Fluoroscopy-Guided High-Intensity Focused Ultrasound Neurotomy of the Lumbar Zygapophyseal Joints: A Clinical Pilot Study.

OBJECTIVE: To investigate the safety and feasibility of a fluoroscopy-guided, high-intensity focused ultrasound system for zygapophyseal joint denervation as a treatment for chronic low back pain. METHODS: The clinical pilot study was performed on 10 participants diagnosed with lumbar zygapophyseal joint syndrome. Each participant had a documented positive response to a diagnostic block or a previous, clinically beneficial radiofrequency ablation. For a descriptive study, the primary outcome was the safety question. All device- or procedure-related adverse events were collected. Secondary outcome variables included the average numeric rating scale for pain, the Roland-Morris Disability Questionnaire, the Brief Pain Inventory, the Patient Global Impression of Change, the morphine equivalent dose, and the finding of the neurological examination. RESULTS: All participants tolerated the procedure well with no significant device- or procedure-related adverse events; there was one episode of transient pain during the procedure. The average numeric rating scale score for pain decreased from 6.2 at baseline to 2.1 (n = 10) after 1 month, 4.9 (n = 9) after 3 months, 3.0 (n = 8) after 6 months, and 3.0 (n = 6) after 12 months. The ratio of participants who were considered a treatment success was 90% at 1 month, 50% at 3 months, 60% at 6 months, and 40% at 12 months. CONCLUSIONS: The first clinical pilot study using a noninvasive, fluoroscopy-guided, high-intensity focused ultrasound lumbar zygapophyseal neurotomy resulted in no significant device- or procedure-related adverse events and achieved clinical success comparable with that of routine radiofrequency ablation.

Use of medical cannabis by patients with fibromyalgia in Canada after cannabis legalisation: a cross-sectional study.

OBJECTIVES: Medications have only small to moderate effects on symptoms in fibromyalgia (FM). Cannabinoids, including medical cannabis (MC) may have potential to fill this gap. Since recreational legalisation of cannabis in Canada, patients have easier access and may be self-medicating with cannabis. We have examined the prevalence and characteristics of MC use in FM patients. METHODS: During a two-month period (June-August 2019), consecutive attending rheumatology patients participated in an onsite survey comprising 2 questionnaires: 1) demographic and disease information completed by the rheumatologist, 2) patient anonymous questionnaire of health status, cannabis use (recreational and/or medicinal) and characteristics of use. RESULTS: In a cohort of 1000 rheumatology attendees, 117 (11.7%) were diagnosed with FM. Ever use of MC was reported by 28 (23.9%; 95%CI: 16.5%-32.7%) FM patients compared to 98 (11.1%; 95%CI: 9.1%-13.4%) non-FM patients. Among FM ever users, 17 (61%) patients continued use of MC. FM ever users vs. FM nonusers tended to be younger, 53 vs. 58 years (p=0.072), were more likely unemployed or disabled 39% vs. 17% (p=0.019) and used more medication types (p=0.013) but did not differ in symptom severity parameters. Cigarette smoking and recreational cannabis were more common in ever users. Global symptom relief on a VAS (1-10) was 7.0±2.3. CONCLUSIONS: FM patients have commonly used MC, with more than half continuing use. Reported symptom relief was substantial. Cigarette smoking and recreational cannabis use may play a facilitatory role in MC use in FM. Adjunctive MC may be a treatment consideration for some FM patients.

Partial recovery of abnormal insula and dorsolateral prefrontal connectivity to cognitive networks in chronic low back pain after treatment.

We previously reported that effective treatment of chronic low back pain (CLBP) reversed abnormal brain structure and functional MRI (fMRI) activity during cognitive task performance, particularly in the left dorsolateral prefrontal cortex (DLPFC). Here, we used resting-state fMRI to examine how chronic pain affects connectivity of brain networks supporting cognitive functioning and the effect of treatment in 14 CLBP patients and 16 healthy, pain-free controls (scans were acquired at baseline for all subjects and at 6-months post-treatment for patients and a matched time-point for 10 controls). The main networks activated during cognitive task performance, task-positive network (TPN) and task-negative network (TNN) (aka default mode) network, were identified in subjects' task fMRI data and used to define matching networks in resting-state data. The connectivity of these cognitive resting-state networks was compared between groups, and before and after treatment. Our findings converged on the bilateral insula (INS) as the region of aberrant cognitive resting-state connectivity in patients pretreatment versus controls. These findings were complemented by an independent, data-driven approach showing altered global connectivity of the INS. Detailed investigation of the INS confirmed reduced connectivity to widespread TPN and TNN areas, which was partially restored post-treatment. Furthermore, analysis of diffusion-tensor imaging (DTI) data revealed structural changes in white matter supporting these findings. The left DLPFC also showed aberrant connectivity that was restored post-treatment. Altogether, our findings implicate the bilateral INS and left DLPFC as key nodes of disrupted cognition-related intrinsic connectivity in CLBP, and the resulting imbalance between TPN and TNN function is partially restored with treatment.

Rates and Correlates of Unemployment Across Four Common Chronic Pain Diagnostic Categories.

PURPOSE: To examine rates and correlates of unemployment across distinct common chronic pain diagnoses. METHODS: Data were analyzed from a sample of 2,382 patients with chronic pain in the Quebec Pain Registry (QPR). Patients were grouped into the following diagnostic categories based on their primary pain diagnosis recorded in the QPR: musculoskeletal pain; myofascial pain; neuropathic pain, and visceral pain. Analyses were performed to examine the associations between pain diagnosis, patient demographics, pain intensity, depressive symptoms, and unemployment status. RESULTS: Pain diagnosis, age, marital status, education, pain intensity, and depressive symptoms were each significant unique predictors of unemployment status in a hierarchical logistic regression analysis; the addition of depressive symptoms in this model contributed to the greatest increment of model fit. CONCLUSIONS: Depressive symptoms are associated with unemployment across a number of common chronic pain conditions, even when controlling for other factors that are associated with unemployment in these patients. Depressive symptoms, as a modifiable factor, may thus be an important target of intervention for unemployed patients with chronic pain.

Specific and number of comorbidities are associated with increased levels of temporomandibular pain intensity and duration.

BACKGROUND: Temporomandibular pain disorder (TMD) is a common pain condition in the face. People with TMD report multiple pain comorbidities. The presence of fibromyalgia and migraine in people with TMD is associated with an increase in TMD pain intensity and duration. However, data on the relationship between increasing number of pain comorbidities and TMD pain are rare. The aims of this study were: firstly to evaluate the extent to which increasing number of comorbidities is associated with increasing TMD pain intensity and duration; and secondly to evaluate the extent to which the presence of specific comorbidities is associated with increasing TMD pain intensity and duration. METHODS: The sample included 180 people seeking TMD treatment at Boston and Montreal clinics. TMD was diagnosed using the Research Diagnostic Criteria for TMD. A Numerical Pain Rating Scale assessed TMD pain intensity and participants provided their TMD pain duration in a study questionnaire. The comorbidities of migraine, chronic fatigue syndrome, irritable bowel syndrome, interstitial cystitis and restless leg syndrome were diagnosed by 5 validated diagnostic questionnaires. The associations were analyzed by linear regression, controlling for confounders. RESULTS: There was a positive association between the number of comorbidities present and TMD pain intensity (p < 0.01) and between the number of comorbidities present and TMD pain duration (p < 0.01). Also, the presence of migraine was positively associated with TMD pain intensity (p < 0.01) and the presence of chronic fatigue syndrome was positively associated with TMD pain intensity (p < 0.05) and with TMD pain duration (p < 0.01). When TMD patients were separated into groups, these associations did not change for the myofascial pain group, whereas in the non-myofascial pain group, the relationship between number of comorbidities and TMD pain duration was the only one still present. CONCLUSION: This study shows that the number of comorbidities is positively associated with TMD pain duration and intensity. The presence of specific conditions, such as migraine and chronic fatigue syndrome, is associated with an increase in TMD intensity and duration.

Rheumatologists lack confidence in their knowledge of cannabinoids pertaining to the management of rheumatic complaints.

BACKGROUND: Arthritis pain is reported as one of the most common reasons for persons using medical herbal cannabis in North America. "Severe arthritis" is the condition justifying legal use of cannabis in over half of all authorizations in Canada, where cannabis remains a controlled substance. As champions for the care of persons with arthritis, rheumatologists must be knowledgeable of treatment modalities both traditional and non-traditional, used by their patients. As study of cannabinoid molecules in medicine is recent, we have examined the confidence in the knowledge of cannabinoids expressed by Canadian rheumatologists. METHODS: The confidence of rheumatologists in their knowledge of cannabinoid molecules and mechanisms relevant to rheumatology, and their ability to advise patients about cannabinoid treatments was recorded by an online questionnaire circulated via email to the entire Canadian Rheumatology Association membership. RESULTS: Over three quarters of the 128 respondents lacked confidence in their knowledge of cannabinoid molecules. While 45% of respondents believed there was no current role for cannabinoids in rheumatology patient care, only 25% supported any use of herbal cannabis. With 70% never having previously prescribed or recommended any cannabinoid treatment, uncertainty regarding good prescribing practices was prevalent. Concerns about risks of cannabis use were in line with the current literature. CONCLUSIONS: Rheumatologists lacked confidence in their knowledge of cannabinoid molecules in general and in their competence to prescribe any cannabinoid for rheumatic complaints. In line with this uncertainty, there is reticence to prescribe cannabinoid preparations for rheumatology patients. Guidance is required to inform rheumatologists on the evidence regarding cannabinoids.

Altered serum bile acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity.

ABSTRACT: Alterations in the composition and function of the gut microbiome in women with fibromyalgia have recently been demonstrated, including changes in the relative abundance of certain bile acid-metabolizing bacteria. Bile acids can affect multiple physiological processes, including visceral pain, but have yet to be explored for association to the fibromyalgia gut microbiome. In this study, 16S rRNA sequencing and targeted metabolomic approaches were used to characterize the gut microbiome and circulating bile acids in a cohort of 42 women with fibromyalgia and 42 healthy controls. Alterations in the relative abundance of several bacterial species known to metabolize bile acids were observed in women with fibromyalgia, accompanied by significant alterations in the serum concentration of secondary bile acids, including a marked depletion of α-muricholic acid. Statistical learning algorithms could accurately detect individuals with fibromyalgia using the concentration of these serum bile acids. Serum α-muricholic acid was highly correlated with symptom severity, including pain intensity and fatigue. Taken together, these findings suggest serum bile acid alterations are implicated in nociplastic pain. The changes observed in the composition of the gut microbiota and the concentration of circulating secondary bile acids seem congruent with the phenotype of increased nociception and are quantitatively correlated with symptom severity. This is a first demonstration of circulating bile acid alteration in individuals with fibromyalgia, potentially secondary to upstream gut microbiome alterations. If corroborated in independent studies, these observations may allow for the development of molecular diagnostic aids for fibromyalgia as well as mechanistic insights into the syndrome.

Predictors of Pain Reduction Among Fibromyalgia Patients Using Medical Cannabis: A Long-Term Prospective Cohort Study.

OBJECTIVE: Many patients with fibromyalgia (FM) report using cannabis as a strategy to improve pain. Given that pain often co-occurs with symptoms of anxiety and depression (i.e., negative affect) and sleep problems among patients with FM, improvements in these symptoms might indirectly contribute to reductions in pain intensity following cannabis use. The main objective of the study was to examine whether changes in pain intensity following initiation of medical cannabis among patients with FM could be attributed to concurrent changes (i.e., reductions) in negative affect and sleep problems. METHODS: This was a 12-month prospective cohort study among patients with FM (n = 323) initiating medical cannabis under the care of physicians. Patients were assessed at baseline, and follow-up assessment visits occurred every 3 months after initiation of medical cannabis. Patients' levels of pain intensity, negative affect, and sleep problems were assessed across all visits. RESULTS: Multilevel mediation analyses indicated that reductions in patients' levels of pain intensity were partly explained by concurrent reductions in sleep problems and negative affect (both P < 0.001). This remained significant even when accounting for patients' baseline characteristics or changes in medical cannabis directives over time (all P > 0.05). CONCLUSION: Our findings provide preliminary insight into the potential mechanisms of action underlying pain reductions among patients with FM who are using medical cannabis. Given the high attrition rate (i.e., 75%) observed in the present study at 12 months, our findings cannot be generalized to all patients with FM who are using medical cannabis.

Effective treatment of chronic low back pain in humans reverses abnormal brain anatomy and function.

Chronic pain is associated with reduced brain gray matter and impaired cognitive ability. In this longitudinal study, we assessed whether neuroanatomical and functional abnormalities were reversible and dependent on treatment outcomes. We acquired MRI scans from chronic low back pain (CLBP) patients before (n = 18) and 6 months after (spine surgery or facet joint injections; n = 14) treatment. In addition, we scanned 16 healthy controls, 10 of which returned 6 months after the first visit. We performed cortical thickness analysis on structural MRI scans, and subjects performed a cognitive task during the functional MRI. We compared patients and controls, as well as patients before versus after treatment. After treatment, patients had increased cortical thickness in the left dorsolateral prefrontal cortex (DLPFC), which was thinner before treatment compared with controls. Increased DLPFC thickness correlated with the reduction of both pain and physical disability. Additionally, increased thickness in primary motor cortex was associated specifically with reduced physical disability, and right anterior insula was associated specifically with reduced pain. Left DLPFC activity during an attention-demanding cognitive task was abnormal before treatment, but normalized following treatment. These data indicate that functional and structural brain abnormalities-specifically in the left DLPFC-are reversible, suggesting that treating chronic pain can restore normal brain function in humans.

The 2010 American college of rheumatology fibromyalgia survey diagnostic criteria and symptom severity scale is a valid and reliable tool in a French speaking fibromyalgia cohort.

BACKGROUND: Fibromyalgia (FM) is a pain condition with associated symptoms contributing to distress. The Fibromyalgia Survey Diagnostic Criteria and Severity Scale (FSDC) is a patient-administered questionnaire assessing diagnosis and symptom severity. Locations of body pain measured by the Widespread Pain Index (WPI), and the Symptom Severity scale (SS) measuring fatigue, unrefreshing sleep, cognitive and somatic complaints provide a score (0-31), measuring a composite of polysymptomatic distress. The reliability and validity of the translated French version of the FSDC was evaluated. METHODS: The French FSDC was administered twice to 73 FM patients, and was correlated with measures of symptom status including: Fibromyalgia Impact Questionnaire (FIQ), Health Assessment Questionnaire (HAQ), McGill Pain Questionnaire (MPQ), and a visual analogue scale (VAS) for global severity and pain. Test-retest reliability, internal consistency, and construct validity were evaluated. RESULTS: Test-retest reliability was between .600 and .888 for the 25 single items of the FSDC, and .912 for the total FSDC, with all correlations significant (p < 0.0001). There was good internal consistency measured by Cronbach's alpha (.846 for FSDC assessment 1, and .867 for FSDC assessment 2). Construct validity showed significant correlations between the FSDC and FIQ 0.670, HAQ 0.413, MPQ 0.562, global VAS 0.591, and pain VAS 0.663 (all p<0.001). CONCLUSIONS: The French FSDC is a valid instrument in French FM patients with reliability and construct validity. It is easily completed, simple to score, and has the potential to become the standard for measurement of polysymptomatic distress in FM.

Transitional Pain Care in Quebec: Did We Forget Our Youths? A Brief Research Report.

Adolescents and young adults (AYAs) represent a unique population with distinct psycho-social risks and care needs. About 10% of AYAs live with chronic pain (CP) and transition to adult pain care between 16 and 25 years of age. These transitions in care happen simultaneously with other bio-psycho-social changes and require flexible multi-disciplinary support models. As it stands, transitional pain care appears suboptimal, fragmented, and opportunistic in Quebec (Canada). The objective of this Brief Report is, therefore, to present our study findings and propose a multi-disciplinary transitional framework vision applicable to AYAs living with CP. Data were collected using a sequential-consensual qualitative design with a longitudinal participatory component. The consecutive stages of this work included an exploratory stage, semi-structured interviews with primary care providers, and inter-disciplinary deliberative stakeholder consultation groups. The deductive inductive thematic approach and the three-level Health Care Transition Research Consortium's theoretical framework were used to analyze the data. A representative group of stakeholders discussed findings from the first two steps, made fifteen actionable recommendations and formulated their vision of a transitional pain care model that can be further adapted in other settings. The study results present important insights into various psycho-social factors associated with transitional pain care for AYAs.

Dietary Intake Is Unlikely to Explain Symptom Severity and Syndrome-Specific Microbiome Alterations in a Cohort of Women with Fibromyalgia.

BACKGROUND: Significant alterations were recently identified in the composition and putative function of the gut microbiome in women with fibromyalgia. As diet can influence the composition of the gut microbiome, differences in nutritional intake could, in theory, account for some of these specific fibromyalgia microbiome alterations. The current study aims to compare the diet of women with fibromyalgia to that of controls in order to explore possible associations between the intake of certain nutrients, symptom severity and gut microbiome composition. METHODS: The study population was comprised of 56 women with fibromyalgia and 68 controls. Dietary intake was assessed using the NIH Automated Self-Administered 24 h recall, following dietitian's instructions and the completion of a three-day dietary recall. The gut microbiome was assessed by 16S ribosomal RNA gene sequencing of stool samples. RESULTS: Most demographic and anthropometric characteristics were comparable between groups. The average energy and macronutrient intake (total and relative) and overall diet quality score were not different between patients and controls, nor were the main vitamins, minerals, fatty acids, alcohol, caffeine, sugar or fiber intakes. The daily intake of micronutrients and normalized macronutrients in women with fibromyalgia was largely not correlated with disease-specific measures, including pain intensity, fatigue, cognitive symptoms and quality of sleep, or with the relative quantity of almost any of the gut microbiome bacterial taxa differentially abundant in fibromyalgia. CONCLUSION: These data demonstrate that dietary intakes, as evaluated by self-reported questionnaires, probably cannot explain the syndrome-specific differences in gut microbiome or the clinical phenotype of fibromyalgia.

The effect of a topical combination of clonidine and pentoxifylline on post-traumatic neuropathic pain patients: study protocol for a randomized, double-blind placebo-controlled trial.

BACKGROUND: First-line pharmacotherapy for neuropathic pain entails the use of systemic antidepressants and anticonvulsants. These drugs are not optimally effective and poorly tolerated, especially for older patients with comorbid conditions. Given the high number of such patients, there is a need for a greater repertoire of safer and more effective analgesics. Clonidine and pentoxifylline are vasodilator agents that work synergistically to enhance tissue perfusion and oxygenation. The topical administration of these drugs, individually and in combination, has shown anti-nociceptive properties in rodent models of neuropathic pain. A topically-administered combination of clonidine and pentoxifylline also effectively reduced the intensity of both spontaneous and evoked pain in healthy volunteers with experimentally-induced neuropathic pain. The next step in advancing this formulation to clinical use is the undertaking of a phase II clinical study to assess its efficacy and safety in neuropathic pain patients. METHODS/DESIGN: This is a study protocol for a randomized, double-blind, placebo-controlled, phase II clinical trial with a cross-over design. It is a single-centered, 5-week study that will enroll a total of 32 patients with post-traumatic peripheral neuropathic pain. Patients will be treated topically with either a combination of clonidine and pentoxifylline or placebo for a period of 2 weeks each, in randomly assigned order across patients, with an intervening washout period of 1 week. The primary outcome measures of the study are the intensity of spontaneous pain recorded daily in a pain diary with a visual analog scale, and the degree of mechanical allodynia evoked by a brush stimulus. The secondary outcome measures of the study include scores of pain relief and change in the area of punctate hyperalgesia. This trial has been prospectively registered with ClinicalTrials.gov on November 1, 2017. ClinicalTrials.gov Identifier: NCT03342950 . DISCUSSION: The analgesic use of topical treatment with clonidine and pentoxifylline in combination has not been investigated in post-traumatic neuropathic pain. This study could generate the first evidence for the efficacy and safety of the formulation in alleviating pain in patients with neuropathic pain. Furthermore, this trial will provide objective grounds for the investigation of other agents that enhance tissue oxygenation in the topical treatment of peripheral neuropathic pain. TRIAL REGISTRATION: This trial has been registered with ClinicalTrials.gov owned by NIH's US National Library of Medicine. ClinicalTrials.gov NCT03342950 . Registered on November 1, 2017 (trial was prospectively registered). PROTOCOL VERSION AND IDENTIFIERS: This is protocol version 5, dated June 2018. McGill University Health Center (MUHC) Reaseach Ethics Board (REB) identification number: TTNP 2018-3906.

Epigenetic signature of chronic low back pain in human T cells.

OBJECTIVE: Determine if chronic low back pain (LBP) is associated with DNA methylation signatures in human T cells that will reveal novel mechanisms and potential therapeutic targets and explore the feasibility of epigenetic diagnostic markers for pain-related pathophysiology. METHODS: Genome-wide DNA methylation analysis of 850,000 CpG sites in women and men with chronic LBP and pain-free controls was performed. T cells were isolated (discovery cohort, n = 32) and used to identify differentially methylated CpG sites, and gene ontologies and molecular pathways were identified. A polygenic DNA methylation score for LBP was generated in both women and men. Validation was performed in an independent cohort (validation cohort, n = 63) of chronic LBP and healthy controls. RESULTS: Analysis with the discovery cohort revealed a total of 2,496 and 419 differentially methylated CpGs in women and men, respectively. In women, most of these sites were hypomethylated and enriched in genes with functions in the extracellular matrix, in the immune system (ie, cytokines), or in epigenetic processes. In men, a unique chronic LBP DNA methylation signature was identified characterized by significant enrichment for genes from the major histocompatibility complex. Sex-specific polygenic DNA methylation scores were generated to estimate the pain status of each individual and confirmed in the validation cohort using pyrosequencing. CONCLUSION: This study reveals sex-specific DNA methylation signatures in human T cells that discriminates chronic LBP participants from healthy controls.

Day-to-day opioid withdrawal symptoms, psychological distress, and opioid craving in patients with chronic pain prescribed opioid therapy.

BACKGROUND: Research has shown that opioid craving is one of the strongest determinants of opioid misuse in patients with chronic pain. To date, however, little is known on the factors that contribute to opioid craving in these patients. It is possible that patients' physical dependence to opioids, manifested by opioid withdrawal symptoms in between daily opioid doses, contribute to opioid craving. Physical dependence symptoms might also lead to psychological distress, which in turn might contribute to opioid craving. The first objective of this study was to examine the day-to-day association between opioid withdrawal symptoms and opioid craving among patients with chronic pain. We also examined whether negative affect and catastrophic thinking mediated this association. METHODS: In this longitudinal study, chronic pain patients (n = 79) prescribed short-acting opioids completed daily diaries for 14 consecutive days. Diaries assessed a host of pain, psychological, and opioid-related variables. RESULTS: Day-to-day elevations in opioid withdrawal symptoms were associated with heightened opioid craving (p < .001). Results of a multilevel mediation analysis revealed that this association was mediated by patients' daily levels of negative affect and catastrophizing (p < .001). CONCLUSIONS: Our study provides valuable new insights into our understanding of factors that may contribute to prescription opioid craving among patients with chronic pain.

Day-to-day hedonic and calming effects of opioids, opioid craving, and opioid misuse among patients with chronic pain prescribed long-term opioid therapy.

ABSTRACT: Concerns have been raised regarding the misuse of opioids among patients with chronic pain. Although a number of factors may contribute to opioid misuse, research has yet to examine if the hedonic and calming effects that can potentially accompany the use of opioids contribute to opioid misuse. The first objective of this study was to examine the degree to which the hedonic and calming effects of opioids contribute to opioid misuse in patients with chronic pain. We also examined whether the hedonic and calming effects of opioids contribute to patients' daily levels of opioid craving, and whether these associations were moderated by patients' daily levels of pain intensity, catastrophizing, negative affect, or positive affect. In this longitudinal diary study, patients (n = 103) prescribed opioid therapy completed daily diaries for 14 consecutive days. Diaries assessed a host of pain, psychological, and opioid-related variables. The hedonic and calming effects of opioids were not significantly associated with any type of opioid misuse behavior. However, greater hedonic and calming effects were associated with heightened reports of opioid craving (both P's < 0.005). Analyses revealed that these associations were moderated by patients' daily levels of pain intensity, catastrophizing, and negative affect (all P's < 0.001). Results from this study provide valuable new insights into our understanding of factors that may contribute to opioid craving among patients with chronic pain who are prescribed long-term opioid therapy. The implications of our findings for the management of patients with chronic pain are discussed.

Tolerability and Feasibility of X-ray Guided Non-Invasive Ablation of the Medial Branch Nerve with Focused Ultrasound: Preliminary Proof of Concept in a Pre-clinical Model.

Four to six million patients a year in the United States suffer from chronic pain caused by facet joint degeneration. Thermal ablation of the affected facet joint's sensory nerve using radiofrequency electrodes is the therapeutic standard of care. High-intensity focused ultrasound (HIFU) is a novel technology enabling image-guided non-invasive thermal ablation of tissue. Six pigs underwent fluoroscopy-guided HIFU of the medial branch nerve and were followed up for 1 wk (two pigs), 1 mo (two pigs) and 3 mo (two pigs). At the end of each follow-up period, the animals were sacrificed, and targeted tissue was excised and evaluated with computed tomography scans as well as by macro- and micropathology. No significant adverse events were recorded during the procedure or follow-up period. All targets were successfully ablated. X-Ray-guided HIFU is a feasible and promising alternative to radiofrequency ablation of the lumbar facet joint sensory nerve.

The effects of nabilone on sleep in fibromyalgia: results of a randomized controlled trial.

BACKGROUND: Sleep disorders affect many patients with chronic pain conditions. Cannabis has been reported by several patient populations to help sleep. We evaluated the safety and efficacy of nabilone, a synthetic cannabinoid, on sleep disturbance in fibromyalgia (FM), a disease characterized by widespread chronic pain and insomnia. METHODS: We conducted a randomized, double-blind, active-control, equivalency crossover trial to compare nabilone (0.5-1.0 mg before bedtime) to amitriptyline (10-20 mg before bedtime) in patients with FM with chronic insomnia. Subjects received each drug for 2 wk with a 2-wk washout period. The primary outcome was sleep quality, measured by the Insomnia Severity Index and the Leeds Sleep Evaluation Questionnaire. Secondary outcomes included pain, mood, quality of life, and adverse events (AEs). RESULTS: Thirty-one subjects were enrolled and 29 completed the trial (26 women, mean age 49.5 yr). Although sleep was improved by both amitriptyline and nabilone, nabilone was superior to amitriptyline (Insomnia Severity Index difference = 3.2; 95% confidence interval = 1.2-5.3). Nabilone was marginally better on the restfulness (Leeds Sleep Evaluation Questionnaire difference = 0.5 [0.0-1.0]) but not on wakefulness (difference = 0.3 [-0.2 to 0.8]). No effects on pain, mood, or quality of life were observed. AEs were mostly mild to moderate and were more frequent with nabilone. The most common AEs for nabilone were dizziness, nausea, and dry mouth. CONCLUSIONS: Nabilone is effective in improving sleep in patients with FM and is well tolerated. Low-dose nabilone given once daily at bedtime may be considered as an alternative to amitriptyline. Longer trials are needed to determine the duration of effect and to characterize long-term safety.