Post-traumatic complex regional pain syndrome: clinical features and epidemiology

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

CONCLUSION

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

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.

The Evidence for Perioperative Anesthetic Techniques in the Prevention of New-Onset or Recurrent Complex Regional Pain Syndrome in Hand Surgery

Complex regional pain syndrome (CRPS) is a multifaceted condition characterized by chronic neuropathic pain, allodynia, and hyperalgesia. The incidence of CRPS postoperatively is alarmingly high, particularly following carpal tunnel surgeries, Dupuytren's fasciectomy, and repairs of wrist and hand fractures, with recurrence rates soaring in individuals with a history of CRPS. Despite extensive research, the management of CRPS remains complicated, highlighting the urgent need for effective prevention strategies. This scoping review aimed to consolidate current evidence surrounding the efficacy of perioperative anesthetic techniques in preventing new-onset or recurrent CRPS, focusing on the application of various anesthetic interventions. Through a comprehensive literature search, eight articles were identified, discussing a spectrum of techniques, including wide awake local anesthesia no tourniquet (WALANT) and various regional blockade methods. This review revealed that the WALANT technique, with its simplicity and lower costs, exhibited promising results in preventing CRPS. Conversely, techniques involving intravenous regional and axillary plexus blocks showed variable efficacy, necessitating further investigation. The scarcity of high-quality evidence underscores the critical need for meticulously designed, large-scale randomized controlled trials to validate these findings and explore the potential of stellate ganglion block in the prevention of recurrent CRPS.

A case-control study on the effect of rhythmic masticatory muscle activity (RMMA) clusters on sleep fragmentation and severity of orofacial muscle pain in sleep bruxism

Rhythmic masticatory muscle activity (RMMA) is a periodic muscle activity that characterises sleep bruxism (SB) events. These can occur as a single event, in pairs, or in clusters. Since RMMA episodes often occur in clusters and the relevance of this occurrence is unknown, we conducted a study to investigate the effect of RMMA clusters on sleep fragmentation and the severity of orofacial muscle pain. This study involved a secondary analysis using data from 184 adult subjects with orofacial muscle pain who underwent definitive polysomnography (PSG) for sleep bruxism diagnosis. Self-reported orofacial muscle pain (OFMP) was assessed using the numeric rating scale, and additional evaluation of side-to-side equivalence (symmetry) was described using a binary system. Among the 184 participants, 60.8% (n = 112) did not exhibit clusters and among the 72 participants with clusters, 36.1% (n = 26) and 63.9% (n = 46) were in the high and low RMMA frequency groups, respectively. The high SB group had significantly three times more phasic RMMA events than the noncluster group. A total of 89.67% (n = 165) of subjects reported orofacial muscle pain. While there was no difference in the severity of OFMP among groups, a significant decrease in symmetry between the severity of temporal muscle pain on the left and right sides was noted in the cluster group compared with the noncluster group. Clustering of RMMA events is associated with sleep fragmentation. The asymmetry of temporal muscle pain is related to the presence of RMMA clusters in sleep bruxism.

A Decade of Complex Regional Pain Syndrome Following Orthopedic Wrist Surgery: A Case Report and a Literature Review

Every day, people of all ages in the United States break bones, with traumatic injury being the most common way, and wrist injury being in the top five most common areas in which bones break. Traumatic fractures are managed with either surgical or nonsurgical approaches. The surgical approach utilizes ortho procedures such as internal fixation and reduction, while the nonsurgical approach consists of procedures like RICE, ace bandage, and so on. However, in rare cases, patients are left with a peculiar constellation of symptoms, which cause edema, pain, skin changes, and loss of function at the trauma site. This occurrence is termed complex regional pain syndrome. Here, we present the case of a 55-year-old female patient who suffered a traumatic wrist injury. The trauma was fixed by pinning ORIF orthopedic surgery, and the patient developed manifestations of complex regional pain syndrome around 10 days postoperatively. In this case report, we describe the variation and complexity of symptoms in the patient over the course of a decade after the original injury. The case report explains the pain management therapies that reduced the patient's symptoms and highlights the ones that were ineffective. We have included some less frequently used yet effective treatments and shed light on how this disease affected the patient's overall well-being.

Patient satisfaction with virtual evaluation, diagnosis, and treatment of CRPS

Background

The COVID-19 pandemic has led to an increased reliance on virtual care in the rehabilitation setting for patients with conditions such as complex regional pain syndrome (CRPS).

Aims

The aim of this study was to perform a quality improvement initiative to assess patient satisfaction and ensure that outcomes following virtual assessment, diagnosis, and treatment of CRPS with prednisone are safe and effective.

Methods

An online survey was distributed to 18 patients with CRPS who had been seen virtually between March and December 2020 through a rehabilitation clinic and treated with oral prednisone. Thirteen participants completed the survey, which was designed de novo by our team to evaluate participant perceptions and satisfaction regarding the virtual care experience. Also included in the survey was a CRPS-specific validated patient-report questionnaire (Hamilton Inventory for CRPS: PR-HI-CRPS), which allowed participants to describe their specific symptoms and associated functional and psychosocial impacts, both previously (pretreatment baseline) and at the time of survey (posttreatment).

Results

CRPS symptoms and related impacts were scored as significantly improved from baseline following treatment with prednisone. Likert scale results from survey responses related to patients' experiences and satisfaction with the virtual care process were analyzed; the majority of patients reported satisfaction with a virtual appointment for evaluation of CRPS, as well as with subsequent treatment decisions based on virtual assessment.

Conclusions

This quality improvement study suggests that virtual care is a potential option for a patient-accepted approach to overcoming challenges with in-person care imposed by the COVID-19 pandemic and could help inform future considerations in addressing geographic and patient-specific disparities in access to specialist care for CRPS.

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.

Anesthetic Management of a Complex Regional Pain Syndrome (CRPS) Patient With Ketamine

Complex regional pain syndrome (CRPS) is a potentially debilitating form of neuropathic pain that may manifest following a traumatic injury or surgery. CRPS is also known as algodystrophy, causalgia, or reflex sympathetic dystrophy (RSD). Patients describe unbearable burning pain from nonnociceptive stimuli, such as when taking a shower or brushing against another object. Regular tactile stimuli encountered during routine dental procedures may not be well-tolerated by a patient with CRPS. Ketamine infusions have been reported to help alleviate acute exacerbations or "flare-ups" of CRPS symptoms. This case report provides a brief overview of CRPS pathophysiology and treatment including data supporting the use of ketamine infusions and a discussion regarding the anesthetic management of a patient with CRPS presenting for dental care under deep sedation utilizing high-dose intravenous ketamine.

Complex Regional Pain Syndrome Caused by an Axillary Lipoma

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy syndrome, is a rare chronic neuro-inflammatory pain condition, which can follow a soft-tissue, bone (type I), or nerve injury (type II) that can be severe and often lasts longer than the original tissue damage. Lipomas impinging on the brachial plexus are rare. To date, there have been no documented cases of CRPS caused by a benign tumor. Here, we report a rare case of CRPS caused by surgical removal of a left axillary lipoma impinging on the brachial plexus. The patient presented with neuropathic pain and hyperalgesia of the left arm, in a non-dermatomal pattern, and pain out of proportion to touch and painful stimulus. Persistent CRPS continued to occur post-operatively for one year without significant change in her pain characteristics. CRPS following elective or emergent surgery to the extremities can pose significant complications to recovery and post-operative care. This condition can be induced through surgery or trauma, which can complicate recovery, impair motor functionality, and cause debilitating pain. Treatment modalities and pathogenesis for CRPS remain obscure and limited, which leads to wide misdiagnosis. Our case highlights the importance of considering CRPS when evaluating differential diagnoses for pre- and post-operative conditions affecting the upper and lower extremities.

Radiographic evaluation of vascularity in scaphoid nonunions: A review

Scaphoid fractures, particularly those that occur more proximally, are unreliable in achieving union due to the retrograde blood supply of the scaphoid bone. Vascular compromise is associated with the development of nonunions and avascular necrosis of the proximal pole. Due to the tenuous blood supply of the scaphoid, it is imperative that the vascularity be assessed when creating diagnostic and treatment strategies. Early detection of vascular compromise via imaging may signal impending nonunion and allow clinicians to perform interventions that aid in restoring perfusion to the scaphoid. Vascular compromise in the scaphoid presents a diagnostic challenge, in part due to the non-specific findings on plain radiographs and computed tomography. Magnetic resonance imaging techniques have dramatically improved our ability to assess the blood supply to the scaphoid and improve time to intervention. This review aims to summarize these advances and highlights the importance of imaging in assessing vascular compromise in scaphoid nonunion and in reperfusion following surgical intervention.

Neuromodulation of the Dorsal Root Ganglion for Chronic Postsurgical Pain

Objective

The objective of this study is to review the available evidence for dorsal root ganglion (DRG) stimulation for the treatment of complex regional pain syndrome type II (CRPS II; peripheral causalgia) associated with chronic neuropathic postsurgical pain (NPP).

Design

Available literature was identified through a search of the US National Library of Medicine’s Medline database, PubMed.gov. References from published articles also were reviewed for relevant citations.

Results

The data published to date support the use of DRG stimulation to treat chronic NPP of the groin, knee, and foot. NPP following procedures such as thoracotomy, hernia surgery, and knee replacement surgery were identified as some of the conditions for which DRG stimulation is likely to be effective.

Conclusion

DRG stimulation is known to be an effective treatment for focal neuropathic pain. Currently, NPP of the foot, groin, and knee all appear to be the conditions with the most clinical experience, backed by a limited but growing body of evidence. However, prospective studies lag behind real-world clinical experience and are needed to confirm these findings.