DISTALLY BASED RADIAL FOREARM FLAP WITHPRESERVATION OF THE RADIAL ARTERY: ANATOMIC,EXPERIMENTAL, AND CLINICAL STUDIES

SHI-MIN CHANG, M.D., Ph.D.,1,2* CHUN-LIN HOU, M.D.,2

FENG ZHANG, M.D., Ph.D.,3 WILLIAM C. LINEAWEAVER, M.D.,3

ZHONG-WEI CHEN, M.D.,4 AND YU-DONG GU, M.D.1

In this article we report on the anatomical, experimental, andclinical investigations of the distally adipofascial pedicledradial forearm flap based on the small perforators around theradial styloid process. There are about 10 small perforators(0.3�0.5 mm in diameter) from the distal radial artery aroundthe radial styloid process. The longitudinal chain-linked vas-cular plexuses (suprafascial, paraneural, and perivenous)formed by the forearm ascending and descending branchesof septofasciocutaneous perforators meet and cross overwith the transverse carpal vascular plexuses around the ra-dial styloid region. Based on these directional-orientedplexuses, distally based adipofascial pedicled radial forearmfasciocutaneous and adipofascial flaps were designed andsuccessfully applied in 34 clinical cases. The pivot point waslocated at 1�2 cm above the radial styloid. The skin island

plus adipofascial pedicle measured between 9�18 cm inlength, with the adipofascial pedicle 3�4 cm in width. Thelength-to-width ratio is 3�5:1. The venous drainage of thisdistally based flap was investigated anatomically and ex-perimentally. The cephalic vein has no positive role for ve-nous drainage in distally based flaps. The difference betweendistally based flaps and reverse-flow flaps, clinical selectionof fasciocutaneous and adipofascial flaps, advantages anddisadvantages, and technical tips for operative success arediscussed.

ª 2003 Wiley-Liss, Inc.

MICROSURGERY 23:328–337 2003

Microsurgical transfer of radial forearm flaps was firstdescribed by Yang et al.1 in Shenyang in 1981, and Songet al.2 in Beijing in 1982. Since then, numerous variantsof radial forearm flap incorporating the radial arteryand its venae comitantes have been designed. The re-verse transposition of the reverse-flow radial forearmisland flap, based on a distal vascular pedicle consistingof the radial artery and its venae comitantes for handreconstruction, was first reported by Lu et al.3 in Xi’anin 1982. This reverse pedicled flap, which consists of

thin, pliable, good-quality skin with a robust bloodsupply, offers a safe, simple, and effective one-stageprocedure for hand reconstruction providing. Further-more, both donor and recipient sites are located withinthe same operative field. However, the two major dis-advantages of the donor site restrict its clinical appli-cations: 1) sacrificing a major artery may jeopardizehand viability, and 2) a displeasing scar deformity mayresult if split-skin grafts are used for closure.

A new distally based radial forearm flap, based onthe tiny perforators of the radial artery around the ra-dial styloid process and longitudinal chain-linked vas-cular plexuses, was invented by our group.4 This flapcan be used as an island fasciocutaneous flap or as aturnover adipofascial flap. In this article, we present theresults of anatomic, experimental, and clinical studies.

MATERIALS AND METHODS

Anatomic Study

An anatomic investigation of the vascular basis ofdistally based radial forearm fasciocutaneous flaps withpreservation of the radial artery and its accompanyingvenae comitantes was conducted in 20 fresh forearms. Acannula was introduced into the radial artery at the

1Department of Hand Surgery, Huashan Hospital, Fudan University, Shang-hai, People’s Republic of China

2Department of Orthopedic and Reconstructive Surgery, ChangzhengHospital, Shanghai, People’s Republic of China

3Division of Plastic Surgery, University of Mississippi Medical Center,Jackson, MS

4Department of Orthopedic Surgery, Zhongshan Hospital, Shanghai,People’s Republic of China

Grant sponsor: China Postdoctoral Science Foundation; Grant number:2002031176.

*Correspondence to: Shi-Min Chang, M.D., Ph.D., Department of HandSurgery, Huashan Hospital Fudan University, Shanghai 200040, People’sRepublic of China. E-mail: shiminchang@yahoo.com.cn

Received 25 May 2003; Accepted 19 June 2003

Published online in Wiley InterScience (www.interscience.wiley.com). DOI:10.1002/micr.10155

ª 2003 Wiley-Liss, Inc.

elbow. The arterial tree was first irrigated with saline toflush out all blood. Then 10 specimens were manuallyinjected with red ABS and ether solution (50 cc) to showthe small arteries. Another 10 specimens were injectedwith 50 cc of China ink mixed with ether to show thevascular plexuses. The specimens were stored in a re-frigerator for 2 weeks to allow for the ether to evapo-rate. Systemic dissection of the forearm was thenperformed using loupe magnification (·4) to investigatethe contribution of the distal perforating vessels aroundthe radial styloid process to the forearm fasciocutaneousplexuses.

Experimental Study

The venous drainage in a distally based radial fore-arm fasciocutaneous flap, especially the role of the largesubcutaneous cephalic vein, was studied. An experi-mental investigation was carried out in five mongreldogs weighing between 12�15 kg. After anesthesia withintravenous pentobarbital 25 mg/kg, a venous tourni-quet was applied to the upper forelimb to delineate thelocation and direction of the cephalic vein. A fasciocu-taneous island flap, 2 · 8 cm in size and centralized overthe cephalic vein, was designed in both forelimbs belowthe elbow. Under pneumatic tourniquet control, the flapwas elevated in the subfascial plane in a proximal todistal manner. The pedicle of the flap was veno-adipo-fascial. In the proximal end of the flap, the cephalic veinwas dissected and ligated. The pneumatic tourniquetwas then removed. Ten minutes later, a needle withheparin connected to a transducer in the other tip wasplaced into the proximal end of the cephalic vein torecord venous pressure.

Ten flaps were randomly divided into two groups. Ingroup 1 (n = 5), the cephalic vein was dissected andligated at 1 cm distal to the base of the adipofascialpedicle. In group 2 (n = 5), the cephalic vein was notligated. The dissection and ligation were done carefullyto avoid damaging the tiny vessels around the cephalicvein. After a silicon sheet was inserted, all flaps weresutured back. The survival area of flap was examinedand measured by planimetry at 2 weeks postoperatively.

Clinical Applications

From 1989�2002, this flap was used in 34 cases ofhand reconstruction (Table 1). There were 27 males and7 females, with an average age of 34.2 years (range,14�54 years old). The injuries included trauma in 19cases, electric burns in 4 cases, and scar contracture in11 cases. The locations of injuries were the volar aspectof the wrist and palm in 15 cases, thumb-index space in10 cases, and dorsal aspect in 9 cases. Nineteen islandfasciocutaneous flaps and 15 turnover adipofascial flapswere performed. The length of the flap (skin island plusadipofascial pedicle) ranged from 9�18 cm, with theadipofascial pedicle 3�4 cm in width and 3�5 cm inlength. The flap length-to-pedicle width is 3�5:1.

Operative Technique

The patient is placed in supine position and with atourniquet on the upper arm. A longitudinal line drawnalong the radial artery in the forearm represents the axisof the flap. The pivot point of the pedicle is about 1�2cm above the radial styloid process. No Doppler ex-amination is applied. The distance between the pivotpoint to the distal margin of the defect plus another 2 cmis drawn retrogradely in the forearm to obtain the flaplength (skin island plus adipofascial pedicle). The skinisland size and location depend on the defect size andlocation on the hand. Usually, the lateral antebrachialcutaneous nerve is included in the flap, and if the flap iswider, the cephalic vein and superficial radial nerve arealso incorporated. The skin incision begins from theproximal margin of the flap and continues straight downto the deep fascia. The cephalic vein is ligated and di-vided at the proximal end. Then the fasciocutaneousisland flap is elevated from proximal to distal from thesubfascial space, along with the cephalic vein, leavingthe deep radial artery intact. Some stitches are made tohold the deep fascia and skin island together tempo-rarily, avoiding any departure between them. Then theskin over the adipofasical pedicle is incised with an S-shape to the subdermal. It is divided 2 cm bilaterally.The adipofascial pedicle (3�4 cm wide) is elevated with

Table 1. Clinical Data of Distally Based Radial Forearm Flaps Without Radial Artery

Recipient site

Flap type No. of cases Location (n) Etiology (n) Results

Island fasciocutaneous flap 19 Volar carpal (7) Trauma (9)Thumb-index space (10) Electric burns (4)4 Survived completelyVolar parmal (2) Scar contracture (6)

Adipofascial flap 15 Volar carpal (6) Trauma (10)Dorsal hand (9) Scar contracture (5)

Distally Based Radial Forearm Flap 329

the skin island flap. There is no need to identify thesmall perforators around the radial styloid process inorder to avoid damage. The skin between the donor andrecipient sites is incised open for flap transposition. Nosubcutaneous tunnel is used to avoid pedicle compres-sion. Then the flap is rotated 90�180� if it is islandfasciocutaneous, or turnover 180� if it is adipofascial. Ifthe skin island is narrower than 3�4 cm (7 cases), thedonor site can be closed directly; otherwise, asplit-thickness skin graft is used. The recipient site of theadipofascial flaps is covered in one stage with a split-thickness skin graft by tied-up suture. The flap canpotentially provide protective sensation if its cutaneousnerve is coapted to the recipient nerve. In 5 cases offasciocutaneous flaps for thenar and first web spacereconstruction, the lateral antebrachial cutaneous nerveis neurorrhaphied with a branch of the superficial radialnerve under an operating microscope at the dorsal wrist.Short-arm plaster of Paris splints are applied for 10�14days. The surgical technique is schematically shown inFigure 1.

RESULTS

Anatomic Study

The distal part of the radial artery is located in theseptum between the brachioradialis tendon and theflexor carpi radialis tendon, and gives many smallperforators that pass through the septum, i.e., septo-fasciocutaneous perforators. There are about 10 smallbranches (0.3�0.5 mm in diameter) 1.5 cm above theradial styloid process, and 1�3 recurrent branches in theproximal part of the superficial (usually 1) and profun-dal (usually 2) radial artery branches (Fig. 2). Theseseptofasciocutaneous perforators pass between the sep-tum, and then fan out at both surfaces of the deep fasciato form a minor subfascial plexus and a rich suprafascialplexus, which give branches to the subcutaneous adipose

tissue to form another abundant vascular plexus. Thevascular plexus sends branches to the cutaneous tissueto form a dense subdermal vascular plexus and nourishthe overlying skin. In the subcutaneous, these perfora-tors also send branches to the superficial sensory nerveand subcutaneous veins to form a paraneural plexus andperivenous plexus to nourish them.

Because the radial artery in the forearm runslengthwise along the extremity, the perforators it issuesare primarily disposed in longitudinal rows. Adjacentperforators are tightly linked up with each other by theirascending and descending branches among differentlayers of the integument tissue. Therefore, the vascularplexuses of the deep fascia and those in the subcutane-ous tissue, the superficial nerve, and the cutaneous vein,coordinately have clear directional components (Fig. 3).

Overall, these vascular plexuses are all arrangedlongitudinally along the courses of their attachmenttissues, i.e., the main vascular axis, the intermuscularseptum, the fiber of the deep fascia, the superficialsensory nerve, and the subcutaneous vein. The radial

Figure 1. Elevation of radial forearm island fasciocutaneous flap with

adipofasical pedicle. Pivot point is 1�2 cm above radial styloid

process. Pedicle is usually 3�4 cm wide. Skin extension to adipo-

fascial pedicle makes it easier to direct closure after rotation.

Figure 2. A: Fresh cadaver forearm injected with red ABS to show

small perforating arteries from forearm. B: There are about 10 small

perforators from distal radial artery and its superficial and deep

branches around radial styloid process.

330 Chang et al.

longitudinal vascular plexus meets the transverse carpalvascular network, and crosses over at the region of theradial styloid process. If a distally based fasciocutaneousflap raised with a pedicle originates in this area, one cansee with the naked eye that in the pedicle there aremultiple longitudinally disposed arterioles. In fact, theflap’s survival territory is made up of a series of inter-linking anatomical territories of small individual per-forators that align one after another to form a chain ofvessels along the long axis of the flap.

A well-developed venous plexus accompanies thearterial circulation. The venous system of the deep fasciadrains the venous blood to the profundal venae comi-tantes through the concomitant perforating veins di-rectly (Fig. 4).

Experimental Study

After release of the pneumatic tourniquet in theforelimb of the dog, the cephalic vein was dilated withthe continuous blood filling it from its distal end (Fig.5). The tightness of the venous wall became stronger andstronger with time. In some flaps, arterial pulsationcould be seen on the cephalic vein, possibly transcon-ducted through the open arterial-venous shunts in thepaw. All flaps became congested and dark. The retro-grade venous pressure ranged from 35�42 mmHg,which is much higher than the normal arterial capillarypressure (30 mmHg in the dog). In group 1, the averagearea of flap survival was 15.6 ± 0.55 cm2 (97.5% of itsoriginal area). In group 2, average survival area was 11.6± 2.07 cm2 (72.5% of its original area). A paired Stu-dent’s t-test showed a statistically significant differencebetween the two groups (P< 0.05). The large superficial

subcutaneous vein (the cephalic) has no positive role forflap survival, because it cannot help venous drainage byreverse-flow through valves, but conducts venous bloodfrom the hand to the flap to cause congestion andswelling, which is hazardous to flap viability.

Clinical Application

Following flap elevation and removing of tourni-quet, robust blood perfusion was seen throughout theentire flap in most cases, as there was active oozing ofblood from the tip of the flap. In 5 cases, the cephalicvein showed an apparent negative effect during theoperation; they were all carefully dissected and ligateddistal to the adipofascial base.

Figure 3. Fresh cadaver forearm injected with China ink to show

vascular plexuses. Perforators from radial artery in forearm form rich

vascular plexuses on suprafascial surface as well as around super-

ficial subcutaneous nerve and vein. Chain-linked plexuses of forearm

have clear longitudinal component.

Figure 4. Venous blood of distally based radial forearm fasciocuta-

neous flap is drained by partner perforating veins or communicating

veins to deep radial venae comitantes directly.

Figure 5. Experimental study of role of large subcutaneous vein in

distally based fasciocutaneous flap in dog. After tourniquet was re-

moved, cephalic vein became dilated and congested due to contin-

uous blood filling from its distal continuity. Cephalic vein was then

ligated at its distal adipofascial pedicle. Flap survived without com-

plication.

Distally Based Radial Forearm Flap 331

Skin flaps survived in all 17 cases of fasciocutaneousflaps. Minor flap loss (<10%) was strictly limited to thedistalmost portion of the remaining 2 flaps, which nee-ded no further surgical treatment. There were no com-plications of split-skin grafts on the adipofascial flap. Inthe donor area, healing was primary except for narrowmarginal edges in some cases. Secondary healing wasuneventful, without problems.

The functional results of the hand were related to theextent of the original injury as well as the patient’scompliance with occupational therapy. Five sensateflaps achieved 10�15-mm static two-point discrimina-tion in a 1-year follow-up.

CASE REPORTS

Case 1

A 27-year-old man suffered from a crush injury onthe right hand, which was caused by an industrial acci-dent. The injury resulted in complicated fractures and asevere trauma to the radial part of the palmer arteryarch. The skin and index, middle, and distal part of thethumb were necrosed in the following days. After de-bridement, the first web space with bone and jointexposure was left uncovered. A distally adipofascialpedicled island fasciocutaneous flap based 1 cm abovethe radial styloid process was successfully transferred tocover the defect. The flap was 13 cm long (including a4-cm adipofascial pedicle), with a pedicle width of 3 cm(L:W ratio, 4.3:1). The skin island was 9 · 4 cm. Thecentral part of the forearm donor site was not able to beclosed directly, and was resurfaced with a split-skingraft. The wound healed uneventfully (Fig. 6).

Case 2

A 28-year-old woman was hospitalized with her rightwrist crushed 1 year earlier. There was severe scar for-mation and contraction. After scar resection, tendondeadhesion, and median nerve decompression, a distallybased adipofasical flap with sufficient subcutaneous fatwas elevated. The flap measured 12 · 4 cm. Turnovertransposition was used to provide soft pad coverage forthe nerve and tendons. The flap was then covered with afull-thickness skin graft. The donor subdermal flap wasrepositioned and sutured directly. Both the donor andrecipient sites healed without any complications (Fig. 7).

DISCUSSION

Soft-tissue reconstruction of the hand, especiallywhen deep vital structures such as bone, joint, or tendon

Figure 6. Case 1. Distally based radial forearm island fasciocuta-

neous flap used for reconstruction of first web space. A: Flap design.

Note skin bridge extension to adipofascial pedicle. B: Flap inset.

Pedicle was directly sutured with aid of skin bridge. C: Postoperative

flap survival.

332 Chang et al.

are exposed, remains a challenge for the plastic and re-constructive surgeon. The choice lies between using adistant flap pedicled on the trunk or the contralateralarm, a microsurgical flap using microvascular tech-niques, or a local flap. The advent of the reversed radialforearm island flap has greatly increased the safety andreliability of local flaps, but the two main disadvantagesof the donor site restrict its clinical applications.

Many suggestions have been made to minimize thedisadvantages of the reverse-flow radial forearm islandflap in hand surgery. These include transferring the deepfascia alone5 or using skin expansion pre- and postop-eratively.6,7 However, these modifications require sac-rificing the radial artery and its venae comitantes.Several studies proved that the radial artery is thedominant artery in the distal forearm and consequentlyconstitutes the major source of vascularization to thehand. It is reasonable to preserve the radial artery forhand circulation.8,9

Encouraged by the introduction of fasciocutaneousflap10 and venous flaps11 in the early 1980s, Changet al.12 in 1988 attempted to raise a reverse-transferredisland fasciocutaneous flap from the radial forearm that

did not include the radial artery. In their report, it wassuccessful in all 10 cases for hand reconstruction. Theythought that the flap was a mixture of fasciocutaneousand venous, and the cephalic vein in the distal pedicleplayed an important positive role for flap survival. Toelucidate the vascular basis of this new flap, we per-formed an anatomic study in 199013 and designed adistally based radial forearm fascial flap for hand re-construction. We found that the pivot point of thepedicle was located 1.0�1.5 cm proximal from the radialstyloid process. In 1992, Goffin et al.14 also performedan anatomic study on the perforators of the distal radialartery, and an island distally based flap was designed.The authors emphasized that the pedicle should be 2 cmabove the tip of the radial styloid process to include allthe peristyloid perforators. In 1993, Smith and Ross15

reported using a tubed fascial flap based on perforatorsof the radial artery to reconstruct the flexor apparatus inone patient. In 1994, Weinzweig et al.16 reported ontheir anatomic study and clinical experiences of distallybased radial forearm fasciosubcutaneous flaps nour-ished by perforators situated 5�8 cm above the radialstyloid process. The anatomic study by Rambe andPho17 in 1995 showed a similar result.

In 1995, Koshima et al.18 introduced a distally basedadipofascial flap for dorsal hand coverage. The flap issupplied by a lateral intertendinous perforator of theradial artery, located within 10 cm proximal to theradial styloid process. Braun et al.19 also reported on adistally based radial forearm fascia-fat flap supplied bydistal perforators at 5�8 cm above the wrist crease.They used this flap to pad and protect the median nerve,to provide a gliding surface for tendon transfer, and toseparate the fresh-cut surfaces of ulna-radius synostosis.In 1995, Bertelli and Kaleli20 performed an anatomicstudy that focused on the vascularization of the lateralantebrachial cutaneous nerve of the forearm, and in-troduced the concept of the neurocutaneous flap.However, the neurocutaneous flap is a specific kind offasciocutaneous flap that includes cutaneous sensorynerves, and its vascularization is originally formed bysepto-fasciocutaneous perforators and strengthened bya paraneural vascular plexus.21 Therefore, neurofascio-cutaneous flaps or neurovenofasciocutaneous flaps maybe more suitable terms.22 In 1997, El-Khatib and Zei-dan23 introduced an anatomic study and 8 cases usingan island adipofascial flap based on distal perforators ofthe radial artery located between 2�7 cm from the radialstyloid process.

In 1998, Jeng and Wei24 reported their clinical ex-periences of 12 cases using distally based radial forearmflaps for hand reconstruction. The pivot point of theadipofascial pedicle was about 2�4 cm above the radialstyloid process. In 2001, Wilson et al.25 used a fascia-fat

Figure 7. Case 2. A: Distally based radial forearm turnover adipo-

fascial flap applied to cover exposed flexor tendons and median

nerve after scar resection. Flap was then covered by full-thickness

skin graft. B: Donor site skin was repositioned and closed directly.

Both survived uneventfully.

Distally Based Radial Forearm Flap 333

flap to create a tube to treat recurrent de Quervain’stendonitis. The pivot point was 5�8 cm proximal to theradial styloid process. In 2002, Medalie26 introduced thesuccessful experience of turnover adipofascial flap fordorsal hand coverage. In 2003, Parodi et al.27 also used afasciosubcutaneous flap for soft-tissue coverage of theflexor aspect of the wrist.

The vascularization of the forearm integument hasbeen studied extensively in the past two decades. Thesestudies mainly focused on axial perforating vessels, e.g.,septocutaneous perforators, fasciocutaneous perfora-tors, and neurocutaneous perforators.28�34

The blood supply to the distally based radial forearmflap in our design is provided by many small arteriesaround the styloid process, and through many layers ofdirectional disposed vascular plexuses of the integumentin the forearm. In histology, these vascular plexuses aremainly composed of arterioles and thoroughfare capil-laries. The flap takes advantage of the lower-resistancechain-linked longitudinally distributed arterial systemsin different planes of the integument. Therefore, a givenarterial inflow pressure through the feeding vessels tothe systems can be easily translated into high blood flow(Poiseulle’s law: Flow = Pressure/Resistance). This highblood inflow can reach a further distance with chain-linked vascular plexuses, and thus results in flaps with agreater length-to-breadth survival ratio. With a 3-cm-wide neuro-veno-adipofascial pedicle based around thewrist, distally based neuro-veno-fasciocutaneous flapscan be safely raised in the forearm with a length to widthratio of 5:1.

According to McGregor and Morgan,35 all surgicalflaps, whatever their designs and compositions, can beclassified as axial-pattern or random pattern, based ontheir anatomic vasculatures and clinical indications. Theaxial-pattern flap is supplied by a big solitary artery, so itcan survive over a large areawith amuchnarrower pedicle

suchas thevascularbundle, and it canbe transferred freelyby microsurgical techniques. While the random-patternflap is supplied by some dispersed small vascularbranches, its survival is limited by the design, with a widebase and the flap’s length-to-width ratio of less than 2:1.As the flap we described has no sizable artery vessel in thepedicle, it is not anaxial-pattern flap.Link-patternmaybea more suitable term to describe this vascularization.36

Chain-linked vascularization of the integument is a spe-cific type of blood supply in the distal forearm and lowerleg.37,38 Compared with axial and random-pattern flaps,link-pattern vascularized flaps have many unique char-acteristics. They can be considered as intermediate be-tween axial and random (Table 2).

In a normal forearm, the venous outflow may beeither through the superficial veins in the subcutaneousadipose tissue or through deep venae comitantes. Bothof these vessels are provided with valves to direct venousreturn proximally. The superficial and deep venoussystems are connected by perforating and communicat-ing veins through the deep fascia that parallel the arte-rial system.39,40 At the proximal end of distally basedflaps, all vessels, whether arterial or venous, are dis-sected and ligated. Therefore, all venous outflow musttheoretically be through the avalvular oscillating veinsuntil they ultimately reach a perforator or communica-tor found in the distal base of the flap; it then continuesto the deep system before orthograde return is reestab-lished. If designed properly,1 the distally based flaps mayalso have physiologic orthograde venous drainage be-cause 1) the valves in the partner ascending or recurrentvenous branches are directed primarily to their distaloriginal stems, and 2) valveless venous plexuses of theintegument serving as oscillating channels allow venousflow in any direction under pressure.

According to Timmons,41 immediate reverse-flow ofvenous blood through a previously competent valve is

Table 2. Comparative Characteristics of Three Types of Flaps

Axial-pattern flap Link-pattern flap Random-pattern flap

Vascular basis Axial single artery Chain-linked directional vascularplexuses

Random vascular networks

Distributed territory Vast Small-medium, potentially enlargedby pressure equilibrium throughchain-linked plexuses

Small

Flap size Large Medium SmallDonor site Specific Distal extremities UbiquitousFlap axis Yes Yes NonePedicle axis Yes Yes NonePedicle width Narrow, only vascular bundle At least 3�4 cm to incorporate

chain-linked plexusesRestricted by flap length

Flap length/pedicle width ratio At surgeon’s will 3�5:1 1.5�2:1Transposition mode At surgeon’s will, including free Pedicled, for local and regional

defectsPedicled, for local defects

334 Chang et al.

possible when the following three criteria are fulfilledtogether: 1) the valve is denervated (e.g., surgical dis-section or anesthetic infiltration), 2) blood filling occursin the veins proximal and distal to the valve, and 3) apressure gradient exists across the valve from proximalto distal. In contrast to reverse-flow island flaps, venousvalves of large subcutaneous veins in distally based flapsare not denervated by extensive surgical dissection, andno high-pressure arterial input of the flap exists toproduce a pressure gradient higher proximally thandistally. Therefore, there is no reverse-flow of venousblood in large superficial veins in simple distally basedflaps.42 Moreover, if a large superficial vein in the distalpedicle is left in continuity to the distal limb after flapelevation, it allows blood to continue to enter the flap,causing venous congestion, increasing drainage load,and jeopardizing flap viability. In such circumstances,large superficial veins have a negative role in venousdrainage for distally based flaps.43 They should be li-gated at the distal base. However, if the large superficialvein distal to the donor site has already been damaged(e.g., by the initial injury), there is no need to dissect andligate it. The dissection and ligation should be per-formed with great care.

Distally based forearm flaps without sacrificing thedeep main artery have been extensively used for handand wrist reconstruction. However, selecting the ap-propriate flap composition is under debate. Regardingthe recipient site prerequisites and donor site morbidity,the advantages and disadvantages of fasciocutaneous vs.adipofascial flaps must be weighed carefully preopera-tively. Our principles in flap-type selection for hand andwrist reconstruction are presented in Table 3.

As a rule in flap surgery, recipient requirements arealways a priority to donor morbidity, and functionalrestoration is usually more important than cosmeticappearance. This is especially true in hand surgery. Inthe clinic, primary closure of both donor and recipientsites without any skin graft is the ideal result. This canbe achieved only in a small number of cases, provided

that the recipient wound is small and the skin island flapis narrow, usually less than 3 cm or one-fifth of theforearm circumference. However, in the majority ofclinical cases, a skin graft is unavoidable, either in thedonor or in the recipient. According to our experience, adistally based radial forearm island fasciocutaneous flapis more suitable for palmar hand coverage. It can pro-vide natural skin to bear friction and pressure. It alsogives better protective sensation if the lateral antebra-chial cutaneous nerve in the flap is coapted with a re-cipient one. On the other hand, an adipofascial flap ismore suitable for soft-tissue reconstruction of the wristand the dorsum of the hand.44 With turnover trans-portation, it can supply sufficient adipose tissue to padand protect the exposed vital structures such as nerves,tendons, and vessels. It also provides subcutaneous fatto allow the tendons to glide through. The superficialradial nerve can be elevated from the subcutaneous fatand left in donor site, even in large adipofascial flaps. Inrecent years, we used turnover adipofascial flaps morecommonly than fasciocutaneous flaps in hand and wristreconstructions. The donor site is closed primarily,whereas the recipient site is skin grafted on the deepsurface of the adipofasical flap.

Since the 1980s, reverse-flow and distally based in-tegument flaps, including fasciocutaneous,3 adipofas-cial,4 and neurocutaneous,20 have been commonly usedfor wound coverage and soft-tissue reconstruction of theextremities. These are good flaps for the hand and wristin the upper limb, and the foot and ankle in the lowerlimb.45,46 However, distally based flaps are not synon-ymous with reverse-flow flaps, although both of themhave the same advantages, including 1) the ability to betransferred from a proximal donor site to a distal re-cipient, 2) avoidance of hand or foot dependence, and 3)the one-stage rapid procedure, which requires nomicrosurgical technique.47 Reverse-flow flaps are sup-plied by nonphysiologic retrograde arterial inflow andvenous outflow through the deep vascular bundles, e.g.,the radial artery and venae comitantes. Distally basedflaps are supplied by a more physiologic circulationthrough collateral vessels, such as the ascending branchof a dominant perforator, the recurrent branch of a di-rect cutaneous vessel, or the chain-linked vascularplexuses of the integument.48

The above-described distally based radial forearmneuro-veno-adipofascial pedicled flap is anatomicallysupplied by numerous small vessels in the distal attachedbase and the rich longitudinally distributed chain-linkedvascular plexuses in the pedicle and flap. The flap can besafely elevated as a long flap with limited pedicle widthin clinical practice. From our experience, some technicaltips should be noted for operative success:49 1) The flapshould be designed in a forearm-neutral position. 2) The

Table 3. Donor and Recipient Site Considerations in Flap-TypeSelection

Fasciocutaneous Adipofascial

Donor siteSmall or narrow flap YesLarge or wide flap YesSensation preservation Yes

Recipient sitePressure-bearing YesVital structure exposure Yes (turnover)Tenolysis or tenorrhaphy Yes (turnover)Neurolysis or neurorrhaphy Yes (turnover)Sensation reconstruction Yes

Distally Based Radial Forearm Flap 335

adipofascial pedicle should be designed wide enough (atleast 3 cm) to incorporate sufficient longitudinal plex-uses of the radial forearm integument. 3) The flapshould be elevated fascio-adipo-cutaneous en bloc; somestitches should be made to hold them together. 4) Thereis no need to identify the perforators in the distal base toavoid injury. 5) The venous drainage of the flap, espe-cially the role of the large subcutaneous vein, should beevaluated after tourniquet release. 6) Subcutaneoustunneling is not appropriate for this wider (3�4 cm) andthicker (adipofascial) pedicle. The skin between donorand recipient sites should be incised and opened up.

The flap described here has many advantages. 1) It isa loco-regional flap for hand surgery, with both donorand recipient sites located within the same operativefield. 2) It provides thin, pliable, hairless, and good-quality skin. 3) It is a simple and rapid one-stage pro-cedure requiring no microsurgical technique. 4) The flapis safe, with robust blood supply. 5) No sacrifice of amajor artery is needed. 5) It can be safely raised, pro-vided that the radial forearm integument is healthy re-gardless of Allen’s test. 6) It is a pedicled flap to betransferred from a proximal donor location to a distalrecipient site as a distally based flap, which is very usefulfor hand reconstruction. 7) It can be a sensate flap if thecutaneous nerve is neurorrhaphied with the recipientnerve. 8) Freedom of arm movement allows for bettercontrol of postoperative edema, early physiotherapy,and mobilization. 9) It is possible to incorporate anadjacent tendon (brachioradialis or palmaris longus) ora piece of radius to make a composite flap transfer.50

There are still some disadvantages of this flap. 1)There is an unsightly scar over the forearm in caseswhere a wide skin island is included and a skin graft isused for its closure. This problem could be solved byraising only an adipofascial flap, leaving the skin graft inthe already injured recipient site. Hui et al.51 reportedthat the small size of donor site defects after a radialforearm flap harvest could be primarily closed success-fully with z-plasties based on the longitudinal skin in-cision. This provides an alternative method for donorsite closure. 2) The adipofascial pedicle is relativelybulky after rotation, which makes direct closure dan-gerous to the pedicle. This can be solved by skin islandextension to the pedicle with a 2-cm skin bridge. 3) Theflap’s survival length-to-width is still limited (greatest at5:1 in our series). It is difficult to reach the distal hand,which restricts its usage in the clinic.

In conclusion, the distally based forearm fasciocu-taneous or adipofascial flap with a wide neuro-veno-adipofascial pedicle pivoted just above the radial styloidprocess is a constant and reliable blood supply. Eleva-tion of the flap is simple and rapid. It has the potentialto provide sensation, and can be performed in a single

stage without microsurgical technique. The flap not onlypreserves the radial artery, but also provides a moreacceptable donor site.

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