January 16, 2015
Most often with careful selection of patients an intraoperative vascular conflict is found during MVD for hemifacial spasm. However, there are extremely rare situations that despite correct diagnosis no offending vessel can be found intraoperatively. And then the decision has to made, what is the next step to provide the patient with some relief while the patient is undergoing this surgery. This is a case of one of my patients who was found to have no significant vascular offending vessel intraoperatively. The MRI was actually negative in this case preoperatively. However, I do offer an exploratory posterior fossa operation to patients who have typical hemifacial spasm even though no clear offending vessel can be found in MRI as most of the time I do find a convincing offending vessel at the root exit zone of the nerve despite unremarkable preoperative imaging findings. So this patient underwent a right-sided retromastoid craniotomy. You can see the eighth cranial nerve, you can see the labyrinthine artery that is following the facial nerve to the internal auditory meatus. And here's the root exit zone of the nerve and I'm massaging the nerve as I'm unable to find any vessel that was compressing the root exit zone of the nerve. I looked very much carefully, even more caudally along the brain stem and no compressive vessel could be found. And I feel in these situations a gentle massage of the root exit zone with a number six dissector can potentially provide some relief of the spasms, even though can be relatively temporary. And these patients usually wake up with not necessarily any significant worsening of their facial weakness related to their Botox injection. So as you can see the gentle massage, I'm using number six at the root exit zone of the nerve. If the patient does not have any preoperative facial weakness, performance of this maneuver should be carefully discussed with the patient due to potential risk of facial weakness postoperatively. Thank you.
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