehead above the eye-
brows. Whether to confine treatment to either the
central or lateral forehead depressions only or to
treat both aspects in tandem ultimately depends
on the location and the severity of the relevant
frontal hollowing. Note that in the case of pro-
nounced lateral forehead depressions, indenta-
tions can extend as far out as the hairline from
above the eyebrows.
The severity of frontal hollowness also
becomes a key pretreatment consideration since
it dictates the amount of volume to be placed.
The severity of forehead concavity can be graded
based on a five-point scale, scored as follows.
0 = an overall round convex forehead devoid of
concavities, projecting slightly forward when
viewed in profile, 1 = a flat forehead extending
from the frontal eminence to the supraorbital
ridge without any intervening depressions,
2  =  presence of mild depression between the
frontal eminence and the supraorbital ridge,
3 = presence of moderate depression in the said
region, and 4 = presence of severe depression in
the said region, representing frontal bossing in its
severest form (Fig. 4.4).
Concerning gender considerations, unlike in
female patients, full correction or leveling of
forehead concavity is not advised in men since
g
Fig. 4.2  (continued)
4  Regional Particulars

109
a
b
c
Skin
Subcutaneous fat layer
Frontalis m.
HA filler
Periostium
Loose connective tissue
Fig. 4.3  Depth of injection for forehead augmentation.
(a) Fillers should be placed at the supraperiosteal layer
under the frontalis m. for the purpose of avoiding intravas-
cular injection. (b) Sonography image displaying  the
evenly placed HA filler at the supraperiosteal layer. (c)
Proper placement of HA under the frontalis muscle on the
cadaveric forehead (courtesy of Pf. Kim Hee-Jin)
0
1
2
3
4
Fig. 4.4  The scale for grading the severity of forehead
concavity. 0: an overall round convex forehead, 1: a flat
forehead, 2: mild forehead concavity, 3: moderate fore-
head concavity, 4: severe forehead concavity
the appearance of a mildly rugged forehead with
slightly prominent superciliary arches is consid-
ered a desired masculinizing trait. Accordingly, a
reduced dose just enough to ameliorate the sever-
ity of the frontal irregularity is advised in the
male forehead, though actual volumes may vary
4.1  Forehead Augmentation

110
based on the patient’s subjective preference and
the desired forehead shape.
Meanwhile, the slant of the forehead describes
the degree to which the frontal bone slopes back-
wards from the superciliary arch up to the hair-
line. Forehead slant or sloping can be graded
according to the  inclination, with 0  =  slight
­protrusion of the forehead (on profile) anterior to
a line connecting the hairline and the superciliary
arch, 1  =  a straight forehead profile, with
the superciliary arch falling vertically from the
hairline, 2  =  mild sloping of the forehead,
3  =  moderate sloping, and 4  =  severe sloping
(Fig. 4.5) [4]. Asians are known to have more of
a backward-sloping forehead compared with
Caucasians [5].
4.1.3
Injection Technique
for Forehead Concavity
and Forehead Sloping
(Table 4.1)
The use of a 23-G cannula is advised to avoid
bruising and inadvertent intravascular injection
of filler. The relevant cannula entry points differ
in location depending on whether the correction
is for forehead concavity or forehead sloping. As
regards frontal concavities, medial forehead entry
points are created 1.5–2 cm superior to each eye-
brow along the respective midpupillary lines [1].
Meanwhile, the left and right lateral forehead
entry points are made 1 cm above the eyebrow
along a vertical line drawn 1 cm lateral to each
0
1
2
3
4
Fig. 4.5  The scale for grading the severity of forehead sloping. 0: an overall round convex forehead, 1: a flat forehead,
2: a mildly sloping forehead, 3: a moderately sloping forehead, 4: a severely sloping forehead
Table 4.1  Summary of forehead augmentation injection technique
Item
Contents
Needle vs. Cannula
23-G 5-cm Cannula
Choice of HA filler
Monophasic HA filler with high lifting capacity
Amount of HA filler
2–6 mL for correction of forehead concavity
3–10 mL for correction of forehead sloping
Depth of injection
Supraperiosteal layer
Entry point for
cannula
For forehead concavity, medial forehead entry points are created 1.5–2 cm superior to each
eyebrow along the respective midpupillary lines. Meanwhile, left and right lateral forehead
entry points are made 1 cm above the eyebrow along a vertical line drawn 1 cm lateral to
each lateral canthus
For forehead sloping, entry points are created 1–2 cm inferior to the hairline along
each lateral limbus line, while the left and right lateral entry points are made 2–4 cm
superior to each eyebrow along the respective lateral canthal lines
Target area
Correction of forehead concavity aims to fill the hollowness between the superciliary arch
and the frontal eminence
Correction of sloping forehead aims to volumize upper part of forehead under the hairline
Anesthetics
Supraorbital and supratrochlear nerve blocks
4  Regional Particulars

111
lateral canthus and (Fig. 4.6). Note that the pre-
cise location of cannula access points may also
vary according to the actual size and extent of the
frontal depression.
As regards forehead sloping, since the main
target of augmentation is the upper forehead
region extending to the hairline, medial forehead
entry points are made 1–2 cm inferior to the hair-
line along each lateral limbus line, while the left
and right lateral entry points are made 2–4 cm
superior to each eyebrow along the respective
­lateral canthal lines (Fig. 4.6). In either case, the
relevant plane of injection is the supraperiosteal
layer deep to the frontalis m (Fig. 4.3).
For the treatment of forehead concavity, insert
a 23-G cannula through the medial entry point on
the left mid pupillary line, and first fill the deep-
est (middle) part of the central forehead concav-
ity. The cannula should be inserted deeply down
to the periosteum and advanced practically scrap-
ing the surface of the periosteum. Once reaching
the right medial entry point, deposit the HA filler
a
b
Fig. 4.6  (a) Injection technique for forehead concavity, (b) Injection technique for forehead sloping
4.1  Forehead Augmentation

112
supraperiosteally while withdrawing the cannula.
Fill to the desired height maintaining constant
injection pressure to avoid unwanted contour
irregularities (Fig. 4.6).
Once the desired volume is achieved, repeat
the same technique in areas located immediately
above and below the deepest part (middle part) of
the central forehead concavity, extending up to
the frontal eminence superiorly and down to the
glabella inferiorly (Fig. 3.16). In case a mildly
convex forehead is desired, augment the middle
part  of  central forehead concavity  to project
slightly beyond  the frontal eminence  from
the profile view. Where instead a smooth straight
contour is preferred, the relevant areas should not
exceed the frontal eminence  from the profile
view but be treated just enough to blend with the
glabella region. Note, however, that even where a
convex forehead is desired, the forehead contour
should flow as a smooth arc from above the
patient’s own frontal eminence on the profile
view. In other words, care should be taken to not
to disproportionately augment the area below the
frontal eminence to such extent that it appears
unharmonious with the rest of the foreheard con-
tour. The right medial entry point should be cre-
ated only where necessary for treating a wide
forehead or a large central depression. Meanwhile,
the right and left lateral entry points should be
used for addressing the lateral forehead depres-
sions located on either side of the forehead. Here,
volume should be injected starting from just
above the eyebrows where the depression is the
deepest before tapering off towards the frontal
eminence, with progressively lower volumes
applied in the upper aspect.
Caution should be taken when creating the
lateral entry points with a 21-G needle to avoid
perforating the sentinel vein or the frontal branch
of the superficial temporal artery running nearby.
Also, to create a smooth gradation from the most
sunken point of the forehead toward adjacent
regions, make sure to taper the injection volume
accordingly, applying progressively lower vol-
umes in the upper and lower aspects of the cen-
tral forehead concavity and reduced volumes in
the upper/lateral aspects of the lateral depres-
sions. On the other hand, as regards forehead
sloping, insert a 23 G cannula through an medial
entry point at the upper forehead created along
the left lateral limbus line, and proceed first to
fill the upper central forehead near the hairline to
the desired height, before proceeding towards
the cannula entry point in the same manner. Once
the desired volume is achieved in the area close
to the central portion of the hairline, repeat the
same technique in the area located immediately
below, extending down to the frontal eminence
inferiorly in amounts adequate for projecting the
slanted forehead with progressively lower vol-
umes applied in the lower aspect. Next, repeat
the same process on the contralateral side of the
forehead slope using the opposite medial entry
point. Finally, using the lateral entry points cre-
ated along the right and left lateral canthal lines
place further volume to ensure a smooth transi-
tion to the lateral and inferior aspect of the fore-
head slope to achieve a smooth convexity in
forehead contour.
Regarding the choice of HA filler, the use of
soft, malleable monophasic HA filler is gener-
ally advised for the augmentation, given the lim-
ited space available for filler placement  in the
forehead. Also, monophasic HA filler with high
lifting capacity and high cohesivity is recom-
mended considering the movement of the fronta-
lis muscle  in the area. As regards the desired
dose, while actual injection volumes may vary
according to the severity of forehead concavity as
well as the volume desired by the patient, as a
general rule of thumb, 1–3 mL is indicated for
treating the  central forehead hollowness while
1–2 mL is required for the left and right lateral
forehead concavities. A mildly hollow forehead
(scoring 2 on forehead concavity scale) requires
2–3 mL, a moderately hollow forehead (scoring
3) 4–5  mL, while a  severely sunken forehead
(scoring 4) requires 6 mL or more of HA filler for
forehead augmentation. With respect to forehead
sloping, 3–5 mL of HA filler is required for aug-
menting a grade 2 forehead, 6–8 mL for grade 3,
and 10  mL or more for a grade 4 forehead
­primarily in the upper-mid portion of the fore-
head. The nondominant hand should be engaged
to constantly mold the injected HA filler to
smoothness. The use of 4 × 4 gauze molding
would be helpful to even out the forehead surface
after forehead filler injection (Fig. 4.7).
4  Regional Particulars

113
Anesthesia: Supraorbital and supratrochlear
nerve blocks are required to minimize the pain
and discomfort during the supraperiosteal place-
ment of HA fillers in the forehead (Fig. 3.4).
Upon applying the nerve block, massage and
wait for approximately 20 mins for the volume of
the injected local anesthetic to subside.
Preinjection of dental lidocaine intradermally in
the cannula entry points may  provide further
comfort. The patient should be made to under-
stand in advance that while the anesthesia helps
to numbs any significant pain during treatment,
they may still feel an odd sensation of the can-
nula scraping against their periosteum; and
that  in case the cannula were to hit a sensory
nerve, they may experience a sharp tingling sen-
sation radiating cephalically and a weird feeling
of hair on the vertex suddenly being tugged
backwards.
4.1.4
Combination Treatment
Pre-injection of botulinum toxin (BoNT-A) injec-
tion is highly advised prior to the filler injection
in the forehead to avoid irregularities caused by
the  frontalis and corrugator supercilii muscle
movement. For the same reason, a  follow-
up  injection of botulinum toxin repeated  every
3–6  months would be helpful for the optimum
maintanance of results especially in patients with
unconscious expression habit on the glabella and
forehead area. It would be necessary to make two
additional BoNT-A injections (0.5–1 U) above
the eyebrows, on the midpupillary line and along
the lateral canthal line  respectively,  in patients
displaying  active corrugator muscle movement
above the eyebrows when frowning (Fig. 4.8) [6].
For the purpose of ensuring optimum
facial balance, temple augmentation should be
Fig. 4.7  The 4 X 4 gauze molding would be helpful to
even out the forehead surface after forehead filler
injection
0.5U
1U
2U
3U
4U
Fig. 4.8  Injection
points of BoNT-A in
patients with an active
corrugator muscle
movement above the
eyebrows
4.1  Forehead Augmentation

114
concomitantly performed in patients with temple
depressions. In the same context, concurrent nose
augmentation would be required in patients with
a low-set nasal dorsum.
4.1.5
Complications
The most frequent and aesthetically displeas-
ing adverse event following forehead augmenta-
tion  is contour  irregularity. The limited space
available in the forehead between the frontal
bone and skin means the implanted HA filler,
unless placed evenly with meticulous care, is
prone to irregularity and clumping. In this respect,
the use of a cannula rather than a needle is
advised, since its longer length allows filling of
more areas from a single access point with less
trauma, creating a smoother and more even result.
Meanwhile, the noninjecting hand must be used
to constantly mold and evenly distribute the HA
filler immediately postinjection to remove any
irregularities. Where irregularities are present due
to a previous fat graft procedure, the injection of
HA would sometimes aggrevate such irregulari-
ties due to the scar tissues under the skin.
By the same token, a hyperactive frontalis or
corrugator m. can also result in the appearance of
dimpling or hollowing in the treated area, as the
pronounced
movement
of
these
muscles
may  cause volume to shift from its implanted
location. As such, BoNT-A injection is highly
advised prior to filler injection in the forehead.
And also, Care should be taken not to overfill the
central forehead, as it may create an odd local-
ized protrusion resembling the bump on a dol-
phin’s forehead. More importantly do not overfill
the lateral part of the forehead, which also results
in awkward bumpiness.
Necrosis due to intravascular injection of filler
may occur in the forehead when injections are
performed with needles. Other complications
include a sharp tingling sensation radiating
cephalically when the skin around the brow area
is touched, which may arise either as a side effect
of the nerve block or from a partial compromise
to the sensory nerves caused by the  cannula
movement during the treatment.
Episode: Forehead Augmentation
Nightmare
I refer to two nightmarish cases involving
forehead fillers dating back to the early
2000s when I had just started practicing fore-
head augmentation. The first case involved
an aspirant Korean idol trainee in his early
20s who presented with harsh frontal boss-
ing and bulging brow ridges which gave the
face a distinctly gorilla-like appearance.
Those were still early days when fillers
were used predominantly in the forehead for
addressing horizontal lines and creases, and
augmenting a sunken forehead was a novel
indication. Personally, I hardly had any prior
experience performing forehead volumiza-
tion  at the time. Upon starting the proce-
dure, I was instantly struck by the seemingly
inordinate amount of filler the patient’s fore-
head appeared to be consuming, even though
the angularity in the forehead contour
seemed to persist regardless of the volumes
being pumped in. I struggled laboriously for
more than 40–50 min to smoothen the con-
tour irregularity, to no avail.
On reflection, I realize that the problem
did not lie in placing too much volume but
rather the lack thereof. If I felt the 3–4 mL
I was injecting was a worryingly large
amount, it in fact  fell far short of the
6–10 mL advised for patients with such a
severely sunken forehead. Moreover, long
disposable cannulas had yet to be intro-
duced at the time, and it was tricky to
achieve uniformity using a 1.25 cm needle
to inject multiple areas across the vast fron-
tal area. Fortunately, with the subsequent
introduction of cannulas, I came to handle
even the most severely depressed foreheads
with a flourish in under 10 mins.
The young male patient had since gone
on to become a fairly renowned celebrity
who, to this day, sports a hairstyle covering
up his forehead. I feel bad for the young man
each time I see him on TV but, understand-
ably, he was never to return to my clinic.
4  Regional Particulars

115
The other case involved a young male
patient who manifested a severe horizontal
depression across the forehead like a deep
furrow. In this case, while the indentation
seemingly  diasppeared  immediately fol-
lowing treatment,  for some inexplicable
reason it would invariably reappear in about
a week. Three to four rounds of touch-ups
were provided, though to no avail, and the
problem ultimately went unresolved.
In hindsight, I now realize that the
patient may have been the type that relies
heavily on the use of forehead muscles to
lift the upper eyelid, in which case, the fre-
quent movement of the frontalis m. tends to
displace the filler from the deposited loca-
tion. Prior injection of BoNT-A in the fore-
head and glabella to relax and minimize the
muscle movement can help to avoid such
adverse events.
4.2
Temple Augmentation
Difficulty
Level:
A,
Effectiveness:
A,
Complications: B
Summary 1: Inject HA filler directly onto
the periosteum deep to the temporalis m.
using a 21-gauge  sharp needle and the
bolus injection technique  without with-
drawing the needle.
Summary 2: Care should be taken to avoid
the rich vasculature of the temple region to
prevent
bruising
and
embolization.
Preinjection aspiration is a prerequisite
when injecting with a needle.
Summary 3: To achieve the ideal oval face
shape by rounding out the zygomatic prom-
inence, HA filler should be injected in the
lateral part of the temporal fossa. To dimin-
ish the prominence of the orbital rim, vol-
ume should be placed at the medial and
superior aspects of the temporal fossa.
Recessed temples may either be a congenital
feature or caused by the loss of temporal volume
with aging or weight loss. Concavity in the tem-
ples creates a relative prominence of the adjacent
zygomatic and supraciliary arches, skeletonizing
the facial contour and giving the face a severe,
austere, and aged appearance. In this regard, tem-
ple enhancement serves not only to ovalize the
face by obscuring the prominence of the lateral
zygoma but also helps to create a softer, more
rested appearance by smoothening out the per-
ceived protrusion of the orbital rim (Fig. 1.4 and
Fig. 4.9).
4.2.1
Anatomical Considerations
The temporal fossa is delineated superiorly by
the superior temporal line, inferiorly by the zygo-
matic arch, medially by the superciliary arch and
the frontal process of zygoma, and laterally by
the temporal peak or the hairline down to the
sideburns. The soft tissue layers of the temporal
fossa from the outer to inner consist of the skin—
subcutaneous
layer—superficial
temporal
fascia —superficial layer of deep temporal fascia-­
temporal fat pad—deep layer of deep temporal
fascia-temporal extension of the buccal fat pad-­
temporalis m.-temporal bone [1]. The temporal
area is rich in blood vessels, and vigilance must
therefore be taken to avoid extensive bruising
from vessel injury or embolization from intravas-
cular filler injection. The relevant vessels at risk
include, among others, the sentinel v. located lat-
eral to the orbital rim, the superficial temporal a.
and v., the middle temporal v., and the deep tem-
poral a. and v. (Fig. 4.10).
The sentinel v. is present lateral to the eyes
and the brow, and is visible with the naked eye.
Careful observation is thus required during
injection to avoid the rupture of this vein since it
4.2  Temple Augmentation

116
a
b
c
d
Fig. 4.9  (a, c, e, g) Before and (b, d, f, h) after temple augmentation
4  Regional Particulars

117
can lead to severe bruising. The superficial tem-
poral a. runs between the superficial and the
deep temporal fascia and bifurcates into the
frontal branch and the parietal branch at a point
37 mm superior and 18 mm medial to the tragus
[7].The frontal branch of the superficial tempo-
ral a. courses obliquely in a superomedial direc-
tion toward a point located 2 cm superior to the
eyebrow on a vertical line drawn from the lateral
canthus (Fig. 4.11). The middle temporal v. as a
branch of the superficial temporal v. is situated
deep to the deep temporal facia and runs anterior
to the ear toward the orbital rim, approximately
2 cm or one fingerbreadth above and parallel to
the superior margin of the zygomatic arch
(Fig. 4.12). The deep temporal a. branching from
the maxillary a. gives off multiple small
branches, which within the substance of the tem-
poralis m., ascend superficially toward the mus-
cle surface (Fig. 4.10).
To sum up, from a clinical standpoint, the rel-
evant vessels to avoid during temple augmenta-
tion are the sentinel v. when filling the medial
aspect of the temporal fossa, the middle tempo-
ral v. when treating the inferior aspect, the deep
temporal a. when treating the deeper aspect, and
the superficial temporal a. when filling the supe-
rior aspect of the temple. While the sentinel v. is
­easily observed by the naked eye, the others are
deep structures hidden from view. Make sure to
perform slow injections of HA filler down into
the periosteum to avoid inadvertently entering
these structures. Aspiration before each injec-
tion must be performed as a matter of course to
minimize the risk of intravascular filler injec-
tion despite taking such precautions (Fig. 3.6).
Fig. 4.10  Arterial distribution in the temple
4.2  Temple Augmentation

118
Fig. 4.11  The superficial temporal a
Fig. 4.12  The middle temporal v
4  Regional Particulars

119
4.2.2
Pretreatment Assessment
It is first necessary to assess where and to what
extent volume is lacking within the temporal
fossa. Additionally, the patient’s subjective aes-
thetic goal for the treatment must be established
during consultation since the actual site and vol-
ume of injection varies depending on the respec-
tive indication. Confirm with the patient whether
the aim is to achieve an oval face shape by bal-
ancing out the prominent zygoma, or to create a
softer impression by smoothening the harsh tran-
sition to the orbital rim. Significantly, ethnic dif-
ferences in facial aesthetic standards must be
taken into consideration. For example, full
rounded temples are considered an auspicious
and favorable attribute among Chinese women
since, according to the traditional Chinese physi-
ognomy, it is believed to bring them a perfect
husband. Accordingly, when treating a Chinese
female patient, full leveling or convexity across
the entire temporal fossa is advised. On the other
hand, subtle concavity in the temples is consid-
ered a desired trait among Caucasians, as it high-
lights the malar eminence and completes the
Ogee curve regarded as essential to facial
­attractiveness in Caucasians (Fig. 4.13). By the
same token, temporal hollowing in men requires
less recontouring than in females since a slight
angularity in facial contour can be a masculiniz-
ing trait that lends more strength and charisma to
the face.
4.2.3
Injection Technique (Table 4.2)
As previously noted, the relevant area of injec-
tion within the temporal fossa differs according
to the specific indication. To ovalize the face by
deemphasizing the prominence of the lateral
zygoma, HA filler is placed in the lateral part of
the temporal fossa. To soften and blend the prom-
inence of the orbital rim, volume should be
directed toward the medial and superior aspects
of the temporal fossa. The medial and superior
temporal fossa are also targeted when temple
enhancement is undertaken in conjunction with
forehead augmentation to smoothen the transi-
tion between the relevant structures.
Significantly, the temple region represents the
one area where the author prefers to use needles
when performing volumization with HA filler.
Fig. 4.13  Ogee curve (Photo: Courtesy of Galderma)
4.2  Temple Augmentation

120
This is because the blunt tipped cannula is not
capable of piercing through the thick membrane
of the underlying superficial and deep temporal
facias. On the other hand, deep injection right
onto the periosteum using a sharp needle allows
for a quick and easy correction of volume defi-
ciency without leaving any surface irregularities.
For this reason, the procedure can be performed
even by novice injectors subject to following cer-
tain precautions. Standard precautions include
choosing the needle entry points with care to
avoid bruising, aspirating before each injection,
and pressing down the treatment area hard for 3
mins. post procedure to prevent the incidence of
hematoma formation. A 21-G long needle is used
for injecting the temple. The location and
­direction of needle entry and advancement vary
depending on the relevant indication.
Specifically, to soften the transition with the
orbital rim, the needle should be inserted deeply
at a point 1 cm posterior to the frontal process of
the zygoma and 1 cm superior to the zygomatic
arch, and advanced superomedially through to
the medial and superior parts of the temporal
fossa (Fig. 4.14a). To achieve an oval facial shape
by offsetting the prominent zygoma, the needle is
inserted deeply through the entry point created
3 cm behind the frontal process of the zygoma
and 1 cm above the zygomatic arch and guided
superolaterally to fill the deficiency in the lateral
aspect of the temporal fossa (Fig. 4.14b). Where
additional volume correction is desired immedi-
ately superior to the zygomatic arch, an entry
point is created 2.5 cm behind the frontal process
of the zygoma and 1  cm above the zygomatic
arch for making deep injection in the posterior
direction (Fig. 4.14c).
The needle should be introduced tangentially
to the skin at a 30°–45° angle with a downward-­
facing bevel until it reaches the bone. Once the
needle tip touches the bone, aspirate before
depositing a full 1 mL of HA filler right on the
bone without withdrawing the needle (Fig. 4.14d).
Unlike the retrograde threading technique typi-
cally employed in volumizing HA filler treat-
ments where the substance is deposited while the
instrument is being withdrawn, here, a full 1 mL
bolus is dispensed into the point of the most sig-
nificant volume depletion. The bolus of HA filler
diffuses evenly to adjacent areas in a smooth fluid
manner which the author postulates is most prob-
ably due to the tight cover, or resistance, provided
by the overlying structures of the temporalis m.
or the deep temporal facia. Where 1  mL falls
short of achieving the intended result, additional
volume may be placed in or around the injection
site. Any odd lumps or bumps from the injected
HA filler can easily be massaged and blended in.
Concerning the injection volume, 1–2 mL of
HA filler is usually dispensed per site, depending
on the indication. While 1–4  mL is generally
injected per side, as much as 5–6  mL may be
deposited per side in patients with a severe tem-
poral recess.
4.2.4
Complications
4.2.4.1 Bruising
Vessel injury during temple augmentation can
result in extensive bruising. Caution should be
exercised therefore to avoid the sentinel v. observ-
able by the naked eye and running in proximity to
Table 4.2  Summary of temple augmentation injection
technique
Item
Contents
Needle vs.
Cannula
21-G needle (Aspiration is
prerequisite prior to injection)
HA filler
Monophasic or biphasic with
high lifting capacity
Amount of HA
filler
1–4 mL per side
Depth of injection
Supraperiosteal or deep muscular
level
Entry point for
needle
Medial part: 1 cm behind the
frontal process of the zygoma
and 1 cm above the zygomatic
arch
Lateral part: 3 cm behind the
frontal process of the zygoma
and 1 cm above the zygomatic
arch. Additional entry point for
lateral part: 2.5 cm behind the
frontal process of the zygoma
and 1 cm above the zygomatic
arch if necessary
Target area
Medial part of the temporal
depression for smoothening the
orbital rim contour
Lateral part for the oval face line
Anesthetics
Topical anesthetics
4  Regional Particulars

121
the orbital rim. Regarding the deeper lying ves-
sels not immediately visible to the eye including
the superficial temporal a. and v. and the middle
temporal vein, an educated guess has to be taken
regarding their possible pathways. Note, how-
ever, that individual variations exist in the course
of these blood vessels and that deep structures
such as temporal a. may be at risk during the deep
periosteal injection. Therefore, compression of
the treatment area for at least 3 min is required
following treatment to prevent any unexpected
hematoma formation, Failure to do so may cause
the patient to experience immediate bulging at
the temporal fossa or lumpiness under the zygo-
matic arch on the following day as a result of the
­hematoma trickling downwards through tempo-
ral extension of the buccal fat pad (Fig.  4.15).
However, this should not be too much of a con-
cern since the hematoma typically resolves spon-
taneously in approximately 1–2 week.
4.2.4.2 Embolism
Given its extensive vascularity, the temple area is
susceptible to vascular embolism following treat-
ment with HA fillers or Sculptra [8]. In this
regard, the author’s preferred method of deliver-
ing HA filler supraperiosteally via direct needle
injection avoids the danger of severe vascular
injury apart from the potential risk to the deep
temporal a. and v. In each case, however, entry of
the  needle in the vessel is easily detectable.
Penetration of the deep temporal artery can be
immediately identified by the instantaneous
reflux of blood up the syringe due to the arterial
pressure (Fig. 3.6). Meanwhile, entry of the nee-
dle into the vein can be detected by aspiration
prior to injection. Withdrawal of blood upon aspi-
ration requires the needle to be removed and
bleeding to be controlled with firm pressure for
5 mins before the procedure can be resumed.
4.2.4.3 Headache
Headache may occur for 1–2  days following
treatment. Where persistent pain continues for
more than 1–2 weeks, it is best to dissolve the HA
filler with hyaluronidase. In my practice, I have
observed only  two cases  involving persistent
headaches following temple augmentation out of
a
b
c
d
Skin
superficial temporalis fascia
+ superficial layer of
deep temporalis fascia
temporalis fat pad
deep layer of
deep temporalis fascia
temporalis m
temporalis m
temporalis extension
of the buccal fat pad
HA filler
temporalis m
Fig. 4.14  Injection technique for temple augmentation.
(a) Medial aspect of temple depression. (b) Lateral aspect
of temple depression. (c) Inferolateral aspect of temple
depression. (d) Proper placement of HA filler for temple
augmentation as demonstrated by sonography
4.2  Temple Augmentation

122
the hundreds of cases performed. The fact that
symptoms resolved spontaneously upon dissolu-
tion of the HA filler suggests causation with HA
filler placement.
4.2.4.4 Irregularity
The author’s preferred approach of placing vol-
ume deep to the muscle avoids the risk of surface
contour irregularities as the taut overlying struc-
tures bear down on the injected HA filler and
even out its distribution. In contrast, superficial
injections into the subcutaneous fatty layer or
beneath the superficial temporal facia may result
in the appearance of lumpiness, which must be
dissolved away with hyaluronidase.
a
c
d
b
Fig. 4.15  Swelling developed at right buccal cheek 2
days after temporal volumization with HA filler. (a)
Before (b) 2 days after injection (c) Sonography of right
cheek clearly establishes the presence of hematoma,
hypoechoic mass under the subcutaneous fat layer. (d)
Sonography of normal cheek (left)
Tips: Use of needles and appropriate
level of the injection for temple
augmentation
While the author generally prefers the use of
a cannula in performing volumizing HA
filler treatments to minimize the risk of
bruising and embolization, temple augmen-
tation represents the one exception to the
rule. In the case HA filler is placed superfi-
cially into the subcutaneous fatty layer, the
thin skin overlying the temples is prone to
resulting in  product visibility, that is,
the appearance of visible lumps and uneven-
ness, and product  palpability where the
4  Regional Particulars

123
material tends to retrude and sink in when
pressed down with the hand. In the alterna-
tive, some practitioners suggest that strate-
gic placement of HA filler in the space
between the superficial temporal fascia and
the deep temporal fascia can achieve a more
uniform distribution of HA filler while
requiring less product than placements made
deep to the muscle. In this approach, it is
advised to pinch and lift the overlying skin
away from the underlying muscle to pave
the way for cannula advancement toward
the proposed target space, as the superficial
temporal fascia is attached to the skin while
the deep temporal fascia has adhered to the
muscle. However, it is not necessarily a
straightforward matter to determine whether
the right plane has been injected. Plus, the
risk of visible irregularities and product pal-
pability still exists though to a lesser degree
than subcutaneous injections.
On the other hand, deep supraperiosteal
injection using a 21-G long needle directly
on bone allows for a quick and easy correc-
tion of recessed temples without the risk of
surface irregularity thanks to the tight cover
provided by the overlying structures of the
temporalis m. or the deep temporal facia
(Fig.  4.14d). The procedure is simple
enough that it can be performed even by
novice injectors. To the extent that the nee-
dle is used for the injection, however, aspira-
tion prior to injection is a prerequisite.
4.3
Deep Glabella Furrow
Difficulty
Level:
B
Effectiveness:
A
Complications: C
Summary 1: Caution must be taken to avoid
the supratrochlear a. and supraorbital a. lying
close to the glabella furrows, as inadvertent
intravascular injection of HA filler into these
arteries may result in devastating conse-
quences of skin necrosis and blindness.
Summary 2: A glabellar “spread test” may
be performed to assess the extent to which
satisfactory
improvement
may
be
produced.
Summary 3: A 27-G × 3-cm cannula is used
to inject HA filler deeply into the subcuta-
neous fat layer above the periosteum (i.e.,
the supraperiosteal layer) as well as superfi-
cially in the subdermal layer. A 30-G nee-
dle should be used exclusively for
intradermal injections. Biphasic HA fillers
with medium-sized particles or monopha-
sic HA fillers with moderate viscoelasticity
are acceptable for use.
Summary 4: The adjunct use of BoNT-A is
required to relax the corrugator m. as the
underlying cause giving rise to the appear-
ance of dynamic glabella lines.
Loss of skin elasticity with age and repeated
wrinkling in the glabella complex over time leads
to the development of deep static glabella fur-
rows engraved in the form of number 11 (hence
the name “11 lines”) or the Chinese character for
“stream” (川). Unlike Caucasians who routinely
mobilize the muscles of the forehead and glabella
for communucating  a broad range of thoughts
and feelings, Asians tend to associate glabella
lines primarily with negative sentiments such as
frustration and anger, as these lines are consid-
ered to be formed principally by frowning and
scowling. For this reason, correction of glabella
lines represents the most popular indication for
BoNT-A treatment in Koreans [6]. However,
while the appearance of dynamic glabella lines
may be reversed with BoNT-A injections,
removal of deep static glabella furrows requires
filling in with HA filler (Fig. 4.16).
4.3.1
Anatomical Considerations
The supratrochlear a. and supraorbital a. arising
from the ophthalmic a. are located in the glabella
4.3  Deep Glabella Furrow

124
complex. The supratrochlear a. arises near the
medial canthus of the eye, while the supraorbital
a. emerges from the supraorbital foramen or
notch, and exits the orbit by piercing the orbital
septum before ascending superiorly to the fore-
head where it courses between the frontalis m.
and skin (Fig. 4.17) [7]. The supratrochlear a. not
only  lies relatively closer to the glabella fur-
rows compared with the supraorbital artery but
also runs superficially close to the skin surface.
Consequently, the supratrochlear a. is at a greater
risk of inadvertent intravascular filler injection
during the HA treatment of the glabella which
may result in subsequent necrosis of the skin or
loss of vision. That said, injecting within the
18–22 mm area between the supratrochlear arter-
ies is believed to be relatively safe because the
supratrochlear artery usually runs 9–11 mm lat-
eral to the midline of the glabella [8]. However, it
is important to note that there are many variations
in their branching pattern.
Though extremely rare, BoNT-A or local
anesthetic agents targeted at the glabella area may
accidentally be injected into the supratrochlear a.,
due to the proximity of the supratrochlear a.to the
relevant injection points. When this occurs, the
inadvertently injected BonT-A or nerve block can
actually be observed shooting up toward the fore-
head through the supratrochlear a. coursing
superficially beneath the skin surface. Supposing
the injected material consisted of HA fillers, the
occlusion of the supratrochlear a. in such case
would lead to the devastating complication of
necrosis of the forehead skin. Significantly, given
that HA filler for glabellar rhytide correction is
injected retrograde to the direction of the blood
flow of the supratrochlear a., the resulting back-
flow of the filler embolus into the ophthalmic a.
would most likely lead to the disastrous compli-
cation of visual loss (see Sect. 5.1.4). Significantly,
Beleznay et al. found the glabella to be the most
commonly implicated site of filler-related blind-
ness [9]. To avoid such dire consequences, the use
of a cannula should be preferred to the needle for
HA filler injections in the glabella, apart from
when addressing surface wrinkles in the dermis,
in which case, a needle should be used.
4.3.2
Pretreatment Assessment
To define the relevant treatment area, determine
first whether the furrows are configured in the
form of number 11 or the Chinese character for
stream (川) fanning out over a wider territory. It
must also be decided whether the patient requires
volume restoration of the deep furrows only or
additional refinement of static lines ingrained on
the skin surface like scratch marks. This is
because HA fillers are suitable primarily for fill-
ing in deep grooves or depressions, rather than
addressing skin surface changes. Permanently
etched-in glabella lines on the skin surface are
typically associated with textural changes on the
skin surface, as well as the adhesion of the skin
overlying these lines to the scar-like fibrous tissue
lying below. As such, superficial etched-­in lines
on the skin surface are generally not amenable to
treatment with HA filler alone (Fig. 4.18).
Consideration must also be given to any con-
current central forehead depressions above the
glabella region or any horizontal indentations or
depressions in the nasion located below. Under-­
correction is advised in patients with a prominent
a
b
Fig. 4.16  Deep glabella furrows. (a) Before and (b) after injection of HA filler
4  Regional Particulars

125
superciliary arch, as full leveling of the glabella
furrows in these individuals serves to highlight
the left and right superciliary ridges above the
medial canthus. A glabella “spread test” can be
used to determine the spreadability of the furrow
and the extent to which a satisfactory improve-
ment may be produced (Fig. 4.18).
4.3.3
Injection Technique (Table 4.3)
A biphasic HA filler with medium-sized particles
or a  monophasic HA filler with moderate
viscoelasticity is recommended for treating the
glabella region. For deep glabella furrows,
a 27-G × 3-cm cannula is used to deliver the HA
filler in the deep subcutaneous plane above the
periosteum (supraperiosteal layer) via the retro-
grade  linear threading technique  and subse-
quently in the subdermal layer to complete the
supraorbital a.
supratrochlear a.
dorsal nasal a.
angular a.
lateral nasal a.
inferior alar br.
superior labial a.
inferior labial a.
facial a.
18-22 mm
Fig. 4.17  Vascular
patterns of the nose and
glabellar region
Table 4.3  Summary of glabella furrow injection
technique
Item
Contents
Needle vs. Cannula
27-G 3-cm cannula for the deep
layer
30-G needle for the intradermal
layer
HA filler
Biphasic HA filler with
intermediate particle size or
monophasic HA filler with
moderate viscoelasticity
Amount of HA filler
0.3–1 mL
Depth of injection
Supraperiosteal layer and deep
subcutaneous layer
Intradermal layer for superficial
correction
Entry point
for cannula
0.5–1 cm above each furrow
Target area
Deep glabellar furrows rather
than the fine lines etched on the
skin surface
Anesthetics
Topical anesthetics
Nondominant hand
Hold the forehead skin upward
4.3  Deep Glabella Furrow

126
procedure (Fig.  4.18). A 30-G needle may be
used for superficial correction of residual surface
wrinkles in the dermal layer. To prevent inadver-
tent intravascular filler injection, the procedure
should be performed exclusively using a cannula.
The needle may be used only for performing
superficial corrections in the intradermal layer.
The cannula entry point is created 0.5–1  cm
above each furrow as it extends superiorly toward
the forehead (Fig.  4.19). The injection  volume
a
b
c
d
Fig. 4.18  Permanently etched-in glabella lines on the
skin surface are typically associated with textural changes
on the skin surface, as well as the adhesion of the skin
overlying these lines to the scar-like fibrous tissue lying
below. As such, superficial fine lines on the skin surface
are generally not amenable to treatment with HA filler
alone (a before and b after). A glabella “spread test” can
be used to determine the efficacy of filler injection for the
galbella furrow (c, d)
a
b
Fig. 4.19  Injection technique for deep glabella furrows. (a) HA filler placed in the deep subcutaneous plane above the
periosteum and subsequently in the subdermal layer. (b) The cannula entry point
4  Regional Particulars

127
usually ranges from 0.3 to 1 mL depending on the
depth or severity of the groove.
The use of topical anesthetic cream is suffi-
cient for local numbing. The nondominant hand
is used to stretch the forehead skin superiorly
during the injection. HA filler treatment of gla-
bella furrows should preferably be combined
with the BoNT-A injection to the corrugator m.,
the contraction of which triggers the appearance
of glabella furrows in the first place. In the
absence of adjunct BoNT-A injections, the
frequent movement of the corrugator muscles
may displace the HA filler from its originally
deposited location, leading to the recurrence of
glabella grooves or the migration of HA filler to
noninjected areas. Where concavities are concur-
rently present in the central forehead, volume
should also be added in the sunken forehead to
allow a smooth transition down to the glabella.
Likewise, in patients presenting with a congeni-
tally low nasion or horizontal indentation travers-
ing under the glabella, it is advisable to restore
volume in these areas simultaneously.
4.3.4
Complications
Irregularities: Full leveling of the glabella fur-
rows in patients with a pronounced superciliary
arch or a sunken central forehead may accentuate
the prominence of the superciliary arch.
Meanwhile, treatment of glabella furrows with
HA fillers alone without the combined use of
BoNT-A may cause migration and aggregation of
the injected HA filler due to surrounding muscle
contractions, resulting in contour irregularities.
Skin necrosis and blindness are also potential
complications (see Sect. 5.1.4).
4.4
Sunken Eyes Volumization
Difficulty
Level:
C,
Effectiveness:
A,
Complications: B
Hollowness in the upper eyelid is one of the
key indicators of an aging face. Sunken eyes, also
referred to as sunken upper eyelids, sunken supe-
rior sulcus, or upper eyelid hollowing, can occur
due to a multitude of factors. It can be caused by
a congenitally prominent orbital bony framework
typically found in Caucasians or can be associ-
ated with an underlying eyelid ptosis or a severe
dermatochalasis, in which case, the patient may
seek to compensate for their weak levator m. by
contracting the frontalis muscle to open the eye.
Supraorbital hollowing may also appear due to
the loss of septal fat volume with aging or weight
loss. Though rare, septal fat loss may also occur
due to its  aggressive removal during an upper
eyelid blepharoplasty. In Caucasians who tend to
have a narrow distance between the eyes and the
brow, the appearance of deep-set eyes is often
innately created by a combination of congenital
factors including the relatively protruded bony
orbit and the direct insertion of the levator palpe-
bral superioris m. into the dermis. By contrast, in
Asians with a wide distance between the eyes and
the brow, the levator m. attaches to the tarsus
rather than the skin, causing the septal fat to
descend and sit on the eyelid and contributing to
Summary 1: Treatment is performed with a
27-G 5-cm cannula. The target plane of
injection is the preseptal layer.
Summary 2: The cannula entry point is cre-
ated 0.3 mm lateral to the bony orbital rim
at the level of the lash line or the tarsal fold.
Insert the cannula at a 20°–30° angle to the
horizontal and coronal plane, and advance
along the margin of the orbital rim toward
the  superomedial direction. Place product
below the bony  orbital roof while with-
drawing the cannula.
Summary 3: Aim for a moderate under-­
correction of 50–70% improvement with
the eyes open to prevent the appearance of
bulges when the eyes are closed.
Summary 4: Identify the presence of any
eyelid ptosis or hooding as the underlying
cause of sunken eyes. Refer the patient for
surgery where conditions are severe.
4.4  Sunken Eyes Volumization

128
an innate fullness in the eyelid. For this reason,
hollowness in the upper eyelid in Asians tends to
impart an overaged appearance (Fig. 4.20).
The relevant solution to upper eyelid hollow-
ness varies according to the underlying cause of
the problem. Where the sunken appearance is
traceable to an underlying eyelid ptosis or derma-
tochalasis, surgical corrections such as a ptosis
surgery or blepharoplasty can provide the defini-
tive solution by obviating the need for compensa-
tory frontalis m. contraction for retracting the
eyelid upwards. Such improvements can be mim-
icked, to a certain degree, by use of BoNT-A for
relaxing the frontalis m. in patients with eyelid
ptosis (Fig.  4.21). On the other hand, where
the supraorbital hollowing is caused by the loss
of septal fat, correction is provided by replacing
the lost volume via surgical septal fat reposition-
ing, fat grafting, or HA filler placement. It bears
noting that sunken eye augmentation is a techni-
cally challenging procedure requiring extreme
precision and finesse in technique, as the molding
after the injection is almost impossible due to the
soft characteristics of eyeball. Moreover, the fine
skin overlying the upper eyelid tends to easily
reveal any filler imperfections, while the bumpi-
ness further increases when the eye is open and
closed.
4.4.1
Anatomical Considerations
From the outer to inner, the upper eyelid is lay-
ered as follows: the skin—subcutaneous fat—
orbicularis
oculi
m—preseptal
fat—orbital
septum—septal fat or intraorbital fat (Fig. 4.22)
The fat tissues of the upper eyelid consist of the
subcutaneous fat underlying the skin, the presep-
tal fat present anterior to the orbital septum, and
the septal fat, also known as the retroseptal fat or
the intraorbital fat lying behind the septum.
While the  septal fat constitutes the bulk of the
upper lid volume, volume replacement with HA
is directed primarily at the preseptal space since
the cannula cannot easily penetrate and reach
behind the rigid orbital septum.
4.4.2
Pretreatment Assessment
Assess the eyes for any underlying conditions
such as eyelid ptosis or hooding (dermatochalasis)
Fig. 4.20  (a, c) Before and (b, d) after sunken eye volumization
a
b
c
d
4  Regional Particulars

129
which may give rise to the sunken appearance.
Where conditions are severe, the patient should
be advised to undergo a definitive surgery instead.
While ptosis per se does not constitute a contrain-
dication for sunken eye correction with HA,
patients with droopy eyelids may occasionally
complain of perceived heaviness when opening
the eyes following treatment. In a vast majority
of cases, however, patients tend to express greater
comfort with which they can roll up their eye-
lids post-treatment. It can be conjectured that this
is due to the lubrication and hydration provided
by the HA filler placed between the septum and
the orbicularis oculi m.
Regarding patient selection, patients in their
late 50s and above presenting with severely
hooded eyelids are not ideal candidates  as  the
procedure may serve to exacerbate the redun-
dancy of the eyelid skin, reducing, if not elimi-
nating, the visibility of the pretarsal crease as a
result. On the other hand, patients with eyelid
ptosis manifesting an abnormally low position of
a
b
Fig. 4.21  Botulinum toxin injection for relaxing the frontalis m. in a 26-year-old patient with eyelid ptosis may improve
the sunken eye. (a) Before and (b) after injection
levator palpebrae superioris m
superior tarsal m.
orbital septum.
orbicularis oculi m.
tarsal plate
Fig. 4.22  Depth of
injection for sunken eye
volumization
4.4  Sunken Eyes Volumization

130
the upper lid margin may incidentally be pleased
to find that the volume replacement to their
supraorbital hollows has helped to restore the
folds to the normal height. Finally, the procedure
is not suitable for patients presenting with exoph-
thalmoses, as it may cause the bulging appear-
ance of the eyes to become more pronounced.
It is also important to assess the precise loca-
tion, that is, medial or lateral, and severity of the
volume loss in the upper eyelid. Note that less is
best when volumizing this area, and that the treat-
ment should aim for a moderate under-correction,
or a 50–70% improvement in the hollowness
with the eyes open, as even severe hollowness
is inconspicuous when the eyes are closed. Full
correction with the eyes open may thus result in
bulging of the lids when the eyes are closed.
4.4.3
Injection Technique (Table 4.4)
The upper eyelid is a delicate area of reduced skin
thickness, where volume replacement can often
result in lumpiness. Accordingly, reversible HA
fillers are the ideal choice for injecting this unfor-
giving area and are more preferable to other per-
manent products such as collagen stimulators or
fat grafts. Specifically, the use of soft and highly
spreadable monophasic HA filler is advised to
ensure a smooth and even distribution of filler.
A 27-G 5-cm cannula is recommended to
avoid damage to the eyeballs. The desired depth
of injection is the preseptal layer (Fig. 4.22). The
cannula entry point is created 0.3 cm lateral to the
bony orbital rim at the level of the lash line or the
tarsal fold (Fig. 4.23). Insert the cannula at a 20°–
30° angle to the horizontal and advance along the
margin of the orbital rim toward the superome-
dial direction.  More importantly, advance the
cannul at a 20°–30° angle posteriorly at the coro-
nal plane before touching the bony orbital
roof.  Place the  material below the orbital roof
while withdrawing the cannula. As noted above,
the relevant injection plane is in the preseptal
layer superficial to the septum, as penetrating the
tough, rigid orbital septum with a cannula is
extremely difficult and painful even if it were pos-
sible. Where hollowness is the severest in the
medial aspect of the upper eyelid, most of the
volume should be located in the medial hollows,
followed by HA filler delivered under constant
pressure along the orbital rim margin using the
retrograde linear thread technique. Finish the
injection 0.5  cm before reaching the lateral
orbital rim and remove the cannula. Check not
only for the presence of lumps when the eyes are
open but also for the appearance of bulges when
the eyes are closed. The upper eyelid is not ame-
nable to significant postinjection molding since it
is supported only by the soft eyeball with no hard
underlying structures to push against. The proce-
dure must, therefore, be undertaken in the first
place with utmost precision and caution. In case
protrusions appear when the eyes are closed, a
30-G cannula may be used to add HA filler sub-
dermally right below the protrusion to smoothen
the contour. The standard amount of HA filler is
0.2–0.5 mL per side. It is advisable to initially
inject 0.2–0.3 mL only and check for any bulging
of the eyelid when the eyes are closed. Additional
volume may be added as needed subsequently.
The nondominant hand should be used to press
down the eyeball for protection during cannula
advancement. Apart from the slight discomfort
felt when the eyeball is pushed downward, there
is hardly any pain during HA filler injection.
Concerning anesthesia, a local anesthetic applied
at the cannula entry point should suffice.
4.4.4
Complications
Irregularities: The skin overlying the upper eye-
lid is thin and prone to developing lumpiness
when injected with HA fillers. Hence, aiming for
Table 4.4  Summary of sunken eye augmentation
technique
Item
Contents
Needle vs. Cannula
27-G 4-cm
HA filler
Monophasic HA filler
Amount of HA filler
0.2–0.5 mL per side
Depth of injection
Preseptal layer
Entry point
for cannula
0.3 cm lateral to the bony
orbital rim
Target area
Sunken upper lid sulcus
Anesthetics
Local anesthetics at the entry
point
Nondominant hand
Press the eyeball downward
4  Regional Particulars

131
full correction with the eyes open can lead to the
appearance of lumps when the eyes are closed
(Fig.  4.24). Contour irregularities from HA
injection cannot be massaged in easily and should
rather be dissolved away.
Bruising: Care should be taken to avoid dam-
aging the sentinel v. or the superior palpebral v.
running in close proximity to the periorbital area.
Preinjection of dental lidocaine containing epi-
nephrine at the cannula entry point is advised to
reduce vascular injury.
Heaviness in the eyelid: Heaviness in the eye-
lid is an occasional occurrence in patients with
eyelid ptosis.
Narrowing or elimination of supratarsal
crease: Narrowing or elimination of the
supratarsal crease is an occasional occurrence in
patients in their late 40s and above presenting
with eyelid hooding or dermatochalasis.
a
b
Fig. 4.23  The entry point and the direction fo the can-
nula for sunken eye volumization (a) Insert the cannula at
a 20°–30° angle to the horizontal toward the superomedial
direction. (b) advance the cannul at a 20°–30° angle pos-
teriorly from the coronal plane before touching the bony
orbital roof
Fig. 4.24  Irregularity of the upper eyelid following HA
injection for the sunken eye
4.4  Sunken Eyes Volumization

132
4.5
Pretarsal Roll Augmentation
Difficulty
Level:
C,
Effectiveness:
A,
Complications: B
Pretarsal roll, or the hypertrophy of the pretar-
sal aspect of the orbicularis oculi muscle at the
lower eyelid, is a long “roll” formed along the
length of the lower tarsal plate upon the contrac-
tion of the orbicularis oculi while smiling. Since
the pretarsal roll generally becomes more pro-
nounced upon smiling, the presence of pretarsal
fullness at rest naturally imparts a soft, friendly,
and smiley impression. The visual effect of the
pretarsal roll on the lower eyelid is equivalent to
that of supratarsal crease on the upper eyelid in
terms of making the eyes appear larger overall by
adding an extra frame around the eye fissure. For
this reason, it is often dubbed “supratarsal crease
for the lower lid.” Volumizing the pretarsal roll
also has the incidental effect of reducing the
exposure of the lower white sclera in those with a
scleral show, diminishing the negative, scary
image associated with it.
From the Caucasian viewpoint, however, the
pretarsal roll may be considered a factor that
causes the relatively small palpebral aperture in
Asians to appear even smaller upon smiling. In
this regard, a BoNT-A indication had previously
been proposed for the removal of pretarsal roll in
Asians [10]. However, the result was deemed aes-
thetically undesirable from the Korean aesthetic
standard, and there are no doctors in Korea cur-
rently performing this indication to the best of
my knowledge. On the contrary, the pretarsal roll
represents one of the salient elements, together
with the small oval egg-shaped face, plump
cheeks, large eyes, and a tall narrow nose that
culminate in the ideal “Korean look” (Fig. 4.25).
Accordingly, volumizing the pretarsal roll with
HA fillers continues to be a popular indication
among many Koreans (Fig. 1.25 and Fig. 4.26).
Fig. 4.25  Cyborg embodying the “Korean look” featur-
ing a the small oval egg-shaped face, plump cheeks, large
eyes, pretarsal roll and a tall narrow nose
Summary 2: The use of a 30-G 3 cm can-
nula is advised to prevent bruising and
unwanted injection of HA filler into the
inferior medial palpebral artery (IMPA)
which runs along the eyelash under the
orbicularis oculi m.
Summary 3: The target depth of injection is
the subdermal layer, that is, between the
dermis and the pretarsal part of the orbicu-
laris oculi m. The shape of the pretarsal roll
should ideally resemble a banana, narrow
in the medial one-third, and slightly thicker
in the lateral aspect.
Summary 1: Pretarsal roll, or the hypertro-
phy of the pretarsal aspect of the orbicularis
oculi muscle at the lower eyelid, represents
one of the salient elements that culminate in
the ideal “Korean look.”
4  Regional Particulars

133
4.5.1
Anatomical Considerations
The anatomical layers of the lower eyelid from
the outer to inner consist of the skin—subder-
mal layer—orbicularis oculi m.—tarsal plate—
mucosa. At the pretarsal roll,  the inferior
medial palpebral artery (IMPA), a branch of
the ophthalmic a. runs along the eyelash
between the tarsal plate and orbicularis oculi
m. (Fig. 4.27) [7]. This arterial branch supplies
the tarsal plate of the lower eyelids and has a
diameter of approx. 1 mm at the medial can-
thus. For this reason,  injecting too deep near
the tarsal plate using a needle may cause intra-
vascular injection of filler directly through the
ophthalmic a. [11].
4.5.2
Pretreatment Assessment
Prior to treatment, due consideration must be
given to the patient’s age, skin elasticity, the width
and height of the eyes, the thickness of tarsal
plate (i.e., size of the pretarsal roll), presence or
absence of lower eyebag, as well as any history of
a previous lower blepharoplasty. Age should be
checked for the same reason as the patient’s skin
elasticity; patients in their fifth decade and above
and, for that matter, patients below the age of 50
but demonstrating skin laxity are at a greater risk
for developing contour irregularity or an overly
thickened pretarsal roll.
The thickness of the patient’s own tarsal plate
informs the potential shape and size of the
a
b
c
d
Fig. 4.26  (a, c) Before and (b, d) after volumizing the pretarsal roll with HA filler combined with the volumization of
sunken eyes and infraorbital hollows
4.5  Pretarsal Roll Augmentation

134
pretarsal roll to be obtained posttreatment, which
can be assessed by instructing the patient to smile
to trigger the contraction of orbicularis oculi m.
or by manually pushing the patient’s tarsal plate
upwards with a finger. The patient should be
advised, however, that the actual thickness of the
pretarsal roll created with HA is greater than
what is spontaneously generated by the contrac-
tion of the orbicularis oculi m. during smiling.
Whereas the pretarsal fullness from orbicularis
oculi contraction manifests in the form of a nar-
row roll under the lower lash line protruding for-
wards upon a smile, the pretarsal roll created with
HA is subject to pressure  from multiple direc-
tions which causes the deposited volume to dif-
fuse omnidirectionally, that is, expanding not
only anteriorly but also inferiorly, resulting in
greater thickness.
Next, assessment should also be made of the
width and height of the eyes, or more technically,
the horizontal length and vertical height of the
eye aperture. An overly thick pretarsal roll rela-
tive to the size of the eye aperture can appear dis-
proportionate and out of balance. Note that
pronounced pretarsal fullness on eyes with
short width of eye aperture creates a particularly
odd, worm-like appearance. The appropriate
thickness of the pretarsal roll relative to the width
and height of the eye aperture, based on measure-
ments taken of ten Korean female celebrities with
natural-looking pretarsal rolls including Tae-Hee
Kim, was found to be within 30% of the eye
width and 65% of the height (Fig. 4.28).
The presence of lower eye bags must also be
identified as any incorrect positioning of the HA
filler below the lower tarsal plate can exacerbate
the puffy appearance of the lower eyelid area. To
prevent such occurrence, the HA filler should be
placed as close to the lower lash line as possible
to create a sharp distinction from the infraorbital
fat located inferior to the pretarsal roll.
Alternatively, surgical removal of the eye bags
might be a more viable option where the lower
eye bags is such that it obscures the appearance
of the patient’s own pretarsal roll.
Note that pretarsal roll augmentation is rela-
tively contraindicated in patients with a history of
lower eyelid blepharoplasty or trichiasis surgery
(Fig. 4.29). Scar tissue adhesions formed in the
lower
eyelash
from
such
procedures
limit the space for HA filler placement along the
lash line and result in lumpiness even if the HA
filler is placed slightly inferior to the lash line.
That notwithstanding, pretarsal roll augmen-
tation may still be attempted despite such history
where the patient so desires, considering the vis-
ibly softer appearance it helps to foster. Besides,
reversing the HA filler is a straightforward matter
if the outcome turns out to be unfavorable. In the
author’s experience, one-third of the patients in
inferior orbital fat
tarsal plate
inferior medial palpebral a.
orbital septum
orbicularis retaining ligament
orbicularis oculi m.
suborbicularis oculi fat (SOOF)
Levator labii superioris m.
Fig. 4.27  Depth of injection for pretarsal roll augmentation
4  Regional Particulars