An Unusual Culprit: Vertebrobasilar Dolichoectasia Presenting as Trigeminal Neuralgia

Abstract

Background: Trigeminal neuralgia (TN) is a debilitating neuropathic pain disorder most commonly caused by neurovascular
compression at the trigeminal nerve root entry zone. While classical cases are typically due to small arterial loops, secondary causes
such as vertebrobasilar dolichoectasia (VBD) are rare but clinically significant and often under-recognized.
Case Presentation: We report a 62-year-old male presenting with a 6-month history of recurrent, severe, right-sided, electric shocklike
facial pain involving the maxillary and mandibular divisions of the trigeminal nerve. The pain was triggered by routine activities
such as chewing and speaking, consistent with classical trigeminal neuralgia. Neurological examination revealed mild hyperesthesia
over the affected dermatomes without motor deficit.
Magnetic resonance imaging with angiography demonstrated an abnormal vertebrobasilar configuration with significant rightward
lateral displacement and high bifurcation of the basilar artery. Although the arterial diameter did not meet conventional criteria for
ectasia, the vessel was seen abutting and indenting the cisternal segment of the right trigeminal nerve, confirming neurovascular
compression. These findings were consistent with vertebrobasilar dolichoectasia based on Smoker’s criteria.
The patient was treated with carbamazepine, resulting in significant symptomatic improvement, and remains under follow-up for
potential surgical intervention if symptoms become refractory.
Discussion: This case highlights an important diagnostic and pathophysiological consideration: vascular geometry and displacement
may be more critical than arterial diameter in producing symptomatic neurovascular conflict. Unlike classical TN, VBD-associated
TN involves a large, tortuous vessel capable of exerting sustained mechanical distortion on the trigeminal nerve. Recognition of such
structural causes is essential, as they carry distinct prognostic and therapeutic implications.
Conclusion: Vertebrobasilar dolichoectasia is an uncommon but important cause of secondary trigeminal neuralgia. Detailed
neurovascular imaging is crucial for diagnosis, as identification of vascular morphology—not merely vessel caliber—can influence
clinical decision-making and long-term management.