FASHIONING REVERSED AXIAL PATTERN FOREARM TISSUES IN DIFFERENT CHALLENGING CONDITIONS OF THE FOREARM TERRITORY AS A RELIABLE SUBSTITUTE FOR FREE TISSUE TRANSFER

INTRODUCTION

The problem of reconstruction after various types of soft tissue defects of the upper extremity is not new. Nevertheless, the importance of this vast domain is still acute. Extensive trauma, chronic infections and ulcerations, electrical injuries, burns, and tumors are the main etiological factors leading to complex and extensive defects, or to functional losses.

The forearm is a convenient donor site for local flap cover in upper limb defects. Island flaps, based on either of the major forearm arteries, share properties suiting them for reconstruction from elbow to fingertips. The ulnar artery flap has some advantages over the radial flap, especially easy management, low morbidity and better aesthetics of the donor site (1). In addition, free flaps can ensure good and stable coverage, providing healthy tissue for further reconstructive procedures such as tendon transfer or nerve and bone grafting. Functional repair can be achieved in one stage by free flaps, as in flexion or extension restoration of the elbow or digits. Moreover, free flaps can be used as flow-through flaps to restore vascular continuity.

It must be emphasized that the surgeon approaches the issue by considering each patient’s particular needs. Both regional and free flaps have inherent advantages and disadvantages; however, there are many factors which should be considered prior to applying the appropriate technique for each case. This work raised a technical issue; could designed reversed axial island flaps from the forearm area be applicable to any form of soft tissue defects in the territory of the forearm, and could they be considered reliable substitutes for free tissue transfer?

PATIENTS AND METHODS

Thirteen patients who sought surgical treatment for soft tissue defects of the hand, wrist, and distal forearm regions at Assiut University and Assiut Health Insurance hospitals between September 2008 and December 2011 were included in the study. The patients complained of four different etiologies, and their defects were managed by reversed radial forearm flap in eight cases, and by the ulnar variety of the reversed flow forearm flap in another five cases.

Selection of the flap option, either radial or ulnar artery based, depended on the site of the pathology, size and thickness of the resultant defect, special needs of the defect, vascular limitations, and the like-tissue reconstruction objective.

Arterial inflow of the superficial and deep palmar arches was preoperatively established in all cases with Allen’s test. An abnormal test with absent palmar blood flow with radial artery occlusion was considered an absolute contra-indication of these flaps, but this was not established in any of our cases.

The traditional reversed radial forearm flaps were designed as needed and elevated incorporating the radial artery from the forearm, which perfused by retrograde flow through the palmar arch (Fig. 1). More distal defects required more proximal skin paddles. The radial artery and venae commitans were ligated and divided proximally, and the flap was then raised proximal to distal. As the dissection proceeded distally, the pedicle traveled under the brachioradialis muscle. The cephalic vein or a cutaneous vein should be harvested with the flap. The reversed ulnar forearm flaps were designed as needed and elevated based on the ulnar artery, which proximally ligated with its vena commitans after their identification (Fig. 2). The dissection was directed through the deep investing muscle fascia with inclusion of the basilica vein for optimum venous drainage.

Post-burn flexion contracture deformities in the hand and wrist regions were encountered in five patients. All contracting scars and fibrous tissues were excised, and full range of extension movement was obtained intraoperatively. The reversed radial forearm flap was applied for three out of those five patients who had their contracture problems in the radial side of the hand and fingers (Fig. 3), while the reversed ulnar forearm flap was applied for two patients who had their defects after contracture release in the ulnar side of the wrist region.

Post-traumatic soft tissue defects with exposed metacarpal bones and extensor tendons were covered using the reversed radial forearm flap in two cases with extensive defects (Fig. 4), and by using the ulnar variety in another two cases with less extensive wounds.

One radial and one ulnar reversed flow forearm flaps were used to cover the resultant defects (Fig. 5), after excision of chronic unhealed ulcers in the radial side of the wrist and the ulnar side of the distal forearm regions, for 14 and 8 months respectively. Both patients had a past history of failed reconstruction by skin grafting. They had no underlying bone pathology and had negative investigations of abnormal wound healing.

A case with biopsied squamous cell carcinoma in the distal forearm (Fig. 6) and a case with a Marjolin ulcer on the extensor aspect of the wrist joint were managed by reversed radial forearm flaps after complete excisions with safety margins.

The elevated flaps were applied for the concerned defects and fixed by simple sutures. The donor sites were reconstructed by split thickness skin grafts in all cases, except one case of ulnar flap which accepted simple closure. Systemic antibiotics and dressings were applied in all the cases, as soon as appropriate. Patients were allowed to use the donor hands as tolerated, but emphasized elevation was maintained to minimize edema and promote wound and/or skin graft healing.

RESULTS

The mean age of this cohort of cases was 28.5, ranging from 9 to 52. There were eleven males and two females. The mean follow-up duration was 12 months (range: 5–20 months). All flaps survived well with no complications. Both the donor and the recipient sites healed successfully.

In the traumatic soft tissue defects, the large volume of the reversed radial forearm flap was a very suitable solution for such problems, in terms of defect reconstruction and coverage of the exposed vital structures, in two cases. The other two cases had less extensive wounds, not more than 5 x 5 cm², and the smaller ulnar flaps were applicable.

The skin defects following the release of the post-burn contractures were suitably reconstructed by the thin forearm flaps presenting no bulk or interference with the proposed motions postoperatively. Moreover, the flap gliding over the tendons and joints was encouraging for the physiotherapists following these cases, constituting good results.

In post-tumor excision cases, the performed flaps presented the patients with an ideal reconstruction without interference with any further clinical and radiological follow-up of the original malignant condition.

In the patients displaying chronic ulcerations the results were very satisfactory in terms of closing the chronic wounds after the previous failures of skin grafting reconstruction, area re-contouring, and alleviation of the minimal preoperative accompanying lymphoedema. Each of the radial and ulnar flaps used was applied to the same side chronic ulceration, using the required small, thin piece of tissue. The donor site of the ulnar flap in this variety was closed primarily.

Although not reported by the patients, four of them were not satisfied with the colour match of the grafted donor area on inquiry. The difference of colour at grafted areas improved over later follow-up visits. No neuromas or areas of numbness were reported. Three out of these flaps were quite bulky, thus necessitating debulking at later stages. Three patients presented for piecemeal excisions of the grafted donor site areas in later dates.

DISCUSSION

The challenging reconstructive treatment of defects in the upper extremity requires a sound working knowledge of a variety of flaps. The plastic surgeon must weigh the pros and cons of each possible flap to obtain definitive closure and should also integrate the priorities of function, contour, and stability as well as the anticipation of further reconstructive surgery in choosing the flap of choice. Flap selection is based on the characteristics of the defect including size, shape, and location, the availability of donor sites, and the goals of reconstruction (2).

Improved techniques of microsurgery provide the framework for plastic surgeons to offer the most appropriate flap based on donor site, thickness, amount of tissue needed and composition; however, some regional flaps still have the reliable anatomy and the versatile application to be very comparable with what is presented by free flaps. These include reverse radial artery flap, reverse ulnar artery flap and posterior interosseous artery flap.

These regional large flaps which could possibly be harvested from this area were usually the surgeon’s first choice whenever the local resources were stretched. They are characterized by their constant vascular anatomy, ease of elevation, and the long vascular pedicle with a wide arc of rotation. The free flaps present tissue and vascular supply in the same time and have the important advantage of non-sacrifice of a vascular axis of the hand (3). The supreme advantage of the reverse-flow radial and ulnar forearm flaps is the potential offer of thin gliding unit with similar characteristics to the skin over the dorsum of the hand (4).

While comparing our techniques with the free flap interference, there are many issues which should be addressed, including applicability of the axial flaps in many challenging conditions, if they solve the problems, if these solutions are comparable to free flaps, and if their complication rate is comparable to that of free flaps. In this series, the ulnar and radial varieties of the reversed radial forearm flaps were applied for many etiological conditions and presented good comparable results to those reported in the literature for free flaps.

Many complications of the reversed forearm flaps have been reported, including circulatory embarrassment, malfunction of the hand, or acute ischemia of the hand (5). However, none of these complications were found in this series of procedures. One very important step in this regard is checking the continuity of the palmar arch by Allen’s test, which was performed regularly here on every case preoperatively. Moreover, the patency of palmar arch was re-checked intraoperatively by clamping the axial artery just before its division and checking bleeding from the flap edges. On the other hand, free flaps are not free of complications, as reported in many cases involving good hands, which make the reversed axial flaps safer with less records of flap necrosis due to arterial ischemia or venous congestion (6, 7).

In a vascular radiology study, the vascular insufficiency to the hand after raising the radial forearm had been demonstrated by measuring preoperative and postoperative blood flow in the brachial and forearm arteries. Compensatory mechanisms probably mediated by the autonomic nervous system did increase blood flow with statistical significance in the remaining forearm arteries after excision of the radial artery, and total arterial inflow to the hand was not impaired. Similar results could be expected to the ulnar artery sacrifice based on the same mechanism (8). This finding actually omits the main criticism of the reversed flow forearm flaps. Nowadays, many recent anatomical and clinical studies have been applied to modify the dissection of the reversed radial and ulnar forearm flaps as perforator, so as not to sacrifice the major arteries of the forearm (9–11).

Possible functional and aesthetic morbidities at the donor site of the radial and ulnar forearm flaps are well recognized. A skin graft at the donor site can lead to delayed wound healing and tendon exposure, and the resultant scarring is also remarkably unsightly. The free flap donor sites have also similar co-morbidities when compared with the reversed flow flaps. Nowadays, it is also possible to have an oblique design for the skin island of the reverse radial or ulnar forearm flaps, allowing creation of a flap that has a smaller donor defect and yet presents a longer pedicle length, with a wider arc of rotation and better adaptation for direct closure of the donor site (12). Moreover, these flaps could be raised as adipofascial ones to minimize the donor site morbidity and keep the normal skin cover of the forearm (3). In our cases, split-thickness skin grafts were used to cover the donor defects of the forearm. Although the resultant unsightly scar is the major drawback of these techniques, small and medium sized flaps could be closed primarily as reported in one case in the presented cohort. The serial piecemeal excisions of the grafted donor site present more satisfaction to a number of patients in this series.

Keeping in mind all of the characteristics of a flap that are desired for soft tissue coverage, the surgeon must also be aware of other limitations the patient’s body habitus offers. For instance, a free anterolateral thigh flap may be the optimal donor site for wound coverage of the back of the hand in a thin patient, whereas the same flap may not be the first choice in the obese patients because of excessive bulk. A temporal parietal fascial flap leaves a quite inconspicuous scar on the scalp of a young woman, but the same donor site may be unacceptable in a bald man (2). The radial and ulnar forearm flaps have the same characters as the missed tissues in most of the hand and the forearm area, presenting an exact-match tissue which was the most important factor in flap selection in our patients. The selected flaps presented long-lasting close matching of the regional surroundings.

Free tissue transfer might be one of the possible solutions in many of the problems of this series, but more sophisticated demands would be then needed. Extensive preoperative evaluations, presence of adequate recipient vessels, availability of sophisticated equipment and instruments, know-how with microvascular techniques and sufficient time availability all make this procedure less applicable in majority of patients in most situations. The time factor, microsurgical requirements and the fact that some hospitals do not have microsurgical equipment should also be considered limiting factors, while only having good knowledge of harvesting the reversed flow flap types is an encouraging motive to pursue such techniques.

The postoperative time factor is also an important aspect if the patient needs physiotherapy, which is very common in these conditions and should be started early to obtain better results (13). The reversed island flaps can make it possible to start active and passive physiotherapy earlier than with free flaps, and this was applied in our cases (Fig. 7).

The forearm flaps can be raised in varying sizes. Fashioning either quite extensive or small flaps to accommodate large and small defects is very suitable in designing these thin pliable flaps, as seen in this series. As the forearm and hand regions have nearly the same skin and subcutaneous thickness, the reconstructed areas presented good satisfactory results as regard the close texture and color matching with excellent re-contouring.

The thin supple pliable forearm region has a very advantageous tissue supplement, making it applicable to most of the defects resulting from different etiologies in this area. The large volume of the reversed radial forearm flap was a very suitable solution for coverage of the exposed vital structures. In post-burn contractures, the flaps were suitably reconstructed in the released areas by thin gliding non-bulky tissues with the proposed early application of physiotherapy protocols. In post-oncological excision cases, the performed flaps did not interfere with any further clinical and radiological follow-up of the original malignant condition, which is a very important issue while reconstructing such problems. The flaps also presented satisfactory results in closing chronic wounds with regional re-contouring, and alleviation of the accompanying lymphoedema.

CONCLUSION

Harvesting of reversed forearm flaps does not require high surgical skills or special equipment, venous congestion is less significant than with free flaps, and the patients do not need intensive immediate postoperative care and supervision. Preoperative counseling of patients, evaluation of the patency of palmar arch and postoperative physiotherapy of the donor site area remain the precautions to be taken into account while considering these flaps as options which have most of the requirements of ideal soft tissue supply. Reverse forearm flaps are easy and reliable techniques requiring short operating time and allowing initiation of early physiotherapy, when compared with the other techniques such as free flap. Donor site morbidity can be minimized in serial postoperative excisions. The selected flaps in this series were applicable to all etiological applications including covering denuded areas, releasing contractures, re-contouring defects, and reconstructing malignant excisions. They solve the presented problems with comparable results and safer prognosis than free flaps. They could be fashioned to have the advantages of free flaps such as single stage procedures, vascular supply, and size-thickness-texture suitability. Moreover, the disadvantages of donor site morbidity, vascular sacrifice, need for special skills and equipment, and long operative time could be avoided.

Address for correspondence:

Mohamed El-Shazly, M. D.

Department of Plastic Surgery – Assiut University Hospital

71526 Assiut

Egypt

E-mail: elshazly@aun.edu.eg