The Radial Forearm Flap in reconstruction of upper limb injuries: A case series.

Abstract

BACKGROUND: The Radial Forearm Flap is a fasciocutaneous flap which has established its role in soft tissue reconstruction in the head and neck region as a free flap. Its value as a useful flap in soft tissue reconstruction in upper limb injuries has also been recognized. However there has been a dearth of report in our sub region on the use of this flap.

OBJECTIVE: To report the use of Radial Forearm Flap in the reconstruction of traumatic defects in the elbow and hand in our centre.

METHODS: Four cases in which pedicled island Radial Forearm Flaps were successfully used to reconstruct difficult defects in the elbow and hand following injuries were reviewed.

RESULTS: Four pedicled island Radial Forearm Flaps were used to reconstruct soft tissue defects in four sites in the upper limb following trauma. One of the flaps was proximally based for coverage of lateral elbow defect while the others were used to cover defects of dorsum of wrist, mid palmar amputation and first web space. The first web space defect required a fascial flap and split skin graft cover. All the procedures were single staged and the flaps survived providing dependable soft tissue cover.

CONCLUSION: The pedicled radial forearm flap was effective in providing skin cover of difficult soft tissue defects in the elbow, wrist and hand of our patients. It is a single stage procedure which allowed for early mobilization of the limb. Design and elevation of the flap was not as technically demanding as microsurgical tissue transfer which is still in its infancy in most developing countries like Nigeria.

Introduction

The Radial Forearm Flap was first developed in China as a fasciocutaneous flap over thirty years ago1,2.Within the period the flap established itself as a free flap particularly in head and neck reconstruction2,3. Its main virtue as a free flap is as a result of its predictable, large and long pedicle that greatly facilitates micro vascular anastomosis1.Additionally it readily supplies a variety of soft tissue and bone which can be used either singly or in combination, making it a very versatile flap3,4. In Nigeria and a number of developing countries, microsurgical facility is either absent or in its infancy. Partly for this reason, this flap has not yet enjoyed the popularity it has in most developed countries.

However it’s potential as a pedicled flap was also recognized and exploited in a variety of hand reconstructions4,5.We have found the pedicled radial forearm flap either in its fasciocutaneous form or fascial flap useful in the reconstruction around the elbow and the hand. The purpose of this paper is to report our experience with this flap in upper limb reconstruction.

Case Reports

Case 1

A 16 year old boy presented 24 hours after he was attacked by a crocodile. On examination he looked stable but had a large, deep and heavily contaminated wound on the lateral aspect of his right elbow which communicated with the joint. Both radial and ulnar artery pulsations were present distally but radial nerve injury was suspected. Wound exploration further revealed avulsion of the brachioradialis muscle from its origin and crushing in continuity of the radial nerve (Figure 1A).Wound swab was taken which yielded pseudomonas and coliforms. The wound was adequately debrided, irrigated copiously with normal saline and packed with gauze soaked with hydrogen peroxide. The patient was placed on Penicillin, Gentamycin and Metronidazole. Preoperative Allen test was negative. At a second look operation, the wound appeared reasonably clean and a proximally based (Chinese) forearm island flap measuring 6.5cm by 3cm was raised and used to reconstruct the defect. The secondary defect on the volar aspect of distal forearm was resurfaced with split thickness skin graft taken from the contra-lateral thigh. Post operatively the flap survived in its entirety providing primary wound closure and patient could mobilize the elbow joint as from the tenth day post operation (Figure 1B).Total hospital stay was four weeks. When seen two months after discharge from hospital, he had nearly regained normal range of movement at the elbow joint but there was still residual radial nerve palsy.

Fig.1a.

Open right elbow injury following Crocodile bite.

Fig.1b.

Healed elbow injury following proximally-based radial island flap

Case 2

A 32yr old commercial bus driver sustained extensive injury to his non dominant left hand and part of his left forearm when his vehicle skidded and fell on its left side. He reported to the Accident and Emergency unit of the hospital about 24hrs later. Examination revealed extensive crush avulsion injury of the dorsum of left hand with exposed and crushed extensor tendons to the ring, middle and index fingers and open injury of the wrist joint. There was also an area of friction burns involving ulnar border of the proximal third of the forearm. The soft tissue defect was 10cm by 5cm (Figure 2A). Patient had wound debridement same day to remove obviously non- viable tissue. The wound was packed with gauze soaked with hydrogen peroxide. He was placed on oral aumentin^TM and metronidazole. Ten days later he was taken back to theater and further necrotic tissue excised. A distally based radial forearm island flap measuring 9cm by 5 cm was designed and used to cover the defect after a pre-operative negative Allen’s test (Figure 2B).Secondary defect was resurfaced with split thickness skin graft from the thigh. A front slab was used to immobilize the hand and wrist in safe position. Limb elevation was instituted in the immediate post operative period. Post operatively the whole flap survived and patient was discharged to the outpatient after two weeks. He has been undergoing physiotherapy to mobilize his hand and there is plan for extensor tendon reconstruction in future.

Fig.2a.

Extensive post-traumatic soft tissue injury of the dorsum of left hand

Fig.2b.

. Soft tissue cover using distally based radial forearm flap

Case 3

A 23 year old undergraduate, doing part time night job at a plastic manufacturing industry to support him at school, sustained severe industrial machine injury to his dominant right hand. He was brought into our centre about thirty minutes later bleeding profusely. Examination showed that he had traumatic amputation of his right hand at the mid palmar level and through the thumb proximal phalanx (Figures 3A).He was prepared and taken to theatre for wound debridement under tourniquet and the stump was covered with a distally based radial forearm island flap measuring 11.5cm by 7.0cm (Figures 3B).A corrugated rubber drain was inserted. The flap donor site was covered with a split thickness skin graft from the contra-lateral thigh. The drain was removed after 48 hours. The flap survived completely providing primary wound closure. Total hospital stay was about three weeks. When he was seen at the outpatient clinic a year later, the wound cover remained stable.

Fig.3a.

Industrial machinery injury to the right hand

Fig.3b.

Distally based radial forearm flap cover of hand injury

Case 4

A 45 year old auto-mechanic presented three months after sustaining electrical injury to his dominant right hand. He had developed an unsightly scar on the right hand and inability to extend the right thumb. Examination showed a severe flexion and adduction contracture of the right thumb. This was caused by a scar contracture extending from the right thenar eminence to the proximal part of the right thumb. Pre-operative Allen test was negative .The scar was excised and the contracture released completely under tourniquet to get the thumb to full extension and abduction creating a defect over the thenar eminence that extended into the first web space. A distally based radial forearm fascial flap was raised and turned over to cover the defect. The fascial flap was then covered primarily with a split skin graft. The secondary defect on the forearm was closed directly. The post-operative period was uneventful. Patient had 100 % skin graft take and was subsequently discharged to physiotherapy for range of motion exercises. He was followed up for up to one year without recurrence of contracture.

Conclusions

In conclusion, we have found the pedicled radial forearm flap effective in providing skin cover of difficult soft tissue defects in the elbow, wrist and hand of our patients. The flap provided primary wound healing in three acute trauma cases. It is a single stage procedure which allows the limb to be mobilized early in the immediate post operative period and should also reduce hospital stay post operatively. Design and elevation of the flap is not as technically demanding as micro-vascular surgery which is still in its infancy in most developing countries like Nigeria.

Discussion

The radial forearm flap was first developed in China over thirty years ago as a fasciocutaneuos flap1,2. Within the period, the flap established itself as a free flap particularly in head and neck reconstruction2,3. Its main virtue as a free flap is as a result of its predictable, long and wide vascular pedicle that greatly facilitates micro-vascular surgery for free tissue transfer1. Also recognized was the potential of this flap in its pedicled form for reconstruction in the hand4,5.

Soft tissue defects around the elbow, wrist and hand which are not suitable for coverage with split thickness skin cover usually present difficult reconstructive challenges. This is more so if in addition, vital structures like bone, joints, tendons, nerves and blood vessels are exposed. In such situations flap coverage will be required.

Complex injuries around the elbow with loss of overlying soft tissue and exposure of the joint are examples of such difficult defects for which a variety of flaps can be employed for reconstruction. These include local, distant and free flaps. Distant flaps usually from the trunk have been well described 6,7,8. However significant periods of immobilization occasionally in awkward positions in the post-operative period and multi-staged nature of the techniques have been their major drawbacks. Local flaps should be considered since one-stage reconstruction is desirable. The reverse upper arm flap 9,10 and brachioradialis muscle or myocutaneous flaps 11 are examples of local flaps which have been employed in such situations. However in our case 1 above, the brachioradialis muscle was completely destroyed by the crocodile. Like others12 we were also not comfortable with the arc of rotation of reverse upper arm flap for such defects. The proximally based radial forearm island flap provided a dependable soft tissue cover in this patient. The flap was easy to elevate with a long pedicle which allowed such complex defect around the elbow to be reconstructed in a single stage without the need for prolonged immobilization. Previous reports on the use of this flap for elbow coverage have been documented13,14,15. Though they also offer single-stage reconstruction, free flap surgery apart from being quite technically demanding, have not been commonly used in this environment since the technology and expertise are lacking in most developing countries like Nigeria.

Hand injuries which involve substantial skin and soft tissue loss require immediate soft tissue cover to achieve early wound closure and to minimize wound infection, fibrosis and scarring5. The soft tissue cover should not only address the immediate need for wound closure but also the possibility of further surgeries like tendon repairs arthroplasties, bone surgeries etc5. Skin grafts cover will be inappropriate in such situations. Crush and avulsion injuries of the dorsum of wrist and hand are common examples of such difficult soft tissue defects in our environment. In the past, distant flaps from the trunk especially the groin flap16 had dominated the reconstructive options of such defects, but the groin flap suffers from the same disadvantages of distant flaps in hand reconstruction. It is a multi-staged procedure requiring immobilization of the hand in a dependent position for two to three weeks postoperatively to allow for safe flap division and inset5. Edema of hand, interference with hand physiotherapy, stiffness of the ipsi-lateral shoulder joint tends to militate against hand function. Its use in hand reconstruction is therefore on the decline. The distally based island radial forearm flap was our preferred option for the case 2 patient. Apart from the ease of elevation of the flap, it was a single staged procedure providing thin and supple skin for coverage of the dorsum of wrist joint and hand up to the finger knuckles. Hand elevation was possible in the immediate postoperative period and physiotherapy exercises were unhindered. Several authors4,5,12,17 have previously reported on the advantages of distally based island radial forearm flap in hand reconstruction. It can also transfer vascularised bone, tendon and nerve to reconstruct composite defects4.

Our third patient with traumatic amputation at the mid palmar level had the amputation stump covered with a distally based island radial forearm flap. Again it provided primary wound closure in one stage. In this patient consideration was given for the use of split skin graft cover which is simpler. However the amputation defect was irregular with bones sticking out. Split skin graft coverage under such situation will require bone shortening which the patient declined. Also considered was the possibility of future reconstruction to improve hand function and a flap cover will provide a more dependable soft tissue.

The radial forearm flap has also been used as fascial rather than fasciocutaneous flap12,18,19,20.Some of the advantages of the fascial flaps are the reduction in the donor site deformity which can be closed directly, avoidance of hair in palmer reconstruction in hirsute individuals and reduction of the thickness of subcutaneous tissue in some patients particularly females12.In our fourth patient, we required thinner tissue than would have been provided by a fasciocutaneous flap. Split thickness skin graft alone would have led to recurrence of contracture and we reasoned that fascial flap covered with skin graft will provide tissue of adequate thinness with less possibility of contracture recurrence. The direct closure of the donor site in this patient was an added advantage. Use of skin grafted fascial flaps in hand reconstruction has also been previously reported20.

The major concerns when using the radial forearm fasciocutaneuos flap had been the donor site morbidity4. These include the sacrifice of a major source artery to the forearm and hand and the wound healing problems and poor aesthetic appearance of the donor site of the flap which most often requires to be skin grafted. To avoid hand ischaemia when using the radial artery forearm flap, it is important to establish that the rest of the hand will survive on the ulnar artery input alone. A timed Allen test is therefore mandatory5. Allen test requires that the patient makes a tight fist to exsanguinate the hand. This obviously presents a problem in acute hand trauma. In such situations some authors have proposed intra-operative Allen test by clamping the radial artery either proximally or distally5,12. However in two of our patients with acute hand trauma we rather exsanguinated the hand under general anesthesia and proceeded with Allen test. Although ulnar artery flap is another forearm flap described for both elbow, hand and wrist coverage, it has not been popular with us and others12 because the ulnar artery is commonly the dominant blood supply to the hand. Posterior interosseous artery flap based on the posterior and anterior interosseous arteries and dorsal carpal arch has also been used for hand coverage22. Its major advantage is that it does not sacrifice any of the major source vessels to the forearm and hand. However its dissection is quite delicate and the extent of coverage in the wrist and hand is much less than the radial forearm flaps12.

The wound healing problems and appearance of donor site of the radial forearm flap are well documented5,23,24. Complications are more in composite flaps than in ordinary fasciocutaneous flap24. The skin grafted donor site usually produces poor aesthetic results. Various authors have suggested ways to minimize this24,25. We agree with others5 that the handling of the donor site should be quite meticulous and possibly its closure should not be delegated to the inexperienced member of the team. The possibility of scar hypertrophy is usually discussed with the patient since most of our patients are blacks and therefore prone to scar hypertrophy and keloids. However the scar hypertrophy seen in these patients were mainly in the skin grafted donor sites and tended to subside with time.