Complex regional pain syndrome (CRPS), a review

A brief review of complex regional pain syndrome and current management

Complex regional pain syndrome (CRPS) is a debilitating chronic pain condition that, although exceedingly rare, carries a significant burden for the affected patient population. The complex and ambiguous pathophysiology of this condition further complicates clinical management and therapeutic interventions. Furthermore, being a diagnosis of exclusion requires a diligent workup to ensure an accurate diagnosis and subsequent targeted management. The development of the Budapest diagnostic criteria helped to consolidate existing definitions of CRPS but extensive work remains in identifying the underlying pathways. Currently, two distinct types are identified by the presence (CRPS type 1) or absence (CRPS type 2) of neuronal injury. Current management directed at this disease is broad and growing, ranging from non-invasive modalities such as physical and psychological therapy to more invasive techniques such as dorsal root ganglion stimulation and potentially amputation. Ideal therapeutic interventions are multimodal in nature to address the likely multifactorial pathological development of CRPS. Regardless, a significant need remains for continued studies to elucidate the pathways involved in developing CRPS as well as more robust clinical trials for various treatment modalities.

Economic evaluation of management strategies for complex regional pain syndrome (CRPS)

Background: The economic impact of Complex Regional Pain Syndrome (CRPS) on both patients and the global healthcare system continues to escalate. However, the economic implications associated with management interventions for CRPS have received limited attention. Therefore, our objective is to perform a thorough examination of published economic assessments of the various management strategies utilized for CRPS. Methods: A thorough search spanning four general medical databases and three health economic databases to identify full economic evaluations on CRPS management strategies from January 1994 to June 2023 were conducted. The quality of these studies were evaluated by employing the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement. To enable cross-study comparisons conducted in different countries, we adjusted the costs reported in the selected studies for inflation and converted them into 2023 US dollars. Results: A total of nine economic evaluations, consisting of eight high-quality and one medium-quality, were identified across five nations during a span of 29 years. The findings suggest that the most economically efficient intervention for CRPS are interventional approaches of Spinal Cord Stimulation (SCS) in comparison to conventional management for long periods of time. Furthermore, in situations where there is a limited time period of less than 1 year, rehabilitation therapies, particularly physical therapy, have been demonstrated to be more effective in terms of both cost and clinical outcomes. Conclusion: The interventional management strategies, particularly for severe and persistent CRPS over long periods, may offer the greatest cost efficiency. In conditions with limited timelines, rehabilitation measures, such as rehabilitation therapies, can be cost-effective. However, insufficient data for other common interventions prevents the formation of a definitive conclusion. Similarly, it is crucial to recognize that the results of these interventions might be affected by the selection of comparator and the threshold for willingness to pay.

Effectiveness of pulsed electromagnetic field therapy in the management of complex regional pain syndrome type 1: A randomized-controlled trial

Objectives: This study aims to investigate whether pulsed electromagnetic field (PEMF) therapy in addition to a conventional rehabilitation program is effective on pain and functioning in patients with type 1 complex regional pain syndrome (CRPS-1) of the hand.

Patients and methods: Between March 2013 and January 2015, a total of 32 patients (16 males, 16 females; mean age: 50.1±13.1 years; range, 25 to 75 years) were included. The patients were randomly allocated into two groups. The control group (n=16) received a conventional rehabilitation program consisting of physical modalities, exercises, and occupational therapy, whereas the PEMF group (n=16) received additional PEMF (8 Hz, 3.2 mT) to the affected hand. The primary outcome measure was pain intensity using the Numeric Rating Scale (NRS). Secondary outcome measures were grip and pinch strength, hand edema, hand dexterity, and hand activities. All patients received 20 therapy sessions (five sessions/week, four weeks in total) and were evaluated before and after the therapy and at the first-month follow-up.

Results: Both groups showed significant improvements in primary and secondary outcomes (p<0.05) after the therapy and at follow-up. When the groups were compared in terms of improvements in assessment parameters, no statistically significant difference was found between the two groups in any of the outcomes (p>0.05).

Conclusion: The PEMF in addition to conventional rehabilitation program did not provide additional benefit for pain and hand functions in CRPS-1. Future studies using different application parameters such as frequency, intensity, duration, and route may provide a better understanding of the role of PEMF in CRPS-1 treatment.

Pain, disability, and lifestyle: Patients with complex regional pain syndrome compared to chronic musculoskeletal pain - a retrospective analysis

BACKGROUND

Complex regional pain syndrome (CRPS) is an orphan disease occurring as a complication after trauma. Due to its acute onset and the typical clinical presentation of the inflammatory and autonomous signs, it is an eye-catching chronic pain disease affecting also young and working people. In social media and the internet, high pain severity and unfavorable prognosis is often empathized.

METHODS

Here, we compared epidemiological, pain and lifestyle factors of 223 CPRS patients from the "ncRNAPain" cohort with 255 patients with chronic musculoskeletal pain (MSK). MSK patients were recruited at the beginning of a multimodal pain therapy program. We searched for factors predicting pain intensity.

RESULTS

Both chronic pain diseases affected women in middle age. Patients with MSK were more obese, drank more alcohol and were less educated (Pearson Chi-square Test or Mann-Whitney/U-Test). Both groups smoked more than healthy people in the OECD (Organization for Economic Cooperation and Development). Mann-Whitney/U-Test confirmed that CRPS patients did not have more severe pain and did not suffer more from pain-related disability than patients with MSK. CRPS patients also had less psychiatric comorbidities. Multiple linear regression analysis revealed that group assignment, depressive characteristics, body mass index, average alcohol consumption and smoking predicted higher pain ratings, while disease duration, anxiety symptoms or gender had no influence on pain intensity.

CONCLUSION

In summary our study supports a more optimistic view on pain in CRPS patients in comparison to MSK and identifies lifestyle factors which might contribute to the pathophysiology like smoking and drinking. Important next steps are the identification of CRPS patients at risk for chronification or - vice versa - with protective factors for pain resolution.