Electroactive biodegradable polyurethane significantly enhanced Schwann cells myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering.

When possible, direct repair remains the current standard of care for the repair of peripheral nerve lacerations. In large nerve gaps, in which direct repair is not possible, grafting remains the most viable option. Nerve scaffolds include autologous conduits, artificial nonbioabsorbable conduits, and bioabsorbable conduits and are options for repair of digital nerve gaps that are <3 cm in length. Experimental studies suggest that the use of allografts may be an option for repairing larger sensory nerve gaps without associated donor-site morbidity.

Peripheral nerve repair and reconstruction.

Purpose Reconstruction of peripheral nerve discontinuities with processed nerve allograft has become increasingly relevant. The RANGER Study registry was initiated in 2007 to study the use of processed nerve allografts in contemporary clinical practice. We undertook this study to analyze outcomes for upper extremity nerve repairs contained in the registry database. Methods We identified an upper extremity–specific population within the RANGER Study registry database consisting of 71 nerves repaired with processed nerve allograft. This group was composed of 56 subjects with a mean age of 40 ± 17 years (range, 18–86 y). We analyzed data to determine the safety and efficacy of processed nerve allograft. Quantitative data were available on 51 subjects with 35 sensory, 13 mixed, and 3 motor nerves. The mean gap length was 23 ± 12 mm (range, 5–50 mm). We performed an analysis to evaluate response-to-treatment and to examine sensory and motor recovery according to the international standards for motor and sensory nerve recovery. Results There were no reported implant complications, tissue rejections, or adverse experiences related to the use of the processed nerve allografts. Overall recovery, S3 or M4 and above, was achieved in 86% of the procedures. Subgroup analysis demonstrated meaningful levels of recovery in sensory, mixed, and motor nerve repairs with graft lengths between 5 and 50 mm. The study also found meaningful levels of recovery in 89% of digital nerve repairs, 75% of median nerve repairs, and 67% of ulnar nerve repairs. Conclusions Our data suggest that processed nerve allografts offer a safe and effective method of reconstructing peripheral nerve gaps from 5 to 50 mm in length. These outcomes compare favorably with those reported in the literature for nerve autograft, and exceed those reported for tube conduits. Type of study/level of evidence Therapeutic III.

Functional outcome following nerve repair in the upper extremity using processed nerve allograft.

https://lucris.lub.lu.se/ws/files/2247026/8862260

Chitosan-film enhanced chitosan nerve guides for long-distance regeneration of peripheral nerves

Artificial and non-artificial nerve grafts are the gold standard in peripheral nerve reconstruction in cases with extensive loss of nerve tissue, particularly where a direct end-to-end suture or an autologous nerve graft is inauspicious. Different materials are marketed and approved by the US Food and Drug Administration (FDA) for peripheral nerve graft reconstruction. The most frequently used materials are collagen and poly(DL-lactide-e-caprolactone). Only one human nerve allograft is listed for peripheral nerve reconstruction by the FDA. All marketed nerve grafts are able to demonstrate sufficient nerve regeneration over small distances not exceeding 3.0 cm. A key question in the field is whether nerve reconstruction on large defect lengths extending 4.0 cm or more is possible. This review gives a summary of current clinical and experimental approaches in peripheral nerve surgery using artificial and non-artificial nerve grafts in short and long distance nerve defects. Strategies to extend nerve graft lengths for long nerve defects, such as enhancing axonal regeneration, include the additional application of Schwann cells, mesenchymal stem cells or supporting co-factors like growth factors on defect sizes between 4.0 and 8.0 cm.

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Nerve grafting for peripheral nerve injuries with extended defect sizes

Purpose: As alternatives to autograft become more conventional, clinical outcomes data on their effectiveness in restoring meaningful function is essential. In this study we report on the outcomes from a multicenter study on processed nerve allografts (Avance 1 Nerve Graft, AxoGen, Inc). Patients and Methods: Twelve sites with 25 surgeons contributed data from 132 individual nerve injuries. Data was analyzed to determine the safety and efficacy of the nerve allograft. Sufficient data for efficacy analysis were reported in 76 injuries (49 sensory, 18 mixed, and 9 motor nerves). The mean age was 41 6 17 (18–86) years. The mean graft length was 22 6 11 (5–50) mm. Subgroup analysis was performed to determine the relationship to factors known to influence outcomes of nerve repair such as nerve type, gap length, patient age, time to repair, age of injury, and mechanism of injury. Results: Meaningful recovery was reported in 87% of the repairs reporting quantitative data. Subgroup analysis demonstrated consistency, showing no significant differences with regard to recovery outcomes between the groups (P > 0.05 Fisher’s Exact Test). No graft related adverse experiences were reported and a 5% revision rate was observed. Conclusion: Processed nerve allografts performed well and were found to be safe and effective in sensory, mixed and motor nerve defects between 5 and 50 mm. The outcomes for safety and meaningful recovery observed in this study compare favorably to those reported in the literature for nerve autograft and are higher than those reported for nerve conduits. V V C 2011 Wiley Periodicals, Inc. Microsurgery 00:000–000, 2011.

/pdf/processed-nerve-allografts-for-peripheral-nerve-5cdbf9nbwj.pdf

Processed nerve allografts for peripheral nerve reconstruction: a multicenter study of utilization and outcomes in sensory, mixed, and motor nerve reconstructions.

Ekkehard E. Bonatz

Papers

Processed nerve allografts for peripheral nerve reconstruction: a multicenter study of utilization and outcomes in sensory, mixed, and motor nerve reconstructions.