Reflex sympathetic dystrophy: changing concepts and taxonomy

Unveiling the anxiolytic and analgesic effects of citronellal in Swiss mice: in vivo and in silico insights into COX and GABAA receptor pathways

This study aims to evaluate the analgesic and anxiolytic effects of citronellal (CTL) in Swiss mice using two new sensitive and economic mouse models along with possible molecular mechanisms through in silico studies. For this, we employed marble displacement and spiked-field apparatus to check the anxiolytic and analgesic effects, respectively. In silico studies were done against cyclooxygenase (COX) enzymes and GABAA receptor subunits. Findings suggest that the test sample CTL significantly reduced the number of marbles displaces (NMD), square crosses (NSC), paw massages (NPM), and escaping attempts (NEA) in animals than the control group. CTL exhibited better effects in the perforated-field study compared to the reference drug diclofenac sodium. In both cases, CTL (200 mg/kg) significantly reduced the test parameters when combined with the standard drugs (diazepam or diclofenac sodium). In in silico studies, CTL showed binding affinities of - 5.5, - 5.2, - 4.8, and - 4.8 kcal/mol with the COX1, COX2, and GABAA receptors (α2 and α3 subunits), respectively. Taken together, CTL may exert anxiolytic- analgesic-like effects on mice, possibly through the GABAA receptor and COXs interaction pathways. These new tools might be used to check the anxiolytic and analgesic properties of a wide variety of test substances.

10. Complex regional pain syndrome

INTRODUCTION

Complex regional pain syndrome (CRPS) is a clinical disorder that can develop following surgery or trauma. Based on the most prominent underlying pathophysiological mechanisms, CRPS can be classified into different subtypes, namely inflammatory, nociplastic/neuropathic, vasomotor, and motor. Depending on the subtype, personalized treatment can be applied. If conservative treatments are insufficient or ineffective, more invasive treatments may be recommended. This article provides an overview of the most recent insights into CRPS and discusses the most common invasive treatments.

METHODS

The literature regarding interventional treatments for CRPS has been systematically reviewed and summarized.

RESULTS

Bisphosphonates are effective in treating the inflammatory subtype, while ketamine can provide pain relief for the nociplastic/neuropathic subtype. Sympathetic blocks are effective in addressing vasomotor disturbances. For patients with refractory symptoms, neurostimulation is a viable option due to its multimechanistic properties for all subtypes. End-of-line motor disturbances may benefit from intrathecal baclofen.

CONCLUSIONS

CRPS is a debilitating condition with an unpredictable course. The effectiveness of treatment varies from patient to patient. When conservative approaches prove insufficient, gradual progression to invasive treatments based on the underlying subtype is recommended.

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.

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

Background

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

Objective

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

Design

This is real-life retrospective observational study.

Methods

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

Results

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

Conclusions

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

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.

Bone Turnover Markers and Wnt Signaling Modulators in Early Complex Regional Pain Syndrome. A Pre-specified Observational Study

To explore serum levels of some bone turnover markers and the involvement of the Wnt signaling in CRPS-1. Query ID="Q1" Text="Please check and confirm whether the edit made to the article title is in order." We conducted an observational study on patients with early CRPS-1 recruited before any treatment. Clinical measures were assessed together with biochemical evaluation. Values of sclerostin, DKK1, CTX-I, and P1NP were compared with sex-age-matched healthy controls (HCs). We enrolled 34 patients diagnosed with CRPS-1 (mean age 59.3 ± 10.6 years, Male/Female 10/24), median disease duration = 2 weeks (IQR 1-5); median VAS score = 76 (IQR 68-80). Foot localization was slightly more frequent than hand localization (18/16). No statistically significant difference was found between CRPS-1 patients and HCs for CTX-I (0.3 ± 0.1 ng/ml vs 0.3 ± 0.1, p = 0.140), while mean serum values of P1NP were significantly higher in CRPS-1 patients compared to HCs (70.0 ± 38.8 ng/ml vs 50.1 ± 13.6, p = 0.005). Mean levels of sclerostin and DKK1 were lower in CRPS-1 patients vs HCs (sclerostin 28.4 ± 10.8 pmol/l vs 34.1 ± 11.6, p = 0.004; DKK1 12.9 ± 10.8 pmol/l vs 24.1 ± 11.9, p = 0.001). No statistically significant difference was found for all biochemical assessments in a subgroup of fracture-induced CRPS-1. No statistically significant differences were observed according to disease localization, disease duration, presence of hyperalgesia, allodynia, sudomotor alterations, and mild or moderate/severe swelling. No significant correlation emerged between sclerostin, DKK1 levels, baseline VAS score, or McGill Pain Questionnaire score. Bone involvement in early CRPS-1 does not seem to rely on increased osteoclast activity. Conversely, a serum marker of bone formation resulted increased. Both Sclerostin and DKK1 showed decreased values, probably suggesting a widespread osteocyte loss of function.Trial registration number: Eudract Number: 2014-001156-28.

Evaluation of anti-nociceptive and anti-inflammatory activities of solvent fraction of the roots of Echinops kebericho Mesfin (Asteraceae) in mice model

OBJECTIVE

The present study was aimed at investigating the antinociceptive and anti-inflammatory activities of the solvent fractions of the roots of Echinops kebericho Mesfin in rodent models of pain and inflammation.

METHODS

Successive maceration was used as a method of extraction using solvents of increasing polarity: methanol and water. Ethyl acetate, chloroform and distilled water were used as solvents of the fraction process. Swiss albino mice models were used in acetic acid induced writhing, hot plate, carrageenan induced paw edema and cotton pellet granuloma to assess the analgesic and anti-inflammatory activities. The test groups received different doses (100 mg/kg, 200 mg/kg and 400 mg/kg) of the three fractions (chloroform, ethyl acetate and aqueous). The positive control groups received ASA (150 mg/kg) for the writing test, morphine (10 mg/kg) for the hot plate method, diclofenac Na for carrageenan-induced paw edema, and dexamethasone (10 mg/kg) for granuloma, while the negative control group received distilled water.

RESULTS

EA fraction at all test doses employed (100 mg/kg, 200 mg/kg, and 400 mg/kg) showed statistically significant (p<0.05, p<0.01, p<0.001 respectively) analgesic and anti-inflammatory activities in a dose-dependent manner. The AQ fraction on the other hand produced statistically significant (p<0.05, p<0.012) analgesic and anti-inflammatory activities at the doses of 200 mg/kg and 400 mg/kg, while the CH fraction exhibited statistically significant (p<0.05) analgesic and anti-inflammatory activity at the dose of 400 mg/kg.

CONCLUSIONS

In general, the data obtained from the present study elucidated that the solvent fractions of the study plant possessed significant analgesic and anti-inflammatory activities and were recommended for further investigations.

Impact of different CRPS phenotypes and diagnostic criteria on quantitative sensory testing outcomes: systematic review and meta-analysis

OBJECTIVES

This review and meta-analysis evaluated the impact of diagnostic criteria and clinical phenotypes on quantitative sensory testing (QST) outcomes in patients with complex regional pain syndrome (CRPS).

METHODS

Eight databases were searched based on a previously published protocol. Forty studies comparing QST outcomes between CRPS-I vs II, warm vs cold CRPS, upper vs lower limb CRPS, males vs females, or using Budapest vs older IASP criteria were included.

RESULTS

Studies investigating QST differences between CRPS-I vs II (n = 4), between males vs females (n = 2), and between upper and lower limb CRPS (n = 2) showed no significant differences. Four studies compared QST outcomes in warm vs cold CRPS, showing heat hyperalgesia in warm CRPS, with thermal and mechanical sensory loss in cold CRPS. Although CRPS diagnosed using the Budapest criteria (24 studies) vs 1994 IASP criteria (13 studies) showed similar sensory profiles, there was significant heterogeneity and low quality of evidence in the latter.

CONCLUSIONS

Based on the findings of this review, classifying CRPS according to presence or absence of nerve lesion into CRPS-I and II, location (upper or lower limb) or according to sex might not be clinically relevant as all appear to have comparable sensory profiles that might suggest similar underlying mechanisms. In contrast, warm vs cold phenotypes exhibited clear differences in their associated QST sensory profiles. To the extent that differences in underlying mechanisms might lead to differential treatment responsiveness, it appears unlikely that CRPS-I vs II, CRPS location, or patient sex would prove useful in guiding clinical management.

Complex Regional Pain Syndrome-like Pattern in a Case of Pancoast Tumor

We present the case of a 52-year-old male who was recently diagnosed case of a Pancoast tumor and presented to the pulmonary outpatient department with a complaint of pain in the shoulder and chest region which was burning type, associated with shoulder abduction weakness and poor hand grip. Subsequently, he was referred for a 99m-Tc bone scan for metastatic workup, which showed increased uptake in all the joints and long bones of the ipsilateral upper limb. This case highlights the importance of considering nontraumatic cause of pattern similar to complex regional pain syndrome.

In Vivo, In Vitro and In Silico Study of Cucurbita moschata Flower Extract: A Promising Source of Natural Analgesic, Anti-Inflammatory, and Antibacterial Agents

For thousands of years, medicinal plants have played a pivotal role in maintaining human health and improving the quality of human life. This study was designed to analyze the analgesic, anti-inflammatory, and antibacterial potentials of a hydro-methanolic extract of Cucurbita moschata flowers, along with qualitative and quantitative phytochemical screening. The anti-inflammatory effect was tested using the in vitro membrane stabilizing method for human red blood cells (HRBC), the analgesic effect was tested using the in vivo acetic acid-induced writing method, and the antibacterial effect was tested using the disc diffusion method. In silico ADME/T and molecular docking studies were performed to assess the potential of the stated phytochemicals against Cyclooxygenase-II enzyme. Phytochemical screening confirmed the presence of flavonoids, alkaloids, glycosides, tannins, and carbohydrates. The flower extract demonstrated the maximum protection of human red blood cells at 1000 µg/mL, with a 65.73% reduction in hemolysis in a hypotonic solution. The extract also showed significant (p < 0.05) and dose-dependent analgesic effects at oral doses of 200 and 400 mg/kg on the tested animals. Furthermore, the flower extract exhibited potent antibacterial activity due to the disc diffusion method, which was compared with standard ciprofloxacin. In silico testing revealed that 42 phytochemicals exhibited notable pharmacokinetic properties and passed drug likeness screening tests. Among the six best-selected compounds, 3,4-dihydro-2H-pyran-2-yl)methanamine showed the highest binding affinity (-10.1) with significant non-bonding interactions with the target enzyme. In conclusion, the hydro-methanolic extract of Cucurbita moschata was found to be rich in various phytochemicals that may be associated with therapeutic potential, and this study supports the traditional use of Cucurbita moschata flowers in the management of inflammation and painful conditions.

Incidence and risk factors for complex regional pain syndrome in radius fractures: meta-analysis

PURPOSE

This meta-analysis aimed to evaluate the incidence and risk factors for complex regional pain syndrome (CRPS) in radius fractures.

METHODS

The meta-analysis was performed using the PubMed, Embase, Scopus, and Cochrane Collaboration Library databases. Studies focusing on patients with conservative or surgically treated radius fractures leading to CRPS were included. A control group consisting of patients with radius fractures and no CRPS (-) was included. The outcome measures were incidence and risk factors. Comparative studies were also included. Data were combined using Review Manager 5.4.

RESULTS

Out of 610 studies, nine studies were included. The incidence of CRPS after radius fractures ranged from 0.19 to 13.63% (95% CI: 11.12-16.15%). Open fractures, high-energy mechanisms in radial head fractures, and associations with ulnar fractures were risk factors for CRPS [(RR: 0.98; 95% CI: 0.97-1.00), (RR: 0.18; 95% CI: 0.07-0.47), and (RR: 1.25; 95% CI: 1.17-1.35), respectively]. Other risk factors were female sex and high body mass index [(RR: 1.20; 95% CI: 1.05-1.37) and (MD: 1.17; 95% CI: 0.45-1.88)]. Psychiatric factors also increased the incidence of CRPS (RR: 2.04; 95% CI: 1.83-2.28). On the other hand, the type of surgery (external fixation or open reduction and internal fixation) and manipulations; associated comorbidities (diabetes and hypertension) together with tobacco and alcohol abuse; marital status, educational level, employment status, and socioeconomic status were not risk factors (p > 0.05).

CONCLUSION

The incidence of CRPS in radius fractures was 13.63%. Fractures with greater complexity or greater associated tissue damage, female sex, high BMI, and psychiatric disorders were risk factors for the development of CRPS.

LEVEL OF EVIDENCE

Meta-analysis of cohort and case series studies; II.

Morphological and electrophysiological evaluation of median and ulnar nerve in complex regional pain syndrome type 1

OBJECTIVE

Complex regional pain syndrome (CRPS) can be distinguished as type I without and type II with electrophysiological evidence of major nerve lesion. The pathophysiology of both subgroups is still under investigation. The aim of this research is to demonstrate the nerve morphology and electrophysiology in CRPS type I patients.

MATERIALS AND METHODS

Bilateral median and ulnar nerve cross-sectional areas were evaluated with ultrasound and also median and ulnar nerve conduction studies of both hands were performed. Cross-sectional areas of median and ulnar nerves and nerve conduction studies in healthy controls were also obtained and compared with the patients.

RESULTS

Twenty-five male patients and 11 healthy male controls were enrolled in the study. The mean age of the patients was 24.08 ± 5.50 years and controls was 23.18 ± 5.09 (p > 0.05). Compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the diseased side were found significantly lower than the healthy side (p < 0.05). Both median and ulnar nerve distal motor latency values were significantly higher in the patient group (p < 0.05). There was no significant difference in the median and ulnar nerve cross-sectional area when compared with the opposite extremity and healthy volunteers.

CONCLUSION

The lower SNAP and CMAP amplitudes of the median and ulnar nerves compared to the healthy side and the prolongation of the affected side median and ulnar nerve distal motor latencies of the affected individuals may indicate axonal involvement in patients with CRPS type 1. Decreased CMAP amplitudes may also indicate muscle atrophy due to a decrease in the number of functional motor units.

Analgesic and Anti-Inflammatory Activities of 80% Methanol Extract and Solvent Fractions of Ehretia cymosa Thonn (Boraginaceae) Leaves in Rodents

Background

Ethnobotanical studies in various districts of Ethiopia reported that Ehretia cymosa (E. cymosa) is used for the management of headache, abdominal pain, arthritis and rheumatism. However, there is no scientific investigation done so far to confirm these traditional claims. Thus, the aim of this study was to assess the analgesic and anti-inflammatory effects of the 80% methanol extract and fractions of E. cymosa leaves.

Methods

The dried and pulverized leaves of E. cymosa were soaked with 80% methanol to obtain a crude extract. Fractionation was done using chloroform, ethyl acetate and water by a soxhlet apparatus. The analgesic effects of the crude extract and solvent fractions were assessed using acetic acid-induced writhing and hot plate tests whereas anti-inflammatory activities were investigated using carrageenan-induced paw edema and cotton-pellet-induced granuloma models.

Results

In all the tested doses, the 80% methanol extract and solvent fractions revealed substantial (p < 0.001) analgesic activities in acetic acid induced writhing test. In the hot plate method, all the tested doses of E. cymosa crude extract and the solvent fractions produced significant analgesic activities (p < 0.05). In the carrageenan-induced acute inflammation model, all tested doses of the crude extract and solvent fractions resulted in a significant decline in paw edema. The 80% methanol extract and solvent fractions of E. cymosa at all the tested doses significantly reduced inflammatory exudates and granuloma mass formations (p < 0.001).

Conclusion

From the results of this investigation, it can be stated that 80% methanol extract, aqueous, ethyl acetate and chloroform fractions of E. cymosa exhibited considerable analgesic and anti-inflammatory activities, supporting the plant's traditional use as a remedy for a variety of painful and inflammatory conditions.

Pain mechanisms in complex regional pain syndrome: a systematic review and meta-analysis of quantitative sensory testing outcomes

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic condition following inciting events such as fractures or surgeries with sensorimotor and autonomic manifestations and poor prognosis. This review aimed to provide conclusive evidence about the sensory phenotype of CRPS based on quantitative sensory testing (QST) to understand the underlying pain mechanisms and guide treatment strategies.

DATABASES

Eight databases were searched based on a previously published protocol. Forty studies comparing QST outcomes (thermal, mechanical, vibration, and electric detection thresholds, thermal, mechanical, pressure, and electric pain thresholds, wind-up ratio, mechanical pain sensitivity, allodynia, flare area, area after pinprick hyperalgesia, pleasantness after C-tactile stimulation, and pain ratings) in chronic CRPS (adults and children) versus healthy controls were included.

RESULTS

From 37 studies (14 of low quality, 22 of fair quality, and 1 of good quality), adults with CRPS showed: (i) significant loss of thermal, mechanical, and vibration sensations, significant gain of thermal and mechanical pain thresholds, significant elevation of pain ratings, and no difference in wind-up ratio; (ii) significant reduction of pleasantness levels and increased area of pinprick hyperalgesia, in the affected limb. From three fair-quality studies, adolescents and children with CRPS showed loss of cold detection with cold hyperalgesia in the affected limb. There was moderate to substantial overall heterogeneity.

CONCLUSION

Diffuse thermal and mechanical hypoesthesia with primary and secondary hyperalgesia, enhanced pain facilitation evidenced by increased area of pinprick hyperalgesia, and elevated pain ratings are dominant in adults with CRPS. Adolescents and children with CRPS showed less severe sensory abnormalities.

Complex Regional Pain Syndrome after Spine Surgery: A Rare Complication in Mini-Invasive Lumbar Spine Surgery: An Updated Comprehensive Review

BACKGROUND

Complex regional pain syndrome (CRPS) is a postoperative, misdiagnosed condition highlighted only by pain therapists after numerous failed attempts at pain control by the treating surgeon in the case of prolonged pain after surgery. It only occurs rarely after spine surgery, causing the neurosurgeon's inappropriate decision to resort to a second surgical treatment.

METHODS

We performed a systematic review of the literature reporting and analyzing all recognized and reported cases of CRPS in patients undergoing spinal surgery to identify the best diagnostic and therapeutic strategies for this unusual condition. We compare our experience with the cases reported through a review of the literature.

RESULTS

We retrieve 20 articles. Most of the papers are clinical cases showing the disorder's rarity after spine surgery. Most of the time, the syndrome followed uncomplicated lumbar spine surgery involving one segment. The most proposed therapy was chemical sympathectomy and spinal cord stimulation.

CONCLUSION

CRPS is a rare pathology and is rarer after spine surgery. However, it is quite an invalidating disorder. Early therapy and resolution, however, require a rapid diagnosis of the syndrome. In our opinion, since CRPS occurs relatively rarely following spinal surgery, it should not have a substantial impact on the indications for and timing of these operations. Therefore, it is essential to diagnose this rare occurrence and treat it promptly and appropriately.

Clinical practice guidelines for the management of patients with chronic regional pain syndrome: a systematic appraisal using the AGREE II instrument

Aim: Chronic regional pain syndrome (CRPS) is a debilitating, painful condition of limbs that often arises after an injury and is associated with significant morbidity. Materials & methods: The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument, used to assess the quality of clinical practice guidelines (CPGs), was used to evaluate seven CRPS management guideline. Results: Out of the seven CPGs evaluated using the AGREE II instrument, only one from Royal College of Physicians was found to have high-quality consensus guidelines for diagnosis and management of CRPS. Conclusion: Future CPGs should be backed by systematic literature searches, focus on guidelines clinical translation into clinical practice and applicability to the desired patient population.

Exploring the Differences Between Dominant and Nondominant Feet and Hands Bone Mineral Density

The assessment of regional bone mineral density (BMD) has proved to be useful for illustrating the impact of focal bone demineralization diseases on bone mass. In these scenario, a common practice is to compare the affected limb with the contralateral limb. However, there are no studies comparing BMD differences between dominant vs nondominant limbs at these sites. In addition, most studies have assessed BMD in specific ROIs (regions of interests) instead of in the whole limb. The purpose of our study was to compare the BMD of dominant vs nondominant hands and feet in healthy individuals, using both the whole limb software and specific ROIs. We performed a cross-sectional analysis on untrained women and men over 18 years of age who volunteered to participate. BMD (g/cm²), bone area (cm²) and BMC (bone mineral content) (g) were measured by Lunar Prodigy DXA (GE Healthcare, Madison, WI, USA), using 2 different approaches: whole limb/region software and specific ROIs. A total of 42 subjects (11 men and 31 women) were included. Mean age was 44.19 ± 10.49 years. BMD was greater in the dominant in comparison with the nondominant hand. The difference was 0.014 (95% CI, 0.009-0.018) for the whole hand BMD, 0.023 (95% CI, 0.003-0.044) for ROI 1, and 0.016 (95% CI, 0.003-0.029) for ROI 2. No significant differences were found between dominant and nondominant foot BMD, using the whole limb software and specific ROIs. To our knowledge, this is the first study to explore the differences in BMD, bone area and BMC in terms of limb dominance, supporting the usefulness of DXA as an accurate and objective complementary diagnostic or follow-up tool in focal bone demineralization diseases.

Peripheral mechanisms of chronic pain

Acutely, pain serves to protect us from potentially harmful stimuli, however damage to the somatosensory system can cause maladaptive changes in neurons leading to chronic pain. Although acute pain is fairly well controlled, chronic pain remains difficult to treat. Chronic pain is primarily a neuropathic condition, but studies examining the mechanisms underlying chronic pain are now looking beyond afferent nerve lesions and exploring new receptor targets, immune cells, and the role of the autonomic nervous system in contributing chronic pain conditions. The studies outlined in this review reveal how chronic pain is not only confined to alterations in the nervous system and presents findings on new treatment targets and for this debilitating disease.

Complex Regional Pain Syndrome: Practical Diagnostic and Treatment Guidelines, 5th Edition

There have been some modest recent advancements in the research of Complex Regional Pain Syndrome, yet the amount and quality of the work in this complicated multifactorial disease remains low (with some notable exceptions; e.g., the recent work on the dorsal root ganglion stimulation). The semi-systematic (though in some cases narrative) approach to review is necessary so that we might treat our patients while waiting for "better research." This semi-systematic review was conducted by experts in the field, (deliberately) some of whom are promising young researchers supplemented by the experience of "elder statesman" researchers, who all mention the system they have used to examine the literature. What we found is generally low- to medium-quality research with small numbers of subjects; however, there are some recent exceptions to this. The primary reason for this paucity of research is the fact that this is a rare disease, and it is very difficult to acquire a sufficient sample size for statistical significance using traditional statistical approaches. Several larger trials have failed, probably due to using the broad general diagnostic criteria (the "Budapest" criteria) in a multifactorial/multi-mechanism disease. Responsive subsets can often be identified in these larger trials, but not sufficient to achieve statistically significant results in the general diagnostic grouping. This being the case the authors have necessarily included data from less compelling protocols, including trials such as case series and even in some instances case reports/empirical information. In the humanitarian spirit of treating our often desperate patients with this rare syndrome, without great evidence, we must take what data we can find (as in this work) and tailor a treatment regime for each patient.

Visual Sensitivity in Complex Regional Pain Syndrome and Fibromyalgia: An Online Study

Perceptual anomalies can provide insights into underlying pathologies even when they are not the main symptom of many clinical conditions. Complex regional pain syndrome (CRPS) and fibromyalgia are chronic pain conditions associated with changes in the central nervous system, possibly leading to enhanced visual sensitivity. It is unclear whether this occurs more than for people with other types of pain. We examined visual sensitivity elicited by different stimuli and in daily life, through an online study of people with CRPS (n = 57), fibromyalgia (n = 74), other pain (n = 50), and no pain (n = 89). Respondents rated changes in pain, discomfort, or distress from viewing patterns with different spatial frequencies (lower-order visual processing), and reversible figures (bistable images; higher-order visual processing). We assessed visual sensitivity in daily life using the Leiden Visual Sensitivity Scale and Visual Discomfort Scale. Respondents with CRPS or fibromyalgia reported more visual discomfort than pain-related and pain-free controls while viewing striped patterns and a circle, with no effect of spatial frequency. They reported more pain while viewing a nonreversible square, but not reversible figures (Necker Cube, Duck/Rabbit). Finally, they reported more daily visual sensitivity than pain-related and pain-free controls. Suppressing visual cortical activity might benefit people with CRPS or fibromyalgia.

Risk factors related to complications of the fingers and hand after arthroscopic rotator cuff repair - carpal tunnel syndrome, flexor tenosynovitis, and complex regional pain syndrome

Hypothesis/Background

Complications involving the fingers and hand after arthroscopic rotator cuff repair (ARCR) include complex regional pain syndrome, carpal tunnel syndrome (CTS), and flexor tenosynovitis (TS). The aims of this study were to diagnose the complications after ARCR and investigate the risk factors that could predispose individuals to these finger and hand complications.

Methods

Fifty patients (50 shoulders) who underwent ARCR participated in this study. The patients’ ages ranged from 36 to 84 years (mean, 63 years). Before ARCR, we determined the disease history of the fingers and hand (CTS or TS) and subjectively assessed their symptoms using a questionnaire that included a scale ranging from 1 (no symptoms or no disability) to 5 (the worst symptoms or severest disability). ARCR was performed in all patients using suture anchors. The mean observation period after surgery was 15.5 months (range, 12-48 months). We diagnosed complications involving the fingers and hand after ARCR and investigated the preoperative, intraoperative, and postoperative risk factors that could predispose patients to these complications using univariable and multivariable analyses.

Results

After ARCR, 20 patients (20 hands) (40%) had complications of the fingers and hand. Among them, the diagnosis was CTS in 2 hands, TS in 15 hands, and both CTS and TS in 3 hands. None of the hands exhibited complex regional pain syndrome. These complications occurred at an average of 1.8 months (range, 0.1-4 months) after ARCR. In the 47 patients who did not have symptoms just before the operation, both univariable and multivariable analyses between the complication group (n = 17) and the no-complications group (n = 30) showed a significant difference in the presence of a past history of CTS or TS (complication frequency: past history: 88%, no past history: 25%) (P < .05) and the preoperative subjective assessment for edema of the fingers and hand (complication frequency: edema ≥ 2 points: 89%, edema < 2 points: 24%) (P < .05). There were no relationships between the other candidate intraoperative and postoperative factors and complications.

Conclusion

In all 20 hands with complications of the fingers and hand after ARCR, the diagnosis was CTS or TS. Complications of the fingers and hand after ARCR easily occurred in patients with a past history of CTS or TS and in patients with edema as per a subjective assessment. We speculate that the ARCR triggered the occurrence of CTS and TS postoperatively in patients who had subclinical CTS or TS before surgery.

Denying the Truth Does Not Change the Facts: A Systematic Analysis of Pseudoscientific Denial of Complex Regional Pain Syndrome

Purpose

Several articles have claimed that complex regional pain syndrome (CRPS) does not exist. Although a minority view, it is important to understand the arguments presented in these articles. We conducted a systematic literature search to evaluate the methodological quality of articles that claim CRPS does not exist. We then examined and refuted the arguments supporting this claim using up-to-date scientific literature on CRPS.

Methods

A systematic search was conducted in MEDLINE, EMBASE and Cochrane CENTRAL databases. Inclusion criteria for articles were (a) a claim made that CRPS does not exist or that CRPS is not a distinct diagnostic entity and (b) support of these claims with subsequent argument(s). The methodological quality of articles was assessed if possible.

Results

Nine articles were included for analysis: 4 narrative reviews, 2 personal views, 1 letter, 1 editorial and 1 case report. Seven points of controversy were used in these articles to argue that CRPS does not exist: 1) disagreement with the label “CRPS”; 2) the “unclear” pathophysiology; 3) the validity of the diagnostic criteria; 4) CRPS as a normal consequence of immobilization; 5) the role of psychological factors; 6) other identifiable causes for CRPS symptoms; and 7) the methodological quality of CRPS research.

Conclusion

The level of evidence for the claim that CRPS does not exist is very weak. Published accounts concluding that CRPS does not exist, in the absence of primary evidence to underpin them, can harm patients by encouraging dismissal of patients’ signs and symptoms.

The Importance of Cutaneous Innervation in Wound Healing: From Animal Studies to Clinical Applications

The skin is a neuroimmunoendocrine organ that regularly undergoes injury and repair. The complex process of wound healing relies heavily on the cutaneous nervous system. Despite the observation that wound healing deficiencies cause significant morbidity and mortality for patients with nervous dysfunction across many disciplinaries, the role of cutaneous innervation in wound repair has not been well elucidated. In a previous article, we learned the basics of cutaneous neuroanatomy and the important neuropeptides involved in the wound healing process. Currently, we aim to synthesize the basics with observations from animal models and human studies for a more comprehensive understanding of nervous system involvement in cutaneous wound healing. We have demonstrated in this review, the importance of the cutaneous nervous system in each phase of wound healing through basic science research, animal experiments, and human studies.

Vitamin C Could Prevent Complex Regional Pain Syndrome Type I in Trauma and Orthopedic Care? A Systematic Review of the Literature and Current Findings

The aim of this systematic review is to evaluate the efficacy of Vitamin C (VC) in preventing Complex Regional Pain Syndrome type I (CRPS-I) in fractures or surgery of the upper and lower extremities. During December 2020, Scopus and PubMed search was performed to analyze VC supplementation in preventing CRPS-I after trauma and orthopedic care, according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guideline. Patient, Intervention, Comparison, Outcomes, Study Design model, and a modified version of the Coleman Methodology Score were used to analyze the included studies. The research was limited from 1990 to December 2020. Initial screening results identified 649 studies. After reviewing each study, six clinical studies were included in the study. A total of 2026 patients of whom 632 male and 1394 female were collected in our systematic review. During the entire follow-up period, the occurrence of CRPS-I was evaluated in 1939 patients. Five of the six analyzed studies were favoring prophylactic use of the 500-1000 mg daily dose of VC for 45-50 days after orthopedic or trauma care for prevention of CRPS-I. Only one study found no benefit in VC supplementation compared with placebo to prevent CRPS-I. Analysis of the literature suggests that a daily 500-1000 mg VC supplementation may reduce the onset of CRPS-I in trauma of upper/lower extremities and in orthopedic surgery.

A Korean nationwide investigation of the national trend of complex regional pain syndrome vis-à-vis age-structural transformations

Background

The present study employed National Health Insurance Data to explore complex regional pain syndrome (CRPS) updated epidemiology in a Korean context.

Methods

A CRPS cohort for the period 2009-2016 was created based on Korean Standard Classification of Diseases codes alongside the national registry. The general CRPS incidence rate and the yearly incidence rate trend for every CRPS type were respectively the primary and secondary outcomes. Among the analyzed risk factors were age, sex, region, and hospital level for the yearly trend of the incidence rate for every CRPS. Statistical analysis was performed via the chi-square test and the linear and logistic linear regression tests.

Results

Over the research period, the number of registered patients was 122,210. The general CRPS incidence rate was 15.83 per 100,000, with 19.5 for type 1 and 12.1 for type 2. The condition exhibited a declining trend according to its overall occurrence, particularly in the case of type 2 (P < 0.001). On the other hand, registration was more pervasive among type 1 compared to type 2 patients (61.7% vs. 38.3%), while both types affected female individuals to a greater extent. Regarding age, individuals older than 60 years of age were associated with the highest prevalence in both types, regardless of sex (P < 0.001).

Conclusions

CRPS displayed an overall incidence of 15.83 per 100,000 in Korea and a declining trend for every age group which showed a negative association with the aging shift phenomenon.

Possible Therapeutic Options for Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) describes an array of painful conditions that are characterized by continuing regional pain. CRPS comprises severe and inappropriate pain in cases of complete recovery after trauma. Research on the pharmacological treatment of CRPS, however, has not been well investigated. In this study, we compared the pain relief effects of different drugs (URB597, pyrrolidine dithiocarbamate, and hydralazine) in a rat model of chronic post-ischemic pain-induced CRPS. After drug injection, CRPS-induced mechanical allodynia was significantly recovered. After three repetitive drug injections, mechanical sensitivity generally improved as hyper-nociception subsided. Reduced Nav1.7 expression at dorsal root ganglions (DRGs) was observed in the drug treatment groups. Neural imaging analysis revealed decreased neural activity for each drug treatment, compared to vehicle. In addition, treatments significantly reduced IL-1β, IL-6, and TNFα expression in DRGs. These results indicated that drugs could reduce the expression of inflammatory factors and alleviate the symptoms of chronic post-ischemic pain-induced CRPS.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Complex regional pain syndrome - Autoimmune or functional neurologic syndrome

Complex regional pain syndrome (CRPS) purports to explain extremity pain accompanied by a variety of subjective complaints, including sensitivity to touch, fatigue, burning sensations, allodynia and signs consistent with voluntary immobilization, including skin changes, edema and trophic changes. By its own definition, CRPS pain is disproportionate to any inciting event or underlying pathology, which means that the syndrome describes non-anatomic and exaggerated symptoms. Although CRPS was coined in the early 1990s, physicians have described unexplained exaggerated pain for centuries. Before a small group of researchers assigned this historical phenomenon with the name CRPS, other physicians in various subspecialties investigated the existence of a common pathophysiologic mechanism but found none. The literature was searched for evidence of a reproducible pathologic mechanism for CRPS. Although some have suggested that CRPS is an autoimmune disease, there is a paucity of evidence to support this. While cytokines such as IL-1β, IL-6 and TNF-α have been detected during the early phases of CRPS, this cannot lead to the conclusion that CRPS is an autoimmune disease, nor that it is an autoinflammatory disorder. Moreover, intravenous immunoglobulin has showed inconsistent results in the treatment of CRPS. On the other hand, CRPS has been found to meet at least three out of four criteria of malingering, which was previously a DSM-IV diagnosis; and its diagnostic criteria are virtually identical to current DSM-5 Functional Neurological Disorder ("FND"), and proposed ICD-11 classification, which includes FND as a distinct neurological diagnosis apart from any psychiatric condition. Unfortunately, the creation of CPRS is not merely misguided brand marketing. It has serious social and health issues. At least in part, the existence of CRPS has led to the labeling of many patients with a diagnosis that allows the inappropriate use of invasive surgery, addictive opioids, and ketamine. The CRPS hypothesis also ignores the nature and purpose of pain, as a symptom of some organic or psychological process. Physicians have long encountered patients who voice symptoms that cannot be biologically explained. Terminology historically used to describe this phenomenon have been medically unexplained symptoms ("MUS"), hysterical, somatic, non-organic, psychogenic, conversion disorder, or dissociative symptoms. The more recent trend describes disorders where there is a functional, rather than structural cause of the symptoms, as "functional disorders." Physicians report high success treating functional neurological symptoms with reassurance, physiotherapy, and cognitive behavior therapy measured in terms of functional improvement. The CRPS label, however, neither leads to functional improvement in these patients nor resolution of symptoms. Under principles of evidence-based medicine, the CRPS label should be abandoned and the syndrome should simply be considered a subset of FNDs, specifically Functional Pain Disorder; and treated appropriately.

Ignoring space around a painful limb? No evidence for a body-related visuospatial attention bias in complex regional pain syndrome

BACKGROUND

Complex Regional Pain Syndrome (CRPS) is a disorder of severe chronic pain in one or more limb(s). People with CRPS report unusual perceptions of the painful limb suggesting altered body representations, as well as difficulty attending to their affected limb (i.e., a 'neglect-like' attention bias). Altered body representations and attention in CRPS might be related, however, existing evidence is unclear. We hypothesized that if there were a body-related visuospatial attention bias in CRPS, then any attention bias away from the affected side should be larger for or limited to circumstances when the (impaired) body representation is involved in the task versus when this is not the case.

METHODS

We included 40 people with CRPS, 40 with other limb pain conditions, and 40 pain-free controls. In half of the people with pain, their upper limb was affected, in the other half their lower limb. We administered computerized tasks of spatial attention, including free viewing of images, shape cancellation, temporal order judgement, and dot-probe. The degree to which different versions of each task involved body representation was manipulated by one or more of the following: (1) presenting stimuli nearer versus further away from the body, (2) using body related versus neutral stimuli, and (3) inducing mental rotation of body parts versus no mental rotation. In addition to perceptual judgements, eye movements were recorded as a sensitive index of spatial attention. Bayesian repeated measures analyses were performed.

RESULTS

We found no evidence for a (body-related) visuospatial attention bias in upper limb CRPS. Secondary analyses suggested the presence of a body-related visuospatial attention bias away from the affected side in some participants with lower limb CRPS.

DISCUSSION

Our results add to growing evidence that there might be no general visuospatial attention bias away from the affected side in CRPS.

Usefulness of thermography in the diagnosis and classification of complex regional pain syndrome

INTRODUCTION

We propose a protocol for study of complex regional pain syndrome (CRPS) based on a battery of quantitative measures (skin thermography, electrochemical skin conductance and sensory thresholds) and apply such protocol to 5 representative cases of CRPS.

PATIENTS AND METHODS

5 CPRS cases (2 women/3 men) that met the Budapest criteria for the diagnosis of CRPS.

RESULTS

All patients showed spontaneous pain and allodynia. Two cases correspond to a stage I, in both the resting basal temperature was increased in the affected limb. Three cases reflect more advanced stages with a decrease in resting temperature and a delay in the recovery of the temperature when compared to contralateral limb.

DISCUSSION

These non-invasive quantitative functional tests not only improve the diagnostic accuracy of CRPS but also, they help us to stratify and understand the pathological processes of the disease.

Use of anticonvulsants and antidepressants for treatment of complex regional pain syndrome: a literature review

Complex regional pain syndrome (CRPS) is characterized by pain accompanied by symptoms including skin changes, sensory, motor, trophic changes and autonomic dysfunction. Anticonvulsants and antidepressants are commonly prescribed for neuropathic pain conditions; however, evidence is sparse whether these drugs are effective in reducing CRPS-related pain. As such, Pubmed was searched for studies published from January 1990 through March 2020; 13 studies were included in this review. Overall, evidence is considered insufficient for use of gabapentinoids for CRPS-related pain. However, three randomized controlled trials (RCTs) did find gabapentin to result in significant improvement in pain whereas one RCT reported use of amitriptyline to be equally as effective as gabapentin. Multiple case reports discussing the efficacy of pregabalin in pediatric CRPS patients, with relatively short duration of disease and underlying psychiatric illness, have been reported, but these findings need to be validated with RCTs.

Sex differences in neuro(auto)immunity and chronic sciatic nerve pain

Chronic pain occurs with greater frequency in women, with a parallel sexually dimorphic trend reported in sufferers of many autoimmune diseases. There is a need to continue examining neuro-immune-endocrine crosstalk in the context of sexual dimorphisms in chronic pain. Several phenomena in particular need to be further explored. In patients, autoantibodies to neural antigens have been associated with sensory pathway hyper-excitability, and the role of self-antigens released by damaged nerves remains to be defined. In addition, specific immune cells release pro-nociceptive cytokines that directly influence neural firing, while T lymphocytes activated by specific antigens secrete factors that either support nerve repair or exacerbate the damage. Modulating specific immune cell populations could therefore be a means to promote nerve recovery, with sex-specific outcomes. Understanding biological sex differences that maintain, or fail to maintain, neuroimmune homeostasis may inform the selection of sex-specific treatment regimens, improving chronic pain management by rebalancing neuroimmune feedback. Given the significance of interactions between nerves and immune cells in the generation and maintenance of neuropathic pain, this review focuses on sex differences and possible links with persistent autoimmune activity using sciatica as an example.

Lightning-Storm Periungual Capillaries in a Patient with Complex Regional Pain Syndrome Type I

Introduction

Complex regional pain syndrome (CRPS) is characterized by chronic pain out of proportion to injury following trauma. CRPS most commonly results after crush-type injury to the hand and may be associated with various cutaneous symptoms believed to be driven by vasomotor instability. Existing reports in the literature have employed a range of methodologies to describe and evaluate cutaneous and vascular changes in CRPS, though there exists no current gold standard for diagnosis.

Case Presentation

Here, we report a 71-year-old male with a 10-year history of CRPS who presented with abnormal capillaries on onychoscopy, demonstrating a "lightning-storm" pattern.

Conclusion

Previous studies have shown increased blood flow to the cutis in the early stage of CRPS, yet diminished cutaneous flow during the later stages. However, one study showed increased nail capillary diameter in patients with later stage CRPS. Due to a variety of reported clinical characteristics and a nonspecific clinic presentation, both the recognition and diagnosis of CRPS is difficult. Nail fold capillaroscopy may be a useful and accessible tool for evaluating patients with CRPS.

Is adhesive capsulitis of the shoulder a form of complex regional pain syndrome type I?

[No Abstract Available].

Evaluation of Analgesic and Anti-Inflammatory Activities of 80% Methanol Root Extract of Echinops kebericho M. (Asteraceae)

Background

Pain and inflammation are the major devastating health problems commonly treated with traditional medicinal plants in Ethiopia. Echinops kebericho M. (Asteraceae) is the one which is frequently used to treat pain and inflammation by traditional healers in Ethiopian folk medicine. However, the plant has not been scientifically evaluated for its traditionally claimed use. The present study aimed at the investigation of analgesic and anti-inflammatory activities of 80% methanol root extract of Echinops kebericho M. in mice model.

Methods

Successive maceration was used as a method of extraction using solvents of increasing polarity: methanol and water. After extraction of the roots with 80% hydro methanol, the crude extract was evaluated for its peripheral and central analgesic activities using acetic acid-induced writhing test and hot plate method, respectively, while its anti-inflammatory activity was evaluated using carrageenan- and formalin-induced paw edema. The extract was evaluated at 100, 200 and 400 mg/kg doses. The positive control groups were treated with ASA 150 mg/kg for writhing test, morphine 10 mg/kg for hot plat method, indomethacin 25 mg/kg and diclofenac 10 mg/kg for paw edema tests and vehicle, distilled water (10 mL/kg) treated mice were assigned as negative controls. All treatment administrations were performed orally.

Results

E. kebericho extract at all test doses showed statistically significant antinociceptive activity in both chemicals-induced peripheral and thermal-induced central pain in a dose dependent manner (p < 0.01 and p < 0.001). The greater analgesic activity was observed by the maximum dose of the extract (400 mg/kg) in both acetic acids-induced writhing test (57.84%) and hot plate method (69.40%). The effect of the extract was also statistically significant (p < 0.01 and p < 0.001) in both carrageenan and formalin-induced paw edema in dose dependent manner. Greater edema inhibition was observed by the highest dose (400 mg/kg) in both observations with the respective percentage values of 70.00% and 79.87%, respectively.

Conclusion

In general, the data obtained from the present study elucidated that the extract possessed a significant analgesic and anti-inflammatory activities and recommended for further studies.

Early detection and treatment of complications in the fingers and hand after arthroscopic rotator cuff repair

Background

Complications in the fingers and hand after arthroscopic rotator cuff repair (ARCR) have been reported to include carpal tunnel syndrome (CTS), flexor tenosynovitis (TS), and complex regional pain syndrome. These studies were conducted retrospectively; however, the reported complications have not been examined prospectively. The aim of this study was to evaluate the outcomes of early detection and treatment of the complications after ARCR.

Methods

Forty-six patients (48 shoulders) who underwent ARCR were prospectively examined to investigate complications in the fingers and hand after ARCR. We attempted to immediately detect and proactively treat these complications. We evaluated the outcomes of the early detection and treatment of the complications.

Results

Complications were observed in 17 hands (35%) and occurred an average of 1.5 months after ARCR. The symptoms in 3 hands resolved spontaneously, 2 hands were diagnosed with CTS, and 12 hands were diagnosed with TS. Of the 12 hands with TS, 11 exhibited no triggering of the fingers. Among the 14 hands diagnosed with CTS or TS, 13 hands (CTS: 2 hands, TS: 11 hands) were treated with corticosteroid injections; the mean interval between treatment initiation and symptom resolution was 1.0 months (0.5-3.0 months). None exhibited complex regional pain syndrome.

Conclusions

When symptoms occur in the fingers and hand after ARCR, CTS or TS should be primarily suspected. The diagnosis of TS must be made carefully because most patients with TS have no triggering. For patients with CTS or TS after ARCR, rapid corticosteroid injection administration can lead to improvement in these symptoms.

Highlighting the Role of Biomarkers of Inflammation in the Diagnosis and Management of Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is characterized by continuous pain that is often accompanied by sensory, motor, vasomotor, sudomotor, and trophic disturbances. If left untreated, it can have a significant impact on the quality of life of patients. The diagnosis of CRPS is currently based on a set of relatively subjective clinical criteria: the New International Association for the Study of Pain clinical diagnostic criteria for CRPS. There are still no objective laboratory tests to diagnose CRPS and there is a great need for simple, objective, and easily measurable biomarkers in the diagnosis and management of this disease. In this review, we discuss the role of inflammation in the multi-mechanism pathophysiology of CRPS and highlight the application of potential biomarkers of inflammation in the diagnosis and management of this disease.

Metabolomics in Central Sensitivity Syndromes

Central sensitization syndromes are a collection of frequently painful disorders that contribute to decreased quality of life and increased risk of opiate abuse. Although these disorders cause significant morbidity, they frequently lack reliable diagnostic tests. As such, technologies that can identify key moieties in central sensitization disorders may contribute to the identification of novel therapeutic targets and more precise treatment options. The analysis of small molecules in biological samples through metabolomics has improved greatly and may be the technology needed to identify key moieties in difficult to diagnose diseases. In this review, we discuss the current state of metabolomics as it relates to central sensitization disorders. From initial literature review until Feb 2020, PubMed, Embase, and Scopus were searched for applicable studies. We included cohort studies, case series, and interventional studies of both adults and children affected by central sensitivity syndromes. The majority of metabolomic studies addressing a CSS found significantly altered metabolites that allowed for differentiation of CSS patients from healthy controls. Therefore, the published literature overwhelmingly supports the use of metabolomics in CSS. Further research into these altered metabolites and their respective metabolic pathways may provide more reliable and effective therapeutics for these syndromes.

Median Neuropathy After Blood Draw Mimics Painful Clenched Fist Syndrome in a Child

Background: Clenched fist syndrome is a rare disorder, often attributed to a conversion disorder without anatomic basis. Here, we review the literature surrounding clenched fist syndrome and challenge the assumption it is always psychiatric in origin, via description of a case of clenched fist syndrome responsive to surgical nerve decompression. Methods: An unusual case of clenched fist syndrome is reviewed and discussed. Results: A child presenting with clenched fist syndrome failed conservative measures consisting of formal hand therapy, multidisciplinary pain management, and psychiatric treatment. On clinical examination, she had findings consistent with median nerve entrapment. After undergoing surgical decompression of the median nerve in the forearm and carpal tunnel, the clenched fist resolved immediately. Conclusions: Nerve compression may be an unrecognized factor underlying some cases of clenched fist syndrome. Evaluation by a hand surgeon or a hand therapist skilled in the detection of peripheral nerve entrapment or injury should be considered as part of the workup for this rare disorder.

Use of Oral Prednisolone and a 3-Phase Bone Scintigraphy in Patients with Complex Regional Pain Syndrome Type I

To compare the treatment effects of a high-dose and low-dose oral steroid regimen based on changes in the radioisotope uptake ratio (RUR) observed from three-phase bone scintigraphy (TPBS) in patients with complex regional pain syndrome type I (CRPS I), we retrospectively analyzed data of 34 patients with CRPS I from traumatic brain injury and stroke. Depending on the dose of steroid administered, patients were divided into high-dose (n = 14) and low-dose steroid groups (n = 20). We compared the severity scores, Kozin's classification scores, and RUR observed from TPBS between the two groups. There were significant changes in the severity scores and Kozin's classification between the baseline and 2 weeks from baseline (p < 0.05), however, there were no significant differences in terms of changes in the scores, classification, or the RUR observed from TPBS at 2 weeks from baseline (p > 0.05). There were no treatment-emergent adverse events (TEAEs) such as blood pressure elevation, impaired glycemic control, or gastrointestinal disturbances. Our results indicate that the efficacy profile of a low-dose oral steroid regimen is comparable to that of a high-dose regimen in alleviating symptoms in CRPS I patients. However, additional prospective, large-scale, multi-center studies are warranted to confirm our results.

What Is the Effect of Vitamin C on Finger Stiffness After Distal Radius Fracture? A Double-blind, Placebo-controlled Randomized Trial

BACKGROUND

It is proposed that vitamin C administration can reduce disproportionate pain and stiffness after distal radius fracture; however, randomized trials that tested this hypothesis have had inconsistent results.

QUESTIONS/PURPOSES

(1) Is administering vitamin C after distal radius fracture associated with better ROM, patient-reported upper extremity function, and pain scores? (2) What factors are associated with post-fracture finger stiffness and worse upper extremity function?

METHODS

This is a double-blind, randomized, placebo-controlled, noncrossover study. Between August 2014 and July 2017, we approached 204 consecutive patients, of which 195 were eligible, and 134 chose to participate. Participants were randomized to receive once-daily 500 mg vitamin C (67 participants) or placebo (67 participants) within 2 weeks after distal radius fracture. All patients received usual care at the discretion of their surgeon. The mean age of participants was 49 ± 17 years, 99 patients (74%) were women, and 83 (62%) were treated nonoperatively. The primary outcome was the distance between the fingertip and distal palmar crease 6 weeks after fracture. This measure is easy to obtain and previously has been shown to correlate with aggregate ROM of all finger joints. The secondary outcomes were total active finger motion, total active thumb motion, upper extremity-specific limitations, and pain intensity.An a priori power analysis suggested 126 patients would provide 80% power to detect a difference of 2 cm (SD 4.0) fingertip distance to palmar crease with α set at 0.05 using a two-tailed Student's t-test. Accounting for 5% lost to followup, we included 134 patients.All analyses were intention-to-treat. Ten participants of the intervention group and five of the placebo group were lost to followup. Their missing data were addressed by multiple imputation, after which we performed linear regression analysis for our outcome variables.

RESULTS

Administration of vitamin C was not associated with ROM, function, or pain scores at 6 weeks (distance to palmar crease: β -0.23; 95% CI -1.7 to 1.2; p = 0.754; finger ROM: β 4.9; 95% CI, -40 to 50; p = 0.829; thumb ROM: β 0.98; 95% CI, -18 to 20; p = 0.918, Patient-Reported Outcomes Measurement Information System [PROMIS] score: β 0.32; 95% CI, -2.6 to 3.2; p = 0.828; pain score: β -0.62; 95% CI, -0.62 to 0.89; p = 0.729) nor at 6 months (PROMIS score: β -0.21; 95% CI, -3.7 to 3.3; p = 0.904; pain score: β 0.31; 95% CI, -0.74 to 1.4; p = 0.559). At 6 weeks, we found that more finger stiffness was mildly associated with greater age (β -1.5; 95% CI, -2.8 to -0.083; p = 0.038). Thumb stiffness was mildly associated with greater age (β -0.72; 95% CI, -1.3 to -0.18; p = 0.009) and strongly associated with operative treatment (β -32; 95% CI, -50 to -13; p = 0.001). Greater pain interference was modestly associated with greater functional limitations at 6 weeks (β -0.32; 95% CI, -0.52 to -0.12; p = 0.002) and 6 months (β -0.36; 95% CI, -0.60 to -0.11; p = 0.004).

CONCLUSIONS

Vitamin C does not seem to facilitate recovery after distal radius fracture, but amelioration of maladaptation to nociception (pain interference) merits greater attention.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Complex regional pain syndrome in the young male population: a retrospective study of 200 Korean young male patients

Background

The aim of this study was to investigate the clinical characteristics of complex regional pain syndrome (CRPS) in young male patients in South Korea, especially focusing on the association with military service.

Methods

From January 2007 to May 2017, we investigated the electronic medical records of 430 consecutive patients, aged 18 to 30 years, who visited Seoul National University Hospital Pain Center, with a suspected diagnosis of CRPS at the initial visit. The following patient details were available for analysis: demographic and disease-related variables, relevance to military service, medications, and the treatment modalities received.

Results

Out of 430 patients, 245 (57.0%) were diagnosed with CRPS, of which, 200 were male patients and 45 were female patients. Of the male patients, 95 (47.5%) developed CRPS during military service. CRPS during military service was more likely to result from sprain/strain, and the incidence of CRPS was significantly higher in the lower extremities in patients from the military service group than in those from the non-military service group. During the follow-up period, 37.9% of male CRPS patients (n = 61/161) were treated successfully. Patients with moderate to severe initial pain intensity, and diagnosed during their military service, showed better outcomes.

Conclusions

Our results demonstrated that manifestation of CRPS in the young Korean population was more common in male and among those male CRPS patients, about half the cases developed during the military service period.

Bilaterally Reduced Intraepidermal Nerve Fiber Density in Unilateral CRPS-I

Objective

Findings regarding small nerve fiber damage in complex regional pain syndrome type I (CRPS-I) are not uniform, and studies have not included a matched healthy control group. The aim was to assess intraepidermal nerve fiber density (IENFD) in relation to thermal sensitivity of the same skin areas in CRPS-I patients and a gender- and age-matched healthy control group.

Methods

IENFD was investigated in skin biopsies from the CRPS-affected and contralateral limbs of eight CRPS-I patients and from an equivalent site in eight gender- and age-matched healthy controls (HCs). Thermal thresholds (cold/warm detection, cold- and heat-pain detection) were assessed on the affected limb, the matching contralateral limb, and on the equivalent limbs of HCs, and participants rated the intensity of cold/heat and pain to static thermal stimuli (5 °C and 40 °C).

Results

IENFD was significantly lower in both the affected and contralateral limbs of CRPS-I patients than HCs, but IENFD did not differ between the affected and contralateral limbs of patients. The heat pain threshold was lower in the affected CRPS-I limb than in HCs, but all other thermal thresholds were similar in both groups. CRPS-I patients rated the cold stimulus as colder and more painful in the affected limb, and the warm stimulus as hotter, bilaterally, than the HCs.

Conclusions

CRPS-I may be associated with bilateral small fiber damage, and perhaps small fiber neuropathy and bilateral disturbances in thermo-sensory perception. These disturbances could stem from a systemic response to injury or might increase the risk of developing CRPS-I after physical trauma.