Complex Regional Pain Syndrome: Current Diagnostic and Treatment Considerations

Complex Regional Pain Syndrome: Evidence-Based Advances in Concepts and Treatments

PURPOSE OF REVIEW

This review presents the most current information about the epidemiology of complex regional pain syndrome (CRPS), classification and diagnostic criteria, childhood CRPS, subtypes, pathophysiology, conventional and less conventional treatments, and preventive strategies.

RECENT FINDINGS

CRPS is a painful disorder with multifactorial pathophysiology. The data describe sensitization of the central and peripheral nervous systems, inflammation, possible genetic factors, sympatho-afferent coupling, autoimmunity, and mental health factors as contributors to the syndrome. In addition to conventional subtypes (type I and type II), cluster analyses have uncovered other proposed subtypes. Prevalence of CRPS is approximately 1.2%, female gender is consistently associated with a higher risk of development, and substantial physical, emotional, and financial costs can result from the syndrome. Children with CRPS seem to benefit from multifaceted physical therapy leading to a high percentage of symptom-free patients. The best available evidence along with standard clinical practice supports pharmacological agents, physical and occupational therapy, sympathetic blocks for engaging physical restoration, steroids for acute CRPS, neuromodulation, ketamine, and intrathecal baclofen as therapeutic approaches. There are many emerging treatments that can be considered as a part of individualized, patient-centered care. Vitamin C may be preventive. CRPS can lead to progressively painful sensory and vascular changes, edema, limb weakness, and trophic disturbances, all of which substantially erode healthy living. Despite some progress in research, more comprehensive basic science investigation is needed to clarify the molecular mechanisms of the disease so that targeted treatments can be developed for better outcomes. Incorporating a variety of standard therapies with different modes of action may offer the most effective analgesia. Introducing less conventional approaches may also be helpful when traditional treatments fail to provide sufficient improvement.

Efficacy of stellate ganglion interventions for complex regional pain syndrome in the upper limb-A systematic review and meta-analysis

Background and Aims

Stellate ganglion (SG) interventions for treating upper limb complex regional pain syndrome (CRPS) have been reported in studies. However, more substantial evidence is required to reach a consensus on its analgesic efficacy. To the best of our knowledge, no systematic review demonstrating the effectiveness of SG intervention for upper limb CRPS has been reported. Hence, this meta-analysis was done to ascertain the efficacy of SG intervention in managing patients with upper limb CRPS.

Methods

A database search of PubMed, Cochrane, Embase, Scopus and Google Scholar was done for articles published between January 2001 and December 2021. Two independent reviewers extracted data from the included studies, and the studies were evaluated for any potential risk of bias, and a meta-analysis was performed.

Results

Eight studies were included in the qualitative synthesis, four were randomised controlled trials (RCTs), and the rest were non-RCTs. Six studies were assessed quantitatively. A significant reduction in pain scores post-intervention, up to two weeks, and four to 28 weeks after the procedure was observed, although the included studies exhibited marked heterogeneity. Qualitative analysis of these studies revealed an overall improvement in disability scores and functionality as assessed by an improved range of motion. Most studies reported no complications or only short-term minor complications after the procedure.

Conclusion

Stellate ganglion interventions improve pain and disability scores with self-limiting short-term complications and no long-term complications. However, further studies with a large sample size are required to validate this treatment modality.

Complex Regional Pain Syndrome: Is There a Role for Capsaicin?

Complex regional pain syndrome (CRPS) is a challenging disorder occurring in patients most often after trauma or surgery. Its treatment is very complex, and even then, no treatment is fully effective. Capsaicin is a well-accepted treatment for neuropathic pain. However, its use in CRPS is controversial, with few studies having been published on it. In this case report, we describe the case of a female patient with CPRS type II, whose treatment with topical capsaicin resulted in great functional improvement. The patient was referred to the Pain Medicine Unit due to a CRPS type II due to trauma in her right wrist. She complained of severe pain in the median nerve territory of her dominant hand, associated with hyperalgesia, allodynia, burning, and electric shock sensation, resulting in functional disability. Electromyography was compatible with severe axonal injury of the right median nerve of the wrist. After conventional therapies were tried with no improvement, treatment with a capsaicin 8% patch was proposed. A functional improvement was observed after two applications of the capsaicin treatment, allowing the patient to regain activity in her hand. This shows that although evidence for capsaicin use in CRPS treatment is scarce, it can be a viable alternative for some patients.

[Lived Experience of Middle-Aged Patients with Complex Regional Pain Syndrome]

PURPOSE

This qualitative study aimed to explore the lived and true meaning of experiences of middle-aged patients with complex regional pain syndrome.

METHODS

The participants were 10 men and women aged 40 to 60 years who received outpatient treatment at a university hospital, could communicate, and agreed to participate in the study. Data were collected through individual interviews using open and semi-structured questions from September 2019 to July 2021 and were analyzed using the content analysis method suggested by Hsieh and Shannon (2005).

RESULTS

As a result of this study, 42 summarized semantic units related to life experience, 15 subthemes, and seven themes were derived. The seven themes were "pressed by severe pain," "frustrated because I cannot be part of the community," "distressed because people do not recognize my disease," "sad about conflicts with family," "unmotivated because of desperate life," "appreciating for support," and "putting oneself together and living daily life."

CONCLUSION

The vivid experiences of the participants derived in this study are the basic data for developing treatment guidelines. In the future, we propose a study on life and family care experiences according to the developmental characteristics of the life cycle of patients with complex regional pain syndrome and develop and apply programs to support patients and their families.

What Did We Learn About Fracture Pain from Animal Models?

Progress in bone fracture repair research has been made possible due to the development of reproducible models of fracture in rodents with more clinically relevant fracture fixation, where there is considerably better assessment of the factors that affect fracture healing and/or novel therapeutics. However, chronic or persistent pain is one of the worst, longest-lasting and most difficult symptoms to manage after fracture repair, and an ongoing challenge remains for animal welfare as limited information exists regarding pain scoring and management in these rodent fracture models. This failure of adequate pre-clinical pain assessment following osteotomy in the rodent population may not only subject the animal to severe pain states but may also affect the outcome of the bone healing study. Animal models to study pain were also mainly developed in rodents, and there is increasing validation of fracture and pain models to quantitatively evaluate fracture pain and to study the factors that generate and maintain fracture pain and develop new therapies for treating fracture pain. This review aims to discuss the different animal models for fracture pain research and characterize what can be learned from using animal models of fracture regarding behavioral pain states and new molecular targets for future management of these behaviors.

Complex Regional Pain Syndrome in Athletes: Scoping Review

Background and Objectives: Complex regional pain syndrome (CRPS) is a chronic condition characterized by disproportionate regional pain, usually affecting distal limbs, that follows trauma or surgery. Athletes may develop CRPS because of exposure to traumatic or overuse injuries. The aim of the present study is to review the available literature about CRPS type 1 in athletes. Materials and Methods: We searched two online databases (PubMed and Web of Science), selecting papers aiming at investigating CRPS type 1 (algodystrophy) in athletes. The analysis of databases was made considering original articles published until 30 June 2021, written in English. Results: Fifteen papers (12 case reports, 3 case series) were selected for a total of 20 clinical cases (15 females, 5 males), aged between 10 and 46 years (mean age 18.4 ± 9.8 standard deviation years). Patients included practiced different types of sport (soccer, athletics, gymnastics, basketball). The most involved anatomical sites were lower limbs, and time to diagnosis ranged from 2 days to 4 years. The most used treatments were pharmacological and physical therapies, but sometimes invasive approaches, as regional nerve, or lumbar sympathetic blocks, were provided. The main assessed outcomes were return to activity and pain. Conclusions: Our review suggests a higher prevalence of CRPS type 1 in younger people and in lower limbs than in general population but confirms the higher prevalence in females. However, the number of studies addressing CRPS in athletes is limited, as well as the number of involved patients, considering that only few and heterogeneous case reports were published about this topic. Moreover, the high prevalence of old studies (only 5 available studies in the last 10 years) might have influenced the choice of both assessment tools and management strategies. Despite these limitations, athletes showing disproportionate pain after sport-related injury should be promptly evaluated and treated through a multidimensional approach to avoid long-term consequences of algodystrophy.

Multicenter survey of symptoms, work life, economic status, and quality of life of complex regional pain syndrome patients

Background

Complex regional pain syndrome (CRPS) is an intractable pain disease with various symptoms. Here, we investigated the disease status, work life, sleep problems, medical insurance, economic status, psychological problems, and quality of life (QOL) of CRPS patients.

Methods

CRPS patients from 37 university hospitals in South Korea were surveyed. The survey questionnaire consisted of 24 questions on the following aspects of CRPS patients sex, age, occupation, cause of injury, activities of daily living (ADL), pain severity, sleep disturbance, level of education, economic status, therapeutic effect, and suicidal ideation. Additionally, the abbreviated World Health Organization Quality of Life (WHOQOL-BREF) questionnaire, consisting of 26 questions, was used to identify the status of QOL.

Results

A total of 251 patients completed the questionnaire. According to the survey, 54.2% patients could not perform ADL on their own. Over the previous week, the mean pain score was 7.15 ± 1.78 (out of a total of 10 points); 92.1% of patients had sleep disorders and 80.5% had suicidal ideation, with most patients suffering from psychological problems. The average for each domain of WHOQOL-BREF was as follows 21.74 ± 14.77 for physical, 25.22 ± 17.66 for psychological, 32.02 ± 22.36 for social relationship, and 30.69 ± 15.83 for environmental (out of a total of 100 points each). Occupation, ADL, sleep time, therapeutic effect, and suicidal ideation were statistically correlated with multiple domains.

Conclusions

Most patients had moderate to severe pain, economic problems, limitations of their ADL, sleep problems, psychological problems, and a low QOL score.

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

Conservative management of anterior cutaneous nerve entrapment syndrome: A case report

OBJECTIVE

To describe a conservative approach to care of an adult patient presenting with chronic abdominal wall pain persisting two years following abdominal surgery.

CLINICAL FEATURES

A 62-year-old female presented to a chiropractic neurologist with abdominal wall pain and sensation deficits. Her prior surgical history and a positive Carnett's sign indicated anterior cutaneous nerve entrapment syndrome (ACNES).

INTERVENTION AND OUTCOME

Treatments, including manual therapy, rehabilitation, and desensitization techniques, significantly reduced the frequency and severity of the ACNES symptoms.

CONCLUSION

ACNES can be effectively managed via nonsurgical and non-pharmacological treatment methods.

The Role of Nonmedical Therapeutic Approaches in the Rehabilitation of Complex Regional Pain Syndrome

Purpose of the Review

Nonmedical therapeutic approaches are fundamental to the management of of Complex Regional Pain Syndrome (CRPS) in order to promote the best outcome for patients. This review focuses on three key approaches underpinning CRPS rehabilitation, namely, physiotherapy and occupational therapy, psychological approaches and education and self-management.

Recent Findings

Recently published European standards outline the quality of therapeutic care that people with CRPS must receive. Early initiated therapy is essential to optimise outcomes, underpinned by patient education. Therapists should promote early movement of the affected limb and encourage re-engagement with usual activities as immobilisation is known to have negative outcomes. There is evidence to support the possible long-term benefit of graded motor imagery and mirror therapy. Psychological assessment should include identification of depression and post-traumatic stress disorder, as treatment of these conditions may improve the trajectory of CRPS. Novel therapies include neurocognitive approaches and those addressing spatial bias, both of which should provide a focus for future research.

Summary

There exists a broad range of nonmedical therapeutic approaches to rehabilitation for CPRS that are thought to be important. However, the evidence for their efficacy is limited. Further research using standardised outcomes would be helpful in developing targeted therapies for the future.