Selective resection of the cavernous sinus medial wall in functional pituitary adenomas: opening the gate to the cavernous sinus from medial to lateral

OBJECTIVE: Surgical management of functional pituitary adenomas (FPAs) presents significant challenges, especially when cavernous sinus (CS) invasion restricts tumor resection and decreases postoperative hormonal remission rates. The aim of this study was to further elucidate the role and effectiveness of medial wall of the CS (MWCS) resection in treating tumors that extend into the CS. METHODS: The authors retrospectively reviewed patients with hormone-secreting PAs who underwent endoscopic endonasal transsphenoidal surgery at a single center. All patients underwent MWCS resection to remove tumor within the medial wall and facilitate complete CS resection. Clinical, radiological, and endocrine outcomes were assessed. RESULTS: Thirty-five patients (26 female, mean age 43 years), with a mean maximum tumor diameter of 1.4 cm, were monitored from 4 to 33 months. Among them, 19 had acromegaly, 14 had Cushing's disease, and 2 had thyrotropin-secreting adenomas. Patients were classified according to Knosp grades as follows: 7 (20.0%) with grade 1, 18 (51.4%) with grade 2, 9 (25.7%) with grade 3, and 1 (2.9%) with grade 4. Early endocrine remission was achieved in 32 of 35 patients (91.4%), with 3 patients requiring postoperative medical therapy and/or radiation therapy. Complications included transient central diabetes insipidus (n = 5), hypopituitarism (n = 5), and abducens nerve palsy (n = 1), all of which resolved without permanent deficits. There were no incidents of internal carotid artery (ICA) injury, CSF leakage, or infection. No recurrences or hormonal relapses were observed during the follow-up period. CONCLUSIONS: With a solid understanding of local anatomy, MWCS resection can be performed safely and effectively, offering several surgical advantages. These include complete removal of tumor tissue embedded within the medial wall; direct access to the superior, posterior, and inferior compartments of the CS, allowing for more radical resection of tumors invading these compartments; greater lateral mobilization of the parasellar segment of the ICA; and enhanced lateral ICA mobilization, improving exposure of tumors involving the CS's superior-posterior and even lateral compartments of the CS. Overall, MWCS resection might improve surgical outcomes and endocrine remission in selected patients with FPA.