Natural Versus Artificial Sensors Applied in Peroneal Nerve Stimulation

Abstract: We have attempted to quantify the performance of natural versus artificial sensors when used in a closed-loop functional electrical stimulation system. Peroneal nerve stimulation was applied during gait to a multiple sclerosis subject with a drop foot. Stimulation was applied only during the swing phase to provide artificially induced dorsiflexion of the foot. Detection of the onset of the stance phase was accomplished using a standard heel contact switch mounted inside the subject's shoe (the artificial sensor) and using processed nerve signals derived from an implanted nerve-cuff electrode (the natural sensor). A detection percentage of at least 85% was achieved using the afferent nerve signal information only. When muscle activity (also recorded in the cuff) and additional information about the gait cycle were incorporated, functional detection ratios approaching 100% were achieved.     

Spinal cord stimulation in complex regional pain syndrome: cervical and lumbar devices are comparably effective

Background. Spinal cord stimulation (SCS) has been used since1967 for the treatment of patients with chronic pain. However,long-term effects of this treatment have not been reported.The present study investigated the long-term effects of cervicaland lumbar SCS in patients with complex regional pain syndrometype I. Methods. Thirty-six patients with a definitive implant wereincluded in this study. A pain diary was obtained from all patientsbefore treatment and 6 months and 1 and 2 years after implantation.All patients were asked to complete a seven-point Global PerceivedEffect (GPE) scale and the Euroqol-5D (EQ-5D) at each post-implantassessment point. Results. The pain intensity was reduced at 6 months, 1 and 2years after implantation (P<0.05). However, the repeatedmeasures ANOVA showed a statistically significant, linear increasein the visual analogue scale score (P=0.03). According to theGPE, at least 42% of the cervical SCS patients and 47% of thelumbar SCS patients reported at least ‘much improvement’.The health status of the patients, as measured on the EQ-5D,was improved after treatment (P<0.05). This improvement wasnoted both from the social and from the patients’ perspective.Complications and adverse effects occurred in 64% of the patientsand consisted mainly of technical defects. There were no differencesbetween cervical and lumbar groups with regard to outcome measures. Conclusion. SCS reduced the pain intensity and improves healthstatus in the majority of the CRPS I patients in this study.There was no difference in pain relief and complications betweencervical and lumbar SCS. Br J Anaesth 2004; 92: 348–53     

Further Development of Hybrid Functional Electrical Stimulation Orthoses

Abstract: In this study two aspects of hybrid functional electrical stimulation (FES) orthoses were investigated: joint motion constraints and FES control strategies. First, the effects of joint motion constraints on the gait of normal subjects were investigated using modern motion analysis systems, including electromyogram (EMG) and heart rate measurements. An orthosis was developed to impose joint motion constraints; the knee and ankle could be fixed or free, and the hip joint could rotate independently or coupled, according to a preset flexion-extension coupling ratio (FECR). Compared with a 1:1 hip FECR, a 2:1 hip FECR was associated with a reduced energy cost and increased speed and step length. The knee flexion during swing significantly reduced energy cost and increased walking speed. Ankle plantar flexion reduced the knee flexing moment during the early stance phase. Second, trials on 3 paraplegic subjects were conducted to implement some of these findings. It appeared that the 2:1 FECR encouraged hip flexion and made leg swing easier. A simple FES strategy increased walking speed and step length and reduced crutch force impulse using fixed orthotic joints.     

Temporal analysis of cortical mechanisms for pain relief by tactile stimuli in humans

The mechanisms by which vibrotactile stimuli relieve pain are not well understood, especially in humans. We recorded cortical magnetic responses to paired noxious (intra-epidermal electrical stimulation, IES) and innocuous (transcutaneous electrical stimulation, TS) stimuli applied to the back at a conditioning-test interval (CTI) of -500 to 500 ms. Results showed that IES-induced responses were remarkably attenuated when TS was applied 20-60 ms later and 0-500 ms earlier than IES (CTI = -60 to 500 ms). Since the signals evoked by IES reached the spinal cord (CTI = -60 to -20 ms conditions) and the cortex (-60 and -40 ms condition) earlier than those evoked by TS, the present results indicate that cortical responses to noxious stimuli can be inhibited by innocuous tactile stimuli at the cortical level, with minimal contribution at the spinal level.     

Spinal cord stimulation for relief of abdominal pain in two patients with familial Mediterranean fever

Familial Mediterranean fever is a hereditary disease characterizedby recurrent attacks of fever and serosal inflammation thatcommonly presents as severe abdominal pain. Though colchicineremains the mainstay of treatment, a significant proportionof patients are partially responsive, unresponsive or intolerantto it. We present two such cases where spinal cord stimulation(SCS) was used to manage the paroxysmal abdominal pain associatedwith this disease. Abdominal visceral pain pathways and theapplication of SCS techniques in its management are discussed.     

经皮神经电刺激在全膝关节置换术后多模式镇痛中的应用研究

目的：观察经皮神经电刺激治疗在全膝关节置换术后多模式镇痛方案中的应用疗效.方法：2009年3月至2012年5月在浙江省中医院骨伤科就诊,诊断为膝骨性关节炎需行单侧全膝关节置换术的患者60例,分为试验组和对照组,每组30例.所有患者术前口服塞来昔布,术中行膝关节腔周围注射,术后口服塞来昔布、硫酸吗啡控释片.试验组术后增加使用经皮神经电刺激治疗,每日1次.患者于术后24h开始做膝关节功能锻炼.记录患者术后各时间点疼痛视觉模拟评分、膝关节活动角度、不良反应等.结果：术后24、48、72 h及术后1周,试验组患者的疼痛评分分别为3.39±0.69,2.79±0.51,2.16±±0.52,1.07±0.57,均低于对照组患者的3.80±0.86,3.22±0.58,2.53±0.54,1.38±0.52.术后24、48、72 h及术后1周、2周,试验组患者的膝关节被动活动角度分别为（30.67±3.65）°,（39.17±3.96）°,（47.83±4.86）°,（93.67±7.30）°,（107.67±7.51）°;术后72 h及1、2周主动活动角度分别为（29.83±5.33）°,（78.33±8.24）°,（95.17±5.94）°;均高于对照组的（28.67±3.92）°,（36.83±4.25）°,（45.17±5.17）°,（89.83±7.25）°,（103.17±7.37）°和（24.17±10.26）°,（73.83±9.07）°,（91.33±7.42）°.试验组19例膝部皮肤出现不同程度环形瘀血性压迹,5例出现局部水泡.结论：将经皮神经电刺激治疗应用于全膝关节置换术后多模式镇痛可以降低患者术后疼痛评分,促进术后膝关节功能尽早恢复.     

The Accelograph®: a new neuromuscular transmission monitor

A new neuromuscular transmission monitor based on measurement of acceleration is presented. The monitor consists of an acceleration transducer, i.e. a piezo-electric ceramic wafer with an electrode on each side, and a stimulation and computing unit. The transducer can be fastened to the thumb, and when the finger is moved in response to nerve stimulation a voltage difference develops between the two electrodes. The voltage is then measured and registered in the computing unit. The acceleration transducer does not require preload, but merely that the muscle on which the measurement is being made can move freely. The accelograph is therefore easy to set up and operate. In daily clinical practice it has proved possible, using this new apparatus, to achieve reliable evaluation of the degree of non-depolarizing neuromuscular blockade in less than 2 min.     

Selective Detrusor Activation by Electrical Stimulation of the Human Sacral Nerve Roots

Abstract: The purpose of this study was to investigate the feasibility of selective detrusor activation without activation of the urethral sphincter by sacral root stimulation in patients. The sacral roots were stimulated using a tripolar electrode. An anodal block was used to prevent the urethral sphincter from contraction. Using square current pulses (700 μs, 6–7 mA), no increase in intraurethral pressure was measured, while a normal increase in intravesical pressure occurred. The minimum pulse duration to obtain a complete block was 550 μs. The study shows that anodal blocking of action potentials is possible in humans and can result in selective detrusor activation when used in sacral root stimulation.     

Percutaneous sacral nerve root neuromodulation for intractable interstitial cystitis

PURPOSE: We evaluated the efficacy of percutaneous sacral nerve root neuromodulation in women with refractory interstitial cystitis. MATERIAL AND METHODS: We prospectively evaluated 15 consecutive women with a mean age of 62 years who had refractory interstitial cystitis to determine the efficacy of percutaneous stimulation of the S3 sacral roots. The mean duration of symptoms before evaluation was 5.2 years. All women fulfilled the National Institute of Arthritis, Diabetes and Digestive and Kidney Diseases criteria for the diagnosis of interstitial cystitis and were unresponsive to standard oral or intravesical therapy. The response to treatment was assessed using pain scores, urinary diary variables and quality of life surveys. RESULTS: Mean voided volume during treatment increased from 90 to 143 ml. (p <0.001). Mean daytime frequency and nocturia decreased from 20 to 11 and 6 to 2 times (p = 0.012 and 0.007, respectively). Mean bladder pain decreased from 8.9 to 2.4 points on a scale of 0 to 10 (p <0.001). As indicated by the Short Urinary Distress Inventory and SF-36 Health Survey, the quality of life parameters of social functioning, bodily pain and general health significantly improved during the stimulation period. Of the women 73% requested to proceed to complete sacral nerve root implantation. CONCLUSION: Women with intractable interstitial cystitis respond favorably to percutaneous sacral stimulation with significant improvement in pelvic pain, daytime frequency, nocturia, urgency and average voided volume. Permanent sacral implantation may be an effective treatment modality in refractory interstitial cystitis but further long-term evaluation is required.     

七氟醚、异氟醚和地氟醚对神经外科手术患者经颅电刺激运动诱发电位的影响

目的 比较七氟醚、异氟醚和地氟醚对神经外科手术患者经颅电刺激运动诱发电位(MEPs)的影响.方法 择期行神经外科手术患者60例,年龄18～64岁,ASA分级Ⅰ或Ⅱ级.随机分为3组(n=20):七氟醚组、异氟醚组和地氟醚组.监测BIS值和经颅电刺激MEPs.调节七氟醚、异氟醚和地氟醚吸入浓度,使其呼气末浓度分别达到0.50、0.75、1.00和1.30 MAC,每一浓度均维持15 min,视为稳态呼气末浓度.于给予吸入麻醉药前(基础状态)和达到各稳态呼气末浓度(T1-4)时,记录MEPs的波幅和潜伏期以及BIS值.记录MEPs波形记录失败情况.结果 与七氟醚组和异氟醚组比较,地氟醚组T1.2时波幅和BIS值降低,T1-4时潜伏期延长(P＜0.05);七氟醚组和异氟醚组各指标比较差异无统计学意义(P＞0.05).七氟醚组、异氟醚和地氟醚组基础状态、T1、T2时的记录失败率均为0;T3时记录失败率分别为0、5%和20%,三组比较差异无统计学意义(P＞0.05);T4时记录失败率分别为5%、20%和45%,与七氟醚组和异氟醚组比较,地氟醚组记录失败率升高(P＜0.05);七氟醚组和异氟醚组比较差异无统计学意义(P＞0.05).结论 地氟醚对神经外科手术患者经颅电刺激MEPs的抑制作用强于七氟醚和异氟醚.术中行MEPs监测时,七氟醚和异氟醚适宜的呼气末浓度为1.00 MAC,地氟醚为0.75～1.00 MAC.     

经颅电刺激运动诱发电位和皮层体感诱发电位在脊柱侧凸手术中联合监护的观察研究

目的 探讨脊柱侧凸手术中经颅电刺激运动诱发电位(transcranial electrical stimulation motor evoked potential,TES-MEP)和皮层体感诱发电位(cortical somatosensory evoked potential,CSEP)联合监护的可行性和应用价值.方法 2006年7月至2008年4月,在脊柱侧凸手术中同时记录双侧胫前肌、足(足母)短屈肌TES-MEP和双侧胫后神经CSEP 76例.实施全静脉麻醉49例,七氟烷(吸入浓度＜1%)+异丙芬复合麻醉27例.对各麻醉组的TES-MEP检出结果 进行四格表χ2检验,并对术中两种电位的真、假阳性和真、假阴性结果 进行相关的指数统计分析.结果 TES-MEP和CSEP成功检出率均为96.1%,而两种麻醉组的TES-MEP检出率差异无统计学意义.术中诱发电位阳性11例,其中9例为真阳性,均与手术操作不当直接有关.CSEP、TES-MEP、联合监护的灵敏度分别为75.0%、87.5%和100%,特异度分别为98.5%、98.5%和97.0%,约登指数分别为0.74、0.86和0.97.结论 实施异丙芬静脉麻醉为主,辅以七氟烷吸入浓度＜1%的复合麻醉,也是联合监护切实町行的麻醉方案;联合监护对脊髓功能监测的敏感性和准确性明显高于单一的TES-MEP或CSEP监护.     

Lumbar Root Stimulation for Restoring Leg Function: Results in Paraplegia

Abstract: We have implanted an intradural array of 12 tripolar electrodes on the anterior roots L2-S2, left and right, at cauda equina level, in a 33-year-old woman with a complete T9 cord lesion of 3 years' duration. They are driven by an implanted multiplexed stimulator system using radio frequency (RF) power and control signals. All channels generate movements, in patterns that might be predicted from the known anatomy of the cauda equina. In particular, stimulation of L2 and L3 gives hip adduction; L3, L4, and L5 gives quadriceps femoris movements; L5, S1, and S2 gives hamstrings movement; and S1 and S2 give plantar flexion. Stimulation of L5 gives mixed movements at the ankle. Surprisingly, stimulation of the L2 roots has not given strong hip flexion. Responses have been stable. Some thresholds have varied, probably as a result of tissue encapsulation. The moment generated within each degree of freedom of the legs has been measured for each root, using a specially designed multimoment measurement apparatus. For several roots, a movement of lower threshold may be accompanied by a second movement of higher electrical threshold, suggesting that different muscles may have fiber populations that differ in their diameter or their location in the root. The use of stimulus forms that enable selective anodal block may, in the future, enable separation of two distinct movements from a single motor root.     

Measurement of motor evoked potentials following repetitive magnetic motor cortex stimulation during isoflurane or propofol anaesthesia

Background. Isoflurane and propofol reduce the recordabilityof compound muscle action potentials (CMAP) following singletranscranial magnetic stimulation of the motor cortex (sTCMS).Repetition of the magnetic stimulus (repetitive transcranialmagnetic stimulation, rTCMS) might allow the inhibition causedby anaesthesia with isoflurane or propofol to be overcome. Methods. We applied rTCMS (four stimuli; inter-stimulus intervalsof 3, 4, 5 ms (333, 250, 200 Hz), output 2.5 Tesla) in 27 patientsand recorded CMAP from the hypothenar and anterior tibial muscle.Anaesthesia was maintained with fentanyl 0.5–1 µgkg^–1 h^–1 and either isoflurane 1.2% (10 patients)or propofol 5 mg kg^–1 h^–1 with nitrous oxide 60%in oxygen (17 patients). Results. No CMAP were detected during isoflurane anaesthesia.During propofol anaesthesia 333 Hz, four-pulse magnetic stimulationevoked CMAP in the hypothenar muscle in 75%, and in the anteriortibial muscle in 65% of the patients. Less response was obtainedwith 250 and 200 Hz stimulation. Conclusions. In most patients, rTCMS can overcome suppressionof CMAP during propofol/nitrous oxide anaesthesia, but not duringisoflurane anaesthesia. A train of four magnetic stimuli ata frequency of 333 Hz is most effective in evoking potentialsfrom the upper and lower limb muscles. The authors concludethat rTCMS can be used for evaluation of the descending motorpathways during anaesthesia. Br J Anaesth 2003; 91: 487–92     

Clinical evaluation of double-burst stimulation Its relationship to train-of-four stimulation

Double-burst stimulation was compared with train-of-four stimulation in 23 adult patients receiving atracurium. Train-of-four was interrupted in 11 subjects every 2 minutes by one double-burst stimulation, and re-applied 6-30 seconds later; the height of the first double-burst response, compared with its control, was depressed slightly more than T1. The relationship between double-burst stimulation ratio and train-of-four ratio was indistinguishable from the line of identity. The train-of-four response, if repeated more than 12 seconds after double-burst stimulation, was not depressed compared with pre double-burst stimulation values. Fifteen anaesthetists were asked to detect fade manually in the second part of the study, while train-of-four was recorded on the opposite arm. One hundred and fourteen determinations were made in 12 patients. Fade was detected manually more often with double-burst stimulation than with TOF.     

Hypertrophy and Transformation of Muscle Fibers in Paraplegic Patients

Abstract: Transcutaneous electrical stimulation of the quadriceps femoris muscle was applied in 14 paraplegic patients (10 spastic patients with spinal cord lesions and 4 patients with conus-cauda lesions with denervation atrophy). In both the spastic and the denervated group, the vastus lateralis muscle was biopsied and computed tomography (CT) images of the entire upper leg were made both at the onset and termination of the 8-month training period. The stimulation was carried out twice a day for 20 min. The increase in muscle tissue was significant in the CT images. The biopsies showed that the fiber diameter of both fiber types increased during the training period in the spastic group from 47 to 67 μm and in the denervated group from 22 to 38 μm. In both groups, the differences were significant between the first and second biopsies. Both groups showed a marked Type 2 fiber predominance. The histological and CT findings correlated with the clinical improvement of muscle function.     

Validity of Single Tract Microelectrode Recording in Subthalamic Nucleus Stimulation

In surgery for subthalamic nucleus (STN) deep brain stimulation (DBS), precise implantation of the lead into the STN is essential. Physiological refinement with microelectrode recording (MER) is the gold standard for identifying STN. We studied single tract MER findings and surgical outcomes and verified our surgical method using single tract MER. The number of trajectories in MER and the final position of lead placement were retrospectively analyzed in 440 sides of STN DBS in 221 patients. Bilateral STN DBS yielded marked improvement in the motor score, dyskinesia/fluctuation score, and reduced requirement of dopaminergic medication in this series. The number of trajectories required to obtain sufficient activity of the STN was one in 79.0%, two in 18.2%, and three or more in 2.5% of 440 sides. In 92 sides requiring altered trajectory, the final direction of trajectory movement was posterior in 73.9%, anterior in 13.0%, lateral in 5.4%, and medial in 4.3%. In 18 patients, posterior moves were required due to significant brain shift with intracranial air caused by outflow of CSF during the second side procedure. Sufficient STN activity is obtained with minimum trajectories by proper targeting and precise interpretation of MER findings even in the single tract method. Anterior–posterior moves rather than medial–lateral moves should be attempted first in cases with insufficient recording of STN activity.     

青少年原发性肌张力障碍患者全身麻醉下行脑深部电刺激术麻醉体会1例

肌张力障碍是指主动肌与拮抗肌的收缩不协调或过度持续性收缩所引起的肢体扭曲、重复肌紧张动作或异常姿势为特征的锥体外系疾病。药物治疗无法缓解症状,脑深部电刺激术是治疗肌张力障碍疾病最为有效的治疗方法之一。该类患者因肌张力异常围手术期可能发生气道痉挛、反流误吸等并发症。此例患者为诊断原发性肌张力障碍的15岁青少年,在全身麻醉...     

Wireless Control of Functional Electrical Stimulation Systems

Abstract: With the assistance of crutches and functional electrical stimulation (FES), we are able to restore standing and simple gait in some spinal cord injured (SCI) patients. In present rehabilitative systems, the patient divides the gait cycle into stance and swing phases via pushbuttons mounted on the handles of the crutches, which are hardwired to the functional electrical stimulator. The surfacemount technology based telemetry system, which makes use of the radiofrequency medium at 40 MHz, was developed to provide wireless control of the FES system. Signals from crutch pushbuttons were coded and transferred from the transmitter to the receiver. The receiver was firmly attached to the patient's waist and was connected to the stimulator.