Anterior ethmoidal artery emerging anterior to bulla ethmoidalis: An abnormal anatomical variation in Waardenburg's syndrome.

In endoscopic sinus surgery, the anterior ethmoidal artery (AEA) is usually identified as it traverses obliquely across the fovea ethmoidalis, posterior to the bulla ethmoidalis and anterior to or within the ground lamella's attachment to the skull base. Injury to the AEA may result in hemorrhage, retraction of the AEA into the orbit, and a retrobulbar hematoma. The resulting increase in intraorbital pressure may threaten vision. Waardenburg's syndrome (WS) is a rare congenital, autosomal dominantly inherited disorder, distinguished by characteristic facial features, pigmentation abnormalities, and profound, congenital, sensorineural hearing loss. We present a case of AEAs located anterior to the bulla ethmoidalis in a 36-year-old male with WS and chronic rhinosinusitis. The anatomic abnormality was not obvious on a preoperative computed tomography scan and was discovered intraoperatively when the left AEA was injured, resulting in a retrobulbar hematoma. The hematoma was immediately identified and decompressed endoscopically without lasting complications. The AEA on the right was identified intraoperatively and preserved. The characteristic craniofacial features in WS were probably associated with the abnormal vascular anatomy. Endoscopic sinus surgeons should be aware of these potential anatomic anomalies in patients with abnormal craniofacial development.