Comparison of conventional, revascularized, and bioengineered methods of recurrent laryngeal nerve reconstruction

Importance: Damage to the recurrent laryngeal nerve (RLN) is highly detrimental to voice, swallow, and cough. The optimal method for reconstitution of a nerve gap after injury is unknown. Objective: To evaluate multiple methods of RLN reconstruction. Design, Setting, and Participants: This study used an established canine model of RLN injury to examine purpose-bred, conditioned, female, 20-kg mongrel hounds atWashington University. A total of 32 dogs were examined, with 63 experiments performed. Interventions: Surgical transection or excision of the RLN with reconstruction by multiple methods. Main Outcomes and Measures: Six months after injury repair, laryngeal adductor pressures (LAPs), spontaneous and stimulable movement, and graft axon counts by histologic analysis were assessed. Results: Simple RLN transection with direct neurorrhaphy provided a mean (SD) recovery of 55.5%(12.5%) of baseline LAPs (P = .18 for comparison of LAP recovery among cases from the conventional nerve graft [39.4%(22.2%)]; P = .63 for comparison of LAP recovery among cases from the reverse autograft [60.8%(27.5%)]). Revascularized grafts provided a recovery of 54.5%(46.4%) while short and long acellular grafts provided recoveries of 60.4%(NA) and 39.5%(17.0%). Two of 11 polyglycolic acid reconstructions provided a measurable LAP with a mean (SD) recovery of 37.1%(8.9%) of baseline. Reconstruction with a neural conduit in any condition provided no measurable LAP recovery. Conclusions and Relevance: Conventional nerve grafting resulted in no significant difference in recovery of LAP function compared with simple neurorrhaphy or reverse autograft. Conventional and revascularized nerve grafts provided similar recovery. The use of bioengineered acellular nerve grafts or nerve conduits for reconstruction resulted in poor recovery of function.