Complex regional pain syndrome what is the outcome? - a systematic review of the course and impact of CRPS at 12 months from symptom onset and beyond

Is CRPS-1 a Chronic Disabling Disease? A Long-term, Real-Life Study on Patients Treated With Neridronate

Background

Complex Regional Pain Syndrome type 1 (CRPS-1) is severely debilitating and painful disease that is difficult to treat.

Objective

The objective was to evaluate the long-term residual disability of patients with CRPS-1 following parenteral neridronate treatment.

Design

This is real-life retrospective observational study.

Methods

Patients affected by CRPS-1 of the upper limb were treated with neridronate infusions (400 mg over 10 days) between February 2017 and December 2021 for whom clinical and demographic information was collected. From November 2022, patients treated ⩾1 year previously were recalled for clinical evaluation. A dedicated instrument (DASH questionnaire, Disabilities of the Arm, Shoulder and Hand) was employed to assess residual disability. Multivariate logistic regression analysis was used to investigate predictors of disability.

Results

Forty-nine patients aged 61.1 ± 11.5 years and 73.5% female with CRPS-1 of the upper limb were included. Disease duration before treatment was 9.9 ± 8.0 weeks, and the mean length of follow-up was 4 years (47.7 ± 22.0 months). The disease had fully resolved in 46 patients (93.9%) for whom the diagnostic criteria were no longer recognized. According to the DASH score, 38 patients (77.6%) resulted free of functional limitations, whereas 11 patients (22.4%) were still suffering from disability. The DASH score was positively correlated with residual visual analogue scale (VAS; Spearman's Rho = 0.61; P < .001). Predictors of residual disability were younger age (odds ratio [OR]: 0.77, 95% CI: 0.63-0.93; P = .012) and delay between disease onset and treatment (OR: 1.45, 95% CI: 1.13-1.96; P = .004).

Conclusions

In this real-life study, neridronate parenteral treatment provided a full recovery of CRPS-1 in over 3 quarters of patients, provided they are treated early.

Complex regional pain syndrome type II localized to the index finger. A case report translating scientific evidence into clinical practice

BACKGROUND

Complex regional pain syndrome type II (CRPS-II) is a rare condition associated with peripheral nervous system lesions. Its localized distribution in the fingers is unique, and its treatment is unclear.

CASE DESCRIPTION

A 56-year-old male presented to the emergency department with a saw-cut index finger injury with associated tendon and nerve injuries. After surgery, he was admitted to physical therapy (PT) with persistent pain, joint stiffness, allodynia, and trophic changes compatible with CRPS-II localized in the index finger. The diagnosis was confirmed after applying the Budapest Criteria, and PT was progressive and individualized according to the patient's needs, including graded motor imagery, mobilizations, exercises, and education.

OUTCOMES

After 12 weeks of PT, a clinically significant decrease in pain intensity and improvements in mobility and index finger and upper limb functionality was observed, reducing CRPS symptomatology.

DISCUSSION

This report provides information about a unique case of a localized form of CRPS-II. After reviewing the literature on clinical cases of both CRPS-II and localized forms of CRPS, we highlight that the clinical features of this patient and his positive therapeutic response support the importance of translating the scientific evidence on CRPS into clinical practice.

Complex Regional Pain Syndrome: a cross-sectional study of physical symptoms, disability, and psychological health in long term

Introduction

Knowledge about long-time residual symptoms, disabilities, and psychological health in complex regional pain syndrome (CRPS) is limited.

Objectives

The aim was to evaluate outcome, focusing on physical symptoms, disability, and psychological health, in individuals with CRPS through a cross-sectional survey study.

Methods

Individuals with a confirmed diagnosis of CRPS were identified through medical charts and sent validated survey forms (Disabilities of the Arm, Shoulder and Hand-Quick version, Specific Hand Surgery Questionnaire-8 questions, EuroQol 5 Dimensions 3 levels, Life Satisfaction Questionnaire-11, Hospital Anxiety and Depression Scale, Pain Catastrophizing Scale, and Sense of Coherence-29) and complementary questions.

Results

Responders (response rate: 99/238, 42%; CRPS type 1: 72%; CRPS type 2: 28%; time since diagnosis median: 59 [34-94] months) reported remaining symptoms and disability (Disabilities of the Arm, Shoulder and Hand-Quick version score: 45 [20-70]) and more improvement in type 1 than in type 2. Only 9% of individuals with CRPS reported no residual pain or discomfort. Approximately 60% had problems in daily activities, 49% had sleeping problems, and 90% experienced moderate-extreme pain with 23% still on sick leave. The Hospital Anxiety and Depression Scale survey revealed significantly higher scores than a Swedish reference population. Individuals with a low Sense of Coherence and high pain catastrophizing had worse disability and were less satisfied with their lives and physical and psychological health. A lower level of education and more anxiety were associated with worsened disability over time.

Conclusion

Individuals with CRPS suffer in the long term from pain, sleeping problems, and limitations in daily activities with occurrence of anxiety and depression, resulting in dissatisfaction with many aspects of their lives. A low Sense of Coherence and high pain catastrophizing are associated with a worse outcome. Biopsychosocial aspects should be addressed in clinical practice.

Chronic pain in pediatrics

This paper provides an overview of pediatric patients suffering from chronic pain and the best practices for treating this challenging patient population. With newer technologies and therapies emerging for pediatric patients in chronic pain, there are now opportunities to provide comprehensive therapies that lead to long-term improvements in outcomes. The paper discusses alternatives to opioid therapies in order to provide an overview of treatments for pediatric patients with chronic pain. It also explores best practices for opioid management and the newest devices as direct therapies for pediatric chronic pain patients. The paper extensively discusses multidisciplinary clinics, opioid alternatives, and interventions, and includes resources for patients, families, and healthcare providers for further education.

Bone Scintigraphy in 2 Cases of Complex Regional Pain Syndrome

ABSTRACT

A 59-year-old woman was presented to the outpatient clinic with persistent pain after a hyperextension/inversion trauma of the ankle. Six months after the incident, a 3-phase bone scan was performed. A second patient, a 54-year-old man, was referred for a 3-phase bone scan 2 months after his right hand was twisted while using a drill. In both patients, scintigraphy showed diffuse increased uptake in the affected limb in all 3 phases. The x-rays of the affected limbs showed osteopenia. These findings are consistent with (early phase) complex regional pain syndrome.

[Prospective, multicenter study of the outcome of complex regional pain syndrome after 12 months]

BACKGROUND AND OBJECTIVES

Complex regional pain syndrome (CRPS) can lead to severe pain and limited functionality in the long term. Guidelines should help to optimize treatment procedures. It should be investigated which outcome is achieved after 1 year with guideline-based therapy.

MATERIALS AND METHODS

In a prospective multicenter study, 40 patients with newly diagnosed CRPS were examined to determine how their pain and functional limitations changed within 1 year. In addition, it was investigated whether the time of diagnosis and invasive measures influence these outcome parameters.

RESULTS

All patients received physiotherapy and/or ergotherapy, treatment with glucocorticoids and/or bisphosphonates 29 (72.5%); various invasive measures were carried out in 13 (32.5%). After 1 year, both pain and functionality were significantly improved; two-thirds reported a tolerable average pain intensity. Severe functional impairment according to von Korff disability points was found after 1 year in 9 (22.5%), and a moderate or severe impairment according to medical evaluation in 6 (15%) and 3 (7.5%) patients, respectively. Earlier diagnosis and corresponding earlier start of treatment correlated with better outcome in terms of pain and functionality according to von Korff, but not according to medical evaluation. The influence of invasive procedures on the outcome parameters tended to be low.

CONCLUSION

Guideline-based treatment led to a good outcome in terms of pain and functionality in the majority of patients. Early diagnosis correlated with better outcome, so suspected cases should be referred quickly to a medical facility with appropriate expertise.

Refractory CRPS pain treated with psilocybin: A case report

Psilocybin shows promise as a treatment for CRPS, offering significant pain relief and functional improvement in a patient with refractory symptoms. This case highlights the need for further research into psilocybin's efficacy and optimal dosing for chronic pain management.

Monitoring Everyday Upper Extremity Function in Patients with Complex Regional Pain Syndrome: A Secondary, Retrospective Analysis from ncRNAPain

Objective

Complex regional pain syndrome (CRPS) represents a rare complication following injury to a limb. The DASH questionnaire (disability of arm, shoulder, and hand) evaluates everyday arm function. We assessed the DASH and its subitems in comparison to patients with brachial plexus lesions or fracture controls, analysed it over time, and in relation to active range of motion (ROM), to determine patients' impairment and trajectory.

Methods

The dataset included 193 patients with upper extremity CRPS from the noncoding RNA (ncRNA) Pain cohort, 36 fracture controls, and 12 patients with traumatic brachial plexus lesions. For the clinical and psychological characterisation, questionnaires and a goniometer for the measurement of ROM were utilized. Thirty-three patients were followed up after approximately 2.5 years of guideline treatment.

Results

CRPS patients had a similar mean DASH of 54.7 (standard deviation (S.D.) ±21) as brachial plexus lesion patients (M = 51.4, S.D. ± 16.1) but different significantly from fracture controls (M = 21.2, S.D. ± 21.1). Pain and older age were predictors of the DASH. Activities requiring force or impact on the arm, shoulder, or hand were mostly affected in patients with CRPS. After 2.5 years of standard treatment, the mean DASH score fell to 41.3 (S.D. ± 25.2), weakness in leisure activities was recuperated, pain feelings were lessened, and ROM, e.g., wrist flexion, recovered by 36°. Two-thirds of patients improved in both the DASH and the ROM.

Conclusions

CRPS is as disabling as a complete loss of arm function in brachial plexus lesions and exhibits only partial recovery. Developing QuickDASH versions for CRPS patients could reduce the load of questions in clinical studies. It would be prudent to consider the unexpected age dependency of the DASH in future studies. This trial is registered with DRKS00008964.

Complex Regional Pain Syndrome in a Non-traumatic Case: A Case Report

Complex regional pain syndrome (CRPS) is an uncommon neuropathic pain illness characterized by extreme discomfort, muscular weakness, limb edema, and hyperhidrosis. Fracture, surgery, stroke, and spinal cord damage are all potential risk factors. This case report study provides a detailed description of no-traumatic CRPS, a complex pain illness characterized by sensory, vasomotor, sudomotor, motor, trophic, and edematous changes and persistent discomfort. We reported a case of a 39-year-old male with a seven-year history of severe right shoulder-hand pain. He presented with recurrent hand and shoulder pain characterized by burning sensations and weakness, despite not having experienced this before, and he denied any history of trauma or fracture. Surgical procedure and pharmaceutical therapy were provided, but there was no outcome, as evidenced by the patient's clinical condition and the medical records. Despite extensive investigation, no imaging or laboratory tests have been developed for diagnosis, necessitating further research for a comprehensive understanding and diagnosis.

Mechanisms of complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is a chronic pain disorder characterized by a diverse array of symptoms, including pain that is disproportionate to the initial triggering event, accompanied by autonomic, sensory, motor, and sudomotor disturbances. The primary pathology of both types of CRPS (Type I, also known as reflex sympathetic dystrophy, RSD; Type II, also known as causalgia) is featured by allodynia, edema, changes in skin color and temperature, and dystrophy, predominantly affecting extremities. Recent studies started to unravel the complex pathogenic mechanisms of CRPS, particularly from an autoimmune and neuroimmune interaction perspective. CRPS is now recognized as a systemic disease that stems from a complex interplay of inflammatory, immunologic, neurogenic, genetic, and psychologic factors. The relative contributions of these factors may vary among patients and even within a single patient over time. Key mechanisms underlying clinical manifestations include peripheral and central sensitization, sympathetic dysregulation, and alterations in somatosensory processing. Enhanced understanding of the mechanisms of CRPS is crucial for the development of effective therapeutic interventions. While our mechanistic understanding of CRPS remains incomplete, this article updates recent research advancements and sheds light on the etiology, pathogenesis, and molecular underpinnings of CRPS.

Patients' experiences of treatment-relevant processes in multimodal pain rehabilitation for severe complex regional pain syndrome - a qualitative study

PURPOSE

Complex regional pain syndrome (CRPS) is a longstanding condition with spontaneous and evoked pain, that usually occurs in an upper or lower extremity. Although it often resolves within the first year, it may for a minority progress to a chronic and occasionally severely disabling condition. The aim of this study was to explore patients' experiences and perceived effects of a specific treatment, designed for patients with severe and highly disabling CRPS, in order to identify possible treatment-relevant processes.

METHODS

The method used was a qualitative design, using semi-structured interviews with open-ended questions to capture participants' experiences and perceptions. Ten interviews were analyzed using applied thematic analysis.

RESULTS

Despite the fact that participants had a severe conditions, including nerve damage and a long duration of illness, they reported having been helped to increase flexible persistence, reduce fear and avoidance, and improve connections. This helped participants to significant improvements in daily life functioning.

CONCLUSIONS

The participants described distinct possible treatment-relevant processes leading to a substantial improvement in everyday life. The results imply that there is hope for this group that has been severely disabled for many years. This may help guide future clinical treatment trials.

Complex regional pain syndrome: advances in epidemiology, pathophysiology, diagnosis, and treatment

Complex regional pain syndrome (CRPS) is a rare pain disorder that usually occurs in a limb after trauma. The features of this disorder include severe pain and sensory, autonomic, motor, and trophic abnormalities. Research from the past decade has offered new insights into CRPS epidemiology, pathophysiology, diagnosis, and treatment. Early identification of individuals at high risk of CRPS is improving, with several risk factors established and some others identified in prospective studies during the past 5 years. Better understanding of the pathophysiological mechanisms of CRPS has led to its classification as a chronic primary pain disorder, and subtypes of CRPS have been updated. Procedures for diagnosis have also been clarified. Although effective treatment of CRPS remains a challenge, evidence-based integrated management approaches provide new opportunities to improve patient care. Further advances in diagnosis and treatment of CRPS will require coordinated, international multicentre initiatives.

Transient immune activation without loss of intraepidermal innervation and associated Schwann cells in patients with complex regional pain syndrome

BACKGROUND

Complex regional pain syndrome (CRPS) develops after injury and is characterized by disproportionate pain, oedema, and functional loss. CRPS has clinical signs of neuropathy as well as neurogenic inflammation. Here, we asked whether skin biopsies could be used to differentiate the contribution of these two systems to ultimately guide therapy. To this end, the cutaneous sensory system including nerve fibres and the recently described nociceptive Schwann cells as well as the cutaneous immune system were analysed.

METHODS

We systematically deep-phenotyped CRPS patients and immunolabelled glabrous skin biopsies from the affected ipsilateral and non-affected contralateral finger of 19 acute (< 12 months) and 6 chronic (> 12 months after trauma) CRPS patients as well as 25 sex- and age-matched healthy controls (HC). Murine foot pads harvested one week after sham or chronic constriction injury were immunolabelled to assess intraepidermal Schwann cells.

RESULTS

Intraepidermal Schwann cells were detected in human skin of the finger-but their density was much lower compared to mice. Acute and chronic CRPS patients suffered from moderate to severe CRPS symptoms and corresponding pain. Most patients had CRPS type I in the warm category. Their cutaneous neuroglial complex was completely unaffected despite sensory plus signs, e.g. allodynia and hyperalgesia. Cutaneous innate sentinel immune cells, e.g. mast cells and Langerhans cells, infiltrated or proliferated ipsilaterally independently of each other-but only in acute CRPS. No additional adaptive immune cells, e.g. T cells and plasma cells, infiltrated the skin.

CONCLUSIONS

Diagnostic skin punch biopsies could be used to diagnose individual pathophysiology in a very heterogenous disease like acute CRPS to guide tailored treatment in the future. Since numbers of inflammatory cells and pain did not necessarily correlate, more in-depth analysis of individual patients is necessary.

Subtypes of complex regional pain syndrome-a systematic review of the literature

To systematically identify and summarize possible subtypes of complex regional pain syndrome (CRPS), we searched MEDLINE, Embase, Cochrane, Scopus, and Web of Science for original studies reporting or investigating at least one subtype within a group of patients with CRPS. The search retrieved 4239 potentially relevant references. Twenty-five studies met our inclusion criteria and were included in the analysis. Complex regional pain syndrome phenotypes were investigated based on the following variables: clinical presentation/sensory disturbances, dystonia, skin temperature, disease duration, onset type, CRPS outcome, and neuropsychological test performance. Support was found for the following CRPS subtypes: CRPS type I, CRPS type II, acute CRPS, chronic CRPS, centralized CRPS, cold CRPS, warm CRPS, inflammatory CRPS, dystonic CRPS, nondystonic CRPS, familial CRPS, and nonfamilial CRPS. It is unclear whether these are distinct or overlapping subtypes. The results of this comprehensive review can facilitate the formulation of well-defined CRPS subtypes based on presumed underlying mechanisms. Our findings provide a foundation for establishing and defining clinically meaningful CRPS subtypes, with the ultimate goal of developing targeted and enhanced treatments for CRPS.

Participatory design of an infographic to help support the care of people living with complex regional pain syndrome

Background

Complex regional pain syndrome (CRPS) can be a debilitating pain condition with enduring physical, psychological and social impacts. CRPS is often poorly understood by healthcare professionals and management needs to be tailored to each individual's presentation. People with lived experience express difficulty in accessing reliable and meaningful information about the condition. This study aimed to co-create a trustworthy infographic to share information about the lived experience of CRPS.

Methods

We adopted a seven-phase, iterative, participatory methodology to co-create the infographic. Potential infographic content was obtained from qualitative work investigating the lived experience of CRPS. Online consumer engagement (people with doctor diagnosed CRPS/their family, n=20) was used to prioritise content to be included in the infographic and then potential designs were sourced. The research team narrowed the selections down to two designs which were presented to consumers online for final selection (n=25) and refinement (n=34).

Results

An infographic for understanding the lived experience of CRPS was completed using participatory design, providing a resource aligned to the needs of people with this condition. Using the Patient Education Materials Assessment Tool, the final infographic rated highly for understandability (92%) and participants indicated significant willingness to share this infographic with others (93%).

Conclusion

A process of participatory design was an effective and efficient process for translation of evidence gathered from qualitative research into a trustworthy resource for people with CRPS and their support people.

An Unusual Presentation of Complex Regional Pain Syndrome Type 1

Complex regional pain syndrome (CRPS) is a chronic neurologic painful disorder usually present after a traumatic insult. It is divided into two subtypes based on the absence of a significant nerve injury: type 1 or dystrophy and type 2 or causalgia. The exact mechanism still needs to be fully understood. The management of CRPS requires a multidisciplinary team approach with a rehabilitation program and physical and occupational therapies. We present a case report of a 22-year-old Saudi female with no medical or surgical history who presented to the clinic with severe pain, swelling, and discoloration in the left lower limb associated with unusual symptoms of non-epileptic convulsion attack and short-term memory loss for three years that increased in intensity. There was marked swelling and discoloration of the left lower limb, which was more significant at the foot, and the limb was tender and warm to the touch and allodynia. A slight touch to the limb led to a whole-body non-epileptic convulsion lasting for less than 30 seconds and loss of short-term memory and consciousness following the convulsion attack. A multidisciplinary team primarily managed the patient. In this case, the rarity and refractory to medical management emphasize the importance of understanding the different therapeutic modalities in managing this syndrome. However, more studies are warranted to understand the exact cause, pathogenesis, and available treatment options.

[Complementary methods in the treatment of complex regional pain syndrome]

BACKGROUND

Complex regional pain syndrome (CRPS) affects 10-15% of patients following injuries (fractures, surgery) to the outer extremities and people after a stroke. The affected area hurts, is inflamed and lacks strength, while mobility and sensitivity are restricted. Complementary medicine as part of integrative medicine offers additional effective treatment options.

RESEARCH QUESTION

Complementary therapies that extend the guideline recommendations, demonstrate clinical evidence and/or are plausible are presented.

RESULTS

Mind-body medicine procedures (mindfulness, relaxation, yoga, Qi Gong, etc.) support the patient's self-efficacy and stimulate the vagus nerve as well as promoting the reduction of pain, depression and anxiety and improving quality of life. Phytotherapeutics such as turmeric or stinging nettle have an anti-inflammatory effect. Water treatments reduce pain, and acupuncture and neural therapy can be tried.

CONCLUSIONS

Integrative, complementary medical therapy options support the CRPS patient in coping with their disease and the related pain. These options can play an important role in the multimodal, interdisciplinary treatment of this disease.

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.

[Complex Regional Pain Syndrome (CRPS) - State of the Art in Diagnostics and Therapy]

The complex regional pain syndrome (CRPS) usually occurs within a few weeks in 2-5% of all patients after trauma or surgery or subsequent measures of the distal extremities. There are certain risk factors for its occurrence but no "CRPS personality", instead there are factors that negatively influence the course. The prognosis is generally good ("rule of thirds"), but remaining limitations are common. The diagnosis is clinically possible according to the "Budapest criteria". Additional examinations are possible in case of doubt but are neither conclusive nor exclusive. Corticoids and bisphosphonates are used alongside drugs that have an effect on neuropathic pain. Invasive therapies do not have good evidence and have therefore lost their importance. The rehabilitative therapy is carried out actively and with a lot of self-exercises at an early stage. Invasive anesthetic, passive therapies are obsolete. Special forms of treatment are "graded exposure" (GEXP) in the case of dominant anxiety and, e.g., "graded motor imagery" (GMI) in case of neglect-like symptoms. In addition to educational and behavioral therapy elements, psychotherapy for CRPS also includes participation as part of graded exposure.

Molecular and clinical markers of pain relief in complex regional pain syndrome: An observational study

BACKGROUND

Complex regional pain syndrome (CRPS) is marked by disproportionate pain after trauma. Whilst the long-term outcome is crucial to patients, predictors or biomarkers of the course of pain or CRPS symptoms are still lacking. In particular, microRNAs, such as miR-223, decreased in CRPS, have been described only in cross-sectional studies.

METHODS

In this study, we characterised CRPS patients over a course of 2.5 years of standard treatment. The patient underwent clinical examination including pain measurement, symptom questionnaires, quantitative sensory testing (QST) and blood sampling. Exosomal microRNA levels were measured via qPCR. After follow-up, patients were stratified into 'pain relief' (mean pain reduced by ≥2 numeric rating scale) or 'persistence' (mean pain unchanged or worsened). The primary outcome was miR-223 and miR-939 expression, secondary outcomes were differences in clinical parameters between groups and time points.

RESULTS

Thirty-nine patients were included, 33 of whom qualified for stratification. Overall, patients reported lower pain and improved clinical characteristics after 2.5 years, but no significant changes in QST or miR-223 and miR-939 expression levels. 16 patients met the criteria for pain relief. This was associated with stable exosomal miR-223 expression, whilst levels further decreased in pain persistence. Clinically, pain relief was marked by shorter disease duration and correlated positively with high initial pain.

CONCLUSION

We identified progressively reduced miR-223 as a putative biomarker of chronic CRPS pain. Clinically, this study underlines the importance of early diagnosis and treatment showing that high initial pain does not predict an unfavourable outcome. Finally, pain relief and recovery of sensory disturbances seem independent processes.

Healthcare Costs, Time to Fitness for Work, and Related Factors in Chronic Complex Regional Pain Syndrome: A Comparative and Longitudinal Study of 5-Year Follow-Up

Purpose

To assess and compare the healthcare costs, time to fitness for work (TFW) between chronic complex regional pain syndrome (CRPS) and non-CRPS; and identify factors associated with these outcomes in a comparative longitudinal study.

Patients and Methods

148 patients with chronic CRPS of the hand and 273 patients with chronic hand impairments but without CRPS (non-CRPS) were admitted at a Swiss rehabilitation clinic between 2007 and 2016. Healthcare costs and TFW were retrieved from insurance data over 5 years after the accident. Socio-demographic factors, biopsychosocial complexity measured by means of the INTERMED questionnaire, pain intensity and DASH disability scores were collected during rehabilitation. Generalized estimation equations and Cox proportional-hazards models were used to identify factors associated with outcomes.

Results

Healthcare costs were increased by 20% for the CRPS versus non-CRPS group (coefficient = 1.20, 95% CI = 1.08-1.35, p<0.001). The median TFW was longer for CRPS than non-CRPS patients (816 vs 672 days, p = 0.02). After adjusting for covariates, TFW did not differ between the two groups (hazard ratio = 0.94, 95% CI = 0.73-1.21, p=0.61). For CRPS patients, higher healthcare costs were associated with severe or moderate initial injury, high INTERMED or DASH disability scores. Longer TFW were associated with severe initial injury, low educational level, no work contract, and high INTERMED or DASH disability scores.

Conclusion

Overall, the healthcare costs were higher for CRPS than non-CRPS patients, but the TFW was comparable. We demonstrated also the significant associations of disability and biopsychosocial factors with the healthcare costs and TFW in CRPS patients.

Modern Principles of Diagnosis and Treatment in Complex Regional Pain Syndrome

BACKGROUND

Background: Complex regional pain syndrome (CRPS) is a relatively common complication, occurring in 5% of cases after injury or surgery, particularly in the limbs. The incidence of CPRS is around 5-26/100 000. The latest revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11) now categorizes CRPS as a primary pain condition of multifactorial origin, rather than a disease of the skeletal system or the autonomic nervous system.

METHODS

Method: Based on a selective search of the literature, we summarize current principles for the diagnosis and treatment of CRPS.

RESULTS

Results: Regional findings in CRPS are accompanied by systemic symptoms, especially by neurocognitive disorders of body perception and of symptom processing. The therapeutic focus is shifting from predominantly passive peripheral measures to early active treatments acting both centrally and peripherally. The treatment is centered on physiotherapy and occupational therapy to improve sensory perception, strength, (fine) motor skills, and sensorimotor integration/ body perception. This is supported by stepped psychological interventions to reduce anxiety and avoidance behavior, medication to decrease inflammation and pain, passive physical measures for reduction of edema and of pain, and medical aids to improve functioning in daily life. Interventional procedures should be limited to exceptional cases and only be performed in specialized centers. Spinal cord and dorsal root ganglion stimulation, respectively, are the interventions with the best evidence.

CONCLUSION

Conclusion: The modern principles for the diagnosis and treatment of CRPS consider both, physiological and psychological mechanisms, with the primary goal of restoring function and participation. More research is needed to strengthen the evidence base in this field.

Long-term efficacy and safety of neridronate treatment in patients with complex regional pain syndrome type 1: a pre-specified, open-label, extension study

Background

No data on the permanent and curative effect of bisphosphonate treatment in patients with complex regional pain syndrome type-1 (CRPS-1) are currently available. The aim of this pre-specified, open-label, observational study was to evaluate the long-term efficacy and safety of neridronate treatment.

Design

A pre-specified, open-label, extension study.

Methods

Patients treated with intramuscular (IM) placebo in the double-blind phase of the study were assigned to 100 mg intravenous (IV) neridronate treatment administered 4 times over 10 days. These patients, together with those previously treated with 400 mg IM neridronate, were followed for 1 year. Efficacy was assessed using a visual analogue scale (VAS) pain score. Changes in clinical signs and symptoms, quality of life (QoL) using the Short Form Health Survey (SF-36), and the McGill Pain Questionnaire were also assessed.

Results

Benefits on pain, clinical and functional measures were maintained and further improved over 12 months in most patients treated with neridronate administered either IM or IV. In IM-treated patients, the percentage of those defined as responders (VAS score reduction ≥ 50%) progressively increased up to day 360 to 32 of 35 patients (91.4%). Among the 27 patients referred to as responders at the end of the double-blind phase, 26 reported the same result at day 360 (96.3%). In IV-treated patients, a responder rate of 88% (22 out 25) was found at day 360 (p = 0.66 between groups). Consistent improvements were also observed for all clinical signs and functional questionnaire. No drug-related adverse events were reported during the study.

Conclusion

In patients with acute CRPS-1, the benefit in pain, clinical, and functional measures observed a few weeks after neridronate treatment administered either IM or IV is maintained and further improved over 12 months. Parenteral neridronate induces permanent disease remission preventing chronic pain and motor dysfunction.

Trial registration

EU Clinical Trials Register (EudraCT Number): 2014-001156-28.