Spine 2002 Nov 15;27(22):2614-9; discussion 2620

Epidural Spinal Cord Stimulation (Dorsal Column Stimulation) Outcome Studies

Chronic pain of spinal origin: the costs of intervention. Spine 2002 Nov 15;27(22):2614-9; discussion 2620

Straus BN.

North Georgia Pain Clinic, Canton, Georgia 30114, USA. NGPCDHS@aol.com

The cost of chronic benign spinal pain is large and growing. The costs of interventional treatment for spinal pain were at a minimum of $13 billion (U.S. dollars) in 1990, and the costs are growing at least 7% per year. Medical treatment of chronic pain costs $9000 to $19,000 per person per year. The costs of interventional therapy is calculated. Methods of evaluating differential treatments in terms of costs are described. Cost-minimization versus cost-effectiveness approaches are described. Spinal cord stimulation and intraspinal drug infusion systems are alternatives that can be justified on a cost basis. Cost minimization analysis suggests that epidural injections under fluoroscopy may not be justified by the current literature.

Treatment of chronic pain with spinal cord stimulation versus alternative therapies: cost-effectiveness analysis. Neurosurgery 2002 Jul;51(1):106-15; discussion 115-6

Kumar K, Malik S, Demeria D.

Department of Surgery, Regina General Hospital, University of Saskatchewan, Canada. K.Kumar@sk.sympatico.ca

OBJECTIVE: There is limited available research measuring the cost-effectiveness of spinal cord stimulation (SCS), compared with best medical treatment/conventional pain therapy (CPT). The purpose of this study was to tabulate the actual costs (in Canadian dollars) for a consecutive series of patients treated with SCS in a constant health care delivery environment and to compare the costs with those for a control group treated in the same controlled environment. METHODS: We present a consecutive series of 104 patients with failed back syndrome. Within this group, 60 patients underwent SCS electrode implantation, whereas 44 patients were designated as control subjects. We monitored these patients for a 5-year period and tabulated the actual costs incurred in diagnostic imaging, professional fees paid to physicians, implantation (including the costs for hardware), nursing visits for maintenance of the stimulators, physiotherapy, chiropractic treatments, massage therapy, and hospitalization for treatment of breakthrough pain. From these data, the cumulative costs for each group were calculated for a 5-year period. An analysis of Oswestry questionnaire results was also performed, to evaluate the effects of treatment on the quality of life. RESULTS: The actual mean cumulative cost for SCS therapy for a 5-year period was $29,123/patient, compared with $38,029 for CPT. The cost of treatment for the SCS group was greater than that for the CPT group in the first 2.5 years. The costs of treating patients with SCS became less than those for CPT after that period and remained so during the rest of the follow-up period. In addition, 15% of SCS-treated patients were able to return to employment, because of superior pain control and lower drug intake. No patients in the control group were able to return to employment of any kind. CONCLUSION: SCS is cost-effective in the long term, despite the initial high costs of the implantable devices.

Cost-effectiveness analysis of spinal cord stimulation in treatment of failed back surgery syndrome. J Pain Symptom Manage 1997 May;13(5):286-95

Bell GK, Kidd D, North RB.

Charles River Associates Incorporated, Boston, MA, USA.

This article presents an analysis of the medical costs of spinal cord stimulation (SCS) therapy in the treatment of patients with failed back surgery syndrome (FBSS). We compared the medical costs of SCS therapy with an alternative regimen of surgeries and other interventions. Externally powered (external) and fully internalized (internal) SCS systems were considered separately. Clinical management models of each of the therapy alternatives were derived from the clinical literature, retrospective data sets, expert opinion, and published diagnostic and therapy protocols. No value was placed on pain relief or improvements in the quality of life that successful SCS therapy can generate. We found that by reducing the demand for medical care by FBSS patients, SCS therapy can lower medical costs. On average, given current screening and efficacy rates, SCS therapy pays for itself within 5.5 years. For those patients for whom SCS therapy is clinically efficacious, the therapy pays for itself within 2.1 years.

Economic evaluation of spinal cord stimulation for chronic reflex sympathetic dystrophy. Neurology 2002 Oct 22;59(8):1203-9

Kemler MA, Furnee CA.

Department of Surgery, Maastricht University Hospital, Maastricht, The Netherlands. kemlerm@mzh.nl

OBJECTIVE: To evaluate the economic aspects of treatment of chronic reflex sympathetic dystrophy (RSD) with spinal cord stimulation (SCS), using outcomes and costs of care before and after the start of treatment. METHODS: Fifty-four patients with chronic RSD were randomized to receive either SCS together with physical therapy (SCS+PT; n = 36) or physical therapy alone (PT; n = 18). Twenty-four SCS+PT patients responded positively to trial stimulation and underwent SCS implantation. During 12 months of follow-up, costs (routine RSD costs, SCS costs, out-of-pocket costs) and effects (pain relief by visual analogue scale, health-related quality of life [HRQL] improvement by EQ-5D) were assessed in both groups. Analyses were carried out up to 1 year and up to the expected time of death. RESULTS: SCS was both more effective and less costly than the standard treatment protocol. As a result of high initial costs of SCS, in the first year, the treatment per patient is $4,000 more than control therapy. However, in the lifetime analysis, SCS per patient is $60,000 cheaper than control therapy. In addition, at 12 months, SCS resulted in pain relief (SCS+PT [-2.7] vs PT [0.4] [p < 0.001]) and improved HRQL (SCS+PT [0.22] vs PT [0.03] [p = 0.004]). CONCLUSIONS: The authors found SCS to be both more effective and less expensive as compared with the standard treatment protocol for chronic RSD.

Spinal cord stimulation in Belgium: a nation-wide survey on the incidence, indications and therapeutic efficacy by the health insurer. Pain 1994 Feb;56(2):211-6

Kupers RC, Van den Oever R, Van Houdenhove B, Vanmechelen W, Hepp B, Nuttin B, Gybels JM.

Department of Brain and Behaviour Research, Gasthuisberg, University of Leuven, Belgium.

The present report describes a nation-wide survey on the incidence, the indications and the efficacy of spinal cord stimulation (SCS), as assessed by the Belgian health authorities. The direct motive for this survey was the rapidly growing expenditures resulting from the increasing use of SCS. Between 1983 and 1992, nearly 700 SCS devices were implanted for a population of less than 10 million inhabitants. The most common indication for SCS was failed back survey (61.4%). Whereas SCS was initially only performed in university teaching hospitals, it is now also widely practiced in general hospitals. In 3 studies, the efficacy of SCS was assessed. In a first study, success was defined in terms of resumption of professional activities. After a mean follow-up of more than 1 year, less than 5% of the 147 patients treated with SCS had returned to work. A second study investigated the subjective evaluation of the therapy by the patient. Seventy patients with a mean follow-up of 3.5 years were studied. In 52% of the patients, the effect of SCS was judged as good to very good. Men scored better than women. In addition, the results obtained in the teaching hospitals were significantly better than those obtained in general hospitals. In a third study, the impact of psychiatric screening on patient selection was evaluated. Of the 100 candidates, 36 were withheld from implantation with a SCS device because of psychiatric contra-indications. Patients who had received a positive psychiatric advice showed a significantly better therapeutic outcome than patients for whom the psychiatrist had made reservations.

Spinal cord stimulation: a valuable treatment for chronic failed back surgery patients. J Pain Symptom Manage 1997 May;13(5):296-301

Devulder J, De Laat M, Van Bastelaere M, Rolly G.

Department of Anesthesia-Section Pain Clinic, University Hospital of Gent, Belgium.

Spinal cord stimulation (SCS) has been used in the treatment of "chronic failed back surgery syndrome" for many years. To evaluate long-term results and cost effectiveness of SCS, we interviewed 69 patients treated during a period of 13 years. Twenty-six patients stopped using SCS; there was no clear explanation for this unsatisfactory result in 10. Forty-three patients continued with the therapy and obtained good pain relief. Electrode breakage either spontaneous or due to a procedure to obtain better stimulation paresthesias was more frequent in the radiofrequency-coupled system group than in the battery group (mean +/- SEM 2.81 +/- 2.0 versus 1.42 +/- 1.51, respectively; P = 0.0018). Ten patients obtained better pain relief than during the trial procedure. Some still need opioid analgesics, but 11 of the 16 who require these drugs obtained a synergistic effect when concomitantly using the stimulator. Eleven patients have returned to work. In our center, the application of SCS costs on average $3660 per patient per year. Although this seems expensive, it may be a cost-effective treatment if other therapies fail.

Spinal cord stimulation inhibits long-term potentiation of spinal wide dynamic range neurons. Brain Res 2003 May 23;973(1):39-43

Wallin J, Fiska A, Tjolsen A, Linderoth B, Hole K.

Department of Clinical Neuroscience, Section of Neurosurgery, Karolinska Institutet/Hospital, SE-171 76, Stockholm, Sweden

It has been suggested that long-term potentiation (LTP) of dorsal horn neurons is a phenomenon that contributes to the development of chronic neuropathic pain. Spinal cord stimulation (SCS) may be an effective tool in alleviating such pain. The aim of this electrophysiological study in rats was to examine if SCS suppresses LTP of dorsal horn wide dynamic range (WDR) neurons. Increased knowledge of the mechanisms behind the effects of SCS may facilitate its further advancement and improve clinical efficacy. As previously shown, intensive, high-frequency electrical stimulation of the sciatic nerve in the rat induces an increased firing response of WDR neurons. Here we report that SCS gradually reduced this increased C-fiber response back to the baseline level. However, A-fiber responses were neither potentiated by the conditioning stimulus used nor were they affected by SCS. These data suggest that SCS affects the C-fiber component of dorsal horn central sensitization, which is noteworthy since SCS, based on previous studies, is believed to primarily influence A-fiber functions.

Implantable devices for pain control: spinal cord stimulation and intrathecal therapies. Best Pract Res Clin Anaesthesiol 2002 Dec;16(4):619-49

Krames E.

Pacific Pain Treatment Centers and Neuromodulation, Journal of the International Neuromodulation Society, San Francisco, California 94109, USA.

Untreated chronic pain is costly to society and to the individual suffering from it. The treatment of chronic pain, a multidimensional disease, should rely on the expertise of varying health care providers and should focus not only on the neurobiological mechanisms of the process but also on the psychosocial aspects of the disease. Implantable devices are costly and invasive, and such efficacious therapies should be used only when more conservative and less costly therapies have failed to provide relief of pain and suffering. Spinal cord stimulation provides neuromodulation of neuropathic, but not nociceptive, pain signals and when used for appropriate indications in the right individuals provides approximately 60-80% long-term pain relief in 60-80% of patients trialled for efficacy. Intrathecal therapies with opioids such as morphine, fentanyl, sufentanil or meperidine--or non-opioids such as clonidine or bupivacaine--provide analgesia in patients with nociceptive or neuropathic pain syndromes. Baclofen, intrathecally, provides profound relief of muscle spasticity due to multiple sclerosis, spinal cord injuries, brain injuries or cerebral palsy.

A prospective, randomized study of spinal cord stimulation versus reoperation for failed back surgery syndrome: initial results. Stereotact Funct Neurosurg 1994;62(1-4):267-72

North RB, Kidd DH, Lee MS, Piantodosi S.

Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Md., USA.

Spinal cord stimulation (SCS) has been reported to be effective treatment for the failed back surgery syndrome in a number of retrospective case series. Its retrospectively reported results compare favorably with those of neurosurgical treatment alternatives, such as reoperation and ablative procedures. There has been no direct prospective comparison, however, between SCS and other techniques for pain management. We have undertaken a prospective, randomized comparison of SCS and reoperation in patients with persistent radicular pain, with and without low back pain, following lumboscral spine surgery. Patients selected for reoperation by standard criteria have been randomly assigned to initial treatment by one or the other technique. The primary outcome measure is the frequency of crossover to the alternative procedure, if the results of the first have been unsatisfactory after 6 months. Results for the first 27 patients reaching the 6-month crossover point show a statistically significant (p = 0.018) advantage for SCS over reoperation. This is one of many potentially important outcome measures, which are to be followed long-term as a larger overall study population accrues.

Spinal cord stimulation versus reoperation for failed back surgery syndrome: a prospective, randomized study design. Acta Neurochir Suppl (Wien) 1995;64:106-8

North RB, Kidd DH, Piantadosi S.

Department of Neurosurgery and Biostatistics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Retrospectively reported results of spinal cord stimulation compare favorably with those of neurosurgical treatment alternatives for the treatment of failed back surgery syndrome, including reoperation and ablative procedures. There has been no direct prospective comparison, however, between SCS and other techniques for pain management. Therefore, we have designed a prospective, randomized comparison of spinal cord stimulation and reoperation in patients with persistent radicular pain, with and without low back pain, after lumbosacral spine surgery. Patients selected for reoperation by standard criteria are randomly assigned to initial treatment by one or the other technique. The primary outcome measure is the frequency of crossover to the alternative procedure, if the results of the first have been unsatisfactory after 6 months. Results for the first 27 patients reaching the 6-month crossover point show a statistically significant (p = 0.018) advantage for spinal cord stimulation over reoperation. Many other potentially important outcome measures will now be followed long-term as a larger overall study population accumulates.

Failed back surgery syndrome: 5-year follow-up after spinal cord stimulator implantation. Neurosurgery 1991 May;28(5):692-9

North RB, Ewend MG, Lawton MT, Kidd DH, Piantadosi S.

Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Spinal cord stimulation, in use for more than 20 years, has evolved into an easily implemented technique, with percutaneous methods for electrode placement. We have reviewed our experience with this technique in treating "failed back surgery syndrome," and have assessed patient and treatment characteristics as predictors of long-term outcome. A series of 50 patients with failed back surgery syndrome (averaging 3.1 previous operations), who underwent spinal cord stimulator implantation, was interviewed by impartial third parties, at mean follow-up intervals of 2.2 years and 5.0 years. Successful outcome (at least 50% sustained relief of pain and patient satisfaction with the result) was recorded in 53% of patients at 2.2 years and in 47% of patients at 5.0 years postoperatively. Ten of 40 patients who were disabled preoperatively returned to work. Improvements in activities of daily living were recorded in most patients for most activities; loss of function was rare. Most patients reduced or eliminated analgesic intake. Statistical analysis (including univariate and multivariate logistic regression) of patient characteristics as prognostic factors showed significant advantages for female patients and for those with programmable multi-contact implanted devices. These results, in patients with postsurgical lumbar arachnoid and epidural fibrosis and without surgically remediable lesions, compare favorably with the results in two separate series of patients with failed back surgery syndrome, in whom 1) surgical lesions were diagnosed and repeated operation performed; and 2) monoradicular pain syndromes were diagnosed and dorsal root ganglionectomies performed at our institution. This suggests the need for further assessment of selection criteria, critical analysis of treatment outcome, and prospective study of spinal cord stimulation and alternative approaches to failed back surgery syndrome.

Economic evaluation of spinal cord stimulation for chronic reflex sympathetic dystrophy. Neurology. 2002 Oct 22;59(8):1203-9.

Kemler MA, Furnee CA.

Department of Surgery, Maastricht University Hospital, Maastricht, The Netherlands. kemlerm@mzh.nl

OBJECTIVE: To evaluate the economic aspects of treatment of chronic reflex sympathetic dystrophy (RSD) with spinal cord stimulation (SCS), using outcomes and costs of care before and after the start of treatment. METHODS: Fifty-four patients with chronic RSD were randomized to receive either SCS together with physical therapy (SCS+PT; n = 36) or physical therapy alone (PT; n = 18). Twenty-four SCS+PT patients responded positively to trial stimulation and underwent SCS implantation. During 12 months of follow-up, costs (routine RSD costs, SCS costs, out-of-pocket costs) and effects (pain relief by visual analogue scale, health-related quality of life [HRQL] improvement by EQ-5D) were assessed in both groups. Analyses were carried out up to 1 year and up to the expected time of death. RESULTS: SCS was both more effective and less costly than the standard treatment protocol. As a result of high initial costs of SCS, in the first year, the treatment per patient is $4,000 more than control therapy. However, in the lifetime analysis, SCS per patient is $60,000 cheaper than control therapy. In addition, at 12 months, SCS resulted in pain relief (SCS+PT [-2.7] vs PT [0.4] [p < 0.001]) and improved HRQL (SCS+PT [0.22] vs PT [0.03] [p = 0.004]). CONCLUSIONS: The authors found SCS to be both more effective and less expensive as compared with the standard treatment protocol for chronic RSD.

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Spinal cord stimulation in patients with chronic reflex sympathetic dystrophy. N Engl J Med. 2000 Aug 31;343(9):618-24.

Kemler MA, Barendse GA, van Kleef M, de Vet HC, Rijks CP, Furnee CA, van den Wildenberg FA.

Department of Surgery, Maastricht University Hospital, The Netherlands. mkeml@shee.azm.nl

BACKGROUND: Chronic reflex sympathetic dystrophy (also called the complex regional pain syndrome) is a painful, disabling disorder for which there is no proven treatment. In observational studies, spinal cord stimulation has reduced the pain associated with the disorder. METHODS: We performed a randomized trial involving patients who had had reflex sympathetic dystrophy for at least six 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 a test stimulation was successful. We assessed the intensity of pain (on a visual-analogue scale from 0 cm [no pain] to 10 cm [very severe pain]), the global perceived effect (on a scale from 1 [worst ever] to 7 [best ever]), functional status, and the health-related quality of life. RESULTS: 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 six months, as compared with an increase of 0.2 cm in the group assigned to receive physical therapy alone (P<0.001 for the comparison between the two 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 percent vs. 6 percent, 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. CONCLUSIONS: In carefully selected patients with chronic reflex sympathetic dystrophy, electrical stimulation of the spinal cord can reduce pain and improve the health-related quality of life.

Spinal cord stimulation--a long-term evaluation in patients with chronic pain. Br J Neurosurg. 2001 Aug;15(4):335-41.

Kay AD, McIntyre MD, Macrae WA, Varma TR.

Ninewells Hospital Medical School, Dundee, UK. adk4z@clinmed.gla.ac.uk

Spinal cord stimulation (SCS) is an established treatment modality for chronic pain, angina pectoris, and peripheral vascular disease. This study evaluates experience with SCS over a 13-year period with emphasis on surgical complications, revisions and pain relief. It took the form of a retrospective study of medical/surgical records coupled with a postal/telephone questionnaire. The subjects consisted of seventy patients, aged from 21 to 76 years (mean 47; median 46), with severe, chronic pain refractory to conventional treatment, who underwent SCS implantation between 1984 and 1997. It investigated surgical revisions, complications and pain relief. There were 72 surgical revisions comprising electrode replacement/repositioning (32), generator replacement (22), cable failure (6) and implant removal (12). Half the devices were revised within 3 years (95% confidence interval: 2-5 years) of implantation. Six (8.6%) implants became infected. Sixty per cent of patients reported substantial relief of pain. This study shows that the majority of patients undergoing SCS derive significant benefit in terms of pain relief, but commonly require surgical revisions due to both technical and biological factors. These devices require systematic evaluation to determine optimal usage, clinical effectiveness and cost-benefit analysis.

Ý[Spinal cord stimulation (SCS) using an 8-pole electrode and double-electrode system as minimally invasive therapy of the post-discotomy and post-fusion syndrome--prospective study results in 34 patients] Z Orthop Ihre Grenzgeb. 2002 Nov-Dec;140(6):626-31.

[Article in German]

Rutten S, Komp M, Godolias G.

Klinik fur Orthopadie am Lehrstuhl fur Radiologie und Mikrotherapie, Universitat Witten/Herdecke, Ressort Wirbelsaulenchirurgie und Schmerztherapie, St.-Anna-Hospital Herne, Deutschland, Germany. ruetten@orthopain.de

AIM: Therapy of a pronounced post-discotomy (PDS) and post-fusion syndrome (PFS) is often unsatisfactory because of the complexity and multifactorial pain genesis. If surgical interventions cannot promise relief and if the entire interdisciplinary spectrum of conservative treatment measures is inadequate, the area of neuromodulative procedures offers spinal cord stimulation (SCS). The objective of this study was to examine the therapeutic possibilities of SCS using an 8-pole electrode and double electrode system in PDS and PFS with extensive back-leg pain areas. METHOD: An appropriate SCS system was implanted in 34 patients with PDS and PFS. Follow-up examinations were made prospectively over a period of 24 months using general criteria and psychometric test measuring instruments validated for German-language use. RESULTS: An 8-pole double electrode system was implanted 23 times, a single electrode sufficed in 11 cases. The area of pain was covered in all patients. This required special technical capabilities of the SCS system. The results remained constant over 24 months. The morphine dose could be reduced by at least 50 %. All measuring instruments confirmed a clear reduction in pain and improvement in quality of life as a result of SCS implantation. CONCLUSION: The SCS is an minimally invasive surgical procedure which can enlarge the therapeutical possibilities of pronounced PDS and PFS resistant to other modes of treatment. Special technical possibilities of parameter setting are required to cover the pain areas.

Dorsal column stimulation (DCS): cost to benefit analysis. Acta Neurochir Suppl (Wien). 1991;52:121-3.

Bel S, Bauer BL.

Department of Neurosurgery, Philipps University of Marburg, Federal Republic of Germany.

In order to analyse the ratio of costs to clinical benefit of the implantation of a neurostimulator (type Medtronic SE-4) we examined a group of 14 patients who required treatment for chronic lumboischialgia after repeated surgery for herniated discs. Over a period of two years we evaluated the pre- and postimplantation costs. The implantation of a DC-Stimulator resulted in a striking decrease in drug requirements, in the total time of clinical treatment, and in the degree of disability. The DCS provides a satisfying method of treatment for chronic lumboischialgia after repeated surgery for herniated discs. Despite relatively high primary costs, treatment with a DCS results in a significant decrease in the accumulated expenses in comparison to other methods of medical treatment in similar cases.

Treatment of the failed back surgery syndrome due to lumbo-sacral epidural fibrosis. Acta Neurochir Suppl (Wien). 1995;64:116-8.

Fiume D, Sherkat S, Callovini GM, Parziale G, Gazzeri G.

Divisione di Neurochirurgia, Ospedale S. Filippo, Rome, Italy.

The failed back surgery syndrome (FBSS) is a severe, long-lasting, disabling and relatively frequent (5-10%) complication of lumbosacral spine surgery. Wrong level of surgery, inadequate surgical techniques, vertebral instability, recurrent disc herniation, and lumbo-sacral fibrosis are the most frequent causes of FBSS. The results after repeated surgery on recurrent disc herniations are comparable to those after the first intervention, whereas repeated surgery for fibrosis gives only 30-35% success rate, and 15-20% of the patients report worsening of the symptoms. Computerized tomography (CT) with contrast medium and, in particular, Gd-DPTA enhanced MRI have recently allowed a differentiation between these two pathologies permitting us to adopt different therapies. In 1982-92 we applied spinal cord stimulation (SCS) as a first therapy of FBSS with proven lumbo-sacral fibrosis. Fifty-five patients underwent percutaneous trial SCS with a mono/multipolar electrode placed at the level of Th9-12. In the 36 patients who had a positive response to the trial stimulation, the electrode was connected to an implantable neurostimulator. On January '94 a third party, not involved in the treatment of the patients, controlled 34 of the 36 patients with a mean follow-up of 55 months. We classified the patients reporting at least 50% pain relief and satisfaction with result as successful, and 56% of the patients fell in that category. 10 out of 34 patients were able to resume their work. The success rate was significantly higher in females (73%) than in males, and in radicular rather than axial pain. Our data have led us to consider SCS as a first choice treatment in FBSS due to lumbo-sacral fibrosis.

Long-term pain relief during spinal cord stimulation. The effect of patient selection. Qual Life Res. 1994 Feb;3(1):21-7.

Van de Kelft E, De La Porte C.

Department of Neurosurgery, Universitair Ziekenhuis Antwerpen, Edegem, Belgium.

We reviewed our experience with spinal cord stimulation (SCS) in treating 116 patients with pain in one or both legs. All these patients were selected for an initial week of trial stimulation by the criteria: pain due to a known benign organic cause, failure of conventional pain control methods and absence of major personality disorders. Selected patients included 78 with the Failed Back Surgery Syndrome (FBSS), in whom proven correlation existed between the clinical picture and the neuroradiological and electromyogram abnormalities. Eighty-four out of 116 selected patients underwent definitive SCS implantation after 1 week of trial stimulation with excellent results (more than 75% pain relief). They were followed clinically every 3 months for a mean follow-up period of 47 months. Forty-five patients (54%) continued to experience at least 50% of pain relief at the latest follow up. Seventy-seven patients (91%) were able to reduce their medication intake and 50 patients (60%) reported an improvement in lifestyle. FBSS patients responded more positively to the trial stimulation than the other patients. However, the later outcome was not affected by patient selection as long-term benefit was similar in all definitive SCS patients irrespective of etiology.