Evaluation of Wire Electrodes to Activate the Expiratory Muscles to Restore Cough

描述（由申请人提供）：本申请涉及广泛的挑战领域（06）使能技术和特定挑战主题，06- ns -104：开发和验证辅助神经技术。呼吸系统并发症是脊髓损伤患者的重要发病率和死亡率，因为它们不能咳嗽和清除分泌物。这些人缺乏有效的咳嗽机制，因为他们的受伤经常导致几乎所有的呼气肌瘫痪。因此，这些患者依赖于护理人员协助应用手动吸痰，辅助咳嗽操作或其他气道管理方法。这些方法很麻烦，通常不舒服，需要训练有素的人员，并且经常限制患者的行动能力。由于大多数患者损伤水平以下的脊髓是完整的，脊髓的运动神经元和周围神经肌肉装置保持功能。因此，呼气肌应适应功能性电刺激技术，以恢复有效的咳嗽机制。在一项针对四肢瘫痪患者的试点研究中，我们最近表明，通过脊髓刺激可以电激活呼气肌，这种方法包括通过椎板切开术切口植入椎间盘电极。电极被放置在背侧硬膜外间隙，在胸椎下部和腰椎上部水平。本研究的结果表明，该方法成功地实现了呼气肌激活的有效手段，正如产生大气道压力和峰值气流速率所证明的那样。重要的是，这项技术有助于分泌物的清除，减少了对护理人员支持的需求，减少了呼吸道感染的发生率，提高了生活质量。因此，这项技术具有降低医疗费用和提高脊髓损伤患者生存率的潜力。虽然成功，但许多脊髓损伤患者不愿采用这种技术，因为电极放置需要侵入性手术。然而，我们的假设是，类似的呼气肌激活可以通过导线电极来实现，导线电极可以通过针经皮插入，消除了侵入性椎板切开术的需要，可以在门诊进行。后一种方法将增加患者和医生对该技术的接受度，缩短恢复时间并显著降低成本。因此，这项工作的目的是直接比较导线电极与先前使用的圆盘电极的功效。在6例接受碟状电极永久植入以恢复咳嗽的患者中，我们计划直接比较暂时放置几种不同的金属丝电极系统与碟状电极所达到的呼气肌激活程度。通过监测在手术室使用不同电极系统进行电刺激时气道压力的变化和产生的峰值气流速率来比较呼气肌的激活程度。该试验的结果将提供a)关于导致最佳呼气肌激活的丝电极的大小和刺激配置的至关重要的数据，b)使用微创技术恢复咳嗽的其他人体研究的框架，以及c)关于使用丝电极通过脊髓刺激恢复咳嗽的研究器械豁免（IDE）可能修改的必要数据。

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (06) Enabling Technologies and Specific Challenge Topic, 06-NS-104: Developing and validating assistive neuro-technologies. Respiratory complications account for significant morbidity and mortality in patients with spinal cord injury due to their inability to cough and clear secretions. These individuals lack an effective cough mechanism due to the fact that their injury often results in paralysis of virtually all of their expiratory muscles. Consequently these patients are dependent upon caregiver assistance for the application of manual suctioning, assisted coughing maneuvers or other methods of airway management. These methods are cumbersome, generally uncomfortable, require trained personnel and often restrict patient mobility. Since the spinal cord below the level of injury is intact in most patients, the motoneurons of the spinal cord and peripheral neuromuscular apparatus remain functional. Therefore, the expiratory muscles should be amenable to functional electrical stimulation techniques to restore an effective cough mechanism. In a single site, pilot study in tetraplegic subjects, we have recently shown that the expiratory muscles can be electrically activated by spinal cord stimulation, a method which involves the surgical placement of disc electrodes through laminotomy incisions. Electrodes are positioned in the dorsal epidural space at the lower thoracic and upper lumbar spinal levels. The results of this study indicate that this method is successful in achieving an effective means of expiratory muscle activation, as demonstrated by the generation of large airway pressures and peak airflow rates. Importantly, this technique facilitates secretion removal, reduces the need for caregiver support, reduces the incidence of respiratory tract infections and improves life quality. This technique therefore has the potential to reduce health care costs and improve survival in spinal cord injured subjects. While successful, many individuals with spinal cord injury are reluctant to pursue this technique due to the invasive procedure required for electrode placement. It is our hypothesis however that comparable activation of the expiratory muscles can be achieved with wire electrodes which can be inserted percutaneously through a needle, eliminating the need for the invasive laminotomy procedure and can be performed on an out-patient basis. This latter procedure would increase patient and physician acceptance of this technique, shorten recovery times and significantly reduce costs. The purpose of this undertaking therefore is to directly compare the efficacy of wire electrodes vs the previously employed disc electrodes. In 6 patients undergoing permanent implantation of disc electrodes to restore cough, we plan to directly compare the degree of expiratory muscle activation achieved with temporary placement of several different wire electrode systems with the disc electrodes. The degree of expiratory muscle activation will be compared by monitoring the changes in airway pressure and peak airflow rate generation achieved during electrical stimulation with different electrode systems in the Operating Room. The results of this trial will provide a) critically important data concerning the size and stimulus configuration of wire electrodes resulting in optimal expiratory muscle activation, b) the framework for additional human studies utilizing minimally invasive techniques to restore cough and c) necessary data for a possible amendment of our Investigational Device Exemption (IDE) to restore cough via spinal cord stimulation, with regard to use of wire electrodes. PUBLIC HEALTH RELEVANCE: Due to their inability to cough, respiratory complications such as pneumonia are a major cause of disability and death in subjects with spinal cord injury. The purpose of the proposed study is to evaluate a minimally invasive method of electrical activation of the expiratory muscles to restore cough utilizing spinal cord wire electrodes which can be inserted percutaneously. This technique would likely have wide patient and physician acceptance, significantly reduce the need for caregiver support, facilitate management of respiratory secretions, reduce the incidence of respiratory tract infections, reduce costs and improve life quality in this patient population.