Diagnosis and Management of Dural Sinus Thrombosis following Resection of Cerebellopontine Angle Tumors

Objective Lateral sinus thrombosis is a potentially devastating but seldom studied complication of cerebellopontine angle (CPA) tumor surgery. Systemic anticoagulation in the early postoperative period has often been avoided due to the potential risks of intracranial hemorrhage. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures The goal of this study was to identify the frequency, treatment, and outcomes in patients who develop postoperative venous sinus thrombosis following CPA tumor surgery and receive early systemic anticoagulation. Results Of 43 patients with CPA tumors, we report five patients (11.6%) with transverse and/or sigmoid sinus thrombosis following resection of the tumor, four of which were detected on routine early postoperative noncontrast computed tomography (CT) scan. The thrombosis was confirmed in all cases with CT venography or magnetic resonance venography. Affected patients had significantly larger tumors than controls and tended to undergo longer operations. These patients were treated with immediate anticoagulation (intravenous heparin, followed by Coumadin for 6 months) without complication. Conclusion Venous sinus thrombosis is an underrecognized complication of CPA surgery, but it can be diagnosed in the early postoperative period by noncontrast CT imaging. Early postoperative initiation of systemic anticoagulation appears safe and effective to prevent the progression of thrombosis and its consequences.     

How superhydrophobicity breaks down

A droplet deposited or impacting on a superhydrophobic surface rolls off easily, leaving the surface dry and clean. This remarkable property is due to a surface structure that favors the entrainment of air cushions beneath the drop, leading to the so-called Cassie state. The Cassie state competes with the Wenzel (impaled) state, in which the liquid fully wets the substrate. To use superhydrophobicity, impalement of the drop into the surface structure needs to be prevented. To understand the underlying processes, we image the impalement dynamics in three dimensions by confocal microscopy. While the drop evaporates from a pillar array, its rim recedes via stepwise depinning from the edge of the pillars. Before depinning, finger-like necks form due to adhesion of the drop at the pillar’s circumference. Once the pressure becomes too high, or the drop too small, the drop slowly impales the texture. The thickness of the air cushion decreases gradually. As soon as the water–air interface touches the substrate, complete wetting proceeds within milliseconds. This visualization of the impalement dynamics will facilitate the development and characterization of superhydrophobic surfaces.     

Far lateral paracondylar versus transcondylar approach in the pediatric age group: CT morphometric analysis

This study aimed to determine if partial removal of the occipital condyle provides a significant increase in visibility and “angle of attack” for treating lesions with extension ventral to the brainstem in children using CT morphometric data. Morphometric analysis was performed in 199 children using CT scans. Angle of attack was measured for both the paracondylar and transcondylar far lateral approach. Statistical analysis was performed using paired or unpaired Student’s t-tests (p < 0.05) and linear regression analysis. For the far lateral paracondylar approach, the overall angle of attack was 85 ± 9 degrees (range, 60–119 degrees). The overall angle of attack for the far lateral transcondylar approach was 70 ± 9 degrees (range, 48–105 degrees). This difference was significant (p < 0.0001). Based on our data, resection of one-third of the occipital condyle in a far lateral transcondylar approach can improve angle of attack by approximately 15 degrees, regardless of age or sex, in the pediatric age group. It is important to keep in mind that there are risks attendant to resection of the occipital condyle, thus the resection of the occipital condyle in children should not be a mandatory part of the far lateral approach; rather, the decision-making should be individualized and considered on a case-by-case basis.     

Validity and reliability of wheelchair sitting posture measures using Coach’s Eye in abled subjects

People in wheelchairs spend a long time in the sitting position and often incur alignment problems resulting in neck and back pain. This study: (1) assessed the validity/reliability of Coach’s Eye (CE) smart device application, (2) examined the effect of seat to back support angle adjustments on head, neck, and shoulder posture in the sitting position, and (3) compared changes in cervical rotation at each back support angle. Abled subjects sat in a wheelchair with back support angles positioned at 90°, 100°, and 110°. CE, as well as ImageJ software, was used to analyze three angles: sagittal head angle (SHA), cervical angle (CVA), and shoulder angle (SA). There were highly significant differences for CVA and SA (p < 0.001) among the three seat to back support angles. Validity of CE was examined by correlating CE with ImageJ scores. CE had high validity for all angles (r = 0.99, 0.98, 0.99 respectively, p < 0.001). Inter-rater reliability for SHA, CVA, and SA was high (intraclass correlation coefficient [ICC] ranged from 0.95 to 0.99). Head (CVA) and shoulder (SA) alignment was closest to neutral posture with back support angles set at 110° and 90°, respectively.     

Characteristics and reproducibility of anterior chamber angle assessment by anterior‐segment optical coherence tomography

Purpose: To evaluate the basic characteristics and reproducibility of anterior chamber angle (ACA) measurements determined by anterior‐segment optical coherence tomography (AS‐OCT) in open‐angle and primary angle closure suspect (PACS) patients. Methods: Thirty‐nine open‐angle and 18 PACS patients were imaged for ACA by AS‐OCT. Subjects underwent imaging of the nasal, temporal and inferior ACA under conditions of constant light, and darkness. For analysis, we used three ACA parameters handled by the Visante OCT software: angle opening distance at 500 μm (AOD₅₀₀), trabecular‐iris space area at 500 μm (TISA₅₀₀) and angle recess area at 500 μm (ARA₅₀₀). For determination of inter‐session reproducibility, a single well‐trained operator (D.Y.K.) scanned all patients at two different visits. For determination of inter‐operator variability, a second operator (S.B.P.) acquired another set of images independently. Three sets of images were acquired at least 24 hour apart. Results: All parameters were significantly different when measured both in light and darkness, and in the nasal and temporal quadrants. There were no significant differences between the left and right eyes in the three ACA parameters in all quadrants. The temporal angle was wider than the nasal and inferior angles. All parameters of the nasal, temporal angles had excellent inter‐session and inter‐operator reproducibility [intra‐class correlation coefficient (ICC) 0.796–0.981], but these values were slightly lower for inferior angle measurements (ICC 0.662–0.892) in both open‐angle and PACS groups. Conclusion: AS‐OCT provides quantitative and reproducible assessment of ACA. Reproducibility was lower in the inferior angle compared with the nasal and temporal angles, perhaps because of variable placement of the scleral spur.     

Dipole tensor-based atomic-resolution structure determination of a nanocrystalline protein by solid-state NMR

Magic-angle spinning (MAS) solid-state NMR (SSNMR) techniques have emerged in recent years for solving complete structures of uniformly labeled proteins lacking macroscopic order. Strategies used thus far have relied primarily on semiquantitative distance restraints, analogous to the nuclear Overhauser effect (NOE) routinely used in solution NMR. Here, we present a complementary approach for using relative orientations of molecular fragments, determined from dipolar line shapes. Whereas SSNMR distance restraints typically have an uncertainty of approximately 1 A, the tensor-based experiments report on relative vector (pseudobond) angles with precision of a few degrees. By using 3D techniques of this type, vector angle (VEAN) restraints were determined for the majority of the 56-residue B1 immunoglobulin binding domain of protein G [protein GB1 (a total of 47 HN-HN, 49 HN-HC, and 12 HA-HB restraints)]. By using distance restraints alone in the structure calculations, the overall backbone root-mean-square deviation (bbRMSD) was 1.01 +/- 0.13 A (1.52 +/- 0.12 A for all heavy atoms), which improved to 0.49 +/- 0.05 A (1.19 +/- 0.07 A) on the addition of empirical chemical shift [torsion angle likelihood obtained from shift and sequence similarity (TALOS)] restraints. VEAN restraints further improved the ensemble to 0.31 +/- 0.06 A bbRMSD (1.06 +/- 0.07 A); relative to the structure with distances alone, most of the improvement remained (bbRMSD 0.64 +/- 0.09 A; 1.29 +/- 0.07 A) when TALOS restraints were removed before refinement. These results represent significant progress toward atomic-resolution protein structure determination by SSNMR, capabilities that can be applied to a large range of membrane proteins and fibrils, which are often not amenable to solution NMR or x-ray crystallography.     

可调式CT扫描多功能头托的设计

结合实际工作及临床经验,设计了一款可调式CT扫描多功能头托。该头托集角度调整及显示装置、头托升降装置及自锁装置为一体,具有一托多用、方便快捷的优点,可解决头颅CT扫描过程中需不断换用不同头托及调整扫描机架角度等繁琐的操作问题,进而在保证良好CT图像质量的前提下节省扫描时间。