Hisaharu Goto

Intra-operative monitoring of lower extremity motor-evoked potentials by direct cortical stimulation.

OBJECTIVE Motor-evoked potentials (MEPs) are commonly recorded from upper-extremity muscles, whereas lower-extremity MEP (LE-MEP) monitoring has not been adequately established. The goal of the study was to develop a MEP monitoring method using direct cortical stimulation (DCS) for predicting motor deficits of lower extremities. METHODS Intra-operative LE-MEP monitoring was performed in 22 patients. After craniotomy, a subdural electrode was placed on the cortex so that the optimal contact was positioned 2 cm lateral from the midline on the motor cortex. The electrodes for stimulation consisted of a cathode at Fpz and an anode at the optimal contact site on the motor cortex. After stimulation was performed with short trains of five stimuli, LE-MEPs were recorded from the lower-limb muscles. RESULTS LE-MEPs were consistently recorded in all patients. Disappearance or amplitude reduction of MEP waveforms was observed in five patients, but the MEP waveforms had recovered and remained at the control level by dural closure, and no permanent motor deficit was observed in any patient. CONCLUSIONS We accomplished LE-MEP recording during supratentorial surgery using monopolar DCS with a subdural electrode placed on the convex side of the motor cortex. SIGNIFICANCE A useful method of intra-operative LE-MEP recording was described.

Importance of Early Postoperative Body Temperature Management for Treatment of Subarachnoid Hemorrhage.

BACKGROUND The importance of acute-phase brain temperature management is widely accepted for prevention of exacerbation of brain damage by a high body temperature. METHODS In this study, we investigated the influence of body temperature in the early postoperative period on the outcomes of 62 patients with subarachnoid hemorrhage who were admitted to our department. Body temperature was measured from day 4 to day 14 after onset. The patients were divided into those treated with surgical clipping (clip group) and coil embolization (coil group), those graded I-III (mild) and IV-V (severe) based on the Hunt & Hess classification on admission, those with and without development of delayed cerebral ischemia (DCI), and those with favorable and poor outcomes. Body temperatures throughout the hospital stay were compared in each group. RESULTS There was no significant difference in body temperature between the clip and coil groups or between the mild and severe groups, but body temperature was significantly higher in patients with DCI compared to those without DCI, and in patients with a poor outcome compared to those with a favorable outcome. CONCLUSIONS Fever in the early postoperative period of subarachnoid hemorrhage is associated with development of DCI and a poor outcome.

Adverse Events after Unruptured Cerebral Aneurysm Treatment: A Single-center Experience with Clipping/Coil Embolization Combined Units

BACKGROUND Indications of clipping (Clip) or coil embolization (Coil) for unruptured cerebral aneurysms (uAN) was not elaborated because prediction of rupture and risk of treatment are difficult. This study aims to determine the risk-benefit analysis of treating uAN by a comprehensive and retrospective investigation of the adverse events and sequelae in patients treated by our Clip/Coil combined units. METHODS Clip and Coil were performed in 141 and 80 patients, respectively; Clip for middle cerebral artery AN and Coil for paraclinoid or basilar apex AN. Worsening of modified Rankin scale or mini-mental state examination was defined as major morbidity. Minor morbidity or transient morbidity was defined as other neurologic deficits. Mortality and these morbidities were considered as serious adverse events. Convulsion or events outside the brain were defined as mild adverse events. RESULTS Total mortality and major morbidity were low. Incidence of serious adverse events was not significantly different between the Clip and Coil (17 patients [12.1%] and 6 patients [7.5%]), but the number of total adverse events was significantly different (32 patients [22.7%] in Clip vs. 8 patients [10.0%] in Coil). Because mild morbidities were significantly more frequent in the Clip (20 patients [14.2%]) compared with the Coil (2 patients [2.5%]). Convulsion occurred in 11 (7.8%) patients in the Clip but none in the Coil. CONCLUSIONS Our combined unit decreased the occurrence of mortality/major morbidity; however, minor adverse effects were common, especially in the Clip group because of many intrinsic problems of Clip itself. This result suggests further consideration for the treatment modality for uAN.

Real-time ultrasound-guided endoscopic surgery for putaminal hemorrhage.

OBJECT Endoscopic surgery plays a significant role in the treatment of intracerebral hemorrhage. However, the residual hematoma cannot be measured intraoperatively from the endoscopic view, and it is difficult to determine the precise location of the endoscope within the hematoma cavity. The authors attempted to develop real-time ultrasound-guided endoscopic surgery using a bur-hole-type probe. METHODS From November 2012 to March 2014, patients with hypertensive putaminal hemorrhage who underwent endoscopic hematoma removal were enrolled in this study. Real-time ultrasound guidance was performed with a bur-hole-type probe that was advanced via a second bur hole, which was placed in the temporal region. Ultrasound was used to guide insertion of the endoscope sheath as well as to provide information regarding the location of the hematoma during surgical evacuation. Finally, the cavity was irrigated with artificial cerebrospinal fluid and was observed as a low-echoic space, which facilitated detection of residual hematoma. RESULTS Ten patients with putaminal hemorrhage>30 cm3 were included in this study. Their mean age (±SD) was 60.9±8.6 years, and the mean preoperative hematoma volume was 65.2±37.1 cm3. The mean percentage of hematoma that was evacuated was 96%±3%. None of the patients exhibited rebleeding after surgery. CONCLUSIONS This navigation method was effective in demonstrating both the real-time location of the endoscope and real-time viewing of the residual hematoma. Use of ultrasound guidance minimized the occurrence of brain injury due to hematoma evacuation.

Postoperative Dural Arteriovenous Fistula in a Patient with Cowden Disease: A Case Report

We report the case of a 37-year-old male with Cowden disease that caused a gradual neurological deficit because of rupture of a brain stem cavernous hemangioma. Removal of the hemangioma and hematoma was performed with an infrafacial triangle approach. Nine months after the operation, magnetic resonance imaging showed abnormal vessels on the cerebellar surface. Digital subtraction angiography showed a dural arteriovenous fistula (dAVF) from part of the meningeal artery to the ectatic inferior vermian vein with cortical reflux. After embolization, surgical obliteration of the dAVF was performed. Surgical findings showed neovascularization in the thickened dura, in which dural vessels shunted to cerebellar vessels through adhesion between the dura mater and cerebellar surface. Therefore, the thickened dura was removed with the cerebellar surface. This case suggests that postoperative angiogenesis may cause arteriovenous fistula in patients with Cowden disease.

Factors influencing spinal canal stenosis in patients with long-term controlled hydrocephalus treated with cerebrospinal fluid shunt

PurposeSpinal canal stenosis (CS) occurs in patients with hydrocephalus who are treated with cerebrospinal fluid (CSF) shunting. The pathophysiology of CS comprises CSF overdrainage. We analyzed the incidence of CS and the factors causing it.MethodsThirty-three patients who underwent ventriculoperitoneal shunt during childhood visited the Outpatient Department in Yamaguchi University Hospital in 2006. Diameters of spinal canal at C4 were measured. Treatment procedure, age, and type of hydrocephalus in the patients with CS were compared with those without CS.ResultsOf the 33 patients, 10 (30.3%) presented CS, and two (6.1%) were symptomatic. A low-pressure valve caused CS with a significantly higher incidence than a medium- or high-pressure valve (60.0% vs. 17.4%, P < 0.05). Although the difference was not significant, the average age of shunt insertion for a patient with CS was slightly less (0.87 ± 0.99) than for a patient without CS (1.63 ± 1.58). No differences in the CS incidence were observed between obstructive and communicating hydrocephalus.ConclusionIn order to prevent CS, the hydrocephalus should be appropriately controlled by using a medium- or high-pressure valve until the diameter of the spinal canal reaches the required level. Adjustment of the programmable valve with the patient’s growth should be ideal.

Repeated Cerebral Ischemia Caused by Extracranial Carotid Artery Dolichoectasia

We report the case of a 67‐year‐old man with repeating cerebral embolism caused by a dolichoectatic right common carotid artery. The patient had a history of hypertension, hypercholesterolemia, cigarette smoking, and a postoperative abdominal aortic aneurysm. He presented with a sudden onset of weakness of the left arm and leg. Magnetic resonance imaging revealed old and fresh infarction in the right cerebral hemisphere. Carotid duplex ultrasonography showed a dolichoectatic right common carotid artery with a maximum diameter of 39 mm with thick plaque and strong spontaneous echo contrast. The flow velocity was considerably reduced, which caused thrombus formation, and strong antithrombotic therapy was required. This case provides a rare example of ischemic stroke caused by extracranial carotid artery dolichoectasia.

Intracranial epidural hemorrhage during lumbar spinal surgery

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.

P31-9 Intraoperative monitoring of the motor evoked potential elicited by direct cortical stimulation of the lower extremities

distance. CST course shift on intraop MRI comparing pres MRI was shown in 6 cases (31.5%), that means 19 stimulation points (32.7%). Radical resection was performed in 14 (87.5%), subtotal in 2 patients (12.5%). After surgery developed 2 temporary hemiparesis and 1 speech disorders that resolved in 3 days and 3 months respectively. Permanent left side hemianopsia developed in one patient. Conclusion: Subcortical CST mapping is superior to extraoperative CST imaging on MRI DTI. Intraoperative MRI improves reliability of CST dermination.

P31-10 Intraoperative monitoring of the lower extremity motor evoked potential (LE-MEP) elicited by direct cortical stimulation

distance. CST course shift on intraop MRI comparing pres MRI was shown in 6 cases (31.5%), that means 19 stimulation points (32.7%). Radical resection was performed in 14 (87.5%), subtotal in 2 patients (12.5%). After surgery developed 2 temporary hemiparesis and 1 speech disorders that resolved in 3 days and 3 months respectively. Permanent left side hemianopsia developed in one patient. Conclusion: Subcortical CST mapping is superior to extraoperative CST imaging on MRI DTI. Intraoperative MRI improves reliability of CST dermination.