【晨读】脊髓电刺激（八）

 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ROCK AK , Truong H , Park YL, et al. Spinal Cord Stimulation[J]. Neurosurg Clin N Am, 2019, 30(2):169-194.本次学习由谢珺田副主任医师主讲。

HF10 has been shown to have equivalent or superior outcomes to tonic SCS in patients with chronic back and leg pain, with response rates of 76.5% for HF10 SCS and 49.3% for tonic SCS. Burst stimulation also offers promise in RCT. Additional value may result from high-density programming, which provides stimulation at higher frequencies and delivery of higher charges per second. Algorithmic programming, which uses patient-specific, three-dimensional model-based neural targeting, demonstrates sustained relief of back pain at 24 months. Most recently, efficacy of closed-loop SCS systems using evoked compound action potentials can maintain desired levels of stimulation. Profound responses of 80% overall pain relief in 64.3% of patients at 6 months have been reported. The impact of new waveforms on increasing numbers of patients that benefit from SCS and prevention from habituation are currently under study.

HF10对慢性腰腿痛患者的疗效与强直电刺激相当或优于强直电刺激，HF10-SCS和强直SCS的有效率分别为76.5%和49.3%。爆发刺激在随机对照试验中也显示了良好的应用前景。高密度编程带来的结果，是可提供更高频率的刺激和每秒更高的电荷消耗。基于三维模型神经定位、适用于特定病人的算法编程应用研究报道，背痛可持续缓解24个月。最近，运用诱发复合动作电位的闭环SCS系统的效能可以稳定维持期望的刺激水平。据报道，6个月时，64.3%的患者总疼痛缓解率达到80%。目前SCS新波形编程研究让越来越多的患者获益，而对于患者习惯化影响的相关研究也在进展之中。

Adjuncts

A summary of results from studies evaluating adjuncts to SCS therapy are presented in Table 7.  The standard goal for SCS is to reduce each patients’ pain by 50%. This is obtained through a multimodal approach. First, SCS programming should be performed as an iterative process because pain symptoms change over time and regularly scheduled visits allow for ongoing fine-tuned adjustments of care. One feared complication of SCS is habituation, where patients become accustomed to the effects of stimulation. Theoretically, this is minimized by varying the signal and its focal point, which creates alternating waveforms. Whether habituation occurs with ongoing changes in waveforms of stimulation has not been truly elucidated. Medications may also be used concurrently with SCS to optimize pain relief. Specifically, baclofen in addition to SCS has been shown to produce greater pain relief than SCS alone. Intrathecal clonidine and oral duloxetine have each independently shown similar adjunctive benefits. With the growing recognition of the ongoing opioid epidemic, it should be heavily emphasized that patients on opioids at time of implantation who continue opioid use at similar doses tend to have poorer long-term outcomes.

辅助药物

表7总结了评估SCS治疗辅助药物的研究结果。SCS的治疗目标是将每位患者的疼痛减少50%。这是通过多模式方法实现的。首先，SCS编程应该是一个动态的过程，因为疼痛症状会随着时间的推移而改变，并且医护人员定期访视可随时进行反复的微调。SCS的一个可怕的并发症是习惯化，即患者习惯于刺激的效果。从理论上讲，通过改变信号及其焦点产生交替波形，可以大大减少习惯化的产生。而相关研究尚未证实，习惯化是否随着刺激波形的持续变化而发生。药物也可以与SCS同时使用，以达到最大程度的疼痛缓解。特别是巴氯芬，已有研究证明与SCS联用比单用SCS疼痛缓解更为显著。鞘内注射可乐定和口服度洛西汀各有相似的辅助作用。随着人们对正随着对于现行阿片类药物的认识不断深入，应该着重强调，在植入SCS时服用阿片类药物的患者如果术后继续使用同样剂量的阿片类药物，其长期疗效往往较差。

ECONOMIC EVALUATION

Despite the high cost of SCS, several studies have demonstrated long-term cost-effectiveness of SCS when compared with CMM alone. A RCT using crossover design with SCS versus reoperation for FBSS showed that the cost per patient for long-term success with SCS and reoperation were $48,357 and $105,928, respectively. SCS was most cost-effective when patients did not attempt reoperation before SCS, and reoperation did not succeed in relieving pain in any patient where SCS was previously unsuccessful. A review of 128 patients who underwent SCS or peripheral nerve stimulation found that on average $93,685 was saved over 3.1 years of implantation as compared with health care expenditures before device implantation. Among patients with CRPS, the costs of treatment with SCS within the first year were $4000 more than control subjects, but lifetime analysis demonstrated a savings of $60,000. In 2017, comparisons across commercial, Medicaid, and Medicare cohorts demonstrated cost-effectiveness in all groups for periods from 2 to 9 years of follow-up following implantation.

费用评估

尽管SCS的成本很高，但一些研究表明， SCS长期治疗的效价比优于CMM。采用交叉设计的随机对照试验（RCT）与FBSS再次手术的比较显示，SCS和再次手术长期成功的每位患者的成本分别为48357美元和105928美元。当患者在SCS之前没有尝试再次手术时，SCS效价比最高，并且在先前SCS无效的患者，再次手术往往也不能有效缓解疼痛。对128名接受SCS或周围神经刺激的患者的回顾研究发现，与植入前的医疗费用相比，植入3.1年平均节省了93685美元。在CRPS患者中，第一年内用SCS治疗的费用比对照组多4000美元，但生存分析显示节省了60000美元。2017年，商业保险、医疗补助和医疗保险队列研究结果显示，植入后2至9年随访期间，所有各组的效价比都很高。

SUMMARY

SCS is commonly used for the treatment of FBSS, CRPS, and neuropathic pain. There is level 1 evidence to support its use in FBSS and CRPS.  Careful patient selection including a rigorous trial period and psychological evaluation are essential. When patients proceed to permanent implantation, various considerations should be made, such as the type of lead, type of anesthesia, and waveform. This decision-making process is multifactorial and must take into account characteristics unique to each patient and workflow of each operative team.  New waveforms hold promise for improving pain relief, but their mechanisms of action still need to be elucidated. Finally, the evidence to date suggests SCS is cost-effective when compared with CMM and this should be emphasized when patients and insurers face the upfront economic costs.

结论

SCS通常用于治疗FBSS、CRPS和神经病理性疼痛。有1级证据支持其在FBSS和CRPS中的应用。认真选择病例，包括严格的测试治疗和心理评估是必不可少的。当患者考虑接受永久电极植入时，应评估各种因素，如电极类型、麻醉方式和波形编程方案。这个决策过程是多因素的，必须考虑到每个病人的特点和每个手术团队的工作流程。新的波形编程有望改善疼痛缓解程度，但其作用机制仍有待进一步阐释。最后，迄今为止的证据表明，与CMM相比，SCS长期性价比较高，当患者和保险公司质疑前期费用较高时，应强调这一点。