Refining the predictive value of preoperative apparent diffusion coefficient (ADC) by whole-tumor analysis for facial nerve outcomes in vestibular schwannomas.

BACKGROUND: Apparent diffusion coefficient (ADC) in MRI has been shown to correlate with postoperative House-Brackmann (HB) scores in patients with vestibular schwannoma despite limited methodology. To rectify limitations of single region of interest (ROI) sampling, we hypothesize that whole-tumor ADC histogram analysis will refine the predictive value of this preoperative biomarker related to postoperative facial nerve function. METHODS: Of 155 patients who underwent resection of vestibular schwannoma (2014-2020), 125 patients were included with requisite clinical and radiographic data. After volumetric analysis and whole-tumor ADC histogram, regression tree analysis identified ADC cutoff for significant differences in HB grade. Outcomes were extent of resection, facial nerve function, hospital length of stay (LOS), and complications. RESULTS: Regression tree analysis defined three quantitative ADC groups (× 10-6 mm2/s) as high (> 2248.77; HB 1.7), mid (1468.44-2248.77; HB 3.1), and low (< 1468.44; HB 2.3) range (p 0.04). The mid-range ADC group had significantly worse postoperative HB scores and longer hospital LOS. Large tumor volume was independently predictive of lower rates of gross total resection (p <0.0001), higher postoperative HB score (p 0.002), higher rate of complications (p 0.04), and longer LOS (p 0.003). CONCLUSIONS: Whole-tumor histogram yielded a robust regression tree analysis that defined three ADC groups with significantly different facial nerve outcomes. This likely reflects tumor heterogeneity better than solid-tumor ROI sampling. Whole-tumor ADC warrants further study as a useful radiographic biomarker in patients with vestibular schwannoma who are considering surgical resection.

Traumatic brain injury and obesity induce persistent central insulin resistance.

Traumatic brain injury (TBI)-induced impairments in cerebral energy metabolism impede tissue repair and contribute to delayed functional recovery. Moreover, the transient alteration in brain glucose utilization corresponds to a period of increased vulnerability to the negative effects of a subsequent TBI. In order to better understand the factors contributing to TBI-induced central metabolic dysfunction, we examined the effect of single and repeated TBIs on brain insulin signalling. Here we show that TBI induced acute brain insulin resistance, which resolved within 7 days following a single injury but persisted until 28 days following repeated injuries. Obesity, which causes brain insulin resistance and neuroinflammation, exacerbated the consequences of TBI. Obese mice that underwent a TBI exhibited a prolonged reduction of Akt (also known as protein kinase B) signalling, exacerbated neuroinflammation (microglial activation), learning and memory deficits, and anxiety-like behaviours. Taken together, the transient changes in brain insulin sensitivity following TBI suggest a reduced capacity of the injured brain to respond to the neuroprotective and anti-inflammatory actions of insulin and Akt signalling, and thus may be a contributing factor for the damaging neuroinflammation and long-lasting deficits that occur following TBI.

Immunocompetent isolated cerebral mucormycosis presenting with obstructive hydrocephalus: illustrative case.

BACKGROUND: Isolated cerebral mucormycosis is rare in immunocompetent adults and is only sparsely reported to be associated with obstructive hydrocephalus. OBSERVATIONS: Here, the authors report a case of obstructive hydrocephalus secondary to central nervous system mucormycosis without other systems or rhino-orbital involvement and its technical surgical management. A 23-year-old, incarcerated, immunocompetent patient with history of intravenous (IV) drug use presented with syncope. Although clinical and radiographic findings failed to elucidate an infectious pathology, endoscopy revealed an obstructive mass lesion at the level of the third ventricle, which, on microbiological testing, was confirmed to be Rhizopus fungal ventriculitis. Perioperative cerebrospinal fluid diversion, endoscopic third ventriculostomy, endoscopic biopsy technique, patient outcomes, and the literature are reviewed here. The patient received intrathecal and IV amphotericin B followed by a course of oral antifungal treatment and currently remains in remission. LESSONS: The patient's unique presentation and diagnosis of isolated cerebral mucormycosis reveal this pathogen as a cause of ventriculitis and obstructive hydrocephalus in immunocompetent adult patients, even in the absence of infectious sequelae on neuroimaging.

Poverty: Not a Justification for Banning Physician-Assisted Death.

Many critics of the legalization of physician-assisted death oppose it in part because they fear it will further disadvantage those who are already economically disadvantaged. This argument points to a serious problem of how economic considerations can influence medical decisions, but in the context of PAD, the concern is not borne out. We will provide empirical evidence suggesting that concerns about money influence medical decisions throughout the full course of illness, but at the end of life, financial pressure is much more likely to influence a decision to pursue or reject aggressive life-extending care than it is to influence a request for PAD. We will also address the question of whether financial pressure as a result of being poor-particularly in the context of an inadequate social safety net-robs people of their autonomy, rendering their informed request and consent invalid. We argue that it does not. We will emphasize the impracticality and injustice of rejecting the role of poverty as a legitimate factor in decision-making, the irrational distinction between PAD and withdrawal of life-sustaining care, and the more appropriate focus on the great flaws in the American health care system.

Implications of Celiac Disease Among Patients Undergoing Gastric Bypass.

INTRODUCTION: Bariatric surgery is generally safe and effective, but co-existing malabsorptive processes may increase the risk of complications or nutritional deficiencies. Bariatric surgery has not been well studied in the setting of pre-existing celiac disease. MATERIALS AND METHODS: Patients who underwent Roux-en-Y gastric bypass (RYGB) from January 2002 to December 2015 were retrospectively reviewed for either diagnosis of or serum testing for celiac disease. Identified patients were re-reviewed for adherence to American Gastroenterological Association (AGA) diagnostic criteria. Patient demographics, operative data, and post-operative weight loss and nutritional parameters were collected. RESULTS: Of the > 12,000 patients who underwent bariatric surgery during this study period, there were 342 patients that had abnormal serology or pathology results. Expert review confirmed three patients (0.8%) with celiac disease diagnosed before RYGB procedure. All were female, with an average age of 33 years and a mean BMI of 44.07 kg/m2. At the time of surgery, two of the three patients were following a gluten-free diet. At 6 months follow-up, mean % excess weight loss was 76.5%. The patients following a gluten-free diet preoperatively continued post-operatively. No patients were anemic nor had vitamin B12 or iron deficiencies at 12-month follow-up. Two patients had vitamin D insufficiencies and responded to daily oral supplementation. CONCLUSION: Though many bariatric patients may carry a presumptive diagnosis of celiac disease, a small percentage of these meet AGA diagnostic criteria. RYGB appears safe in this population with comparable weight loss in non-celiac counterparts. Increased attention to vitamin D levels may be warranted post-operatively.