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

Predicting chronic post-traumatic head and neck pain: the role of bedside parameters

ABSTRACT

Traumatic brain injury (TBI) annually impacts 69 million individuals worldwide. Mild TBI constitutes approximately 90% of all TBIs. Chronic pain post-mTBI occurs in 29% to 58% of patients. This study aims to introduce a predictive model for chronic pain development in individuals diagnosed with mild traumatic brain injury (mTBI) immediately postinjury. We included individuals who had sustained mTBI in motor vehicle accident (MVA). All patients had initial assessments within the first 72 hours (representing the subacute period) after the injury and performed follow-ups for 1 year. Machine learning model was applied to the integrated measures of clinical pain, pain-related psychological parameters, mTBI clinical signs, and sociodemographic information. This study included 203 patients experiencing acute head or neck pain attributable to mTBI post-MVA. We categorized these patients into 2 groups: patients who progressed to develop chronic head or neck pain (n = 89, 43.8%) and patients who recovered (low/mild pain) (n = 114, 56.2%). Severity of the subacute neck pain, number of painful body areas, and education years were identified as the most significant factors predicting chronic pain. The optimized predictive model demonstrated high efficacy, with an accuracy of 83%, a sensitivity of 92%, and an area under the receiver operating characteristic curve of 0.8. Our findings indicate feasibility in predicting chronic post-MVA pain within the critical 72-hour window postinjury using simple bedside metrics. This approach offers a promising avenue for the early detection of individuals at increased risk for chronic pain, enabling the implementation of targeted early interventions.

Chronic pain and comorbid posttraumatic stress disorder: Potential mechanisms, conceptualizations, and interventions

Posttraumatic stress disorder (PTSD) is a common comorbidity to chronic pain, among others due to potentially shared posttraumatic origin. There has been growing interest in this field in the past decades, also providing some important studies to support our understanding of this comorbidity and how to address it in clinical practice. However, there are still important questions, particularly regarding the potentially shared vulnerabilities, mutually maintaining mechanisms, and how to best treat this comorbidity. This article provides a brief and up-to-date review of what we argue to be some of the most important studies within the field of chronic pain and comorbid PTSD and will discuss some of the current challenges and ways forward.

Evidence for peripheral neuroinflammation after acute whiplash

ABSTRACT

Whiplash injury is associated with high socioeconomic costs and poor prognosis. Most people are classified as having whiplash-associated disorder grade II (WADII), with neck complaints and musculoskeletal signs, in the absence of frank neurological signs. However, evidence suggests that there is a subgroup with underlying nerve involvement in WADII, such as peripheral neuroinflammation. This study aimed to investigate the presence of neuroinflammation in acute WADII using T2-weighted magnetic resonance imaging of the brachial plexus, dorsal root ganglia and median nerve, and clinical surrogates of neuroinflammation: heightened nerve mechanosensitivity (HNM), raised serum inflammatory mediators, and somatosensory hyperalgesia. One hundred twenty-two WADII participants within 4 weeks of whiplash and 43 healthy controls (HCs) were recruited. Magnetic resonance imaging T2 signal ratio was increased in the C5 root of the brachial plexus and the C5-C8 dorsal root ganglia in WADII participants compared with HCs but not in the distal median nerve trunk. Fifty-five percent of WADII participants had signs of HNM. Inflammatory mediators were also raised compared with HCs, and 47% of WADII participants had somatosensory changes on quantitative sensory testing. In those WADII individuals with HNM, there was hyperalgesia to cold and pressure and an increased proportion of neuropathic pain. Many people with WADII had multiple indicators of neuroinflammation. Overall, our results present a complex phenotypic profile for acute WADII and provide evidence suggestive of peripheral neuroinflammation in a subgroup of individuals. The results suggest that there is a need to reconsider the management of people with WADII.

7. Cervical facet pain: Degenerative alterations and whiplash-associated disorder

INTRODUCTION

Pain from the cervical facet joints, either due to degenerative conditions or due to whiplash-related trauma, is very common in the general population. Here, we provide an overview of the literature on the diagnosis and treatment of cervical facet-related pain with special emphasis on interventional treatment techniques.

METHODS

A literature search on the diagnosis and treatment of cervical facet joint pain and whiplash-associated disorders (WAD) was performed using PubMed, Cochrane, and Embase databases. All relevant literature was retrieved and summarized.

RESULTS

Facet-related pain is typically diagnosed based on history and physical examination of the patients, combined with a diagnostic block (eg, with local anesthetic) of the medial branches innervating the joints. There is no additive value for imaging techniques to diagnose cervical facet pain, but imaging may be used for procedure planning. First-line therapy for pain treatment includes focused exercise, graded activity, and range-of-motion training. Pharmacological treatment may be considered for acute facet joint pain; however, for chronic facet joint pain, evidence for pharmacological treatment is lacking. Considering the lack of evidence for treatment with botulinum toxin, intra-articular steroid injections, or surgery, these interventions are not recommended. Diagnostic blocks are not considered a viable treatment option, though some patients may experience a prolonged analgesic effect. Long-term analgesia (>6 months) has been observed for radiofrequency treatment of the medial branches.

CONCLUSIONS

Cervical facet pain is diagnosed based on history, physical examination, and a diagnostic block of the medial branches innervating the painful joints. Conservative management, including exercise therapy, is the first line of treatment. When conservative management does not result in adequate improvement of pain, radiofrequency treatment of the medial branches should be considered, which often results in adequate pain relief.

Recruitment and retention for chronic pain clinical trials: a narrative review

Opioid misuse is at a crisis level. In response to this epidemic, the National Institutes of Health has funded $945 million in research through the Helping to End Addiction Long-term (HEAL) Pain Management Initiative, including funding to the Vanderbilt Recruitment Innovation Center (RIC) to strategize methods to catalyze participant recruitment. The RIC, recognizing the challenges presented to clinical researchers in recruiting individuals experiencing pain, conducted a review of evidence in the literature on successful participant recruitment methods for chronic pain trials, in preparation for supporting the HEAL Pain trials. Study design as it affects recruitment was reviewed, with issues such as sufficient sample size, impact of placebo, pain symptom instability, and cohort characterization being identified as problems. Potential solutions found in the literature include targeted electronic health record phenotyping, use of alternative study designs, and greater clinician education and involvement. For retention, the literature reports successful strategies that include maintaining a supportive staff, allowing virtual study visits, and providing treatment flexibility within the trial. Community input on study design to identify potential obstacles to recruitment and retention was found to help investigators avoid pitfalls and enhance trust, especially when recruiting underrepresented minority populations. Our report concludes with a description of generalizable resources the RIC has developed or adapted to enhance recruitment and retention in the HEAL Pain studies. These resources include, among others, a Recruitment and Retention Plan Template, a Competing Trials Tool, and MyCap, a mobile research application that interfaces with Research Electronic Data Capture (REDCap).

Nerve pathology and neuropathic pain after whiplash injury: a systematic review and meta-analysis

ABSTRACT

There is no clear understanding of the mechanisms causing persistent pain in patients with whiplash-associated disorder (WAD). The aim of this systematic review was to assess the evidence for nerve pathology and neuropathic pain in patients with WAD. EMBASE, PubMed, CINAHL (EBSCO), and MEDLINE were searched from inception to September 1, 2020. Study quality and risk of bias were assessed using the Newcastle-Ottawa Quality Assessment Scales. Fifty-four studies reporting on 390,644 patients and 918 controls were included. Clinical questionnaires suggested symptoms of predominant neuropathic characteristic in 34% of patients (range 25%-75%). The mean prevalence of nerve pathology detected with neurological examination was 13% (0%-100%) and 32% (10%-100%) with electrodiagnostic testing. Patients independent of WAD severity (Quebec Task Force grades I-IV) demonstrated significantly impaired sensory detection thresholds of the index finger compared with controls, including mechanical (SMD 0.65 [0.30; 1.00] P < 0.005), current (SMD 0.82 [0.25; 1.39] P = 0.0165), cold (SMD -0.43 [-0.73; -0.13] P = 0.0204), and warm detection (SMD 0.84 [0.25; 1.42] P = 0.0200). Patients with WAD had significantly heightened nerve mechanosensitivity compared with controls on median nerve pressure pain thresholds (SMD -1.10 [-1.50; -0.70], P < 0.0001) and neurodynamic tests (SMD 1.68 [0.92; 2.44], P = 0.0004). Similar sensory dysfunction and nerve mechanosensitivity was seen in WAD grade II, which contradicts its traditional definition of absent nerve involvement. Our findings strongly suggest a subset of patients with WAD demonstrate signs of peripheral nerve pathology and neuropathic pain. Although there was heterogeneity among some studies, typical WAD classifications may need to be reconsidered and include detailed clinical assessments for nerve integrity.