脊髓电刺激诱发复合动作电位仿真研究  

Simulation study of spinal cord stimulation evoked compound action potential

作　　者：张广浩[1,2] 张丞 吴昌哲[1] 霍小林 ZHANG Guanghao;ZHANG Cheng;WU Changzhe;HUO Xiaolin(Beijing Key Laboratory of Bioelectromagnetism,Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,P.R.China;School of Electronics,Electrical and Communication Engineering,University of Chinese Academy of Sciences,Beijing 100049,P.R.China)

机构地区：[1]中国科学院电工研究所生物电磁学北京市重点实验室,北京100190 [2]中国科学院大学电子电气与通信工程学院,北京100149

出　　处：《生物医学工程学杂志》2021年第2期232-240,共9页Journal of Biomedical Engineering

基　　金：国家重点研发计划项目(2016YFC0105502);国家自然科学基金(61671428)。

摘　　要：脊髓电刺激(SCS)治疗慢性疼痛以一种开环的方式植入,植入后刺激参数一般保持不变。为了避免电极位置变化引起刺激强度不足或过度刺激,可以利用SCS电极记录的诱发复合动作电位(ECAP)作为反馈信号,来调整刺激参数。本文建立了SCS同步记录ECAP的仿真模型,并研究ECAP波形与脊髓背侧柱(DC)纤维兴奋程度之间的关系。通过SCS有限元仿真模型和感觉纤维多房室电缆模型的耦合计算SCS作用下由膜电流引起的单纤维动作电位(SFAP),将SFAP叠加获得电极上记录的差分形式的ECAP信号。仿真结果表明ECAP中不同的波谷对应着不同直径的感觉纤维,由波谷位置和幅值可以判断DC纤维兴奋程度。不超过10%DC纤维兴奋时的ECAP波谷对应着大直径感觉纤维,20%及以上DC纤维兴奋时出现慢传导的波谷,对应着小直径感觉纤维,且DC纤维兴奋程度越高,波谷幅值越大,但大直径纤维对应的波谷幅值保持不变。本文建立的SCS同步采集ECAP仿真模型可以模拟ECAP信号并由波谷位置和幅度判断DC纤维兴奋程度,进而判定刺激强度过小、适当或过大,为基于ECAP的闭环SCS在未来的临床应用提供理论依据。Spinal cord stimulation(SCS)for pain is usually implanted as an open loop system using unchanged parameters.To avoid the under and over stimulation caused by lead migration,evoked compound action potentials(ECAP)is used as feedback signal to change the stimulating parameters.This study established a simulation model of ECAP recording to investigate the relationship between ECAP component and dorsal column(DC)fiber recruitment.Finite element model of SCS and multi-compartment model of sensory fiber were coupled to calculate the single fiber action potential(SFAP)caused by single fiber in different spinal cord regions.The synthetized ECAP,superimposition of SFAP,could be considered as an index of DC fiber excitation degree,because the position of crests and amplitude of ECAP corresponds to different fiber diameters.When 10%or less DC fibers were excited,the crests corresponded to fibers with large diameters.When 20%or more DC fibers were excited,ECAP showed a slow conduction crest,which corresponded to fibers with small diameters.The amplitude of this slow conduction crest increased as the stimulating intensity increased while the amplitude of the fast conduction crest almost remained unchanged.Therefore,the simulated ECAP signal in this paper could be used to evaluate the degree of excitation of DC fibers.This SCS-ECAP model may provide theoretical basis for future clinical application of close loop SCS base on ECAP.

关 键 词：脊髓电刺激 房室模型 有限元模型 闭环刺激 诱发复合动作电位 

分 类 号：R318[医药卫生—生物医学工程]