Evaluating the impact of gabapentinoids on sleep health in patients with chronic neuropathic pain: a systematic review and meta-analysis

Interventions for treating pain and disability in adults with complex regional pain syndrome- an overview of systematic reviews

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic pain condition that usually occurs in a limb following trauma or surgery. It is characterised by persisting pain that is disproportionate in magnitude or duration to the typical course of pain after similar injury. There is currently no consensus regarding the optimal management of CRPS, although a broad range of interventions have been described and are commonly used. This is the first update of the original Cochrane review published in Issue 4, 2013.

OBJECTIVES

To summarise the evidence from Cochrane and non-Cochrane systematic reviews of the efficacy, effectiveness, and safety of any intervention used to reduce pain, disability, or both, in adults with CRPS.

METHODS

We identified Cochrane reviews and non-Cochrane reviews through a systematic search of Ovid MEDLINE, Ovid Embase, Cochrane Database of Systematic Reviews, CINAHL, PEDro, LILACS and Epistemonikos from inception to October 2022, with no language restrictions. We included systematic reviews of randomised controlled trials that included adults (≥18 years) diagnosed with CRPS, using any diagnostic criteria.  Two overview authors independently assessed eligibility, extracted data, and assessed the quality of the reviews and certainty of the evidence using the AMSTAR 2 and GRADE tools respectively. We extracted data for the primary outcomes pain, disability and adverse events, and the secondary outcomes quality of life, emotional well-being, and participants' ratings of satisfaction or improvement with treatment.  MAIN RESULTS: We included six Cochrane and 13 non-Cochrane systematic reviews in the previous version of this overview and five Cochrane and 12 non-Cochrane reviews in the current version. Using the AMSTAR 2 tool, we judged Cochrane reviews to have higher methodological quality than non-Cochrane reviews. The studies in the included reviews were typically small and mostly at high risk of bias or of low methodological quality. We found no high-certainty evidence for any comparison.  There was low-certainty evidence that bisphosphonates may reduce pain intensity post-intervention (standardised mean difference (SMD) -2.6, 95% confidence interval (CI) -1.8 to -3.4, P = 0.001; I2 = 81%; 4 trials, n = 181) and moderate-certainty evidence that they are probably associated with increased adverse events of any nature (risk ratio (RR) 2.10, 95% CI 1.27 to 3.47; number needed to treat for an additional harmful outcome (NNTH) 4.6, 95% CI 2.4 to 168.0; 4 trials, n = 181).  There was moderate-certainty evidence that lidocaine local anaesthetic sympathetic blockade probably does not reduce pain intensity compared with placebo, and low-certainty evidence that it may not reduce pain intensity compared with ultrasound of the stellate ganglion. No effect size was reported for either comparison. There was low-certainty evidence that topical dimethyl sulfoxide may not reduce pain intensity compared with oral N-acetylcysteine, but no effect size was reported. There was low-certainty evidence that continuous bupivacaine brachial plexus block may reduce pain intensity compared with continuous bupivacaine stellate ganglion block, but no effect size was reported. For a wide range of other commonly used interventions, the certainty in the evidence was very low and provides insufficient evidence to either support or refute their use. Comparisons with low- and very low-certainty evidence should be treated with substantial caution. We did not identify any RCT evidence for routinely used pharmacological interventions for CRPS such as tricyclic antidepressants or opioids.

AUTHORS' CONCLUSIONS

Despite a considerable increase in included evidence compared with the previous version of this overview, we identified no high-certainty evidence for the effectiveness of any therapy for CRPS. Until larger, high-quality trials are undertaken, formulating an evidence-based approach to managing CRPS will remain difficult. Current non-Cochrane systematic reviews of interventions for CRPS are of low methodological quality and should not be relied upon to provide an accurate and comprehensive summary of the evidence.

Sleep disorders in chronic pain and its neurochemical mechanisms: a narrative review

Chronic pain (CP) is a prevalent problem, and more than half of patients with CP have sleep disorders. CP comorbidity with sleep disorders imposes immense suffering and seriously affects the patient's quality of life, which is a challenging issue encountered by clinicians. Although the reciprocal interactions between pain and sleep have been studied to some degree, there is still a lack of awareness and comprehensive description of CP comorbidity with sleep disorders. In this narrative review article, we summarize the current knowledge about the present estimates of the prevalence of comorbid sleep disorders in CP patients, sleep detection methods, sleep characterization in CP, and the effect of sleep disorders on CP and current therapies. We also summarize current knowledge of the neurochemical mechanisms of CP comorbidity with sleep disorders. In conclusion, insufficient attention has been paid to the role of sleep disorders in CP patients, and CP patients should be screened for sleep disorders in the clinic. Special attention should be given to a possible risk of drug-drug interaction when using two types of drugs targeting pain and sleep simultaneously. The current insight into the neurobiological mechanisms underlying CP comorbidity with sleep disorders is still rather limited.

Sleep as a Therapeutic Target for Pain Management

PURPOSE OF REVIEW

The purpose of this review is to provide a summary of the utilization of sleep as a therapeutic target for chronic pain and to evaluate the recent literature on current and proposed pharmacologic and non-pharmacologic sleep interventions used in the management of pain disorders.

RECENT FINDINGS

Sleep is a promising therapeutic target in the treatment of pain disorders with both non-pharmacologic and pharmacologic therapies. Non-pharmacologic therapies include cognitive behavioral therapy and sensory-based therapies such as pink noise, audio-visual stimulation, and morning bright light therapy. Pharmacologic therapies include melatonin, z-drugs, gabapentinoids, and the novel orexin antagonists. However, more research is needed to clarify if these therapies can improve pain specifically by improving sleep. There is a vast array of investigational opportunities in sleep-targeted therapies for pathologic pain, and larger controlled, prospective trials are needed to fully elucidate their efficacy.

Integrated Analgesic Care in the Current Human Monkeypox Outbreak: Perspectives on an Integrated and Holistic Approach Combining Old Allies with Innovative Technologies

Monkeypox (MPX) is a zoonotic infection caused by an orthopoxvirus that is endemic to Central and Western Africa. The MPX virus is a part of the same family of viruses as the variola virus, which causes smallpox. Since May 2022, there has been a global increase in the incidence of MPX infections in multiple countries where the illness is not usually prevalent. A growing number of publications have emphasized on the need for increased awareness among all health professionals for the rapid recognition and diagnosis of this disease and for proper public health measures. However, atypical presentations and occurrence of uncommon symptoms receive less than the desired attention. More specifically, MPX infection related nociceptive symptoms are currently underexposed. Nevertheless, reports from the current outbreak have revealed that (severe) pain is one of the major causes for distress and even hospitalization in these patients. As for all serious pain conditions, an integrated, multidisciplinary, and holistic approach is indicated. This approach should be multimodal and include non-pharmacological therapies alongside pharmacological approaches. Health care professionals should be aware of available alternatives when first choice analgesic therapies fail. Protocols for identification of pain type and prolonged monitoring of clinical status should be implemented to improve patient well-being during acute infection, but also prevent chronic nociceptive syndromes.

Pregabalin vs placebo to prevent chronic pain after whiplash injury in at-risk individuals: results of a feasibility study for a large randomised controlled trial

ABSTRACT

There are few effective treatments for acute whiplash-associated disorders (WADs). Early features of central sensitisation predict poor recovery. The effect of pregabalin on central sensitisation might prevent chronic pain after acute whiplash injury. This double blind, placebo-controlled randomised controlled trial examined feasibility and potential effectiveness of pregabalin compared with placebo for people with acute WAD. Twenty-four participants with acute WAD (<48 hours) and at risk of poor recovery (pain ≥5/10) were recruited from hospital emergency departments in Queensland, Australia, and randomly assigned by concealed allocation to either pregabalin (n = 10) or placebo (n = 14). Pregabalin was commenced at 75 mg bd, titrated to 300 mg bd for 4 weeks, and then weaned over 1 week. Participants were assessed at 5 weeks and 3, 6, and 12 months. Feasibility issues included recruitment difficulties and greater attrition in the placebo group. For the primary clinical outcome of neck pain intensity, attrition at 5 weeks was pregabalin: 10% and placebo: 36% and at 12 months was pregabalin: 10% and placebo: 43%. Pregabalin may be more effective than placebo for the primary clinical outcome of neck pain intensity at 3 months (mean difference: -4.0 [95% confidence interval -6.2 to -1.7]) on an 11-point Numerical Rating Scale. Effects were maintained at 6 months but not 12 months. There were no serious adverse events. Minor adverse events were more common in the pregabalin group. A definitive large randomised controlled trial of pregabalin for acute whiplash injury is warranted. Feasibility issues would need to be addressed with modifications to the protocol.

Challenges and visions for managing pain-related insomnia in primary care using the hybrid CBT approach: a small-scale qualitative interview study with GPs, nurses, and practice managers

Background

Chronic pain and insomnia have a complex, bidirectional relationship – addressing sleep complaints alongside pain may be key to alleviating patient-reported distress and disability. Healthcare professionals have consistently reported wanting to offer psychologically informed chronic pain management at the primary care level. Research in secondary care has demonstrated good treatment efficacy of hybrid CBT for chronic pain and insomnia. However, primary care is typically the main point of treatment entry, hence may be better situated to offer treatments using a multidisciplinary approach. In this study, primary care service providers’ perception of feasibility for tackling pain-related insomnia in primary care was explored.

Methods

The data corpus originates from a feasibility trial exploring hybrid CBT for chronic pain and insomnia delivered in primary care. This formed three in-depth group interviews with primary care staff (n = 9) from different primary care centres from the same NHS locale. All interviews were conducted on-site using a semi-structured approach. Verbal data was recorded, transcribed verbatim and analysed using the thematic analysis process.

Results

Eight themes were identified – 1) Discrepant conceptualisations of the chronic pain-insomnia relationship and clinical application, 2) Mismatch between patients’ needs and available treatment offerings, 3) Awareness of psychological complexities, 4) Identified treatment gap for pain-related insomnia, 5) Lack of funding and existing infrastructure for new service development, 6) General shortage of psychological services for complex health conditions, 7) Multidisciplinary team provision with pain specialist input, and 8) Accessibility through primary care. These mapped onto four domains - Current understanding and practice, Perceived facilitators, Perceived barriers, Ideal scenarios for a new treatment service – which reflected the focus of our investigation. Taken together these provide key context for understanding challenges faced by health care professionals in considering and developing a new clinical service.

Conclusions

Primary care service providers from one locale advocate better, multidisciplinary treatment provision for chronic pain and insomnia. Findings suggest that situating this in primary care could be a feasible option, but this requires systemic support and specialist input as well as definitive trials for success.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01552-3.

Why It Is Important to Consider the Effects of Analgesics on Sleep: A Critical Review

We review the known physiological mechanisms underpinning all of pain processing, sleep regulation, and pharmacology of analgesics prescribed for chronic pain. In particular, we describe how commonly prescribed analgesics act in sleep-wake neural pathways, with potential unintended impact on sleep and/or wake function. Sleep disruption, whether pain- or drug-induced, negatively impacts quality of life, mental and physical health. In the context of chronic pain, poor sleep quality heightens pain sensitivity and may affect analgesic function, potentially resulting in further analgesic need. Clinicians already have to consider factors including efficacy, abuse potential, and likely side effects when making analgesic prescribing choices. We propose that analgesic-related sleep disruption should also be considered. The neurochemical mechanisms underlying the reciprocal relationship between pain and sleep are poorly understood, and studies investigating sleep in those with specific chronic pain conditions (including those with comorbidities) are lacking. We emphasize the importance of further work to clarify the effects (intended and unintended) of each analgesic class to inform personalized treatment decisions in patients with chronic pain. © 2021 American Physiological Society. Compr Physiol 11:1-31, 2021.

Modulation of Pathological Pain by Epidermal Growth Factor Receptor

Chronic pain has been widely recognized as a major public health problem that impacts multiple aspects of patient quality of life. Unfortunately, chronic pain is often resistant to conventional analgesics, which are further limited by their various side effects. New therapeutic strategies and targets are needed to better serve the millions of people suffering from this devastating disease. To this end, recent clinical and preclinical studies have implicated the epidermal growth factor receptor signaling pathway in chronic pain states. EGFR is one of four members of the ErbB family of receptor tyrosine kinases that have key roles in development and the progression of many cancers. EGFR functions by activating many intracellular signaling pathways following binding of various ligands to the receptor. Several of these signaling pathways, such as phosphatidylinositol 3-kinase, are known mediators of pain. EGFR inhibitors are known for their use as cancer therapeutics but given recent evidence in pilot clinical and preclinical investigations, may have clinical use for treating chronic pain. Here, we review the clinical and preclinical evidence implicating EGFR in pathological pain states and provide an overview of EGFR signaling highlighting how EGFR and its ligands drive pain hypersensitivity and interact with important pain pathways such as the opioid system.

Supraorbital Nerve Radiofrequency for Severe Neuralgia Caused by Herpes Zoster Ophthalmicus

Background

Radiofrequency of the Gasserian ganglion can be used for ophthalmic herpetic neuralgia (OHN), but it is associated with complications. This study aimed to use the supraorbital nerve for computed tomography- (CT-) guided radiofrequency thermocoagulation to treat refractory OHN.

Methods

This was a retrospective case series study of patients with simple or combined OHN treated at our hospital between 06/2012 and 06/2018. The numerical rating score (NRS), spontaneous pain, allodynia, gabapentin dosage, paracetamol/oxycodone dosage, patient global impression of change (PGIC) score, Barrow numbness score, postoperative 360-day recurrence rate, and complications were recorded before the operation and at 1, 30, 90, 180, and 360 days after the operation.

Results

Compared with baseline, the NRS was decreased, and PGIC was increased at postoperative 1, 30, 90, 180, and 360 days, and the gabapentin and paracetamol oxycodone doses at postoperative 30, 90, 180, and 360 days were decreased (all P < 0.001). Compared with 1 day after the operation, numbness was decreased at 30, 90, 180, and 360 days after the operation (P < 0.001). Compared with baseline, the number of patients with allodynia at each time point after the operation was decreased (P < 0.001), but without a difference for spontaneous pain (P=0.407). No subjects showed drooping eyelid, corneal ulcers, eyeball damage, decreased vision, and other severe complications.

Conclusion

CT-guided supraorbital nerve radiofrequency thermocoagulation for the treatment of OHN can effectively relieve pain and reduce the dose of analgesics, without any serious complication. This study suggests that this technique is feasible and applicable to clinical practice.