A Prospective Study of Intraoperative Neurophysiological Monitoring in Thyroid and Parathyroid Surgery at a Nigerian Teaching Hospital

Intraoperative neurophysiological monitoring (IONM) of the recurrent laryngeal nerve (RLN) during thyroid and parathyroid surgery has significantly reduced permanent voice complications in high-income settings, but its feasibility, outcomes impact, and cost implications in Nigerian academic surgical centres have not been studied. This dissertation prospectively investigates the implementation of IONM in thyroid and parathyroid surgery at a teaching hospital in Lagos, South West Nigeria, over a four-year period from 2019 to 2023. A prospective cohort of 200 patients undergoing thyroid or parathyroid surgery was divided into IONM (n=100) and non-IONM (n=100) groups based on institutional availability. RLN identification rates, temporary and permanent palsy rates, operative decision modifications triggered by IONM alerts, and total treatment costs were compared. IONM was associated with a significant reduction in temporary RLN palsy (4% versus 14%) and permanent palsy (0% versus 3%). Intraoperative IONM alerts prompted surgical strategy modification in 18% of monitored cases, preventing potential nerve injury. The incremental cost per complication avoided was estimated at USD 680, representing acceptable cost-effectiveness relative to the long-term productivity and quality of life impact of permanent RLN injury. The dissertation provides the first prospective IONM data from a Nigerian academic centre and recommends capital investment in IONM systems and structured training programs for endocrine surgeons in South West Nigeria. Keywords: intraoperative neurophysiological monitoring, recurrent laryngeal nerve, thyroid surgery, IONM, Nigeria