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Objective We evaluated the cost-effectiveness of wireless spinal cord stimulation (Wireless SCS) with single stage "direct to permanent" implantation vs. screening with temporary electrodes and an external pulse generator followed by implantation of a system for long-term use (IPG SCS). Materials and methods We created a cost model that takes a 2019 United States (U.S.) payer perspective and is based on IPG SCS cost models for subjects with chronic back and/or leg pain. Our six-month decision tree includes the screening trial period (success ≥50% relief) and leads to various levels of pain relief with or without complications for IPG SCS and Wireless SCS and without complications for conventional medical management (CMM). Every three months in the follow-on 15-year Markov model (with costs and quality-adjusted life years discounted 3.5% annually), subjects remain stable or transition to deteriorated health or death. Subjects who fail SCS receive CMM. After 60 Markov cycles, a 100,000-sample simulation reveals the impact of maximum willingness-to-pay (WTP) from $10,000 to $100,000 per quality-adjusted life year on net monetary benefit (NMB). Sensitivity analyses considered the impact of the Wireless SCS screening success rate, Wireless SCS device cost, and IPG SCS device longevity. Results Compared with IPG SCS, Wireless SCS offers higher clinical effectiveness at a lower cost and a higher NMB for our WTP thresholds and is, thus, dominant. Wireless SCS is also cost-effective compared with CMM. Results remain robust with 1) Wireless SCS screening success rates as low as 85% (dominant), 2) the cost of the Wireless SCS devices as high as $55,000 (cost-effective), and 3) IPG SCS devices lasting 12 years (dominant). Conclusions In this model, compared with IPG SCS or with CMM, Wireless SCS is a superior strategy.

This systematic review assessed design characteristics and reporting quality of published randomized clinical trials of spinal cord stimulation (SCS) for treatment of pain in adults and adolescents. The study protocol was registered with PROSPERO (CRD42018090412). Relevant articles were identified by searching the following databases through December 31, 2018: MEDLINE, Embase, WikiStim, The Cochrane Database of Systematic Reviews, and The Cochrane Central Register of Controlled Trials. Forty-six studies were included. Eighty-seven percent of articles identified a pain-related primary outcome. Secondary outcomes included physical functioning, health-related quality of life, and reductions in opioid use. Nineteen of the 46 studies prespecified adverse events as an outcome, with 4 assessing them as a primary outcome. Eleven studies stated that they blinded participants. Of these, only 5 were assessed as being adequately blinded. The number of participants enrolled was generally low (median 38) and study durations were short (median 12 weeks), particularly in studies of angina. Fifteen studies employed an intention-to-treat analysis, of which only seven specified a method to accommodate missing data. Review of these studies identified deficiencies in both reporting and methodology. The review's findings suggest areas for improving the design of future studies and increasing transparency of reporting. Perspective This article presents a systematic review of research methods and reporting quality of randomized clinical trials of SCS for the treatment of various pain complaints. The review identifies deficiencies in both methodology and reporting, which may inform the design of future studies and improve reporting standards.

Supplemental Digital Content is Available in the Text., Spinal cord stimulation (SCS) is an interventional nonpharmacologic treatment used for chronic pain and other indications. Methods for evaluating the safety and efficacy of SCS have evolved from uncontrolled and retrospective studies to prospective randomized controlled trials (RCTs). Although randomization overcomes certain types of bias, additional challenges to the validity of RCTs of SCS include blinding, choice of control groups, nonspecific effects of treatment variables (eg, paresthesia, device programming and recharging, psychological support, and rehabilitative techniques), and safety considerations. To address these challenges, 3 professional societies (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials, Institute of Neuromodulation, and International Neuromodulation Society) convened a meeting to develop consensus recommendations on the design, conduct, analysis, and interpretation of RCTs of SCS for chronic pain. This article summarizes the results of this meeting. Highlights of our recommendations include disclosing all funding source and potential conflicts; incorporating mechanistic objectives when possible; avoiding noninferiority designs without internal demonstration of assay sensitivity; achieving and documenting double-blinding whenever possible; documenting investigator and site experience; keeping all information provided to patients balanced with respect to expectation of benefit; disclosing all information provided to patients, including verbal scripts; using placebo/sham controls when possible; capturing a complete set of outcome assessments; accounting for ancillary pharmacologic and nonpharmacologic treatments in a clear manner; providing a complete description of intended and actual programming interactions; making a prospective ascertainment of SCS-specific safety outcomes; training patients and researchers on appropriate expectations, outcome assessments, and other key aspects of study performance; and providing transparent and complete reporting of results according to applicable reporting guidelines.

Introduction In the PROMISE study, a multinational randomized controlled trial (RCT) of the effectiveness of spinal cord stimulation (SCS) with multicolumn surgical leads as a treatment of low back pain, clinicians followed their usual practice. An early, unplanned safety analysis revealed that the infection rate in Belgium (5/23), where trial duration was a median 21.5 days, was significantly higher than the 1/64 rate observed in the other study countries (median 5.8 days, p 10 days was 24.1% vs. 1.4% for subjects trialed ≤10 days (p

Objectives The recent availability of paraesthesia/sensation free spinal cord stimulation (SCS) modalities allow the design of clinical trials of SCS using placebo/sham controls and blinding of patients, clinicians, and researchers. The aims of this study were to: 1) systematically review the current evidence base of randomized controlled trials (RCTs) of SCS placebo/sham trials and 2) to undertake a methodological critique of their methods. Based on this critique, we developed a checklist for the design and reporting of future RCTs of SCS. Materials and methods Electronic data bases were searched from inception until January 2019 for RCTs of SCS using a placebo/sham control. RCTs with only an active comparator arm were excluded. The results are presented as a narrative synthesis. Results Searches identified 12 eligible RCTs. SCS modalities included paraesthesia stimulation, subthreshold, burst, and high-frequency SCS and were mainly conducted in patients with failed back surgery syndrome, complex regional pain syndrome, and refractory angina. The quality and transparency of reporting of the methods of placebo stimulation, blinding of patients, clinicians, and researchers varied markedly across studies. Conclusions To date the methods of placebo/sham control and blinding in RCTs have been poorly reported, leading to concerns about the validity and replicability of the findings. Important aspects that need to be clearly reported in the design of placebo-/sham-controlled RCTs of SCS include the transparent reporting of stimulation programming parameters, patient position during perception threshold measurement, management of the patient handheld programmer, frequency of recharging, and assessment of the fidelity of blinding.

The aims of this review were to systematically identify the current evidence base of placebo (or “sham”) randomised controlled trials (RCTs) of spinal cord stimulation (SCS) for neuropathic pain and to undertake a meta-analysis to investigate the effectiveness of SCS when compared with a pla

Background "Traditional" spinal cord stimulation (SCS) trials with percutaneous electrodes externalized to a pulse generator (PG) are typically limited in duration due to risk of infection. Newer miniaturized wireless SCS technology eliminates the percutaneous extension (as well as PGs implanted for chronic use), thus facilitating a single-stage implantation after which the device can remain indefinitely. Objective To evaluate fully implanted wireless SCS devices during a 30-day screening trial in subjects with chronic low back pain and leg pain and a history of lumbosacral spine surgery. Methods In a randomized controlled trial of single-stage wireless SCS using a wireless percutaneous system, 99 subjects received either 10 kHz high frequency stimulation (HFS) or lower frequency stimulation (LFS) below 1500 Hz (Bolash R, Creamer M, Rauck R, et al. Wireless high frequency spinal cord stimulation (10 kHz) compared to multi-waveform low frequency spinal cord stimulation in the management of chronic pain in failed back surgery syndrome subjects: preliminary results of a multicenter, prospective, randomized controlled study. Pain Med 2019, https://doi.org/10.1093/pm/pnz019). In this report, we assess the 30-day trial success rate (≥50% pain relief from baseline) and complications. Results The overall trial success rate was 88% (87/99): 92% (46/50) for HFS and 84% (41/49) for LFS (NS). The trial success rate in the 64 subjects with predominant low back pain was 92% (59/64) vs. 80% (28/35) in those with leg pain ≥ low back pain (NS). During the screening trial, one infection occurred (1%) and one subject withdrew and was explanted (1%). Electrode migrations were seen on routine follow-up x-rays in 10 cases (10%). Conclusion Using wireless SCS devices that allow for an extended trial period and evaluation of various waveforms, we observed a high rate trial success rate with both HFS and LFS waveforms, with minimal incidence of infection. Long-term follow-up will address the cost-effectiveness and morbidity associated with this technology, which facilitates single-stage treatment.

Supplemental Digital Content is Available in the Text. Adding multicolumn spinal cord stimulation to optimal medical management improved pain relief, health-related quality of life, and function in a traditionally difficult to treat population of failed back surgery syndrome patients with predominant low back pain., Despite optimal medical management (OMM), low back pain (LBP) can be disabling, particularly after spinal surgery. Spinal cord stimulation (SCS) is effective in reducing neuropathic leg pain; however, evidence is limited for LBP. This prospective, open-label, parallel-group trial randomized (1:1) failed back surgery syndrome (FBSS) patients with predominant LBP to SCS plus OMM (SCS group) or OMM alone (OMM group) at 28 sites in Europe and the Americas. If trial stimulation was successful, a multicolumn SCS system was implanted. Outcomes were assessed at baseline (before randomization) and at 1, 3, 6, and 12 months after randomization. Patients could change treatment groups at 6 months. The primary outcome was the proportion of patients with ≥50% reduction in LBP (responder) at 6 months. Secondary outcomes included change in pain intensity, functional disability, and health-related quality of life (HRQoL). The results are posted at ClinicalTrials.gov under registration number NCT01697358. In the intent-to-treat analysis, there were more responders in the SCS group than in the OMM group (13.6%, 15/110 vs 4.6%, 5/108, difference 9% with 95% confidence interval 0.6%-17.5%, P = 0.036) at 6 months. The SCS group improved in all secondary outcomes compared with the OMM group. The OMM group only improved in HRQoL. In the SCS group, 17.6% (18/102) experienced SCS-related adverse events through 6 months, with 11.8% (12/102) requiring surgical reintervention. Adding multicolumn SCS to OMM improved pain relief, HRQoL, and function in a traditionally difficult-to-treat population of failed back surgery syndrome patients with predominant LBP. Improvements were sustained at 12 and 24 months.

INTRODUCTION Primary data reported in scientific publications provide guidance for improving patient care, expanding indications, identifying research gaps, educating patients, justifying reimbursement, and gaining regulatory approval. Finding and analyzing pertinent publications among the huge volume noted in databases such as PUBMED, however, costs time and effort. This situation demands innovative ways to locate citations of (and the possibility of abstracting data from) papers reporting primary findings. METHODS We created WIKISTIM.org, a searchable easily navigated website, to meet this challenge in our field and devised a taxonomy of data categories specific for various stimulation targets for extracting and posting primary data. We included a discussion section unlimited by time or space to overcome limits posed by traditional letters to the editor. RESULTS Registrants can download single or multiple citations from search results or from the list of papers (sortable by author, title, publication, and year) into a single table. The downloadable data category lists are used to submit completed data entry sheets for upload and for evidence-based comparison across studies as well as for study design, manuscript preparation, and peer review. Registration for WIKISTIM access continues to grow as do the curated citation lists, which are updated monthly and are comprehensive for deep brain stimulation, dorsal root ganglion stimulation, gastric electric stimulation, spinal cord stimulation, and sacral nerve stimulation. CONCLUSIONS Most WIKISTIM entries are limited to citation information and links to published abstracts. As the number of completed datasheets and of stimulation target sections increase, the value of WIKISTIM will increase.

ObjectiveFor many medical professionals dealing with patients with persistent pain following spine surgery, the term Failed back surgery syndrome (FBSS) as a diagnostic label is inadequate, misleading, and potentially troublesome. It misrepresents causation. Alternative terms have been suggested, but none has replaced FBSS. The International Association for the Study of Pain (IASP) published a revised classification of chronic pain, as part of the new International Classification of Diseases (ICD-11), which has been accepted by the World Health Organization (WHO). This includes the term Chronic pain after spinal surgery (CPSS), which is suggested as a replacement for FBSS.MethodsThis article provides arguments and rationale for a replacement definition. In order to propose a broadly applicable yet more precise and clinically informative term, an international group of experts was established.Results14 candidate replacement terms were considered and ranked. The application of agreed criteria reduced this to a shortlist of four. A preferred option—Persistent spinal pain syndrome—was selected by a structured workshop and Delphi process. We provide rationale for using Persistent spinal pain syndrome and a schema for its incorporation into ICD-11. We propose the adoption of this term would strengthen the new ICD-11 classification.ConclusionsThis project is important to those in the fields of pain management, spine surgery, and neuromodulation, as well as patients labeled with FBSS. Through a shift in perspective, it could facilitate the application of the new ICD-11 classification and allow clearer discussion among medical professionals, industry, funding organizations, academia, and the legal profession.

Objective In this study, we sought to characterize contemporary trends in cost and utilization of spinal cord stimulation (SCS). Methods The Healthcare Cost and Utilization Project−National Inpatient Sample was queried for inpatient admissions from 2008 to 2014 where SCS was performed. We then determined the rates and costs of SCS performed in this time frame to treat diagnoses that we classified as device-related complications, degenerative spine disease, pain syndromes, and neuropathies/neuritis/nerve lesions. Least-squares regression was performed to determine the yearly trends for each indication adjusted by the total number of yearly hospitalizations for that diagnosis. Results We identified a total of 6876 admissions in whom an SCS was performed. The overall rate of inpatient SCS procedures performed has decreased by 45% from 2008 to 2014 (14.0 to 7.7 procedures per 100,000 admissions). Adjusted analysis for yearly trends also demonstrated a declining trend for all indications; however, this was not found to be statistically significant, except for device-related complications (P = 0.004). The median inflation-adjusted cost of an admission where SCS was performed increased slightly by 7.4% from $26,200 (IQR: $16,700−$33,800) in 2008 to $28,100 (IQR: $19,600−$36,900) in 2014. Billed hospital charges demonstrated a significant increase with median inflation-adjusted admission charge of $66,068 in 2008 to $110,672 in 2014. Conclusions Despite a declining contemporary trend in inpatient SCS, an increase was noted in admission costs and hospital charges. A significant declining trend was noted in revision SCS implantations due to device-related complications.

Introduction Connectors between implanted stimulator electrodes and pulse generators allow revisions, including battery changes or generator upgrades, to proceed without disturbing uninvolved components, such as the electrode. As new devices are introduced, however, connector incompatibility, even with updated hardware from the same manufacturer, can lead to additional procedures, expense, and morbidity. Materials and methods Following the example of the cardiac pacemaker/defibrillator industry, the Institute of Neuromodulation (IoN) met to explore the possibility of creating connector standards for implanted neurostimulation devices. At a subsequent meeting of the Association for the Advancement of Medical Instrumentation, which coordinates the development of such standards, industry representatives asked for data defining the need for a new standard. Accordingly, IoN prepared an online survey to be sent to the North American Neuromodulation Society mailing list regarding experience with the connectivity of spinal cord stimulation (SCS) generators and electrodes. Results The 87 respondents of 9657 surveyed included 77 clinicians, who reported a total of 42,572 SCS implants and revisions. More than a quarter of revisions (2741 of 9935) required the interconnection of devices made by separate manufacturers, in most cases (n = 1528) to take advantage of a new feature (e.g., rechargeability, new waveform) or because an original component could not be replaced (n = 642). Connector adapters provided by manufacturers were used in less than half (n = 1246) of these cases. Nearly all (94%) of the clinicians agreed that standardized connectors should be developed for SCS, and 86% opined that standardized connectors should be developed for other neurostimulation therapies. Conclusion Those who responded to our survey support the development of standard connectors for implanted stimulators, with voluntary compliance by manufacturers, to mitigate the need for adapters and facilitate interchanging components when appropriate. Other advantages to patients and manufacturers might accrue from the adoption of standards, as technology evolves and diversifies.

Neuromodulation has inherent advantages over many other invasive treatments, in that it is inherently nondestructive and reversible, and clinical evidence attests to its favorable risk/benefit ratio. Spinal cord stimulation (SCS), the most widespread application of neuromodulation, became established before the era of evidence-based medicine, which privileges the results of blinded, randomized controlled trials (RCTs) over other forms of clinical evidence. SCS elicits paresthesia when delivered at conventional frequencies, precluding blinded trials and thus “high-quality evidence” by contemporary standards. Contemporary clinical study design methods are presented here as they apply to neuromodulation in general and SCS in particular, so as to demonstrate advantages in practice. New SCS parameters that reduce or eliminate paresthesia offer new opportunities for blinded clinical trials.

With the “gate theory” of pain as its theoretical foundation, the first spinal cord stimulation (SCS) implant was performed 50 years ago. The earliest electrodes required a laminotomy for implantation, but percutaneous methods developed for stimulation trials were quickly adapted for chronic implantation, reducing invasiveness and making the procedure accessible through nonsurgical specialists. Ongoing developments in solid-state technology and power sources, which made implanted electronics feasible in the 1960s, have made multicontact, multichannel systems with multiple waveform capabilities available today. With growing (albeit still incomplete) understanding of its mechanisms, SCS remains the most common application of neuromodulation.

The most cost-effective treatment of chronic pain provides clinical advantages when compared with competing therapies and/or reduces the consumption of healthcare resources sufficiently to recapture its cost in a reasonable amount of time. This chapter considers how spinal cord stimulation (SCS) meets this challenge. After defining pertinent terms, the chapter reviews cost studies published since 1991 on the use of SCS to treat painful conditions and then discusses ways to improve cost effectiveness, including appropriate patient selection, improving techniques, and improving equipment; the position of SCS in the treatment continuum; and the cost implications of the screening trial. The chapter concludes that if optimal patient selection criteria are adopted and reasonable techniques are used by properly trained clinicians, SCS is cost effective for the treatment of failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), refractory angina, and peripheral vascular disease. Recovery of the initial expense of SCS treatment (cost neutrality) occurs immediately in patients who would otherwise receive coronary artery bypass surgery (CABG) surgery for symptom relief; after 1 year for patients with angina who are not candidates for CABG; and after 3 years for patients with FBSS or CRPS.

Although the most common application of spinal cord stimulation (SCS) has been the treatment of persistent pain following low back surgery, pain in the low back proper has proven more difficult to treat than radiating leg pain. Achieving coverage of the low back by stimulation paresthesia, a necessary condition for pain relief by traditional SCS, requires precise contact placement and/or electrical field control, which have been addressed by a series of technological developments. New SCS waveforms which do not elicit paresthesia continue to use anatomic and radiographic targets defined by traditional SCS, adding clinical benefit.

Objective The purpose of the multicenter, randomized, unblinded, crossover Success Using Neuromodulation with BURST (SUNBURST) study was to determine the safety and efficacy of a device delivering both traditional tonic stimulation and burst stimulation to patients with chronic pain of the trunk and/or limbs. Methods Following a successful tonic trial, 100 subjects were randomized to receive one stimulation mode for the first 12 weeks, and then the other stimulation mode for the next 12 weeks. The primary endpoint assessed the noninferiority of the within-subject difference between tonic and burst for the mean daily overall VAS score. An intention-to-treat analysis was conducted using data at the 12- and 24-week visits. Subjects then used the stimulation mode of their choice and were followed for one year. Descriptive statistics were used analyze additional endpoints and to characterize the safety profile of the device. Results The SUNBURST study demonstrated that burst stimulation is noninferior to tonic stimulation (p

Introduction The International Neuromodulation Society (INS) has determined that there is a need for guidance regarding safety and risk reduction for implantable neurostimulation devices. The INS convened an international committee of experts in the field to explore the evidence and clinical experience regarding safety, risks, and steps to risk reduction to improve outcomes. Methods The Neuromodulation Appropriateness Consensus Committee (NACC) reviewed the world literature in English by searching MEDLINE, PubMed, and Google Scholar to evaluate the evidence for ways to reduce risks of neurostimulation therapies. This evidence, obtained from the relevant literature, and clinical experience obtained from the convened consensus panel were used to make final recommendations on improving safety and reducing risks. Results The NACC determined that the ability to reduce risk associated with the use of neurostimulation devices is a valuable goal and possible with best practice. The NACC has recommended several practice modifications that will lead to improved care. The NACC also sets out the minimum training standards necessary to become an implanting physician. Conclusions The NACC has identified the possibility of improving patient care and safety through practice modification. We recommend that all implanting physicians review this guidance and consider adapting their practice accordingly.

A patient with failed back surgery syndrome reported paresthesia in his hands and arms during a spinal cord stimulation (SCS) screening trial with a low thoracic electrode. The patient's severe thoracic stenosis necessitated general anesthesia for simultaneous decompressive laminectomy and SCS implantation for chronic use. Use of general anesthesia gave the authors the opportunity to characterize the patient's unusual distribution of paresthesia. During SCS implantation, they recorded SCS-evoked antidromic potentials at physiologically relevant amplitudes in the legs to guide electrode placement and in the arms as controls. Stimulation of the dorsal columns at T-8 evoked potentials in the legs (common peroneal nerves) and at similar thresholds, consistent with the sensation of paresthesia in the arms, in the right ulnar nerve. The authors' electrophysiological observations support observations by neuroanatomical specialists that primary afferents can descend several (in this case, at least 8) vertebral segments in the spinal cord before synapsing or ascending. This report thus confirms a physiological basis for unusual paresthesia distribution associated with thoracic SCS.

Introduction: While reference is frequently made to the risk of spinal cord or nerve root injury with the surgical implantation of paddle type spinal cord stimulation (SCS) electrodes, data are lacking on the frequency, causes, and prevention of these complications. Methods: To determine the incidence and frequency of neurologic complications, we performed 1) a comprehensive analysis of the literature to determine the incidence of complications that have caused or could lead to neurologic injury; 2) an analysis of the US Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) data base; and 3) an investigation of manufacturers' data on surgically implanted paddle electrodes. We then convened an expert panel of neurosurgeons experienced in the surgical implantation of paddle electrodes to provide recommendations to minimize the risk of neurologic injury. Results: The scientific literature describes the breadth of neurologic complications that can result from SCS electrode implantation but does not provide interpretable data with respect to the incidence and frequency of these complications. The MAUDE data base is not constructed to be sensitive or specific enough to provide these critical data. Primary data show a risk of neurologic injury from implantation of paddle electrodes below 0.6%. Discussion: Preoperative, intraoperative, and postoperative measures to further minimize this risk are described. Conclusions: This investigation, the first comprehensive evaluation of the incidence and frequency of neurologic injury as a result of SCS paddle electrode implantation, suggests that neurologic injury is a rare, but serious, complication of SCS. The incidence of these complications should be decreased by the adoption of approaches that improve procedural safety and by careful patient follow-up and complication management. Physicians should be aware of these approaches and take every precaution to reduce the risk of neurologic injury. Physicians also should report any adverse event leading to injury or death and work together to improve access to these data.

Objective: This paper presents the protocol of the EVIDENCE study, a multicenter multinational randomized controlled trial to assess the effectiveness and cost-effectiveness of spinal cord stimulation (SCS) with rechargeable pulse generator versus re-operation through 36-month follow-up in patients with failed back surgery syndrome. Study Design: Study subjects have neuropathic radicular leg pain exceeding or equaling any low back pain and meet specified entry criteria. One-to-one randomization is stratified by site and by one or more prior lumbosacral operations. The sample size of 132 subjects may be adjusted to between 100 and 200 subjects using a standard adaptive design statistical method with pre-defined rules. Crossover treatment is possible. Co-primary endpoints are proportion of subjects reporting ≥50% leg pain relief without crossover at 6 and at 24 months after SCS screening trial or re-operation. Insufficient pain relief constitutes failure of randomized treatment, as does crossover. Secondary endpoints include cost-effectiveness; relief of leg, back, and overall pain; change in disability and quality of life; and rate of crossover. We are collecting data on subject global impression of change, patient satisfaction with treatment, employment status, pain/paresthesia overlap, SCS programming, and adverse events. Discussion: As the first multicenter randomized controlled trial of SCS versus re-operation and the first to use only rechargeable SCS pulse generators, the EVIDENCE study will provide up-to-date evidence on the treatment of failed back surgery syndrome.

A 52-year-old woman sought help for intractable lumbosacral pain, which began after she lifted a heavy object and fell onto her back more than 2 decades ago. Additional symptoms included burning, numbness, tingling, and pain in her right hip, posterior thigh, leg, and toes, and diminished sensation and sensitivity throughout her right leg and foot. Muscle spasms/ cramps, which often interrupted sleep, were intermittently present in her right buttock and right lower extremity. Right-foot drop impaired her ability to walk, and she used a wheeled walker with a seat because she could not walk more than a few steps without sitting. Other problems included: Severe pressure-type headaches, chronic abdominal and pelvic pain, cervical and thoracic back pain, frequent urinary tract infections, and urinary incontinence. Her pain increased with sitting, standing, and walking, and had been refractory to ibuprofen 800 mg tid, gabapentin 300 mg tid, oxycodone/acetaminophen 5/325 mg q4h PRN, and cyclobenzaprine 10 mg tid. Her medical history was unremarkable and her family history was notable for above-average height; most women in her paternal family are 5’10’’ to 6’ tall, and most men are 6’4’’ and taller. Many died in their 40s, and her brother and sister had been diagnosed with possible multiple sclerosis. Magnetic resonance imaging (MRI) of her pelvis revealed sacral nerve root cysts that were more completely imaged by sacral MRI (Fig 2). An MRI of the cervical spine from 2007 showed only mild C4-5 disc protrusion, but a repeat MRI in 2009 noted multilevel mild degenerative changes and small (#.6 cm) perineurial cysts at C4-5, C5-6, C6-7, C7-T1. In 2007, an MRI of the thoracic spine was interpreted as normal. The patient stated, ‘‘Everything in my life has been destroyed by these symptoms. It took over 2 decades

OBJECTIVES Healthcare policy makers and payers require cost-effectiveness evidence to inform their treatment funding decisions. Thus, in 2008, the United Kingdom's National Institute of Health and Clinical Excellence analyzed the cost effectiveness of spinal cord stimulation (SCS) compared with conventional medical management (CMM) and with reoperation and recommended approval of SCS in selected patients with failed back surgery syndrome (FBSS). We present previously unavailable details of the National Institute of Health and Clinical Excellence analysis and an analysis of the impact on SCS cost effectiveness of rechargeable implanted pulse generators (IPGs). METHODS We used a decision analytic model to examine the cost effectiveness of SCS versus CMM and versus reoperation in patients with FBSS. We also modeled the impact of nonrechargeable versus rechargeable IPGs. RESULTS The incremental cost-effectiveness of SCS compared with CMM was pound5624 per quality-adjusted life year, with 89% probability that SCS is cost effective at a willingness to pay threshold of pound20,000. Compared with reoperation, the incremental cost-effectiveness of SCS was pound6392 per quality-adjusted life year, with 82% probability of cost-effectiveness at the pound20,000 threshold. When the longevity of an IPG is 4 years or less, a rechargeable (and initially more expensive) IPG is more cost-effective than a nonrechargeable IPG. DISCUSSION In selected patients with FBSS, SCS is cost effective both as an adjunct to CMM and as an alternative to reoperation. Despite their initial increased expense, rechargeable IPGs should be considered when IPG longevity is likely to be short.

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

Objectives. The development of multicontact electrodes and programmable, implanted pulse generators has increased the therapeutic success of spinal cord stimulation (SCS) by enhancing the ability to capture and maintain pain/paresthesia overlap. This study sought to determine if interleaved stimulation and/or frequency doubling improves pain/paresthesia overlap in patients with failed back surgery syndrome. Methods. Using a patient-interactive computer system that quantifies SCS performance and presents stimulation settings in randomized, double-blind fashion, we compared the effect on pain/paresthesia overlap of interleaved stimulation (rapidly interleaved pulse trains using two different contact combinations) vs. standard treatment with a single contact combination, controlling for frequency doubling. Stimulation amplitude (charge per phase, as determined by varying pulse voltage or width) was adjusted to a subjectively comfortable intensity (usage amplitude), which was maintained for all trials in each patient. The number of percutaneous spinal electrodes used (one or two) and the phase angle between interleaved pulses were additional study variables. Results. Multivariate analysis of 266 test results from 15 patients revealed a statistically significant (p ≤ 0.05) association between increased computer-calculated pain/paresthesia overlap and 1) high- and low-frequency interleaved stimulation using two combinations of contacts and 2) frequency doubling using one combination. We found no significant effect for electrode configuration (single or dual), pulse width matching, or phase angle. Conclusions. The statistically significant advantages we observed for SCS with interleaved stimulation are explained, at least in part, by the effects of frequency doubling. These findings have important implications for the design and adjustment of pulse generators.

OBJECTIVE We analyzed the cost-effectiveness and cost-utility of treating failed back-surgery syndrome using spinal cord stimulation (SCS) versus reoperation. MATERIALS AND METHODS A disinterested third party collected charge data for the first 42 patients in a randomized controlled crossover trial. We computed the difference in cost with regard to success (cost-effectiveness) and mean quality-adjusted life years (cost-utility). We analyzed the patient-charge data with respect to intention to treat (costs and outcomes as a randomized group), treated as intended (costs as randomized; crossover failure assigned to a randomized group), and final treatment costs and outcomes. RESULTS By mean 3.1-year follow-up, 13 of 21 patients (62%) crossed from reoperation versus 5 of 19 patients (26%) who crossed from SCS (P < 0.025) [corrected]. The mean cost per success was US $117,901 for crossovers to SCS. No crossovers to reoperation achieved success despite a mean per-patient expenditure of US $260,584. The mean per-patient costs were US $31,530 for SCS versus US $38,160 for reoperation (intention to treat), US $48,357 for SCS versus US $105,928 for reoperation (treated as intended), and US $34,371 for SCS versus US $36,341 for reoperation (final treatment). SCS was dominant (more effective and less expensive) in the incremental cost-effectiveness ratios and incremental cost-utility ratios. A bootstrapped simulation for incremental costs and quality-adjusted life years confirmed SCS's dominance, with approximately 72% of the cost results occurring below US policymakers' "maximum willingness to pay" threshold. CONCLUSION SCS was less expensive and more effective than reoperation in selected failed back-surgery syndrome patients, and should be the initial therapy of choice. SCS is most cost-effective when patients forego repeat operation. Should SCS fail, reoperation is unlikely to succeed.

Object Percutaneous spinal cord stimulation (SCS) electrodes are prone to migration even after scar tissue encapsulation. The authors devised a simple technique to eliminate longitudinal migration. Methods In 99 patients who received implanted percutaneous electrodes, less than 0.1 cm3 of silicone elastomer adhesive was injected between the anchoring sleeve and the electrode. As a result, no patient required revision surgery due to longitudinal electrode migration over a mean follow-up period of 20.2 ± 12.3 months (range 1.8–39.7 months). Postimplant SCS-related surgical procedures were required in 15 patients (15%) for the following indications: infection in three patients, expanded area of pain in four patients, lateral migration after the sutures eroded through the supraspinous ligament in one patient, postural changes in stimulation in one patient, receiver-site pain in two patients, technical failure in three patients, and inadequate pain relief in one patient. Conclusions With modification of the standard technique for implantation of percutaneous SCS electrodes, no longitudinal migration of electrodes was noted in this series of 99 patients.

Use of multicontact electrodes and programmable implanted pulse generators has increased the efficacy of spinal cord stimulation for pain. Some investigators find dual column electrodes advantageous for difficult-to-treat axial low back pain, but we have reported significantly improved measures with a single percutaneous midline electrode vs. dual percutaneous electrodes and even better results with an insulated, 1 × 4, midline electrode. In this study, 10 patients provided computerized, quantitative parameter measures for a temporary percutaneous 1 × 4 electrode and for a permanent insulated 2 × 8 electrode. Compared with the 2 × 8, the 1 × 4 resulted in marginally better patient-rated (109%, p = 0.06) and computer-calculated pain/paresthesia overlap (107%, p = 0.17); higher scaled amplitude to cover the low back (106%, NS); and significantly lower voltage (78%, p = 0.0004), increased extraneous coverage (141%, p = 0.0000), and improved symmetry (25%, p = 0.001). Thus, we observed no significant technical advantage for the insulated 2 × 8 in treating axial low back pain.

Object.Refinement of surgical techniques, especially anterior approaches, for the management of spinal metastases has improved patient outcomes, despite the fact that a complete analysis of the prognostic factors that would inform patient selection has not been undertaken. The authors sought to identify such prognostic factors for neurological outcome and life expectancy in patients with spinal metastases.Methods.The authors used Kaplan—Meier techniques, log-rank comparisons, and a multivariate model stratified by tumor type to identify prognostic factors for duration of ability to walk and survival in patients who underwent surgical treatment for spinal metastases during a decade when all current treatment options were available.Preoperatively, 53 (87%) of the 61 patients in the study population suffered neurological symptoms (for example, weakness) and 52 (85%) were ambulatory. Postoperatively, 59 (97%) were ambulatory. Most patients who survived 6 months (81%) remained ambulatory, as did 66% of those alive at 1.6 years. The median postoperative survival was 10 months. The risk factors for loss of ambulation were preoperative loss of ambulatory ability, recurrent or persistent disease after primary radiotherapy of the operative site, a procedure other than corpectomy, and tumor type other than breast cancer. Prognostic factors for reduced survival were surgical intervention extending over two or more spinal segments, recurrent or persistent disease after primary radiotherapy involving the operative site, diagnosis other than breast cancer, and a cervical spinal procedure.Conclusions.The results of this analysis allowed the authors to create a simple prognostic factor scoring system that can be applied to individual patients. The positive experience derived from this study supports an expanded role for the surgical treatment of metastatic spinal disease.

In this systematic review, we identified and evaluated studies of the cost effectiveness of spinal cord stimulation (SCS) for the treatment of chronic pain. Published reports were identified from a systematic search of a number of general medical electronic databases (Medline, CINAHL, and EMBASE), and specialist economic databases (NHS Centre for Reviews and Dissemination Economic Evaluation Database, and Health Economics Evaluation Database). Reference lists of retrieved reports were also searched, and contact was made with experts in the field. Of the 99 abstracts identified, 14 studies were considered to meet the inclusion criteria of the review. We found that across a range of medical indications, the initial healthcare acquisition costs of SCS implantation are consistently offset by a reduction in post-implant healthcare resource demand and costs. Further research is required to formally examine the cost effectiveness of SCS.

✓ The authors present the case of a 49-year-old woman with disabling bilateral upper-extremity cerebellar tremor that resolved unexpectedly after placement of an intrathecal baclofen pump for lower-extremity spasticity. The tremor amplitude decreased nearly linearly with increasing intrathecal baclofen dosage, and disappeared completely at a dose of 250 µg/day. In this report the authors demonstrate the role of the γ-aminobutyric acidergic system in the pathogenesis of cerebellar tremor, and these findings may lead to a new treatment modality for patients disabled by this manifestation of their disease.

Study Design. A literature review was conducted. Objective. To review the indications and efficacy of spinal cord stimulation, particularly in reference to chronic pain of spinal origin. of Background Data. The first spinal cord stimulation was implanted by Shealy in 1967 via a subarachnoid route. Early systems were plagued with a high rate of complications and technical problems. With the evolving technology, especially the advent of multichannel programmable systems and more precise epidural placement, the ability of spinal cord stimulation to treat various pain syndromes improved. This article reviews the literature on spinal cord stimulation from 1967 to the present. Methods. The literature is reviewed, with a particular focus on recent studies investigating the efficacy of spinal cord stimulation for low back pain. Results. Most studies are limited by the same flaws, namely, retrospective study design. At this writing, the few published randomized prospective studies have suggested that spinal cord stimulation may be superior to repeat surgery.Complication rates have declined to approximately 8%, and reoperation is necessary in approximately 4% of patients. When current percutaneous techniques are used, a lead migration rate lower than 3% may be achieved. For certain topographies, laminotomy leads may be superior, particularly with regard to low back pain. Conclusions. The ultimate efficacy of spinal cord stimulation remains to be determined, primarily because of limitations associated with the published literature. However, on the basis of the current evidence, it may represent a valuable treatment option, particularly for patients with chronic pain of predominately neuropathic origin and topographical distribution involving the extremities. The potential treatment of other pain topographies and etiologies by spinal cord stimulation continues to be studied.

A young patient surviving four years after treatment for primary intracerebral small-cell osteosarcoma is reported. This 16-year-old girl presented with headaches, visual disturbance, and papilledema and was found to have a large, heavily calcified mass in the left parietal lobe. A gross total resection of the tumor was performed and pathologic analysis revealed a small-cell osteosarcoma. Thoracic computerized tomography (CT) scans and a complete bone scan showed no other lesions. The patient received adjuvant chemotherapy and radiotherapy. She continues to do well with no evidence of metastases or local recurrence 4 years after her initial presentation. The clinical, radiographic, surgical, pathologic, and immunohistochemical features of this case, along with therapeutic interventions and outcome, are presented.

Objectives Percutaneous spinal cord stimulation electrodes have a propensity to migrate longitudinally, which is a costly complication that often compromises therapeutic effect. After implementing simple changes to our percutaneous electrode anchoring technique, we no longer encounter this migration. The current retrospective study updates previously reported results. Materials and Methods We retrospectively examined data in a consecutive series of patients in whom we had secured a new percutaneous electrode by injecting < 0.1 cm3 of adhesive into the silicone elastomer lead anchor. From 1998 through 2006, we used whichever anchor was supplied with each lead until we observed one case of migration through a short anchor; thereafter, we used a long, tapered anchor exclusively. From 2007 through 2013, we further modified our technique by adding a fascial incision to accommodate the tip of the anchor and by increasing the strength of our suture material. Results In the first series of 291 patients, followed through July 2007 (mean 4.75 years, range 1.1–9.0 years), 4 (1.37%) experienced electrode migration requiring surgical revision. Only one lead had moved with respect to its anchor; the other three anchors remained securely bonded to their leads. No migration (0.00%) occurred in the second series of 142 patients, followed through 2013 (mean follow-up 2.86 years, range 0.10–5.45 years). Conclusion Improvements to our simple, inexpensive technique apparently have eliminated the most common complication of spinal cord stimulation.

BACKGROUND Pneumosinus dilatans affecting the sphenoid and posterior ethmoid sinuses has been reported in association with spheno-orbital meningiomas and is believed by some authors be a sign of an adjacent meningioma. METHODS We report the case of a 57-year-old man who developed progressive neurologic signs and symptoms consistent with a frontal lobe lesion. Neuroimaging studies revealed a large partially cystic mass at the base of the anterior cranial fossa that appeared to be invading the left frontal lobe and that was associated with pneumosinus dilatans of the adjacent left frontal sinus. RESULTS Although the appearance of the mass by neuroimaging was thought to be most consistent with a malignant glioma, the lesion was found at craniotomy to be a benign meningothelial meningioma. CONCLUSIONS Many previous cases of progressive optic neuropathy associated with pneumosinus dilatans affecting the sphenoid and posterior ethmoid sinuses have been found to be caused by adjacent optic nerve sheath meningiomas. This case provides further evidence that pneumosinus dilatans is a sign of intracranial meningioma.

OBJECTIVE : Associations between psychological and physical states are understood to exist, and the development of standardized psychological tests has allowed quantitative evaluation of this relationship. We tested whether associations exist between psychological test instruments and patients selected for therapeutic trials of spinal cord stimulation (SCS) for chronic, intractable pain. METHODS : Fifty-eight patients selected for SCS were tested prospectively with a battery of standardized psychological tests : Minnesota Multiphasic Personality Inventory with Wiggins content scales, Symptom Check List-90, and Derogatis Affects Balance Scale. Associations between treatment outcomes and preoperative test scores and clinical variables were tested by univariate and multivariate statistical analyses, in which the dependent variables were as follows : 1) the outcome of a therapeutic trial of stimulation (whether the patient derived sufficient reported pain relief with a temporary electrode to proceed with a permanent implant), and 2) long-term outcome of treatment with the permanent implant, as determined by disinterested third-party interview. RESULTS : Significant associations (P ≤ 0.01) were observed between the outcome of the therapeutic trial of stimulation and psychological test results ; patients with low anxiety scores on the Derogatis Affects Balance Scale and with high organic symptoms scores on the Wiggins test were significantly more likely to proceed to permanent implants, as determined by multivariate statistical models. There was an elevation in the Minnesota Multiphasic Personality Inventory hypochondriasis scale in these patients by univariate (P = 0.02), but not by multivariate, models. The multivariate model also identified young age, reproduction of leg pain by straight leg raising, and bilateral leg pain as favorable prognostic factors. The only association with favorable long-term outcome of implantation of a permanent device, by univariate analysis, was an elevated joy score on the Derogatis Affects Balance Scale. Multivariate analysis revealed no statistically significant predictors of long-term outcome. CONCLUSION : Because our study population was selected on the basis of recognized prognostic factors and long clinical experience, it may not be possible to generalize our findings to the overall pain clinic referral population. In the subpopulation we have chosen for SCS trials, psychological testing is of modest value and explains little of the observed variance in outcome. We find little evidence for selecting patients for SCS on the basis of psychological testing. Because self-reported outcome measures may themselves reflect the patient's psychological state, these findings should be considered carefully, in overall clinical context. A prospective study with additional objective outcome measures is underway, which will address some of these issues.

Psychological criteria are important in selecting patients for spinal cord stimulation (SCS), as detailed in the Focus article by Nelson et al. It is useful to broaden our focus, however, and con­ sider the range of purposes for which psychological evaluation, including standardized testing, has been used in chronic pain patients: characterizing popula­ tions of patients with chronic pain, and evaluating responses to treatment, before we undertake predicting responses to treatment, so as to enhance our selection of patients.

This article reviews the role of implantable pumps in the treatment of CNS tumors. Systemic administration of chemotherapeutic agents has been associated with various problems, including adverse systemic effects and decreased concentration of the drug at the target site. Continuous infusion of chemotherapeutic agents with implantable pumps have been used in an attempt to overcome these problems. Various different chemotherapeutic agents have been used for this purpose, and catheters have been placed in the intraspinal, intraventricular and intratumoral locations.