[High jugular bulb and its relationship with acoustic neurinoma surgery].

The jugular bulb is formed by the junction of the sigmoid sinus, inferior petrous sinus and the jugular vein. It is housed in the jugular fossa of the petrous pyramid. Variations in its size, location and relationship to the internal acoustic canal (IAC) have been reported. When the jugular bulb is located medial and less than 2 mm from the posterior wall of the internal acoustic canal, it is named as high jugular bulb. If the surgeon is not aware of this variation, damage to this structure can result in profuse haemorrhage and air embolism. This anatomical change also makes difficult the access to the intracanalicular portion of acoustic neurinomas when these tumours are excised by a retrosigmoid approach. We present the case of a patient with an acoustic schwannoma in whom a preoperative axial cranial CT revealed a high jugular bulb. To control this venous structure, we opened the IAC in a longitudinal manner achieving a total excision of the lesion preserving the function of the facial nerve. We conclude that preoperative radiological investigations in acoustic schwannomas surgery should include cranial MR and TC, to rule out the presence of a high jugular bulb. Cranial axial CT including bony windows and slices of 1.5 mm thick, should be carried out to exclude a high jugular bulb.