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Lumbar spinal stenosis (LSS) is a common spinal disease of aging with a growing patient population, paralleling population growth. Minimally invasive treatments are evolving, and the use of these techniques needs guidance to provide the optimal patient safety and efficacy outcomes.The American Society of Pain and Neuroscience (ASPN) identified an educational need for guidance on the prudent use of the innovative minimally invasive surgical therapies for the treatment of symptomatic LSS. The executive board nominated experts spanning anesthesiology, physiatry, orthopedic surgery, and neurosurgery based on expertise, publications, research, diversity and field of practice. Evidence was reviewed, graded using the United States Preventive Services Task Force (USPSTF) criteria for evidence and recommendation strength and grade, and expert opinion was added to make consensus points for best practice.The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Scopus, and meeting abstracts to identify and compile the evidence (per section) for LSS-related pain. Search words were selected based upon the section represented. Identified peer-reviewed literature was critiqued using USPSTF criteria and consensus points are presented.The algorithm for patient selection in the management of symptomatic spinal stenosis is evolving. Careful consideration of patient selection and anatomic architecture variance is critical for improved outcomes and patient safety.ASPN created a guidance for best practice for minimally invasive surgical treatment of symptomatic spinal stenosis.

IntroductionInterventional pain procedures have increased in complexity, often requiring longer radiation exposure times and subsequently higher doses. The practicing physician requires an in-depth knowledge and evidence-based knowledge of radiation safety to limit the health risks to themselves, patients and healthcare staff. The objective of this study was to examine current radiation safety practices and knowledge among interventional pain physicians and compare them to evidence-based recommendations.Materials and methodsA 49-question survey was developed based on an extensive review of national and international guidelines on radiation safety. The survey was web-based and distributed through the following professional organizations: Association of Pain Program Directors, American Academy of Pain Medicine, American Society of Regional Anesthesia and Pain Medicine, European Society of Regional Anesthesia and Pain Therapy, International Neuromodulation Society, and North American Neuromodulation Society. Responses to radiation safety practices and knowledge questions were evaluated and compared with evidence-based recommendations. An exploratory data analysis examined associations with radiation safety training/education, geographical location, practice type, self-perceived understanding, and fellowship experience.ResultsOf 708 responding physicians, 93% reported concern over the health effects of radiation, while only 63% had ever received radiation safety training/education. Overall, ≥80% physician compliance with evidence-based radiation safety practice recommendations was demonstrated for only 2/15 survey questions. Physician knowledge of radiation safety principles was low, with 0/10 survey questions having correct response rates ≥80%.ConclusionWe have identified deficiencies in the implementation of evidence-based practices and knowledge gaps in radiation safety. Further education and training are warranted for both fellowship training and postgraduate medical practice. The substantial gaps identified should be addressed to better protect physicians, staff and patients from unnecessary exposure to ionizing radiation during interventional pain procedures.

Erythromelalgia is a rare neurovascular disorder characterized by erythema, warmth, and episodic burning pain, often felt in the face, hands, and feet. Symptoms are typically worse with heat, exercise, stress, and during the overnight hours. Management often requires a multidisciplinary approach, including pain trigger avoidance, cool water baths, and topical and oral neuropathic medications. The use of spinal cord stimulation has been described in multiple case reports with success reported out to 24 months. To our knowledge, the use of dorsal root ganglion (DRG) stimulation for erythromelalgia-related pain has not been described. Herein, we present a case of erythromelalgia-related pain at the bilateral plantar surfaces of the feet, which was treated successfully with bilateral sacral S1 nerve root DRG stimulation.

PURPOSE Peripheral nerve stimulation (PNS) is a rapidly expanding field within neuromodulation; however, there is limited data on therapeutic efficacy. This study describes the indications and clinical outcomes for patients undergoing PNS for chronic pain states. PATIENTS AND METHODS This is a retrospective case series of adults undergoing PNS implantation from 2004 to 2017 at an academic medical center. The primary outcomes were changes in numeric rating scale (NRS) pain scores, opioid utilization in oral morphine milligram equivalent (MME), and self-reported patient functioning at 6 months postoperatively. Infectious and device-related complications were also assessed. RESULTS A total of 72 patients underwent PNS implantation, including 59 patients that received a preceding PNS trial (59/78; 76% progression rate) and 13 that did not receive a PNS trial. The most common indication for stimulation was occipital neuralgia (47%) followed by lower-extremity neuropathies (17%). PNS implantation was associated with 6-month reductions in pain scores (7 [6, 8] baseline vs. 4 [2, 5] 6 months; P

Cancer and cancer treatment-related chronic pain affect a significant number of patients. The etiology of this pain is diverse and may include nociceptive and/or neuropathic characteristics. Treatment is often multifactorial and may require advanced interventional techniques, such as spinal cord stimulation (SCS). This narrative review provides a thorough overview of cancer-related pain mechanisms and the use of SCS for cancer-related pain. Additionally, a review of the precautions that should be considered when caring for this patient population is provided with recommendations for safe care when utilizing these techniques.

ObjectiveTo conduct a systematic literature review of dorsal root ganglion (DRG) stimulation for pain.DesignGrade the evidence for DRG stimulation.MethodsAn international, interdisciplinary work group conducted a literature search for DRG stimulation. Abstracts were reviewed to select studies for grading. General inclusion criteria were prospective trials (randomized controlled trials and observational studies) that were not part of a larger or previously reported group. Excluded studies were retrospective, too small, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsDRG stimulation has Level II evidence (moderate) based upon one high-quality pivotal randomized controlled trial and two lower-quality studies.ConclusionsModerate-level evidence supports DRG stimulation for treating chronic focal neuropathic pain and complex regional pain syndrome.

Background/objective Chronic pain is commonly reported in individuals with spinal cord injuries (SCIs), with recent prevalence reported as high as 80%. Uncontrolled pain is known to decrease quality of life, attenuate mood, and impact sleep. Spinal cord stimulation (SCS) for the treatment of refractory pain was first used in the SCI population in 1972. To date there have been no randomized controlled trials examining the effect of SCS on neuropathic pain post-SCI. A literature review in 2009 identified 27 studies, the majority prior to 2000, that included at least 1 patient with SCI. Given the significant advancements in the field of SCS, this review examines the updated evidence of SCS for the treatment of neuropathic pain in individuals with SCI and provides guidance on future investigations. Methods MEDLINE and EMBASE databases were searched. All published reports, case series, and clinical trials reviewing SCS for neuropathic pain that included at least 1 individual with SCI were included. Results The initial search identified 376 reports, of which 22 met inclusion criteria, for a total of 69 patients. All reports were of very low quality. A majority of the reported patients were male, underwent tonic stimulation, and reportedly experienced improvement in pain and spasticity, with decreased use of pain medication. Conclusions The synthesized findings from primarily case studies support the safety of SCS in SCI with the suggestion of potential pain relief benefit; however, data from low-quality studies are insufficient for informing clinical practice. A well-designed, prospective clinical trial is proposed to further investigate this indication.

Objective To synthesize the evidence regarding the effect of spinal stimulation (SS) vs medical therapy (MT) and the effect of newer SS technologies vs conventional SS on pain reduction in patients with intractable spine or limb pain. Methods A comprehensive literature search was conducted by a reference librarian. The literature search encompassed January 1, 1995 – December 31, 2017. Reviewers worked independently to select and appraise trials. Random-effect meta-analysis and frequentist indirect comparison methods were used to compare the three interventions. Results were expressed as odds ratio (OR) or weighted mean difference (WMD) with 95% CIs. Results We identified 12 trials enrolling 980 patients. Compared with MT, SS significantly increased the odds of reducing pain by 50% or more in three trials (OR, 13.01; 95% CI, 4.96-34.17) and significantly reduced pain as measured by visual analogue scale scores in three trials (WMD, 1.43 scale points; 95% CI, 0.16-2.71). Using the common comparator of MT, newer stimulation technology (eg, high-frequency 10 kilohertz spinal stimulation, Burst, dorsal root ganglion) was associated with increased odds of pain relief compared with conventional SS (OR, 2.07; 95% CI, 1.35-3.19). Conclusions In patients with intractable spine/limb pain, SS was associated with better pain reduction than MT. New stimulation technology was likely associated with better pain reduction than conventional stimulation.

Jonathan M Hagedorn, Nicholas Canzanello, Markus A Bendel, Thomas P Pittelkow, Tim J Lamer Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, 55905, USACorrespondence: Jonathan M HagedornDepartment of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, 55905, USAFax +1 507-266-7732Email jonhagedornmd@yahoo.comObjective: Surgical site infection in patients who undergo spinal cord stimulator implant surgery represents a significant concern in terms of increased health care costs and patient morbidity. The use of antibacterial envelopes in spinal cord stimulator implant surgeries has not been previously described. The aim of this retrospective review was to evaluate the effectiveness of the antibacterial envelope in reducing surgical site infection in spinal cord stimulator implant surgeries when used adjunctively to standard infection prevention measures.Materials and Methods: The study included 52 patients, all of whom were implanted with a spinal cord stimulator between January 2015 and November 2020. To be included, patients were required to have had an antibacterial envelope utilized at the time of surgery. Patient records were retrospectively reviewed. All patients who received an antibacterial envelope at the time of implant surgery were included.Results: Data was collected and analyzed on 52 permanent SCS implantations, including primary implantation (n=26) and revision surgery (n=26). All patients were at least three months post-operative from the implant surgery (average follow-up time period was 518.4 days). There were no surgical site infections reported in the 52 patient cohort.Conclusion: Antibiotic impregnated envelopes appear to be a safe and effective modality to decrease surgical site infection risk in spinal cord stimulation implant surgeries.Keywords: spinal cord stimulation, surgical site infection, outcomes, infection prevention

Cancer and cancer treatment-related chronic pain affect a significant number of patients. The etiology of this pain is diverse and may include nociceptive and/or neuropathic characteristics. Treatment is often multifactorial and may require advanced interventional techniques, such as spinal cord stimulation (SCS). This narrative review provides a thorough overview of cancer-related pain mechanisms and the use of SCS for cancer-related pain. Additionally, a review of the precautions that should be considered when caring for this patient population is provided with recommendations for safe care when utilizing these techniques.

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.

ObjectiveTo conduct a systematic literature review of peripheral nerve stimulation (PNS) for pain.DesignGrade the evidence for PNS.MethodsAn international interdisciplinary work group conducted a literature search for PNS. Abstracts were reviewed to select studies for grading. Inclusion/exclusion criteria included prospective randomized controlled trials (RCTs) with meaningful clinical outcomes that were not part of a larger or previously reported group. Excluded studies were retrospective, had less than two months of follow-up, or existed only as abstracts. Full studies were graded by two independent reviewers using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsPeripheral nerve stimulation was studied in 14 RCTs for a variety of painful conditions (headache, shoulder, pelvic, back, extremity, and trunk pain). Moderate to strong evidence supported the use of PNS to treat pain.ConclusionPeripheral nerve stimulation has moderate/strong evidence. Additional prospective trials could further refine appropriate populations and pain diagnoses.

ObjectiveTo conduct a systematic literature review of spinal cord stimulation (SCS) for pain.DesignGrade the evidence for SCS.MethodsAn international, interdisciplinary work group conducted literature searches, reviewed abstracts, and selected studies for grading. Inclusion/exclusion criteria included randomized controlled trials (RCTs) of patients with intractable pain of greater than one year’s duration. Full studies were graded by two independent reviewers. Excluded studies were retrospective, had small numbers of subjects, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsSCS has Level 1 evidence (strong) for axial back/lumbar radiculopathy or neuralgia (five high-quality RCTs) and complex regional pain syndrome (one high-quality RCT).ConclusionsHigh-level evidence supports SCS for treating chronic pain and complex regional pain syndrome. For patients with failed back surgery syndrome, SCS was more effective than reoperation or medical management. New stimulation waveforms and frequencies may provide a greater likelihood of pain relief compared with conventional SCS for patients with axial back pain, with or without radicular pain.

Facet joint steroid injections are used to treat chronic low back pain. However, little is known about the systemic absorption and serum levels of steroids following intra-articular facet joint injections. The primary objective of this preliminary study was to investigate the pharmacokinetics of triamcinolone acetonide following fluoroscopically guided intra-articular lumbar facet joint injections in a cohort of patients with chronic low back pain. A secondary aim was to investigate the effects of triamcinolone on serum cortisol levels following lumbar facet joint injections.The study cohort included 5 patients undergoing fluoroscopically guided intra-articular lumbar facet joint injections at a pain medicine specialty clinic. Blood was collected prior to the injections and on days 1, 2, 4, 6, 8, 14, 21, 28, 35, and 42 following the injections.The terminal elimination half-life of triamcinolone in a noncompartmental analysis was 213 hours. The peak median triamcinolone concentration of 3.6 ng/mL was detected within 24 hours after the injections. Serum cortisol levels were30 ng/mL for an average of 4.4 days. The maximum effect of triamcinolone on cortisol suppression was observed with triamcinolone serum levels of1.9 ng/mL.The peak serum concentration of triamcinolone following intra-articular facet joint injections occurred within 24 hours. The median terminal elimination half-life was 213 hours, but baseline cortisol levels were suppressed for an average of 4.4 days. Clinically, the prolonged half-life and endocrine effects of triamcinolone could increase the risk for serious drug-drug interactions in patients taking medications that inhibit corticosteroid metabolism.

Objective The goal of this study was to determine the frequency and clinical indications associated with implantation of single versus dual percutaneous lead spinal cord stimulator (SCS) systems and to look further into how these leads are utilized for treatment. Materials and Methods A retrospective cohort analysis of all patients undergoing SCS implantation between January 2001 and December 2013 with a minimum of two year clinical follow-up was performed. Number of trial and implanted leads was recorded. For patients with dual lead systems, it was noted if and when the second lead was used, along with the clinical indication for lead activation. Results Of the 259 patient cohort, 15.8% (n=41) patients underwent placement of a single lead system, 83.0% (n=215) underwent placement of a dual lead system, and 1.2% (n=3) underwent placement of three lead systems. Placement of dual lead systems was similar among all indication groups. Of those patients with a dual lead system in place, 88.1% utilized both leads and average time to programming of the second lead was 2.3 months. Most common reason to activate the second lead was inadequate stimulation coverage. Five of the 41 patients with single-lead systems underwent an additional surgery to implant a second lead due to inadequate stimulation with one lead. Conclusions To our knowledge this is the first descriptive analysis of the frequency of single and dual lead spinal cord stimulator systems. This report indicates that dual lead systems are most often placed and both leads are required for optimal patient therapy. This article is protected by copyright. All rights reserved.

Introduction Intrathecal drug delivery systems (IDDSs) have dramatically improved analgesia and the functional status of cancer patients and those with chronic pain states. However, given the close proximity to the neuraxis and frequent concomitant use of antiplatelet or anticoagulant medications, this intervention is not without risk. The goal of this investigation was to determine the incidence of bleeding complications following IDDS placement. Methods This is a retrospective review from 2005 through 2014 of adult patients undergoing IDDS implantation or revision at a tertiary care center. The primary outcome was a bleeding-related neurological complication requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. Results A total of 247 procedures were performed on 216 unique patients. Patients received aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) within seven days of needle placement for 64 procedures (25.9%). A preprocedural platelet count or international normalized ratio (INR) was available within 30 days for 138 procedures (55.9%). Of these, two patients had a platelet count lower than 100 x 109/L and one patient had an INR of 1.5 or higher at the time of the procedure. One neurological complication was identified (0.4%) that was not related to procedural bleeding. Similarly, three patients (1.2%) received a periprocedural red blood cell transfusion, none of which were related to procedural bleeding. Conclusion No cases of bleeding-related neurological complications were identified following IDDS placement or revision, including in those receiving aspirin or NSAIDs. Future investigations with larger numbers are needed to further explore the safety of antithrombotic therapy continuation or discontinuation periprocedurally.

Introduction Intrathecal therapy is an important part of the pain treatment algorithm for chronic disease states. The use of this option is a viable treatment strategy, but it is inherent for pain physicians to understand risk assessment and mitigation. In this manuscript, we explore evidence and mitigating strategies to improve safety with intrathecal therapy. Methods A robust literature search was performed covering January 2011 to October 9, 2016, in PubMed, Embase, MEDLINE, Biomed Central, Google Scholar, Current Contents Connect, and International Pharmaceutical Abstracts. The information was cross-referenced and compiled for evidence, analysis, and consensus review, with the intent to offer weighted recommendations and consensus statements on safety for targeted intrathecal therapy delivery. Results The Polyanalgesic Consensus Conference has made several best practice recommendations to improve care and reduce morbidity and mortality associated with intrathecal therapy through all phases of management. The United States Prevention Service Task Force evidence level and consensus strength assessments are offered for each recommendation. Conclusion Intrathecal therapy is a viable and relatively safe option for the treatment of cancer- and noncancer-related pain. Continued research and expert opinion are required to improve our current pharmacokinetic and pharmacodynamic model of intrathecal drug delivery, as this will undoubtedly improve safety and efficacy.

Background and Objectives Interventional pain procedures are commonly performed on patients receiving antiplatelet therapy. However, there is limited evidence to support or refute the safety of this practice. The goal of this investigation was to assess the rate of bleeding complications in a large cohort of patients undergoing intermediate- and low-risk pain procedures, with a specific focus on antiplatelet and anticoagulant medication use and baseline coagulation abnormalities. Methods This is a retrospective cohort study of adult patients undergoing low- and intermediate-risk pain procedures from 2005 through 2014 by the division of pain medicine at a single academic tertiary care center. Baseline characteristics, antiplatelet and anticoagulant medication use, coagulation parameters, and procedural details were extracted from the electronic medical record. The primary outcome was a bleeding-related complication requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. The secondary outcome was the presence or absence of a periprocedural red blood cell transfusion occurring within 72 hours of needle placement. Results A total of 58,066 procedures were performed on 24,590 unique patients. Preprocedural aspirin or nonsteroidal anti-inflammatory drug therapy was present for 17,825 procedures (30.7%). Sixteen procedures were associated with perioperative red blood cell transfusion (0.03%), with no difference based on preprocedural nonsteroidal anti-inflammatory drug, including aspirin, or other anticoagulation use (P = 0.107). Five patients (0.009%) had a neurologic complication requiring further evaluation, of which 2 were likely related to procedural bleeding. Conclusions Bleeding complications are rare in patients undergoing low- or intermediate-risk pain procedures even in the presence of antiplatelet medications. This is consistent with recently released guidelines.

Introduction Neurostimulation involves the implantation of devices to stimulate the brain, spinal cord, or peripheral or cranial nerves for the purpose of modulating the neural activity of the targeted structures to achieve specific therapeutic effects. Surgical placement of neurostimulation devices is associated with risks of neurologic injury, as well as possible sequelae from the local or systemic effects of the intervention. The goal of the Neurostimulation Appropriateness Consensus Committee (NACC) is to improve the safety of neurostimulation. Methods The International Neuromodulation Society (INS) is dedicated to improving neurostimulation efficacy and patient safety. Over the past two decades the INS has established a process to use best evidence to improve care. This article updates work published by the NACC in 2014. NACC authors were chosen based on nomination to the INS executive board and were selected based on publications, academic acumen, international impact, and diversity. In areas in which evidence was lacking, the NACC used expert opinion to reach consensus. Results The INS has developed recommendations that when properly utilized should improve patient safety and reduce the risk of injury and associated complications with implantable devices. Conclusions On behalf of INS, the NACC has published recommendations intended to reduce the risk of neurological injuries and complications while implanting stimulators.

Baastrup disease is a condition where spinous processes form painful pseudoarticulations. We present a patient with midline axial back pain consistent with Baastrup disease confirmed by computed tomography, which revealed degenerative changes along the opposing surfaces of the spinous processes at L1-2 and L2-3. Local anesthetic and steroid interspinous injections lost their effectiveness over time. She underwent successful interspinous radiofrequency lesioning, which has not been previously described in the literature. At 4 months follow-up, she reported complete pain relief.

ObjectiveSpinal cord stimulation (SCS) is an evidence-based therapy for the treatment of refractory pain. Current American College of Graduate Medical Education requirements for pain medicine fellowship graduation include observation of five neuromodulation cases. Matriculating fellows have varying degrees of technical skill, training, and experience. The purpose of this study was to use an innovative skill-based assessment tool using the validated Zwisch scale to evaluate fellow surgical performance during SCS cases.DesignCross-sectional surveySettingMayo Clinic, Rochester, Minnesota.SubjectsConsultant faculty (10) in the Division of Pain Medicine and pain medicine fellows (5).MethodsA list of faculty-driven neuromodulation surgical objectives was formed and a rubric was created that focused on technical approach, imaging, epidural access and wound closure. Consultants who perform surgical cases were instructed to use the Zwisch scale as a guide to evaluate fellow surgical performance during a neuromodulation case. Faculty and fellows were surveyed before and after implementation of the tool to determine their satisfaction with use of the skill assessment tool.ResultsThe consultants reported they were more satisfied, consistent, and efficient with feedback provided to the trainee on every aspect of neuromodulation surgical cases. The improvement was most significant during the fellows’ intraoperative skill assessment. The fellows indicated increased satisfaction, improved communication, and increased efficiency of feedback when the tool was utilized. The fellows reported greater intraoperative skill assessment and consistency of feedback provided.ConclusionsThe diverse nature of primary specialty backgrounds observed in pain medicine fellowship training offers a unique opportunity to assess and improve fellow skill and surgical competence in the field of neuromodulation. Both faculty and fellows reported improved satisfaction, consistency and efficiency with feedback provided. Importantly, this pilot project observed that implementation of a skill assessment tool was beneficial for both the faculty and fellow as the feedback received was viewed as strongly beneficial to the educational experience.

Introduction The approach to intrathecal (IT) drug delivery malfunction is complicated, particularly for iodine-allergic patients. In these situations, the current literature has not addressed the use of IT gadolinium. Case reports exist showing severe neurotoxic manifestations with IT gadolinium use. We sought to provide a resource for chronic pain physicians treating an iodine-allergic patient and considering the use of IT gadolinium. Methods A thorough literature search identified 11 published cases of gadolinium-induced neurotoxicity due to IT injection and those cases are described in detail. The literature was also reviewed for safe dosages of IT gadolinium. Results After thorough review, a safe IT gadolinium dose is provided. Additionally, an algorithm was developed for the workup of an IT pump malfunction in iodine allergic patients. Conclusion Herein, we provide guidance on IT gadolinium usage and a framework for IT pump malfunction in iodine allergic patients.

All neuromodulation device operations are elective procedures. Accordingly, it is essential for referring practitioners and implanting practitioners to thoroughly understand the risks and that the implanting practitioner is aware of and utilizes the most up-to-date risk mitigation protocols and procedures. The most serious complications are those that lead to neurological injury and, fortunately, are rare. On the other hand the more commonly occurring complications and adverse events such as lead migration or fracture, hardware-related pain or discomfort, and aberrant stimulation are distressing to the patient, frustrating for the implanting practitioner, and often lead to increased costs since these scenarios may require repeated office visits and even hardware revision to adequately treat or resolve the problem. This chapter will discuss the most common and serious complications and adverse events associated with neuromodulation devices.

Background New advances in spinal cord stimulation have led to improved treatment of patients suffering from chronic pain. While the overall safety of newer stimulation devices has been established, no published reports exist regarding safety considerations when these devices are implanted in patients with a preexisting cardiac device. Case report An 83-year-old man with a history of out-of-hospital cardiac arrest secondary to an episode of ventricular fibrillation underwent automated implantable cardiac defibrillator placement. Concomitantly, he suffered from intractable chronic low axial back pain and was deemed a candidate for high-frequency (10 kHz) spinal cord stimulation (SCS). Cardiac monitoring during SCS trial and implantation was performed with no interference noted. Following high-frequency SCS implantation, the patient was observed to have significant pain relief with functional improvement. Discussion While others have reported safety during traditional SCS in patients with implanted cardiac devices, this is the first case report to describe safe and effective use of high-frequency SCS in a patient with an implanted cardiac device.

Introduction. 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. Methods. 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. Results. 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. Conclusion. 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.

Objective. The purpose of this study was to determine whether the energy generated by an active radiofrequency (RF) cannula adjacent to lumbar spine hardware could result in heating of the hardware. Design. Prospective study. Setting. Tertiary care medical center. Subjects. Six patients with lumbar facet joint pain at the level adjacent to lumbar spine fusion hardware were studied. Methods. A total of 10 lumbar medial branch nerve radiofrequency lesion procedures were performed on six patients. A temperature probe was placed on the fusion hardware to continuously monitor the temperature of the hardware throughout the RF procedure. Results. The temperature of the fusion hardware increased in six of the 10 RF lesion procedures. During two of the procedures, the temperature rose rapidly to 42°C, at which time the procedure was ceased at that level. Conclusion. This study demonstrated that radiofrequency lesioning to treat symptomatic facet joint pain in patients who have adjacent posterior lumbar fusion hardware may result in heat energy being transferred to the adjacent hardware. This may increase the risk of injury to the patient. Monitoring for a temperature increase is easily accomplished by inserting a temperature probe onto the surface of the hardware.

Middle cluneal nerve entrapment neuropathy/neuralgia (MCN-EN) is a rare and potentially underdiagnosed etiology for chronic low back pain. Symptoms include pain in the buttock and posterior superior iliac spine area that is increased by activity and direct pressure over the area, and is "neuropathic" in nature. Previous case reports describe successful treatment of MCN-EN with nerve block and/or surgical decompression of the MCN. We present a case report detailing the first successful use of radiofrequency nerve ablation in treating MCN-EN.

Celiac plexus neurolysis has been shown to be an effective analgesic option for patients with visceral pain related to intraabdominal malignancies. In the setting of significant tumor burden, the celiac plexus may be inaccessible, limiting the efficacy of the transcrural approach. This case report describes a novel single-needle approach to retrocrural celiac plexus blockade, allowing for rapid blockade with a needle trajectory contralateral to the aorta in a 73-year-old woman with altered anatomy secondary to advanced metastatic colorectal cancer.

Objective: To synthesize the evidence regarding the effect of spinal cord stimulation (SCS) on opioid and pain medication reduction in patients with intractable spine or limb pain. Methods: A comprehensive literature search was conducted to identify RCTs of patients with chronic back and/or limb pain of greater than one year duration. Only comparative studies were included (ie, conventional SCS vs medical therapy, conventional SCS vs high-frequency SCS) and were required to have a minimum follow-up period of 3 months. Random effect meta-an alysis was used to compare the three interventions. Results were expressed as odds ratio (OR) or weighted mean difference (WMD) with 95% confidence intervals (CI). Results: We identified five trials enrolling 489 patients. Three of the trials reported the results as a number of patients who were able to reduce or eliminate opioid consumption in the SCS vs medical therapy group. The odds of reducing opioid consumption were significantly increased in the SCS group compared to medical therapy (OR 8.60, CI {1.93-38.30}). Two of the trials reported the results as mean medication dose reduction as measured by the Medication Quantification Scale (MQS) in the SCS group vs medical therapy group. MQS score significantly decreased in the SCS group and not in the medical group (WMD -1.97, 95% CI {-3.67, -0.27}). One trial reported a number of patients in high-frequency SCS who were able to reduce opioids vs number of patients in conventional SCS group who were able to reduce opioids. Thirty-four percent of the patients in the high-frequency group and 26% of the patients in the conventional SCS group were able to reduce opioid consumption; however, there was not a significant difference between groups (OR 1.43, 95% CI {0.74, 2.78}). This trial also quantified the opioid reduction in morphine equivalent dosage (MED). In the high-frequency SCS group, average MED decreased by 24.8 mg vs average MED decrease of 7.3 mg in the conventional SCS group. Again, the difference between groups did not reach statistical significance (-17.50, CI {-66.27, 31.27}). Conclusions: In patients with intractable spine/limb pain, SCS was associated with increased odds of reducing pain medication consumption. However, results should be treated with caution as available data were limited, and clinical significance of these findings requires further study.

Background Lumbar spinal stenosis (LSS) can lead to compression of neural elements and manifest as low back and leg pain. LSS has traditionally been treated with a variety of conservative (pain medications, physical therapy, epidural spinal injections) and invasive (surgical decompression) options. Recently, several minimally invasive procedures have expanded the treatment options. Methods The Lumbar Spinal Stenosis Consensus Group convened to evaluate the peer-reviewed literature as the basis for making minimally invasive spine treatment (MIST) recommendations. Eleven consensus points were clearly defined with evidence strength, recommendation grade, and consensus level using U.S. Preventive Services Task Force criteria. The Consensus Group also created a treatment algorithm. Literature searches yielded 9 studies (2 randomized controlled trials [RCTs]; 7 observational studies, 4 prospective and 3 retrospective) of minimally invasive spine treatments, and 1 RCT for spacers. Results The LSS treatment choice is dependent on the degree of stenosis; spinal or anatomic level; architecture of the stenosis; severity of the symptoms; failed, past, less invasive treatments; previous fusions or other open surgical approaches; and patient comorbidities. There is Level I evidence for percutaneous image-guided lumbar decompression as superior to lumbar epidural steroid injection, and 1 RCT supported spacer use in a noninferiority study comparing 2 spacer products currently available. Conclusions MISTs should be used in a judicious and algorithmic fashion to treat LSS, based on the evidence of efficacy and safety in the peer-reviewed literature. The MIST Consensus Group recommend that these procedures be used in a multimodal fashion as part of an evidence-based decision algorithm.

To synthesize the evidence regarding the effect of spinal stimulation (SS) vs medical therapy (MT) and the effect of newer SS technologies vs conventional SS on pain reduction in patients with intractable spine or limb pain.A comprehensive literature search was conducted by a reference librarian. The literature search encompassed January 1, 1995 - December 31, 2017. Reviewers worked independently to select and appraise trials. Random-effect meta-analysis and frequentist indirect comparison methods were used to compare the three interventions. Results were expressed as odds ratio (OR) or weighted mean difference (WMD) with 95% CIs.We identified 12 trials enrolling 980 patients. Compared with MT, SS significantly increased the odds of reducing pain by 50% or more in three trials (OR, 13.01; 95% CI, 4.96-34.17) and significantly reduced pain as measured by visual analogue scale scores in three trials (WMD, 1.43 scale points; 95% CI, 0.16-2.71). Using the common comparator of MT, newer stimulation technology (eg, high-frequency 10 kilohertz spinal stimulation, Burst, dorsal root ganglion) was associated with increased odds of pain relief compared with conventional SS (OR, 2.07; 95% CI, 1.35-3.19).In patients with intractable spine/limb pain, SS was associated with better pain reduction than MT. New stimulation technology was likely associated with better pain reduction than conventional stimulation.

Pain medicine has become increasingly surgical in its focus. Our progression from medication management and conventional injections to advanced procedures and minimally invasive surgical management of chronic pain requires updated training paradigms. While some programs have adapted over time to

Introduction Spinal cord stimulators (SCS) are used to treat various chronic pain states. Establishing patient outcomes in terms of pain control, opioid medication use, and overall satisfaction is vital in maintaining SCS's role in clinical practice. Methods All patients who underwent SCS implantation between January 2001 and December 2011 at a tertiary academic pain medicine center were included if he or she underwent permanent cervical or thoracolumbar dorsal column SCS implantation and age was 18 or greater. For the 199 patients who met inclusion criteria, data were collected retrospectively. Preimplant information included indication for implantation, Numeric Rating Scale (NRS) score, and dose in oral morphine equivalents (OME). Postimplant NRS score was recorded at 6 months and 1 year. OME requirement and patient satisfaction were determined at 1 year postimplantation. Results This data set showed an overall decrease in OME requirements and NRS scores at both 6 months and 1 year. These differences were statistically significant (P

Objective To determine whether the thermal energy associated with lumbar spine radiofrequency neurotomy (RFN) performed near titanium and stainless steel pedicle screws is conducted to the pedicle screws or adjacent tissues, or both, thus introducing potential for thermal damage to those tissues. Design Cadaver study. Setting Cadaver laboratory equipped with fluoroscopy, surgical spine implements, and radiofrequency generator. Subjects No live human subject; a fresh frozen (and thawed) cadaver torso was used for the study. Methods Titanium and stainless steel pedicle screws were placed in the lumbar spine of a fresh frozen cadaver torso with real-time fluoroscopic guidance. Conventional RFN cannula placement was performed at the level of pedicle screws and a control (nonsurgically altered) lumbar level. Neurotomy was performed with conventional radiofrequency lesioning parameters. Temperatures were recorded at multiple sites through thermistor probes. Results Direct contact of the radiofrequency cannula with the pedicle screws during conventional RFN produced a substantial increase in temperature in the surrounding soft tissues. A small increase in temperature occurred at the same sites at the control level. Conclusions Titanium and stainless steel pedicle screws are capable of sustaining large increases in temperature when the radiofrequency probe comes in contact with the screw. These results are suggestive that pedicle screws could serve as a possible source of tissue heating and thermal injury during RFN.

Objectives Opioid treatment of chronic noncancer pain (CNCP) adds complexity and uncertainty to patient interactions. We sought to assess clinician attitudes, beliefs, practice styles, and concerns around opioid prescribing following the release of the US Centers for Disease Control and Prevention (CDC) guideline for prescribing opioids for chronic pain. Methods E-mailed electronic survey to clinicians at a large academic medical institution. Results A total of 961 clinicians responded to the survey (response rate = 40%), 720 of whom prescribed opioids and were not in training. Sixty-five percent were physicians, and 35% were nurse practitioners or physician assistants, with a mean age of 47 years (SD ± 11.4 years). Eighty-two percent were reluctant to prescribe opioids for CNCP, and only 47% expressed confidence in their care for CNCP patients. Sixty-seven percent were aware of the CDC guideline, 55% were enrolled in the state Prescription Drug Monitoring Program (PDMP), and 2% always or frequently prescribed naloxone to patients on opioids. Guideline awareness was associated with increased confidence in caring for CNCP patients. Clinicians having knowledge of a patient overdose were 31% more likely to be enrolled in the PDMP (relative rate= 1.31, 95% confidence interval = 1.14-1.52, chi-square = 11.00, P

Objective Intra-articular injections of the C1–2 joint are an effective therapeutic option for pain generated from degenerative and inflammatory conditions affecting the joint. Limited information exists about the adverse events (AEs) associated with these injections. The primary aim of this study is to describe the frequency and type of AEs associated with C1–2 joint injections. The secondary aim is to identify clinical factors associated with the occurrence of AEs of C1–2 joint injections. Design/methods A retrospective chart review was conducted on all C1–2 joint injections performed at the Mayo Pain Medicine Clinic in Rochester, MN, from January 1, 2005 through July 31, 2015. AE data were extracted from procedural and post-procedural clinical notes. Analysis was conducted to determine correlations between any AE and demographic and clinical characteristics. Using univariate and multivariate logistic regression analyses, associations were determined. Results From January 1, 2005 to July 31, 2015, 135 C1–2 injections were performed on 72 patients. Overall, at least 1 AE was reported in 18.5% of the injections. The most common AEs were post-procedural increase in pain and procedural vascular contrast uptake. There was a significant association between AE occurrence and greater pre-procedural maximum pain score. Conclusions AEs from C1–2 joint injections occurred commonly, but there were no persistent or serious AEs associated with these injections. The data also demonstrate that patients with higher pre-procedural maximum pain scores are more likely to experience an AE.

Background context The objective of the North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Lumbar Disc Herniation with Radiculopathy is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of lumbar disc herniation with radiculopathy. The guideline is intended to reflect contemporary treatment concepts for symptomatic lumbar disc herniation with radiculopathy as reflected in the highest quality clinical literature available on this subject as of July 2011. The goals of the guideline recommendations are to assist in delivering optimum efficacious treatment and functional recovery from this spinal disorder. Purpose To provide an evidence-based educational tool to assist spine specialists in the diagnosis and treatment of lumbar disc herniation with radiculopathy. Study design Systematic review and evidence-based clinical guideline. Methods This guideline is a product of the Lumbar Disc Herniation with Radiculopathy Work Group of NASS' Evidence-Based Guideline Development Committee. The work group consisted of multidisciplinary spine care specialists trained in the principles of evidence-based analysis. A literature search addressing each question and using a specific search protocol was performed on English-language references found in Medline, Embase (Drugs and Pharmacology), and four additional evidence-based databases to identify articles. The relevant literature was then independently rated using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final recommendations to answer each clinical question were developed via work group discussion, and grades were assigned to the recommendations using standardized grades of recommendation. In the absence of Level I to IV evidence, work group consensus statements have been developed using a modified nominal group technique, and these statements are clearly identified as such in the guideline. Results Twenty-nine clinical questions were formulated and addressed, and the answers are summarized in this article. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence. Conclusions The clinical guideline has been created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with symptomatic lumbar disc herniation with radiculopathy. The entire guideline document, including the evidentiary tables, suggestions for future research, and all the references, is available electronically on the NASS Web site at http://www.spine.org/Pages/PracticePolicy/ClinicalCare/ClinicalGuidlines/Default.aspx and will remain updated on a timely schedule.

Objective To examine the incidence of percutaneous spinal cord stimulator lead migration, given current hardware and surgical technique. Materials and Methods We retrospectively reviewed records of patients who underwent spinal cord stimulator implantation with percutaneous leads at our institution from 2008 through 2011. We determined the number of patients who required surgical revision for clinically significant lead migration. Results Clinically significant lead migration requiring surgical revision occurred in three of 143 patients (2.1%) with primary SCS system implants utilizing percutaneous-type leads. Conclusions The rate of lead migration observed in our practice was considerably lower than previously published estimates of clinically significant lead migration or revision for lead migration (13%–22%). However, our study did not determine the reason for the decreased rate, which may be influenced by current hardware and implant techniques.

Our purpose was to determine the incidence of surgical site infection (SSI) in cancer patients receiving an intrathecal drug delivery system (IDDS) and compare that rate with the incidence of SSI in the general population receiving an IDDS or spinal cord stimulator. We attempted to describe risk factors for SSIs in cancer patients treated with IDDS in terms of exposure to cancer treatments.Retrospective review.Large tertiary care center.Cancer patients receiving an IDDS in 2006-2013.The incidence of SSI was determined according to the US Centers for Disease Control and Prevention definition. Medication regimens and current cancer treatment were investigated to identify immunocompromised patients during IDDS placement. Microbacteriology, treatment, and overall outcomes were investigated.Sixty-four patients had an IDDS implanted in 2006-2013. SSI developed in four patients (6.2%). All four patients had received chemotherapy or radiotherapy within three months before implantation. Three of the three were receiving dexamethasone, and three of the four required explantation of the IDDS.The incidence of SSI was at the upper end of the published infection rates for IDDS. The risk of SSI may be increased in this population because of factors that alter the patient's immune status, including concomitant corticosteroid use, radiotherapy near the SSI, and presence of immunomodulators. The identification and mitigation of certain risk factors for this population may prevent infection in future patients.

Background and Objectives Celiac plexus blockade has known risks including bleeding and neurologic injury because of the close proximity of vascular and neuraxial structures. The aim of this study was to determine the incidence of bleeding complications in patients undergoing celiac plexus block (CPB), with an emphasis on preprocedural antiplatelet medication use and coagulation status. Methods This is a retrospective study from 2005 to 2014 of adult patients undergoing CPB by the pain medicine division at a tertiary care center. The primary outcome was red blood cell (RBC) transfusion within 72 hours of needle placement, with a secondary outcome of bleeding complications requiring emergency medicine, neurology, or neurosurgical evaluation within 31 days. Results A total of 402 procedures were performed on 298 unique patients, with 58 patients (14.4%) receiving aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) preoperatively. Five patients (1.2%) received RBC transfusion within 72 hours, of which one had received preprocedure NSAIDs. A platelet count measured within 30 days was available for 268 patients, with 7 patients (2.6%) having platelet counts of 100 × 109/L or less at the time of needle placement. A total of 187 patients had a valid preoperative international normalized ratio (INR), with 9 (4.8%) having an INR of 1.5 or higher (range, 1.5–2.6). One patient (11.1%) required RBC transfusion compared with an RBC transfusion rate of 2.3% (4 of 178) in those with normal INR (P = 0.221). We identified no bleeding complications requiring emergency medicine, neurology, or neurosurgical evaluation. Conclusions This study suggests that CPBs may be safely performed in patients receiving aspirin and/or NSAID therapy.

Introduction Intrathecal (IT) drug infusion is an appropriate and necessary tool in the algorithm to treat refractory cancer and noncancer pain. The decision-making steps/methodology for selecting appropriate patients for implanted targeted drug delivery systems is controversial and complicated. Therefore, a consensus on best practices for determining appropriate use of IT drug infusion may involve testing/trialing this therapy before implantation. Methods This current Polyanalgesic Consensus Conference (PACC) update was designed to address the deficiencies and emerging innovations since the previous PACC convened in 2012. A literature search identified publications available since the previous PACC publications in 2014, and relevant sources were contributed by the PACC members. After reviewing the literature, the panel determined the evidence levels and degrees of recommendations. The developed consensus was ranked as strong (>80%), moderate (50-79%), or weak ( Results The trialing for IT drug delivery systems (IDDS) remains an area of continued controversy. The PACC recommendations for trialing are presented in 34 consensus points and cover trialing for morphine, ziconotide, and medication admixtures; starting doses and titration practices; measurements of success; trial settings and monitoring; management of systemic opioids during trialing; and the role of psychological evaluation. Finally, the PACC describes clinical scenarios in which IT trialing is required or not required. Conclusion The PACC provides consensus guidance on best practices of trialing for IDDS implants. In addition, the PACC recommends that no trial may be required in certain patient populations.

Neural stimulation is increasingly used as a treatment for chronic pain. Common indications for spinal cord stimulation include chronic neuropathic and oncological pain, intractable angina, or chronic pain secondary to vascular disease. It is estimated that up to 4 million patients may be candidates for the therapy. Therefore, it is likely that an increasing number of patients will have spinal neurostimulation devices implanted over the coming years. Because radiography and computed tomography are the primary imaging modalities used to evaluate the proper positioning of these devices, radiologists should be familiar with their appearance. The purpose of this article is to discuss the types of neurostimulation devices currently being used and to demonstrate their respective imaging appearances.

Background Lumbar interlaminar epidural steroid injections (ESIs) are one of the most commonly performed procedures in pain medicine, but little is known about the serum levels of steroids following injection into the epidural space. The primary objective of this study was to investigate the pharmacokinetics of fluoroscopy-guided epidural-administered triamcinolone acetonide in a cohort of patients with chronic low-back pain seeking treatment in a pain medicine clinic. Methods The study cohort included 10 patients undergoing a fluoroscopically guided L4-L5 or L5-S1 lumbar interlaminar ESI at a pain medicine specialty clinic. Blood was collected prior to the ESI and on days 1, 2, 4, 6, 8, 14, 21, 28, 35, and 42 following the injection. The sample extract was analyzed by tandem mass spectrometry. Results The terminal elimination half-life of epidural-administered triamcinolone in a noncompartmental analysis was 523 hours. In the noncompartmental analysis, peak triamcinolone concentrations of 4.1 ng/mL were detected within 24 hours after administration. Conclusions The pharmacokinetics of epidural-administered triamcinolone is consistent with previously observed adverse effects of the drug on endocrine function. The pharmacokinetics of other epidural-administered steroids should be determined and incorporated in clinical trials to investigate the potential associations between serum levels, clinical outcomes, and potential adverse endocrine effects.