Biomechanical Evaluation of a Novel Sutureless Hydrogel Device for Peripheral Nerve Repair

Following traumatic injury, nerve repair is essential to the restoration of muscle function and sensation. The current gold standard of nerve repair is microsuture repair, which requires trained microsurgeons to perform time-intensive and technically demanding procedures under high magnification. Microsuture repair suffers from inconsistent repair quality among surgeons and variable clinical outcomes. Neurorrhaphy sutures are non-resorbable and prone to fibrous tissue ingrowth and attendant foreign body reaction, both of which are believed to contribute to the observed shortfall in clinical outcomes. Here, we introduce a novel, sutureless, in situ forming, and fully degradable hydrogel coaptation device for nerve repair. The practical usability of the hydrogel device was assessed by procedure timing, tensile repair strength, and repair quality compared to the traditional microsuture approach. Human cadaveric nerves were used to perform hydrogel and suture repairs for comparison in a relevant model. Additionally, the hydrogel coaptation device was used for primary sciatic nerve repairs in rats to assess feasibility for use in nerve repair in vivo. We observed that hydrogel nerve repairs were performed nearly three times faster than microsuture repairs, without any significant difference in tensile strength when pulled to failure, and had favorable quality scores when blindly assessed by plastic surgeons. Histologically, the in vivo feasibility study showed nerve bridging visualized using H&E, neurofilament, and myelin staining. Our findings suggest the novel hydrogel coaptation device may serve as a potential alternative to suture repair, with features addressing several critical limitations inherent to microsuture and existing nerve repair methods.