Comparative analysis of safety and efficacy in subperiosteal versus subdural drainage after burr-hole trephination for chronic subdural hematoma.

PURPOSE: The treatment of choice for chronic subdural hematoma (CSDH) has been established as burr-hole trephination with drain insertion; however, controversy remains over the best place for the drainage catheter. In this study, we compare the safety and efficacy of a subperiosteal drain (SPD) with that of a subdural drain (SDD) after one burr-hole trephination for CSDH. METHODS: This retrospective and comparative study includes all CSDH patients treated with burr-hole trephination at our institution between January 2015 and December 2019. 59 patients were treated with SPD insertion (SPD group), and 203 patients were treated with SDD insertion (SDD group). RESULTS: The median hematoma thickness of the SPD group within 24 h after surgery was significantly thicker than that of the SDD group (9.5 mm vs. 7.5 mm, p = 0.003), but the midline shifting of the SPD group did not differ from that of the SDD group (3.8 mm vs. 3.5 mm, p = 0.280). The recurrence rate in the SPD group did not differ significantly from that in the SDD group (13.2% vs. 8.5%, p = 0.351). The frequency of bleeding events after surgery also did not differ significantly (5.1% vs. 3.5% p-value = 0.636). In contrast to surgery-related morbidities, medical morbidities such as pneumonia were significantly higher in the SDD group (4.4% vs. 0.0%, p = 0.044). The all-cause mortality rates during the perioperative period did not differ between the two groups (5.1% vs. 3.4%, p = 0.848). CONCLUSION: Our findings may suggest that burr-hole trephination with SPD insertion had better surgical feasibility and fewer perioperative complications than SDD insertion. The type of anesthesia seems to be related with fewer medical complications at perioperative period. Larger, randomized clinical trials focusing not only the drain type but anesthesia type, are needed to validate our findings.

HLA polymorphisms and risk of glioblastoma in Koreans.

PURPOSE: Immune responses for cancer cells can be altered according to genetic variation of human leukocyte antigen (HLA). Association of HLA polymorphism with risk of various cancer types is well known. However, the association between HLA and glioblastoma (GBM) remains uncertain. We sought to evaluate the association of HLA polymorphism with risk of GBM development in Koreans. MATERIALS AND METHODS: A case-control study was performed to identify the odds ratios (OR) of HLA class I and II genes for GBM. The control group consisted of 142 healthy Korean volunteers, and the GBM group was 80 patients with newly diagnosed GBM at our institution. HLA class I (-A, -B, and-C) and class II (-DR, -DQ, and-DP) genotyping was performed by high-resolution polymerase chain reaction (PCR)-sequence-based typing (PCR-SBT) methods. RESULTS: There were significantly decreased frequencies of HLA-A*26:02 (OR 0.22 CI 0.05-0.98), HLA-C*08:01 (OR 0.29 CI 0.10-0.87), and HLA-DRB1*08:03 (OR 0.32 CI 0.11-0.98), while there was significantly increased frequency of HLA-C*04:01 (OR 2.29 CI 1.05-4.97). In analysis of haplotypes, the frequency of DRB1*14:05-DQB1*05:03 was significantly decreased (OR 0.22 CI 0.05-0.98). CONCLUSION: This study suggests that genetic variations of HLA may affect GBM development in Koreans. Further investigations with larger sample sizes are needed to delineate any potential role of the HLA polymorphisms in the pathogenesis of GBM development.

Effect of partial coherence on dimensional measurement sensitivity for DUV scatterfield imaging microscopy.

Optical scatterfield imaging microscopy technique which has the capability of controlling scattered fields in the imaging mode is useful for quantitative nanoscale dimensional metrology that yields precise characterization of nanoscale features for semiconductor device manufacturing process control. To increase the sensitivity in the metrology using this method, it is required to optimize illumination and collection optics that enhance scatterfield signals from the nanoscale targets. Partial coherence of the optical imaging system is used not only for enhancing image quality in the traditional microscopy or lithography but also for increasing the sensitivity of the scatterfield imaging microscopy. This paper presents an empirical investigation of the effect of partial coherence on measurement sensitivity using a deep ultraviolet scatterfield imaging microscope platform that uses a 193 nm excimer laser as a source and a conjugate back focal plane as a unit for controlling partial coherence. Dimensional measurement sensitivity is assessed through analyzing scatterfield images measured at the edge area of periodic multiline structures with nominal linewidths ranging 44-80 nm on a Molybdenum Silicide (MoSi) photomask. Intensities scattered from the targets under the illuminations with various partial coherence factors and two orthogonal polarizations are assessed with respect to sensitivity coefficient. The optimization of partial coherence factor for the target dimension is discussed through the sensitivity coefficient maps.

Measurement method for profiling the residual stress of an optical fiber: detailed analysis of off-focusing and beam-deflection effects.

The effects of off-focusing and beam deflection on polarimetric stress measurements of optical fibers are investigated. A simple method for reducing the distortion of the phase retardation caused by unwanted beam deflections in residual stress measurement is introduced. The method is examined numerically by ray-tracing techniques and experimentally by use of hollow silica fibers into which various index-matching liquids have been inserted. An autofocusing technique is introduced. The error in stress measurement reproducibility was determined to be less than 4%. We tested the absolute error in measured stress by applying incremental external tension and determined that it is less than 0.464 MPa.