后路枕骨髁螺钉技术研究进展

正枕骨、寰椎和枢椎共同构成了枕颈部活动的结构功能单位,即枕颈交界区~([1-2])。炎症、创伤、肿瘤及畸形等因素会导致枕颈交界区失稳,从而引起颈脊髓或神经根的损伤、麻痹及难以忍受的疼痛,甚至危及生命~([3-4])。后路内固定融合技术是治疗枕颈部失稳的重要手段,目前常用术式为枕骨螺钉技术,该技术较钢丝固定技术有更好的生物力学稳定     

Image technique optimization in MR imaging of a titanium alloy joint prosthesis

The purpose of this study was to explore systematically the effect of the imaging parameters changeable by the user in spin-echo (SE) imaging sequences to minimize image distortion when imaging joint prostheses. A titanium alloy hip joint prosthesis was studied at 1.0 T. The SE imaging parameters were bandwidth/pixel (BW/p), TE, strength of encoding gradients (matrix size), echo train length (ETL), and direction of phase and frequency encoding. The effect of ETL in rapid acquisition relaxation enhanced (RARE) sequences was also evaluated with a turbo-SE sequence using a different ETL with the same TR and an effective TE. It is concluded that an optimized image quality can be achieved in SE imaging by using a high bandwidth/pixel value (at least 130 Hz/pixel), a high resolution matrix (256–512), sequences with multiple refocusing, and a frequency-encoding axis parallel to the long axis of the prosthesis. The degree of distortion is reduced with this optimized technique.     

门脉高压性胃病患者的胃壁血气变化

作者观测了４３例门脉高压症患者股动脉血ＰＯ２、胃网膜有动静脉胃壁支血ＰＯ２、胃壁支静脉及肘静脉血ｐＨ、ＨＣＯ３－和胃网膜右静脉压力，其中２３例并有非出血期门脉高压性胃病。结果表明：①门脉高压症患者的股动脉血ＰＯ２低于对照组；②门脉高压症患者胃网膜右动静脉胃壁支血氧分压差低于对照组，胃网膜右静脉压力高于对照组，胃壁支静脉血ｐＨ和ＨＣＯ３－低于对照组和同组肘静脉血。并有门脉高压性胃病者这些变化更为显著。提示门脉高压性胃病的发病机制在于门脉系压力增高、胃粘膜下动静脉短路开放、胃粘膜缺血缺氧和胃壁局部酸中毒。     

Social and psychological factors associated with adolescents'' self-acceptance of occlusal condition

Studies using plaster models of teeth and photographs simulating the full range of occlusal conditions have found high agreement between measures of adolescent social acceptability of these conditions and perceived need for orthodontic treatment. This study examined the association between adolescents' acceptability of their own occlusal condition, severity of malocclusion, and likelihood of undergoing orthodontic treatment. The factors predicting the acceptability of occlusal condition of 13-yr-olds, as assessed by the SASOC scale, were measurements of acceptability of general physical appearance, and the severity of occlusal condition. Variability in SASOC scores appeared to be independent of gender, socioeconomic status, and ethnicity. Gender, and severity of occlusal condition were important differences between subjects who had received, planned, or were undergoing orthodontic treatment, and those who had not. Neither SASOC scores nor perceived need for treatment accounted for a significant proportion of the variance between these groups. Although adolescents seeking orthodontic treatment had a greater severity of malocclusion than those not, little difference was observed between these groups in acceptance of occlusal condition.     

螺旋CT多功能重建在骨关节外伤中的应用

目的 探讨螺旋cT功能重建在骨与关节外伤中的应用，提高重建技术的使用能力和诊断水平。方法 对使用双层螺旋CT，SSD，MPR，MIP等多种方式重建检查的49例复杂的骨与关节外伤病例进行回顾性分析。结果 49例骨关节外伤重建成像，其中，颅底3例，颌面部7例，颈、胸、腰、骶椎共17例，肩胛骨3例，髋关节8例，膝关节11例。SSD在显示碎骨片明显移位的空间关系方面较MIP，MPR为佳，它可以直观地、立体地、清晰地、多角度显示骨关节损伤，而MIP在显示骨折细节方面较优，尤其在外伤中颅窝观察有关神经孔方面。结论 螺旋CT的SSD，MPR和MIP技术的综合应用，对复杂的骨折、关节损伤的显示效果良好，具有较高的临床应用价值。     

Measurement of upper extremity orientation by video stereometry system

In the attempt to gain a broader understanding of the causal relationships behind work-related symptoms of pain in the human shoulder, monitoring of arm position is crucial. Different methods have been used with varying accuracy. A video-based stereometry system, using infra-red light and reflecting markers for motion analysis, has been introduced for measurements in the fields of ergonomics, biomechanics and sports medicine. The purpose of this study is to investigate the sources of error in using this system for posture registration of the upper limb. Measurements are performed on a calibration fixture, on a mechanical model of the upper limb and on a subject with an exoskeleton. Particular, attention is given to inconsistencies and relative errors due to the finite geometrical precision with which the markers are positioned in the calibration fixture and on the studied objects, the limited capability to align the objects relative to the coordinate system of the calibration fixture and the errors connected to angular measurements using protractors etc. It is concluded that the system makes a valuable addition to existing instruments for non-contact posture measurement, and produces position data with an adequate accuracy in normal handling.     

Recurrent locking of knee joint caused by intraarticular migration of bioabsorbable tibial interference screw after arthroscopic ACL reconstruction

Two cases are reported in which, after ACL reconstruction with autologous hamstring grafts, tibial polylactide interference screws migrated into the knee joint. Clinically, both patients presented with recurrent locking of the joint. In one case, a broken 15 mm-long tip of the screw was found intra-articularly. In the other case, the whole screw had migrated into the joint cavity. The degradation process of polylactic acid, operative technique and bone quality are discussed as possible reasons for these complications.     

YAG激光器谐振腔光振状态的调整

本文介绍了调整谐振腔光振状态的方法和要点，它包括调整谐振腔体和其它的光学部件。本法可应用于YAG激光器谐振腔的维修拆卸重装工作中。     

Dislocation of the second through fifth carpometacarpal joints

We report a case of dislocation of the second through fifth carpometacarpal joints and review the mechanism of injury and radiographic findings in such injuries.