The Role of Gap Length in Digital Nerve Reconstructions in the Upper Extremity with Processed Nerve Allograft
Timothy Niacaris, MD, PhD1; Mihir J Desai, MD2; Bauback Safa, MD3; Gregory M Buncke, MD3
1Department of Orthopaedic Surgery, JPS Health Network, Fort Worth, TX; 2Vanderbilt Orthopaedics, Nashville, TN; 3Buncke Medical Clinic, San Francisco, CA
Digital nerve injuries associated with hand trauma are common. Current reconstruction methods for addressing the zone of injury include nerve autograft, processed nerve allograft, and conduits. Outcomes studies assessing the influence of gaps lengths are limited due to the various challenges of this patient population. Data were queried from the on-going registry for digital nerve reconstructions with processed nerve allograft. We report on the return of meaningful sensation by gap length in digital nerve injuries.
The RANGER® Study is a multicenter IRB approved registry designed to collect data associated with processed nerve allografts (Avance® Nerve Graft, AxoGen, Inc). The registry database was queried for digital nerve repairs with a minimum of six months of quantitative follow-up. Demographics, nerve injury/repair, assessments, and safety were evaluated. Data included static/moving 2-point discrimination, Semmes-Weinstein Monofilaments, and tens score. The cohort was stratified into three groups according to gap length: Small(<15mm), Mid(15-29mm), and Long(>30mm). Meaningful recovery was defined as ? S3 on the MRC scale. Higher thresholds of recovery, defined at ?S3+, were evaluated in repairs with at least 1-year follow-up.
The cohort consisted of 175 injuries in 101 subjects. The mean patient age was 44±16years; patients were predominantly male. Concomitant injuries were reported in 92% of cases. The mean time-to-repair was 90±320days. Mean gap length was 19±11mm. The mean follow-up time was 387±203days. Overall meaningful recovery was reported in 95% of repairs with 93% reaching higher thresholds. Return of sensation was consistent across gap subgroups. Stratification by gap length is summarized in Table 1. No differences were observed by mechanism of injury, age, and time-to-repair. A trend for reduced recovery was observed in smokers (83%). No related adverse events were reported.
Processed nerve allograft can be used successfully for sensory nerve reconstruction. Overall meaningful recovery was reported in 95% of repairs. These outcomes were consistent for both short and long gap reconstruction. Higher levels of recovery were reported at similar levels in repairs with longer follow-up. Limitations of this study include the observational study design and lack of active control. These outcomes compare favorably to historical data in the literature for nerve autograft and exceed those for hollow tube conduit. No related adverse events or revisions were reported.
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