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The instep island flap to resurface plantar defects
British journal ofPlastic Surgery (1981) 34, 315-318 0 1981 The Trustees of British Association of Plastic Surgeons
0007.12?6.81’02?0-0315
$02.00
The instep island flap to resurface plantar defects DOUGLAS Regional
H. HARRISON
Plastic
and Jaw
and
Surgery
BRIAN
Centre,
D. G. MORGAN
Mount
Vernon
Hospital,
Northwood,
Middlesex
Summary-An instep island neurovascular flap is described based on the medial plantar artery of the foot. It is simple to elevate, transposes easily into calcaneal defects and provides a new nerve supply. The donor site may be skin grafted and since it does not lie on the weightbearing surface of the foot, there have been no difficulties with walking.
The problems of resurfacing the sole of the foot have been described by Maisels (1961) and Curtin (1977) and more recently by Sommerlad and McGrouther (1978) who concluded that no form of distant sole replacement was satisfactory and reported that most patients avoided weightbearing on a resurfaced area. The skin and subcutaneous tissue on the sole of the foot are perfectly adapted to their function and strong, fibrous septa support and maintain the tissues in position. Should it be necessary to resurface the crescentic weightbearing area of the foot the local transposition of the specialized plantar skin would be preferable to cover by a distant flap or a skin graft. Apart from size there are inherent difficulties in the transfer of local tissue on the sole of the foot. Transposition flaps elevated superficial to the plantar fascia require “delay” due to their precarious random pattern blood supply based on perforating vessels from the medial and lateral plantar vessels. “Delay” procedures produce fibrosis at the flap interface so that an already unyielding flap becomes even less mobile. Any transposition flap, whether based medially or laterally, will tend to violate the weightbearing surface, with consequent hypersensitivity of the scar. Sensation is of paramount importance to provide warning of excessive stress. Local transposition flaps recover sensation in the course of time (Curtin, 1977) but rarely is it of normal quality. The neurovascular island flaps described by Snyder and Edgerton (1965) and Kaplan (1969) required sacrifice of toes and careful dissection of the lateral plantar and dorsalis pedis arteries, whichever vessel forms the metatarsal vascular arch. The medial plantar artery only rarely forms the metatarsal arch according to Snyder and Edgerton (1965). Furthermore, the area of skin
provided from the filleted toe was relatively small and its use was limited to smaller lesions. Shanahan and Gingrass (1979) transposed a flap on the instep based on the medial plantar artery and nerve, but delayed it and retained a skin bridge which can make the transposition more difficult and leaves a “dog ear”. In 1977 we had carried out cadaver dissections to fashion an instep flap based on the medial plantar artery and the long saphenous vein in order to carry out a free cross-foot flap (Mir y Mir, 1954) but a suitable occasion did not arise at that time.
Surgical Anatomy The medial plantar artery is the smaller of the two plantar arteries and originates at the bifurcation of the posterior tibia1 artery. It passes beneath the abductor hallucis muscle to enter the sole. It then proceeds distally running below and lateral to the abductor hallucis, lying in thin areolar tissue on the flexor digitorum accessorius (quadratus plantae) muscle. The arterial supply to the skin is provided by a perforating vessel from the medial plantar artery on each side of the abductor hallucis muscle and also by a myocutaneous circulation through the abductor . hallucis (Fig. lA, B). Confirmation of the blood supply to the skin provided by this artery was achieved by injecting methylene blue directly into the medial plantar artery in a patient immediately prior to an above-knee amputation. The dye first became apparent in the skin over the central area of the instep. It then rapidly spread out from this point to include the medial half of the foot (Fig. 2). The medial plantar artery continues distally and may terminate in superficial branches to the first and second toe 315
316
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
with perforating branches through to the dorsalis pedis artery and deep metatarsal arch. The deep venous return from the sole is by venae comitantes running alongside the medial and lateral plantar arteries and also a superficial system which converges on the long saphenous vein. The medial plantar nerve runs alongside the medial plantar artery, lying deep to it in the proximal sole: It supplies the flexor digitorum brevis and abductor hallucis muscle, the skin of the medial 33 toes and by cutaneous branches in the proximal sole provides sensation to the instep area. Elevating the Instep Island Flap
Plant.
‘APon.
Fig. 1 A, B. Cadaver dissection and diagram to show the course of the medtal plantar artery from its origin from the posterior tibia1 artery to the distal sole and its relation to the abductor hallucis and the medial plantar nerve.
A flap 10 cm long x 7 cm wide may be elevated from the instep region without encroaching on the weight-bearing surface. A flap of suitable size and designed to allow easy transposition into the intended defect is cut. The incision is extended to a point just posterior to the medial malleolus. The posterior tibia1 artery is isolated at this point and dissected distally to its bifurcation. The bifurcation lies deep to the origin of the abductor hallucis muscle and this structure is divided. Dissection of the lateral plantar neurovascular bundle is relevant so that a cleft may be formed between the two neurovascular territories to permit easy transposition of the flap. Having found the medial plantar artery and nerve and defined the medial and lateral extent of the pedicle, further dissection proceeds in a distal to proximal fashion. The distal extremity of the flap is taken down to the neurovascular plane on the flexor hallucis brevis, which covers the flexor hallucis longus. The plantar digital nerves are preserved, but the distal end of the medial plantar artery is divided and elevated with the flap. The plane of dissection is immediately superficial to the medial plantar nerve. The cutaneous branches of the medial plantar nerve supplying the flap come off proximally and care must be taken to avoid severing them. If increased mobility of the flap is required perineural dissection of these filaments may be indicated. The dissection is completed by joining the deep dissection with the previously formed medial and lateral boundaries. Case Report
Fig. 2 Within a few seconds of injection of methylene blue into the medial plantar artery, dye can be seen staining the skin in the instep area.
A 15-year-old girl presented with a 5 x 6 cm callosity over the lateral calcaneal region of her left foot (Fig. 3).
THE
INSTEP
ISLAND
FLAP
TO
RESURFACE
PLANTAR
317
DEFECTS
She had a congenital spinal lesion at the Sl and L5 level that made the proximal part of the sole insensitive. The callosity was aggravated by a mid-foot hyperextension which transmitted more than the usual 800, of the body weight directly through the calcaneum (Jones, 1941). The callosity extended down to the bone itself.
Fig. 5 The instep flap is transposed comfortably into the excisional defect. The plane of dissection is demonstrated with the medial plantar nerve preserved deeply.
Fig. 3 Callosity (5 x 6 cm) over the OS calcaneum penetrating deeply and fixed to the bone
The callosity was excised and the resulting defect was resurfaced by an instep island flap measuring 6 x 5 cm (Figs. 4. 5). The donor site was covered with a thick split-skin graft (Fig. 6). The flap survived completely and a good take of the skin graft was achieved. The cutaneous nerves from the medial plantar nerve were preserved in the dissection and improved the quality of sensation over the calcaneum (Fig. 7). The sub-normal sensation in this case did not detract from the success of the flap itself but was rather a specific neurological problem in this particular patient.
Fig. 4 After excision of the callosity, the instep has been defined with incisions for the proximal and communicating incision.
Fig. 6 Instep island flap sutured skin graft sewn mto the secondary
island flap dissection Fig. 7
Early postoperative
result.
into place and a thick split defect.
318
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
Discussion
It is particularly difficult to transpose the skin of the foot because of multi-directional fibrous septa which reduce flexibility. Division of the skin base and reliance on the neurovascular pedicle makes the flap considerably more mobile and much easier to set into a preformed defect. Neurovascular island flaps have been previously designed by filleting toes. Although these flaps may be used for calcaneal defects, the arterial supply is variable and in some cases the metatarsal arch may be formed largely by the dorsalis pedis artery. The commoner vessel of supply is the lateral plantar artery and incisions across the weight-bearing surface of the foot then become mandatory. Loss of a toe or toes is cosmetically unsightly and loss of the big toe may affect the balance in walking. Filleted toes are possibly more useful in distal plantar skin loss and in the closure of small defects in this area. Transposition flaps, which may require a “delay”, require incisions that extend on to weight-bearing surfaces, transpose with difficulty, often leave “dog ears” which take time to flatten out or need secondary correction. Although the instep island flap incorporates the abductor hallucis muscle and to some extent is myocutaneous, it is clear that if the medial plantar artery is incorporated with the flap, the skin area available for transfer far exceeds the dimensions of the abductor hallucis muscle. The instep island flap is usually transferred laterally and it is therefore necessary to divide the branches to the long saphenous vein on the medial side of the flap. The venous drainage is provided by the venae comitantes to the medial plantar artery. Cadaver dissections have shown that it would be a simple matter to raise the flap based on the medial plantar artery and if necessary include the posterior tibia1 artery with venous drainage provided by the long saphenous vein. This extended flap might then provide sufficient tissue to resurface the heel of the opposite foot should the occasion arise.
Curtin, J. W. (1977). Functional surgery for intractable conditions of the sole of the foot. Plastic and Reconstructioe Surgery, 59, 806. Jones, R. L. (1941). The human foot; an experimental study of its mechanics and the role of the muscles and ligaments in the support of the arch. American Journal of Anatomy, 68, 1. Kaplan, I. (1969). Neurovascular island flap in the treatment of trophic ulceration of the heel. British Journal of Plastic Surgery, 22, 143. Lister, G. D. (1978). Use of an innervated skin graft to provide sensation to the reconstructed heel. Plastic and Reconstructive Surgery, 62, 157. Maisels, D. 0. (1961). Repairs of the heel. British Journal of Plastic Surgery. 14, 117. Mir y Mir, L. (1954). Functional graft of the heel. Plastic and Reconstructive Surgery, 14, 444. Shanahan, R. E. and Gingrass, R. P. (1979).
Medial plantar sensory flap for coverage of heel defects. Plastic and Reconstructive Surgery, 64, 295. Snvder. G. B. and Edgerton. M. T. (196%. The urineiDle of the island neurovascular flap in the management of ulcerated anaesthetic weight-bearing areas of the lower extremity. Plastic and Reconstructive Surgery, 36, 518. Sommerlad, B. C. and McGrouther, D. A. (1978). Resurfacing the sole; long-term follow-up and comparison of techniques. British Journal of Plastic Surgery, 31, 107. ”
I
D
,
I
1
.
Acknowledgements We wish to thank Mr Ron Blake of the Photographic Department, Mount Vernon Hospital, for the photographs and Mr I. W. Winchester, Consultant Orthopaedic Surgeon, Whittington Hospital, London, for referring the patient.
The Authors D. H. Harrison, FRCS, Consultant Plastic Surgeon. B. D. G. Morgan, FRCS, Consultant Plastic Surgeon
Requests for reprints to: D. H. Harrison, Regional Plastic and Jaw Surgery Centre, Mount Vernon Hospital, Northwood, Middlesex.
0007.12?6.81’02?0-0315
$02.00
The instep island flap to resurface plantar defects DOUGLAS Regional
H. HARRISON
Plastic
and Jaw
and
Surgery
BRIAN
Centre,
D. G. MORGAN
Mount
Vernon
Hospital,
Northwood,
Middlesex
Summary-An instep island neurovascular flap is described based on the medial plantar artery of the foot. It is simple to elevate, transposes easily into calcaneal defects and provides a new nerve supply. The donor site may be skin grafted and since it does not lie on the weightbearing surface of the foot, there have been no difficulties with walking.
The problems of resurfacing the sole of the foot have been described by Maisels (1961) and Curtin (1977) and more recently by Sommerlad and McGrouther (1978) who concluded that no form of distant sole replacement was satisfactory and reported that most patients avoided weightbearing on a resurfaced area. The skin and subcutaneous tissue on the sole of the foot are perfectly adapted to their function and strong, fibrous septa support and maintain the tissues in position. Should it be necessary to resurface the crescentic weightbearing area of the foot the local transposition of the specialized plantar skin would be preferable to cover by a distant flap or a skin graft. Apart from size there are inherent difficulties in the transfer of local tissue on the sole of the foot. Transposition flaps elevated superficial to the plantar fascia require “delay” due to their precarious random pattern blood supply based on perforating vessels from the medial and lateral plantar vessels. “Delay” procedures produce fibrosis at the flap interface so that an already unyielding flap becomes even less mobile. Any transposition flap, whether based medially or laterally, will tend to violate the weightbearing surface, with consequent hypersensitivity of the scar. Sensation is of paramount importance to provide warning of excessive stress. Local transposition flaps recover sensation in the course of time (Curtin, 1977) but rarely is it of normal quality. The neurovascular island flaps described by Snyder and Edgerton (1965) and Kaplan (1969) required sacrifice of toes and careful dissection of the lateral plantar and dorsalis pedis arteries, whichever vessel forms the metatarsal vascular arch. The medial plantar artery only rarely forms the metatarsal arch according to Snyder and Edgerton (1965). Furthermore, the area of skin
provided from the filleted toe was relatively small and its use was limited to smaller lesions. Shanahan and Gingrass (1979) transposed a flap on the instep based on the medial plantar artery and nerve, but delayed it and retained a skin bridge which can make the transposition more difficult and leaves a “dog ear”. In 1977 we had carried out cadaver dissections to fashion an instep flap based on the medial plantar artery and the long saphenous vein in order to carry out a free cross-foot flap (Mir y Mir, 1954) but a suitable occasion did not arise at that time.
Surgical Anatomy The medial plantar artery is the smaller of the two plantar arteries and originates at the bifurcation of the posterior tibia1 artery. It passes beneath the abductor hallucis muscle to enter the sole. It then proceeds distally running below and lateral to the abductor hallucis, lying in thin areolar tissue on the flexor digitorum accessorius (quadratus plantae) muscle. The arterial supply to the skin is provided by a perforating vessel from the medial plantar artery on each side of the abductor hallucis muscle and also by a myocutaneous circulation through the abductor . hallucis (Fig. lA, B). Confirmation of the blood supply to the skin provided by this artery was achieved by injecting methylene blue directly into the medial plantar artery in a patient immediately prior to an above-knee amputation. The dye first became apparent in the skin over the central area of the instep. It then rapidly spread out from this point to include the medial half of the foot (Fig. 2). The medial plantar artery continues distally and may terminate in superficial branches to the first and second toe 315
316
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
with perforating branches through to the dorsalis pedis artery and deep metatarsal arch. The deep venous return from the sole is by venae comitantes running alongside the medial and lateral plantar arteries and also a superficial system which converges on the long saphenous vein. The medial plantar nerve runs alongside the medial plantar artery, lying deep to it in the proximal sole: It supplies the flexor digitorum brevis and abductor hallucis muscle, the skin of the medial 33 toes and by cutaneous branches in the proximal sole provides sensation to the instep area. Elevating the Instep Island Flap
Plant.
‘APon.
Fig. 1 A, B. Cadaver dissection and diagram to show the course of the medtal plantar artery from its origin from the posterior tibia1 artery to the distal sole and its relation to the abductor hallucis and the medial plantar nerve.
A flap 10 cm long x 7 cm wide may be elevated from the instep region without encroaching on the weight-bearing surface. A flap of suitable size and designed to allow easy transposition into the intended defect is cut. The incision is extended to a point just posterior to the medial malleolus. The posterior tibia1 artery is isolated at this point and dissected distally to its bifurcation. The bifurcation lies deep to the origin of the abductor hallucis muscle and this structure is divided. Dissection of the lateral plantar neurovascular bundle is relevant so that a cleft may be formed between the two neurovascular territories to permit easy transposition of the flap. Having found the medial plantar artery and nerve and defined the medial and lateral extent of the pedicle, further dissection proceeds in a distal to proximal fashion. The distal extremity of the flap is taken down to the neurovascular plane on the flexor hallucis brevis, which covers the flexor hallucis longus. The plantar digital nerves are preserved, but the distal end of the medial plantar artery is divided and elevated with the flap. The plane of dissection is immediately superficial to the medial plantar nerve. The cutaneous branches of the medial plantar nerve supplying the flap come off proximally and care must be taken to avoid severing them. If increased mobility of the flap is required perineural dissection of these filaments may be indicated. The dissection is completed by joining the deep dissection with the previously formed medial and lateral boundaries. Case Report
Fig. 2 Within a few seconds of injection of methylene blue into the medial plantar artery, dye can be seen staining the skin in the instep area.
A 15-year-old girl presented with a 5 x 6 cm callosity over the lateral calcaneal region of her left foot (Fig. 3).
THE
INSTEP
ISLAND
FLAP
TO
RESURFACE
PLANTAR
317
DEFECTS
She had a congenital spinal lesion at the Sl and L5 level that made the proximal part of the sole insensitive. The callosity was aggravated by a mid-foot hyperextension which transmitted more than the usual 800, of the body weight directly through the calcaneum (Jones, 1941). The callosity extended down to the bone itself.
Fig. 5 The instep flap is transposed comfortably into the excisional defect. The plane of dissection is demonstrated with the medial plantar nerve preserved deeply.
Fig. 3 Callosity (5 x 6 cm) over the OS calcaneum penetrating deeply and fixed to the bone
The callosity was excised and the resulting defect was resurfaced by an instep island flap measuring 6 x 5 cm (Figs. 4. 5). The donor site was covered with a thick split-skin graft (Fig. 6). The flap survived completely and a good take of the skin graft was achieved. The cutaneous nerves from the medial plantar nerve were preserved in the dissection and improved the quality of sensation over the calcaneum (Fig. 7). The sub-normal sensation in this case did not detract from the success of the flap itself but was rather a specific neurological problem in this particular patient.
Fig. 4 After excision of the callosity, the instep has been defined with incisions for the proximal and communicating incision.
Fig. 6 Instep island flap sutured skin graft sewn mto the secondary
island flap dissection Fig. 7
Early postoperative
result.
into place and a thick split defect.
318
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
Discussion
It is particularly difficult to transpose the skin of the foot because of multi-directional fibrous septa which reduce flexibility. Division of the skin base and reliance on the neurovascular pedicle makes the flap considerably more mobile and much easier to set into a preformed defect. Neurovascular island flaps have been previously designed by filleting toes. Although these flaps may be used for calcaneal defects, the arterial supply is variable and in some cases the metatarsal arch may be formed largely by the dorsalis pedis artery. The commoner vessel of supply is the lateral plantar artery and incisions across the weight-bearing surface of the foot then become mandatory. Loss of a toe or toes is cosmetically unsightly and loss of the big toe may affect the balance in walking. Filleted toes are possibly more useful in distal plantar skin loss and in the closure of small defects in this area. Transposition flaps, which may require a “delay”, require incisions that extend on to weight-bearing surfaces, transpose with difficulty, often leave “dog ears” which take time to flatten out or need secondary correction. Although the instep island flap incorporates the abductor hallucis muscle and to some extent is myocutaneous, it is clear that if the medial plantar artery is incorporated with the flap, the skin area available for transfer far exceeds the dimensions of the abductor hallucis muscle. The instep island flap is usually transferred laterally and it is therefore necessary to divide the branches to the long saphenous vein on the medial side of the flap. The venous drainage is provided by the venae comitantes to the medial plantar artery. Cadaver dissections have shown that it would be a simple matter to raise the flap based on the medial plantar artery and if necessary include the posterior tibia1 artery with venous drainage provided by the long saphenous vein. This extended flap might then provide sufficient tissue to resurface the heel of the opposite foot should the occasion arise.
Curtin, J. W. (1977). Functional surgery for intractable conditions of the sole of the foot. Plastic and Reconstructioe Surgery, 59, 806. Jones, R. L. (1941). The human foot; an experimental study of its mechanics and the role of the muscles and ligaments in the support of the arch. American Journal of Anatomy, 68, 1. Kaplan, I. (1969). Neurovascular island flap in the treatment of trophic ulceration of the heel. British Journal of Plastic Surgery, 22, 143. Lister, G. D. (1978). Use of an innervated skin graft to provide sensation to the reconstructed heel. Plastic and Reconstructive Surgery, 62, 157. Maisels, D. 0. (1961). Repairs of the heel. British Journal of Plastic Surgery. 14, 117. Mir y Mir, L. (1954). Functional graft of the heel. Plastic and Reconstructive Surgery, 14, 444. Shanahan, R. E. and Gingrass, R. P. (1979).
Medial plantar sensory flap for coverage of heel defects. Plastic and Reconstructive Surgery, 64, 295. Snvder. G. B. and Edgerton. M. T. (196%. The urineiDle of the island neurovascular flap in the management of ulcerated anaesthetic weight-bearing areas of the lower extremity. Plastic and Reconstructive Surgery, 36, 518. Sommerlad, B. C. and McGrouther, D. A. (1978). Resurfacing the sole; long-term follow-up and comparison of techniques. British Journal of Plastic Surgery, 31, 107. ”
I
D
,
I
1
.
Acknowledgements We wish to thank Mr Ron Blake of the Photographic Department, Mount Vernon Hospital, for the photographs and Mr I. W. Winchester, Consultant Orthopaedic Surgeon, Whittington Hospital, London, for referring the patient.
The Authors D. H. Harrison, FRCS, Consultant Plastic Surgeon. B. D. G. Morgan, FRCS, Consultant Plastic Surgeon
Requests for reprints to: D. H. Harrison, Regional Plastic and Jaw Surgery Centre, Mount Vernon Hospital, Northwood, Middlesex.