Using EMG to evaluate muscle functions in patients with low back pain (LBP) syndromes

Muscle function is relevant to the effective diagnosis and treatment of LBP, although the qualitative and quantitative measurement of muscle function remains problematic. The aims of this study is to evaluate the spinal musculature function and contraction profiles for patients with low back pain (LBP) syndromes both pre and post treatment, and to compare these results to those obtained from normal subjects. 20 normal subjects and 10 patients with LBP were asked to perform symmetrical and asymmetrical loading activities which simulated common industrial tasks. Surface EMG electrodes and video cameras were used to record muscular activity and spinal kinematics. In comparison with the normal group, subjects with LBP showed different muscle activations profiles. No change in the EMG patterns was seen pre and post-treatment.published_or_final_versionThe 20th IEEE Engineering in Medicine and Biology Society Conference Proceedings, Hong Kong, China, 29 October - 1 November 1998, v. 5, p. 2666-266

NEW INTERPRETATION ON EMG CHARATERISTICS OF SPASTIC CEREBRAL PALSY DURING A REHABILITATIVE WALKING EXERCISE

The purpose of this study is to interpret the EMG characteristics of spastic cerebral palsy children during walking with power spectrum analysis. The EMG signal of 16 cerebral palsy patients (GP) and 18 age matched control (Normal) were collected during several walking trial. It was found that our CP participants ha:d significantly longer firing duration and higher median frequency within a gait cycle for al.l the muscle groups, these indicated of the EMG characteristics of in the spastic muscles. In addition, the CP produced significantly smaller root mean square value in tibialis anterior muscle than the normal; this indicated that the tibialis anterior muscle of GP was weakness or atrophy. Because of good objectivity and reproducibility, employing RMS and the MF could :be suggested to be the parameters for further gait studies

Modeling of the current density distribution under surface posterior-tibial-nerve electric stimulator

Stimulation of the posterior tibial nerve is commonly used in the measurement of somatosensory evoked potential (SEP). To improve the efficiency of stimulation, the potential field and current density distributions under the surface electrodes were modeled and simulated. In our model, three layers were assumed: (1) the air environment, (2) electrode and paste (3) human body (skin and soft tissues). The mirror method was used to analyze the potential field of point charge. Integration of the field and the area of the stimulus gave the potential field of one surface electric pole. The potential field distribution of the bipolar stimulator was obtained by superimposition of two unipolar fields. Finally, the current density distribution was calculated by Laplace equation. The analytical solution of the potential field was found and the numerical solution of the current density distribution calculated. The potential field and current density distributions were simulated by 2-D plot. From the model and simulation, the potential and current density distributions were not found to be uniform under transcutaneous stimulation electrode and the maximum current density is located under the poles. We recommend that bipolar stimulator should be applied axially along the stimulated nerve course.published_or_final_versio

骶骨螺釘四種固定方式的生物力學分析

Objective To evaluate the effects of fatigue loading on the pull out strength of medial and lateral unicortical and bicortical sacral screws Methods Eleven fresh specimens of human sacrum were used in this study Bone mineral density (BMD) at the vertebral body and the ala were determined by peripheral quantitative computed tomography Seven millimeter compact CD sacral screws were inserted into the sacrum anteriomedially,anteriolaterally, unicortically and bicortically,and the insertion torque for each screw was measured Cyclic loading from 40 N to 400 N was applied to each screw at a frequency of 2 Hz up to 20 000 cycles Pull out tests were conducted after completion of the fatigue tests Results The average bone density at the S 1 body was 0 38 g/ml, and 0 24 g/ml at the S 1 ala The insertion torque and average pull out force following cyclic loading were significantly higher in bicortical fixation than that in unicortical fixation However, the pull out strength and insertion torque of medially oriented fixation was always higher than lateral fixation, regardless of whether the insertion was unicortical or bicortical The pull out force of unicortical and bicortical medial screw fixations following cyclic loading showed significant linear correlations with both the insertional torque and the bone mineral density of the S 1 body Conclusion In a group of young population, screw orientation(anterolateral or anteromedial) is more important in determining pull out strength than screw depth(unicortical or bicortical) following fatigue loading, anteromedially directed screws being significantly stronger than laterally placed screws Bone mineral density of the S 1 body and insertion torque are good preoperative and intraoperative indicators of screw pull out strength 目的 研究骶骨螺釘固定在承受周期性載荷后的拔出強度,評價前內、前外側和單、雙邊皮質螺釘固定的生物力學作用。方法 對11 具新鮮成人尸體的骶骨行定量CT(QCT)掃描以確定S1 椎體和骶骨翼的骨礦物質密度。CCD骶骨螺釘分別放置在骶骨的前內、前外側和單、雙邊皮質等四個位置上,測量螺釘固定時旋入的力矩。對螺釘施加40～400 N 的垂直周期性載荷,載荷頻率為2Hz,加載次數為20 000 次。然后行螺釘拔出試驗,獲得螺釘最大拔出力。結果 S1 椎體和骶骨翼的平均骨礦物質密度分別為0-38 g/ml 和0-24g/ml。雙邊皮質螺釘固定時的旋入力矩和最大拔出力均顯著大于單邊皮質螺釘。而無論是單邊或雙邊皮質固定, 內側螺釘固定的旋入力矩和最大拔出力都顯著高于外側螺釘。內側螺釘固定的最大拔出力與S1 椎體的骨礦物質密度和旋入力矩呈線性相關。結論對于年輕人群, 骶骨螺釘固定的方向對螺釘固定的最大拔出力的影響比螺釘插入深度的影響要大,前內側螺釘固定要明顯強于前外側螺釘固定。S1 椎體骨礦物質密度和螺釘旋入力矩可分別反映螺釘在術前和術中的固定強

Chinese herbal medicine for symptom management in cancer palliative care systematic review and meta-analysis

© 2016 Wolters Kluwer Health, Inc. All rights reserved. Use of Chinese herbal medicines (CHM) in symptom management for cancer palliative care is very common in Chinese populations but clinical evidence on their effectiveness is yet to be synthesized. To conduct a systematic review with meta-analysis to summarize results from CHM randomized controlled trials (RCTs) focusing on symptoms that are undertreated in conventional cancer palliative care. Five international and 3 Chinese databases were searched. RCTs evaluating CHM, either in combination with conventional treatments or used alone, in managing cancer-related symptoms were considered eligible. Effectiveness was quantified by using weighted mean difference (WMD) using random effect model meta-analysis. Fourteen RCTs were included. Compared with conventional intervention alone, meta-analysis showed that combined CHM and conventional treatment significantly reduced pain (3 studies, pooled WMD:-0.90, 95% CI:-1.69 to-0.11). Six trials comparing CHM with conventional medications demonstrated similar effect in reducing constipation. One RCT showed significant positive effect of CHM plus chemotherapy for managing fatigue, but not in the remaining 3 RCTs. The additional use of CHM to chemotherapy does not improve anorexia when compared to chemotherapy alone, but the result was concluded from 2 small trials only. Adverse events were infrequent and mild. CHM may be considered as an add-on to conventional care in the management of pain in cancer patients. CHM could also be considered as an alternative to conventional care for reducing constipation. Evidence on the use of CHM for treating anorexia and fatigue in cancer patients is uncertain, warranting further research