Sanjeet S. Grewal

Overdrainage shunt complications in idiopathic normal-pressure hydrocephalus and lumbar puncture opening pressure

OBJECT Management of idiopathic normal-pressure hydrocephalus (iNPH) is hard because the diagnosis is difficult and shunt surgery has high complication rates. An important complication is overdrainage, which often can be treated with adjustable-shunt valve manipulations but also may result in the need for subdural hematoma evacuation. The authors evaluated shunt surgery overdrainage complications in iNPH and their relationship to lumbar puncture opening pressure (LPOP). METHODS The authors reviewed the charts of 164 consecutive patients with iNPH who underwent shunt surgery at their institution from 2005 to 2011. They noted age, sex, presenting symptoms, symptom duration, hypertension, body mass index (BMI), imaging findings of atrophy, white matter changes, entrapped sulci, LPOP, valve opening pressure (VOP) setting, number of valve adjustments, serious overdrainage (subdural hematoma requiring surgery), radiological overdrainage (subdural hematomas or hygroma seen on postoperative imaging), clinical overdrainage (sustained or postural headache), other complications, and improvements in gait, urine control, and memory. RESULTS Eight patients (5%) developed subdural hematomas requiring surgery. All had an LPOP of greater than 160 mm H2O and an LPOP-VOP of greater than 40 mm H2O. Radiological overdrainage was more common in those with an LPOP of greater than 160 mm H2O than in those with an LPOP of less than 160 mm H2O (38% vs. 21%, respectively; p = 0.024). The BMI was also significantly higher in those with an LPOP of greater than 160 mm H2O (median 30.2 vs. 27.0, respectively; p = 0.005). CONCLUSIONS Serious overdrainage that caused subdural hematomas and also required surgery after shunting was related to LPOP and LPOP-VOP, which in turn were related to BMI. If this can be replicated, individuals with a high LPOP should have their VOP set close to the LPOP, or even higher. In doing this, perhaps overdrainage complications can be reduced.

Influence of Body Mass Index and Age on Functional Outcomes in Patients With Subarachnoid Hemorrhage

BACKGROUND Recent studies have highlighted the obesity paradox where patients with obesity have a greater chance of survival than patients with normal weight. OBJECTIVE To investigate the association between body mass index (BMI) and age with severity of subarachnoid hemorrhage (SAH) and functional outcome. METHODS We retrospectively reviewed the charts of 274 consecutive patients admitted with SAH between June 2008 and June 2012. Data collected included patient demographic features (age, sex, BMI), severity of SAH at admission (Fisher grade, Hunt and Hess grade, Glasgow Coma Scale score, and the World Federation of Neurosurgeons Scale score), as well as functional outcome measured by the modified Rankin Scale (mRS) by death or discharge. RESULTS The median age was 57 years (range, 18-99), and 62% were female; the median BMI was 27 (range, 14.3-55.1). On multivariate analysis adjusting for age and sex, there was no evidence of an association between BMI and Hunt and Hess grade, Fisher grade, World Federation of Neurosurgeons Scale score, Glasgow Coma Scale score, or mRS score (all P≥.17). On multivariate analysis adjusting for BMI and sex, there was evidence of a higher mRS score (P<.001) and lower WFNS grade (P=.016) in older patients, with no significant association observed between age and the remaining 3 measures of SAH severity (all P≥.10). CONCLUSION The results of our study indicate that BMI is not noticeably associated with severity of bleeding or functional outcome in patients with SAH. This finding was discovered after performing a multivariate analysis adjusting for age where older age was associated with worsened severity and outcome.

Silent ischemic events after Pipeline embolization device: a prospective evaluation with MR diffusion-weighted imaging

Background The development of ischemic events is relatively common after endovascular interventions, and flow diverters may pose a particular threat owing to their increased technical complexity and high metal content. Objective To investigate the incidence and potential risk factors for thromboembolic lesions after treatment with a Pipeline embolization device (PED). Methods This prospective study included a total of 59 patients electively treated with a PED over 12 months. Postprocedural diffusion-weighted imaging sequences of the brain were obtained 24 h after interventions to detect ischemic lesions. Demographic data, aneurysm characteristics, antiplatelet management, and perioperative data were correlated with the rate of ischemic events. Results The incidence of silent ischemic events after use of a PED was 62.7% (37 patients) and neurological symptoms occurred in 8.1% of affected patients. Development of ischemic events was significantly associated with older patients (≥60 years; p=0.038). Routine use of platelet function assays and newer P2Y12 receptor inhibitors (ticagrelor) were not associated with fewer thromboembolic events. Conclusions Thromboembolic events are relatively common after treatment with a PED with an incidence comparable to stent-assisted and conventional coiling but the risk of neurological morbidity from ischemic burden is low. Older patients are at particularly increased risk of thromboembolic events.

The Relationship Between Serum Neuron-Specific Enolase Levels and Severity of Bleeding and Functional Outcomes in Patients With Nontraumatic Subarachnoid Hemorrhage.

BACKGROUND The value of neuron-specific enolase (NSE) in predicting clinical outcomes has been investigated in a variety of neurological disorders. OBJECTIVE To investigate the associations of serum NSE with severity of bleeding and functional outcomes in patients with subarachnoid hemorrhage (SAH). METHODS We retrospectively reviewed the records of patients with SAH from June 2008 to June 2012. The severity of SAH bleeding at admission was measured radiographically with the Fisher scale and clinically with the Glasgow Coma Scale, Hunt and Hess grade, and World Federation of Neurologic Surgeons scale. Outcomes were assessed with the modified Rankin Scale at discharge. RESULTS We identified 309 patients with nontraumatic SAH, and 71 had NSE testing. Median age was 54 years (range, 23-87 years), and 44% were male. In multivariable analysis, increased NSE was associated with a poorer Hunt and Hess grade (P = .003), World Federation of Neurologic Surgeons scale score (P < .001), and Glasgow Coma Scale score (P = .003) and worse outcomes (modified Rankin Scale at discharge; P = .001). There was no significant association between NSE level and Fisher grade (P = .81) in multivariable analysis. CONCLUSION We found a significant association between higher NSE levels and poorer clinical presentations and worse outcomes. Although it is still early for any relevant clinical conclusions, our results suggest that NSE holds promise as a tool for screening patients at increased risk of poor outcomes after SAH.

Neuropsychological outcomes following stereotactic laser amygdalohippocampectomy

OBJECTIVE The objective was to analyze neuropsychological testing data from 15 patients before and after stereotactic laser ablation surgery for temporal lobe epilepsy and to describe the seizure outcomes after stereotactic laser ablation surgery. METHODS A retrospective review of 15 patients who underwent stereotactic laser ablation and who also underwent neuropsychological testing before and after surgery was performed. Verbal and visual memory was assessed in all 15 patients using California Verbal Learning Test and Wechsler Memory Scale IV. Naming was assessed in 9 of 15 patients using the Boston Naming Test. Statistical analysis was performed to determine clinically significant changes using previously validated reliable change indices and proprietary Advanced Clinical Solutions software. Seizure outcome data were evaluated using Engel classification. RESULTS Postsurgery neuropsychological evaluation demonstrated that all 15 patients experienced at least 1 clinically significant decline in either verbal or visual memory. Ten patients in this series, including five with dominant-hemisphere surgery, demonstrated decline in delayed memory for narrative information (Logical Memory II). By contrast, the Boston Naming Test demonstrated more favorable results after surgery. Two of nine patients demonstrated a clinically significant increase in naming ability, and only one of nine patients demonstrated a clinically significant decline in naming ability. With at least 6months of follow-up after surgery, 33% reported seizure freedom. CONCLUSION Stereotactic laser ablation can result in clinically significant and meaningful decline in verbal and visual memory when comparing patients to their own presurgical baseline. Naming ability, conversely, is much less likely to be impacted by stereotactic laser ablation and may improve after the procedure.

Insurance correlates with improved access to care and outcome among glioblastoma patients

Background The current standard of care for glioblastoma (GBM) constitutes maximal safe surgical resection, followed by fractionated radiation and temozolomide. This treatment regimen is logistically burdensome, and in a health care system in which access to care is variable, there may be patients with worsened outcomes due to inadequate access to optimal treatment. Methods The National Cancer Database was queried for patients with diagnoses of GBM in 2006-2014. Patients were grouped according to insurance status: private insurance, Medicare, Medicaid, or uninsured. Treatments provided (surgery, radiation, and chemotherapy) were compared between groups in univariate and multivariable logistic regression analysis. Results A total of 61614 patients were analyzed. Compared with private insurance, the odds of surgery for Medicaid and uninsured patients were 0.72 (95% CI: 0.66-0.79) and 0.77 (95% CI: 0.69-0.87), respectively (P < 0.001). The multivariable odds of receiving radiotherapy were 0.91 (95% CI: 0.86-0.96), 0.62 (95% CI: 0.57-0.68), and 0.47 (95% CI: 0.43-0.52) for Medicare, Medicaid, and uninsured patients, respectively (all P < 0.001). In addition, the odds of receiving chemotherapy were 0.94 (95% CI: 0.89-0.99), 0.53 (95% CI: 0.49-0.57), and 0.41 (95% CI: 0.38-0.46) for Medicare, Medicaid, and uninsured patients, respectively (all P < 0.001). Conclusion Insurance status and type of insurance coverage appear to impact treatments rendered for GBM, independently of other variables. Furthermore, we find that such differential access to care significantly impacts survival. Ensuring adequate access to care for all patients with diagnoses of glioblastoma is critical to optimize survival, especially as therapies continue to advance.

Identification of arachnoid web with a relatively novel magnetic resonance imaging technique.

Arachnoid webs are described as intradural extramedullary transverse bands of arachnoid tissue that extend to the dorsal surface of the spinal cord, causingmass effect and dorsal indentation, and theyare often associatedwith syringomyelia [1].Although the precisemechanismof syrinx formation is unknown, dissection of the arachnoid web shrinks the syrinx and improves the symptoms [2,3]. Arachnoid webs are not easily visualized with conventional magnetic resonance imaging (MRI) or computed tomography (CT) myelography because of their comparatively thin width relative to other structures [2]. Other institutions have described the use of cardiac-gated phase-contrast cine-mode MRI in multiple axial planes to better identify these entities radiographically [2].We report the use of a heavily T2-weighted constructive interference in steady state (CISS) sequence to identify these lesions preoperatively. A 65-year-old man presented with worsening gait imbalance and exhibited evidence ofmyelopathy on physical examination. He had two significant neck injuries in his medical history, but was never diagnosed with a cervical fracture. Weperformed anMRIof the cervical spine that revealed an abnormal T2 hyperintensity within the lower cervical and upper thoracic spinal cord, from C6/C7 to T2 (Fig. 1). This was thought to reflect a combination of syrinx and either spinal cord edema or myelomalacia. There was also a focal

Magnetic Resonance guided Laser Interstitial Thermal Therapy (MRgLITT) vs Stereotactic Radiosurgery (SRS) for Medically Intractable Temporal Lobe Epilepsy (TLE) : A Systematic Review and Meta-Analysis of Seizure Outcomes and Complications

INTRODUCTION Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) and stereotactic radiosurgery (SRS) are 2 emerging minimally invasive procedures being increasingly used for surgical intervention in cases of medically intractable temporal lobe epilepsy (TLE). To date, no comparative analyses of these 2 procedures have been made. In the current study, we synthesized pooled data from existing studies in an attempt to present a systematic review and meta-analysis of seizure and clinical outcomes of the 2 procedures in patients with TLE. METHODS The Population, Intervention, Comparator, and Outcome (PICO) approach and Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed to perform an indirect meta-analysis of seizure and clinical outcomes between MRgLITT and SRS. Only studies reporting outcomes for patients with TLE were included in the current review. RESULTS A total of 19 studies were included in the final analysis, giving a total of 415 TLE patients. Of those studies, 9 were on MRgLITT, with a total of 250 patients (60%), and 10 were on SRS, with a total of 165 patients (40%). We found that the overall seizure freedom rate was comparable between the 2 procedures (MRgLITT 50%, 95% confidence interval [CI] 44% to 56%, vs. SRS 42%, 95% CI 27% to 59%, P = 0.39). Similarly, among patients with lesional pathologic conditions only, the seizure freedom rate was comparable between the 2 procedures (MRgLITT 62%, 95% CI 48% to 74%, vs. SRS 50%, 95% CI 37% to 64%, P = 0.23). Compared with SRS, MRgLITT was associated with lower complication rates (MRgLITT 20%, 95% CI 14% to 26% vs. SRS 32%, 95% CI 20% to 46%, P = 0.06) but similar reoperation rates (15%, 95% CI 9% to 22% vs. 27%, 95% CI 12% to 46%, P = 0.31). CONCLUSIONS As minimally invasive procedures continue to gain popularity for use in surgery for epilepsy, it is imperative to evaluate their efficacy and safety outcomes. In this study we pooled the data from existing studies to compare the seizure and clinical outcomes in patients with TLE undergoing MRgLITT and SRS. We found similar outcomes and complications between the 2 procedures.

Safety of Laser Interstitial Thermal Therapy in Patients With Pacemakers

BACKGROUND AND IMPORTANCE Laser interstitial thermal therapy (LiTT) has increasingly been used as a treatment option for medically refractory epilepsy, tumors, and radiation necrosis. The use of LiTT requires intraoperative magnetic resonance (MR) thermography. This can become an issue in patients with other implanted therapeutic devices such as pacemakers and vagal nerve stimulators due to concerns regarding increases in the specific absorption rate (SAR). This is a technical case report demonstrating a successfully and safely performed LiTT in a 1.5-T magnetic resonance imaging (MRI) in a patient with a pacemaker for mesial temporal sclerosis. CLINICAL PRESENTATION An 83-yr-old gentleman who had an implanted cardiac pacemaker presented with medically intractable epilepsy and was confirmed to have mesial temporal sclerosis on imaging. Video electroencephalography demonstrated concordant ipsilateral seizures and semiology. He underwent LiTT for ablation of the mesial temporal lobe. This was performed with the below described protocol with a cardiology nurse monitoring the patients cardiac condition and a physicist monitoring SAR, and MR imaging quality without any adverse events. CONCLUSION This study reports on a protocol of cardiac and MR SAR to safely perform MR-guided LiTT in the setting of traditional pacemakers in patients who are not pacemaker dependent.

Structural connectivity–based segmentation of the thalamus and prediction of tremor improvement following thalamic deep brain stimulation of the ventral intermediate nucleus

Objectives Traditional targeting methods for thalamic deep brain stimulation (DBS) performed to address tremor have predominantly relied on indirect atlas-based methods that focus on the ventral intermediate nucleus despite known variability in thalamic functional anatomy. Improvements in preoperative targeting may help maximize outcomes and reduce thalamic DBS–related complications. In this study, we evaluated the ability of thalamic parcellation with structural connectivity–based segmentation (SCBS) to predict tremor improvement following thalamic DBS. Methods In this retrospective analysis of 40 patients with essential tremor, hard segmentation of the thalamus was performed by using probabilistic tractography to assess structural connectivity to 7 cortical targets. The volume of tissue activated (VTA) was modeled in each patient on the basis of the DBS settings. The volume of overlap between the VTA and the 7 thalamic segments was determined and correlated with changes in preoperative and postoperative Fahn-Tolosa-Marin Tremor Rating Scale (TRS) scores by using multivariable linear regression models. Results A significant association was observed between greater VTA in the supplementary motor area (SMA) and premotor cortex (PMC) thalamic segment and greater improvement in TRS score when considering both the raw change (P = .001) and percentage change (P = .011). In contrast, no association was observed between change in TRS score and VTA in the primary motor cortex thalamic segment (P ≥ .19). Conclusions Our data suggest that greater VTA in the thalamic SMA/PMC segment during thalamic DBS was associated with significant improvement in TRS score in patients with tremor. These findings support the potential role of thalamic SCBS as an independent predictor of tremor improvement in patients who receive thalamic DBS.