Anterior-posterior diameter is a key driver of resectability and complications for pituitary adenomas with suprasellar extension in endoscopic transsphenoidal surgery.

BACKGROUND: As endoscopic transsphenoidal approaches are more routinely selected for progressively larger pituitary adenomas with parasellar extension, understanding potential anatomical factors that limit resection and contribute to complications is becoming increasingly important for tailoring a surgical approach. This study aimed to reevaluate existing predictive tools for resectability in pituitary adenomas specifically with suprasellar extension, and furthermore identify any additional measurable features that may be more useful in preoperative planning. METHODS: A single-center retrospective chart review of adult patients who underwent endoscopic transsphenoidal surgery for pituitary adenomas with suprasellar extension from 2015 to 2020 was performed. Preoperative MRIs were systematically assessed to assign a Knosp classification, a Zurich Pituitary Score (ZPS), and for dimensional measurements of the suprasellar aspect of the lesions. Univariate comparisons and multivariate regression models were employed to assess the influence of these factors on extent of resection and postoperative complications. RESULTS: Of the 96 patients with suprasellar pituitary adenomas who underwent endoscopic transsphenoidal surgery, 74 patients (77%) had a gross total resection (GTR). Neither Knosp grade nor ZPS score, even when dichotomized, demonstrated an association with GTR (Knosp 3A-4 versus Knosp 0-2, p = 0.069; ZPS III-IV versus ZPS I-II, p = 0.079). Multivariate regression analysis identified suprasellar anterior-posterior tumor diameter (SSAP) as the only significant predictor of extent of resection in this cohort (OR 0.951, 95% CI 0.905-1.000, p = 0.048*). A higher SSAP also had the strongest association with intraoperative CSF leaks (p = 0.0012*) and an increased overall rate of postoperative complications (p = 0.002*). Further analysis of the regression model for GTR suggested an optimal cut point value for SSAP of 23.7 mm, above which predictability for failing to achieve GTR carried a sensitivity of 89% and a specificity of 41%. CONCLUSIONS: This study is unique in its examination of endoscopic transsphenoidal surgical outcomes for pituitary adenomas with suprasellar extension. Our findings suggest that previously established grading systems based on lateral extension into the cavernous sinus lose their predictive value in lesions with suprasellar extension and, more specifically, with increasing suprasellar anterior-posterior diameter.

Multicenter external validation of the Zurich Pituitary Score.

PURPOSE: Recently, the Zurich Pituitary Score (ZPS) has been proposed as a new quantitative preoperative classification scheme for predicting gross total resection (GTR), extent of resection (EOR), and residual tumor volume (RV) in endoscopic pituitary surgery. We evaluated the external validity of the ZPS. METHODS: In three reference centers for pituitary surgery, the ZPS was applied and correlated to GTR, EOR, and RV. Furthermore, its inter-rater agreement was assessed. RESULTS: A total of 485 patients (53% male; age, 53.8 ± 15.7) were included. ZPS grades I, II, III, and IV were observed in 110 (23%), 270 (56%), 64 (13%), and 41 (8%) patients, respectively. GTR was achieved in 358 (74%) cases, with mean EOR of 87.6% ± 20.3% and RV of 1.42 ± 2.80 cm3. With increasing ZPS grade, strongly significant decreasing trends for GTR (I, 92%; II, 77%; III, 67%; IV, 15%; p < 0.001) and EOR (I, 93.8%; II, 89.9%; III, 88.1%; IV, 75.4%; p < 0.001) were found. Similarly, RV increased steadily ([cm3] I, 0.16; II, 0.61; III, 2.01; IV, 3.84; p < 0.001). We observed intraclass correlation coefficients of 0.837 (95% CI, 0.804-0.865) for intercarotid distance and 0.964 (95% CI, 0.956-0.970) for adenoma diameter, and Cohen's kappa of 0.972 (95% CI, 0.952-0.992) for the ZPS grades. CONCLUSIONS: Application of the ZPS in three external cohorts was successful. The ZPS generalized well in terms of GTR, EOR, and RV; demonstrated excellent inter-rater agreement; and can safely and effectively be applied as a quantitative classification of adenomas with relevance to surgical outcome.

The Zurich Pituitary Score predicts utility of intraoperative high-field magnetic resonance imaging in transsphenoidal pituitary adenoma surgery.

BACKGROUND: It is currently unclear if there are subsets of patients undergoing transsphenoidal surgery (TSS) in which intraoperative high-field magnetic resonance imaging (3T-iMRI) is particularly advantageous. We aimed to investigate whether a radiological grading scale predicts the utility of 3T-iMRI in pituitary adenoma (PA) TSS. METHODS: From a prospective registry, patients who underwent endoscopic TSS for PA using 3T-iMRI were identified. Adenomas were graded using the Zurich Pituitary Score (ZPS). We assessed improvement after 3T-iMRI in terms of gross total resection (GTR), residual volume (RV), and extent of resection (EOR). RESULTS: Among 95 patients, rates of conversion to GTR after 3T-iMRI decreased steadily from 33% for grade I to 0% for grade IV adenomas, with a statistically significant conversion rate only for grade I (p = 0.008) and grade II (p < 0.001). All grade I adenomas were completely resected after 3T-iMRI. Median RV change was statistically significant for grades I to III, but not for grade IV (p = 0.625). EOR improvement ranged from a median change of 0.0% (IQR 0.0-4.5%) for grade I to 4.4% (IQR 0.0-9.0%) for grade IV, with a significant improvement only for grades I to III (p < 0.05). CONCLUSIONS: Interestingly, this study shows that clinical utility of 3T-iMRI is highest in the more "simple" adenomas (ZPS grades I-II) than for the more "complex" ones (ZPS grade III-IV). Grade I adenomas are amenable to GTR if 3T-iMRI is implemented. In grade III adenomas, EOR and RV can be improved to clinically relevant levels. Conversely, in grade IV adenomas, 3T-iMRI may be of limited use.