LAUSR

BACKGROUND Removal of the medial wall of the cavernous sinus (MW) remains a challenging obstacle for neurosurgeons. Here, we describe a practical method of endoscopic MW removal via endonasal transsphenoidal approach to minimalize intraoperative blood loss and postoperative morbidities. In addition, we present the pathological significance of this technique for functional pituitary adenomas (FPAs). METHODS We performed MW removal in patients with FPA with no well-defined pseudocapsule and a tumor in direct contact with the MW. The MW was judged to have tumor invasion based on the intraoperative appearance, and it was removed regardless of the appearance of MW involvement. The intraoperative findings and postoperative clinical, endocrinological and pathological outcomes were retrospectively reviewed. RESULTS A total of 14 patients underwent MW removal for FPA, including 12 patients with acromegaly and 2 with Cushing disease. The mean intraoperative blood loss was 170 ml (range, 32-400 ml), and none of the patients required blood transfusion. Among the 7 patients without intraoperative apparent MW involvement, 4 (57.1%) had pathologically confirmed tumor invasion into the MW (occult invasion). Biochemical remission by surgery alone was achieved in 13 patients (92.9%). Transient oculomotor palsy occurred in one patient (7.1%). CONCLUSIONS Occult tumor invasion into the MW was often detected in patients with FPA without a well-defined pseudocapsule but in direct contact with the MW. Our technique can enhance the effectiveness of surgery with minimal postoperative morbidities.