Jensen Tsun-Ki So

and 1 more

Introduction: The non-recurrent laryngeal nerve (NRLN) is a known anatomical variation of the normal recurrent laryngeal nerve (RLN). Its prevalence is estimated <1% and is prone to higher risk of iatrogenic injury. The risk of injury during thyroid surgery have been reported as variable in current literature, from 0% up to 12%. This study aimed to systematically review the incidence of NRLN injury and present the results through meta-analysis. The incidence of injury to NRLN and RLN was compared and analysed to determine its statistical significance. Methods: The PRISMA protocol was followed for an online search of prominent literatures. Studies were selected and excluded according to specific criteria. Quality assessment was performed, and data was extracted. Meta-analysis was conducted for the incidence of injury of the NRLN, and its comparison to the RLN. Results were presented in the form of a systematic review and discussed. Results: 17 studies were included in the final analysis. It was found that the pooled risk of NRLN injury was 7% and the risk ratio of injury in comparison to the RLN was 3.8, showing a statistically significant difference. Conclusion: This is the first study to report the overall risk of injury to the NRLN and found a statistically significant difference in comparison to the injury of RLN. This evidence provides grounds for future surgical guidelines to prevent injury to the NRLN. It is suggested that intra-operative nerve monitoring (IONM) should be performed in all patients found to have NRLN pre-operatively and intra-operatively.