Effect of repeated freezing–thawing on the Achilles tendon of rabbits

The increased use of allograft tissue in the reconstruction of anterior cruciate ligament has brought more focus to the effect of storage and treatment on allograft. The purpose of this study was to observe the effect of histology and biomechanics on Achilles tendon in rabbits through repeated freezing–thawing before allograft tendon transplantation. Rabbit Achilles tendons were harvested and processed according to the manufacture’s protocol of tissue bank, and freezing–thawing was repeated three times (group 1) and ten times (group 2). Those received only one cycle were used as controls. Then, tendons in each group were selected randomly to make for histological observations and biomechanics test. Histological observation showed that the following changes happened as the number of freezing–thawing increased: the arrangement of tendon bundles and collagen fibrils became disordered until ruptured, cells disrupted and apparent gaps appeared between tendon bundle because the formation of ice crystals. There were significant differences between the experimental and control groups in the values of maximum load, energy of maximum load and maximum stress, whereas no significant differences existed in other values such as stiffness, maximum strain, elastic modulus, and energy density. Therefore, repeated freezing–thawing had histological and biomechanical effect on Achilles tendon in rabbits before allograft tendon transplantation. This indicates that cautions should be taken in the repeated freezing–thawing preparation of allograft tendons in clinical application.     

陈旧性颈髓损伤的外科治疗

目的：观察颈椎减压融合手术对陈旧性颈椎骨折脱位引起的颈脊髓或神经根损伤的治疗效果。方法：1999年1月～2003年12月手术治疗因颈椎骨折脱位合并不同程度颈脊髓损伤后1个月以上的患者58例，总结临床资料，比较手术前后感觉运动功能的改善程度。结果：平均随访27个月。术前ASIA分级A级的7例患者术后上肢有1～2个神经根功能改善者3例，下肢出现肌肉活动功能改善者2例：术前B级的11例患者术后8例上肢活动有改善，6例出现下肢功能改善；术前C级6例患者术后达D级3例，E级3例：术前D级34例患者术后达到E级24例，10例仍为D级。所有患者术后ASIA的感觉及运动评分较术前明显提高（P〈0．05）。结论：减压融合手术对陈旧性颈椎骨折脱位引起的颈脊髓损伤或神经根损伤仍是有效的治疗方法，脊髓功能的恢复与脊髓损伤程度有关。     

术前MRI测量脊髓受压程度与脊髓型颈椎病手术疗效的相关性

【摘要】 目的：探讨术前应用MRI测量的脊髓受压程度与脊髓型颈椎病手术效果的相关性。方法：2006年2月~2010年7月在北京大学第三医院骨科行颈前路或后路减压手术的115例脊髓型颈椎病患者被纳入研究,其中男70例,女45例,年龄24~85岁,平均56岁。随访时间24~60个月,平均29个月。在术前MRI矢状位T2像上观察脊髓受压节段数,并在受压最重节段测量并计算硬膜囊中矢径/椎体中矢径（中矢径比值）;在相同节段MRI轴位T2像上测量并计算脊髓矢状径/硬膜囊矢状径×100%（矢状径占有率）、脊髓水平径/硬膜囊水平径×100%（水平径占有率）、脊髓横截面积/硬膜囊横截面积×100%（硬膜囊占有率）。应用改良JOA（mJOA）评分评价患者脊髓功能,应用评分改善率评价手术效果。将患者脊髓受压节段数、中矢径比值、矢状径占有率、水平径占有率、硬膜囊占有率及术前mJOA评分与术后24个月mJOA评分及评分改善率进行相关性分析,并以术后24个月mJOA评分改善率为因变量,以上述各MRI测量指标及术前mJOA评分为自变量,向后线性回归分析,得到拟合mJOA评分及评分改善率,并采用Pearson相关系数检验实际mJOA评分改善率与拟合mJOA评分改善率的相关性。结果：脊髓受压1个节段37例,2个节段17例,3个节段15例,4个节段25例,5个节段21例。MRI中矢径比值为0.426±0.097,矢状径占有率为（79.1±8.4）%,水平径占有率为（76.2±7.3）%,硬膜囊占有率为（54.6±16.2）%。mJOA评分由术前的12.1±2.9分增加至术后的14.7±2.0分（P<0.001）;mJOA评分改善率为（43.0±55.7）%（-200%~100%）。术后24个月mJOA评分及评分改善率与术前mJOA评分、中矢径比值、矢状径占有率均显著相关（P<0.05）,与受压节段数、水平径占有率及硬膜囊占有率无显著相关性（P>0.05）。对术后24个月mJOA评分向后线性回归得到方程：术后24个月mJOA评分=4.202+0.346×术前mJOA评分+4.973×中矢径比值+0.053×矢状径占有率（%）。对mJOA评分改善率向后线性回归得到方程：mJOA评分改善率（%）=-30.348+115.875×中矢径比值+1.226×矢状径占有率（%）-5.993×术前mJOA评分,依据上述回归方程计算的拟合mJOA评分改善率与实际mJOA评分改善率显著相关（R2=0.138,P<0.001）。结论：术前应用MRI测量的脊髓在矢状径方向的受压程度和脊髓型颈椎病的手术效果显著相关。     

Spontaneous Swallowing Frequency,Dysphagia, and Drooling in Children With Cerebral Palsy

ObjectiveTo evaluate relationships between spontaneous swallowing frequency, dysphagia, and drooling in children with cerebral palsy. Spontaneous swallowing frequency was predicted to be inversely related to both dysphagia and drooling among children with cerebral palsy. A secondary objective compared patterns among spontaneous swallowing frequency, drooling, and age in healthy children vs children presenting with cerebral palsy.DesignCross sectional study.SettingChildren with cerebral palsy were tested at a Cerebral Palsy Reference Center in a university hospital. Healthy children were tested in their home setting.ParticipantsTwenty children with cerebral palsy were recruited from the local registry for cerebral palsy children and purposive sampling among parents. A group of 30 healthy children was recruited by purposive sampling among family, friends, and the local community. Children below 1 year of age up to 5 years of age were included in the healthy group. This age range was targeted to maximize the potential for drooling in this group.Main Outcome MeasuresBoth groups provided data on spontaneous swallowing frequency (swallows per minute, or SPM), dysphagia, and drooling. Motor impairment was documented in the children with cerebral palsy.ResultsSPM was significantly lower in children with cerebral palsy. Among children with cerebral palsy, SPM correlated significantly with dysphagia severity and trended toward a significant correlation with drooling at rest. In this subgroup, SPM was not correlated with age or degree of motor impairment. Dysphagia was significantly correlated with drooling at rest and both dysphagia and drooling at rest were correlated with degree of motor impairment. The 2 groups did not differ in the degree of drooling at rest. Among healthy children, age but not SPM demonstrated a significant inverse correlation with drooling quotient at rest.ConclusionsSpontaneous swallowing frequency is related to dysphagia and drooling in children with cerebral palsy. The pattern of relationships among spontaneous swallowing frequency and drooling is different between children with cerebral palsy and younger healthy children.     

Cross-sectional Analysis of Recommendations for the Treatment of Hip and Knee Osteoarthritis in Clinical Guidelines

ObjectiveTo compare guideline recommendations for hip and knee osteoarthritis (OA) and their level of evidence.Data SourcesMEDLINE, Embase, the Cochrane Library, and websites of professional societies were searched in June 2020 using keywords such as knee or hip osteoarthritis, degenerative arthritis, guideline, and practice guideline.Study SelectionGeneral treatment guidelines for OA of the hip or knee published in English. After 461 abstracts were screened, 31 publications (17 guidelines from 10 professional societies) were included for analysis.Data ExtractionThree reviewers assessed the quality of the guidelines according to the Appraisal of Guidelines for Research and Evaluation II tool. The rating of evidence and strength of recommendation was extracted and standardized into the Grading of Recommendations Assessment, Development, and Evaluation criteria.Data SynthesisOf the 17 guidelines included, 6 (35%) were of high quality, 10 (59%) of moderate quality, and 1 (6%) of low quality. Guidelines published after 2017 were of good quality. Although guidelines generally agreed on a nonsurgical multimodal concept, including patient education, exercise, and weight loss in obese, some recommendations remained vague and the level of evidence varied widely. In pharmacologic treatment, oral nonsteroidal anti-inflammatory drugs were the mainstay for pain management. Guidelines published after 2017 were more cautious in their recommendation for the use of paracetamol and strong opioids. Disagreement was observed for chondroitin sulfate, glucosamine, and intra-articular hyaluronic acid injections. Recommendations were conflicting for the use of insoles, braces, and transcutaneous electrical stimulation. The main indications for hip/knee arthroplasty were severe, persisting pain and loss of function despite nonsurgical treatment. No guideline defined a minimum time of conservative treatment before surgery.ConclusionsWe found a wide variation in evidence and strength of recommendations for OA treatment. Recommendations on when to refer patients for surgery remained unclear.     

Effects of Virtual Reality Intervention on Neural Plasticity in Stroke Rehabilitation: A Systematic Review

ObjectiveTo systematically review and examine the current literature regarding the effects of virtual reality (VR)–based rehabilitation on neural plasticity changes in survivors of stroke.Data SourcesWe searched 6 bioscience and engineering databases, including Medline via EBSCO, Embase, PsycINFO, IEEE Explore, Cumulative Index of Nursing and Allied Health, and Scopus.Study SelectionWe selected studies reporting on the pre-post assessment of a VR intervention with neural plasticity measures published between 2000 and 2021.Data ExtractionTwo independent reviewers conducted study selection, data extraction, and quality assessment. They assessed methodological quality of controlled trials using the Physiotherapy Evidence Database scale and evaluated risk of bias of pre-post intervention and case studies using the National Institutes of Health Quality Assessment Tool.Data SynthesisWe included 27 studies (n=232). We rated 7 randomized-controlled trials as good quality and 2 clinical-controlled trials as moderate. Based on the risk of bias assessment, we graded 1 pre-post study and 1 case study as good quality, 1 pre-post study and 1 case study as poor, and the other 14 studies as fair. After the VR intervention, main neurophysiological findings across studies include: (1) improved interhemispheric balance; (2) enhanced cortical connectivity; (3) increased cortical mapping of the affected limb muscles; (4) the improved neural plasticity measures were correlated to the enhanced behavior outcomes; (5) increased activation of regions in frontal cortex; and (6) the mirror neuron system may be involved.ConclusionsVR-induced changes in neural plasticity for survivors of stroke. Positive correlations between the neural plasticity changes and functional recovery elucidates the mechanisms of VR-based therapeutic effects in stroke rehabilitation. This review prompts systematic understanding of the neurophysiological mechanisms of VR-based stroke rehabilitation and summarizes the emerging evidence for ongoing innovation of VR systems and application in stroke rehabilitation.