Innervated Lateral Middle Phalangeal Finger Flap for a Large Pulp Defect by Bilateral Neurorrhaphy

Abstract

The dorsal middle phalangeal finger flap is a reliable flap. However, it requires skin grafting on the whole surface of the dorsum of the middle phalanx of the donor finger for an exposed extensor tendon and leaves a conspicuous contour deformity at the donor site. In an effort to overcome this problem, the authors have been using a heterodigital innervated lateral middle phalangeal finger flap for resurfacing sizable defects of the pulp. Flaps were designed on the lateral ulnar side of the middle finger for five thumb defects and the ring finger for two little finger defects. To provide sensation to the flap, one nerve fascicle from the direct small branches of the proper digital nerve after interfascicular dissection (palmar aspect of the flap) and the dorsal branch of the proper digital nerve (dorsal aspect) were identified and sectioned proximally, leaving a 1-cm nerve tail attached to the flap. These flaps provided sensate coverage with static two-point discrimination values of approximately 6 mm. Donor finger morbidity was minimal, and pulp sensation in donor fingers was normal in all cases. No donor finger cold intolerance was reported in this series. This described flap supplies glabrous skin of nearly normal sensibility. One nerve fascicle from the direct small branches of the proper digital nerve and the dorsal branch of the proper digital nerve were used for maximal sensation. Donor fingers are cosmetically better than those of dorsal middle phalangeal finger flaps because the grafted skin is hidden by an adjacent finger.