Dementia, Subtype of Seizures, and the Risk of New Onset Seizures: A Cohort Study.

BACKGROUND: Seizure disorders have been identified in patients suffering from different types of dementia. However, the risks associated with the seizure subtypes have not been characterized. OBJECTIVE: To compare the occurrence and risk of various seizure subtypes (focal and generalized) between patients with and without a dementia diagnosis. METHODS: Data from 40.7 million private insured patient individual electronic health records from the U.S., were utilized. Patients 60 years of age or more from the Optum Insight Clinformatics-data Mart database were included in this study. Using ICD-9 diagnoses, the occurrence of generalized or focal seizure disorders was identified. The risk of new-onset seizures and the types of seizures associated with a dementia diagnosis were estimated in a cohort of 2,885,336 patients followed from 2005 to 2014. Group differences were analyzed using continuity-adjusted chi-square and hazard ratios with 95%confidence intervals calculated after a logistic regression analysisResults:A total of 79,561 patient records had a dementia diagnosis, and 56.38%of them were females. Patients with dementia when compared to those without dementia had higher risk for seizure disorders [Hazard ratio (HR) = 6.5 95%CI = 4.4-9.5]; grand mal status (HR = 6.5, 95%CI = 5.7-7.3); focal seizures (HR = 6.0, 95%CI = 5.5-6.6); motor simple focal status (HR = 5.6, 95%CI = 3.5-9.0); epilepsy (HR = 5.0, 95%CI = 4.8-5.2); generalized convulsive epilepsy (HR = 4.8, 95%CI = 4.5-5.0); localization-related epilepsy (HR = 4.5, 95%CI = 4.1-4.9); focal status (HR = 4.2, 95%CI = 2.9-6.1); and fits convulsions (HR = 3.5, 95%CI = 3.4-3.6). CONCLUSION: The study confirms that patients with dementia have higher risks of generalized or focal seizure than patients without dementia.

Motor unit number estimation of facial muscles using the M Scan-Fit method.

INTRODUCTION: M Scan-Fit, an automated method for motor unit number estimation (MUNE), was assessed in muscles innervated by the facial nerve. METHODS: Healthy volunteers were recruited. M Scans were recorded twice from nasalis and depressor anguli oris (DAO) muscles, and then fitted to a probabilistic model. RESULTS: Twenty-one subjects were evaluated; 38% were females and 62% were males, with a mean age of 34.71 years. The average number of MUs was 38.57 on both testing occasions (t ≤ 0.0001; P = 1.0) for the nasalis. For the DAO, results were 20.62 MUs for the first and 23.48 for the second (t = -2.12; P = .04). Pearson's interrater correlation coefficients were 0.96 (P < .0001) for nasalis and 0.87 (P ≤ .01) for DAO. Intraclass correlation coefficients were 0.88 (P ≤ .01) for nasalis and 0.39 (P = .37) for DAO. DISCUSSION: M Scan-Fit MUNE is an automated, accurate, reliable method of estimating MU number and size from facial muscles.

Reference values of upper extremity nerve conduction studies in a Colombian population.

OBJECTIVE: To establish appropriate reference values of upper extremity nerve conduction studies (NCS) at the Del Valle University Hospital, from Colombia. METHODS: Two hundred and twenty-two (N = 222) healthy volunteers were recruited. Latencies, amplitudes and conduction velocities from the Median, Ulnar, and Radial nerves were performed following recommendations from Buschbacher and Prahlow. Then, according to the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) task force for reference value establishment, analyses of variance were run where each electrophysiological parameter from every nerve tested was used as dependent variable, to define which characteristics have to be kept for the model. Percentiles 3 and 97 from each of the parameters were derived. Finally, a multivariate quantile regression analysis model was tested. RESULTS: Sensory percentiles were 2.8-3.5 ms, 18.9-120.8 µV, and 40.0-50.0 m/s for the Median, 2.1-2.9 ms, 10.4-106.9 µV, and 41.0-58.0 m/s for the Ulnar, while 2.6-3.5 ms, 11.3-69.9 µV, and 39.0-54.0 m/s for the Radial nerve. The same parameters for motor function were 2.8-3.9 ms, 4.6-15.0 mV, and 49.0-68.0 m/s for the Median, while 2.3-3.5 ms, 3.9-11.5 mV and 51.0-70 m/s for the Ulnar nerve. CONCLUSIONS: Values of latency, amplitude, and conduction velocity of sensory and motor functions from upper extremity nerves among Colombians are similar to equal parameters, obtained by comparable studies of populations alike. SIGNIFICANCE: This is the first study to establish reference values for upper extremity NCS carried out following the AANEM recommendations in a South American population.

Purulent infectious myositis (formerly tropical pyomyositis).

Purulent infectious myositis (PIM), formerly known as tropical pyomyositis, is a pyogenic infection of skeletal muscles. Staphylococcus aureus, a normal human skin inhabitant, is the main pathogen involved, but multiple other microorganisms have been implicated. Although usually a progressive febrile disease with pain in the affected muscle(s), severe, life-threatening forms have been described, especially in immunosuppressed patients and children. PIM may elude early diagnosis given the lack of overlying skin changes. Hence, high index of suspicion followed by imaging modalities (ultrasonography when superficial and computed tomography or magnetic resonance imaging with contrast when deep) help confirm the diagnosis. Treatment requires combination of percutaneous or open surgical drainage along with antimicrobial therapy guided by culture results. The rising incidence of cases due to methicillin-resistant Staphylococcus aureus (MRSA) strains, makes the inclusion of vancomycin be recommended. This paper reviews PIM highlighting its global distribution, causative agents, predisposing factors, management, and potential complications.

Diagnostic accuracy of somatosensory evoked potentials during intracranial aneurysm clipping for perioperative stroke.

Somatosensory evoked potentials (SSEPs) are utilized during aneurysm clipping to detect intraoperative ischemia. We assess the diagnostic accuracy of SSEPs in predicting perioperative stroke during aneurysm clipping. A retrospective review was conducted of 429 consecutive patients who underwent surgical clipping for ruptured and unruptured cerebral aneurysms with intraoperative SSEP monitoring from 2006 to 2013. The relationship between perioperative stroke and SSEP changes was analyzed by calculating the sensitivity, specificity, and area under a Receiving Operating Characteristic curve. Sensitivity and specificity were 42% and 90%, respectively. Area under the curve was 0.66 (95% confidence interval, 0.53-0.79). Reclassification of reversible temporary clip changes to correct for paradoxical classification of SSEP false positives raised the sensitivity from 42 to 65% (p = 0.041, Chi squared test). EEG (electroencephalography) changes increased the specificity (98% vs. 90%, p < 0.001, McNemar's test), but not sensitivity (48% vs. 42%, p = 0.621, McNemar's test) of SSEPs for perioperative stroke. A stepwise logistic regression model selected SSEP amplitude loss (p = 0.006, OR = 3.7 [95% CI 1.5-9.2]) and the SSEP change duration (p = 0.034, OR = 1.8 [95% CI 1.1-3.1]) as independent predictors of perioperative stroke. SSEP changes induced by temporary clipping were highly reversible compared to other SSEP changes (94% vs. 60%, p = 0.003, Fisher exact test), and typically responded to clip removal or readjustment. SSEP changes have high specificity and modest sensitivity for perioperative stroke. Stroke risk is a function of both the magnitude of SSEP amplitude loss and the duration of its loss. Given the modest sensitivity, patients may benefit from multimodal monitoring including motor-evoked potentials during cerebral aneurysm surgery.

Evoked potentials improve multimodal prognostication after cardiac arrest.

AIM: Predicting recovery in comatose post-cardiac arrest patients requires multiple modalities of prognostic assessment. In isolation, absent N20 cortical responses in somatosensory evoked potentials (SSEPs) are a specific predictor of poor outcome. It is unknown whether SSEP results, when assessed in the context of prior knowledge (demographic and clinical information), change the pretest predicted probability of recovery. METHODS: In a single center retrospective study, a cohort of 323 patients admitted to post-cardiac arrest service at a tertiary care center were classified into a group based on SSEP testing. We built adjusted logistic regression models including clinical examination findings on the day SSEPs were recorded to generate a pre-test outcome probability for awakening, withdrawal of life-sustaining therapy (WLST) and survival to discharge. We then added the upper extremity N20 cortical response results to the model to obtain updated outcome probabilities. ROC curve was used to determine the additive effect of using SSEPs to the model. Survival to discharge, awakening, and WLST due to neurological reasons were designated as primary, secondary and tertiary outcomes, respectively. RESULTS: Analyses showed that evoked potentials are ordered in sicker patients. Adding SSEP to the model increased the proportion of patients with less than 1% and 5% chance of survival, as well as the proportion of patients with over 95% chance of WLST. AUC for survival increased from 0.85 to 0.93 when SSEP was included (p = 0.006). CONCLUSION: Adding the N20 SSEP response results to prior knowledge changed the predicted probability of WLST and survival to discharge in comatose post-arrest patients.

Initial absence of N20 waveforms from median nerve somatosensory evoked potentials in a patient with cardiac arrest and good outcomes.

A 34-year-old male was brought to the hospital with a chest gunshot wound. Pulseless upon arrival, blood pressure was absent for 10 minutes. A thoracotomy resulted in return of spontaneous circulation. On hospital day 5, with brainstem reflexes present, he was unresponsive to call or pain, exhibited generalized hyperreflexia and bilateral Babinskys. Median nerve somatosensory evoked potentials (mSSEPs) and brainstem auditory evoked potentials were obtained. International Federation of Clinical Neurophysiology recommendations for mSSEPs and brainstem auditory evoked potentials were followed. Despite absence of the N20 responses from cortical mSSEPs no withdrawal from care was agreed upon. After awaking on day 7, mSSEPs were repeated and present. The patient survived and was discharged with minor deficits. Bilateral absence of N20 responses from mSSEPs performed beyond 48 hours after resuscitation from cardiac arrest is highly associated with bad neurological outcomes. However, variation due to hypothermia, noisy signals, medications, and brain hypo-perfusion must be taken into account.

Diagnostic Accuracy of Somatosensory Evoked Potential Monitoring in Evaluating Neurological Complications During Endovascular Aneurysm Treatment.

BACKGROUND: Somatosensory evoked potential (SSEP) monitoring is used extensively for early detection and prevention of neurological complications in patients undergoing many different neurosurgical procedures. However, the predictive ability of SSEP monitoring during endovascular treatment of cerebral aneurysms is not well detailed. OBJECTIVE: To evaluate the performance of intraoperative SSEP in the prediction postprocedural neurological deficits (PPNDs) after coil embolization of intracranial aneurysms. METHODS: This population-based cohort study included patients ≥18 years of age undergoing intracranial aneurysm embolization with concurrent SSEP monitoring between January 2006 and August 2012. The ability of SSEP to predict PPNDs was analyzed by multiple regression analyses and assessed by the area under the receiver operating characteristic curve. RESULTS: In a population of 888 patients, SSEP changes occurred in 8.6% (n = 77). Twenty-eight patients (3.1%) suffered PPNDs. A 50% to 99% loss in SSEP waveform was associated with a 20-fold increase in risk of PPND; a total loss of SSEP waveform, regardless of permanence, was associated with a greater than 200-fold risk of PPND. SSEPs displayed very good predictive ability for PPND, with an area under the receiver operating characteristic curve of 0.84 (95% CI 0.76-0.92). CONCLUSION: This study supports the predictive ability of SSEPs for the detection of PPNDs. The magnitude and persistence of SSEP changes is clearly associated with the development of PPNDs. The utility of SSEP monitoring in detecting ischemia may provide an opportunity for neurointerventionalists to respond to changes intraoperatively to mitigate the potential for PPNDs.

Perioperative stroke after cerebral aneurysm clipping: Risk factors and postoperative impact.

Stroke is a devastating complication after intracranial aneurysm clipping. Understanding the risk factors that prognosticate perioperative stroke may help to identify patients that would benefit from neuroprotective therapy. This study assesses patient-specific independent predictors of perioperative stroke in relation to surgical aneurysm clipping. Additionally, this study evaluates the postoperative complications of stroke. We performed a retrospective chart review of 437 patients with ruptured and unruptured intracranial aneurysms, which underwent surgical clipping from 2006 to 2013. Multivariate logistical regression was utilized to assess the effect of age, race, gender, subarachnoid hemorrhage, Hunt and Hess (H/H) grade, aneurysm location, and intraoperative somatosensory evoked potentials (SSEPs) changes on the frequency of perioperative stroke. Thirty-five (8.0%) patients developed a stroke within 24h postoperatively. Patients with significant intraoperative SSEP changes were 7.33 (95% confidence interval [CI]: 3.51-15.31) times more likely to develop perioperative strokes. In patients who presented with H/H grade 5, the odds ratio for developing perioperative stroke was 9.21 (95% CI: 1.28-66.13) respectively. In the absence of aneurysm rupture, patients presenting with new-onset stroke were more likely to suffer postoperative complications, stay in the intensive care unit longer, and be discharged to in-patient rehabilitation compared to patients without new-onset stroke. This study suggests that severity of subarachnoid hemorrhage based on the patient's clinical condition increases the risk of perioperative stroke in patients with surgical aneurysm clipping. SSEP changes and high-grade H/H scores can serve as independent predictors of perioperative stroke, with the latter having the greatest predictive value.

Brainstem Auditory Evoked Potentials' Diagnostic Accuracy for Hearing Loss: Systematic Review and Meta-Analysis.

Background Microvascular decompression (MVD) utilizes brainstem auditory evoked potential (BAEP) intraoperative monitoring to reduce the risk of iatrogenic hearing loss. Studies report varying efficacy and hearing loss rates during MVD with intraoperative monitoring. Objectives This study aims to perform a comprehensive review and study of diagnostic accuracy of BAEPs during MVD to predict hearing loss in studies published from January 1984 to December 2013. Methods The PubMed/MEDLINE and World Science databases were searched. Studies performed MVD for trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia or geniculate neuralgia and monitored intraoperative BAEPs to prevent hearing loss. Retrospectively, BAEP parameters were compared with postoperative hearing. The diagnostic accuracy of significant change in BAEPs, which includes loss of response, was tested using summary receiver operative curve and diagnostic odds ratio (DOR). Results A total of 13 studies were included in the analysis with a total of 2,540 cases. Loss of response pooled sensitivity, specificity, and DOR with 95% confidence interval being 74% (60-84%), 98% (88-100%), and 69.3 (18.2-263%), respectively. The similar significant change results were 88% (77-94%), 63% (40-81%), and 9.1 (3.9-21.6%). Conclusion Patients with hearing loss after MVD are more likely to have shown loss of BAEP responses intraoperatively. Loss of responses has high specificity in evaluating hearing loss. Patients undergoing MVD should have BAEP monitoring to prevent hearing loss.

Diagnostic Accuracy of Somatosensory Evoked Potentials in Evaluating New Neurological Deficits After Posterior Cervical Fusions.

STUDY DESIGN: This study examined the diagnostic accuracy of significant changes of somatosensory evoked potentials (SSEPs) to evaluate and predict postoperative neurological deficits after posterior cervical fusions (PCF). Eight hundred forty six eligible patients underwent PCF at the University of Pittsburgh Medical Center (UPMC), from 2010 to 2012. OBJECTIVE: To assess the specificity and sensitivity of intraoperative monitoring in predicting postoperative neurological deficits during PCF. SUMMARY OF BACKGROUND DATA: We calculated the predictive value, including sensitivity and specificity, of changes in SSEPs to identify neurological deficits postoperatively. We used a receiver operating characteristic (ROC) curve with SSEP categories as cutoff values to further evaluate the diagnostic accuracy of change in SSEPs and postoperative neurological deficit. METHODS: All patients had preposition baselines and continuous SSEP monitoring throughout the surgery. Statistical analysis was completed using SPSS version 22 (IBM Corp., Armonk, NY). RESULTS: Age and sex did not influence outcomes. Obesity affected patient outcome. The SSEP categories of significant changes and loss of responses resulted in a sensitivity/specificity of 0.30/0.96 and 0.16/0.98, respectively. The receiver operating characteristic curve has an area under the curve for significant change in/loss of SSEPs of 0.62/0.65 with a 95% confidence interval of 0.525 to 0.714/0.509 to 0.797. CONCLUSION: Significant SSEP changes during PCF are a very specific but poorly sensitive indicator of postoperative neurological deficits. The odds ratio for significant changes in SSEPs and loss of waveforms was 9.80 and 11.82, respectively, with a 95% confidence interval of 4.695 to 20.46 and 4.45 to 31.41, respectively. LEVEL OF EVIDENCE: 1.

Intraoperative Neurophysiological Monitoring of the Laryngeal Nerves During Anterior Neck Surgery: A Review.

Contributions to the literature on intraoperative neuro monitoring (IONM) during endocrine and head and neck surgery have increased over recent years. Organizational support for neural monitoring during surgery is becoming evident and is increasingly recognized as an adjunct to visual nerve identification. A comprehensive understanding of the role of IONM for prevention of nerve injuries is critical to maximize safety during surgery of the anterior compartment of the neck. This review will explore the potential advantages of IONM to improve the outcomes among patients undergoing anterior neck surgery.

Perioperative stroke after carotid endarterectomy: etiology and implications.

BACKGROUND: Carotid endarterectomy (CEA) is the procedure of choice for reducing the risk of stroke in both symptomatic and asymptomatic carotid artery stenoses. Stroke is associated with significant morbidity and mortality peri-operatively (2-3 %). Our primary aim is to evaluate the etiology of these strokes after CEA and their impact on morbidity by comparing the length of stay in the hospital. METHODS: A total of 584 patients with documented neurological status evaluations who underwent CEAs were included in the study. Neurophysiological monitoring data was obtained during CEA for carotid stenosis included eight-channel electroencephalography (EEG) and upper extremity somatosensory evoked potentials (SSEPs). RESULTS: Twenty-one (3.595 %) patients had strokes in the perioperative period and they were more likely to have left-sided surgery (p = 0.008), intraoperative monitoring (IOM) changes (p < 0.001), an intraoperative shunt placed (p = 0.0002) or a hospital stay longer than 5 days (p = 0.0042). Unilateral anterior circulation ischemic stroke were the most common in our series. In a logistic regression model, left-sided surgery was shown to be 4.78 times more likely to be associated with perioperative stroke (1.50-15.27; p = 0.008) while intraoperative shunts were 11.85 times more likely to have strokes (3.97-35.34; p < 0.0001). Patients with stenosis greater than 70 % were 6.67 times less likely to have a stroke (0.04-0.59; p = 0.007). CONCLUSIONS: Ischemic anterior circulation strokes are the most common type of post-operative neurological changes in patients undergoing CEA. Intraoperative shunt placement was a strong predictor of perioperative strokes. Since shunts are only placed following intraoperative monitoring changes, SSEPs and EEG can therefore function as a biomarker of cerebral hypo-perfusion.

Diagnostic accuracy of somatosensory evoked potential and electroencephalography during carotid endarterectomy.

BACKGROUND AND PURPOSE: Perioperative stroke risk following carotid endarterectomy (CEA) is reported to be approximately 2-3%. The diagnostic accuracies of intraoperative EEG and SSEP monitoring during CEA have been studied separately. However, to date, the effectiveness of simultaneous EEG and SSEP monitoring during CEA has only been evaluated in small study populations. This study examined the diagnostic accuracy of combined EEG and SSEP monitoring in a large (N = 1165) patient population. METHODS: This study included 1165 patients who underwent CEA from 2000 to 2012 at the University of Pittsburgh Medical Center. The sensitivities, specificities, and diagnostic odds ratio of EEG and SSEP monitoring methods were examined separately and together. Receiver operating characteristic curves were plotted to assess sensitivity and specificity of single and combined Intraoperative monitoring (IONM) methods. RESULTS: Maximum sensitivity was obtained with multimodality monitoring with an IONM change in either EEG or SSEP of 50.00 (95% CI, 30.66-69.34). The specificity of simultaneous EEG and SSEP changes was 93.95 (95% CI, 92.28-95.35%). Maximum area under ROC curve obtained for IONM change in either EEG or SSEP was 0.660 (95% CI, 0.547-0.773, p-value 0.004). CONCLUSION: The diagnostic accuracy of multimodality IONM during CEA is higher than an approach using single modality IONM. Simultaneous EEG and SSEP monitoring improves the likelihood of detecting periprocedural strokes after CEA. Neuro protective therapies to prevent periprocedural strokes can be based on changes in SSEP and EEG during CEA.

Comparison of Subdermal Needle and Surface Adhesive Stimulating Electrodes for Somatosensory Evoked Potential Monitoring during Anterior Cervical Discectomy and Fusion.

INTRODUCTION: Needle stick injuries remain a physical and psychological burden to healthcare workers. Noninvasive surface adhesive stimulating electrodes used to generate somatosensory evoked potentials can help decrease this risk. METHODS: We performed a retrospective observational study of patients who underwent anterior cervical discectomy and fusion (ACDF) surgery to determine the utility and variability of using surface adhesive stimulating electrodes. Our analysis for utility compared alarm (significant changes) frequency, defined by established alarm criteria, between subdermal needle (Group I) and surface adhesive electrodes (Group II). We compared the variability by comparing the frequency of alarms based on establishing baselines during various stages of the procedure. RESULTS: Between Group I and Group II, no significant differences were found in demographic, age, number of levels decompressed and fused, and length of surgery variability. However, stimulation intensity was significantly higher in Group II. Significant differences in the mean frequency of alarm of cortical, subcortical, and Erb's somatosensory evoked potential (SSEP) responses for the upper extremities between the two groups were only observed for the upper left Erb's point amplitude (p = 0.03) at retraction and upper right cortical amplitude at incision (p = 0.02). The frequency of alarms of the amplitude of left ulnar cortical responses from SSEPs using surface adhesives when baselines were established at the beginning of the procedure, at the time of incision, and at placement of retractors were 13.83 % (±14.08%), 7.50 % (±7.56%) and 3.42 % (±3.48%), respectively. Comparatively, the frequencies of alarms of the amplitude of left ulnar cortical responses from SSEPs using needle electrodes were 18.07 % (±22.85%), 12.13 % (±17.30%) and 7.37 % (±11.82%), respectively. Similar results were observed from frequency for alarms from the right ulnar SSEPs. CONCLUSION: This study found little significant difference between the frequencies of alarm in patients who had SSEP responses obtained using surface adhesive electrodes when compared to needle electrodes. This lack of significant difference was observed even when alarms were established at various stages of the surgery before any major manipulation. For short procedures monitoring the upper extremities only, surface adhesive electrodes may provide a reliable alternative to invasive needle electrodes.

Intraoperative neurophysiological monitoring during endoscopic endonasal surgery for pediatric skull base tumors.

OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.

Value of intraoperative neurophysiological monitoring to reduce neurological complications in patients undergoing anterior cervical spine procedures for cervical spondylotic myelopathy.

The primary aim of this study was to conduct a systematic review of reports of patients with cervical spondylotic myelopathy and to assess the value of intraoperative monitoring (IOM), including somatosensory evoked potentials, transcranial motor evoked potentials and electromyography, in anterior cervical procedures. A search was conducted to collect a small database of relevant papers using key words describing disorders and procedures of interest. The database was then shortlisted using selection criteria and data was extracted to identify complications as a result of anterior cervical procedures for cervical spondylotic myelopathy and outcome analysis on a continuous scale. In the 22 studies that matched the screening criteria, only two involved the use of IOM. The average sample size was 173 patients. In procedures done without IOM a mean change in Japanese Orthopaedic Association score of 3.94 points and Nurick score by 1.20 points (both less severe post-operatively) was observed. Within our sub-group analysis, worsening myelopathy and/or quadriplegia was seen in 2.71% of patients for studies without IOM and 0.91% of patients for studies with IOM. Variations persist in the existing literature in the evaluation of complications associated with anterior cervical spinal procedures. Based on the review of published studies, sufficient evidence does not exist to make recommendations regarding the use of different IOM modalities to reduce neurological complications during anterior cervical procedures. However, future studies with objective measures of neurological deficits using a specific IOM modality may establish it as an effective and reliable indicator of injury during such surgeries.

The Incidence of Early Postoperative Conductive Hearing Loss after Microvascular Decompression of Hemifacial Spasm.

Objectives To evaluate the incidence and discuss the pathogenesis of early postoperative conductive hearing loss (CHL) after microvascular decompression (MVD) for hemifacial spasm (HFS). Design Pre- and postoperative audiogram data and brainstem auditory evoked potentials (BAEPs) from patients who had underwent MVD for HFS were analyzed. Setting The study was conducted at the University of Pittsburgh Medical Center. Participants MVD for HFS patients who had pre- and postoperative audiogram data, BAEP data, and normal structure of the external and middle ear were included in the study. Main Outcome Measures CHL was diagnosed if there was an air-bone gap in pure tone audiometry of at least 10 dB at 0.5, 1, 2, or 4 kHz. Results The incidence of early postoperative CHL in the ipsilateral ear was 18.7% postoperatively. No CHL was observed in the contralateral side. No significant relationship between CHL and intraoperative BAEP changes was found. Demographic parameters were not significantly different between groups with and without CHL. Conclusions Early postoperative CHL is a significant complication after MVD. Fluid entering the mastoid air cells and/or bone-dust deposition during craniotomy may result in CHL. Long-term audiograms will be needed to evaluate the risk factors that lead to permanent CHL.

Comorbid Medical Conditions in Vascular Dementia: A Matched Case-Control Study.

The objective of the study was to compare the presence of comorbid medical conditions between patients with a vascular dementia (VaD) and a control group, from the Integrated Healthcare Information Services (IHCIS) database. VaD was defined by the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes 290.40, 290.4, 290.41, 290.42, and, 290.43. An individual matching method was used to select the controls, which were matched to cases on a 15:1 ratio by age, gender, type of health plan, and pharmacy benefits. Alzheimer's disease, any other dementia or cognitive deficits associated were considered exclusion criteria. Among the IHCIS patients 60 years of age or older and full year of eligibility during 2010, there were 898 VaD patients, from which 63.6% were women. Concurrent presence of cerebrovascular disease, atherosclerosis, heart failure, and atrial fibrillation were found at 12.6, 4.6, 2.8, and 1.7 times higher in VaD patients, respectively. Compared to controls, VaD patients had more septicemia, injuries, lung diseases including chronic obstructive pulmonary disease, and urinary diseases (all with df = 897,1; p < 0.0001). The present study confirms that these four medical comorbidities are frequent complications of VaD and physicians should be alert to the presence of them in patients with VaD.

Reduction in high-frequency hearing loss following technical modifications to microvascular decompression for hemifacial spasm.

OBJECT: Microvascular decompression is a safe and effective procedure to treat hemifacial spasm, but the operation poses some risk to the patient's hearing. While severe sensorineural hearing loss across all frequencies occurs at a low rate in experienced hands, a recent study suggests that as many as one-half of patients who undergo this procedure may experience ipsilateral high-frequency hearing loss (HFHL), and as many as one-quarter may experience contralateral HFHL. While it has been suggested that drill-related noise may account for this finding, this study was designed to examine the effect of a number of techniques designed to protect the vestibulocochlear nerve from operative manipulation on the incidence of HFHL. METHODS: Pure-tone audiometry was performed both preoperatively and postoperatively on 67 patients who underwent microvascular decompression for hemifacial spasm during the study period. A change of greater than 10 dB at either 4 kHz or 8 kHz was considered to be HFHL. Additionally, the authors analyzed intraoperative brainstem auditory evoked potentials from this patient cohort. RESULTS: The incidence of ipsilateral HFHL in this cohort was 7.4%, while the incidence of contralateral HFHL was 4.5%. One patient (1.5%; also included in the HFHL group) experienced an ipsilateral nonserviceable hearing loss. CONCLUSIONS: The reduced incidence of HFHL in this study suggests that technical modifications including performing the procedure without the use of fixed retraction may greatly reduce, but not eliminate, the occurrence of HFHL following microvascular decompression for hemifacial spasm.