High and dehiscent jugular bulb: clear and present danger during middle ear surgery.

PURPOSE: Internal jugular vein is anatomic continuation of cranial dural sinuses in the neck region. During the course of skull base the first enlarged segment of jugular vein is described as jugular bulb. The aim of this study is to evaluate the jugular bulb abnormalities and define the risk of high and dehiscent jugular bulb injury during middle ear surgery. METHODS: This is a retrospective radiologic study of 1,010 patients (2,020 temporal bones) with various ear symptoms who had high resolution temporal bone computed tomography scans between 2007 and 2011. RESULTS: High jugular bulb was seen in 308 (15.2 %) temporal bones. Jugular bulb dehiscence was encountered in 153 (7.5 %) temporal bones. High jugular bulb and jugular bulb dehiscence were more common in the right ears and females. Forty-one (2 %) temporal bones revealed high and dehiscent jugular bulb which can be vulnerable during middle ear surgery. High and dehiscent jugular bulb was more common in the right ears and males. Male predominance becomes more significant in the left ears. Of the 308 temporal bones with high jugular bulb, 87 (28.2 %) also had coexisting carotid canal dehiscence. CONCLUSION: High and dehiscent jugular bulb is an important anatomic variation that can result in catastrophic outcomes during middle ear surgery. Our series show that 2 % of patients can be considered in the "high-risk" group. Precise assessment of the preoperative computed tomography scans by both the radiologist and the ENT surgeon is of utmost importance. Preoperative awareness will minimize morbidity and mortality.