NEUROVASCULAR ISLAND FLAP IN THE TREATMENT OF TROPHIC ULCERATION OF THE HEEL By ISIDORE KAPLAN, F.R.C.S., F.R.C.S.(Ed.) Johannesburg, South Africa THE transfer of skin and subcutaneous tissue on a neurovascular pedicle is a wellestablished surgical procedure. The island flap allows for the migration of tissue endowed with both vascular and nerve supply. Since Littler (196o) and Tubiana (196o) described the technique and concept of this flap in the field of hand surgery, it has been widely and successfully used. Further extensions and wider applications have developed. Trophic ulceration of the heel presents numerous problems relating to the indolence of healing and marked tendency to recurrence. Often the usual methods of obtaining sound durable skin cover by means of free skin grafts, local skin flaps and distant flaps, do not provide the weight-bearing surface with skin of adequate texture and sensation. Recurrences are frequent and frustrating, yet unavoidable, in view of the fact that in the vast majority of cases the entire foot and heel lack sensation. In certain instances, however, trophic ulceration of the heel may be associated with intact sensation on the plantar surface of the toes. Under these circumstances, the transfer of an island flap from a " silent" or more expendable area of the foot would seem to offer a sound and rational method of approach. Surgical Anatomy.--Basically the anatomical arrangement of the blood and nerve supply of the foot resembles the hand very closely. The following description of the neurovascular supply is taken from Grays Anatomy (1942) : Nerve Supply (Fig. I).--The medial plantar nerve accompanied by and lying lateral to the medial plantar artery, is located under the flexor retinaculum, passing deep to the abductor hallucis muscle. The nerve then appears in the interval between the abductor hallucis muscle and the flexor digitorum brevis muscle. At this level, the digital nerve to the medial side of the big toe is given off, supplying the skin over the plantar surface of the medial half of the big toe. The medial plantar nerve divides into three plantar digital nerves. The three plantar digital nerves pass between the divisions of the plantar aponeurosis splitting in two branches--the first supplying the adjacent sides of the big and second toes, the second the adjacent sides of the second and third toes, while those of the third plantar digital nerve supply the adjacent sides of the third and fourth toes. The lateral plantar nerve supplies the skin of the fifth toe and the lateral half of the fourth toe. It will be seen that the digital branches of the medial plantar nerves are similar to the median nerve in the hand and the lateral plantar nerve to the ulnar nerve distribution in the hand. Vascular Supply (Fig. 2). Medial Plantar Artery.--The medial plantar artery is the smaller terminal branch of the posterior tibial artery and accompanies the medial plantar nerve which lies on its lateral side. At the base of the first metatarsal bone, where it is much diminished in size, it passes along the medial border of the first toe and anastomoses with the first dorsal metatarsal artery. It supplies three small superficial digital branches which accompany the digital branches of the medial plantar nerve and joints the first, second and third plantar metatarsal arteries. 143
144 BRITISH JOURNAL OF PLASTIC SURGERY Lateral Plantar Artery.--The lateral plantar artery which is the larger of the terminal branches of the posterior tibial artery passes obliquely, laterally and forwards to the base of the fifth metatarsal bone in company with the lateral plantar nerve which lies on its medial side. It then turns medially with a deep branch of the nerve to the interval between the base of the first and second metatarsal bones where it unites with the dorsalis pedis artery completing the plantar arch. & BRI FROM " "If,sT PLANTAr- METATARSAL A. t~'~/ 'BRANCH A.DORSALIS PEDIS DIGITAL BRANC H CUTANEOUS BR M PL.a MED. PLANTAR LAT PLAN FAR THE PLANTAR NERVES FIG. I Nerve supply. THE PLANTAR ARTERIES FIG. 2 Vascular supply. This classical description, as Snyder and Edgerton (I965) have pointed out, is often not consistent. These authors found that in their dissected cadavers the great toe was supplied almost exclusively by a metatarsal branch arising from the dorsalis pedis circulation on the dorsum of the foot near the base of the metatarsals. These authors therefore draw attention to this variation and its significance in attempting to isolate the neurovascular bundle in dissection. CASE REPORT.--The patient, a 53-year-old bricklayer, had developed an ulcer on his left heel in 1959. In I96I a free skin graft had been applied with ulceration of this area in a short period of time. In the same year, a cross thigh-flap was applied which ulcerated within two months of its application. The ulcer had persisted, gradually increasing in size and depth. Since 1959 he had experienced no sensation in his left foot. The past history had indicated that he had been treated for syphilis some 3 years previously. The patient was seen for the first time in October 1965. Neurological investigations suggested that this was a peripheral neuropathy below the left knee, probably of luetic origin. Examination of the ulcer of the left heel revealed an indolent ulcer. The base of this ulcer revealed slough overlying the os calcis region, while the edges of the ulcer were indurated, undermined and the surrounding skin was covered by callosities (Fig. 3). Sensation in all its forms was absent over the entire heel, the sole of the foot and the toes, except for normal sensation over the plantar surface of the phalanges of the big toe extending as far
NEUROVASCULAR ISLAND FLAP FIG. 3 Indolent recurrent neurotrophic heel ulcer. FIG. 4 FIG 5 Fig. 4.--Island flap from plantar surface of big toe isolated on neurovascular pedicles. Fig. 5. - - I s l a n d flap rotated over heel ulcer, big toe disarticulated at M P joint. 2D I45
146 BRITISH JOURNAL OF PLASTIC SURGERY as the metatarso-phalangealjoint region. In this isolated area the patient was able to appreciate pin prick and light touch sensation. In view of these clinical findings and the failure of free skin grafting, as well as the application of flaps, it was felt justifiable to carry out an island flap utilising the skin from the big toe region which was endowed with all modalities of sensation. The possibility or necessity of amputation of the leg presented the other alternative. Operative procedure, I6th October I965.--The procedure was carried out under the bloodless field technique. The ulcer was widely excised in circumference and in depth down to the periosteum overlying the region of the os calcis. An incision was then made on the medial aspect of the plantar surface of the foot extending from the medial aspect of the base of the heel FIG. 6 Island flap consolidated over heel, two and a half years after surgery. to the metatarso-phalangeal joint level of the big toe. The flaps were dissected and the medial plantar neurovascular bundle was identified in the interval between the abductor hallucis and flexor digitorum brevis muscles. Dissection proceeded distally, identifying the isolated neurovascular bundle to the medial side of the big toe and the plantar metatarsal neurovascular bundle to the adjacent sides of the big toe and the second toe. The skin and subcutaneous tissue overlying the phalanges and the metatarso-phalangeal joint was isolated on these neurovascular pedicles (Fig. 4). The neurovascular island flap was rotated into the heel defect and sutured into position. The big toe was disarticulated through the metatarso-phalangeal joint with dorsal skin providing the necessary flap cover to the amputation stump (Fig. 5)- A below knee plaster of Paris cast was applied after releasing the tourniquet and establishing that the flap was fully viable. Post-operative Course.--The circulation in the flap remained excellent while the patient appreciated sensation in the flap though this was referred to the big toe. The post-operative complication encountered was that of a breakdown of the incisional wound extending down along the plantar surface of the foot. This subsequently healed uneventfully. The island flap remained well consolidated, well vascularised and sensation in all its modalities continued to be appreciated (Fig. 6). There has been no subsequent recurrence of the ulceration of this area. The heel has remained firmly healed since the operative procedure, the patient being able to walk normally after being fitted with a boot.
NEUROVASCULAR ISLAND FLAP I47 DISCUSSION The cause of trophic ulceration in a weight-bearing area is thought to be due to repeated mechanical trauma associated with nerve dysfunction. Trauma, such as weight-bearing and inability to appreciate constant pressure, will lead to trophic ulceration of the heel. Subsequent ischaemia may possibly be a factor, but this would hardly appear to be a major factor since in excising these ulcers there is always an abundance of local blood supply in the area. The tendency to recurrent ulceration, breakdown of free skin grafts, distant flaps and local flaps may well be due to the fact that none of these grafts or flaps provides the anaesthetic area with sensation. The same factors which initiauy produced the ulceration of the heel are still fundamentally present, though skin cover has been provided. The island flap, by virtue of its ability to endow sensation which is appreciated by the patient, would seem to overcome this tendency to recurrence. Surgeons faced with the problem of neurotrophic ulceration of the heel will testify to the tendency for recurrent ulceration, despite well applied grafts and carefully planned flaps. This inherent quality of breakdown over weight-bearing surfaces is invariably associated with the loss of sensation rather than the decreased vascularity. The introduction of tissue, which is durable and carries with it both its btood and nerve supply, should to a large extent reduce the incidence of recurrence. It should be fully appreciated that the use of the island flap should in no way supersede the usual approach to the treatment of indolent heel ulcers. Conservative measures, the application of free skin grafts, local flaps from the " silent " area of the foot, cross foot-flaps and cross leg-flaps must remain the keystones of therapy, for in the vast majority of cases the entire skin of the foot, including the toes, lacks sensation. Snyder and Edgerton (I965) have reported the use of the island flap in two cases, while Moberg (I964) has illustrated a case with excellent results. There is every reason to believe that extensions of this technique will be devised and utilised. Theoretically and practically, any one of the toes could be utilised as in the case of the hand. Skin grafts may be applied to the donor soft tissue defect, making ablation of the donor area unnecessary. In this particular case there did not appear to be any vascular abnormality as reported in the case of Snyder and Edgerton (I965), but this abnormality must certainly be borne in mind as advised by these authors. It is also considered that the neurovascular bundle is more easily isolated as it emerges in the interval between the abductor hallucis muscle and the flexor digitorum brevis muscle. This of necessity means that an incision has to extend right from the base of the heel as far as the metatarsal head region. The island flap, though limited in its application, should therefore always be considered in the treatment of neurotrophic ulceration of the heel, since it may well spell the difference between salvage and ablation of the leg. SUMMARY i. In the vast majority of cases of trophic ulceration of the heel, the entire plantar surface of the foot and toes is anaesthetic. Conventional methods of treatment, both conservative and surgical, such as the application of free grafts, local flaps, cross foot-flaps or cross leg-flaps remain the keystone of treatment in attempting to provide adequate skin cover to this area. 2. In isolated instances, however, it is possible to have an area of intact sensation overlying the plantar surface of the individual toes as well as the region of the metatarsal
148 BRITISH JOURNAL OF PLASTIC SURGERY heads. The use of the island flap technique is these instances will offer an added method of surgical treatment of indolent ulceration of the heel. 3. One case is presented, showing the failure of the conventional methods of treatment and the use of the island flap to the heel in obtaining healing and prevention of subsequent recurrence. REFERENCES (;ray's Anatomy (1942). Edited by Johnston, T. B. and Whillis, J., e8th ed., pp. 800 and II37. London : Longmans, Green. MOBERG, E. (1964). Surg. Clins N. Am. 44, IOI9. LITTLER, J. W. (196o). Trans. int. Soc. plast. Surg., 2nd congr. 1959, p. 175. Edinburgh: Livingstone. SNYDER, G. B. and EDGERTON, M. T. (1965). Plastic reconstr. Surg. 36, 518. TUmANA, R. (196o). Proceedings of Symposium held at Glasgow, 7th April, by The Hand Club and Second Hand Club at the British Orthopaedic Association.