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Peripheral nerve stimulation (PNS) was the first application of neuromodulation. Widespread application of PNS was limited by technical concerns. Recent advances now allow the percutaneous placement of leads with ultrasound or fluoroscopic guidance, while the transcutaneous powering of these leads removes the need for leads to cross major joints. This systematic review was written to assess the current status of high-quality evidence supporting the use of PNS for pain conditions treated by interventional pain physicians. The available literature on PNS, limited to conditions treated by interventional pain physicians, was reviewed and the quality assessed. Literature from 1966 to June 2021 was reviewed. The outcome measures were pain relief and functional improvement. One hundred and two studies were identified. Five randomized controlled trials (RCT) and four observational studies, all case series, met the inclusion criteria. One RCT was of high quality and four were of moderate quality; all four case series were of moderate quality. Three of the RCTs and all four case series evaluated peripheral nerve neuropathic pain. Based upon these studies, there is level II evidence supporting the use of PNS to treat refractory peripheral nerve injury. One moderate-quality RCT evaluated tibial nerve stimulation for pelvic pain, providing level III evidence for this indication. One moderate-quality RCT evaluated surgically placed cylindrical leads for cluster headaches, providing level III evidence for this indication. The evidence suggests that approximately two-thirds of patients with peripheral neuropathic pain will have at least 50% sustained pain relief. Adverse events from PNS are generally minor. A major advantage of PNS over spinal cord stimulation is the absence of any risk of central cord injury. The study was limited by the paucity of literature for some indications. No studies dealt with joint-related osteoarthritic pain. Supplementary Information The online version contains supplementary material available at 10.1007/s40122-021-00306-4.

Supplemental Digital Content is Available in the Text., Spinal cord stimulation (SCS) is an interventional nonpharmacologic treatment used for chronic pain and other indications. Methods for evaluating the safety and efficacy of SCS have evolved from uncontrolled and retrospective studies to prospective randomized controlled trials (RCTs). Although randomization overcomes certain types of bias, additional challenges to the validity of RCTs of SCS include blinding, choice of control groups, nonspecific effects of treatment variables (eg, paresthesia, device programming and recharging, psychological support, and rehabilitative techniques), and safety considerations. To address these challenges, 3 professional societies (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials, Institute of Neuromodulation, and International Neuromodulation Society) convened a meeting to develop consensus recommendations on the design, conduct, analysis, and interpretation of RCTs of SCS for chronic pain. This article summarizes the results of this meeting. Highlights of our recommendations include disclosing all funding source and potential conflicts; incorporating mechanistic objectives when possible; avoiding noninferiority designs without internal demonstration of assay sensitivity; achieving and documenting double-blinding whenever possible; documenting investigator and site experience; keeping all information provided to patients balanced with respect to expectation of benefit; disclosing all information provided to patients, including verbal scripts; using placebo/sham controls when possible; capturing a complete set of outcome assessments; accounting for ancillary pharmacologic and nonpharmacologic treatments in a clear manner; providing a complete description of intended and actual programming interactions; making a prospective ascertainment of SCS-specific safety outcomes; training patients and researchers on appropriate expectations, outcome assessments, and other key aspects of study performance; and providing transparent and complete reporting of results according to applicable reporting guidelines.

Peripheral nerve entrapments can occur anywhere in the head and body and can cause significant pain. Cancer pain can be caused by these entrapments, triggered by a variety of etiologies, including tumor invasion, surgical trauma, chemotherapy, or scarring. Knowing the cause of pain can help the physician treat the problem effectively, and will decrease unnecessary and potentially worsening surgeries and high dose opioid therapies, as well as unnecessary pain. A knowledgeable interventional pain physician can diagnose and treat these nerves entrapments in the most effective manner, providing improved pain relief and quality of life.Key points Nerve entrapments can occur throughout the body in cancer patients due to multiple etiologies such as tumor invasion, surgical trauma, or cancer therapy. The problem of nerve entrapments in cancer pain is under-recognized. Patients with nerve entrapment syndromes frequently complain of a burning tingling sensation and other paresthesias in the nerve distribution which can progress to a complete loss of sensory and motor function. Diagnostic tools include history and physical exam, imaging, nerve conduction studies as well as diagnostic nerve injections/blocks. Treatment of nerve entrapments can range from neuropathic pain medications to nerve blocks and nerve ablations to surgical decompression.

There are multiple peripheral nerve problems that can mimic or co-exist with thoracic outlet syndrome (TOS), including primary or secondary pathology related to the suprascapular, axillary, dorsal scapular, long thoracic, and spinal accessory nerves. Failure to recognize these problems can lead to inadequate or failed TOS treatment. This chapter discusses the anatomy, entrapment, diagnosis, and types of treatment of the suprascapular, axillary, dorsal scapular, long thoracic, and spinal accessory nerves. It should be noted that this chapter deals with the diagnosis and treatment of primary entrapment syndromes encountered during the workup of patients with cervicobrachial syndrome.

Cervicogenic headaches are a significant cause of head and neck pain, and occipital neuralgia is a common component of these cervicogenic headaches. Occipital injections are commonly performed at the occipital ridge, but this site does not address more proximal entrapments of the nerve in the suboccipital region. Because of the potentially dangerous structures in this region, clinicians have tended to avoid the suboccipital region, despite the pathologies seen in this region. This article discusses the pathology of the region, the alternative techniques, and the novel interventional approach developed for this region, specifically the “Stealth” approach of occipital decompression.

Patients see their primary care physicians (PCPs) for a variety of medical conditions, chronic pain being one of the most common. An increased use of prescription medications (especially opioids) has led to an increase in adverse drug reactions and has heightened our awareness of the variability in response to medications. Opioids and other pain adjuvants are widely used, and drug–drug interactions involving these analgesics can be problematic and potentially lethal. Pharmacogenetics has improved our understanding of drug efficacy and response, opened doors to individual tailoring of medical management, and created a series of ethical and economic considerations. Since it is a relatively new field, genetic testing has not been fully integrated into the primary care setting. The purpose of this paper is to review the metabolism of commonly prescribed opioids, discuss the economic and ethical issues, and provide PCPs with an understanding of how to incorporate genetic testing into routine use to improve clinical practice and patient management.

Chronic pain management techniques have evolved in recent years. With regard to this, ultrasound (US) technology has become a standard for most acute pain procedures and essential for postsurgical pain relief and enhanced recovery after surgery protocols. This manuscript summarizes clinical studies evaluating US use for chronic pain management and compares efficacy with standard techniques including fluoroscopy (FL). US possesses several unique benefits when compared with FL, including elimination of radiation exposure while providing similar clinical outcomes. In summary, US use for chronic pain procedures is emerging as a viable, safe, and effective modality. Additional studies are needed to best appreciate US and its role in chronic pain management.

Pain after limb amputation is frequently challenging to adequately treat with local anesthetic-based regional anesthesia techniques due to its relatively long duration. Furthermore, uncontrolled pain in the immediate postoperative period is associated with persistent postsurgical pain, and frequently phantom limb pain. Cryoneurolysis is an alternative regional analgesic method to local anesthesia-based techniques. We report 3 cases in which ultrasound-guided percutaneous cryoneurolysis was performed in the perioperative period of limb amputation. All reported profound analgesia in the postoperative period without persistent postsurgical residual limb or phantom pain in the following months. No adverse events associated with the cryoneurolysis procedure occurred.

Myofascial pain syndrome (MPS) is a common pain condition and one of a spectrum of soft tissue pain syndromes (Mense and Gerwin, Muscle pain: understanding the mechanisms. Springer, New York, 2010). Patients can demonstrate pain in one or more body regions associated with referred pain to a site not associated with the pain source. Taut muscle bands and especially myofascial trigger points (MTrPs) are the key components of the diagnosis, which is mostly clinical. MPS can be acute or chronic and can be associated with additional pain syndromes such as cervical facet joint syndrome and headaches. An excessive release of acetylcholine (ACh) plays a role in the pathophysiology, triggering more muscle spasms and the release of biologically active molecules, leading to peripheral and central sensitization. Therapy is usually multimodal with physical modalities including stretching exercises and trigger point injection therapy.

IntroductionCryoneurolysis is the direct application of low temperatures to reversibly ablate peripheral nerves to provide pain relief. Recent development of a handheld cryoneurolysis device with small gauge probes and an integrated skin warmer broadens the clinical applications to include treatment of superficial nerves, further enabling treatments for pre-operative pain, post-surgical pain, chronic pain, and muscle movement disorders.Areas coveredCryoneurolysis is the direct application of cold temperatures to a peripheral nerve, resulting in reversible ablation due to Wallerian degeneration and nerve regeneration. Use over the last 50 years attests to a very low incidence of complications and adverse effects. Cryoprobes have traditionally been applied through a surgical incision; but, recent technical advances allow percutaneous administration. A new hand-held device is now approved for use within the United States. Cryoneurolysis has been used to treat postoperative and chronic pain states as well as spasticity. Expert commentary: Changes in the US healthcare system such as a push for the reduction of opioid use and the incorporation of Diagnostic Related Group codes, as well as recent technological advances including a handheld unit that allows for treatment of superficial nerves while protecting the skin from damage, may contribute to the resurgence of cryoneurolysis for the treatment of peripheral nerves.

Study design Description of a new technique. Objectives To describe a safe ultrasound (US)-guided cryoneuroablation technique of the proximal greater occipital nerve (GON). Background Cryoneuroablation is a treatment option for occipital neuralgia, providing more sustained relief when steroid injections fail. US can identify the proximal GON between the C2 spinous and C1 transverse process over the inferior oblique capitis muscle (IOCM), where the GON is clearly visualized. US-guided GON injections are often performed with an out-of-plane approach; however, that approach is difficult with cryoneuroablation, because the probe has no opening (prohibiting hydrodissection), and the size and dullness of the probe hinders easy manipulation. Setting University-based outpatient pain clinic. Methods We provide a description of the procedure based on experience in the authors' clinic. With the patient in the prone position, the US probe is placed parallel to the IOCM. The GON is seen on top of the IOCM; a midline 2-mm incision allows access to the bilateral GONs with a single skin entry. Using an in-plane approach, the cryo probe is advanced to the nerve in a medial-to-lateral direction, with constant US visualization, staying far away from the spinal cord and vertebral artery, which increases safety. Conclusions Based on anecdotal evidence from the authors' clinic, cryoneuroablation of the proximal GON can be performed safely at the level of the IOCM. Limitations The procedure described is based on anecdotal evidence from a small number of patients; however, the procedure is promising and formal study is warranted.

Complex regional pain syndrome (CRPS) is a chronic debilitating pain condition of the extremities; it can affect, less commonly, other areas of the body (face, pelvis, abdomen). Its early presentation—pain disproportionate to the injury, skin temperature changes, hyperalgesia, allodynia—is often not recognized, delaying treatment. In later phases, with sympathetic nervous system involvement, it presents with skin and muscle atrophy, hair loss, allodynia, loss of function, and decreased range of motion. In severe cases, it can spread from one area to the other. Imaging findings (X-ray, MRI, bone scintigraphy) are nonspecific. They are used to support the diagnosis, and to exclude conditions that can present similarly. Treatment is challenging and includes physical therapy, psychologic support, medication management, and minimally invasive interventions to decrease pain, to positively influence the sympathetic nervous system, and to preserve function. A multidisciplinary approach is likely to be the most beneficial.

Tendinopathy is characterized by failure of the normal tendon repair mechanism, and is a common malady that leads to chronic pain. Although pain relief is an important goal in treating the patient with tendinopathy, modalities that are intended to decrease pain in the short term do not address the underlying tissue disorder. As no current gold standard exists in the treatment of tendinopathy, physicians face a unique challenge in treating this common pathology. Regenerative medicine applications in pain medicine aim to address this unique challenge.

Prolotherapy, or fibroproliferative therapy, is a regenerative injection therapy, first popularized in the 1940s and 1950s. Unfortunately, the combination of “better” surgical techniques and a series of high-profile medical catastrophes by poorly trained providers relegated the technique into the “fringe” arena. However, recent recognition of the failure of surgical interventions, combined with better technology and a burgeoning interest in the continuum of regenerative injection options, has renewed the interest and research into this “old” technique.

Persistent anterior knee pain, especially after surgery, can be very frustrating for the patient and the clinician. Injury to the infrapatellar branch of the saphenous nerve (IPS) is not uncommon after knee surgeries and trauma, yet the diagnosis and treatment of IPS neuralgia is not usually taught in pain training programs. In this case report, we describe the anatomy of the saphenous nerve and specifically the infrapatellar saphenous nerve branch; we also discuss the types of surgical trauma, the clinical presentation, the diagnostic modalities, the diagnostic injection technique, and the treatment options. As early as 1945, surgeons were cautioned regarding the potential surgical trauma to the IPS. Although many authors dismissed the nerve damage as unavoidable, the IPS is now recognized as a potential cause of persistent anterior and anteriomedial knee pain. Even more concerning, damage to peripheral nerves such as the IPS has been identified as the cause and potential perpetuating factor for conditions such as complex regional pain syndromes (CRPS). Because the clinical presentation may be vague, it has often been misdiagnosed and underdiagnosed. There is a documented vasomotor instability, but, unfortunately, sympathetic blocks will not address the underlying pathology, and therefore patients often will not respond to this modality, although the correct diagnosis can lead to rapid and gratifying resolution of the pathology. An entity unknown to the clinician is never diagnosed, and so it is important to familiarize pain physicians with IPS neuropathy so that they may be able to offer assistance when this painful condition arises. Key words: infrapatellar saphenous nerve, saphenous neuralgia, nerve injury, knee pain, postoperative pain, peripheral nerve entrapment, diagnostic nerve blocks, complex regional pain syndrome, cryoneuroablation

The pathophysiology of phantom limb pain (PLP) is multifactorial. It probably starts in the periphery and is amplified and modified in the central nervous system. A small group of patients with PLP were questioned as to the portion of the phantom limb affected by pain (e.g., "great toe," "thumb"). In the stump, the corresponding amputated nerve was located with a nerve stimulator. With correct placement and stimulation, the PLP could then be reproduced or exacerbated. A small dose of local anesthesia was then injected, resulting in the disappearance of the PLP. If a peripheral nerve injection gave temporary relief, our final treatment was cryoanalgesia at this location. Evaluation of 5 patients, followed for at least 2.5 years, yielded the following results: 3 patients had excellent results (100%, 95%, and 90% decrease in complaints, respectively), 1 patient had an acceptable result (40% decrease), and 1 patient had only a 20% decrease in pain. Although both central and peripheral components are likely involved in PLP, treatment of a peripheral pain locus with cryoanalgesia should be considered. We propose the identification of a peripheral etiology may help match patients to an appropriate therapy, and cryoanalgesia may result in long-term relief of PLP.

Superficial radial neuralgia is an under-recognized cause of radial wrist and thumb pain. It is misdiagnosed as wrist tendonitis, DJD of the thumb, carpal tunnel syndrome, lateral epicondylitis, and cervical radiculopathy. Careful attention to the presentation and physical exam will reveal the etiology, which will lead to a variety of treatment options.

Peripheral nerve entrapments are common and treatable sources of pain. These conditions are a significant cause of morbidity and disability in the general population. The epidemiology and pathophysiology of peripheral nerve entrapment are reviewed, highlighting the most important risk factors and mechanisms leading to peripheral nerve entrapment.

The greater occipital nerve (GON) entrapment commonly causes occipital and cervicogenic headaches and can sometimes cause headaches with similar characteristics to migraine headaches. Diagnosis is made by physical examination of the neck and injection of local anesthetic. Treatment for GON includes medications, nerve injections, cryoneuroablation, radiofrequency lesioning, neuromodulation, and surgical decompression.

The posterior tibial nerve is a portion of the sciatic nerve that runs down the posterior leg into the foot. It can be entrapped at two major sites: behind the knee at the proximal edge of the soleus muscle and at the ankle in the tarsal tunnel. The small terminal branches of the tibial nerve can be entrapped in the distal ankle and foot and are discussed in other chapters. Posterior tibial nerve entrapment can lead to pain and dysesthesias in the calf and sole of the foot, as well as dysfunction of the foot flexors and intrinsic muscles.

Auriculotemporal nerve (ATN) entrapment commonly causes pain around the ear and jaw and can have overlapping characteristics to migraine headaches. Diagnosis is made by physical examination of the temporal fossa and the temporomandibular joint and by injection of local anesthetic over the nerve. Treatment of ATN entrapment includes medications, nerve injections, cryoneuroablation, chemical neurolysis, neuromodulation, and surgical decompression.

The third occipital nerve (TON) is an under-recognized cause of occipital headaches and can sometimes cause headaches with similar characteristics to migraine headaches. Diagnosis is made by fluoroscopic injections of local anesthetic. Treatment for TON includes medications, nerve injections, cryoneuroablation, radiofrequency lesioning, neuromodulation, and surgical decompression.

Entrapment of the lumbar plexus is an under-recognized cause of pelvic, low back, abdominal, and leg pain. Due to the wide variety of entrapments, there can be a large variety of potentially confusing clinical presentations. The clinician needs to have a high index of suspicion to diagnose and therefore treat psoas entrapment of the lumbar plexus.

The lesser occipital nerve (LON) entrapment is an under-recognized cause of cervicogenic and occipital headaches and can sometimes cause headaches with similar characteristics to migraine headaches. Diagnosis is made by physical examination of the neck and injection of local anesthetic. Treatment for LON entrapment includes medications, injections, radiofrequency lesioning, neuromodulation, and surgical decompression.

Ulnar nerve entrapment can be a cause of elbow, wrist, and hand pain. The ulnar nerve travels through several canals or tunnels, and, like the better-known carpal tunnel syndrome, these tunnels can cause entrapment. It is commonly seen in patients participating in throwing sports, such as baseball. Two primary sites are seen in ulnar nerve entrapments – cubital tunnel and Guyon’s canal. Appropriate diagnosis is necessary for appropriate treatment, and ulnar entrapment should be considered in patients with weakness or clumsiness of the hand.

Because of the potentially dangerous structures in the suboccipital region (such as the foramen magnum and vertebral artery), clinicians have tended to avoid this area, despite the pathology often seen there. This chapter discusses the regional pathology, the alternative techniques, and a novel interventional approach, the “Stealth” approach, for occipital decompression.

The lateral plantar nerve is a cause of pain in the lateral sole and toes. Since this nerve can be entrapped as part of the tarsal tunnel syndrome as well as entrapped separately, it is important to carefully assess the site of entrapment; proximal treatment will not address distal pathology. Lateral plantar nerve entrapment may be treated with injection, neurolytic or surgical techniques.

Medial plantar nerve (MPN) entrapment can be a cause of medial foot pain and possible sensory loss over the anteromedial sole. This nerve may be entrapped within the tarsal tunnel as a part of tarsal tunnel syndrome, at the entrance to the medial plantar tunnel under the abductor hallucis muscle, or at the knot of Henry.

Entrapment of the obturator nerve is a little recognized and rarely taught cause of pelvic and groin/thigh/knee pain. In the pelvis, the obturator nerve can mimic pudendal neuralgia, hip pathology, groin strain, and claudication.

Peripheral nerve entrapment due to any cause may result in acute or chronic nerve injury. In nerves with a sensory component, the most common clinical consequence of peripheral nerve entrapments is pain. This pain typically is described as burning or lancinating, sharp, or knifelike, or like an ice pick, and is often intensely unpleasant. Neuralgia due to peripheral nerve entrapment may cause significant disability even in the setting of intact motor function, as the patient learns to avoid any motion or activity that might trigger this pain. Nerve entrapment can trigger, perpetuate, or mimic complex regional pain syndrome (CRPS). Less common sequelae of peripheral nerve entrapment include paresthesias, immobility, decreased sensation, and motor impairment.

This chapter includes a review of the clinical presentation, anatomy, pathophysiology, diagnostic examination, differential diagnosis, and treatment of pudendal entrapment. The majority of these patients are females with chronic pelvic pain, often treated ineffectively for years. With proper diagnosis, there are many treatment options available, including multiple injection alternatives and surgery.

Entrapment of the lumbosacral plexus is an under-recognized cause of lower extremity, pelvic, low back, and abdominal pain; because of the wide variety of entrapments, there can be a wide variety of potentially confusing clinical presentations. The clinician needs to have a high index of suspicion to diagnose and therefore treat psoas entrapment of the lumbosacral plexus.

The dorsal scapular nerve is a relatively unknown nerve entrapment that causes shoulder and arm pain. Because the nerve passes through the middle scalene muscle, it can be traumatized during brachial plexus injections. It can be a cause of thoracic outlet syndrome.

Supraorbital neuralgia is an uncommon cause of extracranial headache that presents with symptoms of unilateral or bilateral intermittent forehead pain with tenderness over the distribution of the supraorbital nerve. Occasionally, patients may present with other symptoms, like blurred vision, nausea, and photophobia, thus confusing the diagnosis with other syndromes like migraine type headaches, cluster headaches, or sinusitis. However, the most common causes are trauma to the forehead and fluid retention, both leading to entrapment of the supraorbital nerve. Treatment varies and should be directed to the cause itself. Treatment involves removing the irritating stimulus, medications, local anesthetic blockade, neurolysis of the nerve, neuromodulation, and surgical decompression.

Background: Human Immunodeficiency Virus (HIV) patients have an increased rate of chronic pain, particularly peripheral neuropathy. This disease burden causes considerable disability and negatively affects quality of life. Pain is undertreated and more complex to manage in these patients for a number of reasons, including complex anti-retroviral drug regimens, higher risks of side effects, and higher rates of comorbid psychiatric illness and substance abuse. Pain management must take these factors into account and use all available modalities, including nonopioid pain relievers, adjuvant medications, and psychosocial therapies in addition to opioid analgesics. Here we review recent recommendations regarding acute and chronic opioid treatment of pain and the treatment of opioid dependence in HIV-infected patients, and provide suggestions regarding aberrant behavior in pain treatment. Objectives: The objective of this comprehensive review is to assess and summarize the complicating factors involved in treating HIV patients’ pain with opioid analgesics. Study Design: This is a narrative review without a systematic quality assessment of the literature discussion. Methods: A comprehensive review of the literature relating to pain and pain treatment in HIV patients. The literature was collected from electronic databases, textbooks, and other sources. The scientific literature reviewed includes randomized trials, observational studies, systematic reviews, guidelines, and government reports. Results: This patient population is heterogeneous and diverse in their medical issues and comorbidities, but a systematic, stepwise approach to assessing and managing pain in HIV patients is described. Chronic opioid treatment has proven to be problematic and considerations and alternatives to this treatment are described. Management of pain in patients with opioid addiction, a frequent comorbidity of HIV infection, requires special awareness and different prescribing practices. Screening and identifying patients who are at special risk for developing medical or behavior complications of pain treatment is essential, and approaches to this, and common forms of aberrant behavior, are described. Limitations: The scientific literature on opioid treatment in this population is limited. The population of HIV patients is heterogeneous and differs in significant ways based on ethnicity, national origin, and mode of transmission, making it difficult to generalize about pain treatment in such a diverse group. Conclusions: Pain management in HIV patients must take these factors into account and use all available modalities for treatment, including nonopioid analgesics, adjuvant medications, and psychosocial therapies. Opioid analgesics should be prescribed with caution in accordance with current guidelines and after careful risk assessment. Key words: HIV, Human Immunodeficiency Virus, acute pain, chronic pain, psychiatric comorbidity, opioid dependence, opioids, chronic opioid therapy, substance abuse.

Robert J Balch, Andrea TrescotDepartment of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA USAAbstract: Morphine is the archetypal opioid analgesic. Because it is a short-acting opioid, its use has been limited to the management of acute pain. The development of extended-release formulations have resulted in the increased utilization of morphine in chronic pain conditions. This review documents the history of morphine use in pain treatment, and describes the metabolism, pharmacodynamics, formulations, and efficacy of the currently available extended-release morphine medications.Keywords: Morphine ER, sustained-release morphine, MSContin, Oramorph®, Kadian®, Avinza®, Embeda&reg

Background: Today, with the growing interest of the medical community and others in practice guidelines, there is greater emphasis on formal procedures and methods for arriving at a widely scrutinized and endorsed consensus than ever before. Conflicts in terminology and technique are notable for the confusion that guidelines create and for what they reflect about differences in values, experiences, and interests among different parties. While public and private development activities continue to multiply, the means for coordinating these efforts to resolve inconsistencies, fill in gaps, track applications and results, and assess the soundness of particular guidelines continue to be limited. In this era of widespread guideline development by private organizations, the American College of Occupational and Environment Medicine (ACOEM) has developed guidelines that evaluate areas of clinical practice well beyond the scope of occupational medicine and yet fail to properly involve physicians expert in these, especially those in the field of interventional pain management. As the field of guidelines suffers from imperfect and incomplete scientific knowledge as well as imperfect and uneven means of applying that knowledge without a single or correct way to develop guidelines, ACOEM guidelines have been alleged to hinder patient care, reduce access to interventional pain management procedures, and transfer patients into a system of disability, Medicare, and Medicaid. Objective: To critically appraise occupational medicine practice guidelines for interventional pain management by an independent review utilizing the Appraisal of Guidelines for Research and Evaluation (AGREE), American Medical Association (AMA), Institute of Medicine (IOM), and other commonly utilized criteria. Methods: Revised chapters of ACOEM guidelines, low back pain and chronic pain, developed in 2007 and 2008 are evaluated, utilizing AGREE, AMA, IOM instruments, and Shaneyfelt et al’s criteria, were independently reviewed by 4 appraisers. Results: Critical appraisal utilizing the AGREE instrument found that both chapters scored less than 10% in 3 of the 6 domains, less than 20% in one domain, over 30% in one domain, and over 70% in one domain. Global assessment also scored below 30% with a recommendation from AGREE, “not recommended or suitable for use in practice.” Based on AMA key attributes, both chapters of ACOEM guidelines met only one of the 6 key attributes, only 3 of the 8 attributes were met by IOM criteria, and based on the criteria described by Shaneyfelt et al, overall only 28% of criteria were met. Conclusion: Both the low back pain and chronic pain chapters of the ACOEM guidelines may not be ideal for clinical use based on the assessment by the AGREE instrument, AMA attributes, and criteria established by Shaneyfelt et al. They also scored low on IOM criteria (37.5%). These guidelines may not be applicable for clinical use. Key words: Evidence-based medicine, systematic reviews, guideline development, AHCPR, AHRQ, IOM, AMA, AGREE, workers’ compensation, guidelines, ACOEM, ASIPP, interventional pain management, interventional techniques, chronic pain guidelines, low back pain guidelines

Opioids are important, if not essential, agents in treating certain types of chronic pain. However, the prevalence of drug misuse, abuse, and addiction has fostered considerable consternation among physicians, who may hesitate to prescribe these medications both due to concern for patients (misuse, abuse, and addiction), and fears of prosecution and/or professional sanction. Such practice may reflect 1) inadequate knowledge about patients’ susceptibility to, or current drug misuse or abuse; 2) lack of familiarity with extant assessments and/or regulations, and/or 3) an unanticipated reaction to existing guidelines, policies or laws. We posit that assessing patients’ predisposition to, and patterns of, drug misuse/abuse is a vital first step toward establishing and maintaining the safe and effective use of opioid analgesics in the treatment of chronic pain. Adherence monitoring is critical to identify patients’ prior and current drug use, establish treatment basis, and evaluate compliance, so as to avoid misuse and abuse, and ensure sound and proper pain management. This paper provides a review of the numerous monitoring approaches that have been described in the literature and addresses the benefits and limitations of these techniques and tools. The complex nature of the problem of drug misuse and abuse is discussed, and while no single monitoring technique can fully address this complex issue, we describe how multiple approaches to adherence monitoring may be employed to sustain the prudent use of opioids for the treatment of chronic pain. Key words: Opioids, adherence monitoring, drug abuse, non-compliance, misuse, addiction, urine drug testing

Medications which bind to opioid receptors are increasingly being prescribed for the treatment of multiple and diverse chronic painful conditions. Their use for acute pain or terminal pain is well accepted. Their role in the long-term treatment of chronic noncancer pain is, however, controversial for many reasons. One of the primary reasons is the well-known phenomenon of psychological addiction that can occur with the use of these medications. Abuse and diversion of these medications is a growing problem as the availability of these medications increases and this public health issue confounds their clinical utility. Also, the extent of their efficacy in the treatment of pain when utilized on a chronic basis has not been definitively proven. Lastly, the role of opioids in the treatment of chronic pain is also influenced by the fact that these potent analgesics are associated with a significant number of side effects and complications. It is these phenomena that are the focus of this review. Common side effects of opioid administration include sedation, dizziness, nausea, vomiting, constipation, physical dependence, tolerance, and respiratory depression. Physical dependence and addiction are clinical concerns that may prevent proper prescribing and in turn inadequate pain management. Less common side effects may include delayed gastric emptying, hyperalgesia, immunologic and hormonal dysfunction, muscle rigidity, and myoclonus. The most common side effects of opioid usage are constipation (which has a very high incidence) and nausea. These 2 side effects can be difficult to manage and frequently tolerance to them does not develop; this is especially true for constipation. They may be severe enough to require opioid discontinuation, and contribute to under-dosing and inadequate analgesia. Several clinical trials are underway to identify adjunct therapies that may mitigate these side effects. Switching opioids and/or routes of administration may also provide benefits for patients. Proper patient screening, education, and preemptive treatment of potential side effects may aid in maximizing effectiveness while reducing the severity of side effects and adverse events. Opioids can be considered broad spectrum analgesic agents, affecting a wide number of organ systems and influencing a large number of body functions. Key words: Opioids, morphine, methadone, fentsnyl, oxycodone, hydrocodone, xymorphone, codeine, adverse events, narcotics, side effects, constipation, sedation, hearing loss, tolerance, addiction, hyperalgesia

Background: Opioid abuse has continued to increase at an alarming rate since our last opioid guidelines were published in 2005. Available evidence suggests a continued wide variance in the use of opioids, as documented by different medical specialties, medical boards, advocacy groups, and the Drug Enforcement Administration. Objectives: The objectives of opioid guidelines by the American Society of Interventional Pain Physicians (ASIPP) are to provide guidance for the use of opioids for the treatment of chronic non-cancer pain, to bring consistency in opioid philosophy among the many diverse groups involved, to improve the treatment of chronic non-cancer pain, and to reduce the incidence of abuse and drug diversion. Design: A broadly based policy committee of recognized experts in the field evaluated the available literature regarding opioid use in managing chronic non-cancer pain. This resulted in the formulation of the review and update of the guidelines published in 2006, a series of potential evidence linkages representing conclusions, followed by statements regarding the relationships between clinical interventions and outcomes. Methods: The elements of the guideline preparation process included literature searches, literature synthesis, consensus evaluation, open forum presentations, formal endorsement by the Board of Directors of the American Society of Interventional Pain Physicians, and peer review. Based on the criteria of the U.S. Preventive Services Task Force, the quality of evidence was designated as Level I, II, and III, with 3 subcategories in Level II, with Level I described as strong and Level III as indeterminate. The recommendations were provided from 1A to 2C, varying from strong recommendation with high quality evidence to weak recommendation with low-quality or very low-quality evidence. Results: After an extensive review and analysis of the literature, which included systematic reviews and all of the available literature, the evidence for the effectiveness of long-term opioids in reducing pain and improving functional status for 6 months or longer is variable. The evidence for transdermal fentanyl and sustained-release morphine is Level II-2, whereas for oxycodone the level of evidence is II-3, and the evidence for hydrocodone and methadone is Level III. There is also significant evidence of misuse and abuse of opioids. The recommendation is 2A – weak recommendation, high-quality evidence: with benefits closely balanced with risks and burdens; with evidence derived from RCTs without important limitations or overwhelming evidence from observational studies, with the implication that with a weak recommendation, best action may differ depending on circumstances or patients’ or societal values. Conclusion: Opioids are commonly prescribed for chronic non-cancer pain and may be effective for short-term pain relief. However, long-term effectiveness of 6 months or longer is variable with evidence ranging from moderate for transdermal fentanyl and sustained-release morphine with a Level II-2, to limited for oxycodone with a Level II-3, and indeterminate for hydrocodone and methadone with a Level III. These guidelines included the evaluation of the evidence for the use of opioids in the management of chronic non-cancer pain and the recommendations for that management. These guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Because of the changing body of evidence, this document is not intended to be a “standard of care.” Key words: Chronic pain, persistent pain, non-cancer pain, controlled substances, substance abuse, prescription drug abuse, dependency, opioids, prescription monitoring, drug testing, adherence monitoring, diversion

Background: Epidural injection of corticosteroids is one of the most commonly used interventions in managing chronic spinal pain. However, there has been a lack of well-designed randomized, controlled studies to determine the effectiveness of epidural injections. Consequently, debate continues as to the value of epidural steroid injections in managing spinal pain. Objective: To evaluate the effect of various types of epidural steroid injections (interlaminar, transforaminal, and caudal), in managing various types of chronic spinal pain (axial and radicular) in the neck and low back regions. Study Design: A systematic review utilizing the criteria established by the Agency for Healthcare Research and Quality (AHRQ) for evaluation of randomized and non-randomized trials, and criteria of Cochrane Musculoskeletal Review Group for randomized trials were used. Methods: Data sources included relevant English literature performed by a librarian experienced in Evidence Based Medicine (EBM), as well as manual searches of bibliographies of known primary and review articles and abstracts from scientific meetings within the last 2 years. Three reviewers independently assessed the trials for the quality of their methods. Subgroup analyses were performed among trials with different control groups, with different techniques of epidural injections (interlaminar, transforaminal, and caudal), with different injection sites (cervical/thoracic, lumbar/sacral), and with timing of outcome measurement (short- and long-term). Outcome Measures: The primary outcome measure is pain relief. Other outcome measures were functional improvement, improvement of psychological status, and return to work. Short-term improvement is defined as 6 weeks or less, and long-term relief is defined as 6 weeks or longer. Results: In managing lumbar radicular pain with interlaminar lumbar epidural steroid injections, the evidence is strong for short-term relief and limited for long-term relief. In managing cervical radiculopathy with cervical interlaminar epidural steroid injections, the evidence is moderate. The evidence for lumbar transforaminal epidural steroid injections in managing lumbar radicular pain is strong for short-term and moderate for long-term relief. The evidence for cervical transforaminal epidural steroid injections in managing cervical nerve root pain is moderate. The evidence is moderate in managing lumbar radicular pain in post lumbar laminectomy syndrome. The evidence for caudal epidural steroid injections is strong for short-term relief and moderate for long-term relief, in managing chronic pain of lumbar radiculopathy and postlumbar laminectomy syndrome. Conclusion: There is moderate evidence for interlaminar epidurals in the cervical spine and limited evidence in the lumbar spine for long-term relief. The evidence for cervical and lumbar transforaminal epidural steroid injections is moderate for long-term improvement in managing nerve root pain. The evidence for caudal epidural steroid injections is moderate for long-term relief in managing nerve root pain and chronic low back pain. Key words: Spinal pain, low back pain, cervicalgia, epidural steroids, interlaminar, caudal, transforaminal, radiculopathy, axial pain, postlaminectomy syndrome, failed back surgery syndrome.

Background: Available data have shown steady increases of drug overdose deaths between 1992 and 2011. We review evidenced-based recommendations provided by a few prominent North American pain societies and suggest ways on how health providers might help reduce opioid analgesic deaths by implementing these practices. Objective: To identify health care providers’ roles in reducing opioid analgesic deaths. Study Design: A comprehensive review of current literature. Methods: The review included relevant literature identified through searches of MEDLINE, Cochran reviews, and Google Scholar, PubMed and EMBASE from January 1998 to January 2014. The level of evidence was classified as I (good), II (fair), and III (limited) based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Results: Several practices such as too high doses overall, giving too high doses to opioid naive patients, too fast opioid titration, insufficient use and knowledge of urine drug testing, not updating knowledge of drug metabolism/interactions, and inadequate patient monitoring are associated with higher risks of opioid analgesic deaths. Suboptimal risk stratification of patients, rotation practices, and use of opioids analgesics in chronic noncancer pain are also associated factors. Limitations: There were a paucity of good evidence studies which show recommendations reduce death. Conclusion: Providers should be aware of all associated factors with opiate analgesic deaths and apply the available evidence in reducing opioid analgesic deaths. Key words: Opioid analgesic deaths, methadone deaths, opioid mortality, opioid guidelines, genetic testing for opioids, urine drug testing

Although interventional procedures should be used cautiously in the setting of chronic pain, there is a role for a variety of injections to facilitate a patient's overall rehabilitation program. There are many resources available, including a prior issue of Physical Medicine and Rehabilitation Clinics of North America, which discuss the more conventional spinal injections. The focus of this article is on lesser-known injection options for treating chronic pain. The authors separately discuss trigger point injections, regenerative injections (prolotherapy), and injections using botulin toxins.

Methadone, classically used to prevent withdrawal in heroin addicts, has relatively recently seen a significant increase in the use to treat chronic pain, especially neuropathic pain. Its lack of euphoria, its efficacy in treating neuropathic pain and opioid-induced hyperalgia, its inherently long action, and its low cost has fueled the increased use. Unfortunately, methadone also has several unique, potentially lethal qualities (cardiac arrhythmias, drug–drug interactions) that must be understood when prescribing this medication. This chapter reviews the uses, abuses, metabolism, drug interactions, genetics, precautions, and recommendations.

Interventional pain medicine is one of the fastest evolving branches of medical science. Among many interventional techniques in current use, regenerative injection therapy (RIT), aka prolotherapy or sclerotherapy, is a procedure to treat chronic musculoskeletal pain of connective tissues origin. RIT was originally employed to treat painful hypermobility of the peripheral joints secondary to ligament laxity, but fairly quickly evolved to include the treatment of axial joints as well as painful axial and peripheral enthesopathies. Despite arbitrary opposition from insurance carriers, RIT is slowly finding a place in the armamentarium of contemporary pain practitioners because of its effectiveness. Interventional techniques are defined as minimally invasive procedures for percutaneous delivery of therapeutic/diagnostic modalities to targeted areas for the treatment of chronic pain. Based on this definition, RIT is the oldest interventional technique in current use. RIT was originally employed to treat painful hypermobility of the peripheral joints secondary to ligament laxity, but fairly quickly evolved to include the treatment of axial joints as well as painful axial and peripheral enthesopathies. A common feature found in patients with chronic musculoskeletal pain is tenderness on palpation at certain sites, particularly where ligaments, tendons, or aponeuroses attach to bone. This phenomenon attracted the attention of early investigators, who developed a novel model of pathology and injection technique for its treatment. This chapter will emphasize some fundamental high-quality retrospective, prospective, and pilot studies omitted from recent narrow focused reviews, describe the pathogenesis and mechanism of action based on contemporary literature, and emphasize some of the practical clinical utilizations and technical aspects of RIT.

lation of the essentials of guidelines, a series of potential evidence linkages representing conclusions, followed by statements regarding relationships between clinical interventions and outcomes. Methods: Consistent with the Agency for Healthcare Research and Quality (AHRQ) hierarchical and comprehensive standards, the elements of the guideline preparation process included literature searches, literature synthesis, systematic review, consensus evaluation, open forum presentations, formal endorsement by the Board of Directors of the American Society of Interventional Pain Physicians (ASIPP), and blinded peer review. Evidence was designated based on scientifi c merit as Level I (conclusive), Level II (strong), Level III (moderate), Level IV (limited), or Level V (indeterminate). Results: After an extensive review and analysis of the literature, the authors utilized two systematic reviews, two narrative reviews, 32 studies included in prior systematic reviews, and 10 additional studies in the synthesis of evidence. The evidence was limited. Conclusion: These guidelines evaluated the evidence for the use of opioids in the management of chronic non-cancer pain and recommendations for management. These guidelines are based on the best available scientifi c evidence and do not constitute infl exible treatment recommendations. Because of the changing body of evidence, this document is not intended to be a “standard

For many years, headaches or “migraines” have been felt to be intracranial in nature. However, recently a large number of “migraines” have been found to be due to extracranial causes which are amenable to interventional pain techniques. Recognition of the causes of extracranial headaches will result in effective and rewarding headache treatment.

Pinal endoscopy is a minimally invasive ap- proach into the spinal canal to assist in diag- nosis and treatment of patients with low back and/or radicular pain. The technique allows diag- nosis, percutaneous lysis.of adhesions, and di- rected epidural steroid injections. In this article we will discuss the pertinent anatomy, clinical uses, patient selection, and complication avoidance. Low back pain has been a scourge of mankind since we moved from quadrupedal to bipedal am- bulation. Approximately, 15-20% of the US pop- ulation suffers from back pain every year, and 50% of working-age people report having a "back symptom" each year.: Multiple investigators have shown that as many as 79% of patients continue to have back pain 1 year after the onset of low back pain. ~ Back symptoms are the most common cause of disability in persons under the age of 45. At any given time, about I% of the US population is chronically disabled because of back problems, and another I% is temporarily disabled. Disability fi'om back pain has continued to increase at a steady pace since the 1950s. Low back problems are the second most common symptomatic reason expressed by patients to visit their primary care physician, and the most common reason for office visits to the orthopedic surgeon, neurosurgeon and occupational medicine physicians. Low back pain is the third most common reason for a surgical procedure. Even though most common surgical interventions for spinal pain pertain to the herni- ated disc, numerous studies have indicated that only 1% of severe episodes of low back pain is

Epidural injections with or without steroids are used extensively in the man- agement of chronic spinal pain. However, evidence is contradictory with continuing de- bate about the value of epidural steroid in- jections in chronic spinal syndromes. The objective of this systematic re- view is to determine the effectiveness of epi- dural injections in the treatment of chronic spinal pain. Data sources include relevant literature identified through searchs of MED - LINE, EMBASE (Jan 1966- Mar 2003), manual searches of bibliographies of known primary and review articles, and abstracts from sci- entific meetings. Both randomized and non- randomized studies were included in the re- view based on the criteria established by the Agency for Healthcare Research and Quality (AHRQ). Studies were excluded from the anal- ysis if they were simply review or descriptive and failed to meet minimum criteria. The results showed that there was strong evidence to indicate effectiveness of transforaminal epidural injections in manag- ing lumbar nerve root pain. Further, evidence was moderate for caudal epidural injections in managing lumbar radicular pain. The ev- idence in management of chronic neck pain, chronic low back pain, cervical radiculopathy, spinal stenosis, and post laminectomy syn- drome was limited or inconclusive. In conclusion, the evidence of effective- ness of transforaminal epidural injections in managing lumbar nerve root pain was strong, whereas, effectiveness of caudal epidural in- jections in managing lumbar radiculopathy was moderate, while there was limited or in- conclusive evidence of effectiveness of epi- dural injections in managing chronic spinal pain without radiculopathy, spinal stenosis, post lumbar laminectomy syndrome, and cer- vical radiculopathy.

Controlled substance abuse has increased at an alarming rate. However, available evidence suggests a wide variance in the use of controlled substances, as documented by different medical specialties, medical boards, advocacy groups, and the Drug Enforcement Administration. The primary objective of controlled substance guidelines by American Society of Interventional Pain Physicians (ASIPP) is to provide guidance for the use of controlled substances for the treatment of chronic pain. It is anticipated that these practical guidelines will improve quality of care, patient access, and quality of life. Additional benefits include improved treatment efficiency and efficacy, and cost containment by improving the risk-benefit ratio of treating patients with chronic pain. Further goals of this manuscript are to bring consistency in opioid philosophy among the many diverse groups involved, to improve the treatment of chronic pain patients with medically appropriate controlled substances, and to reduce the incidence of drug diversion. These guidelines also reinforce the need for systematic evaluation and ongoing care of patients with chronic or persistent pain. ASIPP controlled substance guidelines also provide a discussion of the epidemiology of chronic pain, the role of controlled substances in treating chronic pain, various aspects of drug abuse, pharmacological considerations, clinical effectiveness of controlled substances, options for treatment monitoring and drug testing and a review of terminology used in addiction medicine. These guidelines do not constitute inflexible treatment recommendations. It is expected that a provider will establish a plan of care on a case-by-case basis, taking into account an individual patient's medical condition, personal needs, and preferences, and the physician's experience. Based on an individual patient's needs, controlled substance prescribing and treatment different from that outlined here may be warranted. These guidelines do not represent "standard of care."