Treatment of complex regional pain syndrome type I with bisphosphonates

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Structural insights into the binding of zoledronic acid with RANKL via computational simulations

Zoledronic acid (ZOL) inhibits receptor activator of nuclear factor-κB ligand (RANKL) and reduces bone turnover. This plays an important role in the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). Previous reports have shown that ZOL binds to the enzyme farnesyl pyrophosphate synthase (FPPS) to block its activity. However, the mechanism of action of ZOL and its interaction with RANKL is still unclear. In this study, we confirmed that ZOL significantly suppressed the bone remodeling in ZOL-treated rats, investigated whether ZOL could bind to RANKL and examined the interactions between these molecules at the atomic level. Surface plasmon resonance (SPR) assay was performed to validate that ZOL could directly bind to RANKL in a dose dependent manner, and the equilibrium constant was calculated (K_D = 2.28 × 10⁻⁴ M). Then, we used molecular docking simulation to predict the binding site and analyze the binding characteristics of ZOL and RANKL. Through molecular dynamics simulation, we confirmed the stable binding between ZOL and RANKL and observed their dynamic interactions over time. Binding free energy calculations and its decomposition were conducted to obtain the binding free energy −70.67 ± 2.62 kJ/mol for the RANKL–ZOL complex. We identified the key residues of RANKL in the binding region, and these included Tyr217(A), Val277(A), Gly278(A), Val277(B), Gly278(B), and Tyr215(C). Taken together, our results demonstrated the direct interaction between ZOL and RANKL, indicating that the pharmacological action of ZOL might be closely related to RANKL. The design of novel small molecules targeting RANKL might reduce the occurrence of BRONJ.

Bone Involvement in Patients with Spondyloarthropathies

Spondyloarthropathies (SpA) are common systemic inflammatory rheumatic diseases, in which, as in other rheumatic diseases, levels of markers of bone resorption are elevated, leading to bone loss and elevated risk of vertebral fractures. However, the diseases are also associated with new bone formation in the spine, the so-called syndesmophytes. We tried to unravel the pathogenesis of formation and growth of syndesmophytes and evaluated new diagnostic and treatment options. After a successful meeting of the Working Group on Rheumatic Diseases at the ECTS 2020, we (WL and CR) were excited about the quality of the speakers (CM, JH, AG, and GL) and their complimentary lectures. Given the relative lack of reviews on spondyloarthropathies and bone, we decided to work together on a comprehensive review that might be interesting for basic scientists and clinically relevant for clinicians. Radiographic progression in axSpA is linked to several risk factors, like male sex, smoking, HLA-B-27, increased levels of CRP, presence of syndesmophytes, and marked inflammation on MRI. The potential role of mechanical stress in the context of physically demanding jobs has been also suggested to promote structural damages. Different treatment options from NSAIDs to biologic agents like TNF inhibitors (TNFi) or IL-17inhibitors (IL-17i) result in a reduction of inflammation and symptoms. However, all these different treatment options failed to show clear and reproducible results on inhibition on syndesmophyte formation. The majority of data are available on TNFi, and some studies suggested an effect in subgroups of patients with ankylosing spondylitis. Less information is available on NSAIDs and IL-17i. Since IL-17i have been introduced quite recently, more studies are expected. IL-17 inhibitors (Il-17i) potently reduce signs and symptoms, but serum level of IL-17 is not elevated, therefore, IL-17 probably has mainly a local effect. The failure of anti-IL-23 in axSpA suggests that IL-17A production could be independent from IL-23. It may be upregulated by TNFα, resulting in lower expression of DKK1 and RANKL and an increase in osteogenesis. In active AS markers of bone resorption are increased, while bone formation markers can be increased or decreased. Bone Turnover markers and additional markers related to Wnt such as DKK1, sclerostin, and RANKL are valuable for elucidating bone metabolism on a group level and they are not (yet) able to predict individual patient outcomes. The gold standard for detection of structural lesions in clinical practice is the use of conventional radiographics. However, the resolution is low compared to the change over time and the interval for detecting changes are 2 years or more. Modern techniques offer substantial advantages such as the early detection of bone marrow edema with MRI, the fivefold increased detection rate of new or growing syndesmophytes with low-dose CT, and the decrease in 18F-fluoride uptake during treatment with TNFα-inhibitors (TNFi) in a pilot study in 12 AS patients. Detection of bone involvement by new techniques, such as low-dose CT, MRI and 18-Fluoride PET-scans, and bone turnover markers, in combination with focusing on high-risk groups such as patients with early disease, elevated CRP, syndesmophytes at baseline, male patients and patients with HLA-B27 + are promising options for the near future. However, for optimal prevention of formation of syndesmophytes we need more detailed insight in the pathogenesis of bone formation in axSpA and probably more targeted therapies.

Hypnotherapy for complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is a chronic, disabling condition with prolonged or excessive pain persisting in a limb usually following a triggering injury or trauma to an extremity. The subjective expression of pain is disproportionate to what would be objectively expected from the initial injury. It may also be accompanied by a variety of autonomic disturbances and trophic abnormalities such as swelling in the affected area and changes in skin color and temperature. Understanding the pathophysiology of CRPS remains a medical challenge, along with making the diagnosis and devising an effective treatment plan. There are limited randomized controlled trials and definitive treatment is yet to evolve for this life-altering condition. This case study illustrates the safe, cost-effective addition and efficacious use of hypnosis in the integrative treatment plan for a teenager with CRPS.

Complex Regional Pain Syndrome: A Comprehensive Qualitative Research Study on Unmet Needs in the "Patient Journey"

Purpose

This qualitative research study aimed to characterize the "patient journey" for patients with complex regional pain syndrome (CRPS) and identify the unmet needs related to the management and treatment of the condition for healthcare providers (HCPs), patients, and their caregivers.

Materials and Methods

Multifaceted, dynamic methodology, iteratively gathering cognitive, emotional and social insights, was used to support and conduct in-depth, immersion interviews across the USA with 59 HCPs in-office and in roundtable discussions, and 20 patient-support partner dyads in-home.

Results

Patients were aged >18 years, primarily female, and all were diagnosed with CRPS (limited to type 1 in this patient cohort). Results show that the current state of CRPS treatment may fall short in multiple key areas. In some cases, poor awareness of CRPS causes delayed diagnoses impacting the opportunity for early treatment, resulting in long-term poor health outcomes. Consequently, the CRPS "patient journey" may be characterized by clinical frustration of physicians and disappointment for some patients. The poor treatment experiences and outcomes for some patients and HCPs may build the perception of a non-collaborative relationship. HCPs and patients agree that an effective treatment would be one that addresses CRPS rather than its symptoms, and the availability of such an option would transform the treatment experience.

Conclusion

CRPS leads to cognitive, social and emotional burdens for patients and their caregivers. There is an unmet need for improved CRPS disease awareness and successful therapeutic options to aid in earlier diagnoses, effective treatment and better outcomes for HCPs, patients, and their caregivers.

Complex regional pain syndrome and bone marrow oedema syndrome: family ties potentially closer than expected

Complex regional pain syndrome (CRPS) and bone marrow edema syndrome (BMES) are two rare conditions that are still being discussed. They are generally considered as two distinct entities, yet they share similarities such as a homogeneous bone marrow edema is also often found in the early phase of CRPS. We present the case of a 41-year-old man with CRPS after a foot fracture followed by the development of painful BMES of the ipsilateral knee and hip a few weeks later. The search for another pathology was negative. After pamidronate infusions, the evolution was spectacular: the disappearance of hip pain at 1 month and more than 50% reduction in knee and foot pain at 2 months. At final follow-up (1 year), the patient was asymptomatic. This case reinforces the idea of a possible link between CRPS and BMES probably through similar trabecular bone involvement. Imaging remains useful in diagnosis of CRPS.

Regeneration of Cochlear Synapses by Systemic Administration of a Bisphosphonate

Sensorineural hearing loss (SNHL) caused by noise exposure and attendant loss of glutamatergic synapses between cochlear spiral ganglion neurons (SGNs) and hair cells is the most common sensory deficit worldwide. We show here that systemic administration of a bisphosphonate to mice 24 h after synaptopathic noise exposure regenerated synapses between inner hair cells and SGNs and restored cochlear function. We further demonstrate that this effect is mediated by inhibition of the mevalonate pathway. These results are highly significant because they suggest that bisphosphonates could reverse cochlear synaptopathy for the treatment of SNHL.

Spinal cord stimulation for the treatment of complex regional pain syndrome leads to improvement of quality of life, reduction of pain and psychological distress: a retrospective case series with 24 months follow up

Background and aims

Complex regional pain syndrome (CRPS) is a common pain condition which is characterized by pain, functional impairment, and trophic changes. Neurosurgical treatment is not widely offered. In this study the treatment with spinal cord stimulation (SCS) was evaluated over 24 months follow up.

Methods

A retrospective case analysis of six patients with severe CRPS was performed. Pain chronicity was recorded with the Mainz Pain Staging System (MPSS). Pain intensity (NRS), activity level and health-related quality of life (EQ-5D-5L), the actual mood state (ASTS), and treatment satisfaction (CSQ-8) were assessed. All patients received conventional pharmacological treatments including multimodal pain therapy through their local pain therapist or in specialized centers as well as physical therapy. A SCS electrode was implanted for trial stimulation. After successful trial a neurostimulator was implanted and connected to the electrode. Patients were retrospectively analyzed before implantation and 6, 12 and 24 months postoperatively. Statistical analysis was performed using Mann–Whitney U and Wilcoxon rank-sum test.

Results

Patients median age was 43 years (IQR25−75 37–43 years). The median MPSS Score was 3 of 3 indicating a high pain chronicity. Median NRS before implantation of the neurostimulator was 8.8 (IQR25−75 7.6–9.3). A reduction to 7.8 (IQR25−75 4.8–8.1; p = 0.14) after 6 months, 6.5 (IQR25−75 3.8–8.1; p = 0.08) after 1 year, and 6.8 (IQR25−75 3.8–8.5; p = 0.15) after 2 years was achieved. Median EQ-5D-5L index value before treatment was 0.27 (IQR25−75 0.25–0.41) indicating a severely lowered quality of life. A significant improvement to 0.53 (IQR25−75 0.26–0.65; p = 0.03) after 6 months, 0.58 (IQR25−75 0.26–0.84; p = 0.03) after 1 year as well as after 2 years was seen. ASTS scale showed an increase of values for positive mood, and a reduction in values for sorrow, fatigue, anger and desperation during the whole follow up period. The treatment satisfaction in the whole cohort with a median CSQ-8 value of 29.5 of 32 was very high.

Conclusion

The results of this small case series showed a significant improvement of the EQ-5D-5L after implantation of a neurostimulator. NRS reduction was not significant but a clear tendency towards reduced values was observed. We therefore conclude that SCS is an alternative option to relieve chronic pain and psychological distress originating from CRPS if non-invasive managements of severe CRPS failed. The preoperative selection plays a crucial role for good results.

Implications

CRPS is difficult to treat. SCS is an alternative option to improve the quality of life and relieve chronic pain originating from severe CRPS if conservative treatment modalities fail. Further psychological distress is reduced in long-term follow up. SCS should be kept in mind for therapy refractory cases.

Bone microstructure is significantly altered in CRPS-affected distal tibiae as detected by HR-pQCT: a retrospective cross-sectional study

In the course of complex regional pain syndrome (CRPS), local osteopenia in the subchondral/subcortical areas of the affected limb represents a central manifestation. Mechanistic aspects of CRPS-associated pathologies remain unclear, and knowledge about bone morphology in CRPS-affected areas is rare. The aim of this study was to assess trabecular and cortical bone microstructure in patients with CRPS of the distal tibiae. We retrospectively analysed 14 women diagnosed with unilateral CRPS type I of the lower limb whose affected and unaffected distal tibiae were examined by high-resolution peripheral quantitative computed tomography (HR-pQCT). Laboratory tests included serum levels of calcium, phosphate, 25-hydroxyvitamin D, bone alkaline phosphatase, parathyroid hormone, osteocalcin and urinary levels of deoxypyridinoline (DPD). Bone mineral density was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and both proximal femurs. Average urinary DPD levels, a biochemical marker of bone resorption, were elevated in the examined patient cohort (7.1 ± 1.9 nmol/mmol, reference 3.0-7.0 nmol/mmol). According to HR-pQCT, CRPS-affected distal tibiae showed significantly lower values of cortical BMD and cortical thickness compared to the unaffected contralateral side. Also, bone volume relative to total volume was significantly lower. Trabecular number and trabecular thickness tended to be lower in the affected tibiae. CRPS is associated with significant alterations in bone microstructure of the affected tibiae. Increased bone resorption seems to play a crucial role within a multifactorial process of CRPS-mediated bone atrophy. HR-pQCT could possibly serve as a diagnostic tool in specific CRPS therapy.

Neuropathic Pain

PURPOSE OF REVIEW

Neuropathic pain is a frequently encountered condition that is often resistant to treatment and is associated with poor patient satisfaction of their treatment. Several medications have been shown to be effective in treating neuropathic pain associated with diabetic neuropathy and postherpetic neuralgia, and these medications are often used to treat neuropathic pain associated with other conditions as well. This article summarizes the diagnosis and assessment of patients with neuropathic pain as well as available pharmacologic and interventional treatment options.

RECENT FINDINGS

Evidence-based recommendations for the treatment of neuropathic pain have been published, and first-line medications include antidepressants, anticonvulsants, topical agents, as well as opioid analgesics. Interventional options include anesthetic and steroid injections, nerve blocks, and spinal cord stimulation. Essential to the treatment algorithm of neuropathic pain is the assessment and treatment of psychosocial comorbidities and the utilization of a multidisciplinary team approach, including cognitive-behavioral and rehabilitative therapies. Questions remain about the comparative effectiveness of various medications and combination therapies. Increasing interest also exists in the optimization and personalization of pharmacotherapy based upon the underlying mechanism(s) of neuropathic pain according to the quality of the patient's symptoms.

SUMMARY

The management of chronic neuropathic pain is challenging and is best achieved with the use of a multidisciplinary team. Pain is a subjective experience, and it is important to validate a patient's pain, address psychosocial comorbidities, and set realistic treatment goals. Evidence-based guidelines are available to guide treatment, but frequently, high-quality evidence-based recommendations are lacking.

Novel Pharmacological Nonopioid Therapies in Chronic Pain

PURPOSE OF REVIEW

Opioid use and abuse has led to a worldwide opioid epidemic. And while opioids are clinically useful when appropriately indicated, they are associated with a wide range of dangerous side effects and whether they are effective at treating or eliminating chronic pain is controversial. There has long been a need for the development of nonopioid alternative treatments for patients that live in pain, and until recently, only a few effective treatments were available. Today, there are a wide range of nonopioid treatments available including NSAIDs, acetaminophen, corticosteroids, nerve blocks, SSRIs, neurostimulators, and anticonvulsants. However, these treatments are still not entirely effective at treating pain, which has sparked a new exploration of novel nonopioid pharmacotherapies.

RECENT FINDINGS

This manuscript will outline the most recent trends in novel nonopioid pharmacotherapy development including tramadol/dexketoprofen, TrkA inhibitors, tapentadol, opioid agonists, Nektar 181, TRV 130, ßarrestin2, bisphosphonates, antibodies, sodium channel blockers, NMDA antagonists, TRP receptors, transdermal vitamin D, AAK1 kinase inhibition, calcitonin gene-related peptide (CGRP), TRPV4 antagonists, cholecystokinin, delta opioid receptor, neurokinin, and gene therapy. The pharmacotherapies discussed in this manuscript outline promising opioid alternatives which can change the future of chronic pain treatment.

Evaluation of bone microstructure in CRPS-affected upper limbs by HR-pQCT

INTRODUCTION

Complex regional pain syndrome (CRPS) is a major complication after trauma, surgery, and/or immobilization of an extremity. The disease often starts with clinical signs of local inflammation and develops into a prolonged phase that is characterized by trophic changes and local osteoporosis and sometimes results in functional impairment of the affected limb. While the pathophysiology of CRPS remains poorly understood, increased local bone resorption plays an undisputed pivotal role. The aim of this retrospective clinical study was to assess the bone microstructure in patients with CRPS.

METHODS

Patients with CRPS type I of the upper limb whose affected and unaffected distal radii were analyzed by high-resolution peripheral quantitative computed tomography (HR-pQCT) were identified retrospectively. The osteology laboratory data and dual-energy X-ray absorptiometry (DXA) images of the left femoral neck and lumbar spine, which were obtained on the same day as HR-pQCT, were extracted from the medical records.

RESULTS

Five patients were identified. The CRPS-affected upper limbs had significantly lower trabecular numbers and higher trabecular thicknesses than the unaffected upper limbs. However, the trabecular bone volume to total bone volume and cortical thickness values of the affected and unaffected sides were similar. Trabecular thickness tended to increase with time since disease diagnosis.

DISCUSSION

CRPS associated with significant alterations in the bone microstructure of the affected upper limb that may amplify as the duration of disease increases.

Demystifying Poststroke Pain: From Etiology to Treatment

Pain after stroke is commonly reported but often incompletely managed, which prevents optimal recovery. This situation occurs in part because of the esoteric nature of poststroke pain and its limited presence in current discussions of stroke management. The major specific afflictions that affect patients with stroke who experience pain include central poststroke pain, complex regional pain syndrome, and pain associated with spasticity and shoulder subluxation. Each disorder carries its own intricacies that require specific approaches to treatment and understanding. This review aims to present and clarify the major pain syndromes that affect patients who have experienced a stroke in order to aid in their diagnosis and treatment.

New Chronic Pain Treatments in the Outpatient Setting: Review Article

Chronic pain is an issue encountered by many health care providers in their routine clinical practice. In addition to generalized patient suffering, this condition has significant clinical, psychological, and socioeconomic impact due to its widespread occurrence. The landscape of chronic pain management has been changing rapidly with an array of treatment innovations, better understanding of established therapies, and care coordination across specialties. In this article, we have reviewed emerging new modalities as well as transformation of established therapies by interventional, pharmacologic, rehabilitative, psychological, complimentary, and interdisciplinary approaches.

Adult Complex Regional Pain Syndrome Type I: A Narrative Review

Complex regional pain syndrome type I (CRPS I) is a multifactorial painful disorder with a complex pathogenesis. Both peripheral and central mechanisms are involved. Acute CRPS I is considered to be an exaggerated inflammatory disorder; however, over time, because of altered function of the sympathetic nervous system and maladaptive neuroplasticity, CRPS I evolves into a neurological disorder. This review thoroughly describes the pathophysiological aspects of CRPS I and summarizes the potential therapeutic options. The mechanisms and targets of the treatment are different in the early and late stages of the disease. This current review builds on a previous review by this author group by deepening the role of the peripheral classic and neuronal inflammatory component in the acute stage of this painful disorder.

LEVEL OF EVIDENCE

Not applicable.

The Pharmacological Management of Complex Regional Pain Syndrome in Pediatric Patients

The awareness of complex regional pain syndrome (CRPS) in the pediatric population is increasing. The condition involves regional pain that is out of proportion to any initiating event (if there is one) and is associated with sensory, functional, autonomic, and inflammatory changes in the region of the pain. The signs and symptoms of CRPS can vary between patients and stage of the disease process. Like many chronic pain conditions, it is often associated with significant disability and a detrimental effect on quality of life. It has a complex pathophysiology that remains poorly understood but provides many potential targets for treatments. Management involves a biopsychosocial formulation that encompasses physical and psychological interventions alongside pharmacological strategies. We review the current evidence for the treatment of this condition in children, with particular reference to pharmacological management.