Complex Regional Pain Syndrome: A Comprehensive Review

Cognitive Multisensory Rehabilitation, a novel approach for Complex Regional Pain Syndrome: case series

INTRODUCTION

Effective treatment for Complex Regional Pain Syndrome (CRPS), a chronic pain condition, is challenging. Cognitive Multisensory Rehabilitation (CMR) is a cognitive and sensorimotor treatment approach aimed at restoring function that targets cognitive, somatosensory, and multisensory functions through sensory discrimination tasks.

PURPOSE

We aimed to apply CMR to treat CRPS within our clinical practice. Clinically, we have found promising results in reducing pain and other common features of CRPS, such as Body Perception Disturbances (BPD).

METHODS

In this clinical case series, four CRPS patients who participated in a two-week interdisciplinary CRPS rehabilitation program at the National Complex Regional Pain Syndrome Service in Bath, UK received CMR as part of their treatment. A combination of self-reported measures and clinical outcomes were collected pre and post-rehabilitation program.

RESULTS

Functional improvements and a reduction on BPD were observed in all clinical cases.

DISCUSSION

We demonstrate how CMR may improve several CRPS-related features that often hinder rehabilitation in people living with CRPS.

CONCLUSION

Research involving larger cohorts are necessary to provide empirical evidence of the application of CMR in treating CRPS.

Dermatologic manifestations of complex regional pain syndrome improved after dorsal root ganglion stimulation

Background

Complex regional pain syndrome is a condition that causes autonomic dysfunction, including severe pain, swelling, temperature fluctuations, and cutaneous flushing.

Case Description

The patient was a 38-year-old woman with complex regional pain syndrome type I of the right foot that developed after a work-related accident. At the time of presentation, she complained of a stabbing and burning pain, which subjectively felt like extreme warmth for 6 weeks. On physical examination, she presented with diffuse cutaneous flushing, erythema, nonpitting edema, skin mottling of the medial aspect of the right foot and ankle, a purple macule on the right inferomedial aspect of the great toe, and a purple patch on the inferomedial aspect of the heel. The patient underwent right-sided L5/S1 open dorsal root ganglion (DRG) stimulation under the care of neurological surgery. Postprocedurally, the cutaneous flushing, erythema, edema, mottling, purple macule, and patch had completely resolved. At the 1-year postoperative appointment, the patient continued to have a significant improvement in her preoperative pain and notably improved allodynia, flushing, mottling, and temperature sensitivity.

Conclusion

We have described the successful resolution of complex regional pain syndrome associated dermatologic manifestations in the setting of DRG stimulation. To our knowledge, a case of this nature has yet to be described in the literature.

The efficacy of an interdisciplinary pain management program for complex regional pain syndrome compared to low back pain and chronic widespread pain: an observational study

BACKGROUND

Little research has assessed the efficacy of interdisciplinary pain management programs (IPMPs) for complex regional pain syndrome (CRPS), whereas evidence shows that IPMPs are effective for low back pain (LBP) and chronic widespread pain (CWP). This study aimed to determine whether outcomes following an IPMP differ for people with CRPS compared to LBP and CWP. In addition, we determined whether it is possible to predict IPMP outcomes using baseline characteristics.

METHODS

People with CRPS (N = 66) who had completed a 3-week IPMP were compared with age- and gender- matched controls with LBP (N = 66) and CWP (N = 66). Measures of pain intensity, pain interference and psychological factors were extracted for pre- and post-program, and at 1, 6, and 12 months. Latent class analysis identified recovery trajectories for pain intensity and pain interference, and χ2 analyses assessed differences between diagnostic groups in recovery trajectories. Machine learning models were implemented to predict recovery trajectories from baseline scores.

RESULTS

Two recovery trajectories for each dependent variable (pain interference and for pain intensity) were identified: Good responders and poorer responders. Following IPMPs, 37% of people belonged to a good responder recovery trajectory for pain interference, and 11% belonged to a good responder recovery trajectory for pain intensity. Recovery trajectories were similar across the three diagnostic groups (CRPS, LBP, CWP) for pain interference (χ2 = 1.8, P = .4) and intensity (χ = 0.2, P = .9). Modeling to predict outcomes correctly classified 69% of cases for pain interference and 88% of cases for pain intensity recovery trajectories using baseline scores.

CONCLUSION

People with CRPS, LBP, and CWP experience similar benefits following an IPMP. This supports the use of IPMPs for people with CRPS.

Associated factors, triggers and long-term outcome in Complex Regional Pain Syndrome (CRPS) in the upper limb - A descriptive cross-sectional study

The pathophysiology behind Complex Regional Pain Syndrome (CRPS) is not fully understood and associated factors and triggers for developing the condition are debated. We aimed to study such factors and long-term outcome in a descriptive cross-sectional study with a well-defined population with CRPS in the upper limb and related to sex and CRPS type. In retrospectively collected data from medical records, 149 subjects [women n = 104 (70%); type 1 CRPS, n = 108 (72%); type 2 CRPS, n = 41 (28%); follow-up time 21 [8-43] months] were identified and analysed (Chi-squared test, Mann-Whitney U-test, and multiple linear regression). A majority were manual workers, and a larger proportion of subjects were smokers and had less post-secondary education than a reference population (p < 0.001 and p < 0.008). Men were younger, more frequently smoked, had higher BMI, and had lower education levels than women (p = 0.044, p = 0.007, p < 0.001, and p = 0.016, respectively). Subjects with CRPS type 2 were younger and had a longer time from symptoms until diagnosis, longer follow-up time, and more follow-up visits, indicating worse outcome (p = 0.016, p = 0.0012, p = 0.003, and p = 0.004, respectively). Among CRPS, 32% had a prior pain disorder and 7% had previously visited a pain management clinic. While there was no significant difference in mental illness occurrence before CRPS diagnosis compared to a reference population, mental illness increased by 76% after diagnosis. Factors such as CRPS type 2, older age, and delayed diagnosis were associated with longer follow-up periods. Additionally, 45% were on sick leave for over 12 months, and 20% were permanently unable to work. Socioeconomic deprivation is an associated factor in developing CRPS, in which a variety of triggers exist. Subjects with CRPS, particularly type 2, are at high risk of severe remaining symptoms, including mental illness and risk of never returning to work.

Effect of high-intensity laser therapy and mirror therapy on complex regional pain syndrome type I in the hand area: A randomized controlled trial

BACKGROUND

Complex regional pain syndrome type I (CRPS-I) is a painful condition with peripheral and central nervous system dysfunction, disproportionate inflammation, and the resultant muscle atrophy and restriction of motion. The use of high-intensity laser therapy (HILT) is being considered to reduce inflammation and neural and musculoskeletal pain. As maladaptive neuroplasticity occurs, peripheral treatment may not be enough and a combination of peripheral and centrally-focused interventions may be required.

PURPOSE

To explore the impact of HILT combined with mirror therapy (MT) on pain intensity, swelling, functional ability, range of motion (ROM), and electromyography (EMG) activity in CRPS-I.

STUDY DESIGN

Randomized, sham-controlled, single-blind clinical trial.

METHODS

Twenty-four CRPS-I patients were randomly assigned to two groups of HILT at 5 watts with an energy density of 20 J/cm², combined with MT and sham HILT and MT for six sessions. Pain was assessed by the Visual Analog Scale (VAS) before, the third session, and after the treatment. Hand swelling, function, and ROM were measured by a motion analysis system, and EMG of the hand muscles was also evaluated.

RESULTS

Pain significantly decreased in the HILT group. Compared to before treatment, the VAS mean difference in the third session was -2 ± 0.8 in the HILT group versus -0.4 ± 0.5 in the sham group (p < 0.001, ηp2 = 0.57). The VAS mean difference for before-after treatment was -4.2 ± 1.2 in the HILT group versus -1.4 ± 0.6 in the sham group (p < 0.001, ηp2 = 0.69). The other outcomes, like function, effusion, ROM, and EMG activity, were also in favor of the HILT group (p < 0.05).

CONCLUSIONS

Our study results offer conclusive evidence of pain reduction, a highly debilitating symptom in CRPS-I, even after the third HILT treatment session. Additionally, HILT effectively reduced swelling, improved performance, and enhanced muscle activity in CRPS-I.

MeCP2 Modulates Depression-Like Behaviors Comorbid to Chronic Pain by Regulating Adult Hippocampal Neurogenesis

AIMS

Although previous studies have revealed the association between chronic pain-induced depression and defective adult hippocampal neurogenesis (AHN), the underlying molecular mechanism remains elusive. This study aims to examine the association between AHN and depression-like behaviors, and to reveal the underlying mechanisms.

METHODS

The chronic neuropathic pain model was established using mice with the spared nerve injury (SNI) surgery. The depression-like behaviors were evaluated by using the sucrose preference test (SPT), the tail suspension test (TST), the forced swimming test (FST), and the open field test (OFT). The expression of Methyl-CpG-binding protein 2 (MeCP2) was modulated by injecting the adeno-associated virus (AAV) with the DIO system into the ventral DG of the Nes-CreERT2 mice. The miRNAs in hippocampal neural stem cells (NSCs) of mice with chronic pain were analyzed via miRNA sequencing.

RESULTS

We found that MeCP2, an epigenetic factor that plays a key role in the development of neurons, was significantly down-regulated in NSCs in the dentate gyrus (DG) of the hippocampus in adult mice with chronic pain and comorbid depression, suggesting a role of MeCP2 in the regulation of depression-like behavior induced by chronic neuropathic pain. MeCP2 expression levels in hippocampal NSCs were closely related to AHN and chronic pain comorbid depression, and miR-199b-3p specifically targeted and inhibited MeCP2 expression by directly interacting with its 3'-UTR sequence. Furthermore, we demonstrated that the increased level of miR-199b-3p in NSCs after the occurrence of chronic pain was responsible for AHN inhibition and comorbid depression.

CONCLUSION

Chronic neuropathic pain may result in an increased level of miR-199b-3p in hippocampal NSCs, which in turn targeted the Mecp2 gene and inhibited its transcription. Inhibited MeCP2 expression in NSCs contributes to AHN inhibition and depression-like behaviors.

Engrams across diseases: Different pathologies - unifying mechanisms?

Memories are our reservoir of knowledge and thus, are crucial for guiding decisions and defining our self. The physical correlate of a memory in the brain is termed an engram and since decades helps researchers to elucidate the intricate nature of our imprinted experiences and knowledge. Given the importance that memories have for our lives, their impairment can present a tremendous burden. In this review we aim to discuss engram malfunctioning across diseases, covering dementia-associated pathologies, epilepsy, chronic pain and psychiatric disorders. Current neuroscientific tools allow to witness the emergence and fate of engram cells and enable their manipulation. We further suggest that specific mechanisms of mnemonic malfunction can be derived from engram cell readouts. While depicting the way diseases act on the mnemonic component - specifically, on the cellular engram - we emphasize a differentiation between forms of amnesia and hypermnesia. Finally, we highlight commonalities and distinctions of engram impairments on the cellular level across diseases independent of their pathogenic origins and discuss prospective therapeutic measures.

How can Blood Flow Restriction Exercise be Utilised for the Management of Persistent Pain Following Complex Injuries in Military Personnel? A Narrative Review

BACKGROUND

Persistent pain is a complicated phenomenon associated with a wide array of complex pathologies and conditions (e.g., complex regional pain syndrome, non-freezing cold injury), leading to extensive disability and reduced physical function. Conventional resistance training is commonly contraindicated in load compromised and/or persistent pain populations, compromising rehabilitation progression and potentially leading to extensive pharmacological intervention, invasive procedures, and reduced occupational status. The management of persistent pain and utility of adjunct therapies has become a clinical and research priority within numerous healthcare settings, including defence medical services.

MAIN BODY

Blood flow restriction (BFR) exercise has demonstrated beneficial morphological and physiological adaptions in load-compromised populations, as well as being able to elicit acute hypoalgesia. The aims of this narrative review are to: (1) explore the use of BFR exercise to elicit hypoalgesia; (2) briefly review the mechanisms of BFR-induced hypoalgesia; (3) discuss potential implications and applications of BFR during the rehabilitation of complex conditions where persistent pain is the primary limiting factor to progress, within defence rehabilitation healthcare settings. The review found BFR application is a feasible intervention across numerous load-compromised clinical populations (e.g., post-surgical, post-traumatic osteoarthritis), and there is mechanistic rationale for use in persistent pain pathologies. Utilisation may also be pleiotropic in nature by ameliorating pathological changes while also modulating pain response. Numerous application methods (e.g., with aerobic exercise, passive application, or resistance training) allow practitioners to cater for specific limitations (e.g., passive, or contralateral application with kinesiophobia) in clinical populations. Additionally, the low-mechanical load nature of BFR exercise may allow for high-frequency use within residential military rehabilitation, providing a platform for conventional resistance training thereafter.

CONCLUSION

Future research needs to examine the differences in pain modulation between persistent pain and pain-free populations with BFR application, supporting the investigation of mechanisms for BFR-induced hypoalgesia, the dose-response relationship between BFR-exercise and pain modulation, and the efficacy and effectiveness of BFR application in complex musculoskeletal and persistent pain populations.

Current and Evolving Concepts in the Management of Complex Regional Pain Syndrome: A Narrative Review

Background/Objectives: Complex regional pain syndrome (CRPS) is characterized by severe pain and reduced functionality, which can significantly affect an individual's quality of life. The current treatment of CRPS is challenging. However, recent advances in diagnostic and treatment methods show promise for improving patient outcomes. This review aims to place the question of CRPS in a broader context and highlight the objectives of the research for future directions in the management of CRPS. Methods: This study involved a comprehensive literature review. Results: Research has identified three primary pathophysiological pathways that may explain the clinical variability observed in CRPS: inflammatory mechanisms, vasomotor dysfunction, and maladaptive neuroplasticity. Investigations into these pathways have spurred the development of novel diagnostic and treatment strategies focused on N-Methyl-D-aspartate Receptor Antagonists (NMDA), Toll-like receptor 4 (TLR-4), α1 and α2 adrenoreceptors, as well as the identification of microRNA (miRNA) biomarkers. Treatment methods being explored include immune and glial-modulating agents, intravenous immunoglobulin (IVIG) therapy, plasma exchange therapy, and neuromodulation techniques. Additionally, there is ongoing debate regarding the efficacy of other treatments, such as free radical scavengers, alpha-lipoic acid (ALA), dimethyl fumarate (DMF), adenosine monophosphate-activated protein kinase (AMPK) activators such as metformin, and phosphodiesterase-5 inhibitors such as tadalafil. Conclusions: The controversies surrounding the mechanisms, diagnosis, and treatment of CRPS have prompted researchers to investigate new approaches aimed at enhancing understanding and management of the condition, with the goal of alleviating symptoms and reducing associated disabilities.

[Cognitive behavioral therapy for complex regional pain syndrome]

Complex regional pain syndrome (CRPS) is often associated with severe mental impairments. Initial pain-related fears in particular appear to be negative predictors for long-term therapy results. Procedures for cognitive behavioral therapy are an important component of treatment. The psychotherapy of CRPS consists of various elements that are implemented in the different phases of treatment. In the beginning the focus is on targeted psychoeducation. In the following activation phase body awareness exercises are accompanied by occupational and physiotherapeutic treatment in order to improve the perception of individual maximum loads. Behavioral analyses are used to uncover dysfunctional coping patterns, such as a fear avoidance coping strategy. In this case the use of graded activity treatment approach is indicated, in which the activity level is gradually increased. In the transfer phase psychotherapy supports affected patients in (re)designing their professional and private environments.

Weathering the Pain: Ambient Temperature's Role in Chronic Pain Syndromes

PURPOSE OF REVIEW

Chronic pain is highly prevalent and involves a complex interaction of sensory, emotional, and cognitive processes, significantly influenced by ambient temperature. Despite advances in pain management, many patients continue to experience inadequate pain relief. This review aims to consolidate and critically evaluate the current evidence on the impact of ambient temperature on chronic pain conditions such as fibromyalgia (FM), multiple sclerosis (MS), complex regional pain syndrome (CRPS), and osteoarthritis (OA).

RECENT FINDINGS

Patients with FM often report pain exacerbations due to temperature changes, with studies showing lower thresholds for heat and cold-induced pain compared to healthy controls. In MS, the Uhthoff phenomenon, characterized by temperature-induced neurological deterioration, underscores the significance of ambient temperature in pain management. CRPS patients exhibit heightened pain sensitivity to temperature changes, with both warm and cold stimuli potentially aggravating symptoms. OA patients frequently report increased pain and rigidity associated with lower temperatures and higher humidity. Understanding the mechanisms through which temperature influences pain can enhance pain management strategies. This review highlights the need for further research to elucidate these mechanisms and develop targeted interventions, ultimately improving the quality of life for individuals with chronic pain conditions.

Ketamine Infusion for Complex Regional Pain Syndrome Treatment: A Narrative Review

PURPOSE OF REVIEW

Complex Regional Pain Syndrome (CRPS) is a neuropathic pain disorder characterized by pain disproportionate to the inciting event that is constant for an extended duration. Numerous treatment options for this condition have been explored with unsatisfactory results in many cases. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist typically used as an anesthetic and analgesic, presents a promising potential treatment for CRPS in patients who fail to respond to traditional therapies.

RECENT FINDINGS

Numerous studies report significant improvement in the degree of pain, mobility of extremities, and other parameters after ketamine infusion in patients with CRPS. Although adverse effects were not reported often, some subjects experienced nausea, vomiting, headache or psychotropic or psychomimetic symptoms which could be mitigated with cessation of the drug. Although more research is needed to determine optimal dosing and duration, ketamine seems to be a safe and effective treatment for refractory cases of CRPS.

CONCLUSION

The present investigation summarizes existing knowledge and research surrounding ketamine infusions for CRPS to provide a well-rounded depiction of advantages and disadvantages for physicians who may be considering it for patients with this challenging and complex condition.

Examining the effects of race/ethnicity and other factors on outcomes of care for complex regional pain syndrome type 1 in the United States

Complex regional pain syndrome is a chronic pain disorder marked by symptoms such as swelling, impaired motor function, and sympathetic dysfunction. Our primary objective was to determine the total number of complex regional pain syndrome type 1 (CRPS-1) emergency department (ED) visits and hospitalizations by race/ethnicity, as well as to assess sex and age distributions by race/ethnicity. Secondary objectives were to examine whether race/ethnicity, as well as select characteristics, are associated with hospitalization and longer length of stay. We completed a cross-sectional study of adults (19+ years) using acute and inpatient care data from the 2020 Nationwide Emergency Department Sample and the National Inpatient Sample. The overall rate of CRPS-1 diagnosis among ED visits and hospitalizations was 0.02% and 0.04%, respectively. Most CRPS-1 care was provided to White (ED: 83.1%; inpatient: 82.8%) patients. Within race/ethnicity groups, CRPS-1 ED visits and hospitalizations generally increased with age. Secondary findings included: 1) ED visits by Black individuals (compared with White) were significantly negatively associated with immediate hospitalization (adjusted odds ratio (AOR) 0.74, 95% CI 0.55 to 0.99); 2) hospitalizations by Black patients (compared with White) were independently associated with increased length of stay (odds ratio (OR) 1.45, 95% CI 1.07 to 1.96), though the association diminished with adjustment; and 3) drug abuse was significantly associated with hospitalization (AOR 4.67, 95% CI 3.53 to 6.18) and longer length of stay (AOR 1.81, 95% CI 1.34 to 2.46). Race/ethnicity was minimally associated with studied CRPS-1 outcomes. Additional studies are required to determine the impact of race/ethnicity on seeking care for CRPS-1.

Efficacy of Immunotherapy for Complex Regional Pain Syndrome: A Narrative Review

PURPOSE OF REVIEW

Complex regional pain syndrome (CRPS) is a chronic condition characterized by disproportional pain typically affecting an extremity. Management of CRPS is centered around specific symptomatology, which tends to be a combination of autonomic dysfunction, nociceptive sensitization, chronic inflammation, and/or motor dysfunction. Targeting the autoimmune component of CRPS provides a way to both symptomatically treat as well as minimize progression of CRPS.

RECENT FINDINGS

Understanding the physiology of CRPS and strategies for treating and targeting immunophysiology behind CRPS allows examination of the efficacy of such treatments. IL-1 receptor antagonism, glucocorticoid administration, IVIG infusion, and TNFα inhibitors are treatments that target the immune response and decrease inflammation, thereby reducing pain and enhancing function in patients with CRPS. IL-1 receptor antagonism is thought to inhibit the inflammatory effects of IL-1, a key player in the inflammatory process in CRPS. Glucocorticoids have anti-inflammatory properties and can reduce inflammation in affected tissues. IVIG infusion involves administering immunoglobulins, which may modulate the immune response and reduce autoimmunity in CRPS. TNFα inhibitors block the action of TNFα, a pro-inflammatory cytokine associated with CRPS development. These therapies are further discussed at the extent of mechanism of action as well as advantages and limitations of such therapies. The present investigation provides a detailed summary of the mechanism of action, advantages, and limitations of novel immunomodulatory therapies and recent studies and trials that investigated these therapies for CRPS. Future studies are warranted related to the role of immunomodulators in the treatment of CRPS.

The actual duration of spinal cord stimulator use in patients with complex regional pain syndrome: a Korean nationwide cohort study

Background

Spinal cord stimulators (SCSs) are used to reduce pain and improve quality of life in patients with complex regional pain syndrome (CRPS). However, many patients opt for device removal after SCS implantation due to diminished effect or complications. There is limited research on the actual duration of SCS use in CRPS patients, and no nationwide population-based studies exist. This study aimed to estimate the real-world duration of SCS use in CRPS patients and examine the influencing factors on the duration of SCS use by analyzing the National Healthcare Insurance Database.

Methods

Adult patients (age ≥ 18) with CRPS who underwent permanent SCS implantation between 2014 and 2021 were included. The authors analyzed the median duration of SCS implantation and evaluated the impacts of age, sex, hospital type, and insurance type.

Results

Of 408 potential patients, 373 patients were included. The median duration of SCS use was 4.4 (95% confidence interval [CI]: 4.0-4.8) years. Male patients retained SCSs longer than female patients (4.7 vs . 4.0 years, P = 0.014), and veterans' healthcare beneficiaries showed the longest duration of SCS use (median 6.9 [95% CI: 4.6-7.8] years). Age and hospital type did not affect the duration of SCS use (P = 0.381 and P = 0.122, respectively).

Conclusions

The median SCS use duration in CRPS patients was 4.4 years. Considering the high cost and invasiveness of SCS, patients should be informed about the expected duration of SCS use, alongside potential risks and benefits.

Timed-Release Silica Microcapsules for Consistent Fragrance Release in Topical Formulations

Microcapsules are widely utilized in various applications to preserve active ingredients for prolonged durations while enabling controlled release. However, limited release of active ingredients often hampers their effectiveness in daily-use products. In this study, we demonstrated the synthesis of silica core–shell microcapsules designed for controlled fragrance release in topical formulations. The microcapsules were synthesized via the sol–gel polymerization of tetraethyl orthosilicate (TEOS) on the surface of an oil/water emulsion, leveraging the shrinkage and deformation characteristics of sol–gel-derived silica during drying. The concentrations of dipalmitoylethyl dimethylammonium chloride, a cationic emulsifier used in cosmetics, and TEOS were optimized to sustain fragrance release for up to 24 h after topical application. An additional silica coating on the microcapsules reduced the Brunauer–Emmett–Teller surface area by 76.54%, enhancing fragrance stability for long-term storage. The timed-release behavior was assessed using fragrance evaluation tests and gas chromatography–mass spectrometry. The fragrance intensity and release profiles confirmed the potential of these microcapsules in daily-use cosmetics. These findings suggest that silica microcapsules with extended-release properties have application potential in both cosmetic and pharmaceutical products.

Spinal cord stimulation for the treatment of complex regional pain syndrome: A systematic review of randomized controlled trials

Background

Spinal Cord Stimulation (SCS) is a widely recognized treatment for Complex Regional Pain Syndrome (CRPS), particularly in cases where traditional methods are ineffective. This paper systematically reviews randomized controlled trials to analyze the efficacy of SCS, as well as Dorsal Root Ganglion (DRG) Stimulation in treating CRPS, focusing on its long-term effectiveness.

Methods

This systematic review focused exclusively on randomized controlled trials to assess a primary outcome of improvement in pain symptoms in patients diagnosed with CRPS. The primary outcomes assessed were pain reduction and patient satisfaction, with attention to functional improvement, quality of life improvement, preference for waveform settings, and complications when such data was made available.

Results

The results showed significant pain reduction in CRPS patients treated with SCS and DRG. Preference for specific SCS settings varied among patients, with no clear superiority of one setting over another. Innovations in SCS technology, including novel waveforms and frequencies, demonstrated potential for enhanced efficacy and patient comfort.

Conclusions

The review underscores the importance of SCS and DRG as significant treatment options to reduce pain for patients suffering from CRPS. It highlights the need for ongoing research to optimize SCS therapy, focusing on individual patient preferences and responses to different stimulation parameters. This personalized approach could lead to improved patient outcomes in CRPS management. Additionally, as this study only contained data from Randomized Controlled Trials, inclusion of well-conducted observational studies may help to provide stronger evidence for use of this therapy in CRPS patients.

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.

Complex Regional Pain Syndrome: Diagnosis, Pathophysiology, and Treatment Approaches

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by significant sensory, motor, and autonomic dysfunction, often following trauma or nerve injury. Historically known as causalgia and reflex sympathetic dystrophy, CRPS manifests as severe, disproportionate pain, often accompanied by hyperalgesia, allodynia, trophic changes, and motor impairments. Classified into type I (without nerve injury) and type II (associated with nerve damage), CRPS exhibits a complex pathophysiology involving peripheral and central sensitization, neurogenic inflammation, maladaptive brain plasticity, and potential autoimmune and psychological influences. The diagnosis relies primarily on clinical evaluation using criteria such as the Budapest Criteria, supported by supplementary tests to exclude differential diagnoses. However, its overlapping features with other conditions complicate diagnostic accuracy. The management of CRPS necessitates a multidisciplinary approach combining physical therapy, psychological support, and pharmacotherapy. Physical therapies, including graded motor imagery and mirror therapy, are essential for preserving function and preventing complications. Pharmacological treatments target neuropathic pain and inflammatory components, utilizing agents such as gabapentinoids, corticosteroids, and bisphosphonates. In refractory cases, interventional modalities like spinal cord stimulation and dorsal root ganglia stimulation provide promising options, although their efficacy remains variable. Emerging therapies, such as immune-modulatory treatments and advanced neuromodulation techniques, reflect the ongoing pursuit of effective interventions. This review synthesizes current knowledge, providing insights into diagnostic frameworks, pathophysiological mechanisms, and evolving treatment strategies to improve outcomes for individuals affected by CRPS.

Complete Improvement of Severe Forearm Complex Regional Pain Syndrome with Six High-Dose Incobotulinumtoxin A Injections: Clinical Implications with Respect to the Literature

There is some evidence that injections of botulinum neurotoxin effectively reduce pain in complex regional pain syndromes (CRPSs). But no or little experience appears to exist for the application of incobotulinum neurotoxin type A (incoBoNT/A) in complex pain disorders. Here, a case of CRPS type I, characterized by severe symptoms in the left forearm is presented, showed significant continuous improvement following a series of six repetitive (painful) injections into the finger, hand, and forearm muscles of incoBoNT/A every 3 months, administered at declining doses varying between 500 and 100 U. Remarkably, this treatment regimen led to the complete resolution of pain, vaso- and sudomotor symptoms, and hand dystonia. This highlights the possible efficacy of incoBoNT/A in the treatment of CRPS and encourages the further exploration of incoBoNT/A's role in the successful management of complex pain disorders.

Benign Evolution of Complex Regional Pain Syndrome (CRPS) Type 1 in Patients Treated with Intravenous Neridronate: A Single-Center Real-Life Experience

OBJECTIVE

To investigate the long-term effects of intravenous neridronate treatment in patients with complex regional pain syndrome type 1 (CRPS) in a real-life setting.

METHODS

We conducted a retrospective study on consecutive CRPS patients treated at our hospital from February 2018 to July 2023. All were treated within three months of the onset of CRPS symptoms. The Patient-Reported Outcomes Measurement Information System 29-Item Health Profile (PROMIS-29) version 2.1 was administered. The main outcome of interest was the evolution of the PROMIS-29 scores from baseline to the last follow-up visit. Patients were categorized as "complete responders" or "non-complete responders". The association of clinical and demographic variables with a complete response was analyzed using chi-square tests and univariate logistic regression.

RESULTS

Thirty-six patients were included, with a median follow-up time of 4.8 years. A significant improvement was noted in the mean numerical pain rating scale (from 6.4 ± 1.9 to 3.1 ± 2.4, p < 0.001), as well as across all PROMIS-29 domains. Physical function improved from 34.2 ± 4.9 to 49.2 ± 9.9, p < 0.001; anxiety from 58.0 ± 6.7 to 49.6 ± 6.9, p < 0.001; depression from 55.3 ± 6.3 to 47.7 ± 6.6, p < 0.001; fatigue from 55.7 ± 7.7 to 50.9 ± 8.7, p < 0.001; sleep disturbance from 53.8 ± 6.8 to 51.3 ± 6.6, p = 0.034; social roles and activities from 41.8 ± 5.2 to 51.8 ± 8.9, p < 0.001; and pain interference from 64.1 ± 5.9 to 52.4 ± 9.9, p < 0.001. The likelihood of achieving a complete response was associated with the male sex, foot or ankle injuries (compared to hand and wrist injuries), and a younger age. No association was found with the type of inciting event or with the body mass index.

CONCLUSIONS

Our real-life data indicate that early treatment with neridronate leads to substantial benefits in patients affected by CRPS type 1. The strongest responses are seen in young patients, males, and those with lower limb involvement.

Chronic post-ischemic pain (CPIP) a model of complex regional pain syndrome (CRPS-I): Role of oxidative stress and inflammation

Complex regional pain syndrome (CRPS) presents as a persistent and distressing pain condition often stemming from limb trauma or ischemia, manifesting as either CRPS-I (without initial nerve injury) or CRPS-II (accompanied by nerve injury). Despite its prevalence and significant impact on functionality and emotional well-being, standard treatments for CRPS remain elusive. The multifaceted nature of CRPS complicates the identification of its underlying mechanisms. In efforts to elucidate these mechanisms, researchers have turned to animal models such as chronic post-ischemic pain (CPIP), which mirrors the symptoms of CRPS-I. Various mechanisms have been proposed to underlie the acute and chronic pain experienced in CRPS-I, including oxidative stress and inflammation. Traditional treatment approaches often involve antidepressants, non-steroidal anti-inflammatory drugs (NSAIDs), and opioids. However, these methods frequently fall short of providing adequate relief. Accordingly, there is a growing interest in exploring alternative treatments, such as antioxidant supplementation, anti-inflammatory agents, and non-pharmacological interventions. Future research directions should focus on optimizing treatment strategies and addressing remaining gaps in knowledge to improve patient outcomes. This review aims to delve into the pathophysiological mechanisms implicated in the CPIP model, specifically focusing on oxidative stress and inflammation, with the ultimate goal of proposing innovative therapeutic strategies for alleviating the symptoms of CRPS-I.

Intraoperative Pain Management for Treatment-Resistant Complex Regional Pain Syndrome: A Case Report

Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder often following trauma, associated with severe pain and autonomic disturbances in the affected limbs. Managing CRPS is challenging due to the lack of FDA-approved medications, often requiring off-label treatments. Traditional options like nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids show limited efficacy, while adjunctive treatments such as gabapentin, antidepressants, and bisphosphonates are increasingly favored. Surgical interventions, including nerve blocks and spinal cord stimulation, may help in refractory cases but have varying success rates. Recent discussions highlight intraoperative ketamine, which targets N-methyl-D-aspartate (NMDA) pathways linked to CRPS. This case study illustrates the complexity of CRPS management, particularly how psychosocial factors and secondary trauma can exacerbate or alleviate symptoms. The case centers on a treatment-resistant flare-up of CRPS, managed through revision neurolysis of the sciatic, tibial, and perineal nerves, along with the release of the right tibial nerve and intraoperative ketamine. Trauma's impact is evident, as the patient initially went into remission after nerve decompression, only for symptoms to return severely following a subsequent trauma. This emphasizes the need for a multipronged treatment approach. Intraoperative ketamine provides rapid pain relief during and after surgery, benefiting patients with severe chronic pain while reducing post-surgery opioid needs and minimizing dependency risks. Patients typically achieve improved functional recovery and better rehabilitation engagement. Research suggests ketamine may offer long-lasting pain relief and psychological benefits, positively impacting mood and anxiety.

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.

Chemokine CXCL13-CXCR5 signaling in neuroinflammation and pathogenesis of chronic pain and neurological diseases

Chronic pain dramatically affects life qualities of the sufferers. It has posed a heavy burden to both patients and the health care system. However, the current treatments for chronic pain are usually insufficient and cause many unwanted side effects. Chemokine C-X-C motif ligand 13 (CXCL13), formerly recognized as a B cell chemokine, binds with the cognate receptor CXCR5, a G-protein-coupled receptor (GPCR), to participate in immune cell recruitments and immune modulations. Recent studies further demonstrated that CXCL13-CXCR5 signaling is implicated in chronic pain via promoting neuroimmune interaction and neuroinflammation in the sensory system. In addition, some latest work also pointed out the involvement of CXCL13-CXCR5 in the pathogenesis of certain neurological diseases, including ischemic stroke and amyotrophic lateral sclerosis. Therefore, we aim to outline the recent findings in regard to the involvement of CXCL13-CXCR5 signaling in chronic pain as well as certain neurological diseases, with the focus on how this chemokine signaling contributes to the pathogenesis of these neurological diseases via regulating neuroimmune interaction and neuroinflammation. Strategies that can specifically target CXCL13-CXCR5 signaling in distinct locations may provide new therapeutic options for these neurological diseases.

Efficacy of manual lymphatic drainage combined with repetitive transcranial magnetic stimulation in post-stroke complex regional pain syndrome: a pilot study

PURPOSE

The aim of this study was to investigate the efficacy of manual lymphatic drainage (MLD) combined with repetitive transcranial magnetic stimulation (rTMS) on the recovery of upper limb in patients with post-stroke complex regional pain syndrome (CRPS).

METHODS

This pilot study was conducted with 54 patients with post-stroke CRPS. Patients were randomized into three groups: the MLD combined with rTMS group (MLD + rTMS group), the rTMS group and the sham-rTMS group. The results of numeric rating scale (NRS), volumetric measurement, Fugl-Meyer assessment of upper extremity (FMA-UE), CRPS severity score (CSS), generalized anxiety disorder-7 (GAD-7) and patient health questionnaire-9 (PHQ-9) before and after the intervention were analyzed.

RESULTS

Fifty-four participants (37 males, 17 females; mean age 66.11 ± 8.43 years; range, 18 to 85) were included in the study. Among groups, improvements were statistically significant with superiority of rTMS + MLD group after treatment (p < 0.05). NRS, GAD-7, and PHQ-9 in the rTMS + MLD group improved more significantly than those in the rTMS group (p < 0.05).

CONCLUSION

MLD combined with rTMS has an add-on efficacy on the basis of rTMS therapy in post-stroke patients, especially in pain. MLD could also have an effect on anxiety and depression.

Fever associated with machine activation after sacral neuromodulation: Case report

INTRODUCTION AND IMPORTANCE

Sacral neuromodulation (SNM) is commonly used in the treatment of refractory overactive bladder (OAB), non-obstructive urinary retention (NOR) and fecal incontinence. Here, we report an atypical symptomatic case to enrich the limited international case series.

CASE PRESENTATION

We report a case of a male patient with cauda equina nerve injury left over from a traumatic injury and dysfunction of urinary and fecal functions who, after undergoing phase I sacral nerve stimulator placement, developed fever when the machine was switched on, and the symptoms resolved when it was switched off.

CLINICAL DISCUSSION

Sacral neuromodulation (SNM) is commonly used in the treatment of refractory overactive bladder (OAB), non-obstructive urinary retention (NOR) and fecal incontinence. The patient did not develop a non-infectious fever after the injury, only after the SNM device was installed and activated, and the temperature returned to normal after shutdown. We hypothesize that on top of the patient's pre-existing nerve damage and disorders, the activation of the SNM somehow stimulated the relevant sites, causing the patient to develop a neurogenic fever.

CONCLUSION

We concluded that in this case, it is reasonable to consider that the patient's fever was closely related to the placement of the sacral nerve stimulator.

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 Widespread Pain

OBJECTIVE

This article reviews the potential etiologies of chronic widespread pain syndromes and outlines a practical approach to the management of patients with these disorders.

LATEST DEVELOPMENTS

Recent updates to diagnostic criteria for primary chronic widespread pain syndromes have allowed for more effective diagnosis. Fibromyalgia is the most common presentation of chronic widespread pain, and the concept of nociplastic pain has been used to describe pain that is related to altered processing of pain sensory pathways. Research studies have provided a better understanding of the pathophysiology of the central augmentation that occurs in patients with nociplastic pain and fibromyalgia.

ESSENTIAL POINTS

Primary chronic widespread pain and fibromyalgia have established diagnostic criteria in which chronic pain involves multiple defined regions and occurs for longer than 3 months. Evaluation of chronic widespread pain should be directed by the clinical presentation. Neurologic disease can present with chronic widespread pain but is accompanied by associated signs and symptoms. Patients with chronic widespread pain benefit from effective communication that validates concerns, provides an understandable explanation of the presenting symptoms, and sets realistic expectations in outcomes using a comprehensive multimodal care plan.

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.

Effects of Stress Exposure to Pain Perception in Pre-Clinical Studies: Focus on the Nociceptin/Orphanin FQ-NOP Receptor System

Exposure to physical and psychological stress modulates pain transmission in a dual manner. Stress-induced analgesia (SIA) refers to the reduction in pain sensitivity that can occur in response to acute stress. On the contrary, chronic stress exposure may lead to a phenomenon named stress-induced hyperalgesia (SIH). SIH is a clinically relevant phenomenon since it has been well documented that physical and psychological stress exacerbates pain in patients with several chronic pain syndromes, including migraine. The availability of animal models of SIA and SIH is of high importance for understanding the biological mechanisms leading to these phenomena and for the identification of pharmacological targets useful to alleviate the burden of stress-exacerbated chronic pain. Among these targets, the nociceptin/orphanin FQ (N/OFQ)-N/OFQ peptide (NOP) receptor system has been identified as a key modulator of both pain transmission and stress susceptibility. This review describes first the experimental approaches to induce SIA and SIH in rodents. The second part of the manuscript summarizes the scientific evidence that suggests the N/OFQ-NOP receptor system as a player in the stress-pain interaction and candidates NOP antagonists as useful drugs to mitigate the detrimental effects of stress exposure on pain perception.

Sensors and Devices Guided by Artificial Intelligence for Personalized Pain Medicine

Personalized pain medicine aims to tailor pain treatment strategies for the specific needs and characteristics of an individual patient, holding the potential for improving treatment outcomes, reducing side effects, and enhancing patient satisfaction. Despite existing pain markers and treatments, challenges remain in understanding, detecting, and treating complex pain conditions. Here, we review recent engineering efforts in developing various sensors and devices for addressing challenges in the personalized treatment of pain. We summarize the basics of pain pathology and introduce various sensors and devices for pain monitoring, assessment, and relief. We also discuss advancements taking advantage of rapidly developing medical artificial intelligence (AI), such as AI-based analgesia devices, wearable sensors, and healthcare systems. We believe that these innovative technologies may lead to more precise and responsive personalized medicine, greatly improved patient quality of life, increased efficiency of medical systems, and reducing the incidence of addiction and substance use disorders.

Concurrent Chronic Exertional Compartment Syndrome and Popliteal Artery Entrapment Syndrome

Exertional leg pain occurs with notable frequency among athletes and poses diagnostic challenges to clinicians due to overlapping symptomatology. In this case report, we delineate the clinical presentation of a young collegiate soccer player who endured two years of progressive bilateral exertional calf pain and ankle weakness during athletic activity. The initial assessment yielded a diagnosis of chronic exertional compartment syndrome (CECS), predicated on the results of compartment testing. However, her clinical presentation was suspicious for concurrent type VI popliteal artery entrapment syndrome (PAES), prompting further radiographic testing of magnetic resonance angiography (MRA). MRA revealed severe arterial spasm with plantarflexion bilaterally, corroborating the additional diagnosis of PEAS. Given the worsening symptoms, the patient underwent open popliteal entrapment release of the right leg. Although CECS and PAES are both known phenomena that are observed in collegiate athletes, their co-occurrence is uncommon owing to their different pathophysiological underpinnings. This case underscores the importance for clinicians to be aware that the successful diagnosis of one condition does not exclude the possibility of a secondary, unrelated pathology. This case also highlights the importance of dynamic imaging modalities, including point-of-care ultrasound, dynamic MRA, and dynamic angiogram.

The Treatment of Chronic Complex Regional Pain Syndrome with Novel Neuromodulatory Sound Waves: A Case Report

This paper presents a case of a 35-year-old female patient diagnosed with Complex Regional Pain Syndrome (CRPS) type I and treated over a two-month period with a novel low-frequency sound-transduced focal pulsed stimulus. The patient received 21 treatments consisting of focally applied sound sweeps in the 15-100 Hz range. Outcome measures included the Visual Analogue Scale for pain, five physical assessment parameters, medication, and the Pain Catastrophizing Scale. A follow-up was conducted at six months. The results show that the patient's low-back pain level was substantially reduced after treatment and after six months. CRPS-related peripheral pain was strongly reduced but had some rebound after six months. The low-frequency sound-transduced focal pulsed stimulus shows potential as a non-invasive treatment for CRPS and deserves controlled clinical trials.

Enkephalins and Pain Modulation: Mechanisms of Action and Therapeutic Perspectives

Enkephalins, a subclass of endogenous opioid peptides, play a pivotal role in pain modulation. Enkephalins primarily exert their effects through opioid receptors located widely throughout both the central and peripheral nervous systems. This review will explore the mechanisms by which enkephalins produce analgesia, emotional regulation, neuroprotection, and other physiological effects. Furthermore, this review will analyze the involvement of enkephalins in the modulation of different pathologies characterized by severe pain. Understanding the complex role of enkephalins in pain processing provides valuable insight into potential therapeutic strategies for managing pain disorders.

Does Platelet-Rich Plasma Deserve a Role in Accelerating the Recovery of Reflex Sympathetic Dystrophy Following Distal Radius Fracture?

Introduction

This study was to evaluate the efficacy of multiple platelet-rich plasma injections in reflex sympathetic dystrophy following distal radius fracture after previous various treatments have failed.

Materials and methods

This comparative prospective study was designed for 64 patients of reflex sympathetic dystrophy developed following distal radius fracture, from January 2009 to December 2020 were enrolled in this study. This cohort of patient was given either four multiple subcutaneous platelet-rich plasma injections at weekly interval (n = 32) or two injections in a month with 15 days interval (n = 32). The primary outcome measure assessed with patient rated wrist evaluation questionnaire score. The secondary outcome was a visual analogue scale pain score. The final follow up was at 2 years. p ≤ 0.05 is considered statistically.

Results

The patient rated wrist evaluation score for usual and specific activities and EQ-VAS for pain level showed statistically significant greater improvement in group A (42 ± 21%) compared to group B (19 ± 24%), (p = 0.37). Patients also had improvement in wrist movements with no statistically significant differences in both groups. The standard difference in means of all three functional scores was almost similar between both groups A and B (standard difference in means = 0.032; 95% CI 0.236-0.830; p = 0.495), considered clinically meaningful.

Conclusion

This study results suggest autologous platelet-rich plasma injections seem to be safe, cost effective, efficacious algorithm treatment for reflex sympathetic dystrophy following distal radius fracture patients where previous treatments have failed.

Beyond Confirmed Mast Cell Activation Syndrome: Approaching Patients With Dysautonomia and Related Conditions

Allergist-immunologists face significant challenges as experts in an ever-evolving field of neuroimmunology. Among these challenges is the increasingly frequent need to counsel patients with suspected mast cell activation disorders about perceived comorbidities, which may include hypermobile Ehlers-Danlos syndrome, amplified pain syndrome, fibromyalgia, burning sensation syndromes, migraines, irritable bowel syndrome, and postural orthostatic tachycardia syndrome. Patients may experience comorbid anxiety, panic disorder, and depression associated with disturbed sleep, fatigue, and cognitive impairment that often worsen when their physical symptoms increase in severity. These conditions may mimic mast cell activation disorders and are emotionally taxing for patients and clinicians because they are often accompanied by vague diagnostic courses, perceived unmanageability, social stigma, and significant impairment in quality of life. Combined with relatively poorly researched therapies, it is no surprise that clinicians may feel overwhelmed or find it difficult to provide consistently compassionate care for this population. In this article, we review available therapies for these conditions, which run the gamut from physical therapy to antidepressants to multimodal pain control. We highlight the benefit of multidisciplinary care within the primary care home, which includes an important role by the allergist-immunologist. By outlining simple approaches to initial treatment, we hope to empower clinicians with the tools needed to curb emotional burnout and embrace this patient population with compassion.

Analgesic Effect of SKI306X on Chronic Postischemic Pain and Spinal Nerve Ligation-Induced Neuropathic Pain in Mice

Neuropathic pain (NP) results from lesions or diseases affecting the peripheral or central somatosensory system. However, there are currently no drugs that are particularly effective in treating this condition. SKI306X is a blend of purified extracts of three oriental herbs (Clematis mandshurica, Trichosanthes kirilowii, and Prunella vulgaris) commonly used to treat osteoarthritis for their chondroprotective effects. Chronic postischemic pain (CPIP) and spinal nerve ligation (SNL) models were created by binding the upper left ankle of mice with an O-ring for 3 h and ligating the L5 spinal nerve, respectively. Mice with allodynia were injected intraperitoneally with 0.9% normal saline (NS group) or different doses (25, 50, or 100 mg/kg) of SKI306X (SKI groups). We assessed allodynia using von Frey filaments before injection and 30, 60, 90, 120, 180, and 240 min and 24 h after injection to confirm the antiallodynic effect of SKI306X. We also measured glial fibrillary acidic protein (GFAP) levels in the spinal cord and dorsal root ganglia to confirm the change of SKI306X administration. Both models exhibited significant mechanical allodynia. The intraperitoneal injection of SKI306X significantly increased the paw withdrawal threshold in a dose-dependent manner, as the paw withdrawal threshold was significantly increased after SKI306X administration compared with at baseline or after NS administration. GFAP levels in the SKI group decreased significantly (p < 0.05). Intraperitoneal administration of SKI306X dose-dependently attenuated mechanical allodynia and decreased GFAP levels, suggesting that GFAP is involved in the antiallodynic effect of SKI306X in mice with CPIP and SNL-induced NP.

Efficacy and Safety of Pharmacological Treatment in Patients with Complex Regional Pain Syndrome: A Systematic Review and Meta-Analysis

Complex regional pain syndrome (CRPS) is a disabling condition that usually affects the extremities after trauma or surgery. At present, there is no FDA-approved pharmacological treatment for patients with CRPS. We performed this systematic review and meta-analysis to evaluate the efficacy and safety of pharmacological therapies and determine the best strategy for CRPS. We searched the databases, including PubMed, Embase, Cochrane, Web of Science, Scopus, and ClinicalTrials.gov, for published eligible randomized controlled trials (RCTs) comparing pharmacological treatment with placebo in CRPS patients. Target patients were diagnosed with CRPS according to Budapest Criteria in 2012 or the 1994 consensus-based IASP CRPS criteria. Finally, 23 RCTs comprising 1029 patients were included. We used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to rate certainty (confidence in evidence and quality of evidence). Direct meta-analysis showed that using bisphosphonates (BPs) (mean difference [MD] -2.21, 95% CI -4.36--0.06, p = 0.04, moderate certainty) or ketamine (mean difference [MD] -0.78, 95% CI -1.51--0.05, p = 0.04, low certainty) could provide long-term (beyond one month) pain relief. However, there was no statistically significant difference in the efficacy of short-term pain relief. Ketamine (rank p = 0.55) and BPs (rank p = 0.61) appeared to be the best strategies for CRPS pain relief. Additionally, BPs (risk ratio [RR] = 1.86, 95% CI 1.34-2.57, p < 0.01, moderate certainty) and ketamine (risk ratio [RR] = 3.45, 95% CI 1.79-6.65, p < 0.01, moderate certainty) caused more adverse events, which were mild, and no special intervention was required. In summary, among pharmacological interventions, ketamine and bisphosphonate injection seemed to be the best treatment for CRPS without severe adverse events.

Analysis of Surgical Procedures on the Forearm and Hand and Their Relationship with Complex Regional Pain Syndrome: A Cross-sectional Study

Objective  Complex regional pain syndrome (CRPS) requires further understanding. Thus, the present study aimed to analyze if pre- and intraoperative factors may be related to the development of CRPS in the postoperative period. Methods  We reviewed 1,183 medical records of patients undergoing forearm and hand surgeries from 2015 to 2021. The data of interest, that is, diagnosis, incisions, synthesis material, and anesthesia, were collected, tabulated, and statistically analyzed, with subsequent calculation of the odds ratios. Results  Most patients were female, aged between 30 and 59 years, and sought the service electively (67% of the cases). The diagnoses included soft tissue trauma (43%), bone trauma (31.6%), and compressive syndromes (25.5%). During this period, 45 (3.8%) subjects developed CRPS. The statistical analysis showed that the chance of developing CRPS is twice as high in patients with compressive syndrome, especially carpal tunnel syndrome (CTS), which represented most surgeries performed in our service (24%). Two or more incisions occurred in 7.6% of the cases, which tripled the chance of developing postoperative CRPS. Gender, age, use pf synthetic material, type of anesthesia type did not statistically increase the risk of developing postoperative CRPS. Conclusion  In short, the incidence of CRPS is low; however, it is critical to know and recognize the risk factors for prevention and active screening in the postoperative period.

Postoperative Medial Plantar and Sural Neuropathy With Complex Regional Pain Syndrome

This case illustrates a distinct presentation of coexistent medial plantar and sural neuropathy leading to the development of complex regional pain syndrome (CRPS) in a 49-year-old male patient. CRPS is a broad medical diagnosis describing prolonged and excessive pain that is out of proportion to exam and has historically been diagnosed according to the Budapest criteria. To our knowledge, this is a rare report of a case of medial plantar and sural neuropathy further complicated with CRPS, status-post calcaneal fracture, surgery, and post-surgical boot placement. The case highlights the complexity of diagnosing and managing multiple concurrent neuropathies and underscores the need for interdisciplinary approaches in treating CRPS to improve patient outcomes.

Neuropathic pain in burn patients - A common problem with little literature: A systematic review

BACKGROUND

The prevalence of neuropathic pain (NP) in burn patients is reported in the literature to be as high as 80%1. Given the complexity of NP in burn patients and the wide range of treatments available, a systematic review of the literature is warranted to summarize our current understanding of management and treatment of NP in this population.

METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The following databases were queried to identify relevant articles: PubMed, Cochrane, Embase, Scopus, Ovid, and Web of Science. The main outcome measures were incidence and management of NP. Secondary outcomes included risk factors for NP.

RESULTS

Included articles presented findings from 11 different countries, capturing outcomes for 4366 patients. Risk factors for neuropathic pain in burn patients were identified, including older age, alcohol and substance abuse, current daily smoking, greater % total body surface area burns (TBSA), and longer hospitalizations. Pharmacologic treatments included gabapentin/pregabalin (n = 7), ascorbic acid (n = 1), and lidocaine (n = 1). Overall, the studies showed varied results regarding the efficacy of pharmacological treatments. While certain studies demonstrated gabapentanoids to be effective in reducing neuropathic symptoms, others found conflicting results. With regards to non-pharmacologic treatments, electroconvulsive therapy (n = 1), electropuncture (n = 1), nerve release/reconstruction (n = 2), and somatosensory feedback rehabilitation (n = 1) were used and demonstrated promise in reducing pain intensity and improving functionality.

CONCLUSIONS

Despite NP afflicting the majority of burn patients long after their injury, this systematic review demonstrates insufficient evidence on the pathophysiology, outcomes, and risk factors in NP, as well as the efficacy of various therapies. Future prospective and randomized studies evaluating the etiology of these factors can substantially improve our treatment strategies. This can allow for the development of well-delineated and evidence-based protocols in NP management in hopes of improving quality of life and both psychological and physical function in burn patients.

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.

Permanent Peripheral Nerve Stimulator for Complex Regional Pain Syndrome of the Forearm and Hand

A 51-year-old woman with diabetes and depression was referred to the anesthesia pain clinic with a 15-year history of complex regional pain syndrome type I of the right forearm and hand in the radial sensory nerve distribution. There was no recognized antecedent trauma and she had failed both medical treatment and radial sensory nerve decompression surgery. An ultrasound-guided local anesthetic block of the radial nerve in the upper arm resulted in partial and temporary improvement in pain. She subsequently underwent trial of a peripheral nerve stimulator (PNS) followed by permanent PNS implant placement over the radial nerve proper proximal to the elbow. Within the first month of use, she endorsed substantially improved pain and strength in her right hand. These improvements were sustained for more than 1 year. Applications of PNS technology for treatment of extremity complex regional pain syndrome and neuropathic extremity pain in general are reviewed.

Causalgia: A Review of Nerve Resection, Amputation, Immunotherapy, and Amputated Limb CRPS II Pathology

BACKGROUND

Causalgia and complex regional pain syndrome (CRPS) type II with nerve injury can be difficult to treat. Surgical peripheral nerve denervation for causalgia has been largely abandoned by pain clinicians because of a perception that this may aggravate a central component (anesthesia dolorosa).

METHODS

We selectively searched Pubmed, Cochrane, MEDLINE, EMBASE, CINAHL Plus, and Scopus from 1947 for articles, books, and book chapters for evidence of surgical treatments (nerve resection and amputation) and treatment related to autoimmunity and immune deficiency with CRPS.

RESULTS

Reviews were found for the treatment of causalgia or CRPS type II (n = 6), causalgia relieved by nerve resection (n = 6), and causalgia and CRPS II treated by amputation (n = 8). Twelve reports were found of autoimmunity with CRPS, one paper of these on associated immune deficiency and autoimmunity, and two were chosen for discussion regarding treatment with immunoglobulin and one by plasma exchange. We document a report of a detailed and unique pathological examination of a CRPS type II affected amputated limb and related successful treatment with immunoglobulin.

CONCLUSIONS

Nerve resection, with grafting, and relocation may relieve uncomplicated causalgia and CRPS type II in some patients in the long term. However, an unrecognized and treatable immunological condition may underly some CRPS II cases and can lead to the ultimate failure of surgical treatments.

Complex regional pain syndrome: diagnostic challenges and favorable response to prednisolone

Complex regional pain syndrome (CRPS), characterized by severe and disproportionate pain, is a rare and debilitating condition. Due to its rarity, evidence-based treatment guidelines remain limited, creating a challenge for clinicians. We present the case of a 20-year-old female with CRPS type 1 of the right hand. Her pain, initially triggered by a minor trauma, had persisted for three months. The patient demonstrated severe pain, swelling, hyperesthesia, and restricted range of motion. Despite multiple hospital visits, her symptoms did not improve until she was diagnosed with CRPS and treated with oral prednisolone. A dosage of 40 mg daily led to a dramatic response within 10 days. Our report emphasizes the importance of recognizing CRPS and highlights the potential of prednisolone as a treatment option, particularly in resource-limited settings, where more specialized interventions may be unavailable. Further research is essential to establish a stronger evidence base for the use of steroids in CRPS management.

The effectiveness of graded motor imagery and its components on phantom limb pain in amputated patients: A systematic review

BACKGROUND

Phantom limb pain (PLP) can be defined as pain in a missing part of the limb. It is reported in 50%-80% of people with amputation.

OBJECTIVES

To provide an overview of the effectiveness of graded motor imagery (GMI) and the techniques which form it on PLP in amputees.

STUDY DESIGN

Systematic review.

METHODS

Two authors independently selected relevant studies, screened the articles for methodological validity and risk of bias, and extracted the data. Inclusion criteria used were clinical studies, written in English or Spanish, using GMI, laterality recognition, motor imagery, mirror therapy, or a combination of some of them as an intervention in amputated patients, and one of the outcomes was PLP, and it was assessed using a validated scale. The databases used were PubMed, Scopus, Web of Science, CINAHL, and PEDro.

RESULTS

Fifteen studies were included in the review. After the intervention, all the groups in which the GMI or one of the techniques that comprise it was used showed decrease in PLP.

CONCLUSION

The 3 GMI techniques showed effectiveness in decreasing PLP in amputees, although it should be noted that the application of the GMI showed better results.

Mirror visual feedback as therapeutic modality in unilateral upper extremity complex regional pain syndrome type I: randomized controlled trial

BACKGROUND

There is growing evidence for the effectiveness of mirror therapy (MT) on pain reduction in patients with type I complex regional pain syndrome (CRPS I).

AIM

To evaluate the efficacy of MT on pain reduction and hand function in subjects with unilateral upper extremity CRPS I.

DESIGN

Randomized controlled trial with control group cross-over (half cross-over design).

SETTING

Subjects with CRPS I were outpatients of a university hospital and cooperating centers. All patients carried out the daily exercise at home.

POPULATION

Subjects with unilateral upper extremity CRPS I meeting the Budapest diagnostic criteria.

METHODS

Subjects were randomly divided into two groups. Group A (N.=13) carried out a ten-minute MT exercise daily, for a total duration of six weeks. Group B (N.=14) acted as a control group for six weeks followed by six weeks of MT with the same characteristics as Group A. Upper extremity active range of motion, strength, dexterity, limb volume, affected-to-unaffected hand temperature difference, and health-related quality of life were evaluated before and after each period. Daily records on the visual analogue scale were used for pain evaluation. Effectiveness was calculated using mixed-effects modelling for between-group comparisons and within-group variability, and identification of significant predictors.

RESULTS

Twenty-three females and four males with an average age of 56.1±9.6 years completed the study. Except for the affected-to-unaffected hand temperature difference, both groups consistently demonstrated significant or near-significant improvements in measured parameters after MT period. The improvements were evident upon an intergroup comparison of Group A and the control period of Group B as well as longitudinally within Group B. No significant improvement was found during the control period.

CONCLUSIONS

Principles focused on mirror visual feedback to the central nervous system can sustain promising therapeutic potential as part of the treatment for pain reduction and hand function in CRPS I patients.

CLINICAL REHABILITATION IMPACT

MT can be considered as part of the therapeutic regimen employed for the treatment of CRPS I.

Contact-Heat Evoked Potentials: Insights into Pain Processing in CRPS Type I

Purpose

The pathophysiological mechanisms underlying the development of chronic pain in complex regional pain syndrome (CRPS) are diverse and involve both peripheral and central changes in pain processing, such as sensitization of the nociceptive system. The aim of this study was to objectively distinguish the specific changes occurring at both peripheral and central levels in nociceptive processing in individuals with chronic CRPS type I.

Patients and Methods

Nineteen individuals with chronic CRPS type I and 16 age- and sex-matched healthy controls (HC) were recruited. All individuals underwent a clinical examination and pain assessment in the most painful limb, the contralateral limb, and a pain-free control area to distinguish between peripheral and central mechanisms. Contact-heat evoked potentials (CHEPs) were recorded after heat stimulation of the three different areas and amplitudes and latencies were analyzed. Additionally, quantitative sensory testing (QST) was performed in all three areas.

Results

Compared to HC, CHEP amplitudes in CRPS were only increased after stimulation of the painful area (p=0.025), while no increases were observed for the pain-free control area (p=0.14). None of the CHEP latencies were different between the two cohorts (all p>0.23). Furthermore, individuals with CRPS showed higher pain ratings after stimulation of the painful limb compared to their contralateral limb (p=0.013). Lastly, compared to HC, mechanical (p=0.012) and thermal (p=0.046) sensitivity was higher in the painful area of the CRPS cohort.

Conclusion

This study provides neurophysiological evidence supporting an intact thermo-nociceptive pathway with signs of peripheral sensitization, such as hyperexcitable primary afferent nociceptors, in individuals with CRPS type I. This is further supported by the observation of mechanical and thermal gain of sensation only in the painful limb. Additionally, the increased CHEP amplitudes might be related to fear-induced alterations of nociceptive processing.

Teriparatide and clodronate combination as a potential treatment for complex regional pain syndrome type I in delayed consolidation after foot surgery: a case report and review of the literature

BACKGROUND

Complex regional pain syndrome type I is a pathological condition characterized by an exaggerated response of tissues to low or moderate pain stimuli. The exact pathogenesis and optimal medical treatment for complex regional pain syndrome type I are still not fully understood, although bisphosphonates have shown positive effects in reducing pain. Foot surgery can be complicated by the development of complex regional pain syndrome type I, leading to functional decline and difficulties in weight-bearing.

CASE PRESENTATION

The authors present a clinical case involving complex regional pain syndrome type I that developed after surgical foot arthrodesis. The patient, a 42-year-old Caucasian male, did not respond to clodronate treatment but experienced successful outcomes upon the addition of teriparatide, which effectively stimulated the healing of arthrodesis.

CONCLUSION

Teriparatide cannot be considered the primary treatment for complex regional pain syndrome due to insufficient solid clinical data. However, when complex regional pain syndrome is associated with or caused by delayed union, teriparatide can be used to address the underlying cause of complex regional pain syndrome.