Enhancing nerve repair using artificial nerve conduits: A bridging technique without relying on the weak material property-A biomechanical study.

Abstract

Peripheral nerve injuries with extensive defects are often challenging to treat. Although second-generation collagen nerve conduit is a promising alternative to autologous nerve grafts, there are concerns about the limited early postoperative range of motion due to the conduit's weak material properties. This biomechanical study demonstrates the potential weakness of conventional suturing techniques in a nerve defect model using a collagen nerve conduit. We also investigated the effectiveness of a novel suturing technique, the suspension bridge method (SBM), which directly connects nerves using sutures without relying on the conduit strength. We used fresh chicken cadaver sciatic nerves to compare the maximum tensile strength of SBM using 2 sutures (group A) against traditional suturing methods using 2 and 3 sutures (groups B and C, respectively), and end-to-end neurorrhaphy with 2 sutures (group D). We also evaluated the mechanical properties by analyzing the stress-strain curves. Group A exhibited a significantly higher maximum failure load (1.32 ± 0.56 N) than group B (0.29 ± 0.05 N, p < 0.001) and group C (0.40 ± 0.10 N, p < 0.001), but not significantly higher than that of group D (0.96 ± 0.13 N, p = 0.056). The stress-strain curve showed steeper slopes in groups A and D than in groups B and C. Our results indicate that SBM offers an improved maximum failure load and better resistance to tension compared to traditional methods. This technique may be an effective alternative to conventional suturing methods using collagen nerve conduits.