'Inlay' Regenerative Peripheral Nerve Interface (RPNI) is superior to 'Burrito' RPNI for successful treatment of rat neuroma pain.

Treatment of painful neuromas has long posed a significant challenge for peripheral nerve patients. The Regenerative Peripheral Nerve Interface (RPNI) provides the transected nerve with a muscle graft target to prevent neuroma formation. Discrepancies in the RPNI surgical techniques between animal models (Inlay-RPNI) versus clinical studies (Burrito-RPNI) preclude direct translation of results from bench to bedside and may account for variabilities in patient outcomes. We compared outcomes of these two surgical techniques in a rodent model. Animals treated with the Burrito-RPNI after tibial nerve neuroma formation demonstrated no improvement in pain assessment, and tissue analysis revealed complete atrophy of the muscle graft with neuroma recurrence. By contrast, animals treated with the Inlay-RPNI had significant improvements in pain with viable muscle grafts. Our results suggest superiority of the Inlay-RPNI surgical technique for the management of painful neuroma in rodents.