A Systematic Literature Review of Spine Neurostimulation Therapies for the Treatment of Pain.

OBJECTIVE: To conduct a systematic literature review of spinal cord stimulation (SCS) for pain. DESIGN: Grade the evidence for SCS. METHODS: An 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. RESULTS: SCS 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). CONCLUSIONS: High-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.

Outcomes of Sympathetic Blocks in the Management of Complex Regional Pain Syndrome: A Retrospective Cohort Study.

BACKGROUND: Sympathetic dysfunction may be present in complex regional pain syndrome, and sympathetic blocks are routinely performed in practice. To investigate the therapeutic and predictive values of sympathetic blocks, the authors test the hypotheses that sympathetic blocks provide analgesic effects that may be associated with the temperature differences between the two extremities before and after the blocks and that the effects of sympathetic blocks may predict the success (defined as achieving more than 50% pain reduction) of spinal cord stimulation trials. METHODS: The authors performed a retrospective study of 318 patients who underwent sympathetic blocks in a major academic center (2009 to 2016) to assess the association between pain reduction and preprocedure temperature difference between the involved and contralateral limbs. The primary outcome was pain improvement by more than 50%, and the secondary outcome was duration of more than 50% pain reduction per patient report. The authors assessed the association between pain reduction and the success rate of spinal cord stimulation trials. RESULTS: Among the 318 patients, 255 were diagnosed with complex regional pain syndrome and others with various sympathetically related disorders. Successful pain reduction (more than 50%) was observed in 155 patients with complex regional pain syndrome (155 of 255, 61%). The majority of patients (132 of 155, 85%) experienced more than 50% pain relief for 1 to 4 weeks or longer. The degree and duration of pain relief were not associated with preprocedure temperature parameters with estimated odds ratio of 1.03 (97.5% CI, 0.95-1.11) or 1.01 (97.5% CI, 0.96-1.06) for one degree decrease (P = 0.459 or 0.809). There was no difference in the success rate of spinal cord stimulation trials between patients with or without more than 50% pain relief after sympathetic blocks (35 of 40, 88% vs. 26 of 29, 90%, P > 0.990). CONCLUSIONS: The authors conclude that sympathetic blocks may be therapeutic in patients with complex regional pain syndrome regardless of preprocedure limb temperatures. The effects of sympathetic blocks do not predict the success of spinal cord stimulation.

The MIST Guidelines: The Lumbar Spinal Stenosis Consensus Group Guidelines for Minimally Invasive Spine Treatment.

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.

The road to accreditation for fellowship training in regional anesthesiology and acute pain medicine.

PURPOSE OF REVIEW: The purpose of this review is to provide the background and rationale for pursuing accreditation of regional anesthesiology and acute pain medicine (RAAPM) fellowships, explain specific steps and challenges in the process, and forecast the future of fellowship training. RECENT FINDINGS: In 2016, the first fellowship program in RAAPM was able to apply for accreditation from the Accreditation Council for Graduate Medical Education (ACGME). The establishment of this newly accredited subspecialty fellowship and the announcement of the first accredited programs represented a tremendous achievement in anesthesiology training and medical education in general and was the culmination of nearly 4 years of dedicated effort. SUMMARY: Programs with initial ACGME accreditation are on a 2-year term and will be reviewed to evaluate adherence to the program requirements and the quality of fellowship training. Deficiencies identified will need to be resolved or face loss of accreditation. However, a program's maintenance of accreditation represents a commitment to its fellows to provide a training experience that can be held as a benchmark for all programs.

Scope and Nature of Pain- and Analgesia-Related Content of the United States Medical Licensing Examination (USMLE).

Background: "The ongoing opioid crisis lies at the intersection of two substantial public health challenges-reducing the burden of suffering from pain and containing the rising toll of the harms that can result from the use of opioid medications" [1]. Improved pain education for health care providers is an essential component of the multidimensional response to both still-unmet challenges [2,3]. Despite the importance of licensing examinations in assuring competency in health care providers, there has been no prior appraisal of pain and related content within the United States Medical Licensing Examination (USMLE). Methods: An expert panel developed a novel methodology for characterizing USMLE questions based on pain core competencies and topical and public health relevance. Results: Under secure conditions, raters used this methodology to score 1,506 questions, with 28.7% (432) identified as including the word "pain." Of these, 232 questions (15.4% of the 1,506 USMLE questions reviewed) were assessed as being fully or partially related to pain, rather than just mentioning pain but not testing knowledge of its mechanisms and their implications for treatment. The large majority of questions related to pain (88%) focused on assessment rather than safe and effective pain management, or the context of pain. Conclusions: This emphasis on assessment misses other important aspects of safe and effective pain management, including those specific to opioid safety. Our findings inform ways to improve the long-term education of our medical and other graduates, thereby improving the health care of the populations they serve.

Regional Anesthesia and Pain Medicine: US Anesthesiology Resident Training-The Year 2015.

BACKGROUND AND OBJECTIVES: The Anesthesiology Review Committee of the Accreditation Council for Graduate Medical Education sets core requirements for residency program accreditation. We periodically report and analyze the US anesthesiology residents' training experience in regional anesthesia and pain medicine. METHODS: Resident caseload, procedure, and pain medicine evaluation data were aggregated for the resident cohort who graduated in 2015. These data were analyzed for present-day experience and compared with previous reports from years 1980, 1990, and 2000 graduates. RESULTS: Data were available for 1631 residents who graduated from 129 training programs. Regional anesthesia as a portion of the overall anesthesiology residents' training experience remains unchanged since 1990. The distribution of regional anesthesia training has shifted from neuraxial to peripheral blocks. All residents at the 10th percentile and above achieved the benchmark for spinal, epidural, and peripheral nerve block anesthetics and for new pain evaluations. CONCLUSIONS: The focus of US anesthesiology resident training in regional anesthesia and pain medicine has changed over the past 15 years by shifting from neuraxial to peripheral nerve block techniques. Previous training deficits have resolved for spinal anesthesia and peripheral nerve block. Procedural experience in pain medicine overwhelmingly involves epidural and facet injections.

Activation of cannabinoid receptor 2 attenuates mechanical allodynia and neuroinflammatory responses in a chronic post-ischemic pain model of complex regional pain syndrome type I in rats.

Complex regional pain syndrome type 1 (CRPS-I) remains one of the most clinically challenging neuropathic pain syndromes and its mechanism has not been fully characterized. Cannabinoid receptor 2 (CB2) has emerged as a promising target for treating different neuropathic pain syndromes. In neuropathic pain models, activated microglia expressing CB2 receptors are seen in the spinal cord. Chemokine fractalkine receptor (CX3CR1) plays a substantial role in microglial activation and neuroinflammation. We hypothesized that a CB2 agonist could modulate neuroinflammation and neuropathic pain in an ischemia model of CRPS by regulating CB2 and CX3CR1 signaling. We used chronic post-ischemia pain (CPIP) as a model of CRPS-I. Rats in the CPIP group exhibited significant hyperemia and edema of the ischemic hindpaw and spontaneous pain behaviors (hindpaw shaking and licking). Intraperitoneal administration of MDA7 (a selective CB2 agonist) attenuated mechanical allodynia induced by CPIP. MDA7 treatment was found to interfere with early events in the CRPS-I neuroinflammatory response by suppressing peripheral edema, spinal microglial activation and expression of CX3CR1 and CB2 receptors on the microglia in the spinal cord. MDA7 also mitigated the loss of intraepidermal nerve fibers induced by CPIP. Neuroprotective effects of MDA7 were blocked by a CB2 antagonist, AM630. Our findings suggest that MDA7, a novel CB2 agonist, may offer an innovative therapeutic approach for treating neuropathic symptoms and neuroinflammatory responses induced by CRPS-I in the setting of ischemia and reperfusion injury.

Development of technologies for placement of perineural catheters.

Continuous peripheral nerve block (CPNB) success is largely dependent on placement of the catheter close enough to the nerve to allow effective and sustained analgesia following painful surgeries with a minimum volume of local anesthetic. One of the most common problems associated with CPNB involves accurate placement of the catheter tip, migration, and dislodgement of the catheter. This is of increasing importance now that catheters are left in place for prolonged periods of time to provide postoperative analgesia, and patients with peripheral nerve catheters are being discharged home with ambulatory pumps. In response to the challenges of providing safe, effective, and consistently reliable analgesia, research and development in this field is expanding rapidly. This review article presents results from recent publications addressing the subject of peripheral nerve catheter localization.

Safeguards to prevent neurologic complications after epidural steroid injections: consensus opinions from a multidisciplinary working group and national organizations.

BACKGROUND: Epidural corticosteroid injections are a common treatment for radicular pain caused by intervertebral disc herniations, spinal stenosis, and other disorders. Although rare, catastrophic neurologic injuries, including stroke and spinal cord injury, have occurred with these injections. METHODS: A collaboration was undertaken between the U.S. Food and Drug Administration Safe Use Initiative, an expert multidisciplinary working group, and 13 specialty stakeholder societies. The goal of this collaboration was to review the existing evidence regarding neurologic complications associated with epidural corticosteroid injections and produce consensus procedural clinical considerations aimed at enhancing the safety of these injections. U.S. Food and Drug Administration Safe Use Initiative representatives helped convene and facilitate meetings without actively participating in the deliberations or decision-making process. RESULTS: Seventeen clinical considerations aimed at improving safety were produced by the stakeholder societies. Specific clinical considerations for performing transforaminal and interlaminar injections, including the use of nonparticulate steroid, anatomic considerations, and use of radiographic guidance are given along with the existing scientific evidence for each clinical consideration. CONCLUSION: Adherence to specific recommended practices when performing epidural corticosteroid injections should lead to a reduction in the incidence of neurologic injuries.

Acute pain in undergraduate medical education: an unfinished chapter!

Inadequately treated acute pain is a global healthcare problem that causes significant patient suffering and disability, risk of chronicity, increased resource utilization, and escalating healthcare costs. Compounding the problem is the lack of adequate instruction in acute pain management available in medical schools worldwide. Incorporating acute pain diagnosis and management as an integral part of the medical school curriculum will allow physicians to develop a more comprehensive, compassionate approach to treating patients with acute pain syndromes and should be considered a healthcare imperative. In this article, we review the current status of pain education in educational institutions across the world, focusing on achievements, lacunae, and inadequacies. We appeal to all concerned--pain management specialists, health educators, and policymakers--to consider incorporating education on acute pain and its management at undergraduate medical levels in an integrated manner.

Triple-blind randomized clinical trial of time until sensory change using 1.5% mepivacaine with epinephrine, 0.5% bupivacaine, or an equal mixture of both for infraclavicular block.

BACKGROUND AND OBJECTIVES: Practitioners mix faster-onset, intermediate-duration local anesthetics (LAs) with slower-onset, long-duration LAs to get fast peripheral nerve block (PNB) onset and long duration. We hypothesized that 1.5% mepivacaine (with epinephrine) (mepivacaine) or 1.5% mepivacaine (with epinephrine) mixed with 0.5% bupivacaine (mixed) would reduce PNB sensory onset by 20% or more versus 0.5% bupivacaine alone (bupivacaine). METHODS: Patients (n = 93) having arm surgery were randomized to 1 of the 3 LA groups. Infraclavicular PNB was administered using 1 of 3 LAs; afterward, PNB sensory (motor) onset, duration, and other outcomes were assessed. Subjects, physicians, and the biostatistician were blinded until study completion. RESULTS: Median (interquartile range) PNB sensory onset (in minutes) was as follows: mepivacaine, 3 (3-6); mixed, 6 (3-6); and bupivacaine, 6 (3-12) (P = 0.0085). Mepivacaine PNB sensory onset was not faster than mixed (P = 0.57), but mixed was faster than bupivacaine (P = 0.0035). More mixed group patients achieved PNB sensory onset (0.81) versus the bupivacaine group (0.54) at 6 mins. Median (interquartile range) PNB motor onset (in minutes) was as follows: mepivacaine, 15 (12-18); mixed, 17 (12-21); and bupivacaine, 21 (12-24) (P < 0.0001). Median sensory and motor PNB duration (in minutes) was as follows: mepivacaine, 281 and 320; mixed, 439 and 556; and bupivacaine, 850 and 1109. Sensory (motor) PNB duration was shorter with mepivacaine versus mixed (P < 0.0001, P = 0.034), and mixed was shorter versus bupivacaine (P = 0.0243, P = 0.034). CONCLUSIONS: Mixing 1.5% mepivacaine (with epinephrine) with 0.5% bupivacaine speeds up PNB sensory (motor) onset compared with 0.5% bupivacaine alone.

Guideline warfare over interventional therapies for low back pain: can we raise the level of discourse?

UNLABELLED: As guidelines proliferate and are used to inform efforts to improve the quality and efficiency of care, disputes over guideline recommendations are likely to become more common and contentious. It is appropriate for guidelines to come under close scrutiny, given their important clinical and policy implications, and critiques that point out missing evidence, improper methods, or errors in interpretation can be valuable. But for critiques to be valid, they should be based on accurate information and a sound scientific basis. A 2009 guideline sponsored by the American Pain Society (APS) on the use of invasive tests and interventional procedures found insufficient evidence to make recommendations for most interventional procedures. It was subsequently the subject of lengthy critiques by the American Society of Interventional Pain Physicians (ASIPP) that sought to challenge the methods used to develop the APS guideline, point out alleged errors in the evidence review commissioned to inform the guideline, and question the integrity of the APS guideline process. We show that the ASIPP critiques contain numerous errors and fail to adhere to scientific standards for reviewing evidence, and provide suggestions on how future disputes regarding guidelines might be addressed in a more constructive manner. PERSPECTIVE: In order to best serve patients and clinicians, debates over guidelines should be based on accurate information, adhere to current methodological standards, acknowledge important deficiencies in the evidence when they are present, and handle conflicts of interest in a vigorous and transparent manner.

5. Cervical facet pain.

More than 50% of patients presenting to a pain clinic with neck pain may suffer from facet-related pain. The most common symptom is unilateral pain without radiation to the arm. Rotation and retroflexion are frequently painful or limited. The history should exclude risk factors for serious underlying pathology (red flags). Radiculopathy may be excluded with neurologic testing. Direct correlation between degenerative changes observed with plain radiography, computerized tomography, and magnetic resonance imaging and pain has not been proven. Conservative treatment options for cervical facet pain such as physiotherapy, manipulation, and mobilization, although supported by little evidence, are frequently applied before considering interventional treatments. Interventional pain management techniques, including intra-articular steroid injections, medial branch blocks, and radiofrequency treatment, may be considered (0). At present, there is no evidence to support cervical intra-articular corticosteroid injection. When applied, this should be done in the context of a study. Therapeutic repetitive medial branch blocks, with or without corticosteroid added to the local anesthetic, result in a comparable short-term pain relief (2 B+). Radiofrequency treatment of the ramus medialis of the cervical ramus dorsalis (facet) may be considered. The evidence to support its use in the management of degenerative cervical facet joint pain is derived from observational studies (2 C+).

Clinical presentation of local anesthetic systemic toxicity: a review of published cases, 1979 to 2009.

The classic description of local anesthetic systemic toxicity (LAST) generally described in textbooks includes a series of progressively worsening neurologic symptoms and signs occurring shortly after the injection of local anesthetic and paralleling progressive increases in blood local anesthetic concentration, culminating in seizures and coma. In extreme cases, signs of hemodynamic instability follow and can lead to cardiovascular collapse. To characterize the clinical spectrum of LAST and compare it to the classic picture described above, we reviewed published reports of LAST during a 30-year period from 1979 to 2009. Ninety-three cases were identified and analyzed with respect to onset of toxicity and the spectrum of signs and symptoms. Sixty percent of cases followed the classic pattern of presentation. However, in the remainder of cases, symptoms were substantially delayed after the injection of local anesthetic, or involved only signs of cardiovascular compromise, with no evidence of central nervous system toxicity. Although information gained from retrospective case review cannot establish incidence, outcomes, or comparative efficacies of treatment, it can improve awareness of the clinical spectrum of LAST and, theoretically, the diagnosis and treatment of affected patients. The analytic limitations of our method make a strong case for developing a prospective, global registry of LAST as a robust alternative for educating practitioners and optimizing management of LAST.

ASRA practice advisory on local anesthetic systemic toxicity.

The American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity assimilates and summarizes current knowledge regarding the prevention, diagnosis, and treatment of this potentially fatal complication. It offers evidence-based and/or expert opinion-based recommendations for all physicians and advanced practitioners who routinely administer local anesthetics in potentially toxic doses. The advisory does not address issues related to local anesthetic-related neurotoxicity, allergy, or methemoglobinemia. Recommendations are based primarily on animal and human experimental trials, case series, and case reports. When objective evidence is lacking or incomplete, recommendations are supplemented by expert opinion from the Practice Advisory Panel plus input from other experts, medical specialty groups, and open forum. Specific recommendations are offered for the prevention, diagnosis, and treatment of local anesthetic systemic toxicity.

Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition).

The actual incidence of neurologic dysfunction resulting from hemorrhagic complications associated with neuraxial blockade is unknown. Although the incidence cited in the literature is estimated to be less than 1 in 150,000 epidural and less than 1 in 220,000 spinal anesthetics, recent epidemiologic surveys suggest that the frequency is increasing and may be as high as 1 in 3000 in some patient populations.Overall, the risk of clinically significant bleeding increase with age,associated abnormalities of the spinal cord or vertebral column, the presence of an underlying coagulopathy, difficulty during needle placement,and an indwelling neuraxial catheter during sustained anticoagulation( particularly with standard heparin or low-molecular weight heparin). The need for prompt diagnosis and intervention to optimize neurologic outcome is also consistently reported. In response to these patient safety issues, the American Society of Regional Anesthesia and Pain Medicine (ASRA) convened its Third Consensus Conference on Regional Anesthesia and Anticoagulation. Practice guidelines or recommendations summarize evidence-based reviews. However, the rarity of spinal hematoma defies a prospective randomized study, and there is no current laboratory model. As a result,the ASRA consensus statements represent the collective experience of recognized experts in the field of neuraxial anesthesia and anticoagulation. These are based on case reports, clinical series, pharmacology,hematology, and risk factors for surgical bleeding. An understanding of the complexity of this issue is essential to patient management.