The distally-based dorsal hand flap

Transcription

1 British Journal of Plastic Surgery (1990), 43, /90/ /$ The Trustees of British Association of Plastic Surgeons The distally-based dorsal hand flap A. A. QUABA and P. M. DAVISON Lothian Plastic and Oral Surgery Service, Bangour General Hospital, Broxburn, and the Royal Hospital for Sick Children, Edinburgh Summary--The planning and clinical applications of a series of reverse dorsal hand flaps are described. This new flap is based on a direct cutaneous branch of the dorsal metacarpal artery. It is particularly useful in resurfacing web spaces as well as dorsal metacarpal and phalangeal skin defects. The behaviour of 21 such flaps, all raised in the form of an island, was that of a conventional axial pattern flap. Despite detailed description of the vasculature of the hand (Edwards, 1960; Coleman and Anson, 1961 ; Cormack and Lamberty, 1986) a clear account of the source and pattern of the blood supply of the skin covering the dorsum of the hand proper was not available in the English literature until after the publication of the English edition of Michel Salmon's Arteries of the Skin (Salmon, 1988). The recent anatomical studies of Earley (1986) and Earley and Milner (1987) detailed the arterial supply of the first and second web spaces, and its surgical applications. Most flaps raised from the dorsum of the hand have been random pattern, their application being limited by the traditional designs of rotation, advancement and transposition (Lister, 1981). In fact, the plastic surgical literature usually discusses the dorsum of the hand as a recipient rather than as a donor of skin flaps. This paper describes the vascular basis and applications of a series of new flaps derived from the dorsal hand skin. Anatomical considerations It is well recognised that the arterial pattern of the dorsum of the hand is both complex and variable. The dorsal carpal arch is usually formed by the carpal branches of the radial and ulnar arteries with contributions from both the dorsal and palmar interosseous arteries (Coleman and Anson, 1961) (Fig. 1A). In contrast to the first dorsal metacarpal artery, which is a direct branch of the radial artery, the remaining dorsal metacarpal arteries (DMAs) arise from the dorsal carpal arch and, as they run forward, are supplemented or occasionally replaced by perforators from the deep palmar arch or palmar metacarpal arteries which pass through the inter- 28 osseous spaces proximal to the metacarpal heads (Fig. 1B). In general, it can be said that the DMAs diminish in calibre and in incidence as one passes from the radial to the ulnar side of the hand. Additional perforators link the palmar and dorsal systems in the web spaces. The dorsal carpal and First Radi 1. Dorsal carpal arch 2. Deep palmar arch 3. Superficial palmar arch / B Fig. 1 ilrrll carpal arch carpal branch of Ulnar artery Figure 1--(A) Diagram of the dorsal arterial anatomy of the hand. (B) Diagrammatic representation (sagittal view) of the arterial anatomy of the hand; the dorsal metacarpal arteries are joined, and on occasion replaced, by perforators from the deep palmar arch and/or palmar metacarpal arteries.

2 THE DISTALLY-BASED DORSAL HAND FLAP 29 metacarpal vessels lie upon the bones and the interosseous ligaments and muscles. The tendons of the extensor digitorum communis cover the proximal two-thirds of the second to the fourth DMAs. "The dorsal metacarpal arteries each supply two or three serpiginous branches which travel between the tendons and tendon sheaths of the back of the hand to reach the skin where they divide into two or more short branches" (Salmon, 1988). Operative observations The vascular connections between the dorsal hand skin and underlying structures were observed during a large number of surgical procedures which included excision of skin lesions (Fig. 2), extensor tendon repairs and metacarpophalangeal arthroplasties. Significant cutaneous branches of the DMAs were found only in the distal third of the hand and the web spaces. These branches travelled proximally (recurred) forming longitudinally orientated plexuses. It was hypothesised that this arrangement might explain the survival of the narrow strips of skin demarcated by the multiple parallel incisions (corresponding to the underlying tendons of the extensor digitorum communis) used during rheumatoid metacarpophalangeal arthroplasty. It was these operative observations which suggested the feasibility of a long and narrow flap with a pedicle based in the distal third of the hand. They were sufficiently convincing to encourage us to raise the first five flaps reported in this paper prior to carrying out formal cadaver dissections. Cadaver dissections These were carried out on 18 fresh cadaver hands using magnification. As the skin was lifted from Fig. 2 Figure 2--(A) Squamous cell carcinoma of the hand. (B) Vascular connections observed in the distal third during excision.

3 30 BRITISH JOURNAL OF PLASTIC SURGERY proximal to distal (Fig. 3A) the operative observation of the paucity of vascular connections in the proximal two-thirds of the hand was confirmed. In the distal third, a leash of blood vessels was consistently seen leaving each of the second to fourth intermetacarpal spaces distal to the intertendinous connections to enter the overlying skin cm proximal to the corresponding metacarpophalangeal joint (Fig. 3B). A similar but less conspicuous arrangement was seen on the radial and ulnar borders of the hand at about the same level. In each of these vascular leashes a small ( mm) branch which arose directly from the dorsal metacarpal artery (Fig. 3C) or, when the latter is absent, a perforator from the volar system was demonstrated. A network of fine, longitudinally arranged vessels with many anastomoses fanned out proximally in a plane deep to that of the dorsal venous system. Flap design and operative technique A flap may be raised on the second, third or fourth intermetacarpal spaces. It is usually fashioned as an ellipse which may extend from the metacarpophalangeal level to the wrist crease. Its width may vary from 1 to 3.5 cm. The axis of rotation of the flap corresponds to the site where the recurrent cutaneous branch of the dorsal metacarpal vessel enters the skin. This is cm proximal to the adjacent metacarpophalangeal joint (Fig. 4). The flap is raised under tourniquet. Complete exsanguination is avoided to aid visualisation of the pedicle. The skin is incised on one side of the ellipse down to paratenon (Fig. 5A). It is then undermined with care, starting proximally. Tiny vessels emerging from between the extensor tendons may be encountered during undermining (Fig. 5B) and can be sacrificed with impunity. The pedicle is identified distal to the intertendinous connexion of the corresponding intermetacarpal space. Having identified the flap pedicle, i.e. the axis of rotation, and confirmed that the flap is of adequate length, Fig. 3 Figure 3---Cadaver dissections. (A) The dorsal skin is lifted from proximal to distal. (B) A leash of blood vessels (arrowed) can be seen distal to the intertendinous connections. (C) A direct cutaneous branch (arrowed) enters the skin. Fig. 4 Figure ~-Planning : the arterial basis of the flap is a direct branch from the dorsal metacarpal artery. The site of entry of this vessel into the dorsal skin is the axis of the flap. It is situated 0.5 to 1 cm proximal to the adjacent MCPJ. A useful intraoperative guide to this point is the intertendinous connection.

4 THE DISTALLY-BASED DORSAL HAND FLAP 31 Fig. 5 Figure 5---Operative technique: post-electric burn contracture of the middle ring web (the index finger had been amputated). (A) The flap is designed as an ellipse; incision at the radial border down to paratenon. (B) Undermining proximal to the intertendinous connections; serpiginous vessels emerging from between the tendons may be sacrificed. (C) The flap is converted to an island after identifying the pedicle (arrowed). (D) Result 3 months later. the incision is continued onto the other side, ligating the superficial veins as necessary to convert the flap to an island (Fig. 5C). No attempt should be made to skeletonise the pedicle as the connective tissue surrounding the artery may contain a number of veins that can be easily damaged. The arc of rotation (0-180 ) covers the dorsal metacarpal, web and dorsal phalangeal areas including the distal interphalangeal joint (Fig. 6). Long flaps can reach the volar aspect of the web or, if tunnelled through soft tissue, the distal palm. The secondary defect can be closed either directly or by skin grafting. Results This flap has been used in 21 cases (16 elective and 5 emergency), detailed in Table 1, to reconstruct a web space (11) and cover dorsal metacarpal (4), dorsal phalangeal (3) and distal palmar (3) defects. Eleven flaps were raised on the third, 8 on the second and 2 on the fourth intermetacarpal space. Healing by first intention followed an uneventful postoperative course in 18 cases. In one of these, primary venous microanastomosis was necessary to relieve venous congestion which followed release of the tourniquet. Partial or complete necrosis occurred in the remaining three flaps, all of which were destined to cover defects of the distal palm. One flap (Case 13) was lost following the inadvertent division of its pedicle. In Case 4, the flap was tunnelled through the soft tissues of the web to close a distal palmar defect which resulted from release of a tight web and excision of skin involved in a second recurrence of Dupuytren's contracture. This flap looked well perfused upon release of the

5 32 BRITISH JOURNAL OF PLASTIC SURGERY A C i Fig. 6 Figure 6---Diagrams showing the arc of rotation of a flap based on the second intermetacarpal space. tourniquet but, 3 days later, developed venous congestion which progressed to superficial necrosis. No further surgery was necessary. Tip necrosis was observed in a long flap (Case 12) which extended beyond the wrist crease and was raised on badly scarred skin. In 7 cases the donor skin was heavily scarred. The scarring followed the use of split thickness grafts to heal full thickness dorsal hand bums. The transfer in all these cases was uneventful. The configuration of all the flaps was that of an island. No pincushioning was observed following a mean follow-up of 8 months. None of the flaps required thinning or revision even when the flap was used for web reconstruction (Fig. 5). Skin grafting was required to close the secondary defect in Case 1 (acute electric bum) and in the 7 cases of severe post-bum scarring mentioned above. In the remaining cases, closure was by direct approximation. Hypertrophic scarring was noted in three of the younger patients. Discussion This is an axial pattern flap derived from the skin of the dorsum of the hand proper in contrast to

6 THE DISTALLY-BASED DORSAL HAND FLAP 33 Table 1 Details of the clinical cases Case Age Defect Flap dimensions (cm) Closureof secondary defect Space Destination Outcome 1. JB GA AS DC BA 9 6. PW CC KM 9 9. RO MM RC ML CR SC NC MM DH NS NS 20. AS FV Post-excisional 2.5 x 7.5 (acute electric burn) Post-excisional 2.0 x 4.5 (skin growth) Release of recurrent post- 2.0 x 5.5 traumatic contracture Dermatofasciectomy for second recurrence of Dupuytren's contracture Release of post-burn 1.0 x 1.5 contracture of web Acute post-traumatic skin loss 1.5 x 5 exposing extensor tendon Friction burn 2 x 8 Release of syndactyly (Poland's 1 x 2 syndrome) Thermal crush 8.5 x 3 Split skin graft Release of severe post-burn 6.5 x 3 Full thickness claw hand graft Release of post-burn thumb 7.5 x 3.5 adduction contracture Recurrent post-burn flexion 9 x 3 Post-burn metacarpophalangeal joint flexion contracture and webbing Failed thumb replant Release of post-electric burn contracture of web Post-excisional (skin growth) 4 x 2 Release of post-burn claw hand 6 x 3 Fourth Third Third Third Ring, middle and index Successful metacarpophalangeal joints Little metacarpophalangeal joint Ring-little web space Distal palm Successful Successful Partial loss Second Index-middle web Successful Second Dorsum of proximal Successful phalanx of index Third Dorsum of proximal Successful phalanx and proximal interphalangeal joint of ring Second Web of index-middle Successful Third Dorsum of proximal Successful phalanx of ring Second Middle, ring and little metacarpophalangeal joints Successful Full thickness Second First web space Successful graft Full thickness Third Distal palm overlying Successful graft little and ring metacarpophalangeal joints 6.5 x 2 Fourth Little-ring web and Failed distal palm 4x2 6x2.5 Post-burn adduction 3 x 7 and contractures (bilateral, first web) Metacarpophalangealjoint 8 x 3 extension contractures--postburn Tight web space (post- 8 x 3 syndactyly release) Full thickness graft Split skin graft Split skin graft Second First web space Successful Third Ring-middle web Successful Third Ring-middle web Successful Third Ring-little Successful metacarpophalangeal joint Second First web Successful Third Third web space Successful Third Web and volar aspect Successful of proximal phalanges

7 34 BRITISH JOURNAL OF PLASTIC SURGERY Fig. 7

8 THE DISTALLY-BASED DORSAL HAND FLAP 35 Fig. 7 Figure 7--Reconstruction of proximal phalangeal defect. (A) Thermal crush of the index finger. (B) Defect after failure of split skin graft; flap outlined. (C) Close-up view of the defect after debridement showing loss of a segment of the extensor mechanism. (D) The flap with a "vascularised" tendon graft has been raised and (E) transposed using the graft to bridge the extensor gap. (F, G) Closure of the tendon graft donor site. (H, I) Early and late postoperative results. flaps utilising proximal phalangeal or web skin (Iselin, 1973; Foucher and Braun, 1979; Earley and Milner, 1987). It is reliable and easy to raise. The island design and the option of siting the flap on any one of the intermetacarpal spaces increase its territory of cover. It has the usual advantage of a local flap (colour match, skin thickness and texture) which make it particularly suitable to cover metacarpophalangeal and proximal phalangeal as well as web defects. However it should be remembered that the dorsal hand skin may be hair-bearing when considering this flap for web or distal palm reconstruction in males. Flaps as large as 27 cm 2 have been successfully transposed to cover defects which would otherwise have required regional (reverse forearm) or distant flaps. It is worthwhile considering that more than one flap could be raised at the same time, permitting cover of multiple defects. A larger flap could be raised in elective cases if the technique of tissue expansion were to be used; implants would need to be inserted in a pocket in the proximal two-thirds of the hand to avoid damaging potential flap pedicles. While the transposition of this flap on the dorsum of the hand and fingers is straightforward, its movement to cover areas of skin loss localised to the distal palm or the volar aspect of the proximal phalanx is not easy. The bridge of skin between the point of rotation and the free border of the web decreases the effective length of the flap and makes its insetting difficult. Tunnelling the flap through the soft tissues of the web could compromise venous return. More experience is needed before the role of the dorsal hand flap in distal palmar reconstructions could be fully assessed. Donor site morbidity is acceptable. There is minimal interference with postoperative mobilisation irrespective of the method of closure of the secondary defect. It is well-known that scars or grafts on the back of the hand settle down well. With extra care, significant branches of the dorsal ulnar and the superficial radial nerves can be spared during elevation. There has been no problem with distal sensory deficit or symptomatic postoperative neuromas. So far, all flaps have been raised on the second, third and fourth metacarpal spaces. Long and narrow flaps can be raised because of the pattern of the vascular plexus on the dorsum of the hand. The cutaneous blood vessels are arranged in an orderly fashion, along a longitudinal axis which corresponds to the same intermetacarpal space. The anastomoses are numerous. This is in contrast to the arterial circulation of the skin of the palm where the number of vessels is more numerous but the arrangement is haphazard with minimal anastomoses. Being a reverse flap, it is not sensate. It is usually destined to cover areas where crude sensation is sufficient. A longitudinal segment of one of the tendons of the extensor digitorum communis may be incorporated in the flap (Fig. 7). This "vascularised graft" may be used to reconstruct missing distal segments such as the central slip of the

9 36 BRITISH JOURNAL OF PLASTIC SURGERY extensor tendon, making this flap potentially useful to reconstruct cases of boutonni6re deformity with associated skin damage as may occur in burns or rheumatoid arthritis. The flap described in this paper is arterial and not venous. In converting it to an island, the superficial veins are ligated. Also, the flap has been raised successfully in a number of patients who lost the superficial veins following deep granulating burns that required skin grafting (Fig. 8). All the flaps blushed from distal to proximal upon release of the tourniquet. Normal capillary bleeding was observed. It may be argued that this, by itself, may not establish the arterial nature of the flap following the report by Chavoin et al. (1987) on venous flaps which were "immediately normally vascularised, with normal colour and capillary return and with no sign of ischaemia or venous stasis" although this view is not shared by Foucher and Norris (1988). A number of reverse pedicle flaps appeared in the plastic surgical literature following the description of the distally based radial artery forearm flap (Biemer and Stock, 1983). These are of two types. The first is the radial artery flap type whereby an island of skin is carried on an axis of an artery and its venae comitantes. The superficial veins are interrupted and the proximal ends of the vessels forming the pedicle are ligated. Blood flows into and out of the flap via a number of branches and tributaries, contained in a mesentery or a fascial septum. To reach the general circulation, the blood must reverse its flow through the veins (Fig. 9A). This is a true reverse flap. Examples include, in addition to the radial artery flap, the ulnar artery (Lovie et al., 1984) and the anterior tibial artery flap (Wee, 1986). The second type is a flap based on a dominant perforator or a direct cutaneous vessel which enters the flap, anatomically speaking, at its distal end. Although out-flow through superficial veins may be interrupted, venous return via the deep system remains undisturbed (Fig. 9B). Examples include this flap and those of Amarante et al. (1986) and Maruyama and Takeuchi (1986). Obviously, elevation of the latter type of reverse flap is easier and the flow of blood is more physiological. The "ad hoc perforator" flap We believe that in the foreseeable future local flap surgery of the extremities and the trunk will involve exploration, after mapping with a Doppler, for a potential perforator or a cutaneous branch of a known vascular axis adjacent to the defect to be covered to identify a pedicle and establish an axis of rotation for a local island flap which may have a distal or a proximal base. Such a flap may be called the "ad hoc perforator" flap. Acknowledgements All diagrams were drawn by Miss Lesley Skeates, Department of Medical Illustration, Royal Hospital for Sick Children, Edinburgh. The authors would like to thank the staff of the Departments of Medical Photography at Bangour General Hospital, West Lothian, and the Royal Hospital for Sick Children, Edinburgh. The first two flaps were raised at St Andrew's Hospital, Billericay, Essex, in June and August References Amarante, J., Costa, H., Reis, J. and Soares, R. (1986), A new distally based fasciocutaneous flap of the leg. British Journal of Plastic Surgery, 39, 338. Biemer, E. and Stock, W. (1983). Total thumb reconstruction: a one-stage reconstruction using an osteo-cutaneous forearm flap. British Journal of Plastic Surgery, 36, 52. Chavoin, J. P., Rough, D., Vauchaud, M., Boccalon, H. and Costagliola, M. (1987). Island flaps with an exclusively venous pedicle. A report of eleven cases and a preliminary haemodynamic study. British Journal of Plastic Surgery, 40, 149. Coleman, S. S. and Anson, B. J. (1961). Arterial patterns in the hand based upon a study of 650 specimens. Surgery, Gynecology and Obstetrics, 113, 409. Cormaek, G. C. and Lamberty, B. G. H. (1986). The Arterial Anatomy of Skin Flaps. Edinburgh, London, Melbourne, New York: Churchill Livingstone. Earley, M. J. (1986). The arterial supply of the thumb. First web and index finger and its surgical application. Journal of Hand Surgery, IIB, 163. Earley, M. J. and Milner, R. H. (1987). Dorsal metacarpal flaps. British Journal of Plastic Surgery, 40, 333. Edwards, E. (1960). Organization of the small arteries of the hand and digits. American Journal of Surgery, 99, 837. Fuueher, G. and Braun, J. B. (1979). A new islanded flap transfer from the dorsum of the index to the thumb. Plastic and Reconstructive Surgery, 63, 344. Foucher, G. and Norris, R. W. (1988). The venous dorsal digital island flap or the "neutral" flap. British Journal of Plastic Surgery, 41,337. Iselin, F. (1973). The flag flap. Plastic and Reconstructive Surgery, 52, 374. Lister, G. (1981). The theory of the transposition flap and its practical application in the hand. Clinics in Plastic Surgery, 8, 115. Lovie, M. J., Duncan, G. M. and Glasson, D. W. (1984). The ulnar artery forearm free flap. British JournalofPlastic Surgery, 37, 486. Mamyama, Y. and Takeuchi, S. (1986). The radial recurrent fasciocutaneous flap: reverse upper arm flap. British Journal of Plastic Surgery, 39, 458. Salmon, M. (1988). Arteries of the Skin. Taylor, G. I. and Tempest, M. (Eds). London: Churchill Livingstone.

10 THE DISTALLY-BASED DORSAL HAND FLAP 37 B Fig. 8 Figure 8----A flap can be raised on extensively scarred dorsal skin. (A) Severe flame burns. The patient had escharotomies. Granulating wound in the metacarpophalangeal area followed loss of grafts near the necrotic fingers. (B) Recurrent claw-hand deformity. (C) Skin release and flap design. (D) MCPJ capsulectomies and partial release of collateral ligaments. (E) Flap transposed, before and after release of tourniquet; the secondary defect was skin-grafted. (F) Appearance 3 weeks postoperatively. After removal of the K-wires the patient recovered a useful range of movements at the MCPJs.

11 38 BRITISH JOURNAL OF PLASTIC SURGERY A Distal Proximal Distal I ~ Proximal Fig. 9 Figure 9---Reverse or distally-based flaps. (A) Radial artery forearm flap type: the whole vascular axis is incorporated within the flap. Its proximal ends are ligated. Flow within the vessels of the axis is reversed. For simplification, only part of one vein is shown shadowing the artery. (B) In the second type, the direction of flow in the vascular axis remains normal. The flap is supplied via a perforator or a direct cutaneous branch which enters the flap, anatomically speaking, at its distal end.

12 THE DISTALLY-BASED DORSAL HAND FLAP 39 Wee, J. T. K. (1986). Reconstruction of the lower leg and foot with the reverse-pedicled anterior tibial flap: preliminary report of a new fasciocutaneous flap. British Journal of Plastic Surgery, 39, 327. The Authors Awf Quaba, FRCSEd(Plast), Consultant Plastic Surgeon Paul Davison, FRCS, Senior Registrar in Plastic Surgery Lothian Plastic and Oral Surgery Service, Bangour General Hospital, Broxburn, West Lothian, and the Royal Hospital for Sick Children, Edinburgh. Requests for reprints to: Mr A. A. Quaba, FRCSEd(Plast), Royal Hospital for Sick Children, 9 Sciennes Road, Edinburgh EH9 1LF. Paper received 26 June Accepted 7 September The substance of this paper was presented at the British Society for Surgery of the Hand combined meeting with the American Society for Surgery of the Hand, Killarney, May 1988 and at the British Association of Plastic Surgeons Winter Meeting, London, December 1988.