Microvascular decompression through an anterior transpetrosal approach for trigeminal neuralgia caused by persistent...

Trigeminal neuralgia (TN) is most commonly caused by neurovascular compression, and microvascular decompression (MVD) remains the standard surgical treatment for patients refractory to medical therapy. Rarely, TN is associated with persistent primitive trigeminal artery (PPTA) or its PPTA variant (PPTAv). TN caused by PPTAv traversing Meckel's cave is extremely rare.

A 68-year-old female presented with TN affecting the left V2 and V3 distributions. Despite pharmacological management, her pain progressively worsened; therefore, MVD was performed. Preoperative magnetic resonance angiography and fast imaging employing steady-state acquisition revealed a PPTAv arising from the left internal carotid artery, coursing tortuously through Meckel's cave before entering the posterior fossa. Neurovascular compression of the trigeminal nerve (cranial nerve V [CN V]) within Meckel's cave by this vessel was identified as the cause of TN. To achieve adequate opening of Meckel's cave, the anterior transpetrosal approach (ATPA) was selected. Intraoperatively, a markedly tortuous PPTAv was identified within Meckel's cave. Opening Meckel's cave enabled successful transposition of the PPTAv and decompression of CN V. Postoperatively, the neuralgia resolved completely, with no complications such as hearing impairment or cerebrospinal fluid leakage. At 6 months after surgery, the patient remained pain-free without recurrence and required no medication or additional treatment.

We report a rare case of TN caused by a PPTAv passing through Meckel's cave. Careful evaluation of preoperative imaging is critical in TN cases with atypical vascular anatomy. In this case, ATPA facilitated the safe opening of Meckel's cave and the effective transposition of the offending vessel, suggesting that it may be a useful surgical option in carefully selected cases.