American Society for Peripheral Nerve

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A Multicenter Study of Processed Nerve Allografts: Utilization and Outcomes in Mixed and Motor Nerve Repairs
Darrell Brooks, MD; Renata V. Weber; Jerome D. Chao, MD; Mickey Cho, MD; Christopher Wilson, MD; John Ingari, MD; Scott Wisotsky, MD; Bauback Safa, MD
Darrell Brooks, San Francisco, CA, USA

Introduction: Interest in alternatives to nerve autograft exist, however limited clinical data has been published on their use in mixed and motor nerve injuries. As such, a multicenter study was initiated to evaluate clinical outcomes of processed nerve allografts (Avance® Nerve Graft, AxoGen Inc.). We report a subgroup analysis from the outcomes data of observed safety and efficacy in mixed and motor nerve repairs.

Methods: Following IRB approval, utilization from the twelve participating centers and 25 surgeons resulted in 132 nerve injuries being contributed over a two year period. Data was collected on the injury, repair, safety and outcomes using standardized case report forms. A review and analysis of mixed and motor nerve repairs was completed. Quantitative and qualitative measures were reviewed and reported. Quantitative measures included: 2-point discrimination, MRCC scale for sensory and motor nerves, range of motion, strength testing and electromyography (EMG) studies. Qualitative measures included pain scoring and patient assessments. Analysis was performed and reported using descriptive statistics.

Results: Out of the 132 nerve repairs in the database, sufficient follow-up data was gathered for 76 injuries. Fifteen males and seven females with twenty-seven nerve repairs (eighteen mixed and nine motor) were identified. These included, median, ulnar, radial, musculocutaneous, facial, peroneal and axillary nerve. Their mean ± SD (minimum, maximum) age was 40 ± 20 (18, 86). Mean gap length was 29.1 ± 11.8 (10, 50) mm and the time to repair was 156 ± 212 (0, 725) days.

Twenty nerves demonstrated quantitative recovery and three showed qualitative recovery. The remaining four did not report recovery. In the repairs reporting MRCC scores, there were 3 (S3), 4 (S3+), 1 (S4), 6(M3), 5 (M4) and 4(M5). Static 2-PD ranged from 6 to 12 mm (n=3). EMG results completed in 3 motor repairs, all reported reinnervation into the target muscle. No adverse events were reported, however two revisions not related to the allograft were required.

Conclusion: Careful consideration should be given to multiple factors when repairing major peripheral nerves. In this subgroup, processed nerve allografts were shown to be a safe and effective option for repairing mixed and motor nerves when an alternative to autograft was preferable. Continuation of this study will provide additional clinical data to further support and define the expected outcomes of processed nerve allografts for the reconstruction of peripheral nerves.


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