Delayed Contralateral Trigeminal Neuralgia After Microvascular Decompression and Postoperative Changes in Venous Outflow.

A 66-year-old woman had presented with a 3-month history of left trigeminal neuralgia. She had undergone successful microvascular decompression for right-sided trigeminal neuralgia 8 years previously. To optimize visualization, microvascular decompression for trigeminal neuralgia has been commonly associated with sacrifice of the superior petrosal vein during surgery. The absence of sufficient collaterals can result in most of the posterior fossa venous drainage relying solely on the contralateral superior petrosal vein, leading to subsequent vessel enlargement and a compressive effect on the trigeminal nerve and causing iatrogenic contralateral trigeminal neuralgia. We have provided preoperative and intraoperative images illustrating nicely the adapted postoperative change in venous outflow causing contralateral compression of the trigeminal nerve. Consecutive treatment effects should be carefully considered when offering and performing surgical microvascular decompression.