【原】【省立疼痛英语晨读】脊髓电刺激程控：速成课程（七）

 英语晨读 ·

山东省立医院疼痛科英语晨读已经坚持10余年的时间了，每天交班前15分钟都会精选一篇英文文献进行阅读和翻译。一是可以保持工作后的英语阅读习惯，二是可以学习前沿的疼痛相关知识。我们会将晨读内容与大家分享，助力疼痛学习。

本次文献选自Sheldon B , Staudt M D , Williams L , et al. Spinal cord stimulation programming: a crash course[J]. Neurosurgical Review, 2020:1-12.

Amplitude

This parameter determines how robustly the stimulation will be felt, with higher amplitudes resulting in stronger and more intense paresthesias for tonic stimulation. Programming amplitude amounts to achieving a delicate balance: the chosen value should provide enough stimulation to sufficiently mask the patient’s pain, while avoiding discomfort and excessive drain on the battery. Each patient will have a different threshold for perception and discomfort, and starting amplitudes during programming are typically low (between 1 and 5 mA) to allow for slow titration and identification of these thresholds. Subparesthesia programs require more thoughtful adjustment as the sensory threshold is not reached, and amplitude should be adjusted with gradual increases and attention paid to responses potentially caused by affecting multiple structures. For burst stimulation specifically, paresthesias should not be felt as that is an indicator that the stimulation is too high which may cause hyperalgesia.

振幅

这个参数决定了对刺激的感觉强度，对于兴奋性刺激，较高的振幅会导致更大更强烈的感觉异常。设定振幅应达到微妙的平衡：所选的值应提供足够的刺激，以充分覆盖患者的疼痛部位，同时避免不适和电池的过度损耗。每个患者的感知和不适感阈值都不同，程控期间的起始振幅通常较低（介于1和5 mA之间），以便于缓慢滴定和识别这些阈值。由于未达到感觉阈值，亚感觉异常程序需要更加深思熟虑的调整，振幅应逐渐调整，缓慢增加，并注意影响多种结构可能引起的反应。特别是对于爆发式刺激，不应有感觉异常，否则可能是刺激过高可能引起痛觉过敏。

By definition, amplitude is the measure of power output from the IPG, and can be measured in current (milliamperes, mA) or voltage (V). The IPG can employ either a constant current or constant voltage, in which the respective parameters are adjusted based on the impedance encountered. For example, in constant current systems, the voltage changes in response to impedance, whereas in constant voltage systems, it is the current that changes. As such, impedance changes in constant voltage systems can result in decreased stimulation amplitudes, theoretically affecting stimulation efficiency and efficacy. There may be subtle differences in the pulse waveforms produced, which may theoretically influence patient outcomes. The supporting literature is limited, with one preclinical study describing the use of constant current SCS as superior to constant voltage in reducing visceral nociceptive responses in rats. The clinical difference between these two types of stimulation remains unclear, with contradictory reports of patient preference in small studies. As such, further studies are required to validate the potential clinical utility of these systems.

根据定义，振幅是IPG输出功率的量度，可以以电流（mA）或电压（V）来度量。IPG可以采用恒定电流或恒定电压，根据所遇到的阻抗调整相应的参数。例如，在恒定电流系统中，电压根据阻抗而变化，而在恒定电压系统中，电流是变化的。这样，恒压系统中的阻抗变化会导致刺激振幅降低，从理论上影响刺激效率和效果。产生的脉冲波形可能会有细微的差异，理论上可能会影响患者的治疗效果。支持的文献有限，只有一项临床前研究显示在减少大鼠内脏伤害感受反应方面，使用恒定电流SCS优于恒定电压。这两种类型的刺激之间的临床差异尚不清楚，在小型研究中有关患者偏爱的报道相互矛盾。因此，需要进一步的研究来验证这些系统的潜在临床实用性。

As more current is added to the stimulation, energy rises, and the stimulation is perceived more strongly; however, this also results in accelerated battery depletion. Initially, programmers will determine the range of amplitude appropriate for an individual. The minimum amplitude is typically set at the lowest value perceived by the patient, with the maximum value set at where the stimulation begins to induce uncomfortable paresthesias or other side effects. A target range for initial tonic stimulation depends on the programmer and the patient; typically, this is set below 1–5 mA and gradually increased until optimal pain control is achieved or stimulation becomes uncomfortable. Starting amplitudes for cervical lead programming is typically lower (i.e., less than 1 mA). Once an optimal amplitude is chosen, a range will be set and the patient is permitted to adjust within that range depending on need.

当刺激中电流增加，能量上升，刺激感觉更强烈;然而，这也导致电池消耗加速。最初，医师将制定适合个人的振幅范围。最小振幅通常设置在患者感知的最小值，最大值设置为刺激开始引起不舒服的感觉异常或其他副作用时。初始刺激的目标范围取决于医师和患者；一般情况下，将其设置在1-5 mA以下，并逐渐增加，直到达到最佳的疼痛控制或刺激变得不舒服。颈部电刺激的起始振幅通常较低(即小于1 mA)。一旦选择了最佳振幅，就会设置一个范围，病人可以根据需要在该范围内进行调整。

During a trial, the patient’s desired amplitudes should be monitored to inform postoperative programming. Collison et al. conducted a prospective study using IOM to predict postoperative energy requirements. They found a significant relationship between the intraoperative amplitude needed to reach abdominal or extremity lateralization and postoperative amplitude to relieve pain. Their findings suggest that information gathered at the time of implant could be used to predict the energy requirements necessary to induce pain relief, thus streamlining battery selection and postoperative programming. The type of lead implanted is also an important consideration when predicting parameter settings. For example, paddle leads deliver a unidirectional flow of current and generally require lower amplitudes, due to their insulation design and large cross-sectional area. Compared to percutaneous leads, paddle leads require less energy for stimulation due to their lower load impedance, although this does not necessarily translate proportionally to improved battery life.

在测试期间，应监测患者所需的振幅，以便为术后程控提供信息。Collison等人进行了一项前瞻性研究，使用IOM预测术后的能量需求。他们发现术中到达腹部或偏侧肢体所需的振幅与术后缓解疼痛的所需的振幅之间有显著关系。他们的发现表明，植入时获得的信息可以用来预测缓解疼痛所需的能量需求，从而简化电池的选择和术后规划。在预测参数设置时，电极植入的类型也是一个重要的考虑因素。例如，片状电极提供单向电流，由于其绝缘设计和大的横截面积，通常要求较低的振幅。与经皮电极相比，片状电极由于其较低的负载阻抗而需要较少的能量用于刺激，当然这并不一定会成比例地提高电池寿命。