Prevalence and determinants of recurrent laryngeal nerve injury after thyroidectomy: a Systematic Review and meta-analysis

Background Recurrent laryngeal nerve injury (RLNI) is a major complication of thyroid surgery and may lead to voice impairment and reduced quality-of-life. Aim This systematic review and meta-analysis sought to determine the frequency of temporary/permanent RLNI after different types of thyroid operations and to identify surgical and patient-related factors that influence risk. Methods PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar were searched in July 17, 2024. Eligible studies reported original data on RLNI after any type or approach of thyroidectomy in ≥20 patients. Risk of bias using RoB-2 for randomized trials and the Newcastle–Ottawa Scale for observational studies was done. Random-effects meta-analyses were performed. Subgroup and meta-regression analyses explored the effects of surgical type, method, approach, intraoperative nerve monitoring (IONM), hemostasis, drain use, and patient age on RLNI risk. Results: A total of 199 studies (304,352 patients) were analyzed. Transient RLNI was most frequent after completion thyroidectomy (10%, 95%CI, 4–16%) and hemithyroidectomy (8%, 95%CI, 1–15%), and least after near-total thyroidectomy (2%, 95%CI, 1–3%). Transoral and transcervical approaches had the highest transient RLNI rates (5%, 95%CI, 3–6%), while transaxillary had the lowest (1%, 95%CI, 1–2%). Permanent RLNI was highest in secondary thyroidectomy (2%, 95%CI, 1–3%). Meta-regression identified surgical approach, IONM use, hemostasis method, drain use, and patient age as significant determinant. Conclusions: Completion and revision surgeries, along with certain surgical approaches, increase RLNI risk. Tailoring surgical technique and optimizing intraoperative strategies are essential to minimize nerve injury. Systematic review registration https://www.crd.york.ac.uk/prospero/ , identifier CRD42024556259.