Long-Term Outcomes of Spinal Cord Stimulation With Paddle Leads in the Treatment of Complex Regional Pain Syndrome and Failed Back Surgery Syndrome

Introduction: Spinal cord stimulation (SCS) is frequently used to treat chronic, intractable back, and leg pain. Implantation can be accomplished with percutaneous leads or paddle leads. Although there is an extensive literature on SCS, the long‐term efficacy, particularly with paddle leads, remains poorly defined. Outcome measure choice is important when defining therapeutic efficacy for chronic pain. Numerical rating scales such as the NRS‐11 remain the most common outcome measure in the literature, although they may not accurately correlate with quality of life improvements and overall satisfaction. Methods: We reviewed the medical records of patients with failed back surgery syndrome (FBSS) or complex regional pain syndrome (CRPS) implanted with SCS systems using paddle leads between 1997 and 2008 at the Cleveland Clinic with a minimum six‐month follow‐up. Patients were contacted to fill out a questionnaire evaluating outcomes with the NRS‐11 as well as overall satisfaction. Results: A total of 35 eligible patients chose to participate. More than 50% of the patients with CRPS reported greater than 50% pain relief at a mean follow‐up of 4.4 years. Approximately 30% of the FBSS patients reported a 50% or greater improvement at a mean follow‐up of 3.8 years. However, 77.8% of patients with CRPS and 70.6% of patients with FBSS indicated that they would undergo SCS surgery again for the same outcome. Conclusion: Patients with CRPS and FBSS have a high degree of satisfaction, indexed as willingness to undergo the same procedure again for the same outcome at a mean follow‐up of approximately four years. The percentage of satisfaction with the SCS system is disproportionally greater than the percentage of patients reporting 50% pain relief, particularly among patients with FBSS. This suggests that the visual analog scale may not be the optimal measure to evaluate long‐term outcomes in this patient population.     

Spinal Cord Stimulation With Hybrid Lead Relieves Pain in Low Back and Legs

Objective: The failed back surgery syndrome (FBSS) is the most common chronic pain syndrome. Whereas it is relatively easy to achieve pain relief in the lower limbs of FBSS patients with spinal cord stimulation (SCS), it is difficult to manage low back pain with SCS. The performance of a paddle‐shaped SCS lead that can be inserted surgically as well as percutaneously (a hybrid lead) was evaluated in a prospective study on the relief of low back pain and leg pain in patients with FBSS. Materials and Methods: Patients with FBSS being eligible for SCS were enrolled in the study, and a hybrid lead was placed surgically. Outcome measures included pain scores for low back and leg pain assessed by visual analog scale (VAS), pain medication, and patient satisfaction. These scores were assessed before and at regular intervals after implantation. Results: It was shown that a single hybrid lead, generally positioned over the physiological midline of the spinal cord, is capable of alleviating both low back and leg pain in patients with FBSS. Forty‐five subjects were eligible for SCS and received trial stimulation. Forty‐two of them had a successful trial period and were converted to a permanent system. Their average VAS score at baseline was 8.0 for lower limb pain and 7.5 for low back pain. After six months of SCS, these average VAS scores were reduced to 3.2 and 3.5, respectively, and also pain medication was reduced significantly. Conclusion: SCS with a hybrid lead in subjects with FBSS is safe, and causes significant pain relief in both the low back and the lower limbs.     

脊髓电刺激治疗复杂区域性疼痛综合征

目的探讨脊髓电刺激术（spinal cord stimulation,SCS）治疗复杂性区域性疼痛综合征（complex regional pain syndrome,CRPS）的有效性。方法回顾性分析4例CRPS病例,其均经脊髓电刺激手术治疗并随访1年以上,采用视觉模拟疼痛评分（VAS）评估疼痛转归。结果病人术后VAS评分平均降低5．4,3例病人疼痛缓解大于50％,无手术并发症。结论SCS能够安全、有效地治疗CRPS。、     

Subcutaneous Stimulation as an Additional Therapy to Spinal Cord Stimulation for the Treatment of Lower Limb Pain and/or Back Pain: A Feasibility Study

Objective: The objective of this study was to demonstrate the efficacy of subcutaneous stimulation (SubQ) as an additional therapy in patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) was unsuccessful in treating low back pain. Study Design: Case series. Materials and Methods: FBSS patients with chronic limb and/or low back pain whose conventional therapies had failed received a combination of SCS (8‐contact Octad lead) and/or SubQ (4‐contact Quad Plus lead(s)). Initially leads were placed in the epidural space for SCS for a trial stimulation to assess response to suppression of limb and low back pain. Where SCS alone was insufficient in treating lower back pain, leads were placed superficially in the subcutaneous tissue of the lower back, directly in the middle of the pain area. A pulse generator was implanted if patients reported more than 50% pain relief during the trial period. Pain intensity for limb and lower back pain was scored separately, using visual analog scale (VAS). Pain and Quebec Back Pain Disability Scale (QBPDS) after 12‐month treatment were compared with pain and QBPDS at baseline. Results: Eleven FBSS patients, five male and six female (age: 51 ± 8 years; mean ± SD), in whom SCS alone was insufficient in treating lower back pain, were included. In nine cases, SubQ was used in combination with SCS to treat chronic lower back and lower extremity pain. In two cases only SubQ was used to treat lower back pain. SCS significantly reduced limb pain after 12 months (VAS_bl: 62 ± 14 vs. VAS_12m: 20 ± 11; p= 0.001, N= 8). SubQ stimulation significantly reduced low back pain after 12 months (VAS_bl: 62 ± 13.0 vs. VAS_12m: 32 ± 16; p= 0.0002, N= 10). Overall pain medication was reduced by more than 70%. QBPDS improved from 61 ± 15 to 49 ± 12 (p= 0.046, N= 10). Furthermore, we observed that two patients returned to work. Conclusion: SubQ may be an effective additional treatment for chronic low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms.     

Spinal cord stimulation for neuropathic pain

Spinal cord stimulation (SCS) is used for more than 40 years to treat localized chronic medically refractory neuropathic pain involving limb(s) and trunk. The most frequent indications remain complex regional pain syndrome (CRPS) failed back surgery syndrome (FBSS), and peripheral neuropathy. Stimulation-induced paresthesias, perceived by the patient, prevent blinded evaluation and increase the placebo effect, decreasing the credibility of the tonic SCS efficacy. Retrospective studies reported that about 50% of the patients are improved more than 50% at short-term, but long-term improvement is less. Several comparative randomized trials (RCT) are now available. In CRPS, a RCT demonstrated the superiority of SCS plus physiotherapy compared to physiotherapy alone. In FBSS, two RCTs have shown that SCS was superior to reoperation and conventional medical treatment, (CMM) respectively. New stimulation waveforms, namely burst, high frequency (10 KHz) stimulation and close-loop SCS, have been proposed recently to avoid the perception of paresthesias and/or increase the pain relief. RCTs in FBSS have suggested that these new SCS modalities were as least as efficient than conventional tonic SCS and perhaps slightly superior. Two RCTs confirmed SCS efficacy in painful diabetic neuropathy in comparison with CMM. Complications are frequent (hardware dysfunction or migration, superficial infection) but exceptionally serious. Consequently, the risk/benefit ratio is favorable to SCS, considering that chronic pain patients undergoing this procedure are usually resistant to all the other therapies.     

Spinal Cord Stimulation for Failed Back Surgery Syndrome

Objective. The purpose of this study is to evaluate the effectiveness of modern spinal cord stimulation (SCS) for the treatment of failed back surgery syndrome (FBSS). Materials and Methods. Thirty patients were treated with SCS between December 1992 and January 1998 for low back and radicular pain after multiple failed back surgeries. Permanent systems were implanted if trial stimulation led to > 50% pain reduction. Median long‐term follow‐up was 34 months (range, 6–66 months). Severity of pain was determined postoperatively by a disinterested third party. Results. Overall, 12 of the 16 patients (75%) who received permanent implants continued to report at least 50% relief of pain at follow‐up. All six patients who underwent placement of laminectomy‐styled electrode for SCS in the thoracic region had > 50% pain relief at long‐term follow‐up. Visual analog scores decreased an average of 3.2 (from 8.6 preoperatively to 5.4 postoperatively). Patients undergoing SCS placement via laminectomy in the thoracic region experienced an average decrease of 4.9 in VAS, whereas those who underwent percutaneous placement of thoracic leads had an average decrease of 2.5. Conclusions. SCS is an effective treatment for chronic low back and lower extremity pain which is refractory to conservative therapy and which is not amenable to corrective anatomic surgery. Though our patient population is small, our results imply that the laminectomy‐style electrodes in the thoracic region achieve better long‐term effectiveness than percutaneous leads.     

Neuropathic Limb Pain and Spinal Cord Stimulation: Results of the Dutch Prospective Study

Baseline and 12‐month follow‐up data from a prospective controlled study on patients treated with SCS for neuropathic limb pain (NLP) are analyzed critically. The outcome on pain, use of medication, and quality of life are reported and compared with the literature. Patients enrolled from April 1999 to December 2001 were part of a quality system study by the Dutch Working Group on Neuromodulation. In two years, more than 400 patients were admitted for several indications of chronic neuropathic pain. Failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) were the largest cohorts. FBSS was defined as persistent limb pain with/or without concomitant minor back pain after prior surgery for a slipped lumbar disc or spinal instability. SCS was a last resort therapy. Two criteria were used for eligibility: a SCL‐90 score below 225 and a mean visual analog score (VAS) of four days according to Jensen of ≥ 5. One hundred sixty nine patients were registered for FBSS. Thirty four did not fulfill the eligibility criteria, and 135 received several questionnaires for baseline evaluation. Thirty patients did not have successful trial stimulation (< 50% pain relief), leaving 105 patients for implantation. The mean scores of the baseline evaluation were: SCL 137 (SD 28.3) and VAS 7.3 (SD 1.2), McGill pain questionnaire (MPQ) total PRI: 22.4 (9.4), Sickness Impact Profile (SIP) total score: 19.4 (SD10.1), ROLAND disability (RD) 16.9 (SD 3.5) and EUROQOL (EQ‐5D) 55.2 (SD 14.5) (simple linear index). Medication quantification scale at intake was 11.5 (SD 7.9). 56.2% of the patients used one or more narcotic drugs at intake. 82% of the patients did not have a paid job at the time of inclusion. 61% of the patients lost their job due to their medical problems. Scores at 12‐m follow‐up were VAS 3.0 (SD 2.4), MPQ 10.8 (SD 8), SIP 11.7 (SD 9.4), EQ‐5D 38.2 (SD 19.2) and RD 12.4 (SD 4.8). The difference between baseline and 12‐m follow‐up is statistically significant for all measures. We conclude that the outcome measures indicate that SCS significantly reduces pain and enhances quality of life in patients having NLP not responding to other adjuvant therapy. Recommendations are proposed to make studies more comparable.     

Spinal Cord Stimulation vs. Conventional Medical Management: A Prospective,Randomized, Controlled,Multicenter Study of Patients with Failed Back Surgery Syndrome (PROCESS Study)

Introduction. Since its first application in 1967, numerous case series indicate that spinal cord stimulation (SCS) is an effective treatment for the management of failed back surgery syndrome (FBSS). However, only one randomized controlled trial has demonstrated that SCS provides more effective pain relief than re‐operation and conventional medical management. The PROCESS randomized, controlled, multicenter trial aims to assess the clinical effectiveness and cost‐effectiveness of SCS when added to conventional medical management compared to conventional medical management alone in patients with FBSS. Methods/Design. A total of 100 FBSS patients with predominantly neuropathic leg pain will be recruited from 12 centers and randomized to receive either conventional medical management alone or in combination with SCS for a period of 24 months. Patients will be evaluated at 1, 3, 6, 9, 12, 18, and 24 months. At the 6‐month visit, patients will be classified as successful (≥  50% pain relief in the legs) or unsuccessful (< 50% pain relief in the legs). If the results of the randomized treatment are unsuccessful, patients can cross over to the alternative treatment arm. Discussion. This paper highlights the rationale, design, methods, and challenges of an ongoing prospective, randomized, controlled, multicenter clinical trial that has been undertaken to obtain conclusive evidence of the clinical efficacy and cost‐effectiveness of an SCS system in patients with FBSS.     

Experiences From the Patient Perspective on Spinal Cord Stimulation for Failed Back Surgery Syndrome: A Qualitatively Driven Mixed Method Analysis

IntroductionWhen neither pharmacological therapies nor alternative interventions provide sufficient pain relief, spinal cord stimulation (SCS) can be used to treat Failed Back Surgery Syndrome (FBSS). Although it seems reasonable that quality of life (QoL)- and psychosocial-related factors contribute to the outcome of SCS since pain is a multidimensional experience, few qualitative studies have explored the expectations of SCS and experiences on SCS to treat FBSS from the patient perspective.ObjectivesThe aim of this study was to qualitatively and quantitatively map the FBSS patients’ experiences with SCS and the effects of SCS on low back pain caused by FBSS.Materials and MethodsA qualitative study with in-depth semi-structured interviews, assisted by the Brief Pain Inventory (BPI)-questionnaire.ResultsSeven themes regarding patients’ experiences, subdivided into 15 categories, were identified, including an understudied theme within this field of research, Spiritual Well-Being. “Acceptance” and “coping” emerged as pre-eminent motifs throughout these themes. Moreover, the realization of patients’ expectations were variable throughout the presented themes. According to the BPI Questionnaire, four out of 13 patients (31%) had significant pain relief (≥50%). Seven out of 13 (54%) reported a ≥50% increase regarding enjoyment of life.ConclusionMultiple QoL- and psychosocial-related themes are related to SCS-outcomes. In order to improve SCS-outcomes for both short- and long-term, these themes should be implemented as a multidimensional approach, both prior to implantation as during follow-up.     

Direct Sciatic Nerve Electrical Stimulation for Complex Regional Pain Syndrome Type 1

ObjectiveFoot and leg pain in complex regional pain syndrome (CRPS) presents a challenge even with neuromodulation techniques such as spinal cord stimulation (SCS). We report our experience with a novo technique of direct sciatic nerve electrical stimulation (DISNES) for intractable foot and leg pain in CRPS I.Materials and MethodsFollowing Research Ethics Board (REB) approval, data were gathered for 16 patients (10 women and 6 men, age 26–61 years) who had been subjected to ipsilateral DISNES. All 16 patients had failed conventional medical management. As well, seven subjects were previously treated with SCS for CRPS I pain. These subjects reported pain relief in the thigh and leg, however the SCS was unable to alleviate the disabling foot pain despite varied and multiple programming techniques. The remaining nine subjects were treated primarily with DISNES. Evaluation was done using visual analog scale (VAS), Oswestry Disability Index version 2 (ODI), and quality of life (EQ-5D and SF-36) scores done both pre-DISNES and at two follow-ups.ResultsVAS scores decreased by 59% at follow-up (F/U) 1 (P = 0.00001) and 46% F/U 2. ODI improving by 40% F/U 1 (P = 0.0038) and 37% F/U 2. SF-36 scores improved by 69% F/U 1 (P = 0.015) and 80% F/U 2. EQ-5D scores improved significantly by F/U 1 (P = 0.00030) but insignificantly at F/U 2 (P = 0.81). There was also a rapid resolution of autonomic features such as edema, hyperemia, and allodynia (within 7–10 days). Three subjects returned to work post-DISNES.ConclusionOur study shows that DISNES helps to control the disabling foot pain in CRPS I, thus improving the quality of life, improving ambulation and decreasing disability. DISNES also alleviates autonomic features and dystonia in CRPS I. Further studies are needed to determine long-term efficacy as this study pool is limited in size and follow-up period.     

Higher Preimplantation Opioid Doses Associated With Long‐Term Spinal Cord Stimulation Failure in 211 Patients With Failed Back Surgery Syndrome

ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.     

Lumbar Spinal Cord Stimulation Can Improve Muscle Strength and Gait Independently of the Analgesic Effect: A Case Report

Spinal cord stimulation (SCS) is widely used for pain relief in patients with failed back surgery syndrome (FBSS), and muscle weakness is a common finding in patients with chronic pain. We present here a single case report of a 47‐year‐old woman, who, after SCS for FBSS, had continuous improvement in lower leg muscle strength and gait, but only transient and minimal pain relief. To the authors’ knowledge, this is only the second published case report of significant improvement in “motor” function, independent of the analgesic effect following SCS in FBSS. If SCS, in fact, does improve muscle strength, new strategies for the management of patients with chronic pain might be opened up. Further studies are needed to verify this hypothesis.     

Spinal Cord Stimulation in Complex Regional Pain Syndrome Type I of Less Than 12‐Month Duration

Introduction: Complex regional pain syndrome type 1 (CRPS‐1) has a 31% probability of becoming chronic. The early use of spinal cord stimulation (SCS) has been recommended as a strategy to prevent chronicity and functional impairment. Methods: In a prospective study, we treated 74 CRPS‐1 patients with a mean disease duration of 17 weeks with standard therapy consisting of physical therapy, topical dimethyl sulfoxide, analgesics, transcutaneous stimulation, and sympathetic blockade. Patients who did not respond to standard therapy were offered a treatment with SCS. In these patients, we investigated the impact on pain, quality of life, and function. Results: Out of these 74 patients treated with standard therapy, six patients were included for early SCS treatment. The overall mean pain relief after one year was 35%. The mental component of the Short Form 36 improved; however, there was no effect on the physical component. None of the SCS treated patients showed a clear improvement in functional outcome. Discussion: We conclude that the feasibility of performing a randomized controlled trial on early SCS therapy in CRPS‐1 is low because of the good disease improvement with standard therapy in the first year after onset. This study raises questions about the need to use SCS early in the course of CRPS‐1 because of the probable lack of additional benefit compared with SCS in chronic CRPS‐1.     

Dual Spinal Cord Stimulation for Complex Pain: Preliminary Study

Objectives To retrospectively analyze by indices of success, patients with chronic complex pain, including, axial low back pain, receiving dual spinal cord stimulation (SCS) systems. Methods Eighteen patients with dual spinal cord stimulators have been retrospectively and nonrandomly analyzed. The preponderance of patients in our study group had failed back surgery syndrome (FBSS). Parameters of success of our therapy included reduction of medication, if any, complications, if any, and satisfaction with therapy and improvement in the quality of life, measured by a visual analogical scale (VAS) from 0 to 10. Patients were asked to rate their overall experience with their SCS systems and were divided into four separate groupings according to their overall rating of their therapy. These four groupings included therapy ratings of excellent (70–100%), good (> 50%), fair (< 50%), and poor (< 30%). Satisfaction with therapy and improvement in quality of life were evaluated on a five‐point scale. Patients were asked to rate changes in their quality of life after therapy using the following normative scale: much better, better, no change, worse, and much worse. All the patients in our study were asked if they would repeat their therapy with dual spinal cord stimulation. Results Paresthesia coverage, overlapping the reported painful region, was obtained in 80% of the patients in our study. The VAS decreased an average of 5.6 (range 2–10) after 6 months and 4.9 (range 2–8) at the end of the study. Six patients (37.5%) reported excellent results; four patients (25%) reported good; three (18.7%), fair and poor. Seventy percent of the patients were satisfied with the treatment and reported an increase in their quality of life. Medications were reduced in 75% of the patients. Thirteen (81%) patients with dual lead SCS therapy were willing to repeat the SCS implant procedure. Complications occurred in 43.7%. Conclusions Dual spinal cord stimulation is appropriate and efficacious for treating complex pathology and complex pain that including pain of the low, axial back.     

Treatment of Failed Back Surgery Syndrome

Objectives. To evaluate the long‐term results of different therapies for failed back surgery syndrome (FBSS). Materials and Methods. From 1992 to 1997, 49 patients were treated for FBSS. Twenty patients were treated medically. Twenty‐four patients, who did not respond to medical therapy, underwent spinal cord stimulator (SCS) implant and five underwent further spine surgery. All patients were evaluated by VAS, PDI, and the Oswestry Scales before treatment and at follow‐up. Leg pain, back pain, work status or daily activities, drug side effects, and use of analgesic medications after implantation were examined. Follow‐up ranged from 24 to 84 months (mean 42 months). Results. At last follow‐up, the patients treated medically demonstrated good results on leg and low back pain in eight cases; in other cases, good results were transitory and several therapeutic courses were necessary to control the pain. Two patients treated medically had substantial side effects. All but two patients treated with SCS demonstrated good results for their leg pain; whereas those treated for back pain with SCS had poor results. Two patients still needed continuous drug administration. Conclusions. Medical therapy is effective for leg and back pain; nevertheless, several courses of therapy may be necessary. SCS is an effective treatment for leg pain, however, its effectiveness on back pain appears to be inadequate.     

An Analysis of the Components of Pain,Function, and Health‐Related Quality of Life in Patients with Failed Back Surgery Syndrome Treated with Spinal Cord Stimulation or Conventional Medical Management

Objectives: Failed back surgery syndrome (FBSS) patients experience pain, functional disability, and reduced health‐related quality of life (HRQoL) despite anatomically successful surgery. Examining sub‐dimensions of health outcomes measures provides insight into patient well‐being. Materials and Methods: The international multicenter PROCESS trial collected detailed HRQoL (EuroQol‐5D; Short‐Form 36) and function (Oswestry Disability Index) information on 100 FBSS patients. Results: At baseline, patients reported moderate‐to‐severe leg and back pain adversely affecting all dimensions of function and HRQoL. Compared with conventional medical management alone, patients also receiving spinal cord stimulation (SCS) reported superior pain relief, function, and HRQoL at six months on overall and most sub‐component scores. The majority of these improvements with SCS were sustained at 24 months. Nonetheless, 36–40% of patients experienced ongoing marked disability (standing, lifting) and HRQoL problems (pain/discomfort). Conclusions: Longer‐term patient management and research must focus on these refractory FBSS patients with persisting poor function and HRQoL outcomes.     

EFNS guidelines on neurostimulation therapy for neuropathic pain

Pharmacological relief of neuropathic pain is often insufficient. Electrical neurostimulation is efficacious in chronic neuropathic pain and other neurological diseases. European Federation of Neurological Societies (EFNS) launched a Task Force to evaluate the evidence for these techniques and to produce relevant recommendations. We searched the literature from 1968 to 2006, looking for neurostimulation in neuropathic pain conditions, and classified the trials according to the EFNS scheme of evidence for therapeutic interventions. Spinal cord stimulation (SCS) is efficacious in failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) type I (level B recommendation). High-frequency transcutaneous electrical nerve stimulation (TENS) may be better than placebo (level C) although worse than electro-acupuncture (level B). One kind of repetitive transcranial magnetic stimulation (rTMS) has transient efficacy in central and peripheral neuropathic pains (level B). Motor cortex stimulation (MCS) is efficacious in central post-stroke and facial pain (level C). Deep brain stimulation (DBS) should only be performed in experienced centres. Evidence for implanted peripheral stimulations is inadequate. TENS and r-TMS are non-invasive and suitable as preliminary or add-on therapies. Further controlled trials are warranted for SCS in conditions other than failed back surgery syndrome and CRPS and for MCS and DBS in general. These chronically implanted techniques provide satisfactory pain relief in many patients, including those resistant to medication or other means.     

Multiple Program Spinal Cord Stimulation in the Treatment of Chronic Pain: Follow-Up of Multiple Program SCS

Objective. Follow-up of 80 patients using multiple program spinal cord stimulation (SCS). Methods. For 30 months, we followed 80 chronic pain patients who had undergone SCS implantations at our center. Thirty-six patients had Failed Back Surgery Syndrome (FBSS). Patients were evaluated in patient-controlled stimulation mode (patients can select one of several specific programs in response to their activities and pain level). We collected visual analog pain scores, patient satisfaction scores, pain maps, and paresthesia maps. Results. We previously reported our preliminary findings (Neuromodulation 1998;1 :30–45). At 24 months all patients were using more than one program. At 30 months, 62 patients (76%) were using more than two programs as their preferred stimulation mode and three patients (4%) were satisfied with only one stimulation program. At 30 months all patients chose patient-controlled stimulation as their preferred mode of stimulation. A total of 18 patients (23%) were explanted. Mean pain scores declined from 8.2 at baseline to 4.8 (p < 0.05, n= 79). Paresthesia overlap was 91% (n= 79). Of the patients with FBSS, 81% reported that they were using their SCS daily. Conclusions. In spinal cord stimulation the use of multiple electrodes and multiple stimulation programs, together with advanced programmability, increases paresthesia overlap, reduces pain scores, and may improve patient satisfaction with SCS therapy. This study indicates a significant patient preference for multiple program SCS, if patients are given the option to choose between a single program SCS system or a multiple program SCS system.     

Intraspinal Analgesia for Nonmalignant Pain: A Retrospective Analysis for Efficacy,Safety and Feasability in 50 Patients

Objectives. To test the efficacy and safety of intraspinal opioids for patients with nonmalignant pain. Design. A retrospective analysis on 50 patients, 37 females and 13 males, who prior to intraspinal analgesia failed all conventional therapies including strong oral opioid trials. Patients were divided into three groups according to pain type: neuropathic, nociceptive, mixed neuropathic/nociceptive. Morphine equivalent doses were noted at intervals of 1, 2, 3, 4, 5, 6, 9, 12, 24, 36, 48, 60, and 72 months. Global evaluation of pain relief (poor, fair, good, excellent) was obtained at each return visit. Dose requirements, escalations, and decreases were noted and analyzed. Side effects and complications of drug infusion or mechanical devises were noted and tabulated. Results. 7 of 7 patients with nociceptive pain had good (29%) to excellent (71%) pain relief. Sixty percent of the 16 patients with neuropathic pain had good (47%) to excellent (13%) pain relief. Seventy-two percent of the total of patients with mixed pain had good (40%) to excellent (32%) pain relief. When further subdivided, only 59% of the failed back/arachnoiditis sufferers had good (41%) to excellent (18%) pain relief while 100% of the mixed group with non-FBSS diagnoses had good (37%) to excellent (63%) pain relief. Conclusions. Long-term intrathecal opioids are efficacious, practical, and safe for the treatment of nonmalignant pain syndromes. FBSS patients respond similarly to intraspinal analgesia as the patients with neuropathic pain, while the group with mixed pain from other non-FBSS causes respond similarly to the nociceptive pain patients.     

Subcutaneous Stimulation as Add-on Therapy to Spinal Cord Stimulation in Patients With Persistent Spinal Pain Syndrome Significantly Increases the Total Electrical Charge per Second: Aspects on Stimulation Parameters and Energy Requirements of the Implanted Neurostimulators

ObjectiveIn our previous multicenter randomized controlled trial, we demonstrated the clinical effectiveness of peripheral nerve field stimulation (PNFS) as add-on therapy to spinal cord stimulation (SCS) for the treatment of chronic back pain in patients with persistent spinal pain syndrome (PSPS) or failed back surgery syndrome (FBSS). To our knowledge, no previous study has investigated the effect of PNFS as an add-on to SCS on the energy consumption of the implanted neurostimulators. Therefore, in this study, we compared the specific stimulation parameters and energy requirements of a previously unreported group of patients with only SCS with those of a group of patients with SCS and add-on PNFS. We also investigated differences that might explain the need for PNFS in the treatment of chronic low back pain.Materials and MethodsWe analyzed 75 patients with complete sets of stimulation parameters, with 21 patients in the SCS-only group and 54 patients in the SCS + PNFS group. Outcome measures were average visual analog scale score, SCS parameters (voltage, frequency, and pulse width), SCS charge per second, and total charge per second. We analyzed baseline characteristics and differences between and within groups over time.ResultsBoth groups had comparable patient characteristics at baseline and showed a significant decrease in back and leg pain. SCS charge per second did not significantly differ between the groups at baseline or at 12 months. The total charge per second was significantly higher in the active SCS + PNFS group than in the SCS-only group at baseline; in the SCS + PNFS group, this persisted for up to 12 months, and the SCS charge per second and total charge per second increased significantly over time.ConclusionsOur results show that add-on PNFS increases the total charge per second compared with SCS alone, as expected. However, further research is needed because our results do not directly explain why some patients require add-on PNFS to treat low back pain.