Management of High Jugular Bulb in Retrosigmoid Surgery for Vestibular Schwannoma: Analysis of 590 Consecutive Cases

BACKGROUND AND OBJECTIVES: High jugular bulb (HJB) is an obstacle when performing retrosigmoid intradural temporal drilling for resection of the meatal part of vestibular schwannomas. Some studies reported the technical nuance of the HJB management; however, the indications, impact on surgical outcomes, and long-term outcomes of this challenging management have not been fully analyzed. This study aimed to investigate the clinical and imaging characteristics of patients requiring the intraoperative HJB management, its impact on surgical outcomes, and long-term postoperative follow-up results. METHODS: After excluding patients with neurofibromatosis type 2 and those undergoing reoperation, 590 consecutive patients undergoing surgery for vestibular schwannoma were retrospectively investigated. Patients with HJB who required the intraoperative HJB management were compared with those with HJB who did not require the management and with a control group of patients without HJB. RESULTS: Of the 590 patients with vestibular schwannoma, 123 (21%) had HJB, and 23 (3.9%) required the HJB management. In patients requiring the HJB management, the jugular bulb tended to be positioned higher than the lateral semicircular canal and midline of internal auditory meatus. The jugular bulb apex tended to be closer to the surface of the petrous bone in patients requiring the HJB management, and the cutoff distance was 3.3 mm. There were no statistically significant differences in tumor removal rates or retreatment rates, and the sigmoid-jugular venous system remained patent in all 3 groups. CONCLUSION: The HJB management should be considered when the HJB apex is located at a high position, and the distance between the HJB apex and the surface of the petrous bone is close. Our study demonstrated that the HJB management can be performed safely during drilling of the internal auditory meatus, achieving effective tumor resection without causing venous complications.