Somatosensory and auditory brainstem evoked potentials during choroid plexus angioma removal.

Intraoperative combined SEP and BAEP monitoring provides a high level of safety for patients undergoing high risk intracranial surgical procedures. We performed this type of monitoring in a rare case of choroid plexus angioma, embedded into the pulvinar of the right thalamus, which was resected via a transcallosal approach. The SEP pattern deteriorated during parietal brain retraction and thalamic dissection, but never completely disappeared. The BAEP pattern remained unchanged during the entire operation. The patient suffered incomplete hemiparesis postoperatively, but recovered completely within 10 days. After this time the SEP pattern returned to normal. This case points out that pathological change of intraoperative SEP pattern without loss of components suggests an incomplete hemiparesis. There is, however, a good chance of full recovery in the early postoperative period.