Restoration of Sensation to an Insensate Hallux-to-Thumb Transfer

Reconstruction of the thumb with microsurgical transfer of the big toe is now an accepted approach. The expected outcome of such a procedure is a functioning digit, one that not only looks like a thumb, but moves like a thumb and transmits sensory information from the environment to the brain through its recovered sensibility. While the microsurgeon is well-versed in “take backs” to salvage vascular problems after such a complex reconstruction, there is nothing reported in the literature regarding salvage of the insensate hallux-to-thumb transfer.

A 43-year-old man was presented who had a hallux-to-thumb transferred successfully in March, 1999. By September, 2003, he had a thumb that had an excellent appearance, excellent range of motion at its interphalangeal joint, but still had no perception of touch on its dorsum, and only the perception of one-point moving and one-point static touch on its pulp. There was poor localization of these simple perceptions. At the initial operation, both plantar digital nerves had been connected to both digital nerves, but no dorsal neurotizations were done. Restoration of sensation was accomplished by resecting the in-continuity neuromas of the original two digital nerve reconstructions, and then reconnecting the two digital nerves across the 1.5-cm resultant defects with two bioabsorbable polyglycolic acid nerve conduits. Another 2.0-cm dorsal defect was reconstructed between the deep peroneal nerve located in the transplanted hallux with the radial sensory nerve. At 8 months after the neural reconstruction attempt, the patient had excellent localization of dorsal and “thumb” pulp static touch sensations. The patient received sensory re-education. The 15-month follow-up results for moving and static two-point discrimination were presented. This was the first salvage procedure for restoration of sensation reported for a hallux-to-thumb transfer.