Introduction : To prevent spinal lesions during surgery we can use somatosensory evoked potentials (SSEP) to monitor the patients who are under surgery particularly the ones under the spinal cord surgery.

Case Report: The following case refers to the monitoring of a 23 year – old youth with the use of Intraoperative SSEP who has been under the operation of tumor removal with the diagnosis of space occupying mass in the conous region of spine in Tabriz Shohada Hospital.

Conclusion: SSEP study for left tibial nerve after surgery was the same as before surgery. Pathology diagnosis was epandymom. Patient gave recovery process in few days.