Microvascular Decompression for Trigeminal Neuralgia Caused by Vascular Compression on the Trigeminal Sensory Nucleus and Descending Trigeminal Tract.

ABSTRACT

BACKGROUND: Trigeminal neuralgia (TN) is characterized by paroxysmal episodes of severe shocklike orofacial pain typically resulting from arterial compression on the trigeminal root entry zone. However, neurovascular conflict in more proximal parts of the trigeminal pathway within the pons is extremely rare. METHODS: The authors present a case of microvascular decompression for TN caused by dual arterial compression on the dorsolateral pons, along with a brief literature review. RESULTS: Our patient was a 74-year-old man with episodic left-sided facial stabbing pain. Brain magnetic resonance imaging revealed a dual arterial compression on dorsolateral pons, the known site of the trigeminal sensory nucleus and descending trigeminal tract. Microvascular decompression was performed via a retrosigmoid approach. Complete pain relief and partial improvement of the facial hypesthesia were achieved immediately after surgery and the Barrow Neurological Institute (BNI) pain intensity score improved from V to I, and the BNI hypesthesia score decreased from III to II within a month following surgery. The literature review identified 1 case of TN secondary to an arteriovenous malformation in root entry zone with lateral pontine extension. One month following partial coagulation of the draining vein, the patient was reportedly able to reduce medication dosage by half to achieve an improvement of BNI pain intensity score from V to IIIa. CONCLUSIONS: Neurovascular compression in the trigeminal tract and nucleus is a rare but potential cause of TN. A thorough investigation of the trigeminal pathway should be considered during preoperative evaluation and intraoperative inspection, particularly if no clear offending vessel is identified.