Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-response study

Mechanisms of complex regional pain syndrome

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

Over-expression of miR-3584-5p Represses Nav1.8 Channel Aggravating Neuropathic Pain caused by Chronic Constriction Injury

Nav1.8, a tetrodotoxin-resistant voltage-gated sodium channels (VGSCs) subtype encoded by SCN10A, which plays an important role in the production and transmission of peripheral neuropathic pain signals. Studies have shown that VGSCs may be key targets of MicroRNAs (miRNAs) in the regulation of neuropathic pain. In our study, bioinformatics analysis showed that the targeting relationship between miR-3584-5p and Nav1.8 was the most closely. The purpose of this study was to investigate the roles of miR-3584-5p and Nav1.8 in neuropathic pain. The effects of miR-3584-5p on chronic constriction injury (CCI)-induced neuropathic pain in rats was investigated by intrathecal injection of miR-3584-5p agomir (an agonist, 20 μM, 15 μL) or antagomir (an antagonist, 20 μM, 15 μL). The results showed that over-expression of miR-3584-5p aggravated neuronal injury by hematoxylin-eosin (H&E) staining and mechanical/thermal hypersensitivity in CCI rats. MiR-3584-5p indirectly inhibited the expression of Nav1.8 by up-regulating the expression of key proteins in the ERK5/CREB signaling pathway, and also inhibited the current density of the Nav1.8 channel, changed its channel dynamics characteristic, thereby accelerating the transmission of pain signals, and further aggravating pain. Similarly, in PC12 and SH-SY5Y cell cultures, miR-3584-5p increased the level of reactive oxygen species (ROS) and inhibited mitochondrial membrane potential (Δψm) in the mitochondrial pathway, decreased the ratio of apoptosis-related factor Bcl-2/Bax, and thus promoted neuronal apoptosis. In brief, over-expression of miR-3584-5p aggravates neuropathic pain by directly inhibiting the current density of Nav1.8 channel and altering its channel dynamics, or indirectly inhibiting Nav1.8 expression through ERK5/CREB pathway, and promoting apoptosis through mitochondrial pathway.

From a Symptom-Based to a Mechanism-Based Pharmacotherapeutic Treatment in Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a debilitating painful condition of a distal extremity that can develop after tissue damage. CRPS is thought to be a multimechanism syndrome and ideally the most prominent mechanism(s) should be targeted by drugs in an individually tailored manner. This review gives an overview of the action and evidence of current and future pharmacotherapeutic options for CRPS. The available options are grouped in four categories by their therapeutic actions on the CRPS mechanisms, i.e. inflammation, central sensitisation, vasomotor disturbances and motor disturbances. More knowledge about the underlying mechanisms of CRPS helps to specifically target important CRPS mechanisms. In the future, objective biomarkers could potentially aid in selecting appropriate mechanism-based drugs in order to increase the effectiveness of CRPS treatment. Using this approach, current and future pharmacotherapeutic options for CRPS should be studied in multicentre trials to prove their efficacy. The ultimate goal is to shift the symptom-based selection of therapy into a mechanism-based selection of therapy in CRPS.

Non-drug pain relievers active on non-opioid pain mechanisms

This review is aimed to summarize the pain-relieving effect of non-drug substances, mostly prescribed as integrators in treatment of pain, including especially in chronic postoperative pain (CPSP) and in chronic back pain after acute episodes. Their use reflects the fact that the current treatments for these syndromes continue to pose problems of unsatisfactory responses in a significant portion of patients and/or of an excess of side effects like those noted in the present opioid crisis. As integrators are frequently introduced into the market without adequate clinical testing, this review is aimed to collect the present scientific evidence either preclinical or clinical for their effectiveness. In particular, we reviewed the data on the use of: B vitamins; vitamin C; vitamin D; alpha lipoic acid (ALA); N-acetylcysteine; acetyl L-carnitine; curcumin; boswellia serrata; magnesium; coenzyme Q10, and palmitoylethanolamide. The combination of preclinical findings and clinical observations strongly indicate that these compounds deserve more careful attention, some of them having interesting clinical potentials also in preventing chronic pain after an acute episode. In particular, examining their putative mechanisms of action it emerges that combinations of few of them may exert an extraordinary spectrum of activities on a large variety of pain-associated pathways and may be eventually used in combination with more traditional pain killers in order to extend the duration of the effect and to lower the doses. Convincing examples of effective combinations against pain are vitamin B complex plus gabapentin for CPSP, including neuropathic pain; vitamin B complex plus diclofenac against low back pain and also in association with gabapentin, and ALA for burning mouth syndrome. These as well as other examples need, however, careful controlled independent clinical studies confirming their role in therapy.

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.

The Role of Vitamin C in Reducing Pain Associated With Diabetic Neuropathy

Introduction: Neuropathic pain is a painful condition that arises after a lesion or an insult to the somatosensory nervous system, either in a central or peripheral location. The most common cause of neuropathic pain is diabetes. Controlled trials have been conducted on recent advancements in medicine to investigate the effect of vitamin C in the treatment of neuropathic pain. In this study, we aim to investigate the role of vitamin C in reducing pain associated with diabetic neuropathy.

Methods: This open-label, parallel-arm, interventional study was conducted in a public tertiary care hospital in Pakistan from April 2019 to March 2021. A total of 300 type II diabetic patients with newly diagnosed painful peripheral diabetic neuropathy, of either gender, were enrolled in the study. The intervention group received 60 mg duloxetine along with 200 mg oral vitamin C. The control group received 60 mg duloxetine without any additional intervention. Patients were asked to return for follow-up after 12 weeks.

Results: The mean visual analog score (VAS) was significantly lower in both, the intervention (5.54 ± 0.81 vs. 6.72 ± 0.90; p-value: <0.0001) and the control group (5.91 ± 0.80 vs. 6.79 ± 0.94; p-value: <0.0001), at week 12 compared to day 0. However, in comparison, VAS score in intervention at week 12 was significantly lower as compared to the control group (5.54 ± 0.81 vs. 5.91 ± 0.80; p-value: 0.0002).

Conclusion: The use of vitamin C could be cost-effective and would be a safe and useful adjunctive therapy for pain associated with diabetic peripheral neuropathy.

A meta-analysis of randomized clinical trials on the impact of oral vitamin C supplementation on first-year outcomes in orthopedic patients

This meta-analysis aimed at investigating the impact of oral vitamin C supplementation on the post-procedural recovery of orthopedic patients, including functional outcomes and complex regional pain syndrome type I (CRPS I). Literature search using the Medline, Cochrane Library, and Embase databases from inception till March 2021 identified seven eligible randomized controlled trials with 1,361 participants. Forest plot revealed no significant difference in the functional outcomes at 6-12 months [standardized mean difference (SMD) = -0.00, 95% CI - 0.19 to 0.18, 467 patients], risk of overall complications (RR = 0.98, 95% CI 0.68 to 1.39, 426 patients), and pain severity at 3-6 months (SMD = - 0.18, 95% CI - 0.49 to 0.12, 486 patients) between patients with and without oral vitamin C supplementation. Pooled analysis showed that vitamin C treatment reduced the risk of CRPS I regardless of dosage (RR = 0.46, 95% CI 0.25 to 0.85, 1143 patients). In conclusion, the current meta-analysis demonstrated that oral vitamin C supplementation may reduce the risk of complex regional pain syndrome type I but did not improve the functional outcomes in orthopedic patients. Nevertheless, because of the small number of trials included in the present study, further large-scale clinical studies are warranted to support our findings.

Ascorbic Acid in the Acute Care Setting

Ascorbic acid (AA) is an essential nutrient with many physiologic roles not limited to the prevention of scurvy. Beyond its role as a supplement, it has gained popularity in the acute care setting as an inexpensive medication for a variety of conditions. Because of limitations with absorption of oral formulations and reduced serum concentrations observed in acute illness, intravenous (IV) administration, and higher doses, may be needed to produce the desired serum concentrations for a particular indication. Following a PubMed search, we reviewed published studies relevant to AA in the acute care setting and summarized the results in a narrative review. In the acute care setting, AA may be used for improved wound healing, improved organ function in sepsis and acute respiratory distress syndrome, faster resolution of vasoplegic shock after cardiac surgery, reduction of resuscitative fluids in severe burn injury, and as an adjunctive analgesic, among other uses. Each indication differs in its level of evidence supporting exogenous administration of AA, but overall, AA was not commonly associated with adverse effects in the identified studies. Use of AA remains an active area of clinical investigation for various indications in the acute care patient population.

Intravenous Administration of Vitamin C in the Treatment of Herpes Zoster-Associated Pain: Two Case Reports and Literature Review

Background

Herpes zoster (HZ) is an acute inflammatory neurocutaneous disease caused by the reactivation of varicella-zoster virus. It is estimated that the incidence of postherpetic neuralgia following HZ is 10–20%. The leading risk factors of the prognosis are aging and immunity dysfunction. Vitamin C plays a pivoted role in enhancing white blood cell function. Epidemiological evidence and clinical studies have indicated an association between pain and suboptimal vitamin C status. At present, vitamin C has been used as an additional option in the treatment of HZ-associated pain. Despite the current controversy, case reports and randomized controlled studies have indicated that both acute- and postherpetic neuralgia can be dramatically alleviated following intravenous vitamin C infusions. Case Presentation. Two patients (male aged 72 and female 78 years) with HZ did not respond well to antiviral therapy and analgesics. Skin lesions in the right groin and front thigh healed after early antiviral therapy, but the outbreak of pain persisted in the male patient. The female patient presented to our clinic with clusters of rashes in the right forehead with severe edema of her right upper eyelid. Because nerve blockade could not be conducted for both patients, intravenous infusion of vitamin C was applied and resulted in an immediate remission of the breakthrough pain in the male patient and cutaneous lesions in the female patient.

Conclusions

The use of vitamin C appears to be an emerging treatment alternative for attenuating HZ and PHN pain. Hence, we recommend the addition of concomitant use of intravenously administered vitamin C into therapeutic strategies in the treatment of HZ-associated pain, especially for therapy-resistant cases. Furthermore, animal studies are required to determine analgesic mechanisms of vitamin C, and more randomized clinical trials are essential to further determine the optimal dose and timing of administration of vitamin C.

Complex regional pain syndrome: an evolving perspective

BACKGROUND

Complex regional pain syndrome (CRPS) is a heterogenous and poorly understood condition that can be provoked by quite minor injuries. The symptoms and signs of CRPS persist, long after the patient has recovered from the inciting event. In some cases, there is a clear association with a peripheral nerve injury. The degree of disability produced by CRPS is often out of proportion to the scale of the original insult and the condition is associated with protracted recovery times and frequent litigation.

METHODS

We have performed a PubMed literature search, referenced landmark papers in the field and included a national expert in peripheral nerve injury and repair in our team of authors.

RESULTS AND CONCLUSIONS

The diagnostic criteria for CRPS have changed repeatedly over the last two centuries and much of the historical literature is difficult to compare with more recent research. In this review article, we consider how our understanding of the condition has evolved and discuss its pathogenesis, its apparent heterogenicity and the various investigations and treatments available to the clinician.

Regional vitamin C in Bier block reduces the incidence of CRPS-1 following distal radius fracture surgery

BACKGROUND

Systemic vitamin C supplementation after wrist fracture has been suggested to reduce the incidence of complex regional pain syndrome (CRPS). This study aimed to evaluate the effect of regional vitamin C in Bier block in the early phase of fracture on CRPS occurrence following surgery for distal radius fractures.

METHODS

Seventy-four patients with isolated extra-articular distal radius fracture with the plan of fixation under Bier block were enrolled. Patients were assigned randomly into two groups: receiving either 500 mg vitamin C or sterile water as a Bier block adjuvant. Both groups received 500 mg of oral vitamin C for six weeks. The patients were evaluated for CRPS signs and symptoms at 2, 4, 6, and 12 weeks post-surgery.

RESULTS

The overall incidence of CRPS 12 weeks after surgery in the vitamin C group was significantly less than the controls (22.9% vs 45.5%, p = 0.04). Logistic regression analysis showed that the only significant contribution in predicting the incidence of CRPS came from the intervention variable (OR 0.26, CI95% 0.08-0.85; P = 0.027).

CONCLUSIONS

The findings suggest that adding vitamin C 500 mg to the local anesthetic in Bier block significantly reduces the incidence of CRPS following distal radius fractures.

Low vitamin D levels in post-menopausal women are associated with complex regional pain syndrome type I in surgically treated distal radius fractures

BACKGROUND

Complex regional pain syndrome type I (CRPS I) is a chronic devastating condition and a relatively common complication of distal radius fractures (DRF). The purpose of this study was to investigate the relationship of vitamin D levels in surgically treated post-menopausal women with CRPS I occurrence in DRF.

METHODS

From February 2016 to March 2017, 158 surgically treated post-menopausal patients with DRF were enrolled. Exclusion criteria were (1) patients who had been taking vitamin D or osteoporosis medication at the time of injury; (2) patients with medical factors that may affect vitamin D levels; (3) patients who were reluctant to enroll in the study; and (4) patient with additional fractures, ligamentous injuries, or neuropathy. A total of 107 patients were available for final analysis. We compared the serum vitamin D levels in post-menopausal women with DRF with CRPS I (group 1) and without CRPS I (group 2). Bone mineral density (BMD) of the femur and spine, osteocalcin, alkaline phosphatase (ALP), body mass index (BMI) were also measured.

RESULTS

The average age at the time of surgery was 66.5 years (range, 39-86 years). The mean follow-up period was 16.3 months after surgery. Among the 107 surgically treated DRF patients, 19 (18%) met the Budapest criteria for CRPS I during the follow-up period. The mean serum vitamin D level in group 1 (15.2 ng/ml) was significantly lower than that in group 2 (20.5 ng/ml, p = 0.027). The mean values of osteocalcin, ALP, BMI, and BMD were not significantly different between the groups.

CONCLUSION

Lower vitamin D levels in post-menopausal women can increase CRPS I occurrence in distal radius fractures.

A randomized controlled trial on Aspirin and complex regional pain syndrome after radius fractures

Complex regional pain syndrome (CRPS) is often diagnosed in patients who are recovered with surgery or injury. CRPS is usually diagnosed in patients recovering from distal radius fractures. The aim of study was the effects of aspirin in prevention of the complex regional pain syndrome (CRPS) following a fracture of distal radius. In a double-blind, randomized controlled trial, 91 patients with unilateral extra-articular distal radius fractures were randomly allocated to receive either placebo (PLA) or 500 mg of aspirin (ASA) daily for 7 days. The effect of aspirin on the occurrence of CRPS was evaluated. The patients were assessed clinically and radiographically in the second, fourth and twelfth weeks by a physician who was unaware of the treatment allocation. Ninety-one patients (ASA, n=44; PLA, n=47) were enrolled in the study. The prevalence of CRPS in all patients was 16.5%. The prevalence of CRPS in the aspirin group was lower (13.6%) than the placebo group (19.1%), but this difference was not statistically significant. The only significant difference was the lower rate of regional osteoporosis seen in the radiographs of aspirin group. Mean age was significantly higher in the patients with CRPS. Also, comminuted distal radius fractures (A3-type) were significantly more common in the patients with CRPS. Administration of aspirin in patients with a distal radius fracture was associated with a lower incidence of CRPS, but, not statistically significant. Further investigations needs to be done with a larger sample size, longer follow-up period and multi-center design.

A medical mystery of complex regional pain syndrome

Complex regional pain syndrome (CRPS) is a condition of neuropathic pain, which is characterized by significant autonomic and inflammatory features. CRPS occurs in patients who have limb surgery, limb fractures, or trauma. Many patients may have pain resolve within twelve months of the inciting incident; however, a small subset progresses to the chronic form. This transitional process often happens by changing from warm CRPS with dominant inflammatory phase to cold CRPS, in which autonomic characteristics or manifestations dominate. Several peripheral and central mechanisms are involved, which might vary among individuals over a period of time. Other contributors include peripheral and central sensitization, autonomic alterations, inflammatory and immune changes, neurochemical changes, and psychological and genetic factors. Although effective management of the chronic CRPS form is often challenging, there are a few high quality randomized controlled trials that support the efficacy of the most commonly used therapeutic approaches.

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.

Influence of vitamin C on the incidence of CRPS-I after subacromial shoulder surgery

PURPOSE

The primary aim of this study was to determine whether postoperative administration of vitamin C (VC) is associated with reduced risk of complex regional pain syndrome type I (CRPS-I) after subacromial shoulder surgery (SaSS). The secondary objective of the study was to identify risk factor for the development of CRPS-I after SaSS.

MATERIALS AND METHODS

A retrospective cohort study was performed to evaluate 542 patients undergoing SaSS from January 2015 to December 2016. The cohort was divided into two groups based on VC administration [Group I (no VC) and Group II (500 mg/day oral VC for 50 days postoperatively)]. The relationship between VC administration and development of CRPS-I was assessed. Demographics, preoperative clinical parameters, and operative variables were evaluated to determine their effect on the incidence of CRPS-I.

RESULTS

A total of 267 patients (Group II) undergoing SaSS received VC, and 266 patients (Group I) did not. The incidence of CRPS-I was significantly different between two groups (36(13%) vs 18(7%), p = 0.009). Multivariable regression, however, demonstrated that VC reduced the risk of CRPS-I after SaSS by > 50% (aOR = 0.49; 95% CI 0.27-0.91). Patients undergoing open surgery (aOR = 2.19; 95% CI 1.2-4.0) were more likely to develop CRPS-I postoperatively. Higher preoperative Constant score (aOR = 0.94; 95% CI 0.91-0.98) was associated with lower risk for CRPS-I development.

CONCLUSIONS

The present study found that VC administered prophylactically for 50 days postoperatively is effective in preventing CRPS-I development after SaSS. CRPS-I is a common complication following SaSS, especially in the setting of an open approach. The authors recommend preventive management with VC and arthroscopic approaches when possible for SaSS.

LEVEL OF EVIDENCE III

Retrospective comparative study.

Reflex Sympathetic Dystrophy of the Right Hand following an Acute Traumatic Injury

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy, is a chronic neuropathic pain disorder with significant autonomic features. Recently, it has been recognized that CRPS is not simply a sympathetically mediated peripheral pain condition but rather a disease of the central nervous system as well. Herein, we present a case of a patient who presented with complaints of severe pain following a traumatic event, severing his extensor tendon of his right fifth finger. 

Manual Therapy Reduces Pain Behavior and Oxidative Stress in a Murine Model of Complex Regional Pain Syndrome Type I

Complex regional pain syndrome type I (CRPS-I) is a chronic painful condition. We investigated whether manual therapy (MT), in a chronic post-ischemia pain (CPIP) model, is capable of reducing pain behavior and oxidative stress. Male Swiss mice were subjected to ischemia-reperfusion (IR) to mimic CRPS-I. Animals received ankle joint mobilization 48h after the IR procedure, and response to mechanical stimuli was evaluated. For biochemical analyses, mitochondrial function as well as oxidative stress thiobarbituric acid reactive substances (TBARS), protein carbonyls, antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) levels were determined. IR induced mechanical hyperalgesia which was subsequently reduced by acute MT treatment. The concentrations of oxidative stress parameters were increased following IR with MT treatment preventing these increases in malondialdehyde (MDA) and carbonyls protein. IR diminished the levels of SOD and CAT activity and MT treatment prevented this decrease in CAT but not in SOD activity. IR also diminished mitochondrial complex activity, and MT treatment was ineffective in preventing this decrease. In conclusion, repeated sessions of MT resulted in antihyperalgesic effects mediated, at least partially, through the prevention of an increase of MDA and protein carbonyls levels and an improvement in the antioxidant defense system.

Complications in the Management of Distal Radius Fractures: How Do We Avoid them?

PURPOSE OF THIS REVIEW

Distal radius fractures are one of the most common fractures in the upper extremity. The purpose of this review is to outline common complications that may arise when caring for distal radius fractures and to describe the treatment strategies when faced with such complications.

RECENT FINDINGS

Tendon complications are not uncommon after distal radius fractures. Recent literature highlights new plating technology for dorsal plating techniques. Moreover, new literature has outlined parameters for flexor tendon complications when using volar locking plates in an effort to avoid flexor tendon irritation and rupture. In summary, it is important to understand the various complications that can arise when treating distal radius fractures in an effort to avoid suboptimal outcomes.

Complex regional pain syndrome: a narrative review for the practising clinician

Complex regional pain syndrome (CRPS) is a life-altering condition that usually affects the extremities after a trauma or nerve injury. The physiologic changes that occur as a result of the inciting injury are complex, as the name of the syndrome implies. The pain and disability associated with CRPS often lead to psychological co-morbidities that create a vicious cycle of pain, isolation, and depression. We review recent developments in the understanding of CRPS and advancements in management of this syndrome. Further research in targeting specific mechanisms involved in the pathophysiology of CRPS should lead to prevention of this condition.

Early complications and radiological outcome after distal radius fractures stabilized by volar angular stable locking plate

INTRODUCTION

Distal radius fractures (DRF) are the most common fractures of the upper extremities. The incidence is expected to continue rising in the next years due to the increased life expectancy. Palmar locking plate stabilizing has since become the standard treatment for dorsally displaced DRF with a complication rate of 8-39% reported in the literature. Main aim of this study was to investigate the incidence of complications after DRF stabilization using palmar angular stable locking plate.

METHODS

A retrospective medical records review conducted from January 2013 to December 2016 included a total of 392 patients with DRF, that were stabilized using palmar angular stable locking plate and showed a minimum follow-up of 3 months. The group comprised 259 female and 133 male patients with a mean follow-up interval of 11 months (range 3-52 months). All recorded complications were documented. Range of motion (ROM) in extension, flexion, supination, pronation, radial- and ulnar deviation of the last follow-up was noted. Age was divided into younger than 65 years (< 65 years) and older than 65 years (≥ 65 years). The primary, immediate postoperative and final checkup radiographs were scrutinized for alignment and intra-articular step-off.

RESULTS

A total of 51 (13%) early and 17 late (4%) complications were recorded in 392 patients. The most common complications included carpal tunnel syndrome (3%), complex regional pain syndrome (3%) and loss of reduction (2%). Of the 68 complications, only 25 (6%) were directly related to the plate. 73% of all complications occurred in AO type C fractures. Patients without complications showed a significantly better ROM in extension, flexion, pronation and supination than patients with complications. No significant differences in incidence of complications, ROM or loss of reduction could be found between patients over and under 65 years of age. Gender and type of immobilization showed no significant influence on the complication rate.

CONCLUSIONS

Stabilization of DRF by palmar angular stable locking plate is a safe form of treatment. In the majority of the cases a good clinical and radiological outcome with no complications was documented. Gender and type of immobilization had no impact on the complication rate and an age over 65 years is not associated with an increased risk for complications or restricted ROM.

Vitamin C in the critically ill - indications and controversies

Ascorbic acid (vitamin C) elicits pleiotropic effects in the body. Among its functions, it serves as a potent anti-oxidant, a co-factor in collagen and catecholamine synthesis, and a modulator of immune cell biology. Furthermore, an increasing body of evidence suggests that high-dose vitamin C administration improves hemodynamics, end-organ function, and may improve survival in critically ill patients. This article reviews studies that evaluate vitamin C in pre-clinical models and clinical trials with respect to its therapeutic potential.

Oxidative Stress Contributes to Fracture/Cast-Induced Inflammation and Pain in a Rat Model of Complex Regional Pain Syndrome

Clinical evidence suggests that vitamin C (Vit C) may protect against the development of complex regional pain syndrome (CRPS) after fracture or surgery. Tibia fracture followed by 4 weeks of cast immobilization (fracture/cast) in rats results in nociceptive, vascular, and bone changes resembling clinical CRPS. In this study, fracture/cast rats were treated with the oxidative stress inhibitors Vit C, N-acetyl cysteine, or 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl to examine their effects on CRPS-related nociceptive and vascular changes. Administration of these agents significantly reduced fracture/cast-induced cutaneous allodynia by 64 to 78%, muscle hyperalgesia by 34 to 40%, and hind limb unweighting by 48 to 89%. Treatments with Vit C and N-acetyl cysteine reduced the oxidative stress markers malondialdehyde in the skin, muscle, and sciatic nerve, and lactate in the gastrocnemius muscle of the fracture/cast limb. Furthermore, Vit C treatment inhibited the post-fracture upregulation of substance P and calcitonin gene-related peptide in the sciatic nerve and the increased expression of the pain-related inflammatory mediators, including interleukin (IL)-6, and nerve growth factor in the skin and IL-1β, and IL-6 in the muscle of the post-fracture/cast limb. These data suggest that oxidative stress may contribute to the nociceptive features of the rat CRPS model.

PERSPECTIVE

Vit C reduced the CRPS-like signs, oxidative stress, and the upregulation of neuropeptide production and inflammatory mediators observed after tibia fracture and casting in rats. Limiting oxidative stress by use of Vit C or alternative strategies could reduce the risk of developing CRPS after surgery or other forms of trauma.

Complex Regional Pain Syndrome, Current Concepts and Treatment Options

PURPOSE OF REVIEW

Complex regional pain syndrome (CRPS) refers to a chronic pain condition that is characterized by progressively worsening spontaneous regional pain without dermatomal distribution. The symptomatology includes pain out of proportion in time and severity to the inciting event. The purpose of this review is to present the most current information concerning epidemiology, diagnosis, pathophysiology, and therapy for CRPS.

RECENT FINDINGS

In recent years, discovery of pathophysiologic mechanisms of CRPS has led to significant strides in the understanding of the disease process. Continued elucidation of the underlying pathophysiological mechanisms will allow for the development of more targeted and effective evidence-based therapy protocols. Further large clinical trials are needed to investigate mechanisms and treatment of the disorder.

Microvascular Response in Patients with Complex Regional Pain Syndrome as Measured by Laser Doppler Imaging

Objectives

Our aim was to investigate the hypothesis that microvascular dysfunction occurs in patients with CRPS. Specifically, whether there were functional differences in either deeper cutaneous blood vessels or more superficial nutritive vessels between the affected and unaffected limb in patients with CRPS, and between CRPS patients and healthy control subjects.

Methods

Twenty‐two patients with CRPS (five male; mean age 45 years; eight upper limb involvement, 14 lower limb) and 23 healthy control subjects (one male; 43 years) were recruited. Microvascular flow at affected and unaffected contralateral sites was measured, following local heating, using laser Doppler imaging (red/green wavelengths). Corresponding sites were imaged in healthy controls. Maximum flux level and area under the curve (first 20 scans, AUC20) were measured.

Results

Vasodilator responses to heat were similar in affected and unaffected limbs, and in healthy controls. For example, median (IQR) “red” AUC20 in CRPS was 138.6 (120.0–152.9)% change from baseline in affected limb and 135.0 (120.7–166.8)% in unaffected limb, and (in healthy controls) 133.1 (117.2–145.9)% and 139.1% (126.0–162.1) in limb 1 and 2.

Conclusions

We found no impairment of vasodilation in cutaneous microvessels in CRPS. The vasomotor changes in CRPS may relate to larger vessel dysfunction.

An Insight and Update on the Analgesic Properties of Vitamin C

Pain is an unpleasant subjective feeling having implications on both physical and mental realm. Multiple dimensions of pain involving behavioral, spiritual, emotional, and cognitive changes have been studied and pathways elucidated. It is stressed that the nature in which pain is modulated and perceived at a higher center is a complex phenomenon. One of the main goals of pain modulation is to modify pain to a more tolerable level, rather than its complete eradication. Different pain management interventions were tried but have effects that are more adverse. Till date, the only reliable pain blockers are analgesics and anti-inflammatory drugs in the form of opioids and non-opioids. Despite this, most of the drugs are ineffective at various levels, furthermore, adding to complications. Thus, there is an urgent need for effective intervention with minimal side effects. Ascorbic acid, popularly known as vitamin C, has shown to exhibit promising analgesic properties. The literature is sparse with the usage of the drug in various forms of pain. This review focuses on the dynamics and kinetics of vitamin C and its usage in various forms of pain. With minimal adverse effects, the drug is shown to perform well in different types of pain disorders, thus paving way for alternative interventional agent for pain management.

The Efficacy of Vitamin C on Postoperative Outcomes after Posterior Lumbar Interbody Fusion: A Randomized, Placebo-Controlled Trial

Background

Vitamin C has critical features relavant to postoperative pain management and functional improvement; however, no study has yet evaluated the effectiveness of vitamin C on improving the surgical outcomes for spine pathologies. Thus, this study aimed to explore the impact of vitamin C on postoperative outcomes after single-level posterior lumbar interbody fusion (PLIF) for lumbar spinal stenosis in prospectively randomized design. We conducted a 1-year prospective, randomized, placebo-controlled, double-blind study to evaluate the impact of vitamin C on the postoperative outcomes after PLIF surgery.

Methods

A total of 123 eligible patients were randomly assigned to either group A (62 patients with vitamin C) or group B (61 patients with placebo). Patient follow-up was continued for at least 1 year after surgery. The primary outcome measure was pain intensity in the lower back using a visual analogue scale. The secondary outcome measures were: (1) the clinical outcome assessed using the Oswestry Disability Index (ODI); (2) the fusion rate assessed using dynamic radiographs and computed tomography scans; and (3) complications.

Results

Pain intensity in the lower back was significantly improved in both groups compared with preoperative pain intensity, but no significant difference was observed between the 2 groups over the follow-up period. The ODI score of group A at the third postoperative month was significantly higher than the score of group B. After the sixth postoperative month, the ODI score of group A was slightly higher than the score of group B; however, this difference was not significant. The fusion rates at 1 year after surgery and the complication rates were not significantly different between the 2 groups.

Conclusions

Postoperative pain intensity, the primary outcome measure, was not significantly different at 1 year after surgery between the 2 groups. However, vitamin C may be associated with improving functional status after PLIF surgery, especially during the first 3 postoperative months.

The role of vitamin C in the treatment of pain: new insights

The vitamin C deficiency disease scurvy is characterised by musculoskeletal pain and recent epidemiological evidence has indicated an association between suboptimal vitamin C status and spinal pain. Furthermore, accumulating evidence indicates that vitamin C administration can exhibit analgesic properties in some clinical conditions. The prevalence of hypovitaminosis C and vitamin C deficiency is high in various patient groups, such as surgical/trauma, infectious diseases and cancer patients. A number of recent clinical studies have shown that vitamin C administration to patients with chronic regional pain syndrome decreases their symptoms. Acute herpetic and post-herpetic neuralgia is also diminished with high dose vitamin C administration. Furthermore, cancer-related pain is decreased with high dose vitamin C, contributing to enhanced patient quality of life. A number of mechanisms have been proposed for vitamin C’s analgesic properties. Herein we propose a novel analgesic mechanism for vitamin C; as a cofactor for the biosynthesis of amidated opioid peptides. It is well established that vitamin C participates in the amidation of peptides, through acting as a cofactor for peptidyl-glycine α-amidating monooxygenase, the only enzyme known to amidate the carboxy terminal residue of neuropeptides and peptide hormones. Support for our proposed mechanism comes from studies which show a decreased requirement for opioid analgesics in surgical and cancer patients administered high dose vitamin C. Overall, vitamin C appears to be a safe and effective adjunctive therapy for acute and chronic pain relief in specific patient groups.

The Therapeutic Effect of Vitamin C in an Animal Model of Complex Regional Pain Syndrome Produced by Prolonged Hindpaw Ischemia-Reperfusion in Rats

Objectives: It is known that increased free radicals from oxidative stress are one of the major causes of complex regional pain syndrome (CRPS). In this study, we tested the hypothesis that vitamin C has a dose-related treatment effect in a chronic post-ischemic pain (CPIP) model. Methods: A total of 49 male rats weighing 250 to 350 g were used. The 4 treatment groups were control (no medication), group 1.0 (administration of 1 mg/day for vitamin C for 5 days), group 2.5 (administration of 2.5 mg/day vitamin C for 5 days), and group 7.5 (administration of 7.5 mg/day vitamin C for 5 days). The 50% mechanical withdrawal threshold and total blood antioxidant status (TAS) were measured before and after administration of vitamin C. Results: Twenty-eight CPIP model rats were generated from 49 rats. Seven rats were randomly allocated to each group. The 50% mechanical withdrawal threshold of group 2.5 (after the administration of vitamin C) was higher than that of the control group and group 1.0 (P < 0.05). At 1 day of the administration of vitamin C, the 50% mechanical withdrawal threshold of group 1.0 was higher than that of the control group and the blood levels of TAS in groups 2.5 and 7.5 were higher than that in control group (P < 0.05). Twelve days after the administration of vitamin C, the blood levels of TAS in groups 2.5 and 7.5 were lower than that of the control group (P < 0.05). Discussion: The administration of a proper dose of vitamin C can reduce oxidative stress, increase antioxidants, and recover the threshold for mechanical allodynia in the CPIP model.

Incidence of Complex Regional Pain Syndrome I Following Foot and Ankle Fractures Using the Budapest Criteria

OBJECTIVE : Fractures are a well-recognized inciting event in the development of complex regional pain syndrome. This study aimed to prospectively determine the incidence of complex regional pain syndrome following foot and ankle fractures. METHODS : A prospective study was conducted of patients presenting to two metropolitan hospitals with plain radiograph diagnosis of fractures to the foot or ankle. Patients were initially screened by phone 3 months after injury using the validated International Association for the Study of Pain Budapest criteria. Patients who fulfilled the screening criteria were then physically examined by a pain specialist to assess clinical signs as part of the Budapest criteria. RESULTS : A total of 306 consecutive eligible patients were included. One hundred and ten patients reported at least one symptom of complex regional pain syndrome; however, only three fulfilled the minimum requirements to necessitate clinical review. Of these three, only one patient fulfilled the combination of symptom and sign criteria for a positive diagnosis according to the validated Budapest criteria. The incidence of complex regional pain syndrome following foot and ankle fracture in this study was 0.3%. CONCLUSION : Although many patients may experience vasomotor, sensory, and sudomotor disturbance following a fracture to the foot and ankle, the observed incidence of complex regional pain syndrome using a prospectively collected validated criteria is significantly lower than previously published.

Work-Related Complex Regional Pain Syndrome: Diagnosis and Treatment

Complex regional pain syndrome can be a debilitating disorder, which, in its earliest stages, can be prevented by aggressive rehabilitation based on reactivation. It is critical to follow international criteria on making the diagnosis; overdiagnosis can lead to inappropriate interventions and further disability. When present, early recognition with reactivation is the cornerstone of treatment. This article presents a phased approach to treatment that suggests movements of nonresponders quickly to more integrated levels of care. Some commonly used invasive interventions, such as sympathectomy and spinal cord stimulation, have not been proved effective; these unproven and potentially harmful therapies should be avoided.

Complications of Distal Radius Fixation

Complications following any form of distal radius fixation remain prevalent. With an armamentarium of fixation options available to practicing surgeons, familiarity with the risks of newer plate technology as it compares with other conventional methods is crucial to optimizing surgical outcome and managing patient expectations. This article presents an updated review on complications following various forms of distal radius fixation.

Complex Regional Pain Type 1

Complex regional pain syndrome is increasingly recognized in the pediatric population. Owing to the nature of presentation with pain, many of these children present to the emergency setting at different stages of the syndrome with or without numerous prior interactions with health professionals. Complex regional pain syndrome type 1 (CRPS1) is a clinical syndrome characterized by amplified musculoskeletal limb pain that is out of proportion to the history and physical findings, or pain due to non-noxious stimuli (allodynia/hyperalgesia), and accompanied by one or more signs of autonomic dysfunction. Differential diagnosis may include significant trauma (eg, fractures), inflammatory conditions, malignancies, and systemic illness. The diagnosis is clinical. The treatment goals for CRPS1 are restoration of function and relief of pain. Education, physical, and occupational therapy with psychotherapy and defined goals of achievement with reward are the mainstay of treatment for this population. Most children with CRPS1 will have a favorable outcome.

Terminology, criteria, and definitions in complex regional pain syndrome: challenges and solutions

Complex regional pain syndrome has long been recognized as a severe and high impact chronic pain disorder. However, the condition has historically been difficult to define and classify and little attention has been given to where complex regional pain syndrome sits within other apparently similar chronic pain disorders, such as fibromyalgia and regional pain syndrome. In this review challenges in regard to nomenclature, definitions, and classification of complex regional pain syndrome are reviewed and suggestions are provided about future directions.

Does vitamin C prevent the occurrence of complex regional pain syndrome in patients with extremity trauma requiring surgery?

The complex regional pain syndrome is a neuroinflammatory pathology that affects the central and peripheral nervous system, characterized by disproportional pain in relation to the trauma experimented by the patient. It has been proposed that vitamin C could prevent the development of this syndrome in patients with limb trauma and surgery. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified two systematic reviews that indentified four primary studies, including one randomized controlled trial. We generated a summary of findings table following the GRADE approach. We concluded it is uncertain whether vitamin C prevents complex regional pain syndrome because the certainty of the evidence is very low.

Management of complications of distal radius fractures

Treating a fracture of the distal radius may require the surgeon to make a difficult decision between surgical treatment and nonsurgical management. The use of surgical fixation has recently increased because of complications associated with conservative treatment. However, conservative action may be necessary depending on certain patient factors. The treating surgeon must be aware of the possible complications associated with distal radius fracture treatments to prevent their occurrence. Prevention can be achieved with a proper understanding of the mechanism of these complications. This article discusses the most recent evidence on how to manage and prevent complications following a fracture of the distal radius.

Management and complications of traumatic peripheral nerve injuries

This article provides an overview of the management of traumatic peripheral nerve injuries. It examines the basic pathophysiology of peripheral nerve injuries, along with the clinical presentation, diagnostic work-up, and treatment options and outcomes for the various classifications of traumatic peripheral nerve injuries.

Vitamin supplementation as possible prophylactic treatment against migraine with aura and menstrual migraine

Migraine is the most common form of headache disorder globally. The etiology of migraine is multifactorial, with genetic components and environmental interactions considered to be the main causal factors. Some researchers postulate that deficits in mitochondrial energy reserves can cause migraine or an increase in homocysteine levels can lead to migraine attacks; therefore, vitamins could play a vital role in migraine prevention. For instance, riboflavin influences mitochondrial dysfunction and prevents migraine. Genes such as flavoenzyme 5,10-methylenetetrahydrofolate reductase (MTHFR), especially the C677T variant, have been associated with elevated plasma levels of homocysteine and migraine with aura. Homocysteine catalyzation requires the presence of vitamins B₆, B₁₂, and folic acid, which can decrease the severity of migraine with aura, making these vitamins potentially useful prophylactic agents for treating migraine with aura. Menstrual migraine, on the other hand, is associated with increased prostaglandin (PG) levels in the endometrium, indicating a role for vitamin E, which is an anti-PG. Vitamin C can also be used as a scavenger of reactive oxygen species for treating neurogenic inflammation in migraine patients. This paper reviews possible therapies based on vitamin supplementation for migraine prophylaxis, focusing on migraine with aura and menstrual migraine.

The complex regional pain syndrome

Complex regional pain syndrome (CRPS) is the current consensus-derived name for a syndrome usually triggered by limb trauma. Required elements include prolonged, disproportionate distal-limb pain and microvascular dysregulation (e.g., edema or color changes) or altered sweating. CRPS-II (formerly "causalgia") describes patients with identified nerve injuries. CRPS-I (formerly "reflex sympathetic dystrophy") describes most patients who lack evidence of specific nerve injuries. Diagnosis is clinical and the pathophysiology involves combinations of small-fiber axonopathy, microvasculopathy, inflammation, and brain plasticity/sensitization. Females have much higher risk and workplace accidents are a well-recognized cause. Inflammation and dysimmunity, perhaps facilitated by injury to the blood-nerve barrier, may contribute. Most patients, particularly the young, recover gradually, but treatment can speed healing. Evidence of efficacy is strongest for rehabilitation therapies (e.g., graded-motor imagery), neuropathic pain medications, and electric stimulation of the spinal cord, injured nerve, or motor cortex. Investigational treatments include ketamine, botulinum toxin, immunoglobulins, and transcranial neuromodulation. Nonrecovering patients should be re-evaluated for neurosurgically treatable causal lesions (nerve entrapment, impingement, infections, or tumors) and treatable potentiating medical conditions, including polyneuropathy and circulatory insufficiency. Earlier impressions that CRPS represents malingering or psychosomatic illness have been replaced by evidence that CRPS is a rare complication of limb injury in biologically susceptible individuals.

Factors associated with complex regional pain syndrome type I in patients with surgically treated distal radius fracture

PURPOSE

Wrist fracture is considered a typical initiating trauma for complex regional pain syndrome type I (CRPS I). However, few studies have comprehensively evaluated factors associated with the occurrence of CRPS I after the surgical treatment of a distal radius fracture (DRF). This study evaluates the factors influencing the occurrence of CRPS I after the surgical treatment of a DRF.

METHODS

A total of 477 patients with a DRF who had been treated surgically were enrolled in this prospective observational study. Patients were followed for 6 months after surgery, and CRPS I was diagnosed using the Budapest diagnostic criteria for research. The factors assessed for the development of CPRS I were age, gender, the body mass index, the type of fracture, the energy of trauma, the number of trial reductions, the type of surgery, and the duration of immobilization. A multivariate logistic regression analysis was conducted to identify independent predictors of the occurrence of CRPS I.

RESULTS

Among the 477 patients, 42 (8.8 %) satisfied the Budapest criteria for CRPS I within 6 months of surgery. Female patients developed CRPS I more frequently, and the patients who developed CRPS I were older and more likely to sustain a high energy injury or have a comminuted fracture. According to the multivariate analysis, female patients and those with a high energy trauma or severe fracture type were significantly more likely to develop CRPS I (p = 0.02, 0.01, and 0.01, respectively).

CONCLUSIONS

High energy injuries, severe fractures, and the female gender contribute to the development of CRPS I after the surgical treatment of DRF. The results have important implications for physicians who wish to identify patients at high risk for CRPS I after operative fixation for DRF and instigate treatment accordingly.

Testing the validity of preventing chronic regional pain syndrome with vitamin C after distal radius fracture. [Corrected]

PURPOSE

The American Academy of Orthopaedic Surgeons recommends the use of vitamin C to prevent complex regional pain syndrome (CRPS) for patients with distal radius fractures (DRFs). We hypothesized that the evidence for supporting this recommendation is weak, based on epidemiological principles of association and causality. The specific aim of this project was to test the validity of this recommendation.

METHODS

We conducted a literature review to retrieve articles reporting on the use of vitamin C to prevent CRPS. Data collected included sample size, study design type, dose of vitamin C used, and outcome measures of association expressed as relative risk (RR) and odds ratio. We then applied Hill criteria to evaluate the relationship between vitamin C and CRPS.

RESULTS

We obtained 225 articles from the database search. After the exclusion of duplicates, unrelated articles, editorial letters, and commentaries, we found 4 articles and 1 systematic review relevant to our topic. Six of the 9 Hill criteria were met, and an earlier meta-analysis showed a quantified reduction in CRPS risk. However, criteria like biological plausibility, specificity, and coherence were not met.

CONCLUSIONS

The number of causal/association criteria met was adequate to support the scientific premise of the effect of vitamin C in preventing CRPS after DRF. Furthermore, vitamin C administration is of relatively low cost and has few complications unless administered in large doses. Owing to sufficient epidemiological evidence availability, the American Academy of Orthopaedic Surgeons recommendation of vitamin C to prevent CRPS has practical merit.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Controversies in the management of distal radius fractures

Controversies span the entire spectrum of management of distal radius fractures-fracture assessment, diagnosis, treatment, and evaluation of outcomes. The utility of multiple radiographic views described in the literature has not been validated. Likewise, the several classification systems that exist have yet to demonstrate substantial interobserver and intraobserver reliability. Nonsurgical controversies involve fracture reduction, use of anesthesia, type of fracture immobilization, and forearm position during healing. Surgical controversies include surgical indications, need for release of carpal tunnel, fracture fixation method, and the need for augmentation (ie, bone graft). Postoperatively, rehabilitation, medication, and physical therapy also remain highly controversial. The best outcome measure has yet to be established. A strong need remains for high-level, prospective studies to determine the most effective way to assess, diagnose, treat, and measure outcomes in patients with distal radius fractures.

Redox regulation of neuronal voltage-gated calcium channels

SIGNIFICANCE

Voltage-gated calcium channels are ubiquitously expressed in neurons and are key regulators of cellular excitability and synaptic transmitter release. There is accumulating evidence that multiple subtypes of voltage-gated calcium channels may be regulated by oxidation and reduction. However, the redox mechanisms involved in the regulation of channel function are not well understood.

RECENT ADVANCES

Several studies have established that both T-type and high-voltage-activated subtypes of voltage-gated calcium channel can be redox-regulated. This article reviews different mechanisms that can be involved in redox regulation of calcium channel function and their implication in neuronal function, particularly in pain pathways and thalamic oscillation.

CRITICAL ISSUES

A current critical issue in the field is to decipher precise mechanisms of calcium channel modulation via redox reactions. In this review we discuss covalent post-translational modification via oxidation of cysteine molecules and chelation of trace metals, and reactions involving nitric oxide-related molecules and free radicals. Improved understanding of the roles of redox-based reactions in regulation of voltage-gated calcium channels may lead to improved understanding of novel redox mechanisms in physiological and pathological processes.

FUTURE DIRECTIONS

Identification of redox mechanisms and sites on voltage-gated calcium channel may allow development of novel and specific ion channel therapies for unmet medical needs. Thus, it may be possible to regulate the redox state of these channels in treatment of pathological process such as epilepsy and neuropathic pain.

Health services research: evolution and applications

Health services research (HSR) is broadly focused on characterizing and improving the access, quality, delivery, and cost of health care. HSR is a multidisciplinary field, engaging experts in clinical medicine and surgery, policy, economics, implementation science, statistics, psychology, and education to improve the care of patients across all specialties. This article summarizes the evolution and distinctive attributes of HSR and present several real-world applications.

Complex regional pain syndrome: From diagnosis to rehabilitation

Complex regional pain syndrome (CRPS) is a debilitating pathology characterised by intense chronic pain associated with vasomotor, sensory and motor dysfunction of the affected limb. Although the pathophysiology of CRPS is not fully understood, it is recognised that inflammatory processes and autonomic dysfunction are involved. These processes are associated with peripheral and central sensitisation as well as changes in brain structure and function, and are reflected in the clinical presentation of CRPS. CRPS management requires an interdisciplinary team and requires the therapeutic approach to be individualised. With regard to pharmacological treatment, bisphosphonates, corticosteroids, ketamine and anticonvulsants have been demonstrated to be effective for CRPS management. Psychotherapy, including cognitive-behavioural therapy, has produced promising results but more studies are needed to confirm its efficacy. Among rehabilitation interventions, there is evidence of the efficacy of physiotherapy and occupational therapy in diminishing CRPS symptoms and achieving a higher level of functioning. In this regard, the rehabilitation modality that seems the most promising according to the actual literature is graded motor imagery, which can help to reverse the maladaptive neuroplasticity occurring in CRPS.