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.

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.

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.

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.

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+).

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.

Ganglionic local opioid application (GLOA) for treatment of chronic headache and facial pain.

OBJECTIVE: This report describes the effects of ganglionic local opioid application (GLOA) in patients with chronic headache and persistent idiopathic facial pain. CASE REPORT: We present 2 patients with chronic headaches and 1 patient with persistent idiopathic facial pain who were refractory to medical treatment. These patients responded well to a series of ganglionic local opioid applications (GLOAs) by administration of buprenorphine. The beneficial effect of GLOA was manifested by a decrease in pain intensity, reduction of pain medications, and improvement in quality of life. CONCLUSIONS: These results support the theory of sympathetically mediated pain in the head and face, the presence of opioid receptors on the sympathetic ganglia, and a possible beneficial role of opioids in modulation of this process. To our knowledge, this case series is the first case series in the English literature of the use of GLOA at the stellate ganglion for head-and-face pain.

Acute post-surgical pain management: a critical appraisal of current practice, December 2-4, 2005.

The Acute Pain Summit 2005 was convened to critically examine the perceptions of physicians about current methods used to control postoperative pain and to compare those perceptions with the available scientific evidence. Clinicians with expertise in treatment of postsurgical pain were asked to evaluate 10 practice-based statements. The statements were written to reflect areas within the field of acute-pain management, where significant questions remain regarding everyday practice. Each statement made a specific claim about the usefulness of a specific therapy (eg, PCA or epidural analgesia) or the use of pain-control modalities in specific patient populations (eg, epidural analgesia after colon resection). Members of the American Society of Regional Anesthesia and Pain Medicine (ASRA) were asked, via a Web-based survey, to rate their degree of agreement with each of the 10 statements; 22.8% (n = 632) of members responded. In preparation for the pain summit, a panel member independently conducted a literature search and summarized the available evidence relevant to each statement. Summit participants convened in December 2005. The assigned panel member presented the available evidence, and workshop participants then assigned a category for the level of evidence and recommendation for each statement. All participants then voted about each statement by use of the same accept/reject scale used earlier by ASRA members. This manuscript details those opinions and presents a critical analysis of the existing evidence supporting new and emerging techniques used to control postsurgical pain.

Long-term outcomes during treatment of chronic pain with intrathecal clonidine or clonidine/opioid combinations.

To evaluate the effectiveness of intrathecal clonidine or clonidine/opioid admixture for the treatment of chronic pain states, a retrospective chart audit of 15 patients seen by the Pain Medicine and Neurosurgical Services was performed. Subjects included 9 men and 6 women aged 26-86 years. Diagnoses included complex regional pain syndrome, neuropathic pain, and cancer pain. All patients received a trial of single-shot and/or short-term infusion of clonidine. Those reporting a significant reduction in pain, or at least 50% reduction in their visual analog scale (VAS), received long-term therapy. Intrathecal clonidine as a single-shot dose, infusion, or as intrathecal polytherapy did not improve VAS scales from pre-treatment values in 5 patients. Ten patients reported significant pain relief or >50% decrease in VAS scores with the initial trial and received long-term therapy. Two received clonidine alone for 7-11 months before the therapy failed; others failed after just a few days. Seven of eight initially responded to clonidine alone (75-950 microg/day) before failing and requiring a second drug. Three received hydromorphone (200-8000 microg/day) and four morphine (0.15-15 mg/day) with clonidine. Four patients then failed 2-drug therapy (duration 6-21 months). Two continue with intrathecal clonidine/hydromorphone (duration 19-29 months) and 1 with clonidine/morphine (duration 21 months). After initiation of intrathecal clonidine, one patient reported good relief with clonidine/morphine until his death 5 months later. In this population, intrathecal clonidine was of limited utility for most patients. It may be of benefit for subset(s) of patients, but in our experience, duration of relief is typically <18 months.

Postoperative pain guidelines.

BACKGROUND AND OBJECTIVES: Postoperative pain is the expected but nonetheless undesirable byproduct of all surgical procedures. Humanitarian concerns and recent quasi-governmental regulations have heightened awareness about the importance of treating postoperative pain. This guideline builds upon the foundation created by the Agency for Health Care Policy and Research guideline published in 1993, highlights changes that have occurred over the past 10 years, and makes recommendations based on the current scientific evidence. In addition, it takes advantage of the versatile information management inherent in a web-based format to make the information readily available. METHODS: A multidisciplinary group of physicians, dentists, nurses, pharmacists, physical therapists, psychologists, and ethicists from the Veterans Health Administration (VHA) and Department of Defense (DoD) in conjunction with the VHA Office of Quality and Performance and a consultant group developed a postoperative pain algorithm and supporting documentation. The guideline structure and content were determined by a standardized rating of the evidence gleaned from comprehensive electronic searches. RESULTS: An interactive electronic and traditional "paper" guideline with a pre- and postoperative algorithm was developed. A table, which provides a menu of analgesic choices organized by specific operation, was constructed. Preferences for particular analgesic techniques and classes of medications were identified. A postoperative pain interactive pharmacopoeia and printable patient educational materials were also provided. The guideline may be reviewed at the following website: www.oqp.med.va.gov/cpg/cpg.htm. CONCLUSIONS: This postoperative pain guideline provides readily accessible information and evidence-based guidance to a variety of providers. It highlights deficiencies in our understanding of the pain and recovery processes and how they might guide our choices of postoperative analgesic techniques. In combination with the powerful system-wide data collection capabilities of the VHA, there may be improved understanding of what techniques are useful. Finally, it may lead to the development of reliable, individualized analgesic plans for specific surgical procedures that incorporate the full range of pharmacologic and nonpharmacologic techniques.

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.