Improved Pain Control with Combination Spinal Cord Stimulator Therapy Utilizing Sub-perception and Traditional Paresthesia Based Waveforms: A Pilot Study.

BACKGROUND: Chronic back and neck pain affects 20% of Americans. Spinal cord stimulation (SCS) is an effective therapy for otherwise refractory chronic pain. Traditional SCS relies on low-frequency stimulus in the 40 - 60 Hz range causing robust paresthesia in regions overlapping with painful dermatomes. OBJECTIVES: This study aims to determine the effect of superimposing sub-perception stimulation in patients who previously had good long-term relief with paresthesia. METHODS: This is a prospective observational trial examining patients who had previously been implanted with paresthesia based SCS for failed back surgery syndrome (FBSS) or complex regional pain syndrome (CRPS). These patients presented for implantable pulse generator (IPG) replacement based on battery depletion with an IPG capable of combined sub-perception and paresthesia based SCS therapy. Patients were assessed immediately following the exchange and four weeks later using a telephone survey. Their pain was assessed on each follow up using a Numerical Rating scale (NRS); the primary outcome was the change in NRS after four weeks from the exchange day. Secondary outcomes included paresthesia changes, which included the subjective quality of sensation generated, the overall subjective coverage of the painful region, subjective variation of coverage with positional changes, and global perception of the percentage improvement in pain. RESULTS: Based on our clinic registry, 30 patients were eligible for IPG exchange, 16 were consented for follow up and underwent an exchange, and 15 were available for follow up four weeks following. The average NRS decreased from 7.47 with traditional SCS to 4.5 with combination therapy. 80% of patients reported an improvement in the quality of paresthesia over traditional SCS therapy, and in most patients, this translated to significantly improved pain control. CONCLUSIONS: Our findings suggest improved pain relief in patients who had previously had good results with paresthesia based therapy and subsequently underwent IPG exchange to a device capable of delivering combined sub-perception stimulation. The mechanism of action is unclear though there may be an additive and/or synergistic effect of the two waveforms delivered. Larger studies with long-term follow-up are needed to elucidate the durability of pain relief and the precise mechanism by which combined subperception and paresthesia based SCS may improve overall patient outcomes.

Epidural Interventions in the Management of Chronic Spinal Pain: American Society of Interventional Pain Physicians (ASIPP) Comprehensive Evidence-Based Guidelines.

BACKGROUND: Chronic spinal pain is the most prevalent chronic disease with employment of multiple modes of interventional techniques including epidural interventions. Multiple randomized controlled trials (RCTs), observational studies, systematic reviews, and guidelines have been published. The recent review of the utilization patterns and expenditures show that there has been a decline in utilization of epidural injections with decrease in inflation adjusted costs from 2009 to 2018. The American Society of Interventional Pain Physicians (ASIPP) published guidelines for interventional techniques in 2013, and guidelines for facet joint interventions in 2020. Consequently, these guidelines have been prepared to update previously existing guidelines. OBJECTIVE: To provide evidence-based guidance in performing therapeutic epidural procedures, including caudal, interlaminar in lumbar, cervical, and thoracic spinal regions, transforaminal in lumbar spine, and percutaneous adhesiolysis in the lumbar spine. METHODS: The methodology utilized included the development of objective and key questions with utilization of trustworthy standards. The literature pertaining to all aspects of epidural interventions was viewed with best evidence synthesis of available literature and  recommendations were provided. RESULTS: In preparation of the guidelines, extensive literature review was performed. In addition to review of multiple manuscripts in reference to utilization, expenditures, anatomical and pathophysiological considerations, pharmacological and harmful effects of drugs and procedures, for evidence synthesis we have included 47 systematic reviews and 43 RCTs covering all epidural interventions to meet the objectives.The evidence recommendations are as follows: Disc herniation: Based on relevant, high-quality fluoroscopically guided epidural injections, with or without steroids, and results of previous systematic reviews, the evidence is Level I for caudal epidural injections, lumbar interlaminar epidural injections, lumbar transforaminal epidural injections, and cervical interlaminar epidural injections with strong recommendation for long-term effectiveness.The evidence for percutaneous adhesiolysis in managing disc herniation based on one high-quality, placebo-controlled RCT is Level II with moderate to strong recommendation for long-term improvement in patients nonresponsive to conservative management and fluoroscopically guided epidural injections. For thoracic disc herniation, based on one relevant, high-quality RCT of thoracic epidural with fluoroscopic guidance, with or without steroids, the evidence is Level II with moderate to strong recommendation for long-term effectiveness.Spinal stenosis: The evidence based on one high-quality RCT in each category the evidence is Level III to II for fluoroscopically guided caudal epidural injections with moderate to strong recommendation and Level II for fluoroscopically guided lumbar and cervical interlaminar epidural injections with moderate to strong recommendation for long-term effectiveness.The evidence for lumbar transforaminal epidural injections is Level IV to III with moderate recommendation with fluoroscopically guided lumbar transforaminal epidural injections for long-term improvement. The evidence for percutaneous adhesiolysis in lumbar stenosis based on relevant, moderate to high quality RCTs, observational studies, and systematic reviews is Level II with moderate to strong recommendation for long-term improvement after failure of conservative management and fluoroscopically guided epidural injections. Axial discogenic pain: The evidence for axial discogenic pain without facet joint pain or sacroiliac joint pain in the lumbar and cervical spine with fluoroscopically guided caudal, lumbar and cervical interlaminar epidural injections, based on one relevant high quality RCT in each category is Level II with moderate to strong recommendation for long-term improvement, with or without steroids. Post-surgery syndrome: The evidence for lumbar and cervical post-surgery syndrome based on one relevant, high-quality RCT with fluoroscopic guidance for caudal and cervical interlaminar epidural injections, with or without steroids, is Level II with moderate to strong recommendation for long-term improvement. For percutaneous adhesiolysis, based on multiple moderate to high-quality RCTs and systematic reviews, the evidence is Level I with strong recommendation for long-term improvement after failure of conservative management and fluoroscopically guided epidural injections. LIMITATIONS: The limitations of these guidelines include a continued paucity of high-quality studies for some techniques and various conditions including spinal stenosis, post-surgery syndrome, and discogenic pain. CONCLUSIONS: These epidural intervention guidelines including percutaneous adhesiolysis were prepared with a comprehensive review of the literature with methodologic quality assessment and determination of level of evidence with strength of recommendations.

ASIPP Guidelines for Sedation and Fasting Status of Patients Undergoing Interventional Pain Management Procedures.

Many of the patients undergoing interventional procedures have daily regimens of medications including analgesics, muscle relaxants, and other drugs that can have significant additive/synergistic effects during the perioperative period. Further, many patients also present with comorbid states, including obesity, cardiovascular, and pulmonary disease. Consequently, in the perioperative period, a significant number of patients have suffered permanent neurologic injury, hypoxic brain injury, and even death as a result of over sedation, hypoventilation, and spinal cord injury. In addition, physicians are concerned about aspiration, subsequent complications, and as a result, they ask patients to fast for several hours prior to the procedures. Based on extensive literature and consensus, a minimum fasting period is established as 2 hours before a procedure for clear liquids and 4 hours before procedure for light meals, rather than having all patients fast for 8 hours or even fasting beginning at midnight the night before the procedure. Gastrointestinal stimulants, gastric acid secretion blockers, and antacids may be used, even though not routinely recommended. Due to the nature of chronic pain and anxiety, many patients undergoing interventional techniques may require mild to moderate sedation. Deep sedation and/or general anesthesia for most interventional procedures is considered as unsafe, since the patient cannot communicate acute changes in symptoms, thus, resulting in morbidity and mortality, as well as creating compliance issues. We are adapting the published standards of the American Society of Anesthesiologists for monitoring patients under sedation, regardless of the location of the procedure, either office-based, in a surgery center, or a hospital outpatient department. These standards include monitoring of blood pressure, cardiac rhythm, temperature, pulse oximetry, and continuous quantitative end tidal CO2 monitoring. Sedation must be provided either by qualified anesthesia or non-anesthesia providers, with appropriate understanding of the medications, drug interactions, and resuscitative protocols.KEY WORDS: Guidelines, sedation, fasting status, monitoring, neurological complications.

Responsible, Safe, and Effective Use of Antithrombotics and Anticoagulants in Patients Undergoing Interventional Techniques: American Society of Interventional Pain Physicians (ASIPP) Guidelines.

BACKGROUND: Interventional pain management involves diagnosis and treatment of chronic pain. This specialty utilizes minimally invasive procedures to target therapeutics to the central nervous system and the spinal column. A subset of patients encountered in interventional pain are medicated using anticoagulant or antithrombotic drugs to mitigate thrombosis risk. Since these drugs target the clotting system, bleeding risk is a consideration accompanying interventional procedures. Importantly, discontinuation of anticoagulant or antithrombotic drugs exposes underlying thrombosis risk, which can lead to significant morbidity and mortality especially in those with coronary artery or cerebrovascular disease. This review summarizes the literature and provides guidelines based on best evidence for patients receiving anti-clotting therapy during interventional pain procedures. STUDY DESIGN: Best evidence synthesis. OBJECTIVE: To provide a current and concise appraisal of the literature regarding an assessment of the bleeding risk during interventional techniques for patients taking anticoagulant and/or antithrombotic medications. METHODS: A review of the available literature published on bleeding risk during interventional pain procedures, practice patterns and perioperative management of anticoagulant and antithrombotic therapy was conducted. Data sources included relevant literature identified through searches of EMBASE and PubMed from 1966 through August 2018 and manual searches of the bibliographies of known primary and review articles. RESULTS: 1. There is good evidence for risk stratification by categorizing multiple interventional techniques into low-risk, moderate-risk, and high-risk. Also, their risk should be upgraded based on other risk factors.2. There is good evidence for the risk of thromboembolic events in patients who interrupt antithrombotic therapy. 3. There is good evidence supporting discontinuation of low dose aspirin for high risk and moderate risk procedures for at least 3 days, and there is moderate evidence that these may be continued for low risk or some intermediate risk procedures.4. There is good evidence that discontinuation of anticoagulant therapy with warfarin, heparin, dabigatran (Pradaxa®), argatroban (Acova®), bivalirudin (Angiomax®), lepirudin (Refludan®), desirudin (Iprivask®), hirudin, apixaban (Eliquis®), rivaroxaban (Xarelto®), edoxaban (Savaysa®, Lixiana®), Betrixaban(Bevyxxa®), fondaparinux (Arixtra®) prior to interventional techniques with individual consideration of pharmacokinetics and pharmacodynamics of the drugs and individual risk factors increases safety.5. There is good evidence that diagnosis of epidural hematoma is based on severe pain at the site of the injection, rapid neurological deterioration, and MRI with surgical decompression with progressive neurological dysfunction to avoid neurological sequelae.6. There is good evidence that if thromboembolic risk is high, low molecular weight heparin bridge therapy can be instituted during cessation of the anticoagulant, and the low molecular weight heparin can be discontinued 24 hours before the pain procedure.7. There is fair evidence that the risk of thromboembolic events is higher than that of epidural hematoma formation with the interruption of antiplatelet therapy preceding interventional techniques, though both risks are significant.8. There is fair evidence that multiple variables including anatomic pathology with spinal stenosis and ankylosing spondylitis; high risk procedures and moderate risk procedures combined with anatomic risk factors; bleeding observed during the procedure, and multiple attempts during the procedures increase the risk for bleeding complications and epidural hematoma.9. There is fair evidence that discontinuation of phosphodiesterase inhibitors is optional (dipyridamole [Persantine], cilostazol [Pletal]. However, there is also fair evidence to discontinue Aggrenox [dipyridamole plus aspirin]) 3 days prior to undergoing interventional techniques of moderate and high risk. 10. There is fair evidence to make shared decision making between the patient and the treating physicians with the treating physician and to consider all the appropriate risks associated with continuation or discontinuation of antithrombotic or anticoagulant therapy.11. There is fair evidence that if thromboembolic risk is high antithrombotic therapy may be resumed 12 hours after the interventional procedure is performed.12. There is limited evidence that discontinuation of antiplatelet therapy (clopidogrel [Plavix®], ticlopidine [Ticlid®], Ticagrelor [Brilinta®] and prasugrel [Effient®]) avoids complications of significant bleeding and epidural hematomas.13. There is very limited evidence supporting the continuation or discontinuation of most NSAIDs, excluding aspirin, for 1 to 2 days and some 4 to 10 days, since these are utilized for pain management without cardiac or cerebral protective effect. LIMITATIONS: The continued paucity of the literature with discordant recommendations. CONCLUSION: Based on the survey of current literature, and published clinical guidelines, recommendations for patients presenting with ongoing antithrombotic therapy prior to interventional techniques are variable, and are based on comprehensive analysis of each patient and the risk-benefit analysis of intervention. KEY WORDS: Perioperative bleeding, bleeding risk, practice patterns, anticoagulant therapy, antithrombotic therapy, interventional techniques, safety precautions, pain.

A Brief History of the Opioid Epidemic and Strategies for Pain Medicine.

The opioid epidemic has resulted from myriad causes and will not be solved by any simple solution. Consequent to a staggering increase in opioid-related deaths in the USA, various governmental inputs and stakeholder strategies have been proposed and implemented with varying success. This article summarizes the history of opioid use and explores the causes for the present day epidemic. Recent trends in opioid-related data demonstrate an almost fourfold increase in overdose deaths from 1999 to 2008. Tragically, opioids claimed over 64,000 lives just last year. Some solutions have undergone legislation, including the limitation of numbers of opioids postsurgery, as well as growing national prevalence of enhanced recovery after surgery protocols which focus on reduced postoperative opioid consumption and shortened hospital stays. Stricter prescribing practices and prescription monitoring programs have been instituted in the recent past. Improvement in abuse deterrent strategies which is a major focus of the Food and Drug Administration (FDA) for all opioid preparations will likely play an important role by increasing the safety of these medications. Future potential strategies such as additional legislative policies, public awareness, and physician education are also detailed in this review.

Effectiveness of Thermal Annular Procedures in Treating Discogenic Low Back Pain.

BACKGROUND: Discogenic low back is a distinct clinic entity characterized by pain arising from a damaged disc. The diagnosis is clouded by the controversy surrounding discography. The treatment options are limited, with unsatisfactory results from both conservative treatment and surgery. Multiple interventional therapies have been developed to treat discogenic pain, but most have not yet been validated by high quality studies.The best studied treatment for discogenic pain is the use of heat, which has been labeled as thermal intradiscal procedures (TIPs) by the Centers for Medicare and Medicaid Services (CMS). As the pathology is located in the annulus, we use the term thermal annular procedures (TAPs). OBJECTIVES: The aim of this study is to evaluate and update the efficacy of TAPs to treat chronic refractory discogenic pain. STUDY DESIGN: The design of this study is a systematic review. METHODS: The available literature on TAPs in treating chronic refractory discogenic pain was reviewed. The quality of each article used in this analysis was assessed.The level of evidence was classified on a 5-point scale from strong, based upon multiple randomized controlled trials (RCTs) to weak, based upon consensus, as developed by the US Preventive Services Task Force (USPSTF) and modified by the American Society of Interventional Pain Physicians (ASIPP).Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to September 2015 and manual searches of the bibliographies of known primary and review articles.The primary outcome measures were pain relief and functional improvement of at least 40%. Short-term efficacy was defined as improvement for less than 6 months; long-term efficacy was defined as improvement for 6 months or more. RESULTS: For this systematic review, 49 studies were identified. Of these, there were 4 RCTs and no observational studies which met the inclusion criteria. Based upon 2 RCTs showing efficacy, with no negative trials, there is Level I, or strong, evidence of the efficacy of biacuplasty in the treatment of chronic, refractory discogenic pain.Based upon one high-quality RCT showing efficacy and one moderate-quality RCT interpreted as showing no benefit, there is Level III, or moderate, evidence supporting the use of intradiscal electrothermal therapy (IDET) in treating chronic, refractory discogenic pain.The evidence supporting the use of discTRODE is level V, or limited. CONCLUSION: The evidence is Level I, or strong, that percutaneous biacuplasty is efficacious in the treatment of chronic, refractory discogenic pain. Biacuplasty may be considered as a first-line treatment for chronic, refractory discogenic pain.The evidence is Level III, or moderate, that IDET is efficacious in the treatment of chronic, refractory discogenic pain.The evidence is Level V, or limited, that discTRODE is efficacious in the treatment of chronic, refractory discogenic pain.Key words: Spinal pain, chronic low back pain, intradiscal disorder, IDET, biacuplasty, discTRODE, thermal intradiscal disorders, thermal annular disorders.

Responsible, Safe, and Effective Prescription of Opioids for Chronic Non-Cancer Pain: American Society of Interventional Pain Physicians (ASIPP) Guidelines.

BACKGROUND: Opioid use, abuse, and adverse consequences, including death, have escalated at an alarming rate since the 1990s. In an attempt to control opioid abuse, numerous regulations and guidelines for responsible opioid prescribing have been developed by various organizations. However, the US opioid epidemic is continuing and drug dose deaths tripled during 1999 to 2015. Recent data show a continuing increase in deaths due to natural and semisynthetic opioids, a decline in methadone deaths, and an explosive increase in the rates of deaths involving other opioids, specifically heroin and illicit synthetic fentanyl. Contrary to scientific evidence of efficacy and negative recommendations, a significant proportion of physicians and patients (92%) believe that opioids reduce pain and a smaller proportion (57%) report better quality of life. In preparation of the current guidelines, we have focused on the means to reduce the abuse and diversion of opioids without jeopardizing access for those patients suffering from non-cancer pain who have an appropriate medical indication for opioid use. OBJECTIVES: To provide guidance for the prescription of opioids for the management of chronic non-cancer pain, to develop a consistent philosophy among the many diverse groups with an interest in opioid use as to how appropriately prescribe opioids, to improve the treatment of chronic non-cancer pain and to reduce the likelihood of drug abuse and diversion. These guidelines are intended to provide a systematic and standardized approach to this complex and difficult arena of practice, while recognizing that every clinical situation is unique. METHODS: The methodology utilized included the development of objectives and key questions. The methodology also utilized trustworthy standards, appropriate disclosures of conflicts of interest, as well as a panel of experts from various specialties and groups. The literature pertaining to opioid use, abuse, effectiveness, and adverse consequences was reviewed, with a best evidence synthesis of the available literature, and utilized grading for recommendation as described by the Agency for Healthcare Research and Quality (AHRQ).Summary of Recommendations:i. Initial Steps of Opioid Therapy 1. Comprehensive assessment and documentation. (Evidence: Level I; Strength of Recommendation: Strong) 2. Screening for opioid abuse to identify opioid abusers. (Evidence: Level II-III; Strength of Recommendation: Moderate) 3. Utilization of prescription drug monitoring programs (PDMPs). (Evidence: Level I-II; Strength of Recommendation: Moderate to strong) 4. Utilization of urine drug testing (UDT). (Evidence: Level II; Strength of Recommendation: Moderate) 5. Establish appropriate physical diagnosis and psychological diagnosis if available. (Evidence: Level I; Strength of Recommendation: Strong) 6. Consider appropriate imaging, physical diagnosis, and psychological status to collaborate with subjective complaints. (Evidence: Level III; Strength of Recommendation: Moderate) 7. Establish medical necessity based on average moderate to severe (≥ 4 on a scale of 0 - 10) pain and/or disability. (Evidence: Level II; Strength of Recommendation: Moderate) 8. Stratify patients based on risk. (Evidence: Level I-II; Strength of Recommendation: Moderate) 9. Establish treatment goals of opioid therapy with regard to pain relief and improvement in function. (Evidence: Level I-II; Strength of Recommendation: Moderate) 10. Obtain a robust opioid agreement, which is followed by all parties. (Evidence: Level III; Strength of Recommendation: Moderate)ii. Assessment of Effectiveness of Long-Term Opioid Therapy 11. Initiate opioid therapy with low dose, short-acting drugs, with appropriate monitoring. (Evidence: Level II; Strength of Recommendation: Moderate) 12. Consider up to 40 morphine milligram equivalent (MME) as low dose, 41 to 90 MME as a moderate dose, and greater than 91 MME as high dose. (Evidence: Level II; Strength of Recommendation: Moderate) 13. Avoid long-acting opioids for the initiation of opioid therapy. (Evidence: Level I; Strength of Recommendation: Strong) 14. Recommend methadone only for use after failure of other opioid therapy and only by clinicians with specific training in its risks and uses, within FDA recommended doses. (Evidence: Level I; Strength of Recommendation: Strong) 15. Understand and educate the patients of the effectiveness and adverse consequences. (Evidence: Level I; Strength of Recommendation: Strong) 16. Similar effectiveness for long-acting and short-acting opioids with increased adverse consequences of long-acting opioids. (Evidence: Level I-II; Strength of recommendation: Moderate to strong) 17. Periodically assess pain relief and/or functional status improvement of ≥ 30% without adverse consequences. (Evidence: Level II; Strength of recommendation: Moderate) 18. Recommend long-acting or high dose opioids only in specific circumstances with severe intractable pain. (Evidence: Level I; Strength of Recommendation: Strong)iii. Monitoring for Adherence and Side Effects 19. Monitor for adherence, abuse, and noncompliance by UDT and PDMPs. (Evidence: Level I-II; Strength of Recommendation: Moderate to strong) 20. Monitor patients on methadone with an electrocardiogram periodically. (Evidence: Level I; Strength of Recommendation: Strong). 21. Monitor for side effects including constipation and manage them appropriately, including discontinuation of opioids when indicated. (Evidence: Level I; Strength of Recommendation: Strong)iv. Final Phase 22. May continue with monitoring with continued medical necessity, with appropriate outcomes. (Evidence: Level I-II; Strength of Recommendation: Moderate) 23. Discontinue opioid therapy for lack of response, adverse consequences, and abuse with rehabilitation. (Evidence: Level III; Strength of Recommendation: Moderate) CONCLUSIONS: These guidelines were developed based on comprehensive review of the literature, consensus among the panelists, in consonance with patient preferences, shared decision-making, and practice patterns with limited evidence, based on randomized controlled trials (RCTs) to improve pain and function in chronic non-cancer pain on a long-term basis. Consequently, chronic opioid therapy should be provided only to patients with proven medical necessity and stability with improvement in pain and function, independently or in conjunction with other modalities of treatments in low doses with appropriate adherence monitoring and understanding of adverse events.Key words: Chronic pain, persistent pain, non-cancer pain, controlled substances, substance abuse, prescription drug abuse, dependency, opioids, prescription monitoring, drug testing, adherence monitoring, diversionDisclaimer: The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."

A Best-Evidence Systematic Appraisal of the Diagnostic Accuracy and Utility of Facet (Zygapophysial) Joint Injections in Chronic Spinal Pain.

BACKGROUND: Spinal zygapophysial, or facet, joints are a source of axial spinal pain and referred pain in the extremities. Conventional clinical features and other noninvasive diagnostic modalities are unreliable in diagnosing zygapophysial joint pain. STUDY DESIGN: A systematic review of the diagnostic accuracy of spinal facet joint nerve blocks. OBJECTIVE: To determine the diagnostic accuracy of spinal facet joint nerve blocks in chronic spinal pain. METHODS: A methodological quality assessment of included studies was performed using Quality Appraisal of Reliability Studies (QAREL). Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were utilized for analysis. The level of evidence was classified as Level I to V based on the grading of evidence utilizing best evidence synthesis. Data sources included relevant literature identified through searches of PubMed and other electronic searches published from 1966 through March 2015, Cochrane reviews, and manual searches of the bibliographies of known primary and review articles. OUTCOME MEASURES: Studies must have been performed utilizing controlled local anesthetic blocks. The criterion standard must have been at least 50% pain relief from baseline scores and the ability to perform previously painful movements. RESULTS: The available evidence is Level I for lumbar facet joint nerve blocks with the inclusion of a total of 17 studies with dual diagnostic blocks, with at least 75% pain relief with an average prevalence of 16% to 41% and false-positive rates of 25% to 44%. The evidence for diagnosis of cervical facet joint pain with cervical facet joint nerve blocks is Level II based on a total of 11 controlled diagnostic accuracy studies, with significant variability among the prevalence in a heterogenous population with internal inconsistency. The prevalence rates ranged from 36% to 67% with at least 80% pain relief as the criterion standard and a false-positive rate of 27% to 63%. The level of evidence for the diagnostic accuracy of thoracic facet joint nerve blocks is Level II with 80% or higher pain relief as the criterion standard with a prevalence ranging from 34% to 48% and false-positive rates ranging from 42% to 48%. LIMITATIONS: The shortcomings of this systematic review include a paucity of literature related to the thoracic spine, continued debate on an appropriate gold standard, appropriateness of diagnostic blocks, and utility. CONCLUSION: The evidence is Level I for the diagnostic accuracy of lumbar facet joint nerve blocks, Level II for cervical facet joint nerve blocks, and Level II for thoracic facet joint nerve blocks in assessment of chronic spinal pain.

Detailed analysis of allergic cutaneous reactions to spinal cord stimulator devices.

The use of spinal cord stimulation (SCS) devices to treat chronic, refractory neuropathic pain continues to expand in application. While device-related complications have been well described, inflammatory reactions to the components of these devices remain underreported. In contrast, hypersensitivity reactions associated with other implanted therapies, such as endovascular and cardiac rhythm devices, have been detailed. The purpose of this case series is to describe the clinical presentation and course of inflammatory reactions as well as the histology of these reactions. All patients required removal of the entire device after developing inflammatory reactions over a time course of 1-3 months. Two patients developed a foreign body reaction in the lead insertion wound as well as at the implantable pulse generator site, with histology positive for giant cells. One patient developed an inflammatory dermatitis on the flank and abdomen that resolved with topical hydrocortisone. "In vivo" testing with a lead extension fragment placed in the buttock resulted in a negative reaction followed by successful reimplantation of an SCS device. Inflammatory reactions to SCS devices can manifest as contact dermatitis, granuloma formation, or foreign body reactions with giant cell formation. Tissue diagnosis is essential, and is helpful to differentiate an inflammatory reaction from infection. The role of skin patch testing for 96 hours may not be suited to detect inflammatory giant cell reactions that manifest several weeks post implantation.

Magnetic resonance imaging of the lumbar spine in a patient with a spinal cord stimulator.

BACKGROUND: The use of magnetic resonance imaging (MRI) is continuously escalating for the evaluation of patients with persistent pain following lumbar spine surgery (LSS). Spinal cord stimulation (SCS) therapy is being clinically applied much more commonly for the management of chronic pain following LSS. There is an increased probability that these 2 incompatible modalities may be accidentally used in the same patient. OBJECTIVES: The purpose of this case report is to: (1) summarize a case in which a patient with a thoracic spinal cord stimulator underwent a diagnostic lumbar MRI, (2) describe the 3 magnetic fields used to generate images and their interactions with SCS devices, and (3) summarize the present literature. STUDY DESIGN: Case report. SETTING: University hospital. RESULTS: Aside from mild heat sensations in the generator/pocket site and very low intensity shocking sensations in the back while in the MRI scanner, the patient emerged from the study with no clinically detected adverse events. Subsequent activation of the SCS device would result in a brief intense shocking sensation. This persisted whenever the device was activated and required Implantable Pulse Generator (IPG) replacement. Electrical analysis revealed that some of the output circuitry switches, which regulate IPG stimulation and capacitor charge balancing, were damaged, most likely by MRI radiofrequency injected current. LIMITATIONS: Single case of a patient with a thoracic SCS having a lumbar MRI study. CONCLUSION: This case demonstrates the lack of compatibility of lumbar MRI and the Precision SCS system as well as one of the possible patient adverse events that can occur when patients are exposed to MRI outside of the approved device labeling.

An update of comprehensive evidence-based guidelines for interventional techniques in chronic spinal pain. Part II: guidance and recommendations.

OBJECTIVE: To develop evidence-based clinical practice guidelines for interventional techniques in the diagnosis and treatment of chronic spinal pain. METHODOLOGY: Systematic assessment of the literature. EVIDENCE: I. Lumbar Spine • The evidence for accuracy of diagnostic selective nerve root blocks is limited; whereas for lumbar provocation discography, it is fair. • The evidence for diagnostic lumbar facet joint nerve blocks and diagnostic sacroiliac intraarticular injections is good with 75% to 100% pain relief as criterion standard with controlled local anesthetic or placebo blocks. • The evidence is good in managing disc herniation or radiculitis for caudal, interlaminar, and transforaminal epidural injections; fair for axial or discogenic pain without disc herniation, radiculitis or facet joint pain with caudal, and interlaminar epidural injections, and limited for transforaminal epidural injections; fair for spinal stenosis with caudal, interlaminar, and transforaminal epidural injections; and fair for post surgery syndrome with caudal epidural injections and limited with transforaminal epidural injections. • The evidence for therapeutic facet joint interventions is good for conventional radiofrequency, limited for pulsed radiofrequency, fair to good for lumbar facet joint nerve blocks, and limited for intraarticular injections. • For sacroiliac joint interventions, the evidence for cooled radiofrequency neurotomy is fair; limited for intraarticular injections and periarticular injections; and limited for both pulsed radiofrequency and conventional radiofrequency neurotomy. • For lumbar percutaneous adhesiolysis, the evidence is fair in managing chronic low back and lower extremity pain secondary to post surgery syndrome and spinal stenosis. • For intradiscal procedures, the evidence for intradiscal electrothermal therapy (IDET) and biaculoplasty is limited to fair and is limited for discTRODE. • For percutaneous disc decompression, the evidence is limited for automated percutaneous lumbar discectomy (APLD), percutaneous lumbar laser disc decompression, and Dekompressor; and limited to fair for nucleoplasty for which the Centers for Medicare and Medicaid Services (CMS) has issued a noncoverage decision. II. Cervical Spine • The evidence for cervical provocation discography is limited; whereas the evidence for diagnostic cervical facet joint nerve blocks is good with a criterion standard of 75% or greater relief with controlled diagnostic blocks. • The evidence is good for cervical interlaminar epidural injections for cervical disc herniation or radiculitis; fair for axial or discogenic pain, spinal stenosis, and post cervical surgery syndrome. • The evidence for therapeutic cervical facet joint interventions is fair for conventional cervical radiofrequency neurotomy and cervical medial branch blocks, and limited for cervical intraarticular injections. III. Thoracic Spine • The evidence is limited for thoracic provocation discography and is good for diagnostic accuracy of thoracic facet joint nerve blocks with a criterion standard of at least 75% pain relief with controlled diagnostic blocks. • The evidence is fair for thoracic epidural injections in managing thoracic pain. • The evidence for therapeutic thoracic facet joint nerve blocks is fair, limited for radiofrequency neurotomy, and not available for thoracic intraarticular injections. IV. Implantables • The evidence is fair for spinal cord stimulation (SCS) in managing patients with failed back surgery syndrome (FBSS) and limited for implantable intrathecal drug administration systems. V. ANTICOAGULATION • There is good evidence for risk of thromboembolic phenomenon in patients with antithrombotic therapy if discontinued, spontaneous epidural hematomas with or without traumatic injury in patients with or without anticoagulant therapy to discontinue or normalize INR with warfarin therapy, and the lack of necessity of discontinuation of nonsteroidal anti-inflammatory drugs (NSAIDs), including low dose aspirin prior to performing interventional techniques. • There is fair evidence with excessive bleeding, including epidural hematoma formation with interventional techniques when antithrombotic therapy is continued, the risk of higher thromboembolic phenomenon than epidural hematomas with discontinuation of antiplatelet therapy prior to interventional techniques and to continue phosphodiesterase inhibitors (dipyridamole, cilostazol, and Aggrenox). • There is limited evidence to discontinue antiplatelet therapy with platelet aggregation inhibitors to avoid bleeding and epidural hematomas and/or to continue antiplatelet therapy (clopidogrel, ticlopidine, prasugrel) during interventional techniques to avoid cerebrovascular and cardiovascular thromboembolic fatalities. • There is limited evidence in reference to newer antithrombotic agents dabigatran (Pradaxa) and rivaroxan (Xarelto) to discontinue to avoid bleeding and epidural hematomas and are continued during interventional techniques to avoid cerebrovascular and cardiovascular thromboembolic events. CONCLUSIONS: Evidence is fair to good for 62% of diagnostic and 52% of therapeutic interventions assessed. DISCLAIMER: The authors are solely responsible for the content of this article. No statement on this article should be construed as an official position of ASIPP. The guidelines do not represent "standard of care."

Ultrasonographic guidance and characterization of cryoanalgesic lesions in treating a case of refractory sural neuroma.

The recurrent pain of a neuroma following surgical excision and burial of nerve endings can be clinically challenging to manage. Cryoanalgesia in conjunction with ultrasound guidance was used successfully to manage this type of pain. Furthermore, ultrasound provided visualization of the cryolesions, as well as the relationships of the ice ball to the surrounding tissue. Following the completion of the freeze cycle, the tissue can be monitored for return to its usual morphology during the thaw period.

Plasma disc decompression compared with fluoroscopy-guided transforaminal epidural steroid injections for symptomatic contained lumbar disc herniation: a prospective, randomized, controlled trial.

OBJECT: Patients with radiculopathy, with or without back pain, often do not respond to conservative care and may be considered for epidural steroid injection therapy or a disc decompression procedure. Plasma disc decompression (PDD) using the Coblation SpineWand device is a percutaneous, minimally invasive interventional procedure. The purpose of this study was to evaluate clinical outcomes with PDD as compared with standard care using fluoroscopy-guided transforaminal epidural steroid injection (TFESI) over the course of 2 years. METHODS: This was a multicenter randomized controlled clinical study. Ninety patients (18-66 years old) who had sciatica (visual analog scale score > or = 50) associated with a single-level lumbar contained disc herniation were enrolled. In all cases, their condition was refractory to initial conservative care and 1 epidural steroid injection had failed. Participants were randomly assigned to receive either PDD (46 patients) or TFESI (44 patients, up to 2 injections). RESULTS: The patients in the PDD Group had significantly greater reduction in leg pain scores and significantly improved Oswestry Disability Index and 36-Item Short Form Health Survey ([SF-36], physical function, bodily pain, social function, and physical components summary) scores than those in the TFESI Group. During the 2-year follow-up, 25 (56%) of the patients in the PDD Group and 11 (28%) of those in the TFESI Group remained free from having a secondary procedure following the study procedure (log-rank p = 0.02). A significantly higher percentage of patients in the PDD Group showed minimum clinically important change in scores for leg and back pain and SF-36 scores that exceeded literature-based minimum clinically important changes. Procedure-related adverse events, including injection site pain, increased leg or back pain, weakness, and lightheadedness, were observed in 5 patients in the PDD Group (7 events) and 7 in the TFESI Group (14 events). CONCLUSIONS: In study patients who had radicular pain associated with a contained lumbar disc herniation, those patients treated with PDD had significantly reduced pain and better quality of life scores than those treated using repeated TFESI. In addition, significantly more PDD patients than TFESI patients avoided having to undergo a secondary procedure during the 2-year study follow-up.

Low and therapeutic doses of antidepressants are associated with similar response in the context of multimodal treatment of pain.

BACKGROUND: Antidepressants are prescribed in a wide range of doses to treat both depression and chronic pain, with optimal psychopharmacology individualized for each patient. In the past decade more antidepressants from different chemical classes have become available and are being used for the treatment of both chronic pain and depression. OBJECTIVE: To review the utilization pattern changes and compare response rates of different classes and doses of antidepressants for various pain conditions in the context of multimodal therapies. DESIGN: Chart review. METHODS: We reviewed 5,916 records at an outpatient multidisciplinary pain center. Of these, 379 records were for patients diagnosed with cancer pain. Because the mechanisms and treatment approaches to cancer pain can differ greatly from non-cancer chronic pain, these records were excluded from the analysis. We assessed 1,506 medical records for patients with chronic non-caner pain who had used at least one antidepressant, with the main outcome measure being the Numeric Rating Pain Scale, 0-10. RESULTS: Of the 5,916 charts reviewed, 1,506 (25.4%) chronic non-cancer pain charts recorded the prescription of at least one antidepressant. Most patients received a combination of medications and procedures. Of the 450 patients receiving secondary amines, favorable responses were recorded for 340 (76%) patients, while 103 (23%) did not respond and 7 had unknown responses. Of the 492 patients receiving tertiary amines, favorable responses were recorded for 375 (76%) patients, while 113 (23%) did not respond, and 4 had unknown responses. Of the 533 patients receiving SSRI/SNRIs, favorable responses were recorded for 382 (72%) patients, while 147 (28%) did not respond, and 4 had unknown responses. Of the 369 patients receiving atypical antidepressants, favorable responses were recorded for 272 (74%) patients, while 94 (25%) did not respond, and 3 had unknown responses. LIMITATIONS: A retrospective study design and the use of antidepressants as a part of multimodal treatment of pain. CONCLUSION: The data suggest that in the context of multimodal treatment for chronic pain, antidepressant therapy at both low and therapeutic doses demonstrates similar response rates. Tricyclic antidepressants (TCAs), which include secondary and tertiary amines, as well as SSRI/SNRIs and atypicals, all appear to show similar favorable response rates.

Fundamentals of interventional pain medicine.

Chronic pain is one of the most common and challenging medical problems facing our society. The specialty of pain medicine has grown steadily in recent years, largely because of the recognition that multiple factors contribute to chronic pain. The practice of pain medicine is multidisciplinary in approach, incorporating modalities from various specialties to ensure the comprehensive evaluation and treatment of the pain patient. The integration of various specialties such as anesthesiology, neurology, neurologic surgery, orthopedic surgery, physical medicine, and psychiatry is essential to treating patients with chronic pain and to establishing continuity of care. Research in the last 30 years has developed a variety of alternatives or adjuncts to opiates for chronic pain, including neuroactive medications, counterstimulation methods, and cognitive-behavioral therapies. Pain medicine specialists have provided leadership in the development of the practice, with the application of a wide verity of central and peripheral nerve blocks, sympathetic and neurolytic blocks, intradiscal procedures, neuromodulation techniques, intrathecal infusion systems, and other technical procedures that are firmly linked to a biomedical model of pain.

Epidural clonidine relieves intractable neuropathic itch associated with herpes zoster-related pain.

OBJECTIVE: We present a case of intense herpes zoster-related pain and itching in the ophthalmic division of the trigeminal nerve (V1). Successful pain and itch management was achieved after insertion of a high thoracic epidural catheter with a continuous infusion of bupivacaine and clonidine. CASE REPORT: A 73-year-old woman with metastatic malignant melanoma developed acute herpes zoster-related pain and itching unresponsive to conventional oral medications. The patient described severe and frequent attacks of lancinating pain occurring in the dermatomal distribution of the left ophthalmic division of the trigeminal nerve. She also had a disturbing itch in the same distribution as her pain. The patient had significant reduction in the frequency and intensity of the lancinating attacks after placement of a thoracic epidural catheter with continuous infusion of 1 microg/mL clonidine and 0.05% bupivacaine. The itching resolved completely as well. CONCLUSION: High thoracic epidural infusion of bupivacaine and clonidine was beneficial in relieving neuropathic itch in a patient with acute herpes zoster-related pain in the distribution of the trigeminal nerve.

Use of meperidine in patient-controlled analgesia and the development of a normeperidine toxic reaction.

HYPOTHESIS: Intravenous patient-controlled analgesia (IV PCA) meperidine hydrochloride can be used with a reasonable margin of safety. DESIGN: A retrospective review was performed of 355 medical records of patients receiving IV PCA meperidine treatment. Four groups of patients were defined, based on daily meperidine dose and the presence or absence of central nervous system excitation adverse effects. Use of more than 600 mg/d of meperidine hydrochloride was considered a high dose. SETTING: University tertiary care hospital. PARTICIPANTS: Postoperative patients from general, orthopedic, neurosurgical, gynecological, and urologic procedures receiving IV PCA. INTERVENTIONS: If patients were judged to have consumed significant amounts of meperidine, the analgesic regimen was modified to (1) discontinue meperidine therapy, (2) substitute hydromorphone hydrochloride, or (3) decrease the use of meperidine by adding oral methadone hydrochloride or transdermal fentanyl citrate to the regimen. MAIN OUTCOME MEASURES: Patients who received less than 10 mg/kg per day of IV PCA meperidine hydrochloride therapy were unlikely to experience central nervous system excitatory adverse effects and maintain adequate analgesia. RESULTS: The mean meperidine hydrochloride consumption for those patients classified as high dose, asymptomatic was 13.3 mg/kg per day (95% confidence interval, 12.1-14.4 mg/kg per day). This differed statistically significantly (P<.05) from the mean meperidine hydrochloride dose in patients classified as high dose, symptomatic, which was 16.9 mg/kg per day (95% confidence interval, 14.7-19.2 mg/kg per day). The duration of meperidine use did not differ among the 4 patient groups. The incidence of a central nervous system toxic reaction associated with IV PCA meperidine therapy was 2%. CONCLUSIONS: We recommend 10 mg/kg per day as a maximum safe meperidine hydrochloride dose by an IV PCA device for no longer than 3 days. Daily patient evaluation is mandatory. Care must also be taken when using this dose to ensure the absence of renal dysfunction or enhanced hepatic metabolism of meperidine.