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Central neuropathic pain, which is pain caused by a lesion or disease of the central somatosensory nervous system, is a serious consequence of spinal cord injury, stroke, multiple sclerosis, and other conditions affecting the central nervous system. A collaborative effort between the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks public-private partnership and the American Pain Society, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks-American Pain Society Pain Taxonomy (AAPT) initiative, invited a working group to develop diagnostic criteria for central neuropathic pain. The criteria for central neuropathic pain that were developed expand upon existing criteria for neuropathic pain and the International Classification of Diseases 11th Revision draft criteria to ensure consistency. This article focuses on central neuropathic pain associated with spinal cord injury, stroke, and multiple sclerosis, but the AAPT framework can be extended to central pain due to other causes such as traumatic brain injury. The classification of central neuropathic pain is organized according to the AAPT multidimensional framework, specifically: 1) core diagnostic criteria, 2) common features, 3) common medical and psychiatric comorbidities, 4) neurobiological, psychosocial, and functional consequences, and 5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors.Perspective: The AAPT chronic central neuropathic pain taxonomy provides a classification for central pain associated with spinal cord injury, stroke, and multiple sclerosis. The diagnostic criteria are organized according to the AAPT multidimensional framework, specifically: 1) core diagnostic criteria, 2) common features, 3) common medical and psychiatric comorbidities, 4) neurobiological, psychosocial, and functional consequences, and 5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors. [ABSTRACT FROM AUTHOR]

Objective. Potential peripheral sources of pain from subcutaneous tissue can require invasive evocative tests for their localization and assessment. Here, we describe studies whose ultimate goal is development of a noninvasive evocative test for subcutaneous, painful tissue. Design. We used a rat model of a focal and subcutaneous neuroma to test the hypothesis that intense focused ultrasound can differentiate focal and subcutaneous neuropathic tissue from control tissue. To do so, we first applied intense focused ultrasound (2 MHz, with individual pulses of 0.1 second in duration) to the rat's neuroma while the rat was under light anesthesia. We started with low values of intensity, which we increased until intense focused ultrasound stimulation caused the rat to reliably flick its paw. We then applied that same intense focused ultrasound protocol to control tissue away from the neuroma and assayed for the rat's response to that stimulation. Results. Intense focused ultrasound of sufficient strength (ISATA of 600 +/− 160 W/cm2) applied to the neuroma caused the rat to flick its paw, while the same intense focused ultrasound applied millimeters to a centimeter away failed to induce a paw flick. Conclusion. Successful stimulation of the neuroma by intense focused ultrasound required colocalization of the neuroma and intense focused ultrasound supporting our hypothesis. [ABSTRACT FROM AUTHOR]

Optimal management of patients with chronic neuropathic pain requires a multidisciplinary approach that may include surgery. Yet despite the fact that lumbosacral spinal surgery, for example, is performed in thousands of patients every year, there is very little controlled clinical data to support its use or that of other surgical techniques in the treatment of chronic nonmalignant pain, especially neuropathic pain. Nevertheless, there is evidence of some success for ablative techniques such as dorsal root entry zone lesioning for phantom limb pain and girdle-zone neuropathic pain, and sympathectomy for the treatment of complex regional pain syndrome, and a variety of operations for tic douloureux. However, before considering a surgical procedure, a nonsurgical approach should have been tried and the suitability of the patient must be carefully assessed. To fully establish the role of surgery in the treatment of chronic neuropathic pain, further well-designed, prospective, controlled trials are essential. [ABSTRACT FROM AUTHOR]

Unlabelled: Accurate classification of chronic pain conditions requires reliable and valid pain assessment. Moreover, pain assessment serves several additional functions, including documenting the severity of the pain condition, tracking the longitudinal course of pain, and providing mechanistic information. Thorough pain assessment must address multiple domains of pain, including the sensory and affective qualities of pain, temporal dimensions of pain, and the location and bodily distribution of pain. Where possible, pain assessment should also incorporate methods to identify pathophysiological mechanisms underlying the pain. This article discusses assessment of chronic pain, including approaches available for assessing multiple pain domains and for addressing pathophysiological mechanisms. We conclude with recommendations for optimal pain assessment.Perspective: Pain assessment is a critical prerequisite for accurate pain classification. This article describes important features of pain that should be assessed, and discusses methods that can be used to assess the features and identify pathophysiological mechanisms contributing to pain. [ABSTRACT FROM AUTHOR]

Abstract: Neuropathic pain (NP) is often refractory to pharmacologic and noninterventional treatment. On behalf of the International Association for the Study of Pain Neuropathic Pain Special Interest Group, the authors evaluated systematic reviews, clinical trials, and existing guidelines for the interventional management of NP. Evidence is summarized and presented for neural blockade, spinal cord stimulation (SCS), intrathecal medication, and neurosurgical interventions in patients with the following peripheral and central NP conditions: herpes zoster and postherpetic neuralgia (PHN); painful diabetic and other peripheral neuropathies; spinal cord injury NP; central poststroke pain; radiculopathy and failed back surgery syndrome (FBSS); complex regional pain syndrome (CRPS); and trigeminal neuralgia and neuropathy. Due to the paucity of high-quality clinical trials, no strong recommendations can be made. Four weak recommendations based on the amount and consistency of evidence, including degree of efficacy and safety, are: 1) epidural injections for herpes zoster; 2) steroid injections for radiculopathy; 3) SCS for FBSS; and 4) SCS for CRPS type 1. Based on the available data, we recommend not to use sympathetic blocks for PHN nor radiofrequency lesions for radiculopathy. No other conclusive recommendations can be made due to the poor quality of available data. Whenever possible, these interventions should either be part of randomized clinical trials or documented in pain registries. Priorities for future research include randomized clinical trials, long-term studies, and head-to-head comparisons among different interventional and noninterventional treatments. [Copyright &y& Elsevier]

Abstract: Patients with neuropathic pain (NP) are challenging to manage and evidence-based clinical recommendations for pharmacologic management are needed. Systematic literature reviews, randomized clinical trials, and existing guidelines were evaluated at a consensus meeting. Medications were considered for recommendation if their efficacy was supported by at least one methodologically-sound, randomized clinical trial (RCT) demonstrating superiority to placebo or a relevant comparison treatment. Recommendations were based on the amount and consistency of evidence, degree of efficacy, safety, and clinical experience of the authors. Available RCTs typically evaluated chronic NP of moderate to severe intensity. Recommended first-line treatments include certain antidepressants (i.e., tricyclic antidepressants and dual reuptake inhibitors of both serotonin and norepinephrine), calcium channel α2-δ ligands (i.e., gabapentin and pregabalin), and topical lidocaine. Opioid analgesics and tramadol are recommended as generally second-line treatments that can be considered for first-line use in select clinical circumstances. Other medications that would generally be used as third-line treatments but that could also be used as second-line treatments in some circumstances include certain antiepileptic and antidepressant medications, mexiletine, N-methyl-d-aspartate receptor antagonists, and topical capsaicin. Medication selection should be individualized, considering side effects, potential beneficial or deleterious effects on comorbidities, and whether prompt onset of pain relief is necessary. To date, no medications have demonstrated efficacy in lumbosacral radiculopathy, which is probably the most common type of NP. Long-term studies, head-to-head comparisons between medications, studies involving combinations of medications, and RCTs examining treatment of central NP are lacking and should be a priority for future research. [Copyright &y& Elsevier]