10 kHz High-Frequency Spinal Cord Stimulation for Chronic Thoracic Pain: A Multicenter Case Series and a Guide for Optimal Anatomic Lead Placement.

BACKGROUND: Surgical options for thoracic pain are limited and carry significant risk and morbidity. Spinal cord stimulation has the potential to be used for treatment of thoracic pain, as it has been useful for treating multiple types of chronic pain. Conventional tonic stimulation is limited in the treatment of thoracic pain, as it can produce paresthesia that is difficult to localize. Conversely, high-frequency spinal cord stimulation (HF-SCS) does not activate dorsal column A Beta fibers and does not produce paresthesia, and thus may be more beneficial in treating thoracic back pain not manageable with tonic stimulation. OBJECTIVES: To evaluate (1) the efficacy of 10 kHz HF-SCS for patients with chronic thoracic pain; and (2) appropriate paresthesia-free lead placement and programming targets for 10 kHz HF-SCS for patients with chronic thoracic pain. STUDY DESIGN: Retrospective case series. SETTING: Multisite academic medical center or pain clinic. METHODS: A retrospective chart review was performed on 19 patients with thoracic back pain who underwent HF-SCS implantation. These patients had lead placement and stimulation between the T1-T6 vertebral levels. Outcome measures collected include location of device implant, stimulation settings, and pain scores at baseline, end of trial, and 1, 6, and 12 months postimplant. Follow-up phone calls collected information on if the patient reported functional improvement, improved sleep, or decreased pain medication usage. A Wilcoxon signed-rank test compared differences in mean pain scores across time points. RESULTS: Significantly decreased Visual Analog Scale scores were observed with 17/19 (89.5%) patients demonstrating response to therapy (> 50% reduction in pain scores). These results were sustained relative to baseline at 1, 6, and 12 months postimplant, depending on length of follow-up. Many patients also reported functional improvement (17/19), improved sleep (14/19), and reduction in use of pain medications after implantation (9/19). A total of 15/19 patients reported best relief when contacts over T1 or T2 vertebrae were used for stimulation. LIMITATIONS: This study is limited by its retrospective design. Additionally, including documentation from multiple sites may be prone to selection and abstraction bias. Data were also not available for all patients at all time points. CONCLUSIONS: HF-SCS may be a viable option for significant, long-lasting pain relief for thoracic back pain. There may also be evidence for anatomically based lead placement and programming for thoracic back pain. Randomized, controlled trials with extended follow-up are needed to further evaluate this therapy. KEY WORDS: Thoracic pain, back pain, spinal cord stimulation, high frequency, 10 kHz.

The Importance of the Location of Dorsal Root Ganglion Stimulator Electrodes Within the Nerve Root Exit Foramen.

OBJECTIVE: To quantify the relationship between the electrical power requirement to achieve pain relief and the position of the active electrode of dorsal root ganglion stimulators within the spinal nerve root exit foramen. MATERIALS AND METHODS: Retrospective analysis of prospectively collected data of 92 consecutive patients undergoing dorsal root ganglion stimulation (DRGS) for chronic pain in a single center. Cervical and sacral cases, and failed trials/explanted DRGS were excluded, so we report on 57 patients with 78 implanted leads. Anteroposterior and lateral fluoroscopic images of the lead in the exit foramen were examined, and the active electrode positions were put into categories depending on their location relative to fixed anatomical landmarks. The clinical outcome and the power requirements for each of these groups of electrodes were then analyzed. Overall pain outcome was assessed by numeric pain rating scale score pre-operatively and post-operatively. RESULTS: There was no significant relationship between power requirements and mediolateral electrode position, although the lowest average was observed with electrode positions directly below the center of the pedicle. On lateral x-ray, the lowest power requirements were observed in the electrodes positioned superodorsally or dorsally within the foramen. Importantly, power requirements in this location were consistently low, while the power requirements in other locations were not only higher but also much more variable. Electrodes in the superodorsal position required a median output power almost four times lower than electrodes in other positions (p = 0.002). Clinical outcome was not significantly related to power requirement or foraminal position. CONCLUSION: Aiming for a superodorsal electrode position on lateral intraoperative fluoroscopy is desirable, since siting leads in this location reduces the required stimulator output power very substantially and thus will extend battery life. Position within the foramen does not determine clinical outcome, and so the implanter can safely aim for the low power site without detriment to the analgesic efficacy of the system.

Transcutaneous Spinal Cord Stimulation and Motor Rehabilitation in Spinal Cord Injury: A Systematic Review.

Background. Epidural spinal electrical stimulation at the lumbar spinal level evokes rhythmic muscle activation of lower-limb antagonists, attributed to the central pattern generator. However, the efficacy of noninvasive spinal stimulation for the activation of lower-limb muscles is not yet clear. This review aimed to analyze the feasibility and efficacy of noninvasive transcutaneous spinal cord stimulation (tSCS) on motor function in individuals with spinal cord injury. Methods. A search for tSCS studies was made of the following databases: PubMed; Cochrane Registry; and Physiotherapy Evidence Database (PEDro). In addition, an inverse manual search of the references cited by the identified articles was carried out. The keywords transcutaneous, non-invasive, electrical stimulation, spinal cord stimulation [Mesh term], and spinal cord injury were used. Results. A total of 352 articles were initially screened, of which 13 studies met the inclusion criteria for systematic review. The total participant sample comprised 55 persons with spinal cord injury. All studies with tSCS provided evidence of induced muscle activation in the lower and upper limbs, and applied stimulation at the level of the T11-T12 and C4-C7 interspinous space, respectively. All studies reported an increase in motor response measured by recording surface electromyography, voluntary movement, muscle strength, or function. Conclusions. Although this review highlights tSCS as a feasible therapeutic neuromodulatory strategy to enhance voluntary movement, muscle strength, and function in patients with chronic spinal cord injury, the clinical impact and efficacy of electrode location and current intensity need to be characterized in statistically powered and controlled clinical trials.

Safety and Utility of Spinal Magnetic Resonance Imaging in Patients with High-Frequency Spinal Cord Stimulators: A Prospective Single-Centre Study.

BACKGROUND: Implanted high-frequency spinal cord stimulators at 10 kHz (HF-SCS) have recently acquired conditional approval for magnetic resonance imaging (MRI), including retrospective application to previously implanted devices. Under certain conditions, there are greater specific absorption rate (SAR) scanning restrictions compared to some conventional alternatives. This poses technical challenges to obtain diagnostic quality imaging. OBJECTIVES: To describe our experience with 9 such scans, demonstrating that safe and diagnostically useful images can be obtained despite these restrictions. METHODS: We report a prospective single-centre series of 9 scans within a tertiary neuroscience centre, all obtained within the required SAR limit of ≤0.4 W/kg, and describe the scanning protocol we have developed. We further illustrate this with 2 representative patient cases. RESULTS: The imaging studies were well tolerated without complication. In all cases, the imaging quality was sufficient for the reporting neuroradiologist to answer the clinical question posed. CONCLUSION: Despite technical challenges, MRI is feasible, safe and diagnostically useful in HF-SCS-implanted patients. We would invite other centres that implant these devices to consider the development of their own scanning protocols to avoid the morbidity and inconvenience of explantation or computed tomography myelography. To our knowledge, this is the first reported study of MRI in HF-SCS-implanted patients achieving the requisite SAR limit of ≤0.4 W/kg.

Multicenter, Randomized, Double-Blind Study Protocol Using Human Spinal Cord Recording Comparing Safety, Efficacy, and Neurophysiological Responses Between Patients Being Treated With Evoked Compound Action Potential-Controlled Closed-Loop Spinal Cord Stimulation or Open-Loop Spinal Cord Stimulation (the Evoke Study).

BACKGROUND: The spinal cord (SC) response to stimulation has yet to be studied in a pivotal clinical study. We report the study design of an ongoing multicenter, randomized, double-blind, controlled, parallel-arm study of an evoked compound action potential (ECAP) controlled closed-loop spinal cord stimulation (SCS) system, which aims to gain U.S. Food and Drug Administration approval. METHODS: This study will enroll 134 SCS candidates with chronic trunk and limb pain from up to 20 United States sites. Subjects are randomized 1:1 to receive ECAP-controlled closed-loop or open-loop, conventional SCS. The primary objective is noninferiority of closed-loop stimulation determined by the proportion of subjects with ≥50% reduction in overall trunk and limb pain and no increase in pain medications at the three-month visit. If noninferiority is met, superiority is tested. In addition, measures recommended by IMMPACT (e.g., pain intensity, functional disability, emotional functioning, quality of life, impression of change, and sleep), neurophysiological properties (e.g., SC activation, conduction velocity, chronaxie, and rheobase), and safety are analyzed. DISCUSSION: All approved SCS therapies, regardless of the presence or absence of stimulation induced paresthesias, produce fixed-output stimuli; that is, the energy delivered from the electrode array has a defined output irrespective of the neural response of SC fibers. An SCS system has been developed that directly measures the neurophysiologic activation of the SC to stimulation (i.e., ECAP amplitude) and uses this information in a feedback mechanism to produce closed-loop SCS to maintain optimal and stable activation of the SC. This study represents the first randomized, double-blind, pivotal study in the field of neuromodulation to measure SC activation in ECAP-controlled closed-loop versus open-loop stimulation and is expected to yield important information regarding differences in safety, efficacy, and neurophysiological properties. The potential clinical utility of these objective measurements of SC activation and other neurophysiological properties promises to improve outcomes of SCS for chronic pain patients.

An Exploration of the Experiences and Educational Needs of Patients With Failed Back Surgery Syndrome Receiving Spinal Cord Stimulation.

OBJECTIVE: To explore the experience of spinal cord stimulation (SCS) for patients with failed back surgery syndrome (FBSS). METHODS: Adults with FBSS referred for SCS underwent semistructured interviews at three time points: before their SCS trial, after the trial, and three months after receiving the SCS implant. The face-to-face interviews were audio recorded, transcribed verbatim and analyzed thematically. RESULTS: Twelve adults (8 male, 4 female, aged 38-80 years, pain duration 1-26 years) were recruited. Six themes were identified; 1) What should I expect? 2) Varied outcomes, 3) Understanding pain and this new treatment, 4) Experiences of the SCS journey, 5) Getting used to the device, and 6) Finding out what I need to know. Participants' expectations were varied and the procedures were broadly viewed as minor surgery. Participants' expectations about SCS were not limited to pain relief and included reductions in medication, better sleep, and increased physical activity. Participants' understanding of pain and how SCS purports to work was limited. Throughout the process, practical challenges were identified such as the surgical wound management and battery recharging. Participants received information from multiple sources and identified a range of key information needs including a quick-start guide on how to operate the device and a list of dos and don'ts. CONCLUSIONS: Overall, participants' understanding of SCS was limited. The value participants placed on understanding of the process varied markedly. A list of practical informational needs has been identified. Bespoke, user-friendly, informational tools should be developed from this list to enhance the patient experience of SCS.

Neurostimulation Devices for the Treatment of Neurologic Disorders.

Rapid advancements in neurostimulation technologies are providing relief to an unprecedented number of patients affected by debilitating neurologic and psychiatric disorders. Neurostimulation therapies include invasive and noninvasive approaches that involve the application of electrical stimulation to drive neural function within a circuit. This review focuses on established invasive electrical stimulation systems used clinically to induce therapeutic neuromodulation of dysfunctional neural circuitry. These implantable neurostimulation systems target specific deep subcortical, cortical, spinal, cranial, and peripheral nerve structures to modulate neuronal activity, providing therapeutic effects for a myriad of neuropsychiatric disorders. Recent advances in neurotechnologies and neuroimaging, along with an increased understanding of neurocircuitry, are factors contributing to the rapid rise in the use of neurostimulation therapies to treat an increasingly wide range of neurologic and psychiatric disorders. Electrical stimulation technologies are evolving after remaining fairly stagnant for the past 30 years, moving toward potential closed-loop therapeutic control systems with the ability to deliver stimulation with higher spatial resolution to provide continuous customized neuromodulation for optimal clinical outcomes. Even so, there is still much to be learned about disease pathogenesis of these neurodegenerative and psychiatric disorders and the latent mechanisms of neurostimulation that provide therapeutic relief. This review provides an overview of the increasingly common stimulation systems, their clinical indications, and enabling technologies.

Best Practices in Spinal Cord Stimulation.

STUDY DESIGN: A review of clinical best practices for spinal cord stimulation (SCS). OBJECTIVE: The aim of this study is to summarize published and evidence based guidelines with regards to utilizing SCS, including patient selection, disease indication, perioperative management, complication mitigation strategies, and device selection. Additional focus has been provided on quality care to individual patients by acknowledging the importance of durable outcomes and care delivery costs. SUMMARY OF BACKGROUND DATA: For more than 30 years, SCS has successfully alleviated patient suffering and enhanced the lives of patients with refractory pain conditions. Prospective studies of SCS have consistently demonstrated benefits through reduction of pain, improvement in function, and reduced healthcare expenditures in select patient diagnosis groups. Although the benefits of SCS are well-supported, the clinical application of this therapy varies widely based on physician training and experience, regional clinical practice variations, and insurance coverage. METHODS: This article provides a summary of published studies, case reports, evidence-based guidelines and expert consensus, with the intent of increasing physician competency and enhancing patient care through improved clinical outcomes. RESULTS: A guide to SCS implantation, appropriate patient selection, ranked recommendations for diseases that may most benefit for SCS treatment, complication mitigation strategies, and finally, indications for choosing the most efficacious modality of SCS therapy for specific patients and pain conditions. CONCLUSION: Although SCS has been shown to be safe and effective for a number of pain conditions, emerging SCS modalities promise even greater efficacy over traditional SCS. To achieve this promise, physicians must carefully select and manage their patients and the SCS device. LEVEL OF EVIDENCE: N\A.

Specialty-Based Variations in Spinal Cord Stimulation Success Rates for Treatment of Chronic Pain.

OBJECTIVES: Spinal cord stimulation (SCS) has emerged as an appropriate modality of treatment for intractable chronic pain. The present study examines variations in SCS trial-to-permanent conversion rates based on provider types performing the procedure. MATERIALS AND METHODS: We designed a large, retrospective analysis using the Truven MarketScan data base analyzing adult SCS patients with provider information available, with or without IPG implantation from the years 2007-2012. Patients were categorized based on provider type performing the implantation including anesthesiologists, neurosurgeons, orthopedic surgeons, and physical medicine and rehabilitation (PM&R). Univariate and multivariate models identified factors associated with successful conversion. RESULTS: A total of 7667 unique instances of SCS implants were identified across five providers. Overall, 4842 (63.2%) of those receiving trials underwent permanent SCS system implantation. Anesthesiology performed the majority of implants (62.8%), followed by neurosurgery (22.0%), orthopedic surgery (10.2%), and PM&R (5.3%). Compared to anesthesiologists, both neurosurgeons (OR 10.99, 95% CI [9.11, 13.25]; p < 0.001) and orthopedic surgeons (OR 4.64, 95% CI [3.81, 5.65]; p < 0.001) had significantly higher conversion rates, while PM&R (OR 0.71, 95% CI [0.58, 0.87]; p = 0.001) had significantly lower. Percutaneous implants comprised 5473 (71.4%) of all implants. Neurosurgeons and orthopedic surgeons performed a significantly greater number of paddle implants among the different providers (p < 0.0001). Explant rates were similar across all cohorts analyzed (average 11.6%; p = 0.546). CONCLUSIONS: In this nationwide analysis, our results suggest that over a recent five-year period, conversion rates are highest when SCS trials are performed by neurosurgeons and orthopedic surgeons. The study has important implications for establishing uniform guidelines for training, patient selection, and education of physicians across multiple disciplines.

Clinical Paresthesia Atlas Illustrates Likelihood of Coverage Based on Spinal Cord Stimulator Electrode Location.

OBJECTIVE: Concordant paresthesia coverage is an independent predictor of pain relief following spinal cord stimulation (SCS). Using aggregate data, our objective is to produce a map of paresthesia coverage as a function of electrode location in SCS. METHODS: This retrospective analysis used x-rays, SCS programming data, and paresthesia coverage maps from the EMPOWER registry of SCS implants for chronic neuropathic pain. Spinal level of dorsal column stimulation was determined by x-ray adjudication and active cathodes in patient programs. Likelihood of paresthesia coverage was determined as a function of stimulating electrode location. Segments of paresthesia coverage were grouped anatomically. Fisher's exact test was used to identify significant differences in likelihood of paresthesia coverage as a function of spinal stimulation level. RESULTS: In the 178 patients analyzed, the most prevalent areas of paresthesia coverage were buttocks, anterior and posterior thigh (each 98%), and low back (94%). Unwanted paresthesia at the ribs occurred in 8% of patients. There were significant differences in the likelihood of achieving paresthesia, with higher thoracic levels (T5, T6, and T7) more likely to achieve low back coverage but also more likely to introduce paresthesia felt at the ribs. Higher levels in the thoracic spine were associated with greater coverage of the buttocks, back, and thigh, and with lesser coverage of the leg and foot. CONCLUSION: This paresthesia atlas uses real-world, aggregate data to determine likelihood of paresthesia coverage as a function of stimulating electrode location. It represents an application of "big data" techniques, and a step toward achieving personalized SCS therapy tailored to the individual's chronic pain.

Evidence Gaps in the Use of Spinal Cord Stimulation for Treating Chronic Spine Conditions.

STUDY DESIGN: A review of literature. OBJECTIVE: The aim of this study was to define and explore the current evidence gaps in the use of spinal cord stimulation (SCS) for treating chronic spine conditions. SUMMARY OF BACKGROUND DATA: Although over the last 40 years SCS therapy has undergone significant technological advancements, evidence gaps still exist. METHODS: A literature review was conducted to define current evidence gaps for the use of SCS. Areas of focus included 1) treatment of cervical spine conditions, 2) treatment of lumbar spine conditions, 3) technological advancement and device selection, 4) appropriate patient selection, 5) the ability to curb pharmacological treatment, and 6) methods to prolong efficacy over time. New SCS strategies using advanced waveforms are explored. RESULTS: The efficacy, safety, and cost-effectiveness of traditional SCS for chronic pain conditions are well-established. Evidence gaps do exist. Recently, advancement in waveforms and programming parameters have allowed for paresthesia-reduced/free stimulation that in specific clinical areas may improve clinical outcomes. New waveforms such as 10-kHz high-frequency have resulted in an improvement in back coverage. To date, clinical efficacy data are more prevalent for the treatment of painful conditions originating from the lumbar spine in comparison to the cervical spine. CONCLUSION: Evidence gaps still exist that require appropriate study designs with long-term follow-up to better define and improve the use of this therapy for the treatment of chronic spine pain in both the cervical and lumbar regions. LEVEL OF EVIDENCE: N/A.

Trial Design and Endpoint Evaluation in Clinical Studies Addressing Chronic Back Pain.

STUDY DESIGN: A review of the literature evaluating clinical trials of chronic back pain. OBJECTIVE: To assist physicians in assessing the quality of clinical trial data to make the most informed treatment decisions. SUMMARY OF BACKGROUND DATA: Chronic pain is a tremendous public health issue, affecting close to 100 million adults in the United States, and costs the American people billions of dollars. One traditional treatment approach, the long-term use of opiate medications, has recently come under intense scrutiny for problems with complications, diversion, abuse, addiction, and lack of efficacy. In addition, the Centers for Disease Control and Prevention has recognized that overprescribing opiates has enabled an overdose crisis, and written guidelines that are intended to limit their use. It is for this reason that physicians must have a comprehensive understanding of the range of drug-free alternative therapies available and have the tools needed to rigorously evaluate the chronic pain literature so they can make appropriate treatment decisions. METHODS: An evaluation of how clinical trials are designed and ranked, outcome measures, and costs for a variety of therapies is necessary to determine which treatment option is the most efficacious for an individual patient. RESULTS: Clinical trial data demonstrate that spinal cord stimulation (SCS) is a safe and effective treatment option for many types of chronic pain, including back pain. The last 10 years has brought tremendous advances in the field of neuromodulation. Today, several treatment modalities exist for SCS requiring the physician to be able to critically evaluate and interpret the literature and determine which modality has the strongest evidence. When evaluating clinical trial data of patients with chronic back pain, emphasis must be placed on well designed, randomized controlled trials with long-term follow-up producing level I evidence. These data are obtained in a rigorous manner and are likely to have less bias when compared with lower level studies. CONCLUSION: The level I studies performed to date have provided evidence that treatment with SCS results in sustainable pain reduction and improvements in scores measuring quality of life and patient functioning in those patients with chronic intractable back pain. LEVEL OF EVIDENCE: 5.

Evaluation of the Effectiveness of Percutaneous Octapolar Leads in Pain Treatment with Spinal Cord Stimulation of Patients with Failed Back Surgery Syndrome During a 1-Year Follow-Up: A Prospective Multicenter International Study.

OBJECTIVE: To evaluate the effectiveness and safety of percutaneous octapolar (8-contact) leads in spinal cord stimulation (SCS) treatment of failed back surgery syndrome (FBSS) patients who have not reached their therapy goals with other treatment interventions. METHODS: Our prospective, multicenter, open-label, nonrandomized study included 93 patients ≥ 18 years of age suffering from chronic (≥ 6 months), intractable pain predominantly in the legs. Patients implanted with octapolar lead(s) and a neurostimulator after a successful test trial were followed for 12 months. Patients provided self-reported data on change in visual analog scale (VAS) score for leg pain (primary outcome) and low back pain, quality of life (EuroQol 5 dimensions [EQ-5D] index), sleep, medication use, and paresthesia coverage (secondary outcomes). Adverse events and preferred stimulation settings were documented. RESULTS: Eighty-one (87%) patients had a successful SCS trial. Patients reported significantly improved leg pain relief; average VAS score was 72 ± 17 prior to SCS treatment and 32 ± 24 at 12 months (P < 0.001). Significant decrease in back pain (P < 0.001), improvement in quality of life (P < 0.001), and improvement in sleep (P < 0.05) was observed. Sixty-three percent and 40% of patients were responders (≥ 50% pain reduction) on leg and back pain, respectively, after 12 months. A decrease in medication use was seen for antidepressants and anticonvulsants. Eighty-eight percent of the patients managed with 1 or 2 programs for optimal effect and paresthesia coverage. Twenty-five SCS-related adverse events were registered in 22 patients (24%). Surgical revision due to lead displacement or dysfunction was needed in 6 (6%) of the patients. CONCLUSIONS: Use of percutaneous octapolar SCS leads gives significant long-term pain relief and improvement in quality of life and sleep in FBSS patients. The outcomes are better than reported on 4-contact leads and indicate that the progress in SCS technology that has taken place during the past decade correlates with therapy improvements.

Novel 10-kHz High-frequency Therapy (HF10 Therapy) Is Superior to Traditional Low-frequency Spinal Cord Stimulation for the Treatment of Chronic Back and Leg Pain: The SENZA-RCT Randomized Controlled Trial.

BACKGROUND: Current treatments for chronic pain have limited effectiveness and commonly known side effects. Given the prevalence and burden of intractable pain, additional therapeutic approaches are desired. Spinal cord stimulation (SCS) delivered at 10 kHz (as in HF10 therapy) may provide pain relief without the paresthesias typical of traditional low-frequency SCS. The objective of this randomized, parallel-arm, noninferiority study was to compare long-term safety and efficacy of SCS therapies in patients with back and leg pain. METHODS: A total of 198 subjects with both back and leg pain were randomized in a 1:1 ratio to a treatment group across 10 comprehensive pain treatment centers. Of these, 171 passed a temporary trial and were implanted with an SCS system. Responders (the primary outcome) were defined as having 50% or greater back pain reduction with no stimulation-related neurological deficit. RESULTS: At 3 months, 84.5% of implanted HF10 therapy subjects were responders for back pain and 83.1% for leg pain, and 43.8% of traditional SCS subjects were responders for back pain and 55.5% for leg pain (P < 0.001 for both back and leg pain comparisons). The relative ratio for responders was 1.9 (95% CI, 1.4 to 2.5) for back pain and 1.5 (95% CI, 1.2 to 1.9) for leg pain. The superiority of HF10 therapy over traditional SCS for leg and back pain was sustained through 12 months (P < 0.001). HF10 therapy subjects did not experience paresthesias. CONCLUSION: HF10 therapy promises to substantially impact the management of back and leg pain with broad applicability to patients, physicians, and payers.

Epidural spinal cord stimulation for neuropathic pain: a neurosurgical multicentric Italian data collection and analysis.

BACKGROUND: Spinal cord stimulation (SCS) is a technique used worldwide to treat several types of chronic neuropathic pain refractory to any conservative treatment. The aim of this data collection is to enforce evidence of SCS effectiveness on neuropathic chronic pain reported in the literature and to speculate on the usefulness of the trial period in determining the long-term efficacy. Moreover, the very low percentage of undesired side effects and complications reported in our case series suggests that all implants should be performed by similarly well-trained and experienced professionals. METHOD: A multicentric data collection on a common database from 11 Italian neurosurgical departments started 3 years ago. Two different types of electrodes (paddle or percutaneous leads) were used. Of 122 patients, 73 % (N = 89) were submitted to a trial period, while the remaining patients underwent the immediate permanent implant (N = 33). Statistical comparisons of continuous variables between groups were performed. RESULTS: Most of the patients (80 %) had predominant pain to their lower limbs, while only 17 % of patients had prevalent axial pain. Significant reduction in pain, as measured by variation in visual analogue scale (VAS) score, was observed at least 1 year after implantation in 63.8 % of the cases, 59.5 % of patients who underwent a test trial and 71.4 % of patients who underwent permanent implant at once. No statistical differences were found between the lower-limb pain group and the axial pain group. CONCLUSIONS: No relevant differences in long-term outcomes were observed in previously tested patients compared with patients implanted at once. Through this analysis we hope to recruit new centres, to give more scientific value to our results.

Current challenges in spinal cord stimulation.

OBJECTIVES: This study aims to review the current state of spinal cord stimulation for the treatment of chronic pain associated with failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) and to describe intraspinal targets and stimulation parameters, patient selection, therapy cost-effectiveness, and strategies to improve outcomes. MATERIALS AND METHODS: We drew on professional literature spanning four decades, our work with national and international professional societies, and our own extensive clinical experience to summarize contemporary knowledge of the safety, efficacy, cost-efficiency, and challenges associated with spinal cord stimulation in treating chronic pain. RESULTS: The safety, efficacy, and cost-efficiency of spinal cord stimulation in treating chronic pain associated with FBSS and CRPS are well established through randomized controlled trials and long-term observational studies. Challenges include reducing wait-times before implant, which are associated with lower success rates; increasing awareness of this therapy among referring physicians, patients, and payers; decreasing device-related complications by incorporating advanced technology, improved operative and trialing techniques, and appropriate patient selection; and capturing functional and quality-of-life outcomes. Spinal cord stimulation must be part of an overall treatment plan to manage chronic pain, and must engage physicians, patients, their families, pharmacists, nursing staff, and mental health experts in supporting a return to employment, if possible, and to a full domestic and social life. CONCLUSIONS: Innovation in spinal cord stimulation therapy has intensified with numerous new technical capabilities, safety advances, and novel stimulation targets. This progress holds hope for the many sufferers of chronic pain.

International neuromodulation society critical assessment: guideline review of implantable neurostimulation devices.

INTRODUCTION: Spinal cord stimulation (SCS) is well accepted for the treatment of chronic pain since its beginning in 1967. As its use continues to enter into the chronic pain treatment algorithm earlier, conscience patient selection and durability of the therapy are clearly clinically relevant. To improve treatment efficacy, consensus statements and guidelines were developed. OBJECTIVE: The purpose of this work is to review the relevant guideline statements for implantable neurostimulation therapies to treat chronic pain and to identify guideline gaps and future directions for recommendation platforms. MATERIALS AND METHODS: A systematic literature search through EMBASE, Medline, Cochrane data base, as well as peer-reviewed, nonindexed journals and materials presented at national and international meetings was performed to chronologically identify consensus statements or guideline statements for use of neurostimulation therapies to treat chronic neuropathic pain limited to the English language. RESULTS: From 1998 to 2013, 22 guideline statements were identified. Thirteen of the 22 guidelines were society-sponsored guideline statements from ten societies. Two guideline statements were from research foundations, two were government supported, and one statement was published as a position statement. CONCLUSIONS: The current available guideline statements have clear deficiencies in either scope of coverage, evidence synthesis, or lack of transparency of funding. Improved evidence and best practice/guideline assessment may improve patient outcomes and accessibility to these important modalities. Further prospective comparator randomized data are required to not only provide data of clinical and cost-effectiveness in other indications but also to better describe the position of neurostimulation application within the disease management pathway. Therein cases where there appears to be sufficient evidence and consensus, every effort should be made to secure access to these effective therapies. Importantly, each guideline only has a useful clinical half-life, if not updated. This should be acknowledged by both clinicians and third-party payers. Based on these deficiencies, the International Neuromodulation Society recommended the creation of a consensus conference to examine the appropriate use of neurostimulation for pain and ischemic disease.

Burst spinal cord stimulation evaluated in patients with failed back surgery syndrome and painful diabetic neuropathy.

OBJECTIVE: Spinal cord stimulation (SCS) is used for treating intractable neuropathic pain. Generally, it induces paresthesia in the area covered by SCS. Burst SCS was introduced as a new stimulation paradigm with good pain relief without causing paresthesia. Good results have been obtained in patients who were naive to SCS. In this study we assess the effectiveness of burst stimulation in three groups of chronic pain patients who are already familiar with SCS and the accompanying paresthesia. METHODS: Forty-eight patients with at least six months of conventional, tonic stimulation tested burst stimulation for a period of two weeks. They were classified in three different groups: a cross-section of our population with painful diabetic neuropathy (PDN), a cross-section of our population with failed back surgery syndrome (FBSS), and FBSS patients who over time had become poor responders (PR) to SCS. Visual analog scale scores for pain were assessed prior to implantation, with tonic stimulation, and after two weeks of burst stimulation. RESULTS: Burst stimulation reduced pain significantly for almost all patients. When compared with tonic stimulation, burst stimulation led to a significant additional pain reduction of on average 44% in patients with PDN (p < 0.001) and 28% in patients with FBSS (p < 0.01). Patients from the PR group benefitted less from burst stimulation on average. In addition, burst stimulation caused little or no paresthesia whereas tonic stimulation did induce paresthesia. Most patients preferred burst stimulation, but several preferred tonic stimulation because the paresthesia assured them that the SCS was working. CONCLUSION: About 60% of the patients with tonic SCS experienced further pain reduction upon application of burst stimulation.

Impact of the National Institute for Health and Care Excellence (NICE) guidance on medical technology uptake: analysis of the uptake of spinal cord stimulation in England 2008-2012.

BACKGROUND: The National Institute for Health and Care Excellence (NICE) Technology Appraisal Guidance on spinal cord stimulation (SCS) was published in 2008 and updated in 2012 with no change. This guidance recommends SCS as a cost-effective treatment for patients with neuropathic pain. OBJECTIVE: To assess the impact of NICE guidance by comparing SCS uptake in England pre-NICE (2008-2009) and post-NICE (2009-2012) guidance. We also compared the English SCS uptake rate with that of Belgium, the Netherlands, France and Germany. DESIGN: SCS implant data for England was obtained from the Hospital Episode Statistics (HES) database and compared with other European countries where comparable data were available. RESULTS: The HES data showed small increases in SCS implantation and replacement/revision procedures, and a large increase in SCS trials between 2008 and 2012. The increase in the total number of SCS procedures per million of population in England is driven primarily by revision/replacements and increased trial activity. Marked variability in SCS uptake at both health regions and primary care trust level was observed. CONCLUSIONS: Despite the positive NICE recommendation for the routine use of SCS, we found no evidence of a significant impact on SCS uptake in England. Rates of SCS implantation in England are lower than many other European countries.