Microhook Nerve Connector Cable Grafting: A Cadaveric Study of Biomechanical Integrity

Cable grafting is a well-established technique for repairing major peripheral nerve defects but requires extensive microsurgical suturing, increasing operative time and foreign body burden at the coaptation. A novel microhook nerve connector (MNC), originally developed to improve surgical efficiency and repair alignment in direct coaptations, could offer a potential alternative to microsuture cable grafting. This study evaluated the biomechanical integrity of MNC cable grafting compared to traditional microsutures in a cadaver model. Our hypothesis is that cable-graft repairs using MNC will demonstrate greater holding strength than those repaired with microsutures.

After transection, 16 cadaveric nerves (5-6 mm diameter) were reconstructed through cable grafting with either an MNC or microsutures. Sixty-four smaller nerves (1.5-2 mm diameter) were cut to 3 cm length and assembled into 4-strand cable grafts. In the microsuture group, each strand was inset on both ends with two 9-0 nylon sutures. In the MNC group, each strand was positioned onto a single microhook column, secured, and wrapped in the small intestinal submucosa backing. Biomechanical integrity was assessed via tensile testing to determine load to failure.

MNC-assisted repairs exhibited significantly higher maximum load to failure than microsuture repairs (3.05 ± 0.57 N vs 1.55 ± 0.53 N). Both groups demonstrated sequential failure patterns, with MNC repairs sustaining significantly higher loads at each failure peak. Observationally, nerve strands from MNC repairs remained entubulated during sequential failure, temporarily maintaining the proximity of nerve ends.

MNC cable grafts demonstrated higher biomechanical holding strength overall and of each individual strand.

The MNC is a sutureless alternative to traditional microsuture cable grafting. These findings support further investigation of MNC-assisted cable grafting for clinical use in major peripheral nerve repairs.