Multi-channel motor evoked potential monitoring during anterior cervical discectomy and fusion.

OBJECTIVES: Anterior cervical discectomy and fusion (ACDF) surgery is the most common surgical procedure for the cervical spine with low complication rate. Despite the potential prognostic benefit, intraoperative neurophysiological monitoring (IONM), a method for detecting impending neurological compromise, is not routinely used in ACDF surgery. The present study aimed to identify the potential benefits of monitoring multi-channel motor evoked potentials (MEPs) during ACDF surgery. METHODS: We retrospectively reviewed 200 consecutive patients who received IONM with multi-channel MEPs and somatosensory evoked potentials (SSEPs). On average, 9.2 muscles per patient were evaluated under MEP monitoring. RESULTS: The rate of MEP change during surgery in the multi-level ACDF group was significantly higher than the single-level group. Two patients from the single-level ACDF group (1.7%) and four patients from the multi-level ACDF group (4.9%) experienced post-operative motor deficits. Multi-channel MEPs monitoring during single and multi-level ACDF surgery demonstrated higher sensitivity, specificity, positive predictive and negative predictive value than SSEP monitoring. CONCLUSIONS: Multi-channel MEP monitoring might be beneficial for the detection of segmental injury as well as long tract injury during single- and multi-level ACDF surgery. SIGNIFICANCE: This is first large scale study to identify the usefulness of multi-channel MEPs in monitoring ACDF surgery.

Corticobulbar motor evoked potentials from tongue muscles used as a control in cervical spinal surgery.

OBJECTIVE: Motor evoked potentials (MEPs) changes might be caused to the non-surgically induced factors during cervical spinal surgery. Therefore, control MEPs recorded cranially to the exit of the C5 root are highly recommendable in cervical spinal surgery. We studied whether corticobulbar MEPs (C-MEPs) from tongue muscle could be used as a control MEPs in cervical spinal surgery. METHODS: Twenty-five consecutive cervical spinal surgeries were analyzed. Stimulation of motor area for tongue was done by subcutaneous electrodes placed at C3/C4 (10-20 EEG System), and recording was done from both sides of tongue. RESULTS: C-MEPs were recorded successfully 24 out of the 25 (96%) tested patients. Forty-six out of fifty MEPs (92%) from tongue muscles were monitorable from the baseline. In two patients, we could obtain only unilateral C-MEPs. Mean MEPs latencies obtained from the left and right side of the tongue were 11.5 ± 1 ms and 11.5 ± 0.8 ms, respectively. CONCLUSIONS: Monitoring C-MEPs from tongue muscles might be useful control in cervical spinal surgery. They were easily elicited and relatively free from phenomenon of peripheral stimulation of the hypoglossal nerves. SIGNIFICANCE: This is first study to identify the usefulness of C-MEPs as a control of cervical spinal surgery.

Gender effect on neuromyelitis optica spectrum disorder with aquaporin4-immunoglobulin G.

BACKGROUND: Neuromyelitis optica spectrum disorder with aquaporin4-immunoglobulin G (NMOSD-AQP4) is an inflammatory disease characterised by a high female predominance. However, the effect of gender in patients with NMOSD-AQP4 has not been fully evaluated. OBJECTIVE: The aim of this study was to determine the effect of gender in clinical manifestations and prognosis of patients with NMOSD-AQP4. METHODS: The demographics, clinical and radiological characteristics, pattern reversal visual evoked potential (VEP) test results, and prognosis of 102 patients (18 males) with NMOSD-AQP4 were assessed. RESULTS: Male patients had a higher age at onset (48.7 vs 41 years, p = 0.037) and less optic neuritis as the onset attack (17% vs 44%, p = 0.026), higher tendency to manifest as isolated myelitis over the follow-up period (67% vs 28%, p = 0.005), fewer optic neuritis attacks per year (0.08 vs 0.27, p < 0.001), and shorter relative P100 latency on VEP testing (97.1% vs 108.3%, p = 0.001). Moreover, male gender was significantly associated with the absence of optic neuritis attacks over the follow-up period independent of their age of onset. CONCLUSION: In NMOSD-AQP4 patients, gender impacts on disease onset age and site of attack. This may be an important clue in identifying NMOSD-AQP4 patients with limited manifestations as well as in predicting their clinical courses.

The incidence of and risk factors for ischemic complications after microsurgical clipping of unruptured middle cerebral artery aneurysms and the efficacy of intraoperative monitoring of somatosensory evoked potentials: A retrospective study.

OBJECTIVES: Ischemic complications (ICs) account for 6.7% after microsurgical clipping of unruptured intracranial aneurysms. This study aimed to evaluate the efficacy of somatosensory evoked potential (SSEP) monitoring during microsurgical clipping of unruptured middle cerebral artery (MCA) aneurysms and evaluate the incidence of and risk factors for ischemic complications after clipping of unruptured MCA aneurysms. PATIENTS AND METHODS: Herein, 1208 patients with cerebral aneurysms and treated with microsurgical clipping between May 2003 and February 2015 were enrolled. Those with multiple aneurysms, history of head trauma, subarachnoid hemorrhage, bypass and/or endovascular treatment, and intraoperative rupture were excluded. Subsequently, 411 patients with single unruptured MCA aneurysms treated with simple microsurgical clipping were enrolled. Patients were divided into two groups based on the application of SSEP monitoring during surgery. RESULTS: The IC rate was 0.9% and 5.6% in the SSEP and non-SSEP groups, respectively. Univariate analysis revealed that age≥62.5years, aneurysm size≥4.15mm, temporary clipping, history of hyperlipidemia and stroke, and no-SSEP monitoring were risk factors for ICs. Multivariate logistic regression analysis showed that age≥62.5years (odds ratio [OR]=7.7; 95% confidence interval [95% CI]=1.5-37.7; P=0.011), previous stroke (OR=26.8, 95% CI=2.4-289.2, P=0.007), and inversely SSEP monitoring (OR=0.14, 95% CI 0.02-0.72, P=0.019) were independent risk factors for ICs. CONCLUSION: Clinicians should consider the possibility of IC during microsurgical clipping of unruptured MCA aneurysms in patient≥62.5years and/or a history of stroke. Intraoperative SSEP monitoring is an effective and feasible tool for preventing IC.