Microhook Nerve Connector-Assisted Polyethylene Glycol Fusion for Immediate Restoration of Axon Continuity in a
Geetanjali S Bendale1, Andrew Azdell1, Jonathan Miller1
1Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University, Richmond, VA.
Purpose:
The purpose of the study was to test the efficacy of polyethylene glycol (PEG) fusion in restoring axon continuity when repaired with a microhook nerve connector (MNC) coaptation aid versus conventional microsutures. Our hypothesis was that the MNC would provide precise nerve alignment and stable coaptation and would support a higher percentage of axon fusion.
Methods:
In a rodent sciatic nerve model, transected nerves were either repaired with microsutures only (n = 12), microsutures with PEG (n = 12), or a MNC with PEG (n = 12). At initial surgery, PEG fusion was confirmed using electrophysiology. For 3 weeks, gait videos were used to calculate the sciatic function index. At the end of 3 weeks, compound muscle action potentials and muscle strength data were obtained. In a subset of animals, retrograde labeling was performed distal to the repair site and used to confirm successful axon fusion.
Results:
Polyethylene glycol fusion was confirmed in all animals from the two PEG groups. At 3 weeks, the sciatic function index values were similar between the three groups. The microsuture-only group did not show any detectable muscle contractions or the presence of intact motor axons. Retrograde labeling demonstrated that partial motor axon continuity had been re-established via PEG fusion in all 8/8 PEG fused animals, muscle contractions were preserved in 13/16, and measurable compound muscle action potentials were recorded in 21/24. However, there were no statistically significant differences between the microsuture + PEG and the MNC + PEG groups.
Conclusions:
In a small-diameter, direct-repair rodent model, at least some axons achieved PEG fusion. In this model, a MNC did not seem to improve PEG efficacy over suture-assisted PEG fusion.
Clinical Relevance:
Polyethylene glycol fusion either performed in conjunction with sutures or a MNC can, to a limited extent, restore axon continuity in cleanly transected, small-diameter nerves.
