Lesion location and lesion creation affect outcomes after focused ultrasound thalamotomy.

MRI-guided focused ultrasound thalamotomy has been shown to be an effective treatment for medication refractory essential tremor. Here, we report a clinical-radiological analysis of 123 cases of MRI-guided focused ultrasound thalamotomy, and explore the relationships between treatment parameters, lesion characteristics and outcomes. All patients undergoing focused ultrasound thalamotomy by a single surgeon were included. The procedure was performed as previously described, and patients were followed for up to 1 year. MRI was performed 24 h post-treatment, and lesion locations and volumes were calculated. We retrospectively evaluated 118 essential tremor patients and five tremor-dominant Parkinson's disease patients who underwent thalamotomy. At 24 h post-procedure, tremor abated completely in the treated hand in 81 essential tremor patients. Imbalance, sensory disturbances and dysarthria were the most frequent acute adverse events. Patients with any adverse event had significantly larger lesions, while inferolateral lesion margins were associated with a higher incidence of motor-related adverse events. Twenty-three lesions were identified with irregular tails, often extending into the internal capsule; 22 of these patients experienced at least one adverse event. Treatment parameters and lesion characteristics changed with increasing surgeon experience. In later cases, treatments used higher maximum power (normalized to skull density ratio), accelerated more quickly to high power, and delivered energy over fewer sonications. Larger lesions were correlated with a rapid rise in both power delivery and temperature, while increased oedema was associated with rapid rise in temperature and the maximum power delivered. Total energy and total power did not significantly affect lesion size. A support vector regression was trained to predict lesion size and confirmed the most valuable predictors of increased lesion size as higher maximum power, rapid rise to high-power delivery, and rapid rise to high tissue temperatures. These findings may relate to a decrease in the energy efficiency of the treatment, potentially due to changes in acoustic properties of skull and tissue at higher powers and temperatures. We report the largest single surgeon series of focused ultrasound thalamotomy to date, demonstrating tremor relief and adverse events consistent with reported literature. Lesion location and volume impacted adverse events, and an irregular lesion tail was strongly associated with adverse events. High-power delivery early in the treatment course, rapid temperature rise, and maximum power were dominant predictors of lesion volume, while total power, total energy, maximum energy and maximum temperature did not improve prediction of lesion volume. These findings have critical implications for treatment planning in future patients.

Length of hospital stay after craniotomy for tumor: a National Surgical Quality Improvement Program analysis.

OBJECT Although the length of hospital stay is often used as a measure of quality of care, data evaluating the predictors of extended hospital stay after craniotomy for tumor are limited. The goals of this study were to use multivariate regression to examine which preoperative characteristics and postoperative complications predict a prolonged hospital stay and to assess the impact of length of stay on unplanned hospital readmission. METHODS Data were extracted from the National Surgical Quality Improvement Program (NSQIP) database from 2007 to 2013. Patients who underwent craniotomy for resection of a brain tumor were included. Stratification was based on length of hospital stay, which was dichotomized by the upper quartile of the interquartile range (IQR) for the entire population. Covariates included patient age, sex, race, tumor histology, comorbidities, American Society of Anesthesiologists (ASA) class, functional status, preoperative laboratory values, preoperative neurological deficits, operative time, and postoperative complications. Multivariate logistic regression with forward prediction was used to evaluate independent predictors of extended hospitalization. Thereafter, hierarchical multivariate logistic regression assessed the impact of length of stay on unplanned readmission. RESULTS The study included 11,510 patients. The median hospital stay was 4 days (IQR 3-8 days), and 27.7% (n = 3185) had a hospital stay of at least 8 days. Independent predictors of extended hospital stay included age greater than 70 years (OR 1.53, 95% CI 1.28%-1.83%, p < 0.001); African American (OR 1.75, 95% CI 1.44%-2.14%, p < 0.001) and Hispanic (OR 1.68, 95% CI 1.36%-2.08%) race or ethnicity; ASA class 3 (OR 1.52, 95% CI 1.34%-1.73%) or 4-5 (OR 2.18, 95% CI 1.82%-2.62%) designation; partially (OR 1.94, 95% CI 1.61%-2.35%) or totally dependent (OR 3.30, 95% CI 1.95%-5.55%) functional status; insulin-dependent diabetes mellitus (OR 1.46, 95% CI 1.16%-1.84%); hematological comorbidities (OR 1.68, 95% CI 1.25%-2.24%); and preoperative hypoalbuminemia (OR 1.78, 95% CI 1.51%-2.09%, all p ≤ 0.009). Several postoperative complications were additional independent predictors of prolonged hospitalization including pulmonary emboli (OR 13.75, 95% CI 4.73%-39.99%), pneumonia (OR 5.40, 95% CI 2.89%-10.07%), and urinary tract infections (OR 11.87, 95% CI 7.09%-19.87%, all p < 0.001). The C-statistic of the model based on preoperative characteristics was 0.79, which increased to 0.83 after the addition of postoperative complications. A length of stay after craniotomy for tumor score was created based on preoperative factors significant in regression models, with a moderate correlation with length of stay (p = 0.43, p < 0.001). Extended hospital stay was not associated with differential odds of an unplanned hospital readmission (OR 0.97, 95% CI 0.89%-1.06%, p = 0.55). CONCLUSIONS In this NSQIP analysis that evaluated patients who underwent craniotomy for tumor, much of the variance in hospital stay was attributable to baseline patient characteristics, suggesting length of stay may be an imperfect proxy for quality. Additionally, longer hospitalizations were not found to be associated with differential rates of unplanned readmission.

Automated quantification of spikes.

Methods for rapid and objective quantification of interictal spikes in raw, unprocessed electroencephalogram (EEG) samples are scarce. We evaluated the accuracy of a tailored automated spike quantification algorithm. The automated quantification was compared with the quantification by two board-certified clinical neurophysiologists (gold-standard) in five steps: 1) accuracy in a single EEG channel (5 EEG samples), 2) accuracy in multiple EEG channels and across different stages of the sleep-wake cycles (75 EEG samples), 3) capacity to detect lateralization of spikes (6 EEG samples), 4) accuracy after application of a machine-learning mechanism (11 EEG samples), and 5) accuracy during wakefulness only (8 EEG samples). Our method was accurate during all stages of the sleep-wake cycle and improved after the application of the machine-learning mechanism. Spikes were correctly lateralized in all cases. Our automated method was accurate in quantifying and detecting the lateralization of interictal spikes in raw unprocessed EEG samples.

Contrast-induced nephropathy in patients with aneurysmal subarachnoid hemorrhage.

INTRODUCTION: Patients with aneurysmal subarachnoid hemorrhage (SAH) frequently undergo multiple angiographic studies within a 48-h period. We sought to evaluate the impact of these repeated contrast loads on renal function. METHODS: We reviewed the records of a consecutive series of 104 patients with aneurysmal subarachnoid hemorrhage, most of whom underwent at least an initial CT angiogram and digital subtraction angiography. Six patients had baseline renal disease. Initial creatinine levels were compared to maximum levels over a subsequent 48-h period after their last angiographic study. We defined contrast-induced nephropathy (CIN) as an increase in creatinine of at least 0.3 from baseline. RESULTS: The mean change in creatinine following treatment was 0.05 ± 0.23, with three patients developing CIN (2.9%). In 2 cases of CIN, the creatinine increase was inconsequential (0.39 and 0.44). All patients with CIN had an early return of their creatinine to baseline; none required dialysis or suffered permanent sequelae as a result of these creatinine increases. There was no statistically significant difference in the rate of CIN in patients treated with microsurgical clipping (n = 85) as compared to those who underwent coiling (n = 19). CONCLUSION: Our results underscore the relative safety of the usage of multiple angiographic studies performed in patients with aneurysmal SAH, particularly in patients without baseline renal disease.

A Standardized Electrode Nomenclature for Stereoelectroencephalography Applications.

PURPOSE: Stereoelectroencephalography (SEEG) is widely performed on individuals with medically refractory epilepsy for whom invasive seizure localization is desired. Despite increasing adoption in many centers across the world, no standardized electrode naming convention exists, generating confusion among both clinical and research teams. METHODS: We have developed a novel nomenclature, named the Standardized Electrode Nomenclature for SEEG Applications system. Concise, unique, informative, and unambiguous labels provide information about entry point, deep targets, and relationships between electrodes. Inter-rater agreement was evaluated by comparing original electrode names from 10 randomly sampled cases (including 136 electrodes) with those prospectively assigned by four additional blinded raters. RESULTS: The Standardized Electrode Nomenclature for SEEG Application system was prospectively implemented in 40 consecutive patients undergoing SEEG monitoring at our institution, creating unique electrode names in all cases, and facilitating implantation design, SEEG recording and mapping interpretation, and treatment planning among neurosurgeons, neurologists, and neurophysiologists. The inter-rater percent agreement for electrode names among two neurosurgeons, two epilepsy neurologists, and one neurosurgical fellow was 97.5%. CONCLUSIONS: This standardized naming convention, Standardized Electrode Nomenclature for SEEG Application, provides a simple, concise, reproducible, and informative method for specifying the target(s) and relative position of each SEEG electrode in each patient, allowing for successful sharing of information in both the clinical and research settings. General adoption of this nomenclature could pave the way for improved communication and collaboration between institutions.

Subdural Pneumocephalus Aspiration Reduces Recurrence of Chronic Subdural Hematoma.

BACKGROUND: Chronic subdural hematoma (cSDH) is a common neurosurgical condition, with symptoms ranging from headaches to coma. Operative evacuation is the treatment of choice. Subdural reaccumulation leading to reoperation is a vexing postoperative complication. OBJECTIVE: To present a novel technique for intraoperative aspiration of pneumocephalus via a subdural drain following SDH evacuation as a method of reducing potential subdural space and promoting cerebral expansion, thereby decreasing SDH recurrence. METHODS: In this retrospective study, 15 patients who underwent operative evacuation of cSDH between 2008 and 2015 were assessed. Six patients underwent a small craniotomy with intraoperative pneumocephalus aspiration. These patients were matched by age, gender, and anticoagulation status to 9 patients who underwent evacuation of SDH without pneumocephalus aspiration. Quantitative volumetric analysis was performed on the preoperative, postoperative, and 1-mo follow-up computed tomography scan to assess the subdural volume. RESULTS: In the immediate postoperative period, there was no difference in the percentage of residual subdural fluid between the aspiration and control groups (0.291 vs 0.251; P = 1.00). There was a decrease in amount of pneumocephalus present when the aspiration technique was applied (0.182 vs 0.386; P = .041). At 1-mo follow-up, there was a decrease in the residual cSDH volume between the aspiration and the control groups (28.7 mL vs 60.8 mL; P = .011). The long-term evacuation rate was greater in the aspiration group (75.4% vs 51.6%; P = .015). CONCLUSION: Intraoperative aspiration of cSDH cavity is a safe technique that may enhance cerebral expansion and reduce likelihood of cSDH recurrence.

Clinical Utility of Preoperative Bilingual Language fMRI Mapping in Patients with Brain Tumors.

BACKGROUND AND PURPOSE: Previous literature has demonstrated disparity in the postoperative recovery of first and second language function of bilingual neurosurgical patients. However, it is unclear to whether preoperative brain mapping of both languages is needed. In this study, we aimed to evaluate the clinical utility of language task functional MRI (fMRI) implemented in both languages in bilingual patients. METHODS: We retrospectively examined fMRI data of 13 bilingual brain tumor patients (age: 23 to 59 years) who performed antonym generation task-based fMRIs in English and non-English language. The usefulness of bilingual language mapping was evaluated using a structured survey administered to 5 neurosurgeons. Additionally, quantitative comparison between the brain activation maps of both languages was performed. RESULTS: Survey responses revealed differences in raters' surgical approach, including asleep versus awake surgery and extent of resection, after viewing the language fMRI maps. Additional non-English fMRI led to changes in surgical decision-making and bettered localization of language areas. Quantitative analysis revealed an increase in laterality index (LI) in non-English fMRI compared to English fMRI. The Dice coefficient demonstrated fair overlap (.458 ± .160) between the activation maps. CONCLUSION: Bilingual fMRI mapping of bilingual patients allows to better appreciate functionally active language areas that may be neglected in single language mapping. Utility of bilingual mapping was supported by changes in both surgical approach and LI measurements, suggesting its benefit on preoperative language mapping.

Long-term outcomes of lumbar microdiscectomy in the pediatric population: a large single-institution case series.

OBJECTIVE: Few studies describe long-term functional outcomes of pediatric patients who have undergone lumbar microdiscectomy (LMD) because of the rarity of pediatric disc herniation and the short follow-up periods. The authors analyzed risk factors, clinical presentation, complications, and functional outcomes of a single-institution series of LMD patients over a 19-year period. METHODS: A retrospective case series was conducted of pediatric LMD patients at a large pediatric academic hospital from 1998 to 2017. The authors examined premorbid risk factors, clinical presentation, physical examination findings, type and duration of conservative management, indications for surgical intervention, complications, and postoperative outcomes. RESULTS: Over the 19-year study period, 199 patients underwent LMD at the authors' institution. The mean age at presentation was 16.0 years (range 12-18 years), and 55.8% were female. Of these patients, 70.9% participated in competitive sports, and among those who did not play sports, 65.0% had a body mass index greater than 25 kg/m2. Prior to surgery, conservative management had failed in 98.0% of the patients. Only 3 patients (1.5%) presented with cauda equina syndrome requiring emergent microdiscectomy. Complications included 4 cases of postoperative CSF leak (2.0%), 1 case of a noted intraoperative CSF leak, and 3 cases of wound infection (1.5%). At the first postoperative follow-up appointment, minimal or no pain was reported by 93.3% of patients. The mean time to return to sports was 9.8 weeks. During a mean follow-up duration of 8.2 years, 72.9% of patients did not present again after routine postoperative appointments. The total risk of reoperation was a rate of 7.5% (3.5% of patients underwent reoperation for the same level; 4.5% underwent adjacent-level decompression, and one patient [0.5%] ultimately underwent a fusion). CONCLUSIONS: Microdiscectomy is a safe and effective treatment for long-term relief of pain and return to daily activities among pediatric patients with symptomatic lumbar disc disease in whom conservative management has failed.

Keen's Point for External Ventricular Drainage in Traumatic Brain Injury Patients: An Uncommon Indication for An Old Technique.

BACKGROUND: In cases of severe traumatic brain injury, cerebrospinal fluid (CSF) diversion though an external ventricular drain (EVD) is a proven method to assist in the control of elevated intracranial pressure. Under normal circumstances, the EVD is placed in a frontal location. However, in cases of multifocal intracranial injury and swelling, collapse of the frontal horns of the lateral ventricles leads to frequent failure of frontal CSF drainage. In this series we describe the utility of the Keen's point EVD as a safe alternative to maintain continuous CSF diversion for patients in whom frontal drainage is not feasible. CASE DESCRIPTIONS: Three patients (ages 30-46 years) with diffuse intracranial injury following severe trauma were admitted to our neurointensive care unit. One of these patients had decompressive craniectomy before transfer, while the other 2 patients did not undergo any surgical procedures. Each of these patients had severe refractory elevation of intracranial pressure and significant frontal swelling, ultimately necessitating bedside placement of a Keen's point EVD. CONCLUSIONS: In all cases, we were able to reliably maintain continuous CSF diversion for an extended period of time. There was 1 mortality due to the severity of initial injuries. In the remaining 2 patients, intracranial pressure was able to be normalized following placement of the Keen point EVD. The Keen point EVD is a viable option to maintain continuous CSF drainage in patients with diffuse intracranial injury and should be considered in patients whom a frontal EVD cannot reliably maintain continuous drainage of CSF.

Body habitus, serum albumin, and the outcomes after craniotomy for tumor: a National Surgical Quality Improvement Program analysis.

OBJECTIVE Although there is a growing body of research highlighting the negative impact of obesity and malnutrition on surgical outcomes, few studies have evaluated these parameters in patients undergoing intracranial surgery. The goal of this study was to use a national registry to evaluate the association of body mass index (BMI) and hypoalbuminemia with 30-day outcomes after craniotomy for tumor. METHODS Adult patients who underwent craniotomy for tumor were extracted from the prospective National Surgical Quality Improvement Program registry. Patients were stratified by body habitus according to the WHO classification, as well as by preoperative hypoalbuminemia (< 3.5 g/dl). Multivariable logistic regression evaluated the association of body habitus and hypoalbuminemia with 30-day mortality, complications, and discharge disposition. Covariates included patient age, sex, race or ethnicity, tumor histology, American Society of Anesthesiology class, preoperative functional status, comorbidities (including hypertension and diabetes mellitus), and additional preoperative laboratory values. RESULTS Among the 11,510 patients included, 28.7% were classified as normal weight (BMI 18.5-24.9 kg/m2), 1.9% as underweight (BMI < 18.5 kg/m2), 33.4% as overweight (BMI 25.0-29.9 kg/m2), 19.1% as Class I obese (BMI 30.0-34.9 kg/m2), 8.3% as Class II obese (BMI 35.0-39.9 kg/m2), 5.5% as Class III obese (BMI ≥ 40.0 kg/m2), and 3.1% had missing BMI data. In multivariable regression models, body habitus was not associated with differential odds of mortality, postoperative stroke or coma, or a nonroutine hospital discharge. However, the adjusted odds of a major complication were significantly higher for Class I obese (OR 1.28, 99% CI 1.01-1.62; p = 0.008), Class II obese (OR 1.53, 99% CI 1.13-2.07; p < 0.001), and Class III obese (OR 1.67, 99% CI 1.19-2.36; p < 0.001) patients compared with those of normal weight; a dose-dependent effect was seen, with increased effect size with greater adiposity. The higher odds of major complications was primarily due to significantly increased odds of a venous thromboembolism in overweight and obese patients, as well as of a surgical site infection in those with Class II or III obesity. Additionally, 41.0% of patients had an albumin level ≥ 3.5 g/dl, 9.6% had hypoalbuminemia, and 49.4% had a missing albumin value. Hypoalbuminemia was associated with significantly higher odds of mortality (OR 1.91, 95% CI 1.41-2.60; p < 0.001) or a nonroutine hospital discharge (OR 1.46, 95% CI 1.21-1.76; p < 0.001). CONCLUSIONS In this National Surgical Quality Improvement Program analysis evaluating patients who underwent craniotomy for tumor, body habitus was not associated with differential mortality or neurological complications. However, obese patients had increased odds of a major perioperative complication, primarily due to higher rates of venous thromboembolic events and surgical site infections. Preoperative hypoalbuminemia was associated with increased odds of mortality and a nonroutine hospital discharge, suggesting that serum albumin may have utility in stratifying risk preoperatively in patients undergoing craniotomy.

Intraoperative real-time MRI-guided stereotactic biopsy followed by laser thermal ablation for progressive brain metastases after radiosurgery.

Stereotactic radiosurgery is one of the treatment options for brain metastases. However, there are patients who will progress after radiosurgery. One of the potential treatments for this subset of patients is laser ablation. Image-guided stereotactic biopsy is important to determine the histopathological nature of the lesion. However, this is usually based on preoperative, static images, which may affect the target accuracy during the actual procedure as a result of brain shift. We therefore performed real-time intraoperative MRI-guided stereotactic aspiration and biopsies on two patients with symptomatic, progressive lesions after radiosurgery followed immediately by laser ablation. The patients tolerated the procedure well with no new neurologic deficits. Intraoperative MRI-guided stereotactic biopsy followed by laser ablation is safe and accurate, providing real-time updates and feedback during the procedure.

Basilar Invagination: Case Report and Literature Review.

BACKGROUND: Basilar invagination is a rare clinical condition characterized by upward protrusion of the odontoid process into the intracranial space, leading to bulbomedullary compression. It is often encountered in adults with rheumatoid arthritis. Transoral microscopic or endonasal endoscopic decompression may be pursued, with or without posterior fixation. We present a case of basilar invagination with C1-C2 autofusion and discuss an algorithm for choice of anterior versus posterior approaches. CASE DESCRIPTION: A 47-year-old woman with rheumatoid arthritis presented with severe occipital and cervical pain, dysphagia, hoarseness, and arm paresthesias. Findings on magnetic resonance imaging revealed moderate cranial settling with the odontoid indenting the ventral medulla but no posterior compression. Computed tomography demonstrated bony fusion at C1-C2 without lateral sag. Given autofusion of C1-C2 in proper occipitocervical alignment and the absence of posterior compression, the patient underwent endoscopic endonasal odontoidectomy without further posterior fusion, with satisfactory resolution of symptoms. CONCLUSION: Endoscopic endonasal odontoidectomy offers a safe and effective method for anterior decompression of basilar invagination. Preoperative assessment for existing posterior fusion, absence of posterior compression, and preservation of the anterior C1 ring during operative decompression help stratify the need for lone anterior approach versus a combined anterior and posterior treatment.