(Trang không có chữ)
TECH FIG 2 • A,B. A traumatic injury to the ulnar and
volar thumb can be resurfaced using a FDMA flap.
Prior to reconstruction, the wound should be free of
infection and necrotic tissue. C. Most commonly, the
FDMA flap is designed from the MCP proximally to the
proximal interphalangeal joint distally over the dorsal
index finger. Proximal extensions can be used as
shown here for coverage of larger thumb defects. D.
The FDMA flap can be raised with a dermofascial
pedicle, as shown here, or with an adipofascial
pedicle. The flap pivot point is marked here with an “X”
at the junction of the first and second metacarpal
bases, just distal to the EPL. An incision from the pivot
point to the defect is marked for flap inset; alternately,
the flap could be tunneled into the defect if an
adipofascial pedicle was raised. E. The fascia of the
first DIO is included with the pedicle to prevent injury
to the FDMA and the draining veins of the flap. Here,
the first DIO is shown radial to the flap pedicle,
exposed but not violated. The paratenon is preserved
over the extensor tendons of the index finger, shown
ulnar to the flap pedicle. F. An incision is made from
the flap pivot point to the thumb defect. The flap
mobility is tested; tension-free inset is critical for flap
survival. G. A different patient is shown here. In this
case, the FDMA flap was raised with an adipofascial
pedicle and tunneled into the defect. A wide tunnel is
created to prevent pedicle compression and venous
congestion. H–J. The FDMA flap and its dermofascial
pedicle are inset using sutures. The nail had been
avulsed; a splint was placed into the nail fold. The
FDMA flap donor site was closed with an FTSG. K,L.
For this patient, the flap was tunneled into the defect
over the volar-ulnar thumb and sutured into position.
The flap donor site and additional superficial wounds
over the distal radial index and middle fingers were
closed with FTSGs.
■ Reverse Dorsoradial Homodigital Flap
■ The reverse dorsoradial homodigital flap is harvested from the dorsoradial
side of the thumb metacarpal (see FIG 3).
■ Its arc of rotation permits coverage of distal volar and dorsal thumb defects
and radial defects of the proximal and distal phalanx of the thumb.7 It is most
commonly used for smaller defects over the dorsum of the thumb; the FDMA
flap provides more tissue and is better suited for coverage of larger volar
defects of the thumb.
■ The flap pedicle is the dorsal radial collateral artery, which is a branch of the
radial artery over the dorsoradial hand at the anatomic snuffbox. It passes
under the extensor pollicis brevis (EPB) tendon as it travels from ulnar to
radial. The pedicle is consistent in its course and caliber, traveling distally 1
cm radial to the midline of the dorsal thumb. It communicates with the
palmar vessels at the middle third of the PP, permitting this flap to be used
reliably as a reverse island flap.
■ The course of the dorsal radial artery can be identified using a Doppler US.
It runs from the snuffbox to the middle of the dorsoradial PP. The pivot point
of the flap is over the middle of the dorsoradial PP.
■ Using a template of the defect, the flap is designed over the dorsoradial
thumb metacarpal, centered over the dorsal radial collateral artery.
■ The skin island is incised, starting at its proximal edge. The dorsal radial
collateral artery is identified, and the flap design is adjusted as needed to
ensure it is over the pedicle.
■ The flap is raised above the paratenon of the extensor tendons. The incision
over the distal flap is made through the dermis, but not deeper, to avoid
transection of the pedicle below.
■ The flap is elevated from proximal to distal. The dorsal radial collateral
artery is divided just distal to where it passes under the EPB.
■ A branch of the dorsal sensory branch of the radial nerve runs with the dorsal
radial collateral artery. It is divided proximal to the flap to permit flap
elevation. This sensory nerve branch can be coapted to the distal radial or
ulnar digital nerve of the thumb; however, significant improvement in flap
sensitivity has not been demonstrated.4
■ A skin incision is made from the flap donor site to the defect to permit inset
while minimizing the risk of pedicle compression and venous congestion that
would occur if the flap were tunneled.
■ A lazy S or a zigzag incision is used.
■ Skin flaps are elevated subdermally radially and ulnarly from the flap
donor site to the midpoint of the PP dorsally over the thumb.
■ The pedicle is elevated with the surrounding subcutaneous tissue to ensure
adequate venous outflow; all nearby venous skin branches are included in the
flap elevation. The dorsal radial artery is not skeletonized.
■ The flap is inset into the defect and sutured into place. The skin above the
pedicle is loosely tackled together to prevent compression and left partially
open to heal by secondary intention or covered with an FTSG.
■ The flap donor site is closed primarily for flaps up to 4 cm in width. Larger
donor sites are closed with an FTSG and covered with a bolster dressing.
■ The flap incisions are covered with antibacterial gauze, sterile gauze, and a
well-padded, hand-based thumb spica splint.
■ The splint can be removed in one week and ROM exercises started.
PEARLS AND PITFALLS
Physical
findings
■ The anatomic course of the FDMA and dorsal radial collateral
artery is consistent from the radial artery. Doppler US can be used
as an adjunct during flap design, but it is not mandatory. Injuries to
the dorsal radial hand and wrist preclude the use of these flaps as
the flap pedicles may have been damaged. In these cases, an
alternate flap should be used.
Technique
■ The FDMA flap donor site leaves a visible donor site over the
donor index finger. It can be harvested as an adipofascial flap to
minimize the aesthetic morbidity of the donor site; however, the
reconstruction of the thumb defect is compromised if the FDMA
flap requires an FTSG for coverage. A skin graft on the flap will be
less durable and less sensate.
■ Maintaining the paratenon over the tendons during flap harvest
permits FTSG take at the donor site for an island Moberg flap,
FDMA flap, and reverse dorsoradial homodigital flap. It also
facilitates smooth tendon gliding for the FPL following a Moberg
flap harvest, the EDC and EIP after a FDMA flap, and the EPL and
EPB after a reverse dorsoradial homodigital flap.
Postoperative
■ The most complete and natural sensation for the thumb pulp is
regained using a Moberg flap. Over time, patients will adapt to the
sensory input from the FDMA flap; however, cortical retraining is
often incomplete and the patient continues to feel as though the
dorsal index proximal phalanx is being touched rather than the
pulp of the thumb. The homodigital island flap is not innervated.
Sensation may be partially regained through the ingrowth of
nearby cutaneous nerve fascicles.
Therapy
■ Excessive IP joint flexion, particularly for over 2 weeks, can lead
to a flexion contracture following an FDMA flap. Early ROM
exercises are recommended, as long as flap viability is not
compromised, to minimize IP joint stiffness.
■ Hand therapy can help a patient regain ROM following a thumb
injury. It can also help with desensitization of the reconstructed
thumb and donor site.
FIG 4 • The FDMA flap provides excellent soft tissue
coverage for thumb defects. The donor-site aesthetics
improve with time. Here, the FDMA flap reconstruction
is shown at 2 weeks (A) and 16 months (B,C)
postoperatively.
POSTOPERATIVE CARE
■ Nonabsorbable sutures are removed 2 weeks postoperatively.
■ The dressings are changed and any FTSG bolster dressings are removed 5
days postoperatively.
■ ROM exercises are started 5 to 7 days postoperatively.
■ If there is any concern of flap tension, a thermoplastic splint can be used to
protect the flap for an additional 1 to 2 weeks between ROM exercises and
during sleep.
OUTCOMES
■ The Moberg flap best restores sensation to thumb defects. The reverse
dorsoradial homodigital flap is not innervated and offers the least complete
sensory recovery, averaging 10-mm two-point discrimination.4
■ The Moberg, FDMA, and homodigital flaps restore the thumb pulp contour
well (FIG 4).
■ The Moberg flap has the least donor site morbidity but can be used only for
coverage of smaller thumb defects. The FDMA and homodigital flaps permit
coverage of larger defects; the patient must be counseled preoperatively about
the visible donor sites on the dorsal hand.
COMPLICATIONS
■ Hair growth is rare over the dorsoradial thumb metacarpal. The Moberg and
reverse dorsoradial homodigital flaps provide hairless coverage for thumb
defects. In contrast, the FDMA flap typically contains hair. Laser hair removal
can be used once the flap has healed if hair growth is problematic.
REFERENCES
1. Soucacos PN. Indications and selection for digital amputation and
replantation. J Hand Surg Br. 2001;26(6):572-581.
2. Margalit M, Shulman S, Stuchiner N. Behavior disorders and mental
retardation: the family system perspective. Res Dev Disabil. 1989;10(3):
315-326.
3. Strauch B, Lang A, Ferder M, Keyes-Ford M, et al. The ten test. Plast
Reconstr Surg. 1997;99(4):1074-1078.
4. Moschella F, Cordova A. Reverse homodigital dorsal radial flap of the thumb.
Plast Reconstr Surg. 2006;117(3):920-926.
5. Shah R, Cavale N, Fleming A. A modification of the V-Y Moberg
advancement flap for thumb reconstruction. J Hand Surg Eur Vol.
2007;32(3):357-358.
6. Mutaf M, Temel M, Günal E, Işık D. Island volar advancement flap for
reconstruction of thumb defects. Ann Plast Surg. 2012;68(2):153-157.
7. Hrabowski M, Kloeters O, Germann G. Reverse homodigital dorsoradial flap
for thumb soft tissue reconstruction: surgical technique. J Hand Surg [Am].
2010;35(4):659-662.
47
CHAPTER
Reverse Flow Radial
Forearm Flap
Kate Elzinga and Kevin C. Chung
DEFINITION
■ The most commonly used regional flap for coverage of volar and dorsal hand
and wrist wounds is the reverse radial forearm flap (RRFF). It is a reliable and
versatile flap.
■ The radial forearm flap can be used as an antegrade flap to cover defects of the
elbow.
■ The radial forearm flap can also be harvested as a free flap for distant defects.
■ The RRFF can be designed up to 35 × 15 cm in size, harvesting up to two-
thirds of the circumference of the forearm, from 4 cm distal to the antecubital
fossa to the wrist crease.
■ The RRFF’s large size makes it suitable for coverage of nearly all wrist and
hand wounds. However, the arc of rotation of the flap into the defect typically
precludes harvesting the flap extending to the distal forearm.
■ The flap can be pre-expanded to further increase its dimensions proximally in
the forearm for adequate use as a reverse flap, although this is rarely
necessary.1
ANATOMY
■ The RRFF is a Mathes and Nahai type B flap; it is supplied by septocutaneous
perforators. Its pedicle is the radial artery and its two accompanying vena
comitantes. The radial artery is divided proximally. Retrograde flow occurs
from the ulnar artery through the deep palmar arch into the radial artery to
provide arterial inflow to the flap.
■ The radial artery originates from the brachial artery. It travels under the
brachioradialis (BR) for most of its course. Distally, it is found in the interval
between the BR radially and the flexor carpi radialis (FCR) ulnarly. The radial
artery perforators travel within the septum between the BR and FCR to supply
the overlying fascia and skin (FIG 1).
■ There are 6 to 10 septocutaneous perforators arising from the radial artery 2
cm proximal to the radial styloid.2 A reverse radial artery perforator flap can be
elevated on these perforators to preserve the radial artery for patients without
an intact palmar arch.3,4
■ The cephalic vein can be harvested with the RRFF although it does not play a
role in the venous drainage of reverse flaps. Venous outflow is through the
avalvular oscillating veins.5 In cases of venous congestion, anastomosis of the
cephalic vein within the flap will decompress the venous congestion.
■ The RRFF is designed over the proximal and middle volar forearm.
■ The RRFF can be harvested as a fasciocutaneous, adipofascial, or fascia-only
flap. It may also be raised above the fascia; the subcutaneous tissue and dermis
above the fascia are raised suprafascially.
FIG 1 • The radial artery and its vena comitantes are
found in the distal forearm within the intermuscular
septum between the BR radially and the FCR ulnarly.
The radial border of the RRFF can be centered over the
radial artery as shown here. Alternatively, the flap can
be designed with its radial margin over the radial artery.
The LABC and cephalic vein are optional structures that
can be included in the flap design.
■ The lateral antebrachial cutaneous nerve (LABC) can be harvested with the
flap and coapted to a sensory nerve at the defect site to innervate the flap.
■ Alternatively, the LABC can be left in situ during flap harvest, preserving the
sensation to the radial forearm.6
■ The palmaris longus can be elevated with the flap for use as a vascularized
tendon graft. For example, it can be used for an extensor tendon defect or to
create a flexor pollicis longus during osteoplastic thumb reconstruction with an
iliac crest bone graft and a RRFF.7 The BR can also be included as a
vascularized tendon graft or part of the radius as a vascularized bone graft.8
■ The pivot point for the RRFF is the radial styloid.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ The patient is assessed for suitability for regional flap reconstruction following
a wrist or hand injury.
■ Important history includes the patient’s age, handedness, and occupation and
avocations.
■ The patient’s past medical history, medications, allergies, and social history
are noted. In particular, risk factors for flap loss, poor wound healing, and
additional postoperative complications are discussed.
■ Comorbidities associated with poor wound healing include smoking,
diabetes mellitus, end-stage renal disease, cardiac disease, peripheral
vascular disease, vasculitis, malnutrition, immunosuppression, and
hypercoagulable states.
■ Details of previous trauma or surgeries to the forearm are gathered. History of
any previous radial artery cannulation for invasive blood pressure monitoring
is also important.
■ If there is concern of damage to the radial artery or its perforators,
angiography can be performed to evaluate the vascularity of the arm.
■ The patient’s defect is examined. The size of the wound is measured. Exposed
structures, necrotic tissues, and any signs of infection are documented.
■ Wounds with exposed tendon and bone are best covered using flaps. The radial
forearm flap is a pedicled regional flap that can be safely performed in most
patients. It alleviates the need for a two-stage flap reconstruction such as a
groin flap or microvascular reconstruction with a free flap.
■ The vascularity of the hand must be carefully assessed. If the radial artery is
harvested for the RRFF, the patient must have an intact palmar arch with
arterial inflow from the ulnar artery to prevent hand and finger ischemia.
■ The modified Allen test is used to clinically assess the integrity of the palmar
arch (FIG 2). The examiner compresses the patient’s ulnar and radial arteries
at the volar wrist and then instructs the patient to open and close the hand into
a tight fist until the palm is blanched. The examiner then releases the ulnar
artery and looks for arterial flow from the ulnar artery through the palmar arch
to the radial side of the hand within 6 seconds. The test is repeated to assess
the radial artery.
■ The motor and sensory nerves of the hand and forearm are tested. Any pre-
existing abnormalities are noted.
IMAGING
■ Plain radiographs are performed for patients with traumatic wounds. Any
fractures, foreign bodies, and abnormal joint intervals secondary to
ligamentous injuries are noted.
■ The authors do not routinely perform angiography prior to RRFF harvest. If
the patient has sustained previous trauma to the forearm or has undergone
previous surgery to the forearm, angiography can be used to evaluate the
integrity of the vascular system of the arm and the patency of the radial artery,
ulnar artery, and palmar arch.
■ An ultrasound (US) can be performed to do a Doppler Allen test if the patient
is unable to participate in a clinical Allen test or to confirm clinical findings.9
This is not necessary for most patients.
NONOPERATIVE MANAGEMENT
■ Prior to flap coverage, the wound is debrided to ensure it is clean with no
necrotic tissue.
■ Antimicrobial dressings are used prior to RRFF coverage to minimize the
bacterial load of the wound.
SURGICAL MANAGEMENT
■ The size of the patient’s wound and the presence of exposed bone and tendon
help to guide the selection of an appropriate flap for reconstruction.
■ Local flaps can be used for small defects.
■ Regional flaps, such as the RRFF, are excellent options for moderate- to
large-sized defects of the volar and dorsal hand and fingers.
■ Free flaps are an alternative but require a longer operative time, a distant
donor site, and microsurgical expertise.
Preoperative Planning
■ The risks and benefits of flap reconstruction are discussed in detail with the
patient.
■ The benefits of the RRFF include a supple, durable, and thin flap for
reconstruction. The color match is excellent for dorsal hand defects. In dark-
skinned patients, the color match for volar defects may be poor.
■ The risk of partial or complete flap loss is discussed.
FIG 3 • The RRFF is harvested over the proximal and/or
middle third of the forearm, depending on the required
size and arc of rotation. For RRFFs harvested with a
width over 6 cm, closure with an STSG is required.
■ The patient is counseled about the donor-site defect of the RRFF. The donor
site is visible over the proximal volar forearm.
■ For flaps over 6 cm in width, a split-thickness skin graft (STSG) is typically
used to close the donor site (FIG 3).
■ The appearance of the STSG at the recipient site, the appearance of the
STSG donor site (typically the anterior upper thigh), and the risk of the
STSG failure are explained to the patient.
■ If the LABC is harvested, the patient must be counseled about the sensory loss
he or she will experience over the radial forearm postoperatively. This may
improve with time due to collateral sprouting of adjacent nerves, but full
sensory recovery is unlikely.
■ The most feared complication of RRFF harvest is ischemia of the hand
following division of the radial artery. If this occurs, a vein graft is typically
used to restore the radial artery and thus the arterial inflow of the hand. The
patient is counseled about this rare complication and the need for possible vein
graft harvest, either the cephalic vein or the saphenous vein.
Positioning
■ The patient is positioned supine with the arm supinated on a hand table for
RRFF harvest.
■ A tourniquet is applied over the upper arm.
■ After the flap incisions are designed, the tourniquet is inflated to permit safe
flap elevation in a bloodless field.
■ Once the flap has been elevated with its pedicle, the tourniquet is deflated
and the vascularity of the flap and the hand are assessed. Hemostasis is
achieved prior to flap inset and donor-site closure to minimize the chance of
hematoma and subsequent flap compromise.
Approach
■ The flap is typically designed over the middle third of the volar forearm using
a template of the wound to mark the flap dimensions. The arc of rotation of the
flap is tested to ensure the inset will be tension-free. If the flap must reach
further distally, it can be designed over the proximal third of the forearm.
■ Loupes are worn to facilitate flap elevation.
T E C H N I Q U E S
■ Reverse Flow Radial Forearm Flap
■ The flap can be designed with its radial margin over the radial artery or
centered over the radial artery (TECH FIG 1A–C).
■ When centered over the radial artery, the flap is harvested around the radial
border of the forearm that results in a more visible donor site.
■ The radial artery can be palpated over the volar, radial wrist in the interval
between the FCR and BR tendons, and then followed proximally using a
Doppler US. The course of the radial artery is marked, starting from the
volar, radial wrist to the middle of the antecubital fossa.
■ An incision is designed from the distal margin of the flap skin paddle to the
flap pivot point at the radial styloid. This permits elevation of the pedicle and
rotation of the flap distally into the defect.
■ When designed as a fasciocutaneous flap, the RRFF skin paddle is marked
over the proximal and middle forearm. When used as an adipofascial or
fascial flap, an incision is made over the radial proximal forearm centered
over the radial artery. Thin skin flaps are lifted radially and ulnarly to expose
the adipofascial tissue below.
■ The RRFF is raised from ulnar to radial to the FCR and from radial to ulnar
to the BR.
■ The flap is elevated in either the suprafascial or the subfascial plane,
depending on the tissues required for reconstruction of the defect. For both
flap types, the fascia must be incised and harvested with the flap radially over
the BR and ulnarly over the FCR to include the pedicle (TECH FIG 1D); the
flap cannot be raised entirely in the suprafascial plane.
TECH FIG 1 • A. This patient presented with a first
web space adduction contracture secondary to long-
standing thumb carpometacarpal joint osteoarthritis.
To alleviate the patient’s basilar joint pain and to
restore her first web space, a trapeziectomy was
planned along with pinning of the first metacarpal in
an abducted position and first web space contracture
release with interposition of a RRFF. B. The surgical
incisions are marked. A longitudinal incision was
marked over the first web space, extending from the
dorsal to the volar surface of the hand to permit the
release of the contracted skin, subcutaneous tissues,
and adductor pollicis. The metacarpophalangeal joint
of the thumb was marked as a reference point. The
carpometacarpal joint of the thumb was marked
proximally; this incision was used for the
trapeziectomy. C. An RRFF was designed using a
template of the first web space defect site. A 6 cm
long × 4 cm wide flap was marked over the middle of
the volar forearm, centered over the radial artery. The
radial artery can be palpated distally between the FCR
and BR and followed proximally using a Doppler US.
Its course is marked by the dotted line. The radial
styloid is the flap pivot point. D. The fascia must be
raised over the BR radially and over the FCR ulnarly
to ensure that the radial artery and its vena comitantes
are raised with the flap. The LABC and cephalic vein
can be included in the flap design if desired. E. Prior
to tunneling the flap through a wide subcutaneous
tunnel over the dorsoradial wrist to the first web
space, the arc of rotation of the flap is tested to ensure
the flap reaches the first web space defect without
tension on it or its pedicle. Care is taken to avoid
kinking and compression of the pedicle during inset.
The tendons of the BR and the FCR are visible at the
flap donor site. F. RRFFs less than 6 cm in width can
be closely primarily, as shown here. Wider flap donor
sites are closed with a STSG. In this case, the RRFF
was tunneled distally into the first web space defect.
Alternatively, a skin incision can be used to allow flap
rotation distally. A percutaneous pin is placed to
maintain thumb metacarpal abduction following first
web space contracture release for 4 weeks.
■ Perforators from the radial artery to the overlying fascia and skin are
identified in the lateral intermuscular septum between the BR and the FCR
and are protected. To facilitate the identification of the lateral intermuscular
septum, particularly in the proximal arm, the BR is retracted radially and the
FCR is retracted ulnarly.
■ The paratenon is preserved over all tendons during dissection; this permits
STSG take when a wide flap is harvested. The superficial sensory branch of
the radial nerve is protected throughout.
■ The flap’s proximal margin is incised. The radial artery and its vena
comitantes are identified and ligated. Microclips or sutures can be used.
■ If the LABC is harvested with the flap, it is divided at the proximal flap
margin. If it is left in situ, it is identified and protected throughout the
dissection as flap elevation continues.
■ The dermis of the distal margin of the flap is incised sharply, taking care not
to penetrate into the soft tissues below to prevent injury to the radial artery
and vena comitantes.
■ The skin incision is made from the distal flap margin to the flap pivot point.
The flap is elevated from proximal to distal with its pedicle. The pedicle
includes the radial artery and its vena comitantes as well as the cephalic vein
and LABC when desired.
■ When a fasciocutaneous flap is raised, the RRFF skin is secured to the
underlying fascia using absorbable sutures to prevent shearing of the
cutaneous perforators.
■ Vascular branches from the radial artery to the flexor pollicis longus and to
the radius are divided using microclips and bipolar cautery to permit pedicle
elevation to proceed distally.
■ The flap is inset into the defect site using sutures.
■ The flap can be inset through a wide tunnel (TECH FIG 1E) or using a
skin incision from the flap pivot point at the radial styloid to the defect.
■ Care is taken to avoid kinking or compression of the pedicle and any flap
tension.
■ The RRFF donor site is closed primarily if the flap is adipofascial, fascial, or
a narrow fasciocutaneous flap (TECH FIG 1F). Donor-site skin defects over
6 cm in width are closed with a STSG; a sheet STSG is preferred over a
meshed STSG for improved appearance.
■ The skin incision between the flap donor site to the radial styloid is closed
primarily following pedicle dissection in this area.
■ The flap vascularity is assessed after closure of all incisions. Color, capillary
refill, temperature, and turgor are noted.
FIG 2 • The modified Allen test is used to confirm
retrograde flow into the radial artery from the ulnar
artery across the palmar arch prior to division of the
radial artery for a RRFF. If the palmar arch is not
patent, a reverse radial artery perforator flap or
alternate flap should be used instead.
■ The vascularity of the hand is confirmed, and arterial inflow to all digits is
documented.
■ Antibiotic-impregnated gauze is applied to all incisions and covered with
sterile gauze. The skin paddle of the flap is left visible to facilitate
postoperative flap checks.
■ If used, the STSG is carefully padded to prevent shear and to optimize take.
■ A well-padded forearm splint is applied.
■ The arm is elevated postoperatively to minimize edema.
PEARLS AND PITFALLS
Physical
findings
■ Previous trauma to the volar radial forearm precludes the use of
the RRFF. In these cases, the small perforators to the overlying
fascia and skin may have been injured.
Technique
■ For patients with recurrent or persistent carpal tunnel syndrome,
an adipofascial RRFF can be used to wrap the median nerve.10
Postoperative
■ No anticoagulation is used for pedicled flaps. Prophylactic low
molecular weight heparin injections are given daily to prevent
deep vein thrombosis until the patient is mobilizing well
postoperatively.
■ A Doppler US can be used after flap inset to identify audible
arterial and venous perforators to the skin paddle. The location of
these perforators can be marked with a 6-0 polypropylene suture.
This is not critical for pedicled flaps, but can be a helpful adjunct
for postoperative monitoring.
Therapy
■ Scar massage and desensitization exercises can be started under
the guidance of a hand therapist once the incisions are healed,
approximately 3 weeks postoperatively.
POSTOPERATIVE CARE
■ Flap checks are performed every 2 hours postoperatively. The flap and hand
are assessed. If there is a lack of arterial inflow or venous outflow noted for the
flap, the patient is taken back to the operating room urgently for flap
exploration. A kink in the pedicle, hematoma, or compression from a tight
closure can result in flap compromise.
■ The patient is discharged home on postoperative day 3.
■ The patient returns to the clinic on postoperative day 5 for a wound check and
dressing change. If an STSG was used, its take over the donor site is assessed.
■ Early range-of-motion (ROM) exercises are performed for all uninvolved
joints of the upper extremity. If the flap crosses the wrist, gentle wrist ROM
exercises are initiated on postoperative day 5 to 7 as long as no flap
compromise occurs.
■ For flaps crossing the wrist, a resting wrist splint is worn to maintain the wrist
in neutral alignment to 20 degrees of extension for 2 weeks postoperatively.
The splint is removed multiple times during the day for ROM exercises during
the 2nd postoperative week. After 2 weeks, the splint is weaned.
OUTCOMES
■ The fasciocutaneous RRFF provides excellent resurfacing for palmar defects.
Adipofascial or fascia-only RRFFs with STSG coverage provide a thin
reconstruction for the thinner dorsal skin of the hand; these flaps are less
durable but minimize donor-site morbidity compared to fasciocutaneous
RRFFs.
■ The RRFF can be harvested with the LABC. This is particularly helpful for
thumb reconstruction. The LABC is coapted to a digital nerve of the thumb to
innervate the flap. Static two-point discrimination has been reported as 11 mm
for these patients.7 If the RRFF is used for wrist coverage, the LABC can be
coapted to a branch of the superficial sensory branch of the radial nerve.5
COMPLICATIONS
■ Flap loss is unusual with a pedicled RRFF.
■ If the patient is bothered by the appearance of the RRFF donor site over the
proximal arm following closure with an STSG, serial excision of the STSG can
be performed.
REFERENCES
1. Masser MR. The preexpanded radial free flap. Plast Reconstr Surg.
1990;86(2):295-301.
2. Weinzweig N, Chen L, Chen ZW. The distally based radial forearm
fasciosubcutaneous flap with preservation of the radial artery: an anatomic and
clinical approach. Plast Reconstr Surg. 1994;94(5):675-684.
3. Hansen AJ, Duncan SF, Smith AA, et al. Reverse radial forearm fascial flap
with radial artery preservation. Hand. 2007;2(3):159-163.
4. Ho AM, Chang J. Radial artery perforator flap. J Hand Surg [Am].
2010;35(2):308-311.
5. Chang SM, Hou CL, Zhang F, et al. Distally based radial forearm flap with
preservation of the radial artery: anatomic, experimental, and clinical studies.
Microsurgery. 2003;23(4):328-337.
6. Kaufman MR, Jones NF. The reverse radial forearm flap for soft tissue
reconstruction of the wrist and hand. Tech Hand Up Extrem Surg.
2005;9(1):47-51.
7. Anani RAA-L, El-Sadek AN. Sensate reversed radial forearm flap for
posttraumatic missing thumb reconstruction: long-term results. Egypt J Plast
Reconstr Surg. 2009;33(1):25-30.
8. Cheema SA, Talaat N. Reverse radial artery flap for soft tissue defects of hand
in pediatric age group. J Ayub Med Coll Abbottabad. 2009;21(1):35-38.
9. Habib J, Baetz L, Satiani B. Assessment of collateral circulation to the hand
prior to radial artery harvest. Vasc Med. 2012;17(5):352-361.
10. Luchetti R, Riccio M, Papini Zorli I, Fairplay T. Protective coverage of the
median nerve using fascial, fasciocutaneous or island flaps. Handchir
Mikrochir Plast Chir. 2006;38(5):317-330.
48
CHAPTERUlnar Artery Perforator Flap
Kate Elzinga and Kevin C. Chung
DEFINITION
■ The ulnar artery perforator flap was first described by Becker as a pedicled
flap based on the dorsal branch of the ulnar artery (FIG 1).1 The mobility of
this flap is limited by its short pedicle.
■ The ulnar artery perforator flap can also be designed based on the ascending
branch of the dorsal branch of the ulnar artery, increasing its reach to distal
hand defects (FIG 2).2
■ The ulnar artery perforator flap is most commonly used as a pedicled flap.
Alternatively, it can be harvested as a free flap.
■ A major advantage of perforator flaps is the preservation of the major vessels
of the forearm; the ulnar and radial arteries are not sacrificed.
■ The ulnar artery perforator flap can be used for coverage of defects of the
ulnar hand and wrist, both dorsal and volar, typically up to 10 × 5 cm in size.1
■ Larger flaps, up to 20 × 9 cm, can be harvested, but venous congestion can
result.3
■ Supercharging a larger flap by anastomosing a subcutaneous flap vein to a
nearby vein of the dorsal hand can improve venous outflow.4
■ The flap can be raised as a fasciocutaneous or adipofascial flap.
FIG 1 • The ulnar artery perforator flap is shown here
based on the dorsal branch of the ulnar artery. It can be
used for coverage of defects over the ulnar dorsal and
volar wrist and hand (shaded area).
ANATOMY
■ The hand is supplied by the radial and ulnar arteries that branch from the
brachial artery over the antecubital fossa, 1 cm distal to the elbow joint. The
ulnar artery travels distally beneath the flexor carpi ulnaris (FCU), volar to the
flexor digitorum profundus. Perforators from the ulnar artery travel to the
overlying fascia and skin between the FCU and the flexor digitorum
superficialis. The superficial and deep palmar arches are located in the palm,
formed by the radial and ulnar arteries.
■ Sacrifice of the radial or ulnar artery for flap elevation risks hand ischemia if
the patient does not have an intact palmar arch. Perforator flaps may be safely
used in these cases.
■ The ulnar artery gives off seven ± two perforators to the skin over the ulnar
forearm with a diameter of 0.5 mm or greater.5
■ The pedicle length for propeller or free flaps based on these perforators is 3.3
mm on average, ranging from 2.5 to 4.0 mm.5
■ About 69% of the perforators of the ulnar artery are musculocutaneous,
traveling through the FCU or flexor digitorum superficialis to reach the skin.5
■ The remaining perforators are septocutaneous.
■ The ulnar artery perforator flap can be designed as a propeller flap based on
the dorsal branch of the ulnar artery. It can be harvested up to 15 cm in length,
to the mid-forearm, depending on the location of the perforator.
■ Greater pedicle length can be obtained when the flap is based on the ascending
branch of the dorsal branch of the ulnar artery.
FIG 2 • The ulnar artery perforator flap has a longer
pedicle and a greater arc of rotation when based on the
ascending branch of the dorsal branch of the ulnar
artery. The ascending branch travels proximally to the
medial epicondyle. It supplies the overlying fascia and
skin along its course.
■ The dorsal branch of the ulnar artery arises from the ulnar artery 2 to 5 cm
proximal to the pisiform.6
■ Infrequently, in 2 of 26 cadaver dissections, the dorsal branch arises from the
anterior interosseous artery rather than from the ulnar artery.7
■ The dorsal branch of the ulnar artery has a diameter of 1.0 to 1.3 mm.2 It
travels from the volar distal forearm from radial to ulnar, under the FCU, to
give off three branches:
■ The proximal branch enters the FCU 4 to 6 cm proximal to the pisiform.
■ The distal branch supplies the pisiform. It is called the pisiform artery.
■ The middle branch divides into an ascending and a descending branch over
the dorsoulnar forearm to supply the forearm and hand, respectively. The
ascending branch travels proximally to the medial epicondyle. The
descending branch joins the dorsal carpal arch over the dorsal hand. An ulnar
artery perforator flap can be designed based on the ascending branch of the
dorsal branch of the ulnar artery and its two vena comitantes.2
■ The ulnar artery perforator flap can be designed from the palmaris longus
tendon volarly to the extensor digitorum communis tendon of the fourth finger
dorsally.8
■ The ulnar artery perforator flap is approximately 3 mm thick, providing thin
soft tissue coverage.5
■ The ulnar artery perforator flap is designed along the flap axis between the
medial epicondyle and the pisiform (FIG 3). Proximally, the perforators are
larger and more consistent and primary donor-site closure is easier.
■ When used as a free flap, the ulnar artery perforator flap is typically designed
over the proximal forearm.
■ The dorsal sensory branch of the ulnar nerve passes beneath the FCU 5 to 8
cm proximal to the pisiform to travel to the dorsal forearm. It is protected
during dissection of the dorsal branch of the ulnar artery.
■ Flaps widths up to 6 cm can be closed primarily over the ulnar forearm. Wider
flaps require closure with a split-thickness skin graft (STSG).
■ Bone defects of the small finger metacarpal can be reconstructed by harvesting
vascularized cortical bone of the ulna with the ulnar artery perforator flap.9
■ Bone is harvested from the ulna 10 to 15 cm proximal to the pisiform
between the FCU and extensor carpi ulnaris (FIG 4).
FIG 3 • To design an ulnar artery perforator flap, the
medial epicondyle, pisiform, and FCU are marked.
Next, the axis of the ulnar artery perforator flap is
marked from the medial epicondyle to the pisiform.
Ulnar artery perforators are identified along this line
using a Doppler ultrasound. The flap is designed to
include as mainly audible perforators as possible.
FIG 4 • The ulnar artery perforator flap can be used as
an osteocutaneous flap for reconstruction of bone
defects of the small finger metacarpal. Cortical bone of
the ulna can be harvested in the flap 10 to 15 cm
proximal to the pisiform, between the flexor carpi ulnaris
and the extensor carpi ulnaris. The flap is elevated on
the ascending branch of the dorsal branch of the ulnar
artery.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Important factors from the patient’s history include the patient’s age, sex, hand
dominance, occupation and avocations, past medical history, medications,
allergies, and social history.
■ The timing and mechanism of the patient’s injury are recorded. Traumatic
injuries result from sharp, crush, and burn mechanisms. Oncologic defects
result from sharp tissue resection.
■ The patient’s wound is explored, noting the size of the wound, contamination
and tissue necrosis, and signs of infections.
■ Exposed structures are documented, in particular tendon and bone devoid of
paratenon and periosteum; in these cases, flap coverage is required, graft take
will not occur.
■ Donor sites are assessed during wound reconstruction planning. Forearm local
and regional flap donor sites are examined.
■ Injuries to ulnar forearm preclude the use of the ulnar artery perforator flap.
Ulna fractures often result in damage to the perforators, along with lacerations
and crush injuries.
IMAGING
■ Plain radiographs are used to assess for fractures, dislocations, and foreign
bodies.
■ Angiography is not typically performed unless there are specific concerns of
the patency of the ulnar artery and its perforators.
NONOPERATIVE MANAGEMENT
■ Prior to flap coverage, wound debridement is performed to prepare the wound
bed for closure.
■ Antibacterial dressings can be used prior to flap closure to decrease the
wound’s bacterial load.
SURGICAL MANAGEMENT
■ The pedicled ulnar artery perforator flap is used for closure of ulnar wrist and
hand defects.
■ It has a smaller arc of rotation than does the radial artery forearm flap.
■ It cannot reach the fingers.
FIG 5 • A. An ulnar artery digital perforator flap can be
raised over the ulnar hand. The largest perforators are
found near the metacarpophalangeal joint. B. The flap
can be rotated distally up to 180 degrees to cover
defects of the small finger and volar and dorsal distal
hand.
■ The ulnar artery perforator flap can be raised as a free flap to cover a variety of
defects, including finger injuries. Sizes of 3.5 × 2 cm to 24 × 4 cm have been
reported.5
■ To cover finger injuries, the flap’s arterial pedicle can be anastomosed to the
digital arteries and the vena comitantes can be anastomosed to superficial
dorsal veins of the finger.
■ The medial antebrachial cutaneous (MABC) nerve of the forearm can be
harvested with the flap and coapted to a digital nerve for sensate flap
reconstruction.
■ For injuries of the small finger or distal dorsal or volar hand, an ulnar digital
artery perforator flap can be elevated from the ulnar aspect of the hand and
rotated distally as a propeller flap for closure (FIG 5).
■ Three or four perforators arise over the palmar aspect of the hypothenar
eminence over the abductor digiti minimi from the ulnar artery to supply this
flap.10 The largest perforators are found near the metacarpophalangeal joint.
The flap can be raised as a subfascial or suprafascial flap.
Preoperative Planning
■ The patient is counseled about flap reconstruction using the ulnar artery
perforator flap. Benefits include thin, supple soft tissue coverage. The flap is
durable and reliable.
■ Risks included partial or complete flap loss, wound dehiscence, sensitive
scars, and a visible donor site over the ulnar volar forearm.
■ To permit ulnar artery perforator flap elevation, the dorsal sensory branch of
the ulnar nerve must be divided in some cases. The dorsal sensory branch of
the ulnar nerve branches from the ulnar nerve 5 to 8 cm proximal to the
pisiform.
■ Patients are counseled about the risk of sensory loss over the dorsal ulnar
hand if the nerve is divided during flap elevation.
■ Primary nerve repair should be performed to aid sensory recovery and to
prevent a painful neuroma.
Positioning
■ The patient is positioned supine with the arm out on a hand table.
■ A tourniquet is placed on the upper arm.
Approach
■ Loupes facilitate safe elevation of the flap and pedicle.
■ The ulnar artery can be palpated over the volar ulnar wrist. Ulnar artery
perforators can be identified using a Doppler ultrasound.
■ The flap design is marked to maximize inclusion of audible perforators.
■ Incisions are planned prior to inflation of the tourniquet. The tourniquet is
inflated during flap elevation to permit bloodless dissection. Once the flap and
its pedicle are raised, the tourniquet is deflated to assess the flap’s vascularity.
Hemostasis is achieved prior to flap inset and closure.
T E C H N I Q U E S
■ Ulnar Artery Perforator Flap
■ The medial epicondyle, pisiform, and flexor carpi ulnaris (FCU) are marked.
The axis of the flap is marked from the medial epicondyle to the pisiform,
ulnar to the FCU. The approximate position of the dorsal branch of the ulnar
artery is marked 4 cm proximal to the pisiform, ulnar to the FCU.
■ The ulnar artery is palpated over the distal volar forearm. It is followed
proximally using a Doppler ultrasound to identify and mark perforators of the
ulnar artery on the overlying skin. The largest and most constant perforators
are found over the volar ulnar forearm, at the junction of the proximal and
middle third of the forearm.5 Perforators are also consistently found at the
junction of the middle and distal thirds of the forearm.
■ A template of the defect is used to mark the flap dimensions.
Pedicled Flap
■ The flap is designed over the junction of the proximal and middle thirds of
the forearm, including as many perforators as possible from the ascending
branch of the dorsal branch of the ulnar artery.
■ The flap is incised proximally and elevated from proximal to distal in a
subfascial plane. It can be raised as a fasciocutaneous or adipofascial flap.
■ The skin between the flap and the pivot point is incised using a lazy S-
shaped incision. Thin skins flaps are lifted radially and ulnarly exposing the
subcutaneous tissue below containing the dorsal branch of the ulnar artery
and its accompanying veins. The pedicle is raised with a 4-cm-wide strip of
adipofascial tissue to prevent injury to the pedicle. The flap and pedicle are
raised from proximal to distal until the dorsal branch of the ulnar artery is
seen entering the undersurface of the pedicle. This marks the pivot point of
the flap, 4 cm proximal to the pisiform.11
■ The flap is tunneled into the defect, or a skin bridge is incised between the
flap pivot point and the defect for flap inset.
■ The flap donor site is closed primarily for fasciocutaneous flaps with a width
less than 6 cm or using a STSG if wider. The STSG is typically harvested
from the ipsilateral anterior thigh.
■ Adipofascial flaps require coverage with a STSG after inset. Their donor
sites can be closed primarily.
■ Antibiotic-impregnated gauze and sterile dry gauze are placed over all
incisions. The flap is left uncovered to facilitate.
■ Postoperative flap monitoring. A well-padded splint is applied. Pressure on
the flap is avoided.
Propeller Flap
■ When used as a distally based propeller flap for hand and wrist coverage, the
flap is designed over one dominant perforator from the dorsal branch of the
ulnar artery; including additional perforators can prevent adequate rotation of
the flap.
■ The largest caliber perforator or the most optimally located perforator is
used.
■ Distal perforators facilitate flap rotation distally and thus are often selected
when multiple perforators are available.
■ All perforators are preserved during initial flap dissection. The desired
perforator is selected. All additional perforators are clamped to ensure that
flap vascularity will be maintained based on the main perforator prior their
division.
■ The width of the flap is designed to match that of the defect (TECH FIG
1A).
■ The length of flap is designed so that the distance between the perforator and
the distal edge of the defect matches the distance between the perforator and
the proximal edge of the flap.
■ The skin distal to the flap is incised to confirm the location of the ulnar
artery and its perforators prior to elevation of the flap. The skin is incised
radial to the FCU.
■ The FCU is retracted ulnarly, exposing the ulnar artery and nerve below.
■ The perforators of the ulnar artery are identified and followed to the
overlying skin to confirm that the flap is properly centered over the
perforators.
■ The flap is elevated subfascially from ulnar to radial to the radial border of
FCU.
■ The radial aspect of the flap is then incised.
■ The flap is elevated in a subfascial plane from radial to ulnar to the ulnar
aspect of FCU, where the dorsal branch of the ulnar artery is seen entering
the flap.
■ The basilic vein is typically elevated with the flap. The basilic vein can be
followed 2 or 3 cm proximal to the proximal flap edge and harvested to
permit venous supercharging if poor venous outflow is noted after inset.4
■ The MABC nerve can be elevated with the flap or left in situ. The ulnar
artery and nerve must be protected.
■ The main perforator is skeletonized as necessary to permit adequate rotation
of the flap and to prevent pedicle kinking.12
■ Additional perforators are clamped, and flap vascularity is assessed.
■ If perfusion is maintained, the additional perforators are divided.
■ If not, the additional perforators are maintained to ensure flap viability.
■ The flap is inset into the defect. It can be rotated up to 180 degrees (TECH
FIG 1B,C).
■ If used as a sensory flap, the MABC is coapted to a sensory nerve located
within or adjacent to the defect.
■ The flap donor site is closed primarily for flaps up to 6 cm in width (TECH
FIG 1D) or using a STSG if a wider flap is harvested.
■ A drain can be placed under the flap or the donor site.
■ Antibiotic-impregnated gauze is placed over all incisions and covered with
sterile gauze. The flap is left uncovered to facilitate postoperative flap
monitoring.
■ A well-padded splint is applied to protect the flap and to decrease tension on
the flap.
■ When the flap is used for coverage of palmar defects, the wrist is splinted
in mild flexion to decrease flap tension.
■ When used for dorsal defects, the wrist is splinted in extension.
TECH FIG 1• A. Following debridement of a traumatic
wound, this patient had a 9 × 4 cm defect over the
dorsal ulnar hand with exposed extensor tendons. An
ulnar artery perforator flap was designed as a propeller
flap for coverage. The width of the flap is designed to
match the width of the defect. The length of the flap is
marked so that when the flap is rotated 180 degrees
around the perforator, the proximal edge of the flap will
reach the distal edge of the defect. An umbilical tape,
vessel loop, or surgical sponge can be used to visualize
the arc of rotation of the proximal flap into the distal
defect during flap marking. B. The ulnar artery
perforator flap is elevated. C. The flap can be rotated up
to 180 degrees into the distal defect. D. Here, the donor
site was closed primarily. The flap width was 4 cm.
Flaps widths up to 6 cm can generally be closed with
sutures directly. Wider flaps require closure with an
STSG.
PEARLS AND PITFALLS
Physical
findings
■ A modified Allen test is performed to assess the patency of the
palmar arch. An intact palmar arch is not required for the ulnar
artery perforator flap but provides valuable information about the
arterial supply of the hand.
Technique
■ During ulnar artery perforator flap elevation, the dorsal sensory
branch of the ulnar nerve may require division. In these cases, the
nerve should be repaired using 9-0 nylon suture or fibrin glue.
■ Dissection of the dorsal branch of the ulnar artery to its origin
from the ulnar artery facilitates rotation of the flap up to 180
degrees.8
Postoperative
■ The patient is instructed to keep the hand elevated following flap
coverage. This decreases flap edema, which lessens the risk of
pedicle compression and venous congestion.
Therapy
■ The fingers, wrist, and forearm can be passively mobilized in the
operating room to assess for flap tension with movement.
Immediate range of motion exercises are performed for uninvolved
joints that do not cause strain on the repair with motion.
POSTOPERATIVE CARE
■ The patient is monitored in hospital for signs of flap compromise.
■ Poor arterial inflow or venous congestion should prompt removal of the
dressings, flap assessment, and urgent return to the operating room to assess
for pedicle compromise due to hematoma, kinking, or compression.
■ The patient is discharged on postoperative day 3.
■ The patient returns to clinic 1 week postoperatively for a dressing change.
■ A thermoplastic splint can be worn for an additional week if range of motion
causes tension on the flap.
■ Range of motion exercises are started under the guidance of a hand therapist 1
week postoperatively and advanced weekly.
OUTCOMES
■ The ulnar artery perforator flap provides thin, durable soft issue coverage in a
single-stage operation (FIG 6).
■ Compared to the radial forearm flap, the ulnar artery perforator flap donor site
is less visible on the forearm and the skin paddle contains less hair.
■ The ulnar artery perforator flap provides an excellent color match for dorsal
wrist and hand defects.
■ In dark-skinned patients, the color is not as well matched for palmar defects.
FIG 6 • The ulnar artery perforator flap at 1 (A) and 10
(B) months postoperatively. Supple, durable, thin soft
tissue coverage is provided for defects of the hand. The
donor site heals well with minimal morbidity.
COMPLICATIONS
■ The MABC can be harvested with the flap to restore sensation at the defect
site. The donor-site sensory deficit is minimal because of existing sensory
overlap and subsequent sensory axon in-growth from neighboring nerves to the
denervated skin.13
■ The risk of venous congestion is lower for the ulnar artery perforator flap
compared to reverse flow flaps, such as the reverse radial forearm flap or the
reverse posterior interosseous flap. The ulnar artery perforator flap is a distally
based island flap, not a reverse flow flap.
■ Incisions over the ulnar forearm, wrist, and hand can be sensitive. Scar
massage is recommended once the incisions are healed, starting approximately
3 weeks postoperatively.
REFERENCES
1. Becker C, Gilbert A. [The ulnar flap]. Handchir Mikrochir Plast Chir.
1988;20(4):180-183.
2. Karacalar A, Ozcan M. Use of a subcutaneous pedicle ulnar flap to cover skin
defects around the wrist. J Hand Surg Am. 1998;23(3):551-555.
3. Ignatiadis IA, Mavrogenis AF, Avram AM, et al. Treatment of complex hand
trauma using the distal ulnar and radial artery perforator-based flaps. Injury.
2008;39(suppl 3):S116-S124.
4. Gomez M, Casal D. The turbocharged Becker flap: a simple variation that
allows coverage of most of the dorsum of the hand. Eur J Plast Surg.
2011;34:211-213.
5. Wei Y, Shi X, Yu Y, et al. Vascular anatomy and clinical application of the free
proximal ulnar artery perforator flaps. Plast Reconstr Surg Glob Open.
2014;2(7):e179.
6. Antonopoulos D, Kang NV, Debono R. Our experience with the use of the
dorsal ulnar artery flap in hand and wrist tissue cover. J Hand Surg Br.
1997;22(6):739-744.
7. Bertelli JA, Pagliei A. The neurocutaneous flap based on the dorsal branches
of the ulnar artery and nerve: a new flap for extensive reconstruction of the
hand. Plast Reconstr Surg. 1998;101(6):1537-1543.
8. Khan MM, Yaseen M, Bariar LM, Khan SM. Clinical study of dorsal ulnar
artery flap in hand reconstruction. Indian J Plast Surg. 2009;42(1):52-57.
9. Choupina M, Malheiro E, Guimarães I, et al. Osteofasciocutaneous flap based
on the dorsal ulnar artery: a new option for reconstruction of composite hand
defects. Br J Plast Surg. 2004;57(5):
465-468.
10. Panse N, Sahasrabudhe P. The ulnar digital artery perforator flap: a new flap
for little finger reconstruction: a preliminary report. Indian J Plast Surg.
2010;43:190-194.
11. Unal C, Ozdemir J, Hasdemir M. Clinical application of distal ulnar artery
perforator flap in hand trauma. J Reconstr Microsurg. 2011;27(9):559-565.
12. Karki D, Singh A. The distally-based island ulnar artery perforator flap for
wrist defects. Indian J Plast Surg. 2007;40(1):12-17.
13. Bertelli JA, Kaleli T. Retrograde-flow neurocutaneous island flaps in the
forearm: anatomic basis and clinical results. Plast Reconstr Surg.
1995;95(5):851-859.
49
CHAPTER
Posterior Interosseous
Artery Flap
Kate Elzinga and Kevin C. Chung
DEFINITION
■ The posterior interosseous artery (PIA) flap is a perforator flap used for
coverage of upper extremity defects. Its harvest avoids the sacrifice of a major
artery, such as that of the radial artery during harvest of the radial artery flap.
■ It is available in patients without an intact palmar arterial arch.
■ The PIA flap is typically used as a pedicled flap. It can also be harvested as a
free flap.1
■ The PIA flap is most commonly used as a retrograde regional flap based on the
anteroposterior interosseous artery system to cover defects of the first web
space, dorsal wrist, dorsal and volar hand, and dorsal thumb up to the proximal
interphalangeal joint.
■ The PIA flap can also be used as an antegrade flap for defects of the elbow,
antecubital fossa, and proximal volar forearm.
■ The dimensions of the PIA flap are designed based on the defect size.
■ One case series of 53 patients, from whom two-thirds of the circumference of
the forearm skin was harvested, reported the use of PIA flaps from 5 × 2.5 cm
to 21 × 10 cm in size.2
■ The PIA flap provides a good color match for defects of the forearm, wrist,
and hand, particularly dorsally.
■ In dark-skinned patients, resurfacing of the palmar skin with a PIA flap leads
to a color mismatch.
ANATOMY
■ The PIA flap is classified as a Mathes and Nahai type B flap; it is supplied by
a septocutaneous perforator.
■ Most commonly, the flap is harvested subfascially as a fasciocutaneous island
flap.
■ It can also be harvested with a skin bridge or as an adipofascial flap, which
permits primary closure of the donor site; the subcutaneous tissue and fascia
are harvested; the dermis is preserved at the donor site.3
■ When used as an adipofascial flap, the flap is covered with a split-thickness
skin graft (STSG) after inset.
■ The flap pedicle is composed of the PIA and its two adjacent vena comitantes.
■ Proximally, the artery is 1.2 to 2.1 mm in diameter and the vena comitantes
are 1.0 mm.
■ Over the middle third of the forearm, the PIA has its narrowest caliber,
measuring 0.5 mm.
■ Distally, it measures 0.9 to 1.1 mm.4
■ The PIA arises 4 cm from the lateral epicondyle from the common
interosseous artery in 80% of cases and directly from the ulnar artery in 20% of
cases.5
■ The anterior interosseous artery (AIA) also arises from the common
interosseous artery, or less commonly, directly from the ulnar artery. It runs
along the volar surface of the interosseous membrane (IOM), deep to the flexor
digitorum profundus and flexor pollicis longus.
■ The PIA passes through the IOM from the volar forearm to the dorsal forearm
8 cm distal to the lateral epicondyle and 14.5 cm proximal to the ulnar styloid.5
■ In most cases, it gives origin to three fasciocutaneous perforators to the
overlying skin in the proximal forearm and six to eight perforators in the
distal forearm.4
■ The PIA runs with the posterior interosseous nerve (PIN) along the dorsal
IOM to the hand in the septum between the extensor digiti minimi (EDM)
and extensor carpi ulnaris (ECU).
■ After passing under the supinator in the proximal forearm, the PIA runs over
the abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis,
and extensor indicis proprius (FIG 1).
■ Two centimeters proximal to the distal radioulnar joint (DRUJ), just proximal
and radial to the head of the ulna, a branch of the PIA travels volarly through
the IOM and anastomoses with the dorsal branch of the AIA.
■ This anastomotic connection is the basis for the retrograde PIA flap.
■ The PIA continues distally and joins the dorsal carpal arch. The retrograde PIA
flap also receives some flow through this arch.
■ The axis of the flap is marked from the lateral epicondyle of the elbow to the
head of the ulna.5
■ The flap design is centered on the septum between the EDM and ECU to
maximize the number of perforators entering the flap from the PIA between
the dorsal margins of the ulna and radius (FIG 2).
■ The flap is typically designed up to 18 × 8 cm in size.
■ A segment of the proximal third of the ulna, with a cuff of the extensor pollicis
longus, can be included in the PIA flap for use as an osteocutaneous flap.6
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Important aspects of the patient history include age, sex, handedness,
occupation and avocations, past medical history, medications, allergies,
smoking and recreational drug use, and previous injury to the affected arm.
■ The wound is evaluated for
■ Exposed and damaged structures—skin, tendons, neurovascular structures,
bone
■ Health of remaining structures—tissue necrosis, contamination, signs of
infection
■ Local and regional donor sites
FIG 1 • The course of the posterior interosseous artery
is shown in the dorsal forearm. It originates from the
common interosseous artery, or less commonly, from
the ulnar artery directly. It passes under the supinator
and then travels over the abductor pollicus longus,
extensor pollicis longus, extensor pollicis brevis, and
extensor indicis proprius. Two centimeter proximal to
the DRUJ, a branch of the PIA travels volarly through
the IOM to form an anastomosis with the dorsal branch
of the AIA. The PIA continues distally to contribute to
the dorsal carpal arch. The axis of the flap is marked
from the lateral epicondyle to the head of the ulna to
maximize the capture of PIA perforators into the flap.
■ Radiographic imaging is used in conjunction with physical examination to
determine the presence and extent of bone injuries.
■ Skin and soft tissue defects can be adequately reconstructed using soft tissue
flaps.
■ When the defect size is too large for local flap coverage, the PIA flap is a
useful regional flap that can be performed. It alleviates the need for a
microsurgical free flap from a distant donor site.
■ Many tendon and bony defects can be reconstructed in the hand and then
covered with a PIA flap during the same operation. This fasciocutaneous flap
provides reliable, durable soft tissue coverage of exposed structures and a
smooth gliding surface for underlying tendons.
■ Skin laxity is assessed over the dorsal forearm using a pinch test.
■ Flaps larger than 4 to 6 cm in width typically require donor site closure with
a skin graft.
■ If desired, the skin graft can be excised later using serial excision; the patient
must be appropriately counseled prior to flap reconstruction regarding the
expected appearance of the donor site given its visible location over the dorsal
forearm.
IMAGING
■ Radiographs are performed of the injured extremity to assess for fractures or
foreign bodies.
■ Angiography is not routinely performed prior to PIA flap reconstruction.
■ If there is concern of the integrity of the PIA or AIA-PIA anastomotic arch,
angiography can be considered to evaluate the vessels or a different flap can
be selected.
FIG 2 • The PIA perforators run in the interval between
the EDM and ECU to supply the overlying skin. The AIA
runs volar to the IOM in the forearm. Distally, 2 cm
proximal to the DRUJ, the AIA gives off a dorsal branch
that forms an anastomosis with the PIA.
NONOPERATIVE MANAGEMENT
■ The wound must be adequately debrided and cleansed prior to flap
reconstruction. Following traumatic injury, the wound is explored, injured
structures are assessed, and necrotic tissue is debrided. Once the wound is
clean and the tissues have demarcated, flap reconstruction can proceed.
■ For the reconstruction of oncologic defects, final tumor pathology and
negative margins are established prior to flap closure.
■ Moist, antibacterial dressings can be used in the interim to minimize tissue
desiccation and bacterial load.
SURGICAL MANAGEMENT
■ Local flaps are limited to coverage of small defects of the upper extremity.
■ Larger regional flaps, such as the PIA flap, provide coverage of forearm, wrist,
and hand defects without the need for free flap microsurgical reconstruction
(FIG 3).
■ Compared with free flaps, pedicled flaps require less general anesthesia time,
avoid the need for flap harvest from an uninjured limb or the trunk, and are
options when microsurgical equipment or expertise is unavailable.
FIG 3 • This patient underwent a ray resection of the
thumb for treatment of squamous cell carcinoma. In-
transit metastases were resected from the volar radial
forearm. Following pathological confirmation of negative
margins at both locations, a PIA flap was used for
coverage of the exposed trapezium at the base of the
radial hand wound. (Courtesy of Steven Haase, MD.)
Preoperative Planning
■ The risks and benefits of flap reconstruction with a PIA flap are reviewed with
the patient.
■ The benefits include provision of durable, supple soft tissue coverage, a
donor site limited to the affected upper extremity, and a single-stage
procedure.
■ The risks include partial or complete flap failure and injury to the PIN. The
patient is counseled that the PIA flap has a visible donor site.
■ When used as a retrograde flap, the PIA flap is insensate.
■ For antegrade or free PIA flaps, the posterior antebrachial cutaneous nerve of
the forearm can be included for sensory restoration.
■ Previous injury to the PIA flap donor site is a contraindication to its use.
■ The PIA perforators are small and thin-walled, so crush or shear injury to
dorsal forearm makes flap harvest unreliable.
■ Injury to the DRUJ and possible damage to the AIA-PIA anastomosis
precludes retrograde PIA flap use.
■ Some authors have reported the absence of the AIA-PIA anastomosis or a
hypoplastic or absent PIA in the middle third of the forearm. Penteado reported
5 such cases in 110 cadavers, Angrigiani reported 1 case in 80 patients, and
Buchler reported 2 cases in 36 patients.7–9
■ Anatomic dissections have confirmed the reliability of the AIA-PIA system
and presence of the PIA throughout the dorsal forearm.5,7 Studies have noted
that the PIA is more superficial and narrowest in caliber over the dorsal third
of the forearm, measuring 0.5 mm.
■ If there are doubts of the integrity of the PIA, the incision can be closed and
another flap can be used.
■ In rare cases, if the PIA is absent or hypoplastic, the AIA is dominant and an
AIA perforator flap can be harvested instead.10,11
Positioning
■ The patient is positioned supine with the arm out on a hand table.
■ A tourniquet is placed on the upper arm of the affected limb.
■ If the PIA flap is harvested with a width over 4 to 6 cm, closure with a skin
graft is typically required. Most commonly, the patient’s ipsilateral thigh is
used for STSG harvest.
Approach
■ Loupes are worn for flap harvest and inset. An operating microscope is not
routinely required; in rare cases, it may be employed if there is difficulty
visualizing the vascular anatomy or concern of pedicle injury during flap
harvest.
■ The flap incisions are designed, most commonly as a longitudinal ellipse.
■ The arm is then elevated and the tourniquet is inflated.
■ Exsanguination with an Esmarch bandage is avoided to maintain visibility of
the PIA and its perforators.
T E C H N I Q U E S
■ The axis of the flap is marked with the forearm in full pronation from the
lateral epicondyle to the ulnar head. This marks the course of the PIA.
■ A Doppler ultrasound is used to identify perforators running along this axis
to the overlying skin. Typically, there is a large perforator found at the
midpoint of the dorsal forearm, along the flap axis. The skin flap is designed
to include this perforator and as many additional perforators as possible.
■ To raise a fascia-only flap, the dorsal forearm fascia is exposed by incising
the skin above the flap and elevating thin dermal flaps bilaterally.
■ To raise a fasciocutaneous flap, the skin, subcutaneous tissue, and fascia are
raised en bloc. Once elevated, it is recommended that the dermis is sutured to
the underlying fascia using absorbable sutures to prevent shearing of the
perforators to the skin.
■ Retrograde PIA Flap
■ The pivot point of the flap is marked 2 cm proximal to the DRUJ, proximal
to the edge of the extensor retinaculum, at the site of the AIA-PIA
anastomosis (TECH FIG 1A).
■ The rotation of the flap into the defect is tested using a sponge, umbilical
tape, or vessel loop.
■ The flap is typically designed at the junction of the proximal and middle
thirds or over the middle third of the dorsal forearm to include the skin
perforators arising distal to the supinator while permitting tension-free
rotation into the distal defect of the wrist, hand, or first web space (TECH
FIG 1B).
■ The proximal flap limit is marked 3 cm distal to the lateral epicondyle.
Proximally, there are no PIA perforators to the overlying skin.12
TECH FIG 1 • A. The axis of the PIA flap runs from the
lateral epicondyle to the head of the ulna. The
retrograde PIA flap is centered over the junction of the
proximal and middle thirds of the forearm or over the
middle third of the forearm based on the arc of rotation
required to reach the defect. The flap pivot point is
marked 2 cm proximal to the DRUJ. A large perforator
is typically found near the midpoint of the dorsal
forearm from the PIA to the overlying skin. The
proximal flap limit is marked 3 cm distal to the lateral
epicondyle. B. The flap axis is marked from the lateral
epicondyle to the ulnar head with the forearm in full
pronation. The pivot point is marked 2 cm proximal to
the DRUJ. A Doppler ultrasound is used to mark skin
perforators. The flap is designed as an ellipse over the
proximal and middle thirds of the forearm to include
audible skin perforators. The flap can be elevated as
an island flap or with a skin bridge as shown here. The
skin bridge overlies the pedicle and is elevated by
incising a 1-cm strip of dermis (marked here in solid
lines). An additional 0.75 cm of subcutaneous fat and
fascia is included on either side of the dermis to
protect the PIA and its vena comitantes (marked here
with dotted lines). An incision is marked from the flap
pivot point to the defect for inset of the flap (marked
here with a solid line from the pivot point in a radial
oblique direction to the thumb defect).
■ A template of the defect is made using Telfa and used to mark the
appropriate flap dimensions, up to 18 × 8 cm in size.
■ The interval between the fifth and sixth extensor compartments can be
palpated; the PIA is found in the septum between the EDM and ECU.
■ The flap is centered over this interval.
■ The flap can be elevated as an island flap, or with a 1-cm skin bridge that
can be closed primarily.
■ The skin bridge protects the pedicle, prevents kinking of the vessels on
inset, and makes flap harvest safer.
Retrograde PIA Island Flap Harvest
■ To raise the flap as an island flap, dissection is typically started distally by
incising through the skin and subcutaneous tissue and identifying the PIA in
the septum between the fifth and sixth extensor compartments (TECH FIG
2A).
■ The pedicle can be followed proximally to the distal edge of the flap. The
flap markings are adjusted if needed to ensure that the flap is centered over
the pedicle.
■ This is a most reliable way to ensure that the flap has been properly
designed prior to elevation.
■ The flap is raised subfascially from its ulnar border to the intermuscular
septum (IMS) between the EDM and ECU (TECH FIG 2B).
■ Next, elevation proceeds from the radial border of the flap, again toward the
IMS between the EDM and ECU.
■ Distal to the supinator, the PIN gives a branch to the ECU that crosses
superficial to the PIA (TECH FIG 2C). The PIA is divided just distal to this
nerve branch.
■ Flap elevation proceeds from proximal to distal. The PIN runs with the PIA
along the dorsal forearm and is protected throughout flap elevation.
■ The pedicle is raised as a fascial strip between EDM and ECU containing the
PIA and its vena comitantes.
■ The PIA gives off multiple braches to the surrounding musculature; these are
divided using microclips and bipolar cautery.
Retrograde PIA Flap Harvest With a Skin Bridge
■ To raise a flap with a skin bridge, the flap is elevated first from its ulnar
border in a subfascial plane toward the IMS between the EDM and ECU.
■ Gentle proximal traction on the muscle bellies confirms the anatomy;
traction on the EDM will extend the small finger while traction on the ECU
will extend the wrist.
TECH FIG 2 • A. To confirm the flap is properly
centered over the PIA, dissection starts distally. The
PIA is identified in the interval between the EDM and
ECU over the dorsal wrist. The flap design is
confirmed over the proximal-middle forearm to ensure
the PIA will be centered within it and then the flap is
elevated. B. The PIA flap is raised subfascially, here
shown from ulnar to radial. Perforators can be seen
entering the flap in the interval between the EDM and
ECU from the PIA below. C. The PIN gives a motor
branch to the ECU distal to the supinator (shown here
on top of the blue background material). This branch
crosses superficial to the PIA. It is protected. The PIA
and its vena comitantes are divided just distal to this
nerve branch and then the flap is elevated from
proximal to distal for retrograde use.
■ Next, the radial border of the flap is raised toward the IMS between the
EDM and ECU. The IMS between the extensor digitorum communis (EDC)
and EDM will be encountered. The EDM is much smaller in size compared
to the EDC that is found one interval radially. To elevate the flap subfascially
above the EDC, the flap fascia is divided from the IMS between the EDC and
EDM.
■ Proximal retraction of the EDM radially and the ECU ulnarly with a self-
retaining retractor facilitates exposure of the PIA (TECH FIG 3A,B).
■ The skin bridge is incised from proximal to distal, a few centimeters at a
time.
■ The pedicle location is confirmed sequentially.
■ The course of the skin bridge can be modified if needed to ensure the
pedicle is maintained within it.
■ A 1-cm dermal bridge is used. An additional 0.75 cm cuff of subcutaneous
fat and fascia is harvested on each side of the skin bridge to protect the
pedicle.
• Restricting the width of the dermis elevation to 1 cm facilitates primary
closure of this area.
■ Distally, the pedicle is closely associated with the periosteum of the ulna.
Ulnar retraction of the ECU tendon exposes the PIA (TECH FIG 3C).
Retrograde PIA Flap Inset
■ Once flap elevation has reached the pivot point, 2 cm proximal to the DRUJ,
dissection stops.
■ The tourniquet is deflated and flap color, capillary refill, temperature, and
turgor are assessed.
■ Arterial bleeding is noted from the flap edges.
TECH FIG 3 • A. Radial retraction of the EDM and
ulnar retraction of the ECU proximally facilitates
exposure of the PIA and PIN in the septum between
these muscles. B. The PIA and its vena comitantes
are shown running centrally on the undersurface of
the flap. The PIN is protected and left in situ between