The authors report a case of intracranial epidural hemorrhage (ICEH) during spinal surgery. We could not find ICEH, though we recorded transcranial electrical stimulation motor evoked potentials (TcMEPs). A 35-year-old man was referred for left anterior thigh pain and low back pain that hindered sleep. Sagittal T2-weighted magnetic resonance imaging revealed an intradural tumor at L3-L4 vertebral level. We performed osteoplastic laminectomy and en bloc tumor resection. TcMEPs were intraoperatively recorded at the bilateral abductor digiti minimi (ADM), quadriceps, tibialis anterior and abductor hallucis. When we closed a surgical incision, we were able to record normal TcMEPs in all muscles. The patient did not fully wake up from the anesthesia. He had right-sided unilateral positive ankle clonus 15 min after surgery in spite of bilateral negative of ankle clonus preoperatively. Emergent brain computed tomography scans revealed left epidural hemorrhage. The hematoma was evacuated immediately via a partial craniotomy. There was no restriction of the patient's daily activities 22 months postoperatively. We should pay attention to clinical signs such as headache and neurological findgings such as DTR and ankle clonus for patients with durotomy and cerebrospinal fluid (CSF) leakage. Spine surgeons should know that it was difficult to detect ICEH by monitoring with TcMEPs. The incidence of intracranial hemorrhage (ICH) after spinal surgery is rare, whereas that of intracranial epidural hemorrhage (ICEH) is extremely rare.
Spinal Cord Series and Cases1,2 There are only five reported cases of ICEH after spinal surgery.2-3 Kaloostain et al. reported a 14% mortality rate in patients who had ICH after spinal surgery.4 Therefore, it is important to detect ICH after spinal surgery as quickly as possible. To the best of our knowledge, there have been no reports in the English literature evaluating intraoperative cauda eqina monitoring in patients who develop ICH after spinal surgery. In the present study, we describe early detection of ICEH after spinal surgery.A 35-year-old man was referred for neurological evaluation with a 6-month complaint of low back pain that hindered sleep and left anterior thigh pain. No remarkable medical history was noted. His neurological examination was normal with no motor or sensory deficits. We suspected an intradural schwannoma at the L3-L4 vertebral level with magnetic resonance imaging.We performed osteoplastic laminectomy and tumor resection. After releasing cerebrospinal fluid (CSF) for local decompression, we identified the tumor within the arachnoid layer and removed it en bloc. The operation was completed uneventfully and we repaired the dura. The tumor was histopathologically identified as a schwannoma. The total operation time was 4 h and 6 min, intraoperative CSF loss was unknown, and blood loss was o200 ml. We performed cauda equina monitoring intraoperatively.An electrophysiological monitoring system was used to record the transcranial electorical stimulation motor evoked potentia...