Imaging of Facial Nerve With 3D-DESS-WE-MRI Before Parotidectomy: Impact on Surgical Outcomes
Han‐Sin Jeong, Yi Kyung Kim, Hyung‐Jin Kim, Hak Jung Kim, E. Kim, Sook‐Young Woo, Man Ki Chung, Young‐Ik Son
Abstract
Objective:The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state waterexcitation sequence magnetic resonance imaging (3D-DESS-WE-MRI).However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored.We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI.Materials and Methods: This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors.Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients.FN visibility and tumor location relative to FN on 3D-DESS-WE-MRI were evaluated in 120 patients.Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors. Results:The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESS-WE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively.The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases.Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64-8.25]and 2.02 [95% CI: 0.32-12.90],respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19-16.75]and 1.94 [95% CI: 0.20-18.49],respectively).Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001). Conclusion:Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy.This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.