Resident NYU Langone New York, New York, United States
Introduction: Intraoperative MRI (iMRI) has been shown to increase extent-of-resection and rates of gross-total-resection (GTR) in patients undergoing endoscopic endonasal approach (EEA) for pituitary macroadenomas. However, its role in the microadenoma resection remains unclear. In this retrospective study, we analyzed our departmental experience with iMRI to evaluate rates of GTR in EEA for pituitary microadenomas.
Methods: All patients who underwent EEA for pituitary microadenomas ( < 1cm in diameter) from 2013-2022 were included. GTR was defined as having no residual tumor on 6-month follow-up MRI. Chi-square tests with Yates’ continuity correction were performed on categorical variables and statistical significance was set at p< 0.05.
Results: There were 43 patients in the cohort. The median age was 39 (range 20-66) and 34 (79%) patients were female. 18 (42%) patients underwent iMRI and 25 (58%) patients did not. 37 (85%) were hormone-secreting microadenomas (16 prolactin, 15 ACTH, 6 growth hormone). There was no significant difference in tumor volume (p=0.13) or patient age (p=0.90) between the groups. In the iMRI group, 3 (17%) had possible tumor residual that warranted reexploration of the surgical cavity. In all 3 cases, additional tissue was resected, although no tumor was found on pathological analysis. Patients with iMRI had greater rates of GTR at 6-month follow-up than patients who did not (n=18, 100% vs n=21, 84%), though this difference did not reach significance (p=0.21). There was no difference in 30d reoperation rates between iMRI and non-iMRI groups (5.6% vs 4.0%, p=1)
Conclusion : Rates of GTR after EEA for microadenomas were higher in patients who had iMRI, although this difference was ultimately not statistically significant. While iMRI can potentially help identify small areas of residual among pituitary microadenomas, such residuals are often difficult to distinguish from postsurgical changes. Larger studies are needed to better understand the value of intraoperative imaging for microadenoma surgery.
