Resection of the medial wall of the cavernous sinus in functioning pituitary adenomas: Technical note and outcomes in a matched-cohort study

BACKGROUND: Parasellar dural invasion can be associated with treatment failure after excision of functioning pituitary adenomas. Because the medial wall of the cavernous sinus is a common site of microscopic disease, we hypothesize that its resection may lead to improvement in biochemical remission and recurrence rates. We aim to describe our technique in the resection of the medial wall of the cavernous sinus using binasal endoscopic transsphenoidal surgery (BETS); and compare tumor control and biochemical remission rates against a matched cohort. METHODS: Patients with functioning pituitary adenomas who underwent resection of the medial cavernous wall in addition to tumor excision via BETS were compared to a cohort matched for tumor type, size, and Knosp grade. Biochemical remission rates, tumor control at follow-up, and complication rates were assessed. RESULTS: Sixteen patients underwent resection of the medial wall of the cavernous sinus. Of 14 cases with wall specimens deemed adequate for histopathologic analysis, 43 % had microscopic evidence of tumor. Two of three patients with Knosp grade 0 scores had microscopic tumor invasion of the medial wall. The mean blood loss in the cohort was 175 mL (comparable to control, p = 0.895), with no operative complications noted. Gross total excision was achieved in 81 % of cases in the treatment cohort. At a median follow-up of 11 months, no statistical difference was noted in the biochemical remission and oncologic control rates between groups. CONCLUSION: Resection of the medial wall of the cavernous sinus is safe and technically feasible using BETS when performed by experienced surgeons. The Knosp classification may not be reliable for microscopic tumor invasion. The effect of this technique on clinical outcomes remains to be determined by larger cohorts with matched controls and long-term follow-up.