British Journal o/Plastic Surgery (1988), 41,657-659 Q 1988 The Trustees of British Association of Plastic Surgeons

Case Report

Finger pulp reconstruction with plantar flap

T. INOUE, M. KOBAYASHI and T. HARASHINA

a free sensory medial

Departments of Plastic and Reconstructive Surgery, Saitama Medical Center, Kawagoe, and Keio University School of Medicine, Tokyo, Japan

Summary-This report describes the successful use of a free sensory medial plantar flap for the reconstruction of the volar skin of the index finger. Six months after the operation a corrective procedure was performed because the flap was bulky. A favourable result was obtained both functionally and aesthetically, with two-point discrimination of 4 mm, one year after reconstruction.

For finger pulp reconstruction the thenar flap or a free skin graft from the non-weight-bearing area of the foot are well established techniques. Altema- tively, a neurovascular island flap from another finger may be used for restoration of sensation. However, none of these methods is entirely satisfac- tory both functionally and aesthetically.

In recent years neurovascular free flaps have been used for finger pulp reconstruction. We have found that a free sensory medial plantar flap is a satisfactory technique for reconstruction of the volar defect of an index finger.

Case report

A 29-year-old man had the volar skin of his right index finger avulsed distal to the DIP joint due to an accident in a grinder; the bone was intact. The avulsed skin was sutured in its original position by a local practitioner but several days later the avulsed part of his index finger was necrotic and he was referred to our hospital (Fig. 1). A preoperative X-ray finding revealed an intact distal phalanx. At operation a complete debridement was performed, resulting in partial exposure of the volar surface of the phalanx. In order to restore sensation to this area a free sensory medial plantar flap was used.

The medial plantar flap, measuring 3 x 5 cm, was deslgned on the right sole (Fig. 2). The flap was raised without including the plantar fascia. The medial plantar artery and accompanying vein were prepared as the vascular pedicle and a branch of the medial plantar nerve was preserved to provide sensation. The neurovascular pedicle was about 2cm in length and the diameter of both artery and vein was about 1 mm (Fig. 3). The donor

site on the sole was covered with a split skin graft obtained from the ipsilateral leg.

A mid-lateral skin incision on the radial side of the injured index finger was extended proximally to expose the digital artery, its accompanying vein and the radial digital nerve (Fig. 4). Anastomoses between these dissected arteries, veins and nerves were performed using 1 l/O nylon sutures under the operating microscope. For stabilisation of the DIP joint, a Kirschner wire 1.2 mm in diameter was inserted from the tip to reach the metacarpus of the index finger. Postoperatively, prostag- landin El 120 mg IV bd was administered for the first 7 days.

The free medial plantar flap took completely and the patient was discharged 10 days after the operation. The Kirschner wire was extracted on the 14th postoperative day.

Sensation in the transferred medial plantar flap was restored and 6 months after operation two-point discrim- ination was 5 mm; the patient was completely satisfied with the result and experienced no inconvenience in daily activities. However, the flap was somewhat bulky and a corrective operation was performed at 8 months after the first operation. The flap skin was partially resected in a spindle shape for about 5 mm on the ulnar side. No decrease in sensation in the flap was detected postopera- tively and two-point discrimination was 4 mm one year after the first operation (Fig. 5).

Discussion

A free sensory medial plantar flap was first described by Morrison et al. (1983). .However, before that it was used as an instep fla.p for the

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BRITISH JOURNAL OF PLASTIC SURGERY

Fig. 1 Fig. 2

Fig. 5

Fig. 4

Figure l-Preoperative view; the avulsed skin was necrotic but the distal phalanx was intact. Figure 2-The medial plantar flap, measuring 3 x 5 cm, was designed on the sole of the right foot. Figure %-The free medial plantar flap, raised without including the plantar fascia. Figure 4-A complete debridement was performed and recipient vessels and nerve were dissected. Figure %-The final result one year after reconstruction (4 months after the thinning procedure), when the two-point discrimination was 4 mm.

reconstruction of the heel (Harrison and Morgan, 1981) with favourable results. The application of a free medial plantar flap to the palm was described by Sekiguchi et al. (1984) and they also obtained a successful result.

Reconstruction of finger pulp using a free medial plantar flap is advantageous in many ways. First, the skin of the instep closely resembles that of the volar side of the finger in that it has cuticle and it has therefore been used as the donor site for free skin grafts with favourable results in terms of both texture and colour match. Secondly, donor site morbidity is minimal because the resultant scar is not conspicuous and leaves no functional defect since the flap is obtained from the non-weight- bearing area. When a larger flap is required, some

complications such as hypo-aesthesia of the distal sole and/or a painful marginal scar may be left. However, a small flap of 3 x 5 cm, as in this case, is free from such complications.

Buncke and Rose (1978) described the free hemi- pulp flap obtained from the medial aspect of the big toe as a free sensory flap. They reported successful results with excellent two-point discrim- ination, as we have done, but our method has the advantage that the donor site is located in a non- weight-bearing area.

Although our flap is somewhat difficult techni- cally, we believe it is a satisfactory method of reconstruction of the palmar aspect of thumb and index finger since it provides satisfactory shape and sensation.

CASE REPORT: FINGER PULP RECONSTRUCTION WITH A FREE SENSORY MEDIAL PLANTAR FLAP 659

References

Buncke, H. J. and Rose, E. H. (1978). Free toe-to-fingertip neurovascular flaps. Basic and Rrconstructir~e Surgery, 63, 607.

Harrison, D. H. and Morgan, B. D. G. (1981). The instep island flap to resurface plantar defects. British Journal of‘ Plastic Surger>,. 34, 3 15.

Morrison, W. A., Crabb, D. M., O’Brien, B. M. and Jenkins, A. ! 1983). The instep of the foot as a fasciocutaneous island and as a free flap for heel defects. Plastic and Reconstructire Surgerv. 12, 56.

Sekiguchi, J., Kajiyama, K. and Kobayashi. S. (1984). Application of the free medial plantar fasciocutaneous sensory flap to the hand. Journal Sf‘Japanese Society for Surgery 01 the Hand. 1. 705.

The Authors

Takeo Inoue, MD, Assistant Professor, Department of Plastic and Reconstructive Surgery. Saitama Medical Center, Sai- tama Medical School, 1981 Kamoda, Tsujido. Kawagoe, 320 Japan.

Masahiro Kobayashi, MD, Assistant. Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, Tokyo.

Takao Harashina, MD, Professor, Department of Plastic and Reconstructive Surgery. Saitama Medical Center.

Requests for reprints to Dr Inoue.

Paper received 21 January 1988. Accepted 28 March 1988.