Cold Intolerance Following Digital Nerve Injury: A Multicenter Prospective Randomized Comparison of Decellularized Nerve Allograft Versus Nerve Conduits.

Background: Cold intolerance following digital nerve injury burdens patients significantly. To better understand how cold intolerance evolves in the setting of digital nerve injuries, a sub-analysis of a trial comparing conduit-based (CONDUIT) and processed nerve allograft (PNA) repairs was conducted. It was hypothesized that PNA repairs would alleviate cold intolerance more effectively, especially for longer nerve gaps.

Methods: A multicenter trial across 20 US-based medical centers was undertaken of patients 18- to 69-year-old presenting with 5 to 25 mm digital nerve gaps within 24 weeks of injury. Patients were randomized (1:1) to PNA or collagen CONDUIT repairs. Cold Intolerance Symptom Severity (CISS) scores and sensory function testers were assessed at first patient visit (FPV), 1-, 3-, 6-, 9-, and 12-months post-surgery, with patients and assessors blinded to treatment.

Results: In total, 220 patients were enrolled, with 183 patients included in final analysis with ≥6 months follow-up. At the last evaluable visit (LEV), mean CISS score decreased from FPV for both PNA (from 31.2 ± 27 to 20.8 ± 19) and CONDUIT (from 31.2 ± 30 to 25.9 ± 24). On sub-analysis, more patients converted from severe/extremely severe cold intolerance to mild cold intolerance for PNA compared with CONDUIT at 1 month and LEV (P < 0.05). The CISS scores correlated significantly with sensory function testing.

Conclusions: Although no correlation was demonstrated with nerve gap size, digital nerve gap repaired with PNA had significantly improved cold tolerance outcomes for patients with more severe cold intolerance at FPV relative to nerves repaired with CONDUIT.