Operative Technique in Plastic Surgery – Kevin C.Chung

■ If the patient is ambulatory at baseline, patient is out of bed and ambulatory
on the first postoperative day.
■ Patients often return to work or normal activity 4 weeks following surgery.
■ Pedicled flaps for pressure sore reconstruction
■ The patient should remain inpatient, and pressure should be offloaded from
the SGAP flap for 2 weeks. This can be facilitated by the use of a special air
mattress or by having the patient in the prone position.
OUTCOMES
■ A small retrospective review comparing SGAP free flaps to DIEP flaps for
breast reconstruction reviewed equivalent flap and donor-site complication
rates.1,2
■ Another study comparing functional outcomes after SGAP-based breast to
DIEP-based breast reconstruction showed no significant lower extremity
functional scores.3
COMPLICATIONS
■ Donor Site Complications
■ Seroma
■ Hematoma
■ Contour deformities
■ Donor site pain
■ Flap complications
■ Artery or venous occlusion
■ Venous congestion
■ Hematoma
■ Seroma
■ Partial necrosis
■ Infection
REFERENCES
1. Gagnon AR, Blondeel PN. Superior gluteal artery perforator flap. Semin Plast
Surg. 2006;20:79-88.
2. Hur K, Ohkuma R, Bellamy JL, et al. Patient-reported assessment of
functional gait outcomes following superior gluteal artery perforator
reconstruction. Plast Reconstr Surg Glob Open. 2013;10:e31.
3. Hunter C, Moody L, Luan A, et al. Superior gluteal artery perforator flap: the

beauty of the buttock. Ann Plast Surg. 2016;76:S191-S195.

36
CHAPTER
Tissue Expansion for Trunk
Defects
Ibrahim Khansa and Jeffrey E. Janis
DEFINITION
■ Tissue expansion is the mechanical increase of the surface area of tissue. It
relies on two phenomena:
■ Creep: deformation of the tissue in response to stress
■ Stress relaxation: gradual decrease in the amount of force required to stretch
the tissue over time
ANATOMY
■ In the trunk, the tissues most commonly expanded for wound coverage are the
skin and subcutaneous tissue.
PATHOGENESIS
■ As the skin and subcutaneous tissue are expanded, all layers get thinner,
except for the epidermis, which undergoes cellular hyperplasia via mitosis.1
■ After removal of the tissue expander, all layers return to normal thickness,
except the adipose layer, which permanently thins.
■ Expanded skin has improved vascularity compared to nonexpanded skin.
■ Around the tissue expander, a capsule forms, consisting of collagen and
fibroblasts. The zone between the native tissue and the capsule is highly
vascular.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Tissue expansion is indicated when there is a local deficiency of soft tissue
coverage over a wound, with healthy tissue in the surrounding zone that is able
to be expanded.
■ Ask about history of radiation, because this makes radiated tissues much more

stiff and difficult to expand and increases the risk of tissue expander exposure,
infection, and/or loss.
■ On physical examination, look for infection/contamination, as this increases
risk of complications with tissue expansion.
■ In the lower abdominal wall, regional transfer of tissues from the anterolateral
thigh may be a better option for soft tissue coverage than tissue expansion.
However, in the epigastric region, those flaps may not have sufficient reach. In
addition, the epigastric region often has a scarcity of soft tissue, which
increases the usefulness of tissue expansion in this area.
IMAGING
■ No imaging is required specifically for tissue expansion.
SURGICAL MANAGEMENT
Preoperative Planning
■ Control contamination
■ Mupirocin nasal ointment and chlorhexidine baths for 5 days preoperatively
in patients at risk for methicillin-resistant Staphylococcus aureus (MRSA) or
who are known MRSA carriers.
• This protocol has been shown to reduce surgical site infections in total joint
arthroplasties.2
■ Optimize the patient to lower complication rates:
■ Glucose control: Hemoglobin A1c should be ≤7.4%.3
■ Nutrition: Albumin should be 3.25 g/dL or higher, and prealbumin should be
15 mg/dL or higher.3,4
■ Obesity: BMI should be 42 or lower and preferably below 40.3
■ Tobacco usage: Patients should quit all tobacco products for 4 weeks
preoperatively and 4 weeks postoperatively.3
■ Tissue expander selection
■ Choose largest tissue expander that can be placed in the pocket.
■ Length of the expander should be at least as long as the defect.
■ Crescentic and rectangular tissue expanders tend to be best suited for
abdominal wall defects. Rectangular expanders tend to have the highest
yield.5
■ Remote port tissue expanders are preferred.

Positioning
■ Supine with arms abducted 90 degrees, with all pressure points padded
Approach
■ The planned flap movement should be designed before tissue expansion is
begun. The incision to insert a tissue expander is usually made very close to the
border of the soft tissue defect. This helps minimize the amount of tissue
between the leading border of the flap and the wound, which will be discarded,
and provide for expansion of uninjured/unscarred tissue to transpose later
directly to the defect.
T E C H N I Q U E S
Video p5-c036_01
00:00 / 00:00
00:00 / 00:00

Video p5-c036_02
Subcutaneous Tissue Expander Insertion Into the
Abdomen
■ Prep the skin with alcohol-containing prep (chlorhexidine and alcohol or
iodine and alcohol).3,6 If a wound is present, use iodine alone.
■ Design an advancement or rotation flap, which, when expanded, will cover
the defect. The leading edge of the flap should be along one of the edges of
the defect (TECH FIG 1A).
■ Make an incision within 3 to 5 mm of the edge of the defect. This will serve
as the insertion access for the tissue expander and the leading edge of the
flap. The incision should not be made immediately at the edge of the wound,
as this incision will need to be closed and requires healthy tissue to obtain a
closure robust enough to protect the tissue expander (see TECH FIG 1A,D).
However, minimize the amount of tissue between the edge of the wound and
the incision, as this tissue will be discarded.
■ Dissect down to the anterior rectus sheath, and elevate the skin and
subcutaneous tissue off the rectus sheath from medial to lateral. The length
and width of the undermining should correspond precisely to the dimensions
of the tissue expander (TECH FIG 1B).
■ Once the precise pocket is dissected, create an additional small pocket for
the remote port. Through the dissected expander pocket, choose a location for
the remote port adjacent to the expander. The location should be chosen so
that the remote port is distant enough from the expander to avoid expander
puncture during fills, where the subcutaneous tissue is thinnest in order to
facilitate palpation of the port during fills, and preferably over a bony area to
provide support during needle access/insertion during fills. Dissect a small
pocket that will precisely fit the remote port. Do not overdissect, as this could
result in port migration or rotation.
■ Obtain hemostasis and irrigate with warm normal saline and triple antibiotic
solution.
■ A closed-suction drain is inserted into the pocket through a separate stab
incision laterally.
■ Use no-touch technique to insert the tissue expander:7

■ Re-prep the skin with Betadine and allow to try.
■ Use triple antibiotic irrigation (1 g cefazolin, 80 mg gentamicin, 50,000
units bacitracin in 500 cc of normal saline to irrigate the pocket and
immerse the tissue expander).8
■ Only one person touches the tissue expander. That person puts on new talc-
free gloves.
■ New retractors are used. They should be immersed in triple antibiotic
solution before use.
■ The skin is retracted using the new retractors, and the tissue expander is
inserted into the pocket without touching the skin (TECH FIG 1C).
■ The remote port can be sutured to the fascia if there is concern that it will
rotate or migrate.
■ The incision is closed in three layers using absorbable sutures (Scarpa fascia,
deep dermis, subcuticular), and dressings are applied (cyanoacrylate or
Xeroform) (TECH FIG 1D).
TECH FIG 1 • Tissue expander insertion. A. The

advancement flaps are designed, with the incisions
along the edges of the defect. B. Subcutaneous
pockets are dissected to precisely fit the tissue
expanders. C. The tissue expanders are inserted into
the subcutaneous pockets. D. Meticulous layered
closure is performed.
■ Tissue Expander Fill
■ Filling the tissue expander is begun 2 to 3 weeks after insertion (assuming
no wound healing problems). Fills are performed weekly.
■ The fill is performed after prepping the skin with chlorhexidine-alcohol. The
end points of filling are (a) patient pain and (b) skin blanching.
■ Filling is continued until the length of the flap overlying the tissue expander
is at least equal to the wound diameter plus the base width of the expander.
Judicious overfilling is preferable.
Tissue Expander Removal and Flap Advancement
■ The advancement or rotation flap is designed (TECH FIG 2A).
■ Before excising the wound or the skin graft on bowel, the previous incision
(for tissue expander insertion) is recreated along its full length, along with
any additional back cuts necessary to advance or rotate the flap.
■ The tissue expander and fill port are removed, and the pocket is irrigated
with warm normal saline.
■ The flap is advanced, transposed, or rotated as designed, and its ability to
close the defect is assessed.
■ If the flap cannot reach the distal end of the defect, several options are
available.
■ In a rotation flap, perform a back-cut, or Burow triangle, in order to
increase the rotation of the flap. The triangle should be designed to avoid
incising into the base of the flap, which may compromise vascularity.
• Another maneuver is to incise the fascia underneath the intact skin at the
point of maximal tension, which will allow for further excursion.
■ In an advancement flap, undermine farther laterally to increase

advancement. This should be performed carefully as it will decrease the
vascularity of the flap. Back-cuts can also be performed unilaterally or
bilaterally.9
■ Perform capsulotomies in the tissue expander capsule. These should be
performed perpendicular to the desired direction of advancement (TECH
FIG 2B). They should be performed carefully, incising through capsule
only and avoiding injuring the flap itself. Multiple capsulotomies can be
performed, spaced approximately 1 cm from each other. Extrapolating from
galeal scoring in scalp reconstruction, the tension should be checked after
each capsulotomy, and additional capsulotomies performed if more
advancement is needed.10 Capsulectomies are not recommended, as they
can decrease flap vascularity.
■ Only excise part of the wound, and leave the remainder for a later serial
excision or second round of expansion.
■ After the reach of the flap is verified, the wound is excised (partially or fully,
depending on flap reach), and the flap is advanced/rotated and inset. A
closed-suction drain should be placed under the flap (the capsule will tend to
form a seroma unless the pocket is drained).
TECH FIG 2 • Tissue expander removal and skin
advancement. A. The advancement flap is re-
elevated, and the tissue expander is removed. B.
Capsulotomies perpendicular to the advancement
vector can be performed to increase flap excursion.
■ Other Techniques
■ Some authors have described expansion of the external oblique,11 of the

internal oblique-external oblique complex,12,13 or of the entire abdominal
wall musculofascia using intraperitoneal tissue expanders.14 However, these
techniques lead to thinning and attenuation of the musculofascial layer and
have not gained widespread use.
PEARLS AND PITFALLS
Planning
■ The planned flap movement should be designed before the incision for
the insertion of the tissue expander is made.
■ Most patients require multiple tissue expanders to be placed. In most
cases, one tissue expander can be placed on either side of the wound,
and filling of both expanders can be performed concurrently.
Surgical
technique
■ The capsule is highly vascular. Performing a capsulectomy at the time
of tissue expander removal and flap advancement risks skin flap
compromise and hematoma formation. Capsulotomies can be
performed perpendicular to the desired advancement vector to increase
flap excursion.
■ Infection and extrusion are major complications that can result in
sabotage of the expander-based reconstruction due to need for tissue
expander removal. Therefore, meticulous attention to patient selection,
sterile technique (both in the OR and during postoperative expansion),
and adherence to end points of tissue expansion are paramount.
POSTOPERATIVE CARE
■ After tissue expander insertion
■ The drain should be kept in until its output is less than 20 cc/day for 2
consecutive days with the patient ambulatory. This end point may not be
reached until tissue expander fills are begun, as the tissue expander starts to
fill the dead space.
■ Many surgeons keep patients on antibiotics to cover skin flora while the
drain is still present and in contact with the tissue expander. There is no
evidence to support or contradict this practice, and the published evidence is
inconclusive.15,16
■ After tissue expander removal and flap advancement
■ The drain should be kept in until its output is less than 20 cc/day for 2
consecutive days with the patient ambulatory.

OUTCOMES
■ Outcomes are generally good, even in the presence of ostomies or
enterocutaneous fistulas. These can increase the rate of infection and add
morbidity and reoperations. Despite that most patients can usually complete the
expansion process successfully.17–20
COMPLICATIONS
■ Tissue expander infection
■ If mild cellulitis with no systemic symptoms, attempt treatment with oral or
intravenous antibiotics.
■ If severe or with systemic symptoms, requires surgical washout and tissue
expander removal.
■ Tissue expander exposure
■ Usually requires washout and tissue expander removal. If infection is present,
no new expander should be inserted. If no infection is present, a new tissue
expander can potentially be inserted after washout.
■ Seroma
■ If threatening skin flap viability, aspirate or perform interventional radiology
drain insertion
■ If not causing a problem and not infected, can potentially observe and wait
for resolution
■ Hematoma
■ Requires washout as hematomas that are not evacuated will lead to capsular
scarring, which would make flap movement very difficult
■ Skin flap necrosis
■ If causing tissue expander exposure, requires washout and debridement and
expander removal
■ If occurs after tissue expander removal and flap advancement/rotation, can
usually treat with local wound care until demarcated and then may require
debridement
REFERENCES
1. Johnson PE, Kernahan DA, Bauer BS. Dermal and epidermal response to soft-
tissue expansion in the pig. Plast Reconstr Surg. 1988;81:390-397.
2. Sporer SM, Rogers T, Abella L. Methicillin-resistant and methicillin-sensitive
Staphylococcus aureus screening and decolonization to reduce surgical site
infection in elective total joint arthroplasty. J Arthroplasty. 2016;31:144-147.

3. Harrison B, Khansa I, Janis JE. Evidence-based strategies to reduce
postoperative complications in plastic surgery. Plast Reconstr Surg.
2016;137:351-360.
4. Kudsk KA, Tolley EA, DeWitt RC, et al. Preoperative albumin and surgical
site identify surgical risk for major postoperative complications. J Parenter
Enteral Nutr. 2003;27:1-9.
5. van Rappard JHA, Molenaar J, van Doorn K, et al. Surface-area increase in
tissue expansion. Plast Reconstr Surg. 1988;82:833-837.
6. Darouiche RO, Wall MJ, Itani KM, et al. Chlorhexidine-alcohol versus
povidone-iodine for surgical-site antisepsis. N Engl J Med. 2010;362:18-26.
7. Mladick RA. “No-touch” submuscular saline breast augmentation technique.
Aesthetic Plast Surg. 1993;17:183-192.
8. Khansa I, Hendrick RG, Boehmler JH, et al. Breast reconstruction with tissue
expanders: implementation of a standardized best-practices protocol to reduce
infection rates. Plast Reconstr Surg. 2014;134:11-18.
9. Zide BM, Karp NS. Maximizing gain from rectangular tissue expanders. Plast
Reconstr Surg. 1992;90:500-504.
10. Leedy JE, Janis JE, Rohrich RJ. Reconstruction of acquired scalp defects: an
algorithmic approach. Plast Reconstr Surg. 2005;116:54e-72e.
11. Jacobsen MW, Petty PM, Bite U, Johnson CH. Massive abdominal-wall
hernia reconstruction with expanded external/internal oblique and transversalis
musculofascia. Plast Reconstr Surg. 1997;100:326-335.
12. Byrd HS, Hobar PC. Abdominal wall expansion in congenital defects. Plast
Reconstr Surg. 1989;84:347-352.
13. Hobar PC, Rohrich RJ, Byrd HS. Abdominal-wall reconstruction with
expanded musculofascial tissue in a posttraumatic defect. Plast Reconstr Surg.
1994;94:379-383.
14. Marin-Gutzke M, Mirelis E, Sanchez-Olaso A, et al. Restoring the abdominal
cavity space by intraabdominal and extraabdominal tissue expansion. Plast
Reconstr Surg. 2008;121:359-360.
15. Phillips BT, Fourman MS, Bui DT, et al. Are prophylactic postoperative
antibiotics necessary for immediate breast reconstruction? Results of a
prospective randomized clinical trial. J Am Coll Surg. 2016;222:1116-1124.
16. Wong A, Lee S, Sbitany H, et al. Postoperative prophylactic antibiotic use
following ventral hernia repair with placement of surgical drains reduces the
postoperative surgical-site infection rate. Plast Reconstr Surg. 2016;137:285-
294.

17. Paletta CT, Huang DB, Dehghan K, Kelly C. The use of tissue expanders in
staged abdominal wall reconstruction. Ann Plast Surg. 1999;42:259-265.
18. Carr JA. Tissue expander-assisted ventral hernia repair for the skin-grafted
damage control abdomen. World J Surg. 2014;38:782-787.
19. Kuokkanen H. Tissue expander-assisted ventral hernia repair for the skin-
grafted damage control abdomen. World J Surg. 2014;38:788-789.
20. Watson MJ, Kundu N, Coppa C, et al. Role of tissue expanders in patients
with loss of abdominal domain awaiting intestinal transplantation. Transpl Int.
2013;26:1184-1190.

37
CHAPTERKeystone Flaps
Theodore A. Kung and Peter C. Neligan
DEFINITION
■ The keystone flap is a versatile fasciocutaneous flap that transfers available
soft tissue to an adjacent defect and can be designed anywhere on the body
where perforators are present. It serves as a reliable alternative to more
complex forms of reconstruction, such as free tissue transfer, and can be used
for large as well as small defects.
■ Advantages of keystone flaps include simple and rapid dissection that results
in relatively shorter operative times compared to alternative reconstructive
options, techniques that are easily reproducible and teachable, and
reconstruction with local tissue of similar quality. In addition, although
keystone flaps are based on perforating vessels, there is no need to perform a
meticulous perforator dissection.
■ Appropriate use of a keystone flap over other choices of reconstruction (eg,
muscle flap with skin graft, myocutaneous flap, free flap) can minimize donor-
site morbidity and facilitate a more expeditious postsurgical recovery.
ANATOMY
■ The keystone flap is a fasciocutaneous advancement flap. The donor-site
secondary defect is addressed by performing two V-Y closures.
■ Knowledge of the location of musculocutaneous and septocutaneous
perforators can facilitate design of well-vascularized keystone flaps (FIG 1).
■ Anteriorly, perforators from the internal mammary, intercostal, and epigastric
systems can supply keystone flaps for chest and abdominal reconstruction.
■ Posteriorly, midline closures may take advantage of paravertebral intercostal
perforators. Multiple perforators arising from the subscapular system may be

used to design keystone flaps for the mid and upper back. Lower back and
buttock keystone flaps can include perforators from the posterior intercostal,
lumbar, and gluteal systems.
■ In upper and lower extremities, numerous perforators from the major
longitudinal vessels can supply keystone flaps of various sizes. For larger
defects, named perforators can be used to ensure adequate vascularity to the
flap (eg, perforators from the descending branch of the lateral circumflex
femoral artery), whereas smaller defects may depend on randomly distributed
perforating vessels emanating from the underlying fascia and muscle.
■ One notable location where keystone flaps may fail is the scalp due to its axial
blood supply and relatively unyielding quality.
■ In principle, to close a defect with a keystone flap, the volume of the keystone
flap needs to be redistributed in order to fill nearly all of the primary and the
secondary defect (the total defect size, primary plus secondary, is modestly
reduced during closure due to advancement of the wound margins). Thus, the
keystone flap is not an ideal choice to fill large concave defects. In those
instances, one should consider reconstructive options that provide additional
tissue volume.

FIG 1 • Keystone flaps may be designed based on
knowledge of the location of major perforators and their
vascular territories. ATA, anterior tibial artery; BA,
brachial artery; DCA, dorsal carpal arch; DIEA, deep
inferior epigastric artery; DPA, dorsalis pedis artery; FA,
facial artery; IGA, inferior gluteal artery; ITA, internal
thoracic (mammary) artery; LA, lumbar arteries; LPIA,

lateral branches of posterior intercostal arteries; LTA,
lateral thoracic artery; MCFA, medial circumflex femoral
artery; MPA, medial plantar artery; PA, popliteal artery;
PBA, profunda brachial artery; PFA, profunda femoris
artery; PIOA, posterior interosseous artery; PNA,
peroneal artery; PTA, posterior tibial artery; RA, radial
artery; SEA, superior epigastric artery; SFA, superficial
femoral artery; SGA, superior gluteal artery; SIEA,
superficial inferior epigastric artery; TAA,
thoracoacromial artery; TDA, thoracodorsal artery; UA,
ulnar artery.
■ More than one keystone flap can be designed around a defect in order to
distribute the tension burden of secondary defect closure.
HISTORY
■ As described by Behan in 2003, the keystone flap is a trapezoidal perforator
advancement flap. The name is derived from the flap’s resemblance to the
shape of an architectural keystone within an ancient Roman arch.1
■ The keystone flap has been successfully applied to a vast array of clinical
scenarios, including reconstruction of the trunk, head and neck, extremities,
and perineum.2–7
■ Multiple variations of the keystone flap have been described. These include
the use of more than one keystone flap, a rotational keystone flap, and an
omega-variant technique.1,8
PATIENT HISTORY AND PHYSICAL FINDINGS
■ The potential use of a keystone flap can be noted preoperatively during
physical examination. Patients should be counseled that flap selection is
ultimately based upon the dimensions of the defect as well as the laxity of the
surrounding tissues. Therefore, other possible reconstructive options should
also be reviewed with the patient before surgery.
■ For reconstruction after tumor extirpation, knowledge of the necessary surgical
margins is helpful to predict if adequate local tissue will be available for design
of a keystone flap. Extensive surgical margins commonly result in a wide
concave defect that demands a significant amount of volume replacement. On

these occasions, the keystone flap may not provide sufficient volume for
coverage.
■ The need for preoperative or postoperative radiation therapy should be noted.
A keystone flap using soft tissues that have been previously radiated can
demonstrate significantly decreased laxity and may not adequately advance
into the defect. When postoperative radiotherapy is planned, the well-
vascularized keystone flap can be expected to sustain radiation without major
complications.
IMAGING
■ Imaging studies are not required for successful design of a keystone flap, but
oftentimes, preoperative CT scans obtained for surgical planning are helpful to
identify perforators.
■ Use of a handheld pencil Doppler probe can assist in identifying perforators to
help design the keystone flap. Smaller keystone flaps supplied by random
perforating vessels may not demonstrate Doppler signals but can still be used
successfully.
■ Although the viability of the keystone flap can be readily determined by
clinical examination alone, if there is any question about the vascularity of the
flap after harvest, intraoperative fluorescent angiography can be used to
confirm both arterial inflow and venous outflow. A fluorescent dye such as
indocyanine green is injected intravenously, and arterial inflow is confirmed
within 30 seconds as the dye flows into the keystone flap. After about 20
minutes, venous outflow can also be confirmed by observing the absence of
dye within the flap.
SURGICAL MANAGEMENT
■ Keystone flaps are commonly utilized in the reconstruction of tumor
extirpation defects. These flaps provide durable soft tissue coverage and well-
vascularized tissue capable of sustaining adjuvant radiation therapy.
■ Some resection defects are quite large and involve full-thickness removal of
skin, fat, muscle, and bone (eg, sarcoma excision) (FIG 2). Many of these
defects would otherwise require the use of a pedicled muscle-based
reconstruction method or a free flap. Alternatively, resection defects can be
small but located on difficult locations, such as the hand or foot and ankle,
where reliable soft tissue coverage is needed to protect underlying tendon and
bone (FIG 3).

■ In the trunk and proximal extremities, where multiple robust perforators are
known to exist, the keystone flap should always be a reconstructive option,
especially when there is substantial soft tissue laxity adjacent to the defect.
FIG 2 • Wide excision of a sarcoma of the lateral back.
A large keystone flap was used to advance skin and
soft tissue from a posterior to lateral direction. Adequate
exposure is critical to designing a keystone flap of
sufficient size to fill such a large defect.
FIG 3 • A,B. Smaller defects can also be closed using
keystone flaps. A dorsal hand wound resulting from

excision of a melanoma is closed with a keystone flap
based on underlying perforators of the dorsal
metacarpal arteries. Importantly, no undermining should
be attempted to preserve vascularity for smaller
keystone flaps.
■ For more distal defects, such as those on the hand or foot, a keystone flap may
still be used; however, one must be particularly careful not to undermine the
flap in an effort to preserve vascularity.
■ A keystone flap can be used in conjunction with another local flap to close
especially large defects.
■ Secondary defects resulting from harvest of another flap can be closed with a
keystone flap. For example, when a wide flap containing skin (eg, radial
forearm, parascapular, anterolateral thigh, etc.) is needed for reconstruction and
the donor site cannot be approximately primarily, a keystone flap can be
designed to permit closure of the secondary defect.
Preoperative Planning
■ In the vast majority of cases, a keystone flap can be designed based upon
knowing the location of key perforators near the site of the defect. Thus, there
is rarely a need for dedicated preoperative imaging for the sake of the keystone
flap.
■ A handheld pencil Doppler probe can be used to confirm the presence of major
perforators.
■ Alternatively, intraoperative fluorescent angiography can be performed to
identify the location of perforators.
Positioning
■ When a keystone flap is to be performed after tumor extirpation, coordination
with the oncologic surgeon is critical to determine the optimal positioning for
reconstruction.
■ Adequate exposure of the surrounding tissues is critical to properly design a
keystone flap.
Approach
■ Design of a keystone flap is individualized to each patient and requires

consideration of the shape and size of the defect, the surrounding soft tissue
quality and laxity, and the most favorable placement of scars.
T E C H N I Q U E S
■ Technique for Keystone Flap Design
■ The skin and soft tissue around the defect are palpated to determine the areas
of maximum laxity.
■ Classically, for an elliptical defect, each limb of the keystone flap is drawn at
a 90-degree angle to each end of the defect (TECH FIG 1A). For a circular
defect, these limbs must be designed such that the inner corners of the
keystone flap are not excessively narrow in order to optimize vascularity and
advancement (TECH FIG 1B). Alternatively, a circular defect can be first
converted into an elliptical defect, or, the keystone flap may be modified to
obviate the need for excision of normal tissue (TECH FIG 1C).
■ The width of the keystone flap should be equal to or slightly greater than the
width of the defect.
■ All edges of the keystone flap are incised, and dissection is carried down
through the underlying deep fascia. The deep fascia must be completely
incised to maximize flap mobility.
■ Normally, the perforators that feed the keystone flap are not visualized.
■ If adequate mobility permits, the inner corners of the keystone flap may be
trimmed away in a rounded fashion.
■ Closure begins by placing a stitch at the point of maximum tension. Next,
the outer corners of the keystone flap are closed in a V-Y fashion. Finally, the
halving principle is used for the remainder of the closure to distribute the
tension.
■ If there is excessive tightness during closure, several strategies can be
considered:
■ Check that the deep fascia at the margins of the keystone flap has been
adequately incised.
■ Perform limited undermining of the keystone flap while preserving any
visualized perforators.
■ Superficially incise the underlying muscle at the edges of the keystone flap

to gain additional mobility.
■ Undermine the soft tissues surrounding the defect to recruit more laxity at
the point of maximum tension.
■ Turn the inner corners of the keystone flap toward the defect so that the
tips of these corners become the leading edge of the keystone flap. This
technique is possible only if the inner corners are sufficiently vascularized
(ie, if the tips are not excessively narrow).
■ Consider performing a second keystone flap on the other side of the defect.
TECH FIG 1 • A. Keystone flap closure of an elliptical
defect. The donor site is closed in a V-Y fashion, and
this aids in flap advancement. B. With a circular
defect, the inner corners of the defect must not be
excessively narrow. Wider inner corners will result in
improved vascularity and a larger keystone flap, which
facilitates flap advancement. If adequate mobility
permits, the inner corners may be trimmed away in a
rounded fashion. C. As an alternative to converting a
circular defect into an elliptical defect, the keystone
flap may be modified to avoid excising normal tissue.
■ Keystone Flap for Back Reconstruction
■ Midline back defects are especially amenable to bilateral keystone flap
closure (TECH FIG 2).
■ Each flap is supplied by robust perforators, and the advancement
requirement for tension-free closure is shared by the two flaps.

TECH FIG 2 • A-D. Excision of a large sarcoma from
the midline lower back resulting in a large defect that
cannot be reapproximated. Tension-free closure was
achieved by performing bilateral keystone flaps.
■ Keystone Flap for Foot Reconstruction
■ A keystone flap can be used on glabrous skin of the hand or foot (TECH
FIG 3).
■ In these locations, the skin is firmly adherent to the underlying fascia.
Complete release of the fascia is mandatory to maximize flap advancement.
■ If necessary, tissue scissors can be used to spread in a vertical fashion
perpendicular to the plane of the skin. This technique releases the multiple
subcutaneous septa and results in greater flap mobility.
TECH FIG 3 • A-C. An ulcerating plantar foot lesion is
excised, resulting in exposure of the plantar fascia.
Due to the adherent nature of plantar skin, two
opposing keystone flaps were planned. However, after

complete release of the plantar fascia and vertical
spreading along the margins of the flap, the defect
was successfully closed with only one keystone flap.
■ Keystone Flap to Close a Donor-site Defect
■ When reconstruction calls for a large fasciocutaneous or musculocutaneous
flap involving a wide skin paddle, the secondary defect may not close
primarily.
■ As an alternative to skin grafting, which results in poor appearance and may
lead to contour deformity, a keystone flap can be designed to fill the donor-
site defect (TECH FIG 4).
TECH FIG 4 • A,B. A keystone flap can be used to
close a secondary defect after harvest of a
fasciocutaneous or musculocutaneous flap. A radial
forearm flap was harvested for coverage of a palmar
hand defect following resection of a sarcoma. The

resultant donor-site defect could not be closed
primarily. Therefore, a keystone flap was designed to
transfer mobile volar forearm skin and soft tissue to
achieve closure of the secondary defect.
PEARLS AND PITFALLS
Design
■ The dimensions of the keystone flap must be of sufficient size to
close the intended defect.
■ The width of the keystone flap must approximate the width of the
defect, or else closure may be excessively tight or even impossible.
■ A large keystone flap will ensure inclusion of more perforators.
■ The V-Y closures of the keystone flap should be designed to
maximize advancement of the flap into the primary defect.
Technique
■ A handheld pencil Doppler probe may be used to help identify
perforators.
■ In rare instances, the keystone flap requires cautious undermining.
If so, every effort should be taken to preserve perforators.
■ Underlying muscle may be superficially incised along the borders
of the keystone flap to permit additional advancement, if
necessary.
■ The first closure stitch should serve to close the primary defect.
Subsequently, the secondary defect is closed using the halving
principle in order to even distribute tension.
Postoperative
■ Patients should be placed on appropriate activity restrictions
specific to the anatomic region where a keystone flap was
performed. This will minimize the rate of dehiscence.
■ Superficial wounds can be treated conservatively with dressing
changes. These minor wounds should not delay any planned
postoperative adjuvant radiation.
POSTOPERATIVE CARE
■ The patient is restricted from any movements that increase tension on the
keystone flap, especially along the short axis of the flap. A postoperative splint
may be beneficial for a short period of time when the reconstruction is on an

extremity.
■ Physical therapy consultation is helpful for some patients after reconstruction
of large lower extremity defects.
■ Non–weight bearing for about 2 weeks after foot and ankle keystones
■ The patient is seen within 1 week after discharge and then for suture removal
at the 2-week postoperative visit.
OUTCOMES
■ Keystone flaps have been utilized to close a wide variety of defects and boasts
a success rate of 97% to 100%.2,6
■ Major complications requiring a secondary operation are rare; minor
complications commonly involve superficial wound dehiscence that can be
treated conservatively.
■ Compared to other coverage options, such as muscle-based flaps or free flaps,
appropriate selection of a keystone flap for reconstruction can result in shorter
operative time, shorter inpatient stay, and shorter time to patient mobilization.
COMPLICATIONS
■ Delayed wound healing can occur at points of relative tension along the
keystone flap incisions. In the vast majority of cases, these wounds are
superficial and can be treated with dressing changes.
■ Frequently, planned postoperative adjuvant radiation therapy is not initiated
until the reconstruction has sufficiently healed. Superficial wounds should not
delay initiation of radiation therapy. For larger wounds, secondary
interventions such as split-thickness skin grafting may be considered to hasten
wound closure in anticipation of radiation therapy.
■ Rarely, keystone flaps may demonstrate venous congestion in the immediate
postoperative period. Consider releasing some sutures to relieve tension,
application of nitropaste, or the use of leeches. Also, evaluate if patient position
and mobility is contributing to the problem.
■ Seromas are a rare occurrence after keystone flaps because undermining of the
surrounding tissues is generally not necessary.
REFERENCES
1. Behan FC. The keystone design perforator island flap in reconstructive
surgery. ANZ J Surg. 2003;73:112-120.
2. Khouri JS, Egeland BM, Daily SD, et al. The keystone island flap: use in large

defects of the trunk and extremities in soft tissue reconstruction. Plast Reconstr
Surg. 2011;127:1212-1221.
3. Behan FC, Rozen WM, Azer S, Grant P. ‘Perineal keystone design perforator
island flap’ for perineal and vulval reconstruction. ANZ J Surg. 2012;82:381-
382.
4. Moncrieff MD, Bowen F, Thompson JF, et al. Keystone flap reconstruction of
primary melanoma excision defects of the leg: the end of the skin graft?. Ann
Surg Oncol. 2008;15:2867-2873.
5. Behan F, Sizeland A, Gilmour F, et al. Use of the keystone island flap for
advanced head and neck cancer in the elderly: a principle of amelioration. J
Plast Reconstr Aesthet Surg. 2010;63:739-745.
6. Mohan AT, Rammos CK, Akhavan AA, et al. Evolving concepts of keystone
perforator island flaps (KPIF): principles of perforator anatomy, design
modifications, and extended clinical applications. Plast Reconstr Surg.
2016;137:1909-1920.
7. Pelissier P, Gardet H, Pinsolle V, et al. The keystone design perforator island
flap. Part II: clinical applications. J Plast Reconstr Aesthet Surg. 2007;60:888-
891.
8. Behan FC, Rozen WM, Lo CH, Findlay M. The omega - Ω - variant designs
(types A and B) of the keystone perforator island flap. ANZ J Surg.
2011;81:650-652.

38
CHAPTER
Treatment of Axillary
Hyperhidrosis
David L. Larson
DEFINITION
■ Hyperhidrosis is excessive sweating beyond the normal physiologic response
to heat or emotional stimuli.
■ Any such sweating is excessive when it so negatively affects the daily life of
individuals that their normal interactions with the world around them are
compromised.
ANATOMY
■ The greatest concentration of eccrine (sweat-producing) glands is in the palms,
axilla, and soles of the feet, where only about 5% of the glands are normally
active at any one time.1
■ These glands are located in the subcutaneous tissue of the axilla and not in the
dermis (FIG 1)—a fact that is of particular significance when considering the
rationale for and effectiveness of axillary shaving in the treatment of
hyperhidrosis.
PATHOGENESIS
■ Primary hyperhidrosis is not psychological in nature, is not self-limiting, and
can significantly impact quality of life (QOL), as validated by QOL scales,
showing it to be comparable to end-stage renal disease, rheumatoid arthritis,
multiple sclerosis, and severe psoriasis.2,3
■ Secondary hyperhidrosis is associated with many common diseases (eg,
Parkinson’s, hyperthyroidism, gout), conditions (eg, pregnancy, obesity,
menopause), and drugs (eg, neuropsychiatric, antimicrobials, urologic) that can
cause diaphoresis. Once these etiologies have been ruled out by history and/or

pattern of sweating, a diagnosis of primary or idiopathic hyperhidrosis should
be entertained.
NATURAL HISTORY
■ Though previously viewed as a benign condition, it is now recognized as a
potentially extremely debilitating disease, impairing the social interactions and
occupational activities of those affected.
■ Affecting 1.4% of the US population, axillary hyperhidrosis generally appears
spontaneously in puberty or early adulthood (less than 30 years old). About
one-third of these patients will be so negatively affected by the embarrassment,
need of frequent change of clothes, and/or malodor that it may eliminate
careers such as education, sales, and marketing.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Many patients (over 40%) will not seek medical aid because of
embarrassment, the thought that nothing can be done, or misdirection by
caregivers (eg, “learn to live with it”).

FIG 1 • Anatomy of the skin and its adnexa.
■ Diagnosis is made primarily by history, which includes focal, visible,
excessive sweating of at least 6 months duration without apparent cause. In
addition, there must be at least two of the following characteristics: bilateral
and symmetric, impairment of daily activities, at least one episode weekly,
onset in youth (eg, 13 to 25 years old), positive family history (usually positive
in 25% of patients), and cessation of sweating during sleep. Many times, all of
these findings are noted.
■ The only physical finding is excessive moisture in the affected area.
IMAGING/DIAGNOSIS
■ Diagnosis can be confirmed by measuring the transepidermal water loss
(g/m2/h) using a VapoMeter (Delfin Technologies, Stamford, Connecticut)
(FIG 2).4
■ Alternatively, the Minor test (starch-iodine test) can be used for confirmation:
■ Clean and thoroughly dry the axilla.
■ Paint the entire underarm with iodine solution or povidone-iodine.
■ Use a makeup brush, sifter, or gauze pad to evenly dust the site with fine
starch powder.
■ After 10 to 15 minutes, areas of sweat will turn the mixture dark purple-blue,
which should be documented with a photo.
DIFFERENTIAL DIAGNOSIS
■ N/A
NONOPERATIVE MANAGEMENT5
■ Topical antiperspirants: “clinical-grade” topical deodorants have usually been
initiated by the patient. Locally applied powder can also be used, but Drysol
(prescription item) only lasts 3 to 4 days, is messy, is difficult to apply, and
causes local skin irritation.
■ Oral anticholinergics: Robinul (1 mg bid and increase 1 mg q 2 weeks until
effective) or oxybutynin (2.5 mg daily × 7 days, then 2.5 mg bid × 5 weeks) is
sometimes effective. Generally, side effects (eg, blurred vision, dry mouth,
constipation, etc.) limit the effectiveness, but these should still be the initial
treatment.

FIG 2 • VapoMeter provides practical, reproducible, and
rapid measurement of sweating in g/m2/h (Delfin
Technologies, Stamford, Connecticut).
■ Botox injection (50 units per axilla) is very effective but expensive and lasts
only 4 to 6 months.
■ When conservative management has been used for 2 to 3 months and found
wanting, surgical management is justified to both the patient and the insurer.
SURGICAL MANAGEMENT6–9
Preoperative Planning
■ As the offending sweat glands are only associated with the hair-bearing area of
the axilla, this area is outlined in the holding area of the ambulatory.
■ Although it might seem reasonable to consider use of a local anesthesia with
sedation, this is not advised. The potential movement of the patient while using
a powered, rotating instrument blindly in the axilla is very real. A short,
general anesthetic will also expedite the efficiency and ensure the safety of this
60-minute procedure.
■ This is, at the very least, a two-person operation. Though the surgeon and a
scrub nurse will suffice, an additional assistant will significantly aid in
providing the essential maximum lateral tension on the surgical field.
■ Following induction, the hair-bearing area is outlined and shaved. Taking care
to mark a 1-cm access incision within the axillary fold prior, superficially
inject (producing a wheal) about 20 to 30 mL of 0.5 % Xylocaine with 1/200
000 epinephrine within the outlined area (FIG 3).

Positioning
■ In the supine position, the patient’s arms are abducted at about a 100-degree
angle and secured.
■ The surgeon then preps for surgery concurrent with the patient’s prep, hereby
adding to the hemostatic effect of the local anesthetic.
FIG 3 • The hair-bearing area is shaved and injected for
local hemostasis, and the 1-cm access incision in the
anterior axillary line is marked.
T E C H N I Q U E S
■ After draping the axilla, the surgeon takes a place at the head of the table
above the arm board and the abducted arm.
■ The assistants provide maximal lateral tension to the surgical field to
facilitate elevation of the axillary tissue safely and efficiently (TECH FIG
1A).
■ The previously placed anterior axillary fold mark is incised. Using curved
Metzenbaum dissecting scissors, the previously outlined hair-bearing area is
elevated in the most superficial subcutaneous plane possible by leaving fatty
tissue on the elevated flap. This dissection is typically rapid and bloodless.
■ The suction-assisted cartilage shaver, a Stryker CORE Powered Instrument
Driver, is brought on to the surgical field (TECH FIG 1B). This shaver,
commonly used in endoscopic orthopedic cartilage shaving of joints, consists
of two concentric metal cannulas, one smaller than the other. At its tip, the

outer larger cannula has a half-opened portion that protects the sharp, inner,
oscillating cannula, thus allowing continuous curettage and suction drainage
(TECH FIG 1C).
■ With the handpiece setting placed at its lowest setting (900 rpm or less), the
shaving tip is inserted into the previously created subcutaneous tunnel, taking
care to ALWAYS hold the open cannula toward the undersurface of the
elevated flap and keeping the shaver moving.
■ With the flap under maximal tension by the assistants, the shaver is slowly
passed in a systematic, gridlike fashion over the undersurface of the flap,
thereby aspirating the subcutaneous fat and permanently damaging/aspirating
the offending sweat glands (TECH FIG 1D). Care must be taken to keep the
shaver moving to prevent perforation of the flap by the shaver. The hair
follicles are always preserved, as is innervation of the surgical area.
■ At completion of the shaving, the skin is everted to verify total removal of
the subcutaneous tissue and preservation of the axillary skin (TECH FIG
1E).
■ Wound suction and external pressure is obtained with placement of a small-
caliber drain through the incision and an externally applied surgical sponge
(TECH FIG 1F). The skin is closed with simple nylon sutures.

TECH FIG 1 • A. Maximal lateral tension by assistants
greatly facilitates subcutaneous dissection. B. The
Stryker suction-assisted cartilage shaver. C. The
double-lumen cannula that provides continuous
curettage and simultaneous suction. D. Aspiration of
the subcutaneous fat. E. Eversion of the now shaved
axillary tissue reveals the hair follicles devoid of fat
tissue, which is synonymous with ablation of the sweat
glands. F. Secure compression on the flap plus a
small drain helps prevent seroma formation.
PEARLS AND PITFALLS
Diagnosis
■ Most patients present with the same, classic history, and signs and

symptoms.
■ Any positive starch test or VapoMeter reading greater than 100
mL/m2/h is diagnostic of hyperhidrosis.
■ Initially, use nonoperative, conservative approach (anticholinergic).
■ Provide insurer with thorough description of symptoms, failure to
respond to conservative therapy, and a photo of positive axillary starch
test or VapoMeter data.
■ This operation is equally effective when the primary complaint is
offending malodor +/− sweating.
Technique
■ If possible, use two assistants (four hands) to provide lateral traction
on the axilla while elevating and shaving the flap.
■ Keep moving the shaver while exerting gentle upward pressure on the
flap while assistants provide tension.
■ If a perforation of the axillary skin occurs, close it with a fast-
absorbing suture; it heals quite kindly.
■ Using retraction and overhead light, transilluminate the flap to verify a
“clean” shaving that preserves only the bulb of the axillary hair
follicles.
POSTOPERATIVE CARE
■ The external dressing and drain are removed the next day; the permanent
sutures are left in place 5 to 7 days, as dehiscence occurs if removed earlier.
■ There is very little pain associated with the operation.
■ When the dressing is removed, the patient almost always notes total cessation
of sweating, which is permanent in greater than 95% of patients.
■ Patients should limit arm abduction for one week postoperatively and are
typically absent from out-of-home employment about 4 days.
OUTCOMES
■ Over 95% of patients have no recurrence of sweating and are quite pleased.
■ If sweating does recur, it is usually nominal and managed with conservative
methods.
■ There is no compensatory sweating (new appearance of hyperhidrosis in
another area).
COMPLICATIONS
■ There has been one hematoma and one infection in my series. Both responded
to conservative measures.

■ In the very uncommon occurrence of a recurrence of significant symptoms, the
procedure has been repeated without consequence and with a successful
outcome (2×/8 years).
REFERENCES
1. Sato K, Kang WH, Saga KT. Biology of sweat glands and their disorders: I.
Normal sweat gland function. J Am Acad Dermatol. 1989;20(4):537-563.
2. Amir M, Arish A, Weinstein Y, et al. Impairment in quality of life among
patients seeking surgery for hyperhidrosis: preliminary results. Isr J Psychiatry
Relat Sci. 2000;37(1):25-31.
3. Cina CS, Clase CM. The illness intrusiveness rating scale: a measure of
severity in individuals with hyperhidrosis. Qual Life Res. 1999;8(8):693-698.
4. DePaepe K, Houben E, Adam R, et al. Validation of the VapoMeter, a closed
unventilated chamber system to assess transepidermal water loss vs. the open
chamber Tewameter. Skin Res Technol. 2005;11:61-19.
5. Walling HW, Swick BL. Treatment options for hyperhidrosis. J Am Acad
Dermatol. 2011;12(5):285-295.
6. Larson D. Definitive diagnosis and management of axillary hyperhidrosis: the
VapoMeter and suction-assisted arthroscopic shaving. Aesthet Surg J.
2011;31(5):552-559.
7. Bechara FG, Altmeyer P, Sand M, Hoffmann K. Surgical treatment of
hyperhidrosis. Br J Dermatol. 2007;156:398-399.
8. Tung T. Endoscopic shaver with liposuction for treatment of axillary
bromhidrosis. Ann Plast Surg. 2001;46:400-408.
9. Arneja JS, Hayakawa TEJ, Singh GB, et al. Axillary hyperhidrosis: a 5 year
review of treatment efficacy and recurrence rates using a new arthroscopic
shaver technique. Plast Reconstr Surg. 2007;119:562-567.

PART 6
Hand Surgery

(Trang không có chữ)

1
CHAPTER
Section I: Anesthesia and
Emergency Procedures
Anesthesia and Emergency
Procedures
John R. Lien and Kevin C. Chung
DEFINITION
■ Wrist and digital blocks are essential for patient anesthesia in the operating
room and during emergency room procedures.
■ Nerve blocks assist with postoperative pain control.
■ Wide-awake local anesthesia no tourniquet (WALANT) involves local
injection of epinephrine with lidocaine for hemostasis and anesthesia instead of
applying a tourniquet and sedation. This technique is useful for minor hand
procedures as well as tendon surgery.
ANATOMY
■ Median nerve
■ At the distal forearm/wrist, the median nerve lies between the palmaris
longus (PL) and flexor carpi radialis (FCR) tendons (FIG 1).
■ The palmar cutaneous branch (PCB) usually passes subcutaneously between
the FCR and PL tendons.

FIG 1 • Median nerve anatomy at volar wrist.

FIG 2 • Ulnar neurovascular bundle anatomy at volar
wrist.
■ Ulnar nerve
■ At the wrist level, the ulnar nerve is radial and dorsal to the flexor carpi
ulnaris (FCU) tendon (FIG 2).
■ The ulnar artery is adjacent to the radial aspect of the ulnar nerve.
■ The dorsal cutaneous branch (DCB) originates from the ulnar nerve
approximately 5 cm proximal to the ulnar styloid. It crosses from palmar to
dorsal near the styloid process.1
■ Superficial branch of the radial nerve
■ The superficial branch of the radial nerve (SBRN) becomes subcutaneous
approximately 9 cm proximal to the radial styloid.2
■ At the radial styloid, there are two to three branches of the SBRN in the
subcutaneous tissue (FIG 3).
■ Digital nerves

■ Four nerve branches (two palmar, two dorsal) provide sensation to each digit.
■ The common digital nerves bifurcate to the proper digital nerves at the level
of the distal palmar crease.
■ The dorsal digital nerves of the thumb and small finger extend to the tip of
the dorsal digit.
■ The volar digital nerves supply dorsal sensation distal to the proximal
interphalangeal joint in the index, middle, and ring fingers (FIG 4).
FIG 3 • Superficial branch of the radial nerve anatomy
at the radial wrist.
SURGICAL MANAGEMENT
Preoperative Planning

■ Materials
■ Syringe
■ 27-gauge needle
■ Commonly used local anesthetic agents and additives
• Lidocaine is commonly used due to its rapid onset (within 2–5 minutes of
injection) and medium duration of action (2 hours for digital block).3
• Bupivacaine has a slower onset of action (5–10 minutes) but longer duration
of action (12 hours for digital block).3
• Epinephrine additive induces vasoconstriction, which promotes hemostasis,
prolongs duration of anesthesia, and reduces the systemic toxicity of the
local anesthetic agent.
• Sodium bicarbonate 8.4% additive buffers the low pH of lidocaine,
decreasing injection pain.

FIG 4 • Dorsal hand sensory innervation.
Positioning
■ Whether the procedure is in the operating room or emergency department, the
patient should lie comfortably supine to minimize patient movement during the
procedure.
■ Hand table or Mayo stand.
Approach
■ Digital block
■ Volar subcutaneous approach: This is our preferred technique as it only
requires one injection and is shown to be less painful than the transthecal
approach.4
■ Dorsal transmetacarpal approach
■ Transthecal approach
■ Wrist block
■ Median nerve
■ Ulnar nerve
■ Superficial branch of radial nerve
■ WALANT
■ Use 1% lidocaine with 1:100 000 epinephrine
■ Buffer the lidocaine and epinephrine in a 10:1 ratio with 8.4% sodium
bicarbonate
■ Allow adequate time for the vasoconstrictive effect of epinephrine to take
effect (25 minutes).5
■ Volume of injection depends on the site of surgery (FIG 5).6

FIG 5 • Palmar (A) and dorsal (B) hand injection
volumes.
T E C H N I Q U E S
■ Digital Nerve Block
Volar Subcutaneous Block
■ Insert a 27-gauge needle at the distal palmar crease at the level of the A1
pulley (TECH FIG 1).
■ Inject 3 mL of local anesthetic into the subcutaneous tissue. The anesthetic
should cause tumescence and flow of anesthetic solution radial and ulnar to
the flexor tendon sheath (see FIG 5A). If there is significant resistance to
injection, withdraw the needle slightly.
Dorsal Transmetacarpal Block
■ Identify the metacarpal head of the digit of interest.

■ At this level, introduce a 27-gauge needle from the dorsal web space and
advance toward the palm (TECH FIG 2).
TECH FIG 1 • Middle finger volar subcutaneous block.
Note tumescence radial and ulnar to the flexor tendon
sheath in A. Note the needle is in the subcutaneous
tissue superficial to the flexor tendon sheath in B.
TECH FIG 2 • Dorsal transmetacarpal block.

■ Inject 2 mL of local anesthetic into the radial and ulnar web space to
anesthetize each digital nerve. Periodically aspirate the syringe to prevent
intravascular injection.
Transthecal Digital Block
■ Palpate the flexor tendon sheath at the palmar digital crease.
■ Insert a 25-gauge needle through the flexor tendon at this level until contact
with bone.
■ After bone contact, slowly withdraw the needle with gentle pressure on the
syringe (TECH FIG 3).
■ When the needle is withdrawn 1 to 2 mm, anesthetic will enter the sheath.
■ Inject 2 mL of local anesthetic.
TECH FIG 3 • A. Transthecal digital block. B. Cross-
section view.
■ Wrist Block
Median Nerve Block
■ Identify the FCR and PL tendons at the proximal wrist crease.
■ Insert the needle just proximal to the wrist crease and penetrate the flexor
retinaculum (TECH FIG 4).
■ In the absence of PL tendon, insert the needle on the ulnar side of the FCR
tendon.

■ Inject 5 mL of local anesthetic around the nerve.
Ulnar Nerve Block
■ Identify the FCU tendon at the proximal wrist crease.
■ Introduce a 25-gauge needle ulnar and dorsal to the FCU, aiming the needle
radially (TECH FIG 5). From this approach, the ulnar nerve is encountered
first. Avoid pushing the needle too far; the ulnar artery is radial to the nerve.
■ Inject 5 mL of local anesthetic around the ulnar nerve, taking care to
intermittently aspirate.
■ Infiltrate the subcutaneous dorsoulnar wrist with 5 mL of local anesthetic to
anesthetize the dorsal cutaneous branch (DCB) of the ulnar nerve.
TECH FIG 4 • Median nerve block at wrist.
Superficial Branch of Radial Nerve Block
■ Palpate the styloid process of the radius.
■ Insert a 25-gauge needle and inject 5 mL of local anesthetic into the
subcutaneous tissue overlying the first through third dorsal compartments.

TECH FIG 5 • Ulnar nerve block at wrist.
■ WALANT: Trigger Finger Release Example
■ Prepare a mixture of 1% lidocaine and 1:100 000 epinephrine buffered with
8.4% bicarbonate. For trigger finger, we inject a total of 10 cc locally.
■ Warm the local anesthetic solution to body temperature.
■ Distract the patient to look away from the injection site.
■ Use a 27-gauge needle to inject 0.5 mL of the anesthetic perpendicularly
subdermally over the A1 pulley (TECH FIG 6).
TECH FIG 6 • WALANT injection for trigger finger.