brought to you by the nerve stimulation experts at Neurosign

June 13, 2021

Petroclival meningioma



A young female in her 30’s with a 6cm petroclival meningioma. It is in the cerebellopontine angle, extending anteriorly to the clivus,  just entering the internal auditory canal. It appears to be pushing the facial nerve so that it lies on the anterior surface of the tumour, and extending down to the lower cranial nerves. There is no obvious compression of the lower nerves, but she has developed difficulty in swallowing. However, there is severe brainstem compression and it may be that her swallowing difficulties are more central rather than the cranial nerve.

From a monitoring perspective, this is in the same location as an acoustic schwannoma,  so my cranial nerve monitoring is the same as usual – 4 channels for facial nerve, trigeminal, glossopharyngeal, vagus and accessory. In addition, I am using tibial SSEPS to  onitor brainstem function.

With the patient on the operating table, all waveforms are flat and I have a good SEP on the left side, and poor or none on the right. This agrees with her preoperative clinical assessment of right sided severe ataxia.