High Variability of Outside Radiologist Reports in Trigeminal Neuralgia Patients Undergoing Endoscopic Microvascular Decompression

Objective: Preoperative MRI studies are routinely ordered as workup for patients with trigeminal neuralgia (TN). In this study, we catalog the incidence of neurovascular compression reported by “outside radiologists” on preoperative MRI imaging.

Methods: A retrospective review and analysis of operative videos, medical charts, and MRI imaging of endoscopic microvascular decompression (E-MVD) for TN. A 6-year interval review, from 2013 to 2019, yielded 186 consecutive patients undergoing E-MVD by a single surgeon for TN. Start date of 2013 chosen because of institution of centralized server for surgical video backup. Patients undergoing E-MVD for neoplasia were excluded. Patients without recorded operative videos or preoperative MRI’s read by a radiologist were excluded. Patient were initially categorized to have neurovascular compression or no compression based on operative video and chart review. Each group was then further categorized to either compression or no compression noted on preoperative MRI, as read by “outside radiologist.” Additional variables collected include: magnet strength (3/1.5 T), FIESTA/CISS/heavy T2-weighted imaging. Patients were offered surgery based on clinical characteristics (sharp, shooting, Burchiel’s criteria, medication refractory, etc.) and not based on radiology reports or preoperative MRI findings.

Results: Outside radiologists reported vascular compression in 65 (35%) of all patients who underwent E-MVD. They reported no vascular compression in 39 (21%) patients. Outside radiologists made no mention of having searched or analyzed the study for vascular compression in 82 (44%) patients. Use of higher strength magnet 3T did not influence radiologist reports of vascular compression (30 vs. 29%; n = 71 because most did not report type of magnet). Use of FIESTA/CISS sequences did improve likelihood of reporting vascular compression (65 vs. 35%; p < 0.05). Intraoperative neurovascular compression was noted in 183 (98%) patients, 4 (2%) patients had no discernable compression. None of the four patients without discernable compression had compression was found on preoperative MRI.

Conclusion: MRIs are routinely ordered preoperatively for patients with TN, largely to rule out other possibly pathologies causing TN. Overall, the frequency of radiographic neurovascular compression reported by outside radiologists is quite low, despite the very high intraoperative findings of neurovascular compression. In our study, we did not find a clear difference between 3T and 1.5T MRI but it does appear that dedicated FIESTA/CISS imaging significantly increases the frequency of neurovascular compression found on preoperative imaging.

No conflict of interest has been declared by the author(s).