Medical cannabis treatment for chronic pain: Outcomes and prediction of response.

BACKGROUND: Although studied in a few randomized controlled trials, the efficacy of medical cannabis (MC) for chronic pain remains controversial. Using an alternative approach, this multicentre, questionnaire-based prospective cohort was aimed to assess the long-term effects of MC on chronic pain of various aetiologies and to identify predictors for MC treatment success. METHODS: Patients with chronic pain, licensed to use MC in Israel, reported weekly average pain intensity (primary outcome) and related symptoms before and at 1, 3, 6, 9 and 12 months following MC treatment initiation. A general linear model was used to assess outcomes and identify predictors for treatment success (≥30% reduction in pain intensity). RESULTS: A total of 1,045 patients completed the baseline questionnaires and initiated MC treatment, and 551 completed the 12-month follow-up. At 1 year, average pain intensity declined from baseline by 20% [-1.97 points (95%CI = -2.13 to -1.81; p < 0.001)]. All other parameters improved by 10%-30% (p < 0.001). A significant decrease of 42% [reduction of 27 mg; (95%CI = -34.89 to 18.56, p < 0.001)] from baseline in morphine equivalent daily dosage of opioids was also observed. Reported adverse effects were common but mostly non-serious. Presence of normal to long sleep duration, lower body mass index and lower depression score predicted relatively higher treatment success, whereas presence of neuropathic pain predicted the opposite. CONCLUSIONS: This prospective study provides further evidence for the effects of MC on chronic pain and related symptoms, demonstrating an overall mild-to-modest long-term improvement of the tested measures and identifying possible predictors for treatment success.

[THE MISTAKE OF CUT AND PASTE FROM ACUTE PAIN TO CHRONIC PAIN].

INTRODUCTION: What is a physician to do when the tools in his toolbox fail him? In the field of chronic pain, we are told that imaging studies are often so non-specific as to barely distinguish between symptomatic and asymptomatic individuals. "Advanced pain management techniques and off-label use of popular pain medicines do not withstand the rigors of controlled clinical trials and in many cases have been shown to be harmful. We are informed by the CDC that we are in the midst of a deadly "physician-driven" epidemic of prescribed opioid use disorder. The British Medical Society refers to "our silent addicts" explaining that pregabalin is the "new valium". The manufacturers of oxycodone, pregabalin and duloxetine have been successfully sued for up to $650 million for having overstated the benefits and understated the risks of their products. There has been a huge accumulation of scientific literature over 30 years demonstrating that pain-related beliefs, attitudes and behaviors are the most powerful predictors of outcome: more so than depression, anxiety, PTSD or personality type. All this confusion begs for a change of approach and treatment platform. This article wishes to introduce the reader to a different set of safer, more evidence-based tools to consider when faced with a problematic chronic pain patient.

Peripheral nervous system origin of phantom limb pain.

Nearly all amputees continue to feel their missing limb as if it still existed, and many experience chronic phantom limb pain (PLP). What is the origin of these sensations? There is currently a broad consensus among investigators that PLP is a top-down phenomenon, triggered by loss of sensory input and caused by maladaptive cortical plasticity. We tested the alternative hypothesis that PLP is primarily a bottom-up process, due not to the loss of input but rather to exaggerated input, generated ectopically in axotomized primary afferent neurons in the dorsal root ganglia (DRGs) that used to innervate the limb. In 31 amputees, the local anesthetic lidocaine was applied intrathecally and/or to the DRG surface (intraforaminal epidural block). This rapidly and reversibly extinguished PLP and also nonpainful phantom limb sensation (npPLS). Control injections were ineffective. For intraforaminal block, the effect was topographically appropriate. The suppression of PLP and npPLS could also be demonstrated using dilute lidocaine concentrations that are sufficient to suppress DRG ectopia but not to block the propagation of impulses generated further distally in the nerve. PLP is driven primarily by activity generated within the DRG. We recommend the DRG as a target for treatment of PLP and perhaps also other types of regional neuropathic pain.

Hypnotic relaxation vs amitriptyline for tension-type headache: let the patient choose.

BACKGROUND: Although both pharmacological and behavioral interventions may relieve tension-type headache, data are lacking regarding treatment preference, long-term patient compliance, and feasibility of behavioral intervention in a standard neurological outpatient clinic setting. OBJECTIVE: To describe patient choice, long-term compliance, and clinical outcome in a neurological clinic setting where patients are given the choice of the approach they wish to pursue. DESIGN: Patients presenting to the headache clinic with a diagnosis of tension-type headache that justified prophylactic therapy (frequent episodic tension-type headache or chronic tension-type headache) were given the choice of amitriptyline (AMT) treatment or hypnotic relaxation (HR), and were treated accordingly. Patients were given the option to cross-over to the other treatment group at each visit. HR was performed during standard length neurology clinic appointments by a neurologist trained to perform hypnosis (Y.E.). Follow-up interviews were performed between 6 and 12 months following treatment initiation to evaluate patient compliance, changes in headache frequency or severity, and quality-of-life parameters. RESULTS: Ninety-eight patients were enrolled, 92 agreed to receive prophylactic therapy of some kind. Fifty-three (57.6%) patients chose HR of which 36 (67.9%) actually initiated this treatment, while 39 (42.4%) chose pharmacological therapy with AMT of which 25 (64.1%) patients actually initiated therapy. Patients with greater analgesic use were more likely to opt for AMT (P= .0002). Eleven of the patients initially choosing AMT and 2 of the patients initially choosing HR crossed over to the other group. Seventy-four percent of the patients in the HR group and 58% of patients in the AMT group had a 50% reduction in the frequency of headaches (P= .16). Long-term adherence to treatment with HR exceeded that of AMT. At the end of the study period, 26 of 47 patients who tried HR compared with 10 of 27 who tried AMT continued receiving their initial treatment. CONCLUSIONS: HR treatment was a more popular choice among patients. Patients choosing HR reported greater symptom relief than those choosing AMT and were found to have greater treatment compliance. Patients receiving HR were less likely to change treatments. HR practiced by a neurologist is feasible in a standard neurological outpatient clinic setting; HR training should be considered for neurologists involved in headache treatment.