Compartment Syndrome of the Arm After Cable-Wakeboard Accident

Abstract   A compartment syndrome is an increased tissue pressure within a closed osteofascial compartment. This compromises blood flow to the muscles and nerves within that compartment, which –if not treated adequately in an early stage-results in permanent tissue and nerve damage. It most frequently occurs in the lower leg, but can also occur elsewhere when muscles are enclosed in tight fascial compartments, such as the forearm and hand. In this report a patient is described who developed an acute compartment syndrome of the arm after a cable-wakeboard accident in which his arm was strangulated. Cable-wakeboarding is an extreme sport that has become very popular over the last years. Early recognition and treatment of an acute compartment syndrome is of extreme importance since in short term necrotic muscles can lead to severe irreversible complications. Accidents with cable-wakeboarding often occur during the start. This is caused by the strong forces that are on the cable during the start. Strangulation injuries of the arm can cause a compartment syndrome of the arm. Possibly a wet-suit or dry-suit offers some protection. However, the duration of strangulation determines much of the damage. Although diagnosis of a compartment syndrome can be difficult, a high index of suspicion combined with fast and adequate treatment with a fasciotomy improve outcome and prognosis.     

高压电缆隧道移动巡检无线网络软切换技术研究

在城市的电力建设及电力供应中,高压电缆隧道逐步成为城市供电的主要通道,装有双视系统及各种传感器的移动巡检机器人对高压电缆隧道进行巡检将会逐步替代人工巡检。在隧道内安装多个无线AP,移动巡检机器人和无线AP自动连接。论文研究一种软切换技术,确保机器人在运行过程中数据和视频信息能够连续传输。     

Tubular system excitability: an essential component of excitation–contraction coupling in fast-twitch fibres of vertebrate skeletal muscle

The tubular (t-) system is the main interface between the myoplasm and the extracellular environment and is responsible for the rapid inward spread of excitation from the sarcolemma to the inner parts of the skeletal muscle fibre as well as for signal transfer to the sarcoplasmic reticulum to release Ca²⁺ that, in turn, activates the contractile apparatus. In this review, I explore the insights provided by the mechanically skinned muscle fibre preparation to the better understanding of the importance of the t-system excitability in determining the force response under physiologically relevant conditions. In the mechanically skinned muscle fibre, the t-system seals off after is physically separated from the sarcolemma and its excitability can be investigated by electrical stimulation under controlled conditions. Parameters that can be assessed include the threshold for action potential generation, specific electrical resistance and time constant of the tubular wall, quantity of charge transferred during an action potential, refractory period, length constant and velocity of excitation propagation. Results obtained with mechanically skinned fibres from fast-twitch muscles show that decreased t-system excitability does not necessarily translate into reduced force output, but for any particular set of physiologically relevant conditions there is a level below which a further decrease in t-system excitability markedly decreases the force output. There are several built-in mechanisms linked to the metabolic/energetic state of the muscle fibre which prevent complete action potential failure in the t-system, thus allowing the muscle to respond to nerve stimulation, even if the response becomes markedly attenuated.     

Current Evaluation of Hydraulics to Replace the Cable Force Transmission System for Body-Powered Upper-Limb Prostheses

Present body-powered upper-limb prostheses use a cable control system employing World War II aircraft technology to transmit force from the body to the prosthesis for operation. The cable and associated hardware are located outside the prosthesis. Because individuals with arm amputations want prostheses that are natural looking with a smooth, soft outer surface, a design and development project was undertaken to replace the cable system with hydraulics located inside the prosthesis. Three different hydraulic transmission systems were built for evaluation, and other possibilities were explored. Results indicate that a hydraulic force transmission system remains an unmet challenge as a practical replacement for the cable system. The author was unable to develop a hydraulic system that meets the necessary dynamic requirements and is acceptable in size and appearance.     

Passive properties of neostriatal neurons during potassium conductance blockade

Voltage recordings from neostriatal projection neurons were obtained using in vitro intracellular techniques before and during K⁺-conductance blockade. Neurons were stained with the biocytin technique. Somatic surface area (A _S) was determined by both whole-cell recordings in isolated somata and by measuring stained somata recorded in slices. Dendritic measurements were done in reconstructed neurons. Average determinations of dendritic (A _D) and neuronal (A _N) surface areas coincided with previously reported anatomical data. Thus: A _S≈ 6.5 × 10^–6 cm²; A _D≈ 1.9 × 10^–4 cm²; A _N≈A _D + A _S≈ 2 × 10^–4 cm²; A _D/A _S≈ 30. Measurements were done before and after superfusion with K⁺-conductance blockers (K⁺-blockers). Cells whose neuronal morphology was not obviously distorted by K⁺-blockade were chosen for the present study. Electrotonic transients were matched to a somatic shunt equivalent cylinder model adjusted with the generalized correction factor (F _dga) that constrains the parameters for neuronal anatomy. Neuronal input resistance (R _N; mean ± SEM) increased when it was corrected for somatic shunt, from 49 ± 2 MΩ (n = 80) to 179 ± 7 MΩ (n = 32). A difference was also obtained between the slowest time constant, τ₀ = 16 ± 0.9 ms (n = 49), and the dendritic membrane time constant, τ_mD = 33 ± 1.6 ms (n = 36). When these electrophysiological measurements were used to calculate A _N, the value obtained was similar to the anatomical measurements. Combining anatomical and electrophysiological data, somatic and dendritic input resistances were determined: R _D = 182 ± 7 MΩ; R _S (with shunt) = 74 ± 4 MΩ (n = 32). The generalized correction factor, F _dga = 0.91 ± 0.007 (n = 10), implied a short effective electrotonic length for dendrites: L _D = 0.46 ± 0.014 (n = 32). Saturating concentrations of the K⁺-blockers tetraethylammonium, Cs⁺, and Ba²⁺ increased R _N and induced charging curves well fitted by single exponential functions in 56% of neostriatal neurons. Ba²⁺ greatly decreased the somatic shunt (n = 5): (R _N = 216 ± 21 MΩ, τ₀ = 46 ± 2 ms, R _D = 239 ± 25 MΩ, and R _S = 3.2 ± 0.5 GΩ), rendering values similar to those obtained with whole-cell recordings (e.g., R _N≈ 198 MΩ, R_S≈ 2.62 GΩ) (n = 52). Cs⁺ (n = 5) had less effect on the somatic shunt (R _N = 115 ± 19 MΩ, τ₀ = 49 ± 13 ms, R _S = 161 ± 8 MΩ), although dendritic conductance was equally blocked (R _D = 261 ± 16 MΩ). The Cs⁺-sensitive conductance exhibited inward rectifying properties not displayed by the Ba²⁺-sensitive conductance, suggesting that Cs⁺ preferentially acted upon inward rectifier conductances. In contrast, Ba²⁺ significantly acted upon linear conductances making up the somatic shunt. This suggests a differential action of different K⁺-blockers on the somato-dendritic membrane, implying a differential distribution of membrane conductances. Another action of K⁺-blockers, in about 40% of the cells, was to induce dye and probably electrical coupling between neighboring neurons. Received: 30 April 1997 / Accepted: 14 October 1997     

线缆套绕喙突与锁骨固定治疗肩锁关节脱位的临床观察

目的：观察线缆套绕喙突与锁骨固定治疗新鲜单侧TossyⅢ型肩锁关节脱位的临床效果。方法回顾分析2007年12月至2016年3月于我院采用切开复位、线缆套绕喙突与锁骨固定治疗新鲜单侧TossyⅢ型肩锁关节脱位的39例病人的临床资料,通过其术后X线片评价其恢复情况,采用Karlsson疗效评价标准对患肩功能进行评定。结果本组病人随访时间为6~60个月,平均为16个月。术后肩关节外观及功能恢复满意,未见线缆断裂和松动的现象。按照Karlsson疗效评价标准对肩关节功能进行评定,其中优30例,良9例,优良率为100%。结论线缆套绕固定喙突与锁骨符合肩锁关节复位固定的生物力学要求,具有疗效好、创伤小、操作简单的优点,是治疗TossyⅢ型肩锁关节脱位的一种有效手术方法。     

Outcome of alternative approach to displaced acetabular fractures

IntroductionAnatomical reduction of displaced acetabular fracture is not without its’ limitations and complications. This study is conducted to assess clinical and radiological outcomes as well as complications of treating displaced acetabular fractures with emphasis on anatomical reduction in weight-bearing area, mainly the posterior column, and imperfect reduction of the anterior column is acceptable. However, stability of both columns is mandatory.MethodsIt was a retrospective study carried out in a Level 1 arthroplasty and trauma centre. 23 patients (17 males, 6 females) with average age of 50.1 years (range, 36–68 years) with displaced acetabular fracture treated with combined incisions and plate-cable systems were included. There were 3 elementary and 18 associated fractures according to Letournel classification. Average follow-up was 23.5 months (range, 12–38.7 months). Mean operation time was 160 min (range: 75–320 min). Functional scores were evaluated using Harris Hip Score (HHS) whilst reduction was assessed by Matta criteria. Any displacement of reduction, osteoarthritis, heterotopic ossification, and other complications was recorded.Result65.2% (15/23) of the patients obtained excellent HHS and 21.7% (5/23) had good HHS. There were 12 anatomical, 6 imperfect, and 5 poor reductions. No displacement was recorded in final follow-up. Complications documented: three lateral femoral cutaneous nerve injuries, two conversions to total hip arthroplasty, three Brooker stage 1 heterotrophic ossification, one pulmonary embolism and one screw irritation. No incidence of wound breakdown, infection and radiological osteoarthritis was reported.ConclusionsImperfect reduction of the anterior column provided clinical outcomes that are as good as total anatomical reduction. This approach minimizes soft tissue damage and reduces perioperative morbidities.     

医院有线电视系统的构建设计

目的利用医院有线电视台传播医院文化和优势技术。方法以自制节目和非自制节目形式,通过总体设计、需求分析、节目设置和视频采编技术构建医院有线电视系统。结果该系统是传播医院文化、提升医院形象、展示优势技术的有效平台。结论实现"低成本,高质量"构建医院有线电视系统的总体设计可行,将创造可观的经济效益和广泛的社会效益。     

钢缆环扎加改良张力带治疗粉碎性髌骨骨折

目的 探讨钢缆(cable)环扎加改良张力带治疗粉碎性髌骨骨折的疗效.方法 回顾性分析120例粉碎性髌骨骨折患者应用钢缆环扎加改良张力带内固定(cable组,55例)与镍钛合金-聚髌器(NT-PC)内固定(NT-PC组,65例)的临床疗效.结果 所有病例随访10～38(19.50±1.15)个月,骨折均于12周内愈合.两组手术时间、术中出血量、住院时间、骨折愈合时间、术后并发症比较差异无统计学意义(P＞0.05).术后cable组B(o)stman评分(27.0±0.2)分,明显优于NT-PC组的(25.1±0.6)分(P＜0.05).结论 应用钢缆环扎加改良张力带治疗粉碎性髌骨骨折操作方便,疗效优良.     

横向电场作用下外周神经的兴奋模型

外周神经的兴奋机理研究是以神经生理学的电缆方程为基础,方程中的激励因子只与外电场沿神经方向的纵向电场分量有关。但实验表明垂直于神经走向的横向电场也可以兴奋外周神经,因而传统电缆方程不能客观反映外周神经兴奋实际过程而需要改进。本文基于两阶段过程,建立了横向电场作用下外周神经的兴奋模型,表明了在横向电场作用下沿朗飞氏结径向的净内向电流导致了神经兴奋,从而阐述了外周神经在横向电场中的兴奋机理,改进了经典电缆方程。模型通过了离体实验验证。此改进的电缆方程可以描述任意电场激励下的外周神经兴奋。