2025 Proffered Presentations
S001: THE ROLE OF RESECTING THE MEDIAL WALL OF THE CAVERNOUS SINUS WALL IN OPTIMIZING HORMONAL OUTCOMES FUNCTIONING PITUITARY ADENOMAS
Prakash Nair, MCh, Neurosurgery; Ashutosh Carpenter; Akhilesh Gowda, MCh, Neurosurgery; Sanjay HM; Antony Stanley; Easwer HV; Jayanand Sudhir B; Sree Chitra Tirunal Institute for Medical science and Technology, Trivandrum, Kerala, India
Introduction: Microscopic invasion of the medial cavernous sinus wall (MCW) by functional pituitary adenomas (FPA) significantly impedes achieving hormonal remission post-surgery. The modified Knosp grading system (KS) for cavernous sinus (CS) invasion, based on MR imaging, may not accurately assess the extent of CS involvement in FPA [1]. A detailed anatomical description and technique for MCW resection have been recently introduced [2]. This retrospective study evaluates the surgical outcomes of MCW resection in FPA patients.
Methods: A retrospective analysis was conducted on FPA cases with MCW resection by the endoscopic endonasal approach (EEA) performed between January 2021 and December 2023. Preoperative CS involvement was assessed using the KS. MCW resection was performed when it appeared infiltrated by FPA on direct endoscopic inspection. Resected MCW samples were evaluated for microscopic tumour infiltration, and histopathological findings were compared with direct endoscopic assessment and KS to predict CS involvement. Statistical analysis was performed to assess the accuracy of MCW involvement by direct endoscopic inspection compared to KS.
Results: EEA was performed on 223 patients for pituitary tumours; 40 patients had FPA. MCW resection was performed in 25 patients with suspected CS involvement based on endoscopic inspection. GH-secreting tumours were the most common (48%), followed by ACTH (36%) and PRL-secreting tumours (4%). The overall hormonal remission rate post-surgery was 80%, with remission rates of 88.9% for first-time surgeries and 57.1% for repeat surgeries. Transient lateral rectus palsy occurred in 2 patients. A CSF leak occurred in one patient, managed by endoscopic repair and lumbar drainage. There were no cases of ICA injury or mortality. The mean surgical time was 224 minutes. The distribution of KS among patients was: KS 0 (4%), KS 1 (8%), KS 2 (32%), KS 3A (36%), KS 3B (8%), and KS 4 (12%). Microscopic tumour infiltration was seen in 19/25 (76%) MCW samples. When the positive MCW was compared to the KS, we found that MCW involvement was seen in KS 1 (50%), KS 2 (75%), KS 3A (88.8%), KS 3B (100%), and KS 4 (100%). The sensitivity and specificity of direct endoscopic inspection for MCW invasion were 95% and 75%, respectively. ROC curve analysis demonstrated that direct endoscopic visualisation is a significantly better predictor of CS involvement than KS, with an AUC of 0.850 indicating good discriminative ability. These findings suggest that KS is unreliable for detecting CS involvement in KS 1 and 2, though a larger study is needed to confirm these results.
Conclusion: MCW resection in FPA cases with suspected CS involvement yields higher hormonal remission rates. Knosp grading underestimates CS invasion, while endoscopic inspection provides greater accuracy in predicting MCW invasion by the tumour.
References:
[1] Micko, A et al. Invasion of the cavernous sinus space in pituitary adenomas: endoscopic verification and its correlation with an MRI-based classification. J. Neurosurg. 122, 803–11 (2015).
[2]Truong, H. Q. et al. The medial wall of the cavernous sinus. Part 1: Surgical anatomy, ligaments, and surgical technique for mobilization and/or resection. J. Neurosurg. 131, 122–30 (2018)
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