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OBJECTIVE In the absence of practical and reliable prognostic tools in intracranial tumor surgery, decisions regarding patient selection, patient information, and surgical management are usually based on neurosurgeons' clinical judgment, which may be influenced by personal experience and knowledge. The objective of this study was to assess the accuracy of the operating neurosurgeons' predictions about patients' functional levels after intracranial tumor surgery. METHODS In a prospective single-center study, the authors included 299 patients who underwent intracranial tumor surgery between 2011 and 2015. The operating neurosurgeons scored their patients' expected functional level at 30 days after surgery using the Karnofsky Performance Scale (KPS). The expected KPS score was compared with the observed KPS score at 30 days. RESULTS The operating neurosurgeons underestimated their patients' future functional level in 15% of the cases, accurately estimated their functional levels in 23%, and overestimated their functional levels in 62%. When dichotomizing functional levels at 30 days into dependent or independent functional level categories (i.e., KPS score < 70 or ≥ 70), the predictive accuracy was 80%, and the surgeons underestimated and overestimated in 5% and 15% of the cases, respectively. In a dichotomization based on the patients' ability to perform normal activities (i.e., KPS score < 80 or ≥ 80), the predictive accuracy was 57%, and the surgeons underestimated and overestimated in 3% and 40% of cases, respectively. In a binary regression model, the authors found no predictors of underestimation, whereas postoperative complications were an independent predictor of overestimation (p = 0.01). CONCLUSIONS Operating neurosurgeons often overestimate their patients' postoperative functional level, especially when it comes to the ability to perform normal activities at 30 days. This tendency to overestimate surgical outcomes may have implications for clinical decision making and for the accuracy of patient information.

OBJECTIVE Traditionally, the dominant (usually left) cerebral hemisphere is regarded as the more important one, and everyday clinical decisions are influenced by this view. However, reported results on the impact of lesion laterality are inconsistent in the scarce literature on quality of life (QOL) in patients with brain tumors. The authors aimed to study which cerebral hemisphere is the most important to patients with intracranial tumors with respect to health-related QOL (HRQOL). METHODS Two hundred forty-eight patients with unilateral, unifocal gliomas or meningiomas scheduled for primary surgery were included in this prospective cohort study. Generic HRQOL was measured using the EQ-5D-3L questionnaire preoperatively and after 4–6 weeks. Cross-sectional and longitudinal analyses of data were performed. RESULTS Tumor volumes were significantly larger in right-sided tumors at diagnosis, and language or speech problems were more common in left-sided lesions. Otherwise, no differences existed in baseline data. The median EQ-5D-3L index was 0.73 (range −0.24 to 1.00) in patients with right-sided tumors and 0.76 (range −0.48 to 1.00) in patients with left-sided tumors (p = 0.709). Due to the difference in tumor volumes at baseline, histopathology and tumor volumes were matched in 198 patients. EQ-5D-3L index scores in this 1:1 matched analysis were 0.74 (range −0.7 to 1.00) for patients with right-sided and 0.76 (range −0.48 to 1.00) for left-sided lesions (p = 0.342). In the analysis of longitudinal data, no association was found between tumor laterality and postoperative EQ-5D-3L index scores (p = 0.957) or clinically significant change in HRQOL following surgery (p = 0.793). CONCLUSIONS In an overall patient-reported QOL perspective, tumor laterality does not appear to be of significant importance for generic HRQOL in patients with intracranial tumors. This may imply that right-sided cerebral functions are underestimated by clinicians.

Few studies have assessed patient-reported quality of life (QoL) in patients with glioma undergoing surgery, and even fewer have provided longitudinal data. Accordingly, there is little knowledge about the changes of QoL over time in patients with glioma. We sought to explore perioperative and postoperative development of generic QoL during the first 6 months after primary glioma surgery.A total of 136 adult patients undergoing primary surgery for high-grade glioma (HGG) or low-grade glioma (LGG) were prospectively included in this explorative longitudinal study. Patient-reported QoL was measured with the generic tool EQ-5D 3L preoperatively and at 1 and 6 months after surgery.At group level, there was no difference in EQ-5D index values in patients with HGG compared with patients with LGG at baseline or at 1 month. At 6 months, EQ-5D index values in patients with HGG had deteriorated significantly (P0.001) but remained stable in patients with LGG. Individual level QoL development was more diverse. American Society of Anesthesiologists class ≥3, resection grades other than gross total resection, and HGG were identified as independent predictors for negative development of QoL between 1 and 6 months after surgery.At group level, development of generic QoL between baseline and 1 and 6 months postoperatively seems to follow the natural disease trajectories of LGG and HGG, with deterioration in patients with HGG at 6 months. Individual development of QoL is heterogeneous. HGG, resection grades other than gross total resection, and preoperative comorbidity are predictors of postoperative impairment of QoL.

Duration of surgery has not been much explored as a possible risk factor for complications in neurosurgery. To explore the possible impact of duration of surgery on the risk of developing extracranial complications and surgical site infections following intracranial tumor surgery. Retrospective review of 1,000 consecutive patients who underwent planned surgery for intracranial tumors at a single institution. Complications within 30 days of surgery were registered. Of all patients, 18.6 % acquired extracranial complications, and they were seen in 14.3, 17.7, 22.1 and 37.4 % after operations lasting

Accretion discs around black holes can become warped by Lense-Thirring precession if the disc is tilted with respect to the black hole spin vector. When the disc viscosity is sufficiently large that warp propagation is diffusive, the inner disc can align with the black hole spin. However, if the viscosity is small, such that the warp propagates as a wave, then steady-state solutions to the linearised fluid equations exhibit an oscillatory radial profile of the disc tilt angle close to the black hole. Here we show, for the first time, that these solutions are in good agreement with three-dimensional hydrodynamical simulations, in which the viscosity is isotropic and measured to be small compared to the disc angular semi-thickness, and in the case that the disc tilt -- and thus the warp amplitude -- remains small. We show using both the linearised fluid equations and hydrodynamical simulations that the inner disc tilt can be more than several times larger than the original disc tilt, and we provide physical reasoning for this effect. We explore the transition in disc behaviour as the misalignment angle is increased, finding increased dissipation associated with regions of strong warping. For large enough misalignments the disc becomes unstable to disc tearing and breaks into discrete planes. For the simulations we present here, we show that the total (physical and numerical) viscosity at the time the disc breaks is small enough that the disc tearing occurs in the wave-like regime, substantiating that disc tearing is possible in this region of parameter space. Our simulations demonstrate that high spatial resolution, and thus low numerical viscosity, is required to accurately model the warp dynamics in this regime. Finally, we discuss the observational implications of our results., 19 pages, 9 figures, accepted for publication in The Astrophysical Journal