Revision Surgery Through a Plantar Approach for Recurrent Interdigital Neuroma

Recurrent or persistent pain in the intermetatarsal space following excision of a Morton neuroma

Exclusion of other sources of forefoot pain

Transient relief from a focal injection of lidocaine

A patient will have focal pain on the plantar aspect of the foot, over the stump of the nerve, usually in the second or third intermetatarsal space.

If the pain and tenderness are in more than one intermetatarsal space, or in both feet, the diagnosis of a neuroma is unlikely.

Percussion over the nerve may reproduce symptoms and cause dysesthesias in the nerve distribution. This is not always the case. Often there is only deep pain with direct pressure over the nerve end, which is less definitive and may be from another diagnosis.

It is important to assess the length of the initial incision. Did the previous incision extend sufficiently proximal to allow transaction of the nerve in a non–weight-bearing part of the foot?

Exclude subluxation or synovitis of the adjacent metatarsophalangeal joints (especially the second), Freiberg infraction, a stress fracture of the metatarsal, metatarsalgia, inflammatory or degenerative arthritis, tarsal tunnel syndrome, and complex regional pain syndrome. An adjacent neuroma, although possible, is highly unusual.

An injection of 0.5 mL of lidocaine in the area of maximal pain at the stump of the nerve should provide near-complete relief of symptoms for at least 1 hour. Use a 25-gauge needle. Without this confirmation of the diagnosis, it is highly unlikely that a revision surgery will have a successful outcome.

Standing anteroposterior/lateral and both oblique radiographs of the forefoot will help exclude other diagnoses, as will magnetic resonance imaging. Ultrasonography may have a diagnostic role.

A stump neuroma will be found proximal to the metatarsal head ( Fig. 19.1 ).