Anatomoclinical features of trigeminal neuralgia caused by vertebrobasilar dolichoectasia

Vertebrobasilardolichoectasia (VBDE) is a rare cause of trigeminal neuralgia (TN). The size and tortuous course of the offending vessel poses a particular challenge when attempting a surgical treatment with microvascular decompression. There are few reports on the radiological and surgical anatomy encountered in this condition. The anatomical and radiological features of a surgical series of 7 patients with TN caused by VBDE and treated with microvascular decompression (MVD) are presented. Morphometric measurements and three-dimensional reconstructions obtained from preoperative magnetic resonance imaging were compared with microsurgical findings. Trigeminal nerve compression was found on the left side in six cases (86%). The neurovascular compression was caused by the basilar artery (BA) in 4 cases and the vertebral artery (VA) in three cases, with two cases showing a multiple compression involving other vessels. The BA showed a mean maximal diameter of 6,5 mm (5-9,1 mm), a mean lateral deviation of 19,3 mm (14,422,1 mm) and a mean elevation of the basilar tip above the dorsum sellae of 10,5 mm (4,4-14,8 mm). MVD was successfully performed in all patients yielding a permanent pain relief in six of the patients. Preoperative assessment of the neurovascular relations within the cerebellopontine angle is paramount for the surgical planning in patients with TN caused by VBDE.