Electrical Stimulation for Hemiplegic Shoulder Pain

卒中后肩痛是一个主要的康复问题，影响多达60%的中到重度受损的卒中幸存者。1卒中后肩痛与较差的康复结果有关，包括日常生活能力受损2和生活质量(QOL)。3多个随机临床试验(RCT)显示，对偏瘫肩周围肌肉的表面电刺激(ES)是唯一有效的干预措施。 尽管有证据表明表面电刺激对治疗有好处，但由于几个原因，表面电刺激治疗中风后肩痛的临床实施一直很困难。首先，皮肤疼痛感受器的刺激是不可避免的。虽然一些中风幸存者能够耐受每日一到两小时的表面ES治疗，但许多人不能耐受所需的6小时。其次，为了最大限度地减少刺激引起的疼痛，ES以相对较高的频率提供，频率在20至35赫兹之间，这会导致肌肉疲劳的发生更快。7第三，由于刺激引起的疼痛和肌肉疲劳，需要不断增加刺激计划。最后，需要临床技能或高强度的患者培训，以便每天可靠地放置电极并调整刺激参数，以提供最佳和可耐受的治疗，并将肌肉疲劳降至最低。 因此，贝克和帕克，表面电刺激治疗中风后肩部功能障碍的第一次临床试验的作者，得出结论说，直到植入的电极系统变得可用…长期使用体表电刺激只能由少数患者…管理和他们的家人。“8(1937页) 为了解决表面电刺激的局限性，研究小组率先开发了经皮肌肉内电刺激(IM)治疗中风后肩部疼痛。9-14由于电极被植入运动点，因此不需要熟练的人员和密集的患者培训来确保每一次治疗过程中电极的正确放置。10、12、15 IM E比表面ES痛苦更少，耐受性更好。13、16因此，IM ES可以以较低的刺激频率提供，这与 减少肌肉疲劳。7 IM的疼痛和疲劳减轻，不需要繁琐的不断升级的刺激计划。因此，ES和肌肉收缩是可靠的，患者对治疗方案的依从性很强。14调查组完成了一项随机对照试验，证明了与吊带相比，IM ES在减少中风后肩部疼痛方面的有效性。11、14特设后分析进一步确定，中风发病时间(18-月)是治疗成功的重要预测因素。 IM ES的初步效果已经得到证明。然而，在被临床社区接受之前，需要解决科学和临床知识中的其他差距。1)到目前为止，IM ES只是被比作吊带。研究人员的随机对照试验(RCT)不能与“日常护理”相提并论。 根据简明疼痛问卷(BPI)问题23显示疼痛相关生活质量的改善；然而，尽管这一测量已被验证为BPI电池的一个组成部分，但它尚未被验证为生活质量的测量。3)IMES减轻肩痛的作用机制尚未得到严格的评价。 为了开始解决这些问题，拟议的研究被设计为相对有效性的单盲探索性随机对照试验。主要目的是评估与IM ES和“常规护理”相关的疼痛减轻的相对效果。考虑到最低限度地增加成本和风险 在侵入性手术中，IM ES相对于“常规护理”的优越性需要得到证明。我们将使用这些估计来设计和推动一项更大规模的有效性试验。第二个目标是评估疼痛减轻对生活质量的影响。生活质量改善的证明将验证干预的临床相关性。最后，我们将探索机制。机制的阐明将进一步指导干预措施的完善。我们假设ES通过改善 肘关节-肱骨稳定性。因此，我们将评估这些治疗方法对肩关节三维僵硬特性的相对影响。我们进一步推测，ES通过促进运动恢复来改善关节-肱骨稳定性。因此，我们将评估这些治疗方法对中风后运动恢复的客观指标的影响。

Post-stroke shoulder pain is a major rehabilitation problem affecting up to 60% of moderate to severely impaired stroke survivors.1 Post-stroke shoulder pain is associated with poor rehabilitation outcomes, including impaired activities of daily living2 and poor quality of life (QOL).3 Surface electrical stimulation (ES) of muscles surrounding the hemiparetic shoulder is the only intervention with evidence of efficacy from multiple randomized clinical trials (RCT).4-6 Despite the evidence for therapeutic benefit, the clinical implementation of surface ES for post-stroke shoulder pain has been difficult for several reasons. First, stimulation of cutaneous pain receptors cannot be avoided. While some stroke survivors are able to tolerate one or 2-hrs of daily surface ES therapy, many are not able to tolerate the required 6-hrs. Second, in order to minimize the stimulation-induced pain, ES is delivered at a relatively high frequency between 20 and 35 Hz, which can lead to more rapid onset of muscle fatigue.7 Third, due to stimulation-induced pain and muscle fatigue, an escalating stimulation schedule is needed. Finally, clinical skill or intensive patient training is required to reliably place electrodes on a daily basis and adjust stimulation parameters to provide optimal and tolerable treatment with minimal muscle fatigue. Accordingly, Baker and Parker, the authors of the first clinical trial of surface ES for post-stroke shoulder dysfunction, concluded “Until implanted electrode systems become available… long-term use of surface electrical stimulation can be managed by only a few patients… and their families.”8(p1937) In order to address the limitations of surface ES, the investigative team pioneered the development of percutaneous intramuscular (IM) ES for the treatment of post-stroke shoulder pain.9-14 Since electrodes are implanted into motor points, skilled personnel and intense patient training are not needed to ensure proper placement of electrodes for each treatment session.10, 12, 15 IM ES is less painful and better tolerated then surface ES.13, 16 Therefore, IM ES can be delivered at a lower stimulation frequency, which is associated with reduced muscle fatigue.7 The reduced pain and fatigue of IM ES obviate the need for a cumbersome escalating stimulation schedule. Accordingly, the ES and muscle contraction are reliable and there is strong patient adherence to treatment regimen.14 The investigative team completed a RCT that demonstrated the efficacy of IM ES in reducing post-stroke shoulder pain in comparison to a sling.11, 14 Post-hoc analysis further identified time from stroke onset (<18-mo) as an important predictor of treatment success.9 The initial efficacy of IM ES has been demonstrated. However, prior to acceptance by the clinical community, additional gaps in the scientific and clinical knowledge need to be addressed. 1) To date, IM ES has only been compared to a sling. It has not been compared to “usual care.” 2) The investigators’ RCT showed improvements in pain related QOL based on Brief Pain Inventory (BPI) question 23; however, while this measure has been validated as a component of the BPI battery, it has not been validated as a measure of QOL. 3) The mechanism of action of IM ES in reducing shoulder pain has not been rigorously evaluated. In order to begin addressing these issues, the proposed study is designed as a comparative effectiveness single-blinded exploratory RCT. The primary objective is to estimate the relative effect sizes of pain reduction associated with IM ES and “usual care.” Given the added costs and risks of a minimally invasive procedure, the superiority of IM ES over “usual care” needs to be demonstrated. We will use these estimates to design and power a larger effectiveness trial. The secondary objective is to evaluate the impact of pain reduction on quality of life. Demonstration of improvement in quality of life will validate the clinical relevance of the intervention. Finally, we will explore mechanisms. The elucidation of mechanisms will further guide the refinement of the interventions. We postulate that ES reduces shoulder pain by improving glenohumeral stability. Thus we will evaluate the relative effects of these treatments on 3-dimensional stiffness characteristics of the glenohumeral joint. We further postulate that ES improves glenohumeral stability by facilitating motor recovery. Thus we will evaluate the effects of these treatments on objective measures of poststroke motor recovery.