Extended transsphenoidal approach for pituitary adenomas invading the cavernous sinus using multiple complementary techniques

Purpose: Transsphenoidal surgery is the treatment of choice for most pituitary adenomas (PA), except prolactinomas. Difficulties achieving radical resection with this method are encountered in patients with PAs invading the cavernous sinus (CS), due to the inability of the standard transsphenoidal approach to expose all tumors adequately. This study analyzed methods to resect PAs invading the CS and factors influencing the degree of tumor resection and occurrence of complications. Methods: Outcomes were retrospectively analyzed in 52 patients with PA invading the CS who underwent surgery via the extended transsphenoidal approach utilizing multiple techniques, including microscopy, endoscopy, neuronavigation, and intraoperative Doppler ultrasonography. Results: Gross-total resection (GTR) was achieved in 33 patients (63.5 %). GTR rate was significantly higher in patients with Knosp Grade 3 than Knosp Grade 4 (92.3 vs. 53.8 %) and in patients undergoing initial surgery than reoperation (77.1 vs. 35.3 %). One patient (2.9 %) undergoing initial surgery experienced transient cranial nerve palsy, without other postoperative complications. Postoperative complications were significantly higher after reoperation. Firm tumor consistency was significantly more frequent in patients undergoing reoperation than initial surgery (52.9 vs. 8.6 %). Conclusion: Extended transsphenoidal surgery incorporating multiple complementary techniques was highly effective for PAs invading the CS. Postoperative complications rates were relatively low, especially for patients undergoing initial surgery and those with Knosp Grade 3 tumors. Total resection of PAs invading the CS remains challenging, especially in patients undergoing reoperation or having firm tumors.