The Versatility of the Supinator to Posterior Interosseus Nerve Transfer: Indications and Outcomes-A Case Series.

Abstract

Background: Transfer of the supinator motor branches to the posterior interosseous nerve (SPIN) was first described as a reliable method of restoration of digit extension in cases of paralysis when there is retained function in the 5th and 6th cervical nerve roots with loss of function in the 8th cervical nerve root.

Methods: The authors performed a retrospective review of all SPIN transfers that were performed in their unit over a 6-year period, which included 16 limbs of 14 patients. The median age was 49 years (range, 22 to 74 years). The average follow-up period was 15 months (range, 6 to 24 months). The pathogenesis included spinal cord injury (SCI) in 5, plexus root avulsion in 3, degenerate spondyloradiculopathy in 3, paralysis from oncologic resection in 1, inflammation in 1, and compressive neuropathy in 1.

Results: Functional digit extension (Medical Research Council grade 3 or above) was achieved in 12 of 16 limbs. Patients with degenerative spinal lesions had the worst outcome, with a median of Medical Research Council grade 2, and a median time to surgery of 20 months (average age, 67 years), compared with 13 months in the SCI group (average age, 32.8 years) and 4 months in the brachial plexus injuries group (average age, 34.6 years).

Conclusions: The SPIN transfer may be performed safely in a wide spectrum of pathologies, including brachial plexus injuries, SCIs, and neuritis. However, in degenerative spondyloradiculopathy, inferior outcomes were obtained, which may be due to late referral, chronic denervation, possible involvement of the donor nerve, an older age group, or potentially diminished rehabilitation and neural plasticity potential.

Clinical question/level of evidence: Therapeutic, IV.