Susceptibility-Weighted MRI Approximates Intraoperative Microelectrode Recording During Deep Brain Stimulation of the Subthalamic Nucleus for Parkinson's Disease.

BACKGROUND: Deep brain stimulation of the subthalamic nucleus (STN-DBS) for Parkinson's disease can be performed with intraoperative neurophysiological and radiographic guidance. Conventional T2-weighted magnetic resonance imaging sequences, however, often fail to provide definitive borders of the STN. Novel magnetic resonance imaging sequences, such as susceptibility-weighted imaging (SWI), might better localize the STN borders and facilitate radiographic targeting. We compared the radiographic location of the dorsal and ventral borders of the STN using SWI with intraoperative microelectrode recording (MER) during awake STN-DBS for Parkinson's disease. METHODS: Thirteen consecutive patients who underwent placement of 24 STN-DBS leads for Parkinson's disease were analyzed retrospectively. Preoperative targeting was performed with SWI, and MER data were obtained from intraoperative electrophysiology records. The boundaries of the STN on SWI were identified by a blinded investigator. RESULTS: The final electrode position differed significantly from the planned coordinates in depth but not in length or width, indicating that MER guided the final electrode depth. When we compared the boundaries of the STN by MER and SWI, SWI accurately predicted the entry into the STN but underestimated the length and ventral boundary of the STN by 1.2 mm. This extent of error approximates the span of a DBS contact and could affect the placement of directional contacts within the STN. CONCLUSIONS: MER might continue to have a role in STN-DBS. This could potentially be mitigated by further refinement of imaging protocols to better image the ventral boundary of the STN.

Thermal Damage Estimate Artifact Following Antecedent Biopsy: A Case Report.

MR-guided laser interstitial therapy (MRgLITT) is becoming more commonly used for minimal access approaches to intracranial lesions of all etiologies. The short-term safety profile of MRgLITT is favorable compared with sweeping incisions and open craniotomies, especially for lesions located in deep, periventricular, and highly eloquent areas. The Visualase software (Medtronic Inc., Minneapolis, MN, USA) has multiple adaptations to assist with this safety margin, including the thermal damage estimate (TDE), which applies predictive mathematical modeling to a two-dimensional (2D) graphical representation. TDE has been shown to highly correlate with actual tissue destruction in a priori MRgLITT cases and to anecdotally be imprecise when MRgLITT is combined with biopsy. We present a case regarding a 17-year-old male patient with intractable focal epilepsy. He underwent stereotactic biopsy and then ablation where it was shown that TDE is ~35% larger in the coronal plane than in the actual ablation zone. Air may have caused this artifact in the biopsy cavity, which affected the proton resonance frequency (PRF) and caused TDE pigment deposition. We believe in the need for a more comprehensive understanding and investigation regarding this TDE artifact. Future prospective studies into MRgLITT should attend carefully in cases where it is combined with biopsy.

Predictors of Seizure Freedom in Pediatric Low-Grade Gliomas.

OBJECTIVE: Pediatric low-grade gliomas (LGGs) are found in approximately one to three percent of patients with childhood epilepsy. Epilepsy in these patients is often medically refractory and therefore represents a unique cohort with significant morbidity from concomitant pathology. Similar studies in adult patients with low-grade gliomas have identified predictors of seizure freedom including gross-total resection, preoperative seizure control on antiepileptic medication and duration of seizures of less than one year. This study aims to identify similar predictors of seizure freedom in operatively managed pediatric LGGs. METHODS: A retrospective chart review was performed for patients diagnosed with World Health Organization (WHO) Grade I and II gliomas in patients ≤18 years old at a single institution (Indiana University School of Medicine at Riley Hospital for Children in Indianapolis, IN) from 2007-2017. Infratentorial and purely intraventricular lesions were excluded. WHO classification and histologic diagnosis were based on surgical pathology. Tumor grade, location, laterality, seizure status at presentation, and AED requirements pre- and post-operatively were recorded. Chi-squared analyses for independence were performed controlling for age at presentation, resection extent, seizure type, and Engel Class for seizure freedom post-operatively. RESULTS: Forty-two patients met the inclusion criteria. Preoperative seizures were observed in 23 patients (55%). Presentation with preoperative seizures was highly associated with continued seizure burden post-operatively, independent of the extent of surgical resection. Supratentorial location and the administration of prophylactic pre- and post-operative AEDs were associated with Engel Class I seizure freedom. Temporal location was not significantly associated with medically refractory epilepsy compared with extra-temporal locations. CONCLUSIONS: In our cohort of pediatric LGGs, we find that patients that did not initially present with seizures and those who were treated with prophylactic pre- and post-operative AEDs, were more likely to achieve Engel Class I seizure freedom post-operatively. Tumors located in the temporal location were not significantly associated with a higher seizure burden than other supratentorial, extra-temporal tumors. Neither extent of resection nor electrocorticography-guided resection correlated with improved seizure freedom outcomes during glioma resection.

GammaTile for Gliomas: A Single-Center Case Series.

GammaTile® (GT Medical Technologies, Tempe, Arizona) is a surgically targeted radiation source, approved by FDA for brachytherapy in primary and secondary brain neoplasms. Each GammaTile is composed of a collagen sponge with four seeds of cesium 131 and is particularly useful in recurrent tumors. We report our early experience in seven patients with recurrent gliomas to assess this type of brachytherapy with particular attention to ease of use, complication, and surgical planning. This study represents a retrospective chart review of surgical use and early clinical outcomes of GammaTile in recurrent gliomas. The number of tiles was planned using pre-operative imaging and dosimetry was planned based on post-operative imaging. Patients were followed during their hospital stay and were followed up after discharge. Parameters such as case length, resection extent, complication, ICU length of stay (LOS), hospital LOS, pre-operative Glasgow Coma Scale (GCS), immediate post-operative GCS, post-operative imaging findings, recurrence at follow-up, length of follow-up, and dosimetry were collected in a retrospective manner. Seven patients were identified that met the inclusion criteria. Two patients were diagnosed with recurrent glioblastoma multiforme (GBM), one lower-grade glioma that recurred as a GBM, one GBM that recurred as a gliosarcoma, and two recurrent oligodendrogliomas. We found that operation time, ICU LOS, hospital LOS, pre- and post-operative GCS, and post-operative complications were within the expected ranges for tumor resection patients. Further, dosimetry data suggests that six out of seven patients received adequate radiation coverage, with the seventh having implantation limitations due to nearby organs at risk. We report no postoperative complications that can be attributed to the GammaTiles themselves. In our cohort, we report seven cases where GammaTiles were implanted in recurrent gliomas. No implant-related post-operative complications were identified. This early data suggests that GammaTile can be a safe form of brachytherapy in recurrent gliomas.

Symptomatic Cerebral Vasospasm After Transsphenoidal Tumor Resection: Two Case Reports and Systematic Literature Review.

Cerebral vasospasm is a rare life-threatening complication of transsphenoidal surgery (TSS). We report our experience with two cases of symptomatic vasospasm after endoscopic TSS, alongside a systematic review of published cases. Two patients who underwent endoscopic TSS for resection of a tuberculum sella meningioma (case 1) and pituitary adenoma (case 2) developed symptomatic vasospasm. Clinical variables, including demographics, histopathology, the extent of subarachnoid hemorrhage (SAH), diabetes insipidus (DI), day of vasospasm, vasospasm symptoms, vessels involved, management, and clinical outcome, were retrospectively extracted. We subsequently reviewed published cases of symptomatic post-TSS vasospasm. Including our two cases, we identified 34 reported cases of TSS complicated by symptomatic vasospasm. Female patients accounted for 20 (58.8%) of 34 cases. The average age was 48.1 ± 12.9 years. The majority of patients exhibited postoperative SAH (70.6%). The average delay to vasospasm presentation was 8.5 ± 3.6 days. The majority of patients exhibited vasospasm in multiple vessels, typically involving the anterior circulation. Hemodynamic augmentation with hemodilution, hypertension, and hypervolemia was the most common treatment. Death occurred in six (17.6%) of 34 patients. Common deficits included residual extremity weakness (17.6%), pituitary insufficiency (8.8%), and cognitive deficits (8.8%). Symptomatic vasospasm is a rare, potentially fatal complication of TSS. The most consistent risk factor is SAH. Early diagnosis requires a high index of suspicion when confronted with intractable DI, acute mental status change, or focal deficits in the days after TSS. Morbidity and death are significant risks in patients with this complication.

Hispanic ethnicity and complication profile following laparoscopic and open cholecystectomy.

BACKGROUND: Hispanic ethnicity is associated with increased incidence of gallbladder disease. Additionally, ethnicity has been shown to be an outcome determinant in several conditions and procedures but has never been studied as a potential determinant of morbidity or mortality after laparoscopic or open cholecystectomy. METHODS: Using the American College of Surgeons National Surgical Quality Improvement Program database, patients who underwent cholecystectomy and related procedures were studied in Hispanic and non-Hispanic cohorts. Mortality and postoperative complication rates were calculated and adjusted for patient demographics and comorbidities through multivariate analysis. RESULTS: Hispanics had decreased morbidity following cholecystectomy as compared to non-Hispanics on univariate analysis in combined, laparoscopic, and open cohorts (RR 0.64, P value < 0.001; 0.68, <0.001; 0.77, <0.001, respectively). The reduction was not found to be statistically significant in multivariate analysis. A similar reduction was seen for mortality (RR 0.30, <0.001; 0.39, <0.001; 0.28, <0.001, respectively) which remained on multivariate analysis in both combined and open cohorts (RR 0.63, 0.008 and 0.48, 0.021, respectively). Additionally, the rates of several postoperative complications were found to be reduced in Hispanic patients. Though our study demonstrates a lower rate of established comorbidities for poor outcomes in Hispanics, after adjustment in multivariate analysis, the entirety of the reduced risk could not be accounted for. CONCLUSIONS: While the Hispanic cohort has an increased incidence in gallbladder disease as compared to non-Hispanics, the complication, morbidity, and mortality rates are lower in unadjusted analysis. With adjustment, morbidity was not statistically significant and mortality was only significant in combined and open cohorts. This suggests that increased incidence rates do not equate with worse outcomes, but Hispanic ethnicity may be associated with better outcomes.

Ethnic disparities in traumatic brain injury care referral in a Hispanic-majority population.

BACKGROUND: Functional outcomes after traumatic brain injury (TBI) can be significantly improved by discharge to posthospitalization care facilities. Many variables influence the discharge disposition of the TBI patient, including insurance status, patient condition, and patient prognosis. The literature has demonstrated an ethnic disparity in posthospitalization care referral, with Hispanics being discharged to rehabilitation and nursing facilities less often than non-Hispanics. However, this relationship has not been studied in a Hispanic-majority population, and thus, this study seeks to determine if differences in neurorehabilitation referrals exist among ethnic groups in a predominately Hispanic region. METHODS: This study is a retrospective cohort that includes 1128 TBI patients who presented to University Medical Center El Paso, Texas, between the years 2005 and 2015. The patients' age, sex, race, residence, admission Glasgow Coma Scale (GCS), GCS motor, Injury Severity Score (ISS), hospital and intensive care unit length of stay (LOS), mechanism of injury, and discharge disposition were analyzed in univariate and multivariate models. RESULTS: Our study population had an insurance rate of 55.5%. Insurance status and markers of injury severity (hospital LOS, intensive care unit LOS, ISS, GCS, and GCS motor) were predictive of discharge disposition to rehabilitation facilities. The study population was 70% Hispanic, yet Hispanics were discharged to rehabilitation facilities (relative risk: 0.56, P: 0.001) and to long-term acute care/nursing facilities (relative risk: 0.35, P < 0.0001) less than non-Hispanics even after LOS, ISS, ethnicity, insurance status, and residence were adjusted for in multivariate analysis. CONCLUSIONS: This study suggests that patients of different ethnicities but comparable traumatic severity and insurance status receive different discharge dispositions post-TBI even in regions in which Hispanics are the demographic majority.