LAUSR

Using the Retrosigmoid Approach in a Patient With a High Jugular Bulb: 2-Dimensional Operative Video Jugular bulb, located in the jugular fossa, is a spherical enlargement at the junction of the sigmoid sinus and internal jugular vein. Under normal circumstances, there are some variations in its height and position.1,2 High jugular bulb is diagnosed when it is above the level of inferior margin of cochlear base, and the incidence is approximately 6% to 63%. High jugular bulb is easily misdiagnosed as glomus jugular tumor,3 exhibiting bone invasion in highresolution computed tomography scan of the skull base. Generally, high jugular bulb is a congenital vascular variation, which may increase the difficulty when performing operations using the translabyrinthine approach.4-6 It is showed that high jugular bulb sometimes may influence the ear structures and cause dizziness and tinnitus in patients, which usually demands no surgical management.7,8 The existence of high jugular bulb may carry the risk of bleeding during cerebellopontine angle (CPA) tumor surgery using the retrosigmoid approach and increase the difficulty in the exposure of CPA tumor.9-11 In the literature, Rauch et al12 reported a case in which bleeding resulted from injury to high jugular bulb during surgical exposure of the internal auditory canal (IAC) through the suboccipital route and discussed their lessons in dealing with high jugular bulb under such kind of situations. Gupta et al13 described a safety area (between the high jugular bulb and the internal acoustic meatus) available for drilling the meatus. Akaishi et al14 in the surgery of CPA meningioma by the suboccipital retrosigmoid approach introduced that after tumor resection, the uneven surface of the bone under the tumor base was also removed using a diamond drill, and the high jugular bulb became visible through the thinned bone and not harassed. However, these above cases are different from the surgery presented in this video.15 The authors here showed us a very difficult case of vestibular schwannoma using the retrosigmoid approach with a high jugular bulb. They safely exposed the jugular bulb overlying the IAC using a highspeed drill and made proper displacement of jugular bulb by using a cottonoid patty, bone wax, and rubber sheet. After that, the authors would have sufficient space to remove the tumor inside the IAC.