Background In this study, we evaluated the clinical efficacy of a biodegradable nerve conduit constructed of polyglycolic acid (PGA) tube with external and internal collagen scaffolding for digital nerve repair. Patients and methods A multi‐center registry study was conducted in 11 locations between July 2013 and May 2016. Multiple mechanisms of injury included clean‐cut (12 patients), crush (5 patients), and avulsion (3 patients) types of injuries. These patients underwent nerve repair with a biodegradable nerve conduit, with 9 patients having a primary repair and 11 patients having delayed repair. Average nerve gap was 16.7 mm (range: 1–50 mm). An average of 13 months follow‐up (range: 12–15 months) was available including sensory assessments. Results Improved s2PD was found with less severe injury as in clean‐cut (7.5 ± 1.5 mm), which was statistically significant in comparison to those in crush (9.8 ± 1.9 mm, P = .0384) and in avulsion (10.7 ± 4.7 mm, P = .0013) type injuries. A meaningful recovery (S3+ or S4) was observed in 90% of the 20 digital nerve repairs with a biodegradable nerve conduit of PGA with external and internal collagen scaffolding. Avulsion injuries had significantly lower levels of meaningful recovery (67%) in comparison to those of clean‐cut (P = .0291) and crush (P = .0486) types of injury. No adverse effects were reported postoperatively. Conclusion These results indicate that a biodegradable nerve conduit of PGA with external and internal collagen scaffolding is suitable for digital nerve repair of short nerve gaps with high levels of sensory recovery as measured by two‐point discrimination.

Background A basic fibroblast growth factor (bFGF) slow‐release system was combined to a biodegradable nerve conduit with the hypothesis this slow‐release system would increase the capacity to promote nerve vascularization and Schwann cell proliferation in a rat model. Materials and Methods Slow‐release of bFGF was determined using Enzyme‐Linked ImmunoSorbent Assay (ELISA). A total of 60 rats were used to create a 10 mm gap in the sciatic nerve. A polyglycolic acid‐based nerve conduit was used to bridge the gap, either without or with a bFGF slow‐release incorporated around the conduit (n = 30 in each group). At 2 (n = 6), 4 (n = 6), 8 (n = 6), and 20 (n = 12) weeks after surgery, samples were resected and subjected to histological, immunohistochemical, and transmission electron microscopic evaluation for nerve regeneration. Results Continuous release of bFGF was found during the observation period of 2 weeks. After in vivo implantation of the nerve conduit, greater endothelial cell migration and vascularization resulted at 2 weeks (proximal: 20.0 ± 2.0 vs. 12.7 ± 2.1, P = .01, middle: 17.3 ± 3.5 vs. 8.7 ± 3.2, P = .03). Schwann cells showed a trend toward greater proliferation and axonal growth had significant elongation (4.9 ± 1.1 mm vs. 2.8 ± 1.5 mm, P = .04) at 4 weeks after implantation. The number of myelinated nerve fibers, indicating nerve maturation, were increased 20 weeks after implantation (proximal: 83.3 ± 7.5 vs. 53.3 ± 5.5, P = .06, distal: 71.0 ± 12.5 vs. 44.0 ± 11.1, P = .04). Conclusions These findings suggest that the bFGF slow‐release system improves nerve vascularization and Schwann cell proliferation through the biodegradable nerve conduit.

Among various biomaterials, we focused on nanofiber-based polyglycolic acid (PGA) fabric and examined the dynamics of cells that migrate within the non-woven fabric after implantation. The efficacy of nano-PGA as a tissue reinforcement in the process of subcutaneous tissue repair was immunohistochemically investigated. Two types of

A major obstacle for tissue engineering ear-shaped cartilage is poorly developed tissue comprising cell-scaffold constructs. To address this issue, bioresorbable scaffolds of poly-ε-caprolactone (PCL) and polyglycolic acid nanofibers (nanoPGA) were evaluated using an ethanol treatment step before auricular chondrocyte scaffold seeding, an approach considered to enhance scaffold hydrophilicity and cartilage regeneration. Auricular chondrocytes were isolated from canine ears and human surgical samples discarded during otoplasty, including microtia reconstruction. Canine chondrocytes were seeded onto PCL and nanoPGA sheets either with or without ethanol treatment to examine cellular adhesion in vitro. Human chondrocytes were seeded onto three-dimensional bioresorbable composite scaffolds (PCL with surface coverage of nanoPGA) either with or without ethanol treatment and then implanted into athymic mice for 10 and 20 weeks. On construct retrieval, scanning electron microscopy showed canine auricular chondrocytes seeded onto ethanol-treated scaffolds in vitro developed extended cell processes contacting scaffold surfaces, a result suggesting cell-scaffold adhesion and a favorable microenvironment compared to the same cells with limited processes over untreated scaffolds. Adhesion of canine chondrocytes was statistically significantly greater (p ≤ 0.05) for ethanol-treated compared to untreated scaffold sheets. After implantation for 10 weeks, constructs of human auricular chondrocytes seeded onto ethanol-treated scaffolds were covered with glossy cartilage while constructs consisting of the same cells seeded onto untreated scaffolds revealed sparse connective tissue and cartilage regeneration. Following 10 weeks of implantation, RT-qPCR analyses of chondrocytes grown on ethanol-treated scaffolds showed greater expression levels for several cartilage-related genes compared to cells developed on untreated scaffolds with statistically significantly increased SRY-box transcription factor 5 (SOX5) and decreased interleukin-1α (inflammation-related) expression levels (p ≤ 0.05). Ethanol treatment of scaffolds led to increased cartilage production for 20- compared to 10-week constructs. While hydrophilicity of scaffolds was not assessed directly in the present findings, a possible factor supporting the summary data is that hydrophilicity may be enhanced for ethanol-treated nanoPGA/PCL scaffolds, an effect leading to improvement of chondrocyte adhesion, the cellular microenvironment and cartilage regeneration in tissue-engineered auricle constructs.

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