First dorsal interosseous muscle transfer to restore opposition of the new thumb after index pollicization: anatomical description of an original technique and case report

Index pollicization in severe thumb hypoplasia or aplasia in children or for the reconstruction of a mutilated thumb in adults is a rare and technically demanding procedure. Weakness of the new thumb is routinely reported after index pollicization. An inappropriate position of the first dorsal interosseous muscle (FDIM) can partly explain this strength deficit. Here, we report an original anatomical study on FDIM transfer for reanimation of the new thumb's opposition function and its clinical application. An anatomical study was carried out on three upper limbs from fresh, non-embalmed adult cadavers. We demonstrated the feasibility of an FDIM transfer pedicled on the proper FDIM artery and the deep branch of the ulnar nerve. The proximal FDIM insertions were sutured to the lateral border of the flexor retinaculum to recreate the superficial thenar musculature. This procedure was performed on a 52-year-old man who was referred to us with swelling on his hand. We discovered a myxoid inflammatory fibroblastic sarcoma of the thumb that required proximal thumb amputation while preserving the base of the first metacarpal. To our knowledge, this is the first description of FDIM pedicled flap transfer during an index pollicization procedure among an adult population. However, in severe thumb hypoplasia or aplasia cases, this procedure is limited by the size and anatomical variations of the neurovascular structures among a population affected by radial longitudinal deficiency.

Pollicization in the treatment of congenital severe hypoplasia and aplasia of the thumb: a systematic review

Pollicization of the index is the treatment of choice for severe hypoplasia and aplasia of the thumb. After a historical overview, we present a systematic review of this procedure. The main steps of this procedure were reported by Dieter Buck-Gramcko in 1971 and are still relevant nowadays. Many refinements have been described over the last decades by different surgeons to address limitations related to bone stock, musculotendinous structures and skin incisions. However, considering the complexity of this procedure and the results in the literature, the functional and esthetic outcomes can still be improved thanks to basic research. Pollicization of the index is rarely done and is one of the most demanding surgical procedure in hand surgery.