Abstract：
OBJECTIVE: Spinal cord stimulation (SCS) is a surgical treatment for severe, chronic, neuropathic pain. It is based on one to two lead(s) implanted in the epidural space, stimulating the dorsal column. It has long been assumed that when deactivating SCS, there is a variable interval before the patient perceives the return of the pain, a phenomenon often termed echo or carryover effect. Although the carryover effect has been problematized as a source of error in crossover studies, no experimental investigation of the effect has been published. This open, prospective, international multicenter study aimed to systematically document, quantify, and investigate the carryover effect in SCS.
METHODS: Eligible patients with a beneficial effect from their SCS treatment were instructed to deactivate their SCS device in a home setting and to reactivate it when their pain returned. The primary outcome was duration of carryover time defined as the time interval from deactivation to reactivation. Central clinical parameters (age, sex, indication for SCS, SCS treatment details, pain score) were registered and correlated with carryover time using nonparametric tests (Mann-Whitney/Kruskal-Wallis) for categorical data and linear regression for continuous data.
RESULTS: In total, 158 patients were included in the analyses. A median carryover time of five hours was found (interquartile range 2.5;21 hours). Back pain as primary indication for SCS, high-frequency stimulation, and higher pain score at the time of deactivation were correlated with longer carryover time.
CONCLUSIONS: This study confirms the existence of the carryover effect and indicates a remarkably high degree of interindividual variation. The results suggest that the magnitude of carryover may be correlated to the nature of the pain condition and possibly stimulation paradigms.
BACKGROUND: The Clinicaltrials.gov registration number for the study is NCT03386058.
METHODS: Eligible patients with a beneficial effect from their SCS treatment were instructed to deactivate their SCS device in a home setting and to reactivate it when their pain returned. The primary outcome was duration of carryover time defined as the time interval from deactivation to reactivation. Central clinical parameters (age, sex, indication for SCS, SCS treatment details, pain score) were registered and correlated with carryover time using nonparametric tests (Mann-Whitney/Kruskal-Wallis) for categorical data and linear regression for continuous data.
RESULTS: In total, 158 patients were included in the analyses. A median carryover time of five hours was found (interquartile range 2.5;21 hours). Back pain as primary indication for SCS, high-frequency stimulation, and higher pain score at the time of deactivation were correlated with longer carryover time.
CONCLUSIONS: This study confirms the existence of the carryover effect and indicates a remarkably high degree of interindividual variation. The results suggest that the magnitude of carryover may be correlated to the nature of the pain condition and possibly stimulation paradigms.
BACKGROUND: The Clinicaltrials.gov registration number for the study is NCT03386058.
摘要：
目的：脊髓刺激（SCS）是一种严重的手术治疗方法，慢性，神经性疼痛。它是基于植入硬膜外腔的一到两根导线，刺激背柱。长期以来，人们一直认为，当停用SCS时，在患者感觉到疼痛的复发之前有一个可变的间隔，一种通常被称为回声或残留效应的现象。尽管结转效应在交叉研究中被认为是错误的来源，尚未发表有关该效应的实验研究。这个开放的，prospective,国际多中心研究旨在系统地记录，量化、并研究SCS的遗留效应。
方法：符合SCS治疗效果的患者被指导在家中停用SCS装置，并在疼痛恢复时重新激活。主要结果是保留时间的持续时间，定义为从去激活到再激活的时间间隔。中心临床参数（年龄，性别,SCS指示,SCS治疗详情,对疼痛评分)进行登记,并使用非参数检验(Mann-Whitney/Kruskal-Wallis)对分类数据进行关联,对连续数据进行线性回归.
结果：总计，158名患者被纳入分析。发现中位结转时间为5小时(四分位数间距2.5;21小时)。背痛是SCS的主要指征，高频刺激,停用时较高的疼痛评分与较长的遗留时间相关。
结论：这项研究证实了结转效应的存在，并表明个体间的变异程度非常高。结果表明，残留的程度可能与疼痛状况的性质以及可能的刺激范例有关。
背景：本研究的Clinicaltrials.gov注册号为NCT03386058。
方法：符合SCS治疗效果的患者被指导在家中停用SCS装置，并在疼痛恢复时重新激活。主要结果是保留时间的持续时间，定义为从去激活到再激活的时间间隔。中心临床参数（年龄，性别,SCS指示,SCS治疗详情,对疼痛评分)进行登记,并使用非参数检验(Mann-Whitney/Kruskal-Wallis)对分类数据进行关联,对连续数据进行线性回归.
结果：总计，158名患者被纳入分析。发现中位结转时间为5小时(四分位数间距2.5;21小时)。背痛是SCS的主要指征，高频刺激,停用时较高的疼痛评分与较长的遗留时间相关。
结论：这项研究证实了结转效应的存在，并表明个体间的变异程度非常高。结果表明，残留的程度可能与疼痛状况的性质以及可能的刺激范例有关。
背景：本研究的Clinicaltrials.gov注册号为NCT03386058。
