Spinal Cord Stimulation Group Research Articles

Spinal cord stimulation for failed back surgery syndrome: Outcomes in a workers’ compensation setting

Questions remain concerning effectiveness and risks of spinal cord stimulation (SCS) for chronic back and leg pain after spine surgery (“failed back surgery syndrome” [FBSS]). This prospective, population-based controlled cohort study evaluated outcomes of workers’ compensation recipients with FBSS who received at least a trial of SCS (SCS group, n = 51) versus those who (1) were evaluated at a multidisciplinary pain clinic and did not receive SCS (Pain Clinic, n = 39) or (2) received neither SCS nor pain clinic evaluation (Usual Care, n = 68). Patients completed measures of pain, function, medication use, and work status at baseline and 6, 12, and 24 months later. We also examined work time loss compensation over 24 months. Few (<10%) patients in any group achieved success at any follow-up on the composite primary outcome encompassing less than daily opioid use and improvement in leg pain and function. At 6 months, the SCS group showed modestly greater improvement in leg pain and function, but with higher rates of daily opioid use. These differences disappeared by 12 months. Patients who received a permanent spinal cord stimulator did not differ from patients who received some pain clinic treatment on the primary outcome at any follow-up (<10% successful in each group at each follow-up) and 19% had them removed within 18 months. Both trial and permanent SCS were associated with adverse events. In sum, we found no evidence for greater effectiveness of SCS versus alternative treatments in this patient population after 6 months.

Spinal Cord Stimulation Improves Ventricular Function and Reduces Ventricular Arrhythmias in a Canine Postinfarction Heart Failure Model

Spinal cord stimulation (SCS) reduces the incidence of ventricular tachyarrhythmias in experimental models. This study investigated the effects of long-term SCS on ventricular function in a postinfarction canine heart failure model. In stage 1, dogs underwent implantable cardioverter-defibrillator implantation and embolization of the left anterior descending artery followed by right ventricular pacing (240 ppm) for 3 weeks to produce heart failure. In stage 2, 28 surviving animals were assigned to the SCS (delivered at the T4/T5 spinal region for 2 hours 3 times a day), medicine (MED; carvedilol therapy at 12.5 mg PO BID), or control (CTRL; no therapy) group for the initial phase 1 study. In a subsequent phase 2 study, 32 stage 1 survivors were equally randomized to the SCS, MEDS (carvedilol plus ramipril 2.5 mg PO QD), SCS plus MEDS (concurrent therapy), or CTRL group. Animals were monitored for 5 weeks (phase 1) or 10 weeks (phase 2). In stage 3, all phase 1 animals underwent circumflex artery balloon occlusion for 1 hour. In the SCS group, left ventricular ejection fraction was 65+/-5% at baseline, 17+/-3% at the end of stage 1, and 47+/-7% at the end of stage 2. In the MED group, left ventricular ejection fraction was 61+/-4% at baseline, 18+/-3% at the end of stage 1, and 34+/-4% at the end of stage 2. In the CTRL group, left ventricular ejection fraction was 64+/-5% at baseline, 19+/-5% at the end of stage 1, and 28+/-3% at the end of stage 2. Left ventricular ejection fraction was significantly improved in the SCS compared with the MED and CTRL groups (P<0.001 for both). The mean number of spontaneous nonsustained ventricular tachyarrhythmias during stage 2 and the occurrence of ischemic ventricular tachyarrhythmias during stage 3 also were significantly decreased in the SCS (27+/-17 and 27%, respectively; P<0.03) and MED (58+/-42 and 33%; P<0.05) versus CTRL (88+/-52 and 76%) group. After 10 weeks in the phase 2 studies, the greatest recovery in ejection fraction was noted in the SCS (52+/-5%) and SCS+MEDS (46+/-4%) groups compared with the MEDS (38+/-2%) and CTRL (31+/-4%) groups. SCS significantly improved cardiac contractile function and decreased ventricular arrhythmias in canine heart failure.

Spinal cord stimulation induces c-Fos expression in the dorsal horn in rats with neuropathic pain after partial sciatic nerve injury

Spinal cord stimulation (SCS) is an established treatment for intractable neuropathic pain, especially CRPS-1. The mechanisms of action of SCS have only been partly elucidated and include suppression of the hyper-excitability of the Wide Dynamic Range neurons and a GABA increase in the dorsal horn. In the present study we demonstrate an increase of c-Fos immunoreactive cells in the dorsal horn after SCS, suggesting early cellular activation that may preclude earlier described electrophysiological and biochemical changes in the dorsal horn after SCS. In a rat model of neuropathic pain, allodynia was induced and quantified using the von Frey test. In 11 rats a SCS device was implanted and spinal cord stimulation performed. Withdrawal threshold were measured every 15 min up to 90 min. A sham group ( n = 6) also had a SCS device implanted, but did not receive SCS. After SCS the animals were perfused and histology was performed for quantification of c-Fos immunoreactivity in the dorsal horns. We found a significant increase in c-Fos in the SCS group compared to our sham group and control tissue, indicating late cellular activity in the dorsal horn after SCS.

Spinal cord stimulation for failed back surgery syndrome—does it work and is it cost-effective?

This Practice Point commentary discusses a study by Manca et al. that aimed to investigate the health-related quality-of-life and cost implications of spinal cord stimulation (SCS) plus nonsurgical conventional medical management (CMM) versus nonsurgical CMM alone. Manca et al. reported that the mean total 6-month health-care cost in the SCS group was significantly higher than that in the CMM alone group. However, the gain in health-related quality of life for patients undergoing SCS was significantly greater than that for patients undergoing CMM alone over this same period. In addition, patients in the SCS group used fewer analgesics and nondrug pain treatments (e.g. physical therapy), thus offsetting the upfront costs of SCS by 15%. The relevance of this study in providing an evaluation of health-care expenditures directed at treating low back pain relative to actual treatment outcomes is discussed.

Spinal cord stimulation versus conventional medical management for neuropathic pain: A multicentre randomised controlled trial in patients with failed back surgery syndrome

Patients with neuropathic pain secondary to failed back surgery syndrome (FBSS) typically experience persistent pain, disability, and reduced quality of life. We hypothesised that spinal cord stimulation (SCS) is an effective therapy in addition to conventional medical management (CMM) in this patient population. We randomised 100 FBSS patients with predominant leg pain of neuropathic radicular origin to receive spinal cord stimulation plus conventional medical management (SCS group) or conventional medical management alone (CMM group) for at least 6 months. The primary outcome was the proportion of patients achieving 50% or more pain relief in the legs. Secondary outcomes were improvement in back and leg pain, health-related quality of life, functional capacity, use of pain medication and non-drug pain treatment, level of patient satisfaction, and incidence of complications and adverse effects. Crossover after the 6-months visit was permitted, and all patients were followed up to 1 year. In the intention-to-treat analysis at 6 months, 24 SCS patients (48%) and 4 CMM patients (9%) ( p < 0.001) achieved the primary outcome. Compared with the CMM group, the SCS group experienced improved leg and back pain relief, quality of life, and functional capacity, as well as greater treatment satisfaction ( p ⩽ 0.05 for all comparisons). Between 6 and 12 months, 5 SCS patients crossed to CMM, and 32 CMM patients crossed to SCS. At 12 months, 27 SCS patients (32%) had experienced device-related complications. In selected patients with FBSS, SCS provides better pain relief and improves health-related quality of life and functional capacity compared with CMM alone.

Spinal cord stimulation for lower limb ischemic pain treatment

Spinal cord stimulation (SCS) was proposed many years ago for pain treatment but healing of ischemic ulcers opened a new treatment indication. The aim of this review was to assess the efficacy of SCS. studies regarding ischemic pain, limb ischemia and SCS reported on Pubmed have been reviewed, including randomized controlled trials (RCTs), clinical trials, Cochrane library review, neurophysiological studies and microcirculatory evaluations. Five RCTs, three multicenter studies and many clinical trials and reports of series have documented the clinical efficacy of SCS in the treatment of ischemic pain, particularly in patients with post-implantation increased blood flow. Pain relief, ulcer healing and limb salvage seems to be greater in non-diabetic patients, in diabetic without autonomic neuropathy, and in patients with rest pain or ulcer more than in patients with gangrene. A pain reduction of 75% was reported in the 3 RCTs; pain relief was significantly greater than in control group. Another study reported a lower use of analgesic in the SCS group. Moreover, pain relief obtained with SCS is maintained at follow-up while relief after medical treatment disappears quickly. The three multicenter studies showed a total pain relief between 41% and 43% and a cumulative pain reduction of 75% in 64.8% of cases. The clinical trials reported a pain reduction in up to 91% of patients. Based on six studies, the Cochrane reviewers found evidence to favor SCS over standard conservative treatment to improve limb salvage and clinical situation in patients with non-reconstructable critical limb ischemia (CLI). The mechanism of action of SCS is not completely clarified. the endovascular approach reduced the number of patients unsuitable for revascularization, however, some patients cannot be treated by angioplasty or open surgery; moreover, some are unfit for surgery, and others have persistent distal ischemia and pain with a functioning revascularization. In these cases SCS (alone or associated with prostanoids) can be indicated on the basis of the more recent evidences. A trial period with external stimulator, associated with a microcirculatory evaluation, is currently utilized to select patients that can derive benefit from this treatment, reducing costs.

An open label, single-centre, randomized trial of spinal cord stimulation vs. percutaneous myocardial laser revascularization in patients with refractory angina pectoris: the SPiRiT trial

Refractory angina pectoris leads to significant morbidity. Treatment options include percutaneous myocardial laser revascularization (PMR) and spinal cord stimulation (SCS). This study was designed to compare these two treatments. Subjects with Canadian Cardiovascular Society (CCS) class 3/4 angina and reversible perfusion defects were randomized to SCS (34) or PMR (34). The primary outcome was to compare exercise treadmill time on a modified Bruce protocol over 12 months. Thirty subjects in both groups completed 12-month follow-up. The mean total exercise time was 6.38 +/- 3.45 min in the SCS group and 7.41+/-3.68 min in the PMR group at baseline and 7.08 +/- 0.67 min in the SCS group and 7.12 +/-0.71 min in the PMR group at 12 months (95% confidence limits for the difference between the groups -1.02 to + 2.2 min, P = 0.466). There were no differences in angina-free exercise capacity, CCS class, and quality of life between treatments. SCS patients had more adverse events in the first 12 months, mainly angina or SCS system related (P = 0.001). There was little evidence of a difference in effectiveness between SCS and PMR in patients with refractory angina.

White Matter Disease in Magnetic Resonance Imaging Predicts Cerebral Complications After Coronary Artery Bypass Grafting

The aim of the present study was to assess neurologic and neuropsychologic complications in 104 patients randomized to coronary artery bypass grafting or spinal cord stimulation. An additional objective of the study was to assess whether preoperative white matter disease might predict cerebral complications, as previous studies have shown that there is a relationship between white matter disease and neuropsychologic decline after coronary artery bypass grafting. The patients were subjected to neurologic examination before and six months after intervention. The patients underwent a cerebral magnetic resonance imaging before intervention and the presence of white matter disease was related to development of cerebral complications. More patients in the bypass group than in the spinal cord stimulation group developed focal cerebral ischemia (p < 0.05) and astheno-emotional disorder (p < 0.001). More patients with white matter disease undergoing bypass were affected by focal cerebral ischemia (p < 0.01) and astheno-emotional disorder (p < 0.001) after the intervention compared to patients with white matter disease undergoing spinal cord stimulation. In patients with no white matter disease there were no differences between the bypass group and spinal cord stimulation group with regard to cerebral complications. Patients undergoing bypass had more neurologic and neuropsychologic complications than patients undergoing spinal cord stimulation. Furthermore, patients with white matter disease were affected by cerebral complications in a higher extent after bypass than after spinal cord stimulation. Thus, preoperative assessment of white matter disease before undergoing coronary artery bypass grafting might predict the patient's risk of developing cerebral injury.

Multiple Lead Spinal Cord Stimulation for Chronic Mechanical Low Back Pain: A Comparative Study with Intrathecal Opioid Drug Delivery

The objective of this paper is to assess the outcome of implanted multiple thoracolumbar lead spinal cord stimulation (SCS) in mechanical back pain without prior spinal surgery. These results are compared with intrathecal opioid drug delivery (ITDD). An anonymous third party patient questionnaire study of pain relief, function and psychosocial quality of life measures (recorded on 11-point numerical rating scales) for 12 patients with SCS and 13 with ITDD was used. Pain was significantly reduced with multiple lead SCS from a median of 9.0-6.5 (p<0.01) and with ITDD from a median of 8.5-5.5 (p<0.01). There was a trend towards greater reduction in pain in the ITDD group compared with the SCS group (pain differences 4.5 and 2.6, respectively) but this did not reach statistical significance. The majority of psychosocial quality of life measures were significantly more improved in the ITDD group compared with the SCS group (p<0.05). We conclude that multiple-lead SCS improves mechanical back pain in patients unresponsive to more conservative measures. However, ITDD provides significantly more improved quality of life measures, with a trend towards greater pain reduction than SCS.

Spinal cord stimulation for non-reconstructable chronic critical leg ischaemia.

Patients suffering from inoperable chronic critical leg ischaemia (NR-CCLI), face amputation of the leg. Spinal cord stimulation (SCS) has been proposed as a helpful treatment in addition to standard conservative treatment. To find evidence for an improvement of limb salvage, pain relief and clinical situation by means of SCS over conservative treatment alone. The reviewers searched the Cochrane Peripheral Vascular Diseases Group Specialised Register, (last searched November 2002), the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 4, 2002). Additional data were obtained from research institutes. Controlled studies comparing additional SCS with any form of conservative treatment in patients with NR-CCLI. Two reviewers (DU, HV), independently assessed the quality of the studies and extracted the data. Six studies comprising nearly 450 patients were included. In general the quality of the studies was good, although none of them was blinded due to the nature of the intervention. Limb salvage after 12 months was significantly higher in the SCS group (RR 0.71, 95%CI: 0.56 to 0.90; RD -0.13, 95%CI: -0.22 to -0.04). Significant pain relief occurred in both treatment groups, but was more prominent in the SCS group, in which the patients required significantly less analgesics. In the SCS group significantly more patients reached Fontaine stage II than in the conservative group (RR 4.9, 95%CI: 2.0 to 11.9; RD 0.33, 95%CI: 0.19 to 0.47). Overall, no significantly different effect on ulcer healing was observed between the two treatments. Complications of SCS treatment consisted of implantation problems (9%; 95%CI: 4 to 15%) and changes in stimulation requiring reintervention, (15%; 95%CI: 10 to 20%). Infections of the lead or pulse generator pocket occurred less frequently (3%; 95%CI: 0 to 6%). The overall risk of complications of additional SCS treatment was 17%, 95%CI: 12 to 22%, indicating a number needed to harm of six (95%CI: 5 to 8).A cost comparison was made in only one study. The average overall costs at two years were 36,500 euros, in the SCS group and 28,600 euros, in the conservative group. The difference (7,900 euros) was significant (p<0.009). There is evidence to favour SCS over standard conservative treatment to improve limb salvage and clinical situation in patients with NR-CCLI. The benefits of SCS against the possible harm of relatively mild complications, and costs must be considered.

Cost-Effectiveness of Spinal Cord Stimulation versus Coronary Artery Bypass Grafting in Patients with Severe Angina Pectoris – Long-Term Results from the ESBY Study

The present study is a 2-year follow-up of the 104 patients participating in the ESBY study (Electrical Stimulation versus Coronary Artery Bypass Surgery in Severe Angina Pectoris), a randomised prospective study including patients with increased surgical risk and no prognostic benefit from revascularisation. Hospital care costs, morbidity and causes of death after spinal cord stimulation (SCS) and coronary artery bypass grafting (CABG) were assessed, as well as the complication rate of SCS treatment. SCS proved to be a less expensive symptomatic treatment modality of angina pectoris than CABG (p < 0.01). The SCS group had fewer hospitalisation days related to the primary intervention (p < 0.0001) and fewer hospitalisation days due to cardiac events (p < 0.05). The groups did not differ with regard to causes of death. There were no serious complications related to the SCS treatment.

Spinal Cord Stimulation Prevents the Effects of Combined Experimental Ischemic and Traumatic Brain Injury

Spinal cord stimulation (SCS) interferes with cerebral blood flow (CBF). In this paper we try to evaluate the possible preventing effect of SCS in an animal model of combined ischemic and traumatic injury. We studied 20 New Zealand rabbits undergoing ligature of both carotid arteries and a right hemispheric craniectomy and about 3 h mechanical injury (200 mg) over the dura. In 10 animals (control group) SCS was not delivered; in 10 (SCS group) cervical SCS was started 20 min after arterial ligation and before the craniectomy and the mechanical injury. MR examination was performed in all the animals at the end of the experiments. Compared to the control group none but one of the SCS showed lesional pattern far from the craniectomy suggesting a ‘preventing’ effect of SCS on the secondary damage associated with our model combined ischemic and traumatic brain injury.

Nitric oxide synthase inhibition attenuates vasoactive response to spinal cord stimulation in an experimental cerebral vasospasm model.

The basic mechanism of delayed cerebral vasospasm following subarachnoid haemorrhage (SAH) has been intensively investigated. It is thought that nitric oxide (NO) is a basic mediator of the cerebral vasodilator mechanism. Previous clinical and experimental studies have shown a cerebral vasodilator effect of high cervical spinal cord stimulation (SCS) however, the mechanism of this effect is still controversial. We investigated the contribution of the vasodilator effect of NO to this mechanism in an experimental SAH model using rabbits. Four experimental groups, were designated: Group 1. Cerebral blood flow (CBF) was evaluated by transcranial Doppler ultrasonography (TDU) in 8 rabbits. Group 2. In 4 animals, intracisternal saline injection and cervical epidural electrode placement without SCS were performed before TDU. Group 3. TDU was performed before and after SCS on the fourth day of SAH in 8 rabbits. Group 4. In 8 animals, N-Nitro-L-Arginine Methyl Esther (L-NAME) was administered intracisternally on the fourth day of SAH, at a dose of 0.6 mg/kg, 45 minutes before SCS. CBF parameters, obtained via measurements or calculations from TDU data, were compared. The occurrence of vasospasm after SAH was demonstrated with significant changes in TDU parameters (high peak systolic velocity and positive values of the degree of stenosis). In all SAH animals, SCS resulted in significant vasodilation. Even after the injection of L-NAME, SCS still had a significant vasodilatory effect in SAH animals, but there was also a significant difference in CBF parameters in the SCS-only group when compared with the L-NAME treatment before SCS group. The mechanism of the cerebral vasodilatory effect of SCS remains controversial. Our results revealed the contribution of a neurohumoral effect which can be partially prevented by use of an NO synthase inhibitor.

Technical Data and Complications of Spinal Cord Stimulation: Data from a Randomized Trial on Critical Limb Ischemia

This study was done to evaluate the effect of spinal cord stimulation (SCS) on critical limb ischemia and to report technical problems and complications. One hundred and twenty patients with critical limb ischemia were eligible for randomization between medical treatment and medical treatment plus SCS. Sixty received a spinal cord stimulator (Itrel II; Medtronic, Minneapolis, Minn., USA). Primary outcome measures were limb salvage and pain relief. The mean pain reduction in both treatment groups was 50% (from 5 to 2.5 on the visual analog scale). The 2-year limb survival was 52% (SCS) versus 46% (standard treatment; p = 0.47). The number of patients undergoing major amputations in the SCS group with intermediate TcpO₂ values was half of that in the standard group (14 vs. 28; 24 vs. 48%; p = 0.17). Implantation was successful in 51 patients. Technical problems such as loss of stimulation due to lead displacement occurred in 13 patients (22%), local infection at the site of implantation occurred in 3 patients (5%), resulting in a total complication rate of 27%. Prematue depletion of the battery occurred within 2 years in 3 patients (5%). There were no lead fractures, epidural infections, hematoma or cerebrospinal fluid leakage. Training of physicians and better reliability of the hardware should reduce the frequency of technical problems. Lead displacement remains the major technical problem. The search for prognostic factors of limb salvage is important. One microcirculatory measurement (TcpO₂) seems to have a prognostic value, which remains to be described more precisely.

Neurosurgery (66)

Spinal cord stimulation in patients with chronic reflex sympathetic dystrophy. (Maastricht University Hospital, Maastricht, The Netherlands) N Engl J Med 2000;343:618–624.This randomized trial involved patients who had had reflex sympathetic dystrophy for at least 6 months. Thirty‐six patients were assigned to receive treatment with spinal cord stimulation plus physical therapy, and 18 were assigned to receive physical therapy alone. The spinal cord stimulator was implanted only if test stimulation was successful. The intensity of pain was assessed (on a visual‐analogue scale from 0 cm [no pain] to 10 cm [very severe pain]), as well as the global perceived effect (on a scale from 1 [worst ever] to 7 [best ever]), functional status, and the health‐related quality of life. The test stimulation of the spinal cord was successful in 24 patients; the other 12 patients did not receive implanted stimulators. In an intention‐to‐treat analysis, the group assigned to receive spinal cord stimulation plus physical therapy had a mean reduction of 2.4 cm in the intensity of pain at 6 months, as compared with an increase of 0.2 cm in the group assigned to receive physical therapy alone (P &lt; 0.001 for comparison between the 2 groups). In addition, the proportion of patients with a score of 6 (“much improved”) for the global perceived effect was much higher in the spinal cord stimulation group than in the control group (39% vs. 6%, P = 0.01). There was no clinically important improvement in functional status. The health‐related quality of life improved only in the 24 patients who actually underwent implantation of a spinal cord stimulator. Six of the 24 patients had complications that required additional procedures, including removal of the device in 1 patient. Conclude in carefully selected patients with chronic reflex sympathetic dystrophy, electrical stimulation of the spinal cord can reduce pain and improve health‐related quality of life. Conmment by R. Ruiz‐López, MD.This is a well‐written article describing a prospective, randomized, controlled trial of spinal cord stimulation (SCS) for reflex sympathetic dystrophy, which is also known as complex regional pain syndrome type I (CRPS I). The results show clearly that in carefully selected patients suffering from this pain syndrome, SCS can reduce pain and improve health‐related quality of life compared to patients treated only with physical therapy. Functional status did not improve in either group of patients as SCS treats pain, but not the disease itself. The authors note that the improvement in the overall score for health‐related quality of life was derived mainly from the alleviation of pain as in the study population, pain was the primary source of distress. This study represents a major reference for pain doctors and neurosurgeons treating CRPS and chronic pain.

Effects of Spinal Cord Stimulation and Coronary Artery Bypass Grafting on Myocardial Ischemia and Heart Rate Variability: Further Results from the ESBY Study

In the present study, 24-hour ECG recordings were analyzed from the Electrical Stimulation versus Coronary Artery Bypass Surgery (ESBY) Study where spinal cord stimulation was compared to CABG (coronary artery bypass grafting) in selected patients with severe angina pectoris. During the monitoring period, the spinal cord stimulation was discontinued to evaluate possible long-term effects of this treatment. The number of ischemic episodes and the duration of ischemia decreased in the CABG group at the follow-up when compared to spinal cord stimulation (p < 0.05). In spite of this, the number of anginal attacks decreased (p < 0.0001) in both groups. The fact that the anginal symptoms decreased in the spinal cord stimulation group in spite of discontinued stimulation and lack of effects on ischemic ST changes could indicate a long-term primary analgesic effect of this treatment in addition to the well-documented acute anti-ischemic effect.

Microcirculatory investigations to determine the effect of spinal cord stimulation for critical leg ischemia: The Dutch Multicenter Randomized Controlled Trial

Purpose: Patients with non-reconstructable critical limb ischemia generally undergo medical treatment only to prevent or postpone amputation. There is some evidence that spinal cord stimulation (SCS) stimulates ischemic wound healing. Thus, this could benefit limb survival through improved skin perfusion. We investigated the effect of SCS versus conservative treatment on skin microcirculation in relation to treatment outcome in patients with non-reconstructable critical limb ischemia. Methods : Standard medical treatment plus SCS was compared with only standard medical treatment in a multicenter randomized controlled trial comprised of 120 patients with surgically non-reconstructable chronic rest pain or ulceration. We investigated skin microcirculation by means of capillary microscopy, laser Doppler perfusion, and transcutaneous oxygen measurements in the foot. The microcirculatory status just before treatment was classified in three categories (poor, intermediate, and good) and was related to limb survival after a minimum follow-up period of 18 months. Results : Clinical parameters, peripheral blood pressures, and limb survival rates showed no significant differences between the SCS and standard groups during the follow-up period. In both treatment groups, amputation frequency after 18 months was high in patients with an initially poor microcirculatory skin perfusion (SCS 80% vs standard treatment 71%; NS) and low in those with a good skin perfusion (29% vs 11 %, respectively; NS). In patients with an intermediate skin microcirculation amputation, frequency was twice as low in patients additionally treated with SCS as in the standard treatment group (48% vs 24%; P = .08). In these patients, microcirculatory reactive hyperemia during the follow-up period reduced in the standard group but not in the SCS group ( P < .01). Conclusion: Selection on the basis of the initial microcirculatory skin perfusion identifies patients in whom SCS can improve local skin perfusion and limb survival. (J Vasc Surg 1999;30:236-44.)

Spinal-cord stimulation in critical limb ischaemia: a randomised trial

For patients with critical limb ischaemia, spinal-cord stimulation has been advocated for the treatment of ischaemic pain and the prevention of amputation. We compared the efficacy of the addition of spinal-cord stimulation to best medical treatment in a randomised controlled trial. 120 patients with critical limb ischaemia not suitable for vascular reconstruction were randomly assigned either spinal-cord stimulation in addition to best medical treatment or best medical treatment alone. Primary outcomes were mortality and amputation. The primary endpoint was limb survival at 2 years. The mean (SD) age of the patients was 72.6 years (10.3). Median (IQR) follow-up was 605 days (244-1171). 40 (67%) of 60 patients in the spinal-cord-stimulator group and 41 (68%) of 60 patients in the standard group were alive at the end of the study, (p=0.96). There were 25 major amputations in the spinal-cord-stimulator group and 29 in the standard group, (p=0.47). The hazard ratio for survival at 2 years without major amputation in the spinal-cord stimulation group compared with the standard group was 0.96 (95% CI 0.61-1.51). Spinal-cord-stimulation in addition to best medical care does not prevent amputation in patients with critical limb ischaemia.

Preemptive spinal cord stimulation reduces ischemia in an animal model of vasospasm.

Spinal cord stimulation (SCS) has been increasingly used in the treatment of ischemia caused by obliterative diseases in the extremities and in the cardiac circulation. The most promising effects have been obtained when physicians suspect that a major vasospastic component underlies the ischemic symptoms (e.g., as in Raynaud's disease). Despite the clinical success of this treatment method, little is known about the mechanisms underlying the pain relief it produces and its anti-ischemic effects. Most earlier experimental studies have used normal animals or animals with cerebral vasospasm induced by injection of autologal blood into the cerebrospinal fluid space. In the present study, we applied SCS in a rat model via implanted electrodes to study the effect of preemptive stimulation on the ischemia caused by vasospasm in a neurovascular flap in the groin; the vasospasm was induced by mechanical pressure applied to the feeding artery. In rats treated with SCS, delivered with parameters similar to those used clinically, the percentage of flaps recovering normal microcirculation after the spasm was significantly higher than in the untreated control group (100 and 28%, respectively; P < 0.05), and the maximal blood flow after the ischemic episode was significantly higher in the SCS group than in the control group (127 and 51 arbitrary units, respectively; P < 0.05). The percentage of animals regaining the premanipulation circulation after the provocation of a second spasm was also greater in the SCS-treated group than in the control animals (50 and 14%, respectively; P < 0.05). Pilot studies showed that this protective effect was specific to SCS given before spasm induction, an observation corroborated by clinical experiences.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of spinal cord stimulation (SCS) in patients with inoperable severe lower limb ischaemia: A prospective randomised controlled study

This study was designed to test the hypothesis that spinal cord stimulation (SCS) improves limb salvage in patients with inoperable severe leg ischaemia. Prospective randomised controlled study with 18 months follow-up. Vascular surgical units in two university hospitals. Atherosclerotic (n = 41) and diabetic (n = 10) patients having chronic leg ischaemia with rest pain and/or ischaemic ulcerations due to technically inoperable arterial occlusions. Limb salvage and amount of tissue loss within 18 months, pain relief. Twenty-five patients were randomized to SCS and 26 to analgesic (control) treatment. Macrocirculatory parameters were not different in the two groups during follow-up. Long-term pain relief was observed only in the SCS group. At 18 months, limb salvage rates in the SCS and control groups were 62% and 45% (N.S.). Tissue loss was less (p = 0.05) in the SCS group. A subgroup analysis of patients without arterial hypertension showed a significantly lower amputation rate in the SCS vs the control group. SCS provided long-term pain relief but limb salvage at 18 months was not significantly improved by SCS in this rather small study. The results suggest that SCS may reduce amputation levels in patients with severe inoperable leg ischaemia and be most effective in patients without arterial hypertension.