Transient magnetic resonance imaging signal alterations in the brainstem after microvascular decompression for trigeminal neuralgia: case report.

OBJECTIVE AND

IMPORTANCE

We present a case of transient signal alterations along the brainstem path of the trigeminal nerve after microvascular decompression in a patient with trigeminal neuralgia. Such signal changes have been previously reported to represent infarction, but in our patient, they seemed to represent reactive neural and nuclear changes attributable to operative manipulation.

CLINICAL PRESENTATION: A 43-year-old woman presented with gradually increasing, medically refractory recurrent trigeminal neuralgia 16 months after initial successful microvascular decompression for trigeminal neuralgia. Repeat microvascular decompression resulted initially in complete pain relief; however, her pain suddenly returned on the 3rd postoperative day. Magnetic resonance imaging (MRI) of this recurrent pain revealed new signal alterations along the brainstem path of the trigeminal nerve. Other than marked reduction in her trigeminal neuralgia, the patient had no postoperative alterations of trigeminal sensory or motor function.

INTERVENTION: The patient's residual postoperative trigeminal neuralgia was successfully treated with carbamazepine. Because of the absence of worrisome signs and symptoms corresponding to the MRI signal alterations, no additional therapy was elected. Follow-up MRI in 1 month revealed near-complete resolution of the postoperative signal alterations along the brainstem path of the trigeminal nerve.

CONCLUSION

MRI signal alterations along the brainstem path of the trigeminal nerve after microvascular decompression may be only reactive and do not always represent infarction. Depending on the clinical picture, observation may be all that is necessary in such cases.