A distally based first web flap in the foot

Brui.~h ./ournu/ o/ Plmfic Surgrry (1989). 42. 507 5 I I ? 1989 The Trustees of Bntish Assoaation of Plastic Surgeons

0007 I126:89’0041

0507~$10.00

A distally based first web flap in the foot M. J. EARLEY and R. H. MILNER Plastic and Reconstructive

Surgery

Centre,

St Lawrence

Hospital,

Chepstow

Summary-A flap can be raised from the dorsum of the foot based distally on the first web-space. It is supplied by branches of the dorsal and plantar metatarsal arteries and their distal communicating branches. It is reliable, does not contract and is useful in resurfacing defects in the distal foot overlying the metatarsophalangeal joints.

Dorsal foot contractures as a result of traumatic scarring often result in hyperextension of the metatarsophalangeal joints which is difficult to correct permanently. Split thickness skin grafts have a tendency to contract and the use of a flap to fill the defect created following release of the contracture is therefore more desirable. One of the authors (MJE) had been struck by the constancy of vessels supplying the first web-space of the hand and had successfully used a flap islanded on these vessels (Earley. 1986, 1989). Stimulated by this work, a flap based distally on the first web-space of the foot was designed to resurface defects resulting from the release of dorsal foot contractures. Following its clinical use on two occasions, an anatomical study of the vascular supply of the first web-space of the foot was undertaken by one of the authors (RHM) with particular reference to its vascular basis. The blood supply of the flap Twelve adult cadaveric feet were dissected to delineate the arterial anatomy of the first webspace. Eight feet were preserved in 100; form01 saline following the infusion of the whole body with latex according to the method of Tompsett (1970). Four specimens were prepared following latex perfusion of the isolated foot, which were obtained following amputation. The feet were dissected and photographed and the vascular patterns in the foot recorded on standardised charts. In the four latex perfused feet the external diameter of the vessels was measured and recorded under magnification using an operating microscope. The arterial supply of the foot was confirmed as being from the posterior and anterior tibia1 arteries and the peroneal artery. These arteries were connected by three major transverse arches-the

superficial plantar, the deep plantar (usually termed the plantar arch) and the dorsal arch formed by the arcuate artery. Contrary to many standard anatomical textbooks, the lateral plantar artery was not the major contributor to the plantar arch and the deep plantar division of the dorsalis pedis artery was the dominant vessel. In only one foot was the anterior tibia1 artery greatly attenuated, with the dorsalis pedis artery being formed by the anterior branch of the peroneal artery. This pattern has been reported in previous large series (Adachi, 1928; Huber, 1941: Vann, 1943). Both Huber and Adachi showed that the first dorsal metatarsal artery (DMTA) arose from the dorsalis pedis artery in 80% of cases. This was echoed in the present study where it had a dorsal origin in 11 of the 12 feet. Two types of first DMTA were seen, one taking a superficial course (fascial variety) and one being deep within or deep to the first dorsal interosseous muscle itself (muscular variety). Eight feet had fascial first DMTA (Fig. 1) and four were muscular, which agreed with findings by May et al. (1977) and Gilbert (1976). The first plantar metatarsal artery (PMTA) was present in all feet examined and arose in 10 of 12 feet from the deep plantar arch either as a single vessel (7 feet) or as a common vessel with the first DMTA (3 feet). There was a constant anastomotic branching between the first DMTA and first PMTA passing distal to the transverse metatarsal ligament (Fig. 2). These branches have been named the distal (or anterior) communicating arteries (Huber, 1941). In four feet the external diameters of the abovenamed vessels were measured and they are recorded in Table 1. In the distal web-space cutaneous vessels arose from the first DMTA, the DCA and the common digital vessels. Most of these vessels were small

507

508

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DMTA /

Fig. 2

Figure l&Dorsal view of superficial (fascial) variety of first dorsal metatarsal artery. DI = 1st dorsal interosseous muscle, EHB=extensor hallucis brevis, DMTA = 1st dorsal metatarsal artery, DP=dorsalis pedis. Figure t-Cross-sectional view of first web showing superficial (fascial) variety of first DMTA. DCA =distal communicating artery. TML= transverse metacarpal ligament, PMTA = I st plantar metatarsal artery.

Fig. I

although several in each web were of substantial size. In each of the four feet in which the diameter of the vessels entering the subdermal plexus were measured, the number of vessels with a diameter greater than 0.3 mm varied between two and five; several were of the order of 0.7 mm. These first web arterial branches ensured viability of any flap which included them in its subcutaneous pedicle. The patients Six feet were operated upon in five patients. Contractures following burns were released in four feet (three patients) and the flap was used to fill the defects. In three of these, the toes were K-wired in a corrected position for 6 weeks, thereby overcomTable 1 Range

Arterr

0.8-3.1*

Dorsalis pedis Plantar branch dorsalis pedls

(mmi

ing the metatarsophalangeal joint (MTPJ) hyperextension (Figs 3-6). In the fourth, dorsal capsulotomies and extensor tendon lengthening alone were used to release the MTPJ deformity. The mean age of these patients at operation was 8 years, with a range of 6-10 years. The fourth patient suffered a crushing injury of his right foot when only 5 years old, which was allowed to heal by secondary intention resulting in bony loss and scar contracture (Figs 7 and 8). The contracture was released and an iliac cancelious bone graft was used to replace some of the metatarsal gap. This graft was covered by a distally based first web flap which, although suffering some distal superficial skin loss in the first postoperative week, healed uneventfully (Figs 9 and 10). The fifth patient had a hyperkeratotic lesion on the dorsal surface of the hallux which was excised and the defect resurfaced by using a distally based transposition flap from the first web.

of

The method 2. I-2.8

1st DMTA

1.3-1.8

1st PMTA

1.4-2.0

Distal communication artery

0.6-I .9

* Includes one specimen

with a rudimentary

dorsalis

pedis

The flap was raised as a cutaneous one, keeping a generously thick base distally. No effort was made to include the first dorsal interosseous muscle fascia or the first dorsal metatarsal artery itself. Dissection was, therefore. superficial to the tendons of extensor hallucis brevis and longus. The flap was fashioned

A Dl ISTALLY BASED FIRST WEB FLAP IN THE FOOT

Fig. 3

Fig. 5 Figure 3 Typical MPTJ hyperextension deformity due to burn contracture. Figure 4-The and the flap outlined. Figure 5 The flap transposed. Figure bDonor site grafted.

Fig. 4

Fig. 6 defect created

by release. the toes wired

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Fig. 9

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Fig. 8

Fig. IO

Figure ‘I-Shortening and contracture secondary to crushing injury. Figure &X-ray of foot shown in Figure 7. Figure 9-A postoperative view of the foot in Figures 7 and 8. Figure IO--X-ray of foot shown in Figure 9.

Z-year

511

A DISTALLY BASED FIRST WEB FLAP IN THE FOOT

long enough to fill the defect and in four of the six

Acknowledgements

feet had a base-to-length ratio of one-to-three or more (Figs 4 and 5). A split skin or full thickness skin graft was used to close any part of the flap donor site resistant to primary closure (Fig. 6).

The authors wjould like to thank Professor B. T. Pickering and Dr J. H. Musgrave of the Department of Anatomy. llniversity of Bristol. for their help and advlce with the anatomical dissections. and Mr P. J. Sykes for permitting them to include one of his patients. They thank the Department of Medical Illustrations at St Lawrence Hospital and Mrs A. Dymock. Secretary. for their expertise and assistance.

Results With the exception of the delayed healing noted in one patient above, all flaps healed satisfactorily. Three of the four foot contracture releases have had follow-up examinations over a year-and-a-half after surgery (one being 3 years) and none have required secondary operations. There were no donor site problems. Where there was superficial skin loss the flap achieved its objective in releasing the toes and providing vascularised cover for the bone graft, as evidenced by its survival (Fig. 10). Discussion There are few flaps available on the dorsum of the foot and those recognised in the literature are the dorsalis pedis axial flap. neurovascular first web flaps. the toe wrap and hallux transfers, and other toe transfer flaps (Cormack and Lamberty, 1986). In clinical situations such as those described above, the dorsalis pedis flap could not be considered suitable in providing skin cover. In all patients the toes were useful and largely undamaged, therefore excluding their use as filleted flaps. It is unlikely that the neurovascular first web flap would have provided sufficient skin for our patients and, in any event, the dissection would have been more complex (May et al., 1977; Urbaniak, 1988). The distally based first web flap is dependent upon branches of the first dorsal and plantar mei.atarsal arteries and their distal communications, all of which are well described in the literature and confirmed by the dissections cited above. The concept of the flap is similar to those based upon the web-spaces of the hand described by Earley (1986, 1989) and Colville (1987, 1989) and in particular to the distally based dorsal metacarpal flap described by Quaba and Davison (1988). It provides flap cover where a graft is often insufficient and will, therefore, permit the more extensive surgery such as tendon lengthening and dorsal MTJ capsulotomy often required when releasing toe contractures (Yang, 1982). Its use is recommended where distal foot skin cover is required with the only caveat being related to its use in a foot which has suffered a crushing injury or one involving the web-space itself.

References Adachi, B. ( 1918). Dus Arrrriet~.~),srrn? t/w Jupanrr. Volume 2. Kyoto: Universittit zu Kyoto. Colville,J. (1987). Island flap correction ofsyndactyly. Presented at the British Association of Plastic Surgeons. Summer Meeting. Edinburgh. Colville, J. (1989). Syndactyly correction. British Journal of Plasric Surgery. 42. 13. Cormack. G. C. and Lamberty, B. G. H. (1986). i% Arteriml Anatomy c?f Skin Flups. First edition. Edinburgh. London, Melbourne. New York: Churchill Livingstone. Earley, M. J. (19861. The arterial supply of the thumb. first web and mdex finger and its surgical application. .loumcrl of Htrnd SurgurJ,(British Volume), llB, 163. Earley, M. J. (1989). The first web hand flap. Journcrl of Hmd Surgery (British Volume) 14-B. 65. Gilbert, A. (1976). Composite tissue transfers from the foot: anatomic basis and surgical technique. In Daniller. A. J. and Strauch. B. (Eds) .S.mposium qf Microsurgery. St Louis: C. V. Mosby Co., pp. ‘30-241. Huber. J. F. (194 I 1. The arterial network supplying the dorsum of the foot. Anatomical Record, 80, 373. May, J. W., Cbait. L. A., Cohen, B. E. and O’Brien, B. McC. (1977). Free neurovascular flap from the first web of the foot in hand reconstruction. Journalyf Hand Surgery. 2, 387. Quaba, A. A. and Davison, P. (1988). A distally-based dorsal metacarpal hand flap. Presented at the combined meeting of the British and American Societies for Surgery of the Hand, Killarney. May 1988. Tompsett. D. H. (1970). Anammcal Twhniqurs. 2nd Edition. Edinburgh: E. &S. Livingstone. Urbaniak, J. R. (1988). Wrap-around flap: role in thumb reconstruction. In Pho. R. W. H. (Ed.) h~icrosurgipiral Technique in Orrhopaedics. 1st Edition. London. Boston. Durban, Sydney, Singapore, Toronto, Wellington: Butterworths. Vann, H. M. (1941). A note on the formation of the plantar arterial arch of the human foot. Anatomical Record. 85. 269. Yang, Z.-Z. (1982). Plastic surgery in burns. In Yang, C.-C., Hsu. W.-S. and Shih, T.-S. (Eds) Treatment qf Burns. 1st Edition. Berlin, Heidlelberg. New York: Springer-Verlag and Shanghai Scientific and Technical Publishers.

The Authors M. J. Earley, MCb, FRCS(Plast. Surg.), Consultant Plastic Surgeon. St Vincent’s Hospital, Elm Park. Dublin 4, Ireland: formerly Consultant Plastic Surgeon, St Lawrence Hospital, Chepstow. Gwent NP6 5YX. R. H. Milner, RSc, FRCS, Senior Registrar in Plastic Surgery. Royal Victoria Infirmary. Newcastle upon Tyne. Requests

for reprints

to Mr Earley at the Dublin address

Paper received 1 I November 1988. Accepted 14 March 1989 after revision