Authors (including presenting author) :
Chan SY(1), Yuen KY(2)
Affiliation :
(1) Department of Surgery, Tseung Kwan O Hospital, (2) Department of Surgery, Tseung Kwan O Hospital
Introduction :
Intra-operative nerve monitoring is currently adopted by up to 80% of head and neck surgeons and over 50% of general surgeons performing thyroidectomy surgery in USA. In spite of the popularity, contemporary role of IONM in thyroid surgery remains unclear. In a study on functional outcome after recurrent laryngeal nerve monitoring, Dralle et al identified primary thyroidectomy for cancer and re-operations as risk factors of RLN paralysis. These risk factors were coherent with findings in our thyroidectomy data of the past decade. We implemented use of intra-operative nerve monitoring on 3 specific groups of high-risk patients: thyroid cancer, thyrotoxicosis and re-operation thyroidectomy in January 2019. We collected data of the first 6 months and conducted analyses.
Objectives :
To compare early post-operative recurrent laryngeal nerve outcome between visual nerve identification (VNI) and intra-operative nerve monitoring (IONM) in high risk thyroidectomy operations including thyroid cancer, thyrotoxicosis and re-operation thyroidectomy.
Methodology :
All patients with pre-operative intact RLN function undergoing high risk thyroidectomy operations including thyroid cancer, thyrotoxicosis and re-operation between January 2018 and June 2019 were retrospectively evaluated. Patients were stratified into VNI and IONM groups for comparison. All patients with pre-operative RLN palsy confirmed by endoscopy were excluded from the analysis. NIM 2.0/3.0 system® (Medtronic Xomed Surgical Products, Jacksonville, FL) was used for all cases with IONM. Stimulation was detected at 0.5-1.5mA. Demographic information, type of operation (hemithyroidectomy / re-operation / total thyroidectomy) and nature of thyroid disease were assessed. Post-operative assessment was performed for clinical hoarseness as reported by patients prior to discharge and on clinical follow ups at 2-8 week intervals. All patients with subjective hoarseness had flexible laryngoscopy assessment of RLN status on day 14-21 post-operation. Comparisons were conducted on clinical hoarseness, endoscopically confirmed post-operative RLN injury and operating time between the VNI group and IONM group. Subgroup analyses were carried out for the cancer group, thyrotoxicosis group and re-operation groups respectively.
Statistical Analysis: The data were analyzed using statistical package for social sciences (SPSS) software version 20.0. Categorical variables were analyzed by Chi-square (univariate) and binary logistic regression (multivariate) tests. The Fischer exact test was applied to assess the level of significance, wherever the values were 5 or less. A p value of < 0.05 was considered as statistically significant.
Result & Outcome :
Our data demonstrated that use of intra-operative nerve monitoring in selected high risk thyroidectomy surgery significantly reduced post-operative clinical hoarseness compared to routine visual nerve identification.
