Melatonin treatment has consistent but transient beneficial effects on sleep measures and pain in patients with severe chronic pain: the DREAM-CP randomised controlled trial

BACKGROUND

Sleep disturbance is a major issue for patients with chronic pain. Melatonin has been shown to improve symptoms of fibromyalgia, but its efficacy in other chronic non-malignant pain conditions is not fully known. Hence, we determined the effect of melatonin in patients with severe noncancer chronic pain.

METHODS

This was a randomised double-blinded crossover trial of modified-release melatonin as Circadin™ compared with placebo. Sixty male and female subjects with chronic severe pain were randomised to receive either 2 mg of Circadin™ or placebo before sleep for 6 weeks, followed by a >4 week washout, then crossing over to the other treatment. Sleep disturbance, quality, and latency were measured using three different validated sleep assessment tools. The primary outcome measure was self-reported sleep disturbance after 6 weeks of treatment. Adverse events were also recorded.

RESULTS

Sleep disturbance after 6 weeks was not significantly altered by melatonin treatment, but differences between melatonin and placebo treatment periods after 3 weeks were seen: sleep disturbance (P=0.014), latency (P=0.04), overall sleep quality (P=0.004), and effect of pain on sleep (P=0.032). Pain intensity scores improved during both treatment periods (both P<0.001). There were no differences in adverse events between treatment periods.

CONCLUSIONS

Circadin™ treatment did not improve sleep disturbance in patients with severe chronic pain compared with placebo at 6 weeks, but there were consistent improvements in aspects of sleep in the shorter term. Given its favourable safety profile, it could be beneficial for some patients with chronic pain.

CLINICAL TRIAL REGISTRATION

ISRCTN12861060.

Supraneural versus Infraneural Approach to transforaMinal Epidural StEroid injection for unilateral lumbosacral radicular pain (SIAMESE): a study protocol for a randomised non-inferiority trial

Background

Lumbosacral radicular pain is commonly treated by transforaminal steroid epidural injection. There are two methods: the supraneural and the infraneural approaches. The supraneural approach can result in rare but catastrophic consequences from injury to the radiculomedullary artery. The infraneural technique avoids the artery; both approaches show efficacy and are used locally.

Methods

This is a protocol for a randomised, single-blinded, non-inferiority trial of infraneural vs supraneural transforaminal epidural injection for lumbosacral radicular pain at a tertiary referral pain management clinic. Adult patients (n=92) with moderate-to-severe lumbosacral radicular pain of >3 months duration, scheduled for transforaminal epidural steroid injection, will be randomised to epidural by either the infraneural or supraneural approach. Only the treating physicians will know which route is used. The primary outcome measure is the differential impact on pain intensity score at 3 months. Secondary outcome measures will include disability and function scores, sleep and activity measures, and adverse events. Participants will be followed up for 12 months.

Conclusions

This study will determine whether the techniques are comparable and, if so, will enable recommendations for the use of an approach without risk of artery damage and catastrophic injury.

Clinical trial registration

ISRCTN 36195887.

Abdominal cutaneous nerve entrapment syndrome: A cross sectional survey of treatment outcomes

Objective

Abdominal Cutaneous Nerve Entrapment Syndrome (ACNES) is a common but under recognised cause of chronic abdominal wall Pain. This survey was carried out to understand the clinical course of the condition following interventions such as nerve blocks and surgical release of entrapped nerve.

Design

Retrospective, Cross-sectional survey.

Setting

Pain Management clinic at University teaching hospital.

Subjects

Adult patients who had interventions either nerve block or surgical release over a 6 year period.

Methods

After written informed consent, participants completed a questionnaire including Brief Pain Inventory (BPI), quality of health measure (EQ-5D-5L), and global impression of change scale as well as open-ended question about the outcomes. Baseline demographics, details of pain condition, interventions received were collected from the health records.

Results

The diagnosis of ACNES was established in 85.2% by ultrasound guided injections. The injection therapy with local anaesthetic and steroid was successful to 75.8% while the surgical release was successful in 90%. The cumulative duration of pain relief varied from 3 weeks to 5 years. A significant difference was noted in BPI (p = 0.001), EQ-5D-5L (p = 0.002) and health thermometer (p = 0.009) post interventions.

Conclusions

Ultrasound guided injections aid the accurate diagnosis of ACNES. Appropriate treatment of ACNES improves both pain control and quality of life.

Sensory mapping of lumbar facet joint pain: a feasibility study

Objective

To evaluate the feasibility of sensory mapping of lumbar facet joint pain in patients scheduled to undergo radiofrequency (RF) denervation.

Design

Prospective cohort study.

Setting

University teaching hospital.

Subjects

A total of 15 participants listed for RF denervation of lumbar facet joint.

Method

After written informed consent, participants were recruited to the study. Participants completed a pain diagram prior to their procedure. After successful image-guided placement of RF cannulas, the sensory detection threshold using 50 Hz stimulation was obtained, followed by application of suprathreshold stimulation. Participants mapped their stimulated area in comparison to their pre-procedure pain diagram.

Results

All 15 participants had previously undergone diagnostic blocks. All participants were able to report either pain or paraesthesia during suprathreshold stimulation. In total, 14 out of 15 participants reported complete coverage of their usual painful area with suprathreshold stimulation of nerves scheduled for RF denervation. In one of the participants, an area of upper lumbar pain was not covered during suprathreshold stimulation. Nearly two-thirds of the participants (n = 9), reported either pain or paraesthesia, outside their normal painful area during suprathreshold stimulation. A total of 71 nerves were scheduled for RF denervation. Sensory electrical stimulation was successfully achieved in 68 out of 71 nerves (96%). The average sensory detection threshold was found to be 0.3 V while the suprathreshold stimulation was 0.6 V.

Conclusion

Lumbar facet joint pain can be mapped using suprathreshold sensory stimulation, which has the potential to introduce objectivity during RF denervation.

Phase II double-blind randomised controlled trial of exogenous administration of melatonin in chronic pain (DREAM-CP): a study protocol

INTRODUCTION

Chronic pain is prevalent, and approximately half of patients with chronic pain experience sleep disturbance. Exogenous melatonin is licensed to treat primary insomnia and there is some evidence for analgesic effects of melatonin.The aim of this study is to investigate the effects of oral melatonin (as Circadin) 2 mg at night in adults with severe non-malignant pain of at least 3 months' duration.

METHODS AND ANALYSIS

We will conduct a randomised double-blind placebo-controlled cross-over study. The primary outcome is sleep disturbance. Secondary outcomes are pain intensity, actigraphy, fatigue, reaction time testing, serum melatonin and endogenous opioid peptide levels along with patient views about study participation.We aim to recruit 60 patients with severe chronic pain (average pain intensity ≥7 on the Brief Pain Inventory (BPI)) from a tertiary referral pain clinic in Northeast Scotland. Participants will be randomised to receive melatonin (as modified release Circadin) 2 mg daily for 6 weeks or placebo, followed by a 4-week washout period, then 6 weeks treatment with the treatment they did not receive. Participants will complete the Verran Snyder-Halpern Sleep Scale, Pittsburgh Sleep Quality Index, Pain and Sleep Questionnaire 3-item index, BPI and psychomotor vigilance reaction time testing at 6 points over 20 weeks. Actigraphy watches will be used to provide objective measures of sleep duration and latency and other sleep measures and will prompt patients to report contemporaneous pain and fatigue scores daily.Cross-over analyses will include tests for effects of treatment, period, treatment-period interaction (carryover effect) and sequence. Within-patient effects and longitudinal data will be analysed using mixed linear models, accounting for potential confounders.

ETHICS AND DISSEMINATION

Approved by Office for Research Ethics Committees Northern Ireland, reference 19/NI/0007. Results will be published in peer-reviewed journals and will be presented at national and international conferences.

TRIAL REGISTRATION NUMBER

ISRCTN12861060.