Spinal Cord Stimulation Trial Research Articles

Bleeding Complications in Patients Undergoing Percutaneous Spinal Cord Stimulator Trials and Implantations.

Spinal cord stimulators (SCS) are indicated for the management of multiple pain states with strong evidence. Recent guidelines recommend discontinuing aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) for the described procedures. The goal of this investigation is to assess the rate of bleeding and neurologic sequelae in patients undergoing SCS trials and implantation. This is a retrospective review from 2005 through 2014 of all patients 18 years or older undergoing the following procedures: Percutaneous SCS implantations, SCS revisions, and SCS trials. Baseline characteristics, antiplatelet and anticoagulation medications, coagulation parameters, and procedural details were extracted. The primary outcome was the presence of a bleeding complication within 31 days of the procedure requiring emergency medicine, neurology, or neurosurgical evaluation. The neurological complication was independently categorized for its potential relationship to procedural bleeding, and periprocedural red blood cell transfusion requirements were analyzed as a secondary outcome. A total of 642 percutaneous SCS procedures were performed on 421 unique patients, including 346 SCS trials, 255 SCS implantations, and 41 revision surgeries. Patients had received aspirin or NSAIDs within 7 days of needle placement for 101 procedures (15.7%). There were no bleeding or neurological complications identified in this cohort. Although the incidence of epidural hematoma is low, the development of bleeding complications following SCS lead placement can be devastating. In the present investigation, we identified no cases of epidural hematoma following percutaneous SCS lead placement, including more than 100 patients receiving aspirin or NSAIDs. Future investigations with larger numbers are needed to better define the relationships between periprocedural aspirin and NSAID utilization and bleeding complications.

Mania reduces perceived pain intensity in patients with chronic pain: preliminary evidence from retrospective archival data.

ObjectiveBipolar disorder is associated with poor pain outcomes, but the extant literature has not taken into account how mania or hypomania – a central feature of bipolar disorders – influences pain intensity. The objective of this study was to describe whether patients recalled experiencing reduced pain intensity during manic or hypomanic episodes.Design and settingThis study used a retrospective design using archival data from patient’s medical records.SubjectsA total of 201 patients with chronic pain with bipolar I (39.6%) or bipolar II (60.4%) disorder who were undergoing a psychological evaluation for an interventional pain procedure were included in this study.MethodsPatients underwent a semistructured interview where they were asked if they recalled reductions in pain intensity during their most recent manic or hypomanic episode. The proportion of patients who responded “yes” versus “no” to this question was the primary outcome variable.ResultsResults reveal that 64.2% of patients recalled experiencing a reduction in pain intensity during their most recent manic or hypomanic episode.ConclusionPerceptions of reduced pain intensity during mania or hypomania may contribute to a cycle of increased activity during manic episodes, which may increase pain over time. It may also lead to false-positive findings on spinal cord stimulator trials and diagnostic pain blocks, among other interventional pain procedures. The preliminary findings of this study highlight the clinical importance of assessing for bipolar disorders in patients with chronic pain.

Subcutaneous Stimulation as ADD-ON Therapy to Spinal Cord Stimulation Is Effective in Treating Low Back Pain in Patients With Failed Back Surgery Syndrome: A Multicenter Randomized Controlled Trial.

Suppression of back pain with traditional spinal cord stimulation (SCS) in failed back surgery syndrome patients is often insufficient. The objective of this study was to investigate the efficacy of subcutaneous stimulation (SubQ) as ADD-ON therapy to SCS in treating back pain in failed back surgery syndrome patients. Patients with a minimal pain score of 50 on a 100 mm visual analog scale for both leg and back pain were eligible. If pain reduction after trial SCS was ≥50% for the leg but <50% for the back, patients received additional SubQ leads and were randomized in a 1:1 ratio in a study arm with subcutaneous leads switched on (SubQ ADD-ON) and an arm with subcutaneous leads switched off (Control). The primary outcome was the percentage of the patients, at three months since implantation, with ≥50% reduction of back pain. A total of 97 patients were treated with SCS for leg and back pain. Of these, 52 patients were randomized and allocated to the Control group (n = 24) or to the SubQ ADD-ON group (n = 28). The percentage of patients with ≥50% reduction of back pain was significantly higher in the SubQ ADD-ON group (42.9%) compared to the Control group (4.2%). Mean visual analog scale for back pain, at three months, was a statistically significant 28.1 mm lower in the SubQ ADD-ON group compared to the Control group. Subcutaneous stimulation as an ADD-ON therapy to SCS is effective in treating back pain in failed back surgery syndrome patients where SCS is only effective for pain in the leg.

Effectiveness of Spinal Cord Stimulation in Chronic Spinal Pain: A Systematic Review

Background: Chronic neuropathic pain has been recognized as contributing to a significant proportion of chronic pain globally. Among these, spinal pain is of significance with failed back surgery syndrome (FBSS), generating considerable expense for the health care systems with increasing prevalence and health impact. Objective: To assess the role and effectiveness of spinal cord stimulation (SCS) in chronic spinal pain. Study Design: A systematic review of randomized controlled trials (RCTs) of SCS in chronic spinal pain. Methods: The available literature on SCS was reviewed. The quality assessment criteria utilized were Cochrane review criteria to assess sources of risk of bias and Interventional Pain Management Techniques – Quality Appraisal of Reliability and Risk of Bias Assessment (IPM – QRB) criteria for randomized trials. The level of evidence was based on a best evidence synthesis with modified grading of qualitative evidence from Level I to Level V. Data sources included relevant literature published from 1966 through March 2015 that were identified through searches of PubMed and EMBASE, manual searches of the bibliographies of known primary and review articles, and all other sources. Outcome Measures: RCTs of efficacy with a minimum 12-month follow-up were considered for inclusion. For trials of adaptive stimulation, high frequency stimulation, and burst stimulation, shorter follow-up periods were considered. Results: Results showed 6 RCTs with 3 efficacy trials and 3 stimulation trials. There were also 2 cost effectiveness studies available. Based on a best evidence synthesis with 3 high quality RCTs, the evidence of efficacy for SCS in lumbar FBSS is Level I to II. The evidence for high frequency stimulation based on one high quality RCT is Level II to III. Based on a lack of high quality studies demonstrating the efficacy of adaptive stimulation or burst stimulation, evidence is limited for these 2 modalities. Limitations: The limitations of this systematic review continue to require future studies illustrating effectiveness and also the superiority of high frequency stimulation and potentially burst stimulation. Conclusion: There is significant (Level I to II) evidence of the efficacy of spinal cord stimulation in lumbar FBSS; whereas, there is moderate (Level II to III) evidence for high frequency stimulation; there is limited evidence for adaptive stimulation and burst stimulation. Key words: Neuropathic pain, chronic spinal pain, failed back surgery syndrome, spinal cord stimulation, high frequency stimulation, burst stimulation, adaptive stimulation

Spinal Cord Stimulation (SCS) for Pain Control in a Quadriplegic Patient: A Case Report

Background: There are reports of pain relief from spinal cord stimulation (SCS) in patients with incomplete spinal cord injuries. However, the results for pain relief from SCS in patients with complete spinal cord injury are dismal. Patients with complete spinal cord injury therefore are generally not considered suitable candidates for SCS. The authors report a case in which a quadriplegic patient with cervical spinal cord injury got significant pain relief from spinal cord stimulation. Methods: The patient is 41 years old with quadriplegia secondary to C5-6 injury. He has no function below the level of the injury except for a few patchy areas of sensation. Ten years after the injury the patient had hemorrhoidectomy. This resulted in severe pain in the anal pain. The treatment for pain failed conservative treatment. He however did have good response to a trial of spinal cord stimulation through an epidural lead placed at T8-T9 vertebral body level. Permanent implantation of spinal cord stimulator was therefore performed. Results: At preoperative evaluation the patient rated his pain as a 7/10. Presently at 2 years’ follow-up the patient rates his pain at 1/10. Conclusions: Spinal cord stimulation proved to be a successful means of achieving adequate pain relief in a patient who had complete loss of motor function below the level of the injury. Therefore, although patients with such condition are unlike to benefit from SCS it is worthwhile trying this treatment if no other option is available there.

Paraplegia following cervical epidural catheterization using loss of resistance technique with air: a case report.

We report a case of paraplegia without neurologic deficit of upper extremities following cervical epidural catheterization using air during the loss of resistance technique. A 41-year-old woman diagnosed with complex regional pain syndrome had upper and lower extremity pain. A thoracic epidural lead was inserted for a trial spinal cord stimulation for treating lower extremity pain and cervical epidural catheterization was performed for treating upper extremity pain. Rapidly progressive paraplegia developed six hours after cervical epidural catheterization. Spine CT revealed air entrapment in multiple thoracic intervertebral foraminal spaces and surrounding epidural space without obvious spinal cord compression before the decompressive operation, which disappeared one day after the decompressive operation. Her paraplegia symptoms were normalized immediately after the operation. The presumed cause of paraplegia was transient interruption of blood supply to the spinal cord through the segmental radiculomedullary arteries feeding the spinal cord at the thoracic level of the intervertebral foramen caused by the air.

Comparison of Conventional and Kilohertz Frequency Epidural Stimulation in Patients Undergoing Trialing for Spinal Cord Stimulation: Clinical Considerations

Compare therapeutic response of patients to conventional versus high-frequency spinal cord stimulation (SCS). Twelve patients with back and leg pain who met standard clinical criteria for a trial of conventional SCS (low-frequency stimulation [LFS]) participated in a half-day session of high-frequency stimulation (HFS) during their weeklong conventional trial. HFS consisted of frequencies ranging from 50 Hz to 4 kHz, or 100 Hz to10 kHz, at constant voltage settings increasing from 0.5 V to 10 V. Visual Analog Scale scores from 0 to10 were recorded, along with notes of any clinical discomfort and open patient comments. Two of 12 patients had no benefit from either LFS or HFS. In the remaining 10 patients, paresthesias were significantly altered by HFS, and four experienced complete elimination of paresthesias. Five patients preferred HFS to LFS, with an additional three preferring both equally. Abrupt sensation to the onset of HFS was described in six patients, and in ten patients, HFS allowed maximum voltage stimulation of 10 V without discomfort. The four patients who did not have a successful trial of stimulation had significantly longer duration of pain compared to the eight patients who went on to permanent implant (11.2 vs. 4.3 years, P = 0.04). HFS significantly altered the feeling of paresthesias in the majority of patients (ten of 12), was preferred to LFS in five of 12 patients, and non-inferior to LFS in eight of 12 patients. Both 4 kHz and 10 kHz stimulation allowed patients to benefit from HFS. HFS allowed maximum voltage stimulation without discomfort.

An International Survey to Understand Infection Control Practices for Spinal Cord Stimulation

Surgical site infections (SSIs) are associated with significant healthcare costs and morbidity. Limited research exists specific to the prevention of spinal cord stimulation (SCS) SSIs. The objectives of this international survey were to examine current infection control practices for SCS trials and implants and to compare reported responses with evidence-based recommendations. A 33-question survey was developed based on an extensive literature review for infection control policies. The survey was hosted on the Internet. Dispersion of the survey occurred through professional associations and device manufacturers. Responses to 15 questions directly related to defined CDC, NICE, and SCIP evidence-based infection control practice recommendations were classified as either compliant or noncompliant. The survey was open for 20 days. Responses also were grouped and analyzed based on geographic location, practice location, and procedural volumes. Five hundred six physicians responded to the survey. Compliance rates for CDC, NICE, SCIP infection control practice recommendations were low with only four of the 15 questions having compliance rates ≥80%. Areas associated with high levels of noncompliance included weight-based antibiotic dosing, hair removal strategies, double gloving, surgical dressing, skin antiseptic agent selection, and postoperative continuation of antibiotics. Geographic and practice type variations existed for particular infection control practices. Procedural volume influenced operative implant times with low physician procedural volumes associated with extended operative times. The survey provided significant insight into current practices and will assist in the development of specific SCS infection control policies. Based on the survey, further education is warranted on infection control strategies for physicians performing spinal cord stimulator trials and implants.

Intensity Modulation: A Novel Approach to Percept Control in Spinal Cord Stimulation.

Spinal cord stimulation (SCS) can be effective for neuropathic pain, but clinical benefit is sometimes inadequate or is offset by stimulation-induced side-effects, and response can be inconsistent among patients. Intensity-modulated stimulation (IMS) is an alternative to tonic stimulation (TS) that involves continuous variation of stimulation intensity in a sinusoidal pattern between two different values, sequentially activating distinct axonal populations to produce an effect that resembles natural physiological signals. The purpose of this study is to evaluate the effect of IMS on the clinical effect of SCS. Seven patients undergoing a percutaneous SCS trial for postlaminectomy syndrome were enrolled. Thresholds for perception, pain relief, and discomfort were measured and used to create patient-specific models of axonal activation and charge delivery for both TS and IMS. All participants underwent three two-min periods of blinded stimulation using TS, IMS, and placebo, and were asked to describe the effect on quality of the sensory percept and pain relief. All participants perceived IMS differently from placebo, and five noted significant differences from TS that resulted in a more comfortable sensation. TS was described as electric and tingling, whereas IMS was described as producing a focal area of deep pressure with a sense of motion away from that focus. The anatomic location of coverage was similar between the two forms of stimulation, although one participant reported better lower back coverage with IMS. Computer modeling revealed that, compared with TS, IMS involved 36.4% less charge delivery and produced 78.7% less suprathreshold axonal activation. IMS for SCS is feasible, produces a more comfortable percept than conventional TS, and appears to provide a similar degree of pain relief with significantly lower energy requirements. Further studies are necessary to determine whether this represents an effective alternative to tonic SCS for treatment of neuropathic pain.

Peripheral and Neuraxial Chemical Neurolysis for the Management of Intractable Lower Extremity Pain in a Patient with Terminal Cancer

We present the case of a 74-year-old man with Stage IV metastatic, multifocal, malignant fibrous histiocytoma (T2b, N1, M1, G4) invading the proximal area of the left lower extremity and resulting in intractable neuropathic pain along the distribution of the femoral nerve. He described the pain as being so severe to cause inability to ambulate without assistance or to sleep in a supine or prone position. After a spinal cord stimulation trial and a trial of intrathecal (IT) hydromorphone, both performed at an outside institution, had failed to achieve adequate pain relief, we decided to perform a femoral nerve chemical neurolysis with phenol under ultrasound (US) guidance. The intervention provided 6 months of almost complete pain relief. With the tumor spreading in girth distally and proximally to the scrotal and pelvic areas as well as to the lungs, and pain returning back to baseline, we proceeded with a second femoral nerve chemical neurolysis. Unfortunately we were not able to achieve adequate pain relief. Therefore we opted to proceed with a diagnostic injection of local anesthetic under fluoroscopic guidance at the left L2, L3, and L4 nerve roots level. This intervention provided 100% pain relief and was followed, a few days later, by chemical neurolysis with phenol 3%. The patient reported complete pain relief with the procedure and no sensory-motor related side effects or complications. He was able to enjoy the last 6 weeks of life with his wife and family, pain-free. With this report we add to the limited literature available regarding the management of intractable cancer pain with chemical neurolysis in and around the epidural space. Key words: Cancer, pain, chemical neurolysis, peripheral, neuraxial

The Use of Spinal Cord Neuromodulation in the Management of HIV-Related Polyneuropathy

Background: The prevalence of HIV-related neuropathy may rise nationwide as Highly Active Antiretroviral Therapy (HAART) usage and HIV-survival rates increase, resulting in higher referral rates to pain practitioners for analgesic strategies. However, if patients’ symptoms are refractory to conservative measures, an advanced interventional approach may be indicated. Objective: We present 2 cases of successful use of spinal cord neuromodulation in the treatment of HIV-related neuropathy. Study Design: Case Report Methods: One patient experienced severe lower extremity burning pain, progressively worsening over the past 6 years. He had trouble ambulating, and pain was refractory to conservative treatments. The other patient suffered from low back pain and distal symmetrical polyneuropathy. A remote lumbar discectomy prior to his development of HIV disease resulted in marked improvement in lumbar spinal pain, but subsequent later development of neuropathic pain remained refractory to different treatment modalities. Results: Both patients reported more than 90% improvement in pain during the spinal cord stimulator (SCS) trial, which led to permanent SCS implantation with equivalent success rates. One of them was followed up for 3 years, and another one for 14 months before he moved overseas. Both of them reported an improved quality of life, reductions in the use of oral opioid analgesics, and increased ability to participate in daily activities without limitations. Neither patient sustained any infectious complications, lead migration, or required battery changes. Limitations: Controlled double blinded studies with a higher number of patients are needed to prove efficacy in these patients. Conclusion: These 2 cases demonstrate that SCS neuromodulation is a safe, viable, and efficacious option for patients whose HIV-related neuropathic type pain is refractory to conventional treatment modalities. Our patients appear to be the first case reports that show a remarkable efficacy of SCS in the management of HIV-related polyneuropathy. Key words: HIV neuropathy, spinal cord stimulation, lower extremity pain, chronic pain, neuropathic pain

Treatment-Limiting Complications of Percutaneous Spinal Cord Stimulator Implants: A Review of Eight Years of Experience From an Academic Center Database.

The study aims to evaluate the long-term implant survival and complications of spinal cord stimulation (SCS) leading to surgical revision or explant in patients treated for chronic noncancer pain. This is a retrospective study of all patients who underwent a percutaneous spinal cord stimulation trial followed by implant in an academic Pain Medicine division by four practitioners from 2007 to 2013, with follow-up data through April 2014. A total of 345 patients were considered candidates for dorsal column stimulation and underwent a trial. Two hundred thirty-four patients were implanted with an implant-to-trial ratio of 67-86% across various chronic pain entities (postlaminectomy syndrome, complex regional pain syndrome, small-fiber peripheral neuropathy, abdominal/pelvic pain, nonsurgical candidates with lumbosacral neuropathy, and neuropathic pain not otherwise specified), with the exception of nonsurgical candidates with lumbosacral neuropathy who had an implant ratio of 43%. The complication rate was 34.6%, with the hardware related being the most common reason, comprising 74.1% of all complications. The revision and explant rates were 23.9% each. The most common reason for explant was loss of therapeutic effect (41.1%). SCS is an effective treatment for chronic noncancer pain. It is a minimally invasive procedure, safe, and with good long-term outcomes. However, the surgical revision and explant rates are relatively high. As the use of SCS continues to grow, research into the causes of and risk factors for SCS-related complications is paramount to decrease complication rates in the future.

The Successful Treatment of Opioid Withdrawal-Induced Refractory Muscle Spasms with 5-HTP in a Patient Intolerant to Clonidine

Instituting drug holidays for chronic opioid using patients is becoming commonplace for pain practitioners initiating procedures such as intrathecal pump or spinal cord stimulator trials. As such, pain practitioners need to be adept in their management of acute opioid withdrawal. Successfully weaning an opioid dependent patient off of chronic opioids requires a thorough knowledge of the available adjuvants to assist in this process. However, that selection can become exhausted by adjuvant side effects or by ineffective attenuation of opioid withdrawal symptoms. In that case, novel drugs, or novel application of currently available medications must be sought after to assist in the drug holiday. We present a case in which refractory muscle spasms secondary to opioid withdrawal were successfully treated with an over-the-counter supplement that is not typically used for the attenuation of opioid withdrawal symptoms. In a patient intolerant to the side effects of clonidine, we were able to successfully wean chronic opiates by treating refractory muscle spasms with the serotonin precursor, 5-hydroxytryptophan (5-HTP). We hypothesize that our success with this medication gives further credence to the role of serotonin in opioid withdrawal somatic symptomatology, and supports the need for future research to clarify the role of serotonin precursors or serotonin modulating drugs as potential alternatives in those unable to follow standard treatment protocols. Key words: 5-hydroxytryptophan (5-HTP), opioid withdrawal, muscle spasms, serotonin, drug holiday, chronic pain

Dynamic Pain Phenotypes are Associated with Spinal Cord Stimulation-Induced Reduction in Pain: A Repeated Measures Observational Pilot Study.

Spinal cord stimulation (SCS) has become a widely used treatment option for a variety of pain conditions. Substantial variability exists in the degree of benefit obtained from SCS and patient selection is a topic of expanding interest and importance. However, few studies have examined the potential benefits of dynamic quantitative sensory testing (QST) to develop objective measures of SCS outcomes or as a predictive tool to help patient selection. Psychological characteristics have been shown to play an important role in shaping individual differences in the pain experience and may aid in predicting responses to SCS. Static laboratory pain-induction measures have also been examined in their capacity for predicting SCS outcomes. The current study evaluated clinical, psychological and laboratory pain measures at baseline, during trial SCS lead placement, as well as 1 month and 3 months following permanent SCS implantation in chronic pain patients who received SCS treatment. Several QST measures were conducted, with specific focus on examination of dynamic models (central sensitization and conditioned pain modulation [CPM]) and their association with pain outcomes 3 months post SCS implantation. Results suggest few changes in QST over time. However, central sensitization and CPM at baseline were significantly associated with clinical pain at 3 months following SCS implantation, controlling for psycho/behavioral factors and pain at baseline. Specifically, enhanced central sensitization and reduced CPM were associated with less self-reported pain 3 months following SCS implantation. These findings suggest a potentially important role for dynamic pain assessment in individuals undergoing SCS, and hint at potential mechanisms through which SCS may impart its benefit.

Spinal Cord Stimulation Failures in Refractory Chronic Pain

Background: Spinal cord stimulation (SCS) is a well-established modality for the treatment of refractory chronic pain and may utilize percutaneous or paddle leads. Methods: The study is conducted at the Unit of Functional Neurosurgery of University “Magna Graecia” of Catanzaro. We perform a retrospective review of our prospective database of 523 SCS patients undergoing surgery for routine indications between January 1993 and December 2013 to evaluate failures rates during trial period and during chronic stimulation. Results: SCS trial was less effective for patients with differentiation neuropathic pain and post herpetic pain. Patients with allodynic dominant pain can feel unpleasant or painful parenthesis during trial stimulation. SCS trial has presented a very low hardware-associated complication rate (lead migration 1.3%) and absence of biological complications. During chronic SCS 29% of cases had equipment failures. In particular mechanical failures occurred in 18% of cases with 8.5% of lead displacements or migrations and 9.5% of lead breakages; biological failures occurred in 11% of cases with 6% of skin erosions and 5% of infections. Conclusion: SCS is a minimally invasive procedure effective in managing medically intractable pain of various origins. Despite advances in the design and production of SCS systems, these devices remain prone to failure from various causes. A careful analysis of mechanical complications coupled to a clinical strategy to minimize the tensile loads on the components of the system should lead to an improvement of the performance of the SCS implanted system and the effectiveness of the stimulation and the long-term reduction in the rate of complications that currently it remains quite significant.

Cervical and cervicomedullary spinal cord stimulation for chronic pain: Efficacy and outcomes

BackgroundThe role for spinal cord stimulation (SCS) in the management of chronic spinal cord forms of pain involving cervical dermatomes or the cervicomedullary junction (CMJ) for facial pain remains largely uncharted. ObjectiveTo review outcomes with cervical and CMJ SCS performed by a single surgeon, with particular emphasis on complications and efficacy. MethodsAll patients that underwent cervical or CMJ SCS by the lead author were identified and follow-up obtained by telephone questionnaires. Patient demographics, surgical details, outcomes and complications for all patients identified were critically reviewed. ResultsOf 121 patients identified that underwent at least trial SCS, 100 underwent permanent lead implantation. Indications for cervical SCS included brachial plexus lesions (8), complex regional pain syndrome (33), degenerative disc disease (4), failed neck surgery syndrome (23), chronic radiculopathy (6) and post-herpetic neuralgia (PHN) (1); for CMJ SCS, indications included trigeminal deafferetiation pain (10), trigeminal neuropathic pain (4), PHN (4) and occipital neuralgia (7). Pain relief was greater along the extremities than axially, and less in the occipital area than in the head or face. Mean pain reduction averaged 56.6% at a mean follow-up of 4.2 years. Of 24 revision surgeries required, 8 were for presumed lead migration or fracture. Complications included 4 CSF leaks, 5 wound infections, and 4 cases of persistent numbness or pain. Pain relief lasted an average of 3.6 years. ConclusionCervical and CMJ SCS are safe and efficacious and may provide greater relief along the upper extremities than axially, and in the head rather than in the occipital region.

Spinal Cord Stimulation for Intractable Pain Evaluated by a Collision Study Using Somatosensory Evoked Potentials: A Preliminary Report

Appropriate stimulation of the dorsal column is required in order to achieve optimal control over pain by way of spinal cord stimulation (SCS). In this study, we objectively evaluated changes in somatosensory evoked potentials (SEPs) during a collision test in order to investigate whether paresthetic sensation or amount of pain reduction was correlated with the degree of dorsal column stimulation. We studied 12 patients with intractable pain who underwent permanent SCS implantation. SEP collision was examined while recording the cortical SEP components elicited by posterior tibial nerve stimulation. A positive collision effect was observed when the SEP amplitude was clearly reduced by the SCS. Based on the SEP collision findings, the effects of SCS were classified into four patterns: positive collision with pain reduction (Type 1), positive collision without pain reduction (Type 2), negative collision with pain reduction (Type 3), and negative collision without pain reduction (Type 4). Type 1 was observed for well-known diseases in which SCS was very effective, whereas Type 2 was seen in poor candidates for dorsal column stimulation. Patients with poststroke pain exhibited various patterns including types 1, 2, and 3. One patient showed Type 4 patterning, and we recommended further SCS trials before the abandonment of SCS therapy for this patient. We show that SEP collision is useful for evaluating the degree of dorsal column stimulation needed as well as in considering factors related to differences between responders and nonresponders to SCS therapy.

Device-Based Approaches to Modulate the Autonomic Nervous System and Cardiac Electrophysiology.

Alterations in resting autonomic tone can be pathogenic in many cardiovascular disease states, such as heart failure and hypertension. Indeed, autonomic modulation by way of beta-blockade is a standard treatment of these conditions. There is a significant interest in developing non-pharmacological methods of autonomic modulation as well. For instance, clinical trials of vagal stimulation and spinal cord stimulation in the treatment of heart failure are currently underway, and renal denervation has been studied recently in the treatment of resistant hypertension. Notably, autonomic stimulation is also a potent modulator of cardiac electrophysiology. Manipulating the autonomic nervous system in studies designed to treat heart failure and hypertension have revealed that autonomic modulation may have a role in the treatment of common atrial and ventricular arrhythmias as well. Experimental data on vagal nerve and spinal cord stimulation suggest that each technique may reduce ventricular arrhythmias. Similarly, renal denervation may play a role in the treatment of atrial fibrillation, as well as in controlling refractory ventricular arrhythmias. In this review, we present the current experimental and clinical data on the effect of these therapeutic modalities on cardiac electrophysiology and their potential role in arrhythmia management.

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

BackgroundThe 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...

Comparison of the visual analog scale (vas) and the scaling pain relief (spr) measurements in the assessment of the results of spinal cord stimulation trial and therapy: A prospective study

Objectives: The goal of this study was to compare the results of evaluating the success of spinal cord stimulation (SCS) using the Visual Analog Scale (VAS) and a Scaling Pain Relief (SPR) measurement. Methods: This prospective study included 29 patients, who were considered good candidates for an SCS trial. In the immediate post trial period, immediate post implant period, and one-month post implant period, pain relief was assessed by VAS percent change and using an SPR measurement (direct patient report of pain relief). Statistical analysis of the results included a repeated measures analysis of variance (ANOVA) comparing VAS percent change versus direct patient report of percentage of pain relief (SPR) at the post trial, post implant, and one month follow-ups for all patients that received a permanent implant. Results: Twenty-one patients had a successful trial and 20 were implanted with a permanent system. There was a strong positive correlation between the two pain relief measures at every measured timepoint. Direct patient reports of percentage of pain relief (SPR) were statistically higher than VAS percent change at the post trial period. Seven patients were considered good candidates for implantation based on the SPR measurement, but not VAS percent reduction. These patients went on to achieve clinically significant changes. Discussion: SPR measurements such as direct patient reports of pain relief should be considered in place of VAS percent change when determining SCS trial success.