Validation of proposed diagnostic criteria (the "Budapest Criteria") for Complex Regional Pain Syndrome

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.

Signs and Symptoms in 1,043 Patients with Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a complex pain disorder that can emerge after limb trauma or a lesion in the peripheral nervous system. Typical features include continuing pain, sensory, vasomotor, sudomotor, motor, and trophic changes as well as edema. These signs provide the basis of CRPS diagnosis. A detailed description of the signs, symptoms, and medical history of CRPS could potentially facilitate an earlier and more accurate diagnosis. The aim of this study was to provide such a description, on the basis of epidemiological measures, clinical presentation, and a thorough description of pain sensations. Some signs (eg, differences of skin temperature >1°C), which have been thought to be crucial for diagnosis, were less common than assumed. We identified 11 distinct etiological triggers, which cover more than 99% of the study participants. We developed a weighted score on the basis of the most decisive data, which achieved a sensitivity of .869 and a specificity of .829, compared with .819 and .679 for the Budapest criteria. The weighted diagnostic criteria may help to better aid in distinguishing CRPS from other pain disorders.

PERSPECTIVE

This article provides a retrospective epidemiological analysis of 1,043 CRPS patients compared with 421 patients with other pain disorders. The findings could potentially facilitate a more reliable and earlier diagnosis of CRPS, a better differentiation from other pain disorders, and ultimately in a more targeted and effective therapy.

Operative Treatment of Intra-Articular Distal Radius Fractures With versus Without Arthroscopy: study protocol for a randomised controlled trial

Background

In the past several years, an increase in open reduction and internal fixation (ORIF) for intra-articular distal radius fractures has been observed. This technique leads to a quicker recovery of function compared to non-operative treatment. However, some patients continue to have a painful and stiff wrist postoperatively. Arthroscopically assisted removal of intra-articular fracture haematoma and debris may improve the functional outcomes following operative treatment of intra-articular distal radius fractures. The purpose of this randomised controlled trial is to determine the difference in functional outcome, assessed with the Patient-Rated Wrist Evaluation (PRWE) score, after ORIF with and without an additional wrist arthroscopy in adult patients with displaced complete articular distal radius fractures.

Methods

In this multicentre trial, adult patients with a displaced complete articular distal radius fracture are randomised between ORIF with an additional wrist arthroscopy to remove fracture haematoma and debris (intervention group) and conventional fluoroscopic-assisted ORIF (control group). The primary outcome is functional outcome assessed with the PRWE score after three months. Secondary outcomes are wrist function assessed with the Disability of the Arm, Shoulder and Hand (DASH) score, postoperative pain, range of motion, grip strength, complications and cost-effectiveness. Additionally, in the intervention group, the quality of reduction, associated ligamentous injuries and cartilage damage will be assessed. A total of 50 patients will be included in this study.

Discussion

Although ORIF of intra-articular distal radius fractures leads to a quicker resume of function compared to non-operative treatment, some patients continue to have a painful and stiff wrist postoperatively. We hypothesise that, due to the removal of fracture haematoma and debris by an additional arthroscopy, functional outcomes will be better compared to the non-arthroscopically treated group.

Trial registration

ClinicalTrials.gov, NCT02660515. Registered on 13 January 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2409-2) contains supplementary material, which is available to authorized users.

Transcranial magnetic stimulation studies in complex regional pain syndrome type I: A review

The sensory and motor cortical representation corresponding to the affected limb is altered in patients with complex regional pain syndrome (CRPS). Transcranial magnetic stimulation (TMS) represents a useful non-invasive approach for studying cortical physiology. If delivered repetitively, TMS can also modulate cortical excitability and induce long-lasting neuroplastic changes. In this review, we performed a systematic search of all studies using TMS to explore cortical excitability/plasticity and repetitive TMS (rTMS) for the treatment of CRPS. Literature searches were conducted using PubMed and EMBASE. We identified 8 articles matching the inclusion criteria. One hundred fourteen patients (76 females and 38 males) were included in these studies. Most of them have applied TMS in order to physiologically characterize CRPS type I. Changes in motor cortex excitability and brain mapping have been reported in CRPS-I patients. Sensory and motor hyperexcitability are in the most studies bilateral and likely involve corresponding regions within the central nervous system rather than the entire hemisphere. Conversely, sensorimotor integration and plasticity were found to be normal in CRPS-I. TMS examinations also revealed that the nature of motor dysfunction in CRPS-I patients differs from that observed in patients with functional movement disorders, limb immobilization, or idiopathic dystonia. TMS studies may thus lead to the implementation of correct rehabilitation strategies in CRPS-I patients. Two studies have begun to therapeutically use rTMS. This non-invasive brain stimulation technique could have therapeutic utility in CRPS, but further well-designed studies are needed to corroborate initial findings.

Utility of Radionuclide Bone Scintigraphy in Complex Regional Pain Syndrome

PURPOSE OF REVIEW

To describe the current understanding of the role of three-phase bone scintigraphy (TPBS) in the diagnosis and management of complex regional pain syndrome (CRPS), discuss its advantages and limitations, and present three examples of TPBS patterns typically seen in CRPS patients.

RECENT FINDINGS

CRPS is a debilitating disorder frequently presenting with pain to ordinarily non-painful stimuli, redness, swelling, following fractures, stroke, myocardial infarction, surgery, or even minor trauma, and its diagnosis, based on clinical criteria and supportive imaging findings, is difficult. Of the available adjunctive diagnostic imaging modalities, radionuclide bone scintigraphy using a TPBS protocol is the most sensitive and specific for detecting abnormalities commonly seen with this condition-classically, increased periarticular uptake on delayed phase of TPBS, with variable increased uptake on perfusion phases, depending on chronicity. Recent studies have (1) demonstrated a more heterogeneous correlation of TPBS findings with CRPS diagnosis using the current Budapest criteria than in studies using older criteria, (2) pointed to the utility of novel quantitative scintigraphic techniques, and (3) highlighted the value of the early perfusion phases of TPBS in predicting treatment response. TPBS remains a valuable imaging adjunct to clinical diagnosis of CRPS. In combination with a multi-modal analgesic approach, TPBS can be used to follow disease course and potentially treatment response, although prospective trials are needed to further delineate its role.

Development of a complex intervention for people with chronic pain after knee replacement: the STAR care pathway

BACKGROUND

Approximately 20% of people who have total knee replacement experience chronic pain afterwards, but there is little evidence about effective interventions for managing this type of pain. This article describes the systematic development and refinement of a complex intervention for people with chronic pain after knee replacement. The intervention is a care pathway involving an assessment clinic and onward referral, with telephone follow-up as required. In the design of this multistage study, we chose to focus on ensuring that the intervention was deliverable, implementable and acceptable.

METHODS

In line with the UK Medical Research Council's recommendations for comprehensive development of complex interventions, multiple phases of work were undertaken. Following on from initial development work to design the intervention, the draft intervention content was refined through consensus questionnaires with 22 health professionals and discussion at meetings with 18 healthcare professionals. Testing of intervention delivery and acceptability to patients was undertaken by two health professionals delivering the assessment clinic to ten patients. Views about future implementation within the context of a randomised trial were evaluated through a questionnaire based on the Normalisation Measure Development (NoMAD) instrument with ten health professional stakeholders.

RESULTS

Consensus work with health professionals ensured the components of the intervention were appropriate and informed a number of substantive changes to improve the intervention. Testing of intervention delivery identified a number of logistical issues that were then addressed in the development of a comprehensive intervention training manual. Engagement with stakeholders indicated that the intervention could be successfully implemented in a clinical setting for evaluation in a randomised trial.

CONCLUSIONS

This work has informed the development and refinement of a complex intervention for people with chronic pain after knee replacement. The next stage is to evaluate the clinical and cost-effectiveness of the STAR care pathway in a multicentre randomised trial.

Complex regional pain syndrome (CRPS)

Introduction: Complex regional pain syndrome (CRPS) is a relatively rare disorder, but one that is extremely serious for the affected patient. It usually occurs in the area distal to a primary limb injury. The clinical symptoms and the pain are out of all proportion to the inciting event and in approximately 10 % of CRPS patients, there is no triggering event at all. CRPS leads to long-term disability and high treatment and follow-up costs In about half of those affected.

Clinical symptoms: Two forms exist. In CRPS type 1, no nerve lesions are present, whereas in CRPS type 2, injury has occurred to a nerve or the main branch of a nerve. However, in terms of their clinical course, there is no difference between the two forms. Approximately 90 % of all cases involve CRPS type 1, formerly known as “Sudeck’s atrophy”. The cardinal symptom is pain. In addition, trophic disturbances, such as swelling, local skin discolouration or asymmetric skin temperatures, can also occur. Impaired mobility and function of the affected limb also occur frequently and are very difficult to treat.

Diagnosis: Initially, it can be difficult to distinguish between CRPS and a normal post-traumatic course. Subsequently, the severe symptoms are out of all proportion to the inciting event. The diagnosis of CRPS is based mainly on the clinical symptoms. The Budapest criteria help to confirm the diagnosis.

Therapy: Early and interdisciplinary rehabilitation is of crucial importance in CRPS treatment. Occupational therapy and physiotherapy are supplemented by good analgesic management and psychological support, if required. Analgesia should be based on the WHO pain ladder. Methadone is of proven efficacy in cases of severe hyperalgesia and gabapentin or pregabalin are used to treat refractory pain. Bisphosphonates have shown a good analgesic effect, particularly in patients with confirmed bone lesions. Chronic oedema and inflammation may require short-term steroid administration. A further clinical goal is the avoidance of sequelae, such as osteoporosis. Patients with suspected CRPS should be referred to a multidisciplinary treatment team, preferably one with considerable experience in treating this clinical presentation. One physician should coordinate the patient’s treatment. The earlier the treatment is started, the better the prognosis.

Identification of complex regional pain syndrome in the upper limb: Skin temperature asymmetry after cold pressor test

Background

Skin temperature asymmetry (SkTA) may assist in early identification of complex regional pain syndrome (CRPS), but previous work has been limited by methodological shortcomings including failure to account for the cutaneous nerve distribution where temperature is measured and reliance on laboratory equipment not clinically available. Pilot work suggested that a cold pressor test (CPT) provided a consistent thermoregulatory stress and might increase sensitivity/specificity of SkTA measurements generated reliably by handheld infrared (IR) thermometers.

Aims

This study investigated the sensitivity, specificity, and validity of SkTA in the upper limb to identify CRPS.

Methods

This study was part of a larger clinical trial (the SARA study: www.clinicaltrials.gov NCT02070367). Using IR thermometers, we evaluated SkTA over major peripheral nerve distributions in the hands before and after immersing a single foot in 5°C water for 30 s. Participant groups included healthy volunteers, CRPS, known nerve injury, and hand fracture.

Results

SkTA was measured in 65 persons, including 17 persons with CRPS (meeting Budapest criteria). Analysis of variance for n = 378 SkTA observations supported diagnosis, CPT, and nerve distribution as significant predictors (P < 0.001) explaining 94% of the variance. Post CPT, sensitivity for a >1.5°C SkTA improved to 82.4% from 58.8%, whereas specificity dropped from 56.3% to 43.8%.

Conclusion

This study adds further support for the accuracy of SkTA as a diagnostic indicator of CRPS. Further precision in estimates will be gained from larger studies, which should also seek to replicate our findings for SkTA in the lower limbs.

Current practice in the rehabilitation of complex regional pain syndrome: a survey of practitioners

INTRODUCTION

International clinical guidelines for Complex Regional Pain Syndrome recommend a wide range and variation of rehabilitation therapies as the core treatment. It is likely that most therapists employ a range of approaches when managing people with Complex Regional Pain Syndrome but a recent Cochrane review identified little evidence relating to the effectiveness of multi-modal rehabilitation. There is need for up to date trials of rehabilitation for Complex Regional Pain Syndrome, but in order to develop a clear model of best practice that can be rigorously evaluated we need to understand current practice.

METHOD

An electronic survey was disseminated internationally to clinicians involved in the rehabilitation of individuals with Complex Regional Pain Syndrome. The survey aimed to establish which criteria are used for diagnosis and which modalities clinicians use to treat Complex Regional Pain Syndrome and which they consider ineffective or harmful.

RESULTS

132 valid responses were received. A third of participants did not use any established criteria to diagnose Complex Regional Pain Syndrome. Current practice commonly included patient education, encouragement of self-management, and physical exercises. Cortically directed treatments such as graded motor imagery and psychological approaches were often incorporated into treatment whereas pain provocative therapies, splinting, contrast bathing, and cold and heat therapy were rarely used in the acute or chronic phase of Complex Regional Pain Syndrome.

CONCLUSION

A broad range of modalities are currently used in Complex Regional Pain Syndrome rehabilitation. Practice appears to be characterized by educational and exercise based interventions delivered in a pain-contingent manner which largely echoes recommendations in international clinical guidelines. Implications for Rehabilitation: Patients with Complex Regional Pain Syndrome suffer from a painful and disabling condition for which we still do not know the best treatment options. From our survey sample most clinicians use treatments recommended in the international guidelines. A large proportion of clinicians from our survey sample are not using internationally recognized diagnostic criteria and we therefore recommend that clinicians become familiar with these criteria and use them for all suspected Complex Regional Pain Syndrome cases.

Management of complex regional pain syndrome

Complex regional pain syndrome (CRPS) is a relatively rare, chronic, and debilitating condition that significantly impacts the patient's quality of life. There is an overall paucity of literature addressing the management of CRPS in immunocompromised patients. We define features of CRPS, outline its treatment options, and describe a course of CRPS management for a 35-year-old patient who had heart transplantation requiring immunosuppressive medications.

Primary bone lymphoma of the talus: a challenging diagnosis

PURPOSE

Diagnostic challenges are common in clinical practice and diagnostic or classification criteria for musculoskeletal conditions cannot overshadow clinical skills.

METHODS

We present the case of a young man who complained of prolonged articular pain and mild swelling of the right ankle in the absence of other remarkable data. Apparently fulfilling the Budapest diagnostic criteria for complex regional pain syndrome, the patient was treated accordingly, but the pain increased over time. Then the patient underwent an additional diagnostic workup including synovial and bone biopsies in 2 separate occasions with the second one demonstrating diffuse lymphoid infiltrate compatible with lymphoma.

RESULTS

The conclusive diagnosis of primary diffuse large B-cell lymphoma of the talus was made and adequate treatment initiated.

CONCLUSIONS

The diagnostic difficulties as well as the importance of a multidisciplinary approach for complex cases are highlighted in this report.

Complex regional pain syndrome-up-to-date

Complex regional pain syndrome (CRPS) was described for the first time in the 19th century by Silas Weir Mitchell. After the exclusion of other causes, CRPS is characterised by a typical clinical constellation of pain, sensory, autonomic, motor, or trophic symptoms which can no longer be explained by the initial trauma. These symptoms spread distally and are not limited to innervation territories. If CRPS is not improved in the acute phase and becomes chronic, the visible symptoms change throughout because of the changing pathophysiology; the pain, however, remains. The diagnosis is primarily clinical, although in complex cases further technical examination mainly for exclusion of alternative diagnoses is warranted. In the initial phase, the pathophysiology is dominated by a posttraumatic inflammatory reaction by the activation of the innate and adaptive immune system. In particular, without adequate treatment, central nociceptive sensitization, reorganisation, and implicit learning processes develop, whereas the inflammation moderates. The main symptoms then include movement disorders, alternating skin temperature, sensory loss, hyperalgesia, and body perception disturbances. Psychological factors such as posttraumatic stress or pain-related fear may impact the course and the treatability of CRPS. The treatment should be ideally adjusted to the pathophysiology. Pharmacological treatment maybe particularly effective in acute stages and includes steroids, bisphosphonates, and dimethylsulfoxide cream. Common anti-neuropathic pain drugs can be recommended empirically. Intravenous long-term ketamine administration has shown efficacy in randomised controlled trials, but its repeated application is demanding and has side effects. Important components of the treatment include physio- and occupational therapy including behavioural therapy (eg, graded exposure in vivo and graded motor imaging). If psychosocial comorbidities exist, patients should be appropriately treated and supported. Invasive methods should only be used in specialised centres and in carefully evaluated cases. Considering these fundamentals, CRPS often remains a chronic pain disorder but the devastating cases should become rare.

Alternatives to Opioids in the Pharmacologic Management of Chronic Pain Syndromes: A Narrative Review of Randomized, Controlled, and Blinded Clinical Trials

Chronic pain exerts a tremendous burden on individuals and societies. If one views chronic pain as a single disease entity, then it is the most common and costly medical condition. At present, medical professionals who treat patients in chronic pain are recommended to provide comprehensive and multidisciplinary treatments, which may include pharmacotherapy. Many providers use nonopioid medications to treat chronic pain; however, for some patients, opioid analgesics are the exclusive treatment of chronic pain. However, there is currently an epidemic of opioid use in the United States, and recent guidelines from the Centers for Disease Control (CDC) have recommended that the use of opioids for nonmalignant chronic pain be used only in certain circumstances. The goal of this review was to report the current body of evidence-based medicine gained from prospective, randomized-controlled, blinded studies on the use of nonopioid analgesics for the most common noncancer chronic pain conditions. A total of 9566 studies were obtained during literature searches, and 271 of these met inclusion for this review. Overall, while many nonopioid analgesics have been found to be effective in reducing pain for many chronic pain conditions, it is evident that the number of high-quality studies is lacking, and the effect sizes noted in many studies are not considered to be clinically significant despite statistical significance. More research is needed to determine effective and mechanism-based treatments for the chronic pain syndromes discussed in this review. Utilization of rigorous and homogeneous research methodology would likely allow for better consistency and reproducibility, which is of utmost importance in guiding evidence-based care.

Does Temperature Increase by Sympathetic Neurolysis Improve Pain in Complex Regional Pain Syndrome? A Retrospective Cohort Study

BACKGROUND

Lumbar sympathetic neurolysis (LSN) is a treatment option for complex regional pain syndrome (CRPS). We examined whether LSN-related temperature changes are associated with clinical outcome and investigated relationships between the outcome of LSN and clinical variables in patients with CRPS-I.

METHODS

We included 95 patients with CRPS-I affecting a single lower extremity, by the Budapest criteria, and who underwent LSN after successful lumbar sympathetic blocks, in this retrospective study. Fluoroscopy-guided LSN was conducted with 1.5 mL of 99% alcohol at L2 and L3 vertebral levels. Positive outcome was defined as a reduction of ≥50% on a numeric rating scale pain score at 6 months after LSN. The relationship between successful outcome and clinical variables was analyzed.

RESULTS

Positive LSN outcome occurred in 49.5% of patients, and it was suggested that Sympathetically maintained pain may accompany CRPS-I in 28% of patients. The overall temperature in the affected limb was increased after LSN, without contralateral limb temperature changes, but did not differ significantly between the positive and negative outcome groups (P = 0.590). Temperature after LSN in warm-type CRPS was reduced in the affected limb, without contralateral limb temperature changes. The absolute temperature change was significantly greater in cold-type than in warm-type CRPS (P = 0.026). In multivariate analysis, a short duration of pain and concurrent cold intolerance were significant factors predicting a positive outcome after LSN.

CONCLUSIONS

LSN may be effective in some patients with CRPS, irrespective of temperature changes and temperature asymmetry pattern. A short duration of pain and concurrent cold intolerance significantly predict successful LSN.

Risk Factors for Post-treatment Complex Regional Pain Syndrome (CRPS): An Analysis of 647 Cases of CRPS from the Danish Patient Compensation Association

OBJECTIVES

Complex regional pain syndrome is a challenging condition that includes a broad spectrum of sensory, autonomic, and motor features predominantly in extremities recovering from a trauma. Few large-scale studies have addressed occurrence of and factors associated with complex regional pain syndrome (CRPS) following orthopedic treatment. The present study aimed to identify factors associated with post-treatment development of CRPS.

METHODS

Using the Danish Patient Compensation Association's database, we identified 647 patients claiming post-treatment CRPS between 1992 and 2015. Age, gender, initial diagnosis, treatment, and amount of compensation were extracted. Multivariate logistic regressions were performed to identify variables associated with approval of the claim. For carpal tunnel syndrome (CTS) patients, we registered whether symptoms were bilateral or unilateral and if neurophysiology prior to treatment was pathologic.

RESULTS

The following ratios were found: women:men was 4:1, primary diagnosis to the upper limb:lower limb was 2.5:1, and surgical:nonsurgical treatment was 3:1. Mean age was 47.5 ± 13.7 years, and no intergender difference was detected. Antebrachial fracture (23%) and CTS (9%) were the most common primary conditions. Surgical treatment was associated with approval of the claim (odds ratio 3.5, 95% confidence interval 2.3 to 5.3; P < 0.001). Half of CTS patients had normal neurophysiology prior to surgery; among patients with unilateral symptoms, 71.4% had normal neurophysiology.

CONCLUSIONS

Female gender, surgical treatment, and treatment to the upper limb were risk factors. Elective surgery accounted for a large number of post-treatment CRPS patients. In CTS patients developing CRPS, normal neurophysiological examination findings were common, and it could be suspected that these patients were suffering from an pre-clinical stage of CRPS, not CTS.

Different patterns in mental rotation of facial expressions in complex regional pain syndrome patients

Although facial pain expressions are considered to be the most visible pain behaviors, it is known that the association between pain intensity and facial pain expression is weak for chronic pain. The authors hypothesized that the facial pain expressiveness was altered in chronic pain and investigated it with a mental rotation task using various facial expression, which seems to be associated with actual facial movements. As a task stimulus, 4 types of facial expression stimuli consisted of upper (tightening of eye and furrowed brows) and lower (raising upper lip) pain-specific facial expressions, and upper (eyeball deviation) and lower (tongue protrusion) facial movements not using facial muscles were used. Participants were asked to judge whether a stimulus presented at various rotation angles was left- or right-sided. The authors tested 40 patients with complex regional pain syndrome (CRPS) (12 women, age range 21-60) and 35 healthy controls (15 women, age range 26-64). In an analysis of reaction time (RT) using a linear mixed model, patients were slower to react to all types of stimuli (P = .001) and a significant interaction between group (patient or control) and type of facial expression was observed (P = .01). In the post hoc analysis only patients showed longer RTs to raising upper lip than other types of facial expressions. This reflects a deficit in mental rotation tasks especially for lower facial region pain expressions in CRPS, which may be related to the psychosocial aspects of pain. However, comprehensive intra- and interpersonal influences should be further investigated.

Biased visuospatial perception in complex regional pain syndrome

Complex regional pain syndrome (CRPS) is a chronic pain condition associating sensory, motor, trophic and autonomic symptoms in one limb. Cognitive difficulties have also been reported, affecting the patients’ ability to mentally represent, perceive and use their affected limb. However, the nature of these deficits is still a matter of debate. Recent studies suggest that cognitive deficits are limited to body-related information and body perception, while not extending to external space. Here we challenge that statement, by using temporal order judgment (TOJ) tasks with tactile (i.e. body) or visual (i.e. extra-body) stimuli in patients with upper-limb CRPS. TOJ tasks allow characterizing cognitive biases to the advantage of one of the two sides of space. While the tactile TOJ tasks did not show any significant results, significant cognitive biases were observed in the visual TOJ tasks, affecting mostly the perception of visual stimuli occurring in the immediate vicinity of the affected limb. Our results clearly demonstrate the presence of visuospatial deficits in CRPS, corroborating the cortical contribution to the CRPS pathophysiology, and supporting the utility of developing rehabilitation techniques modifying visuospatial abilities to treat chronic pain.

The Acquisition and Extinction of Fear of Painful Touch: A Novel Tactile Fear Conditioning Paradigm

Fear of touch, due to allodynia and spontaneous pain, is not well understood. Experimental methods to advance this topic are lacking, and therefore we propose a novel tactile conditioning paradigm. Seventy-six pain-free participants underwent acquisition in a predictable as well as an unpredictable pain context. In the predictable context, vibrotactile stimulation was paired with painful electrocutaneous stimulation (simulating allodynia). In the unpredictable context, vibrotactile stimulation was unpaired with pain (simulating spontaneous pain). During an extinction phase, a cue exposure and context exposure group continued in the predictable and unpredictable context, respectively, without pain. A control group received continued acquisition in both contexts. Self-reported fear and skin conductance responses, but not startle responses, showed fear of touch was acquired in the predictable context. Context-related startle responses showed contextual fear emerged in the unpredictable context, together with elevated self-reported fear and skin conductance responses evoked by the unpaired vibrotactile stimulations. Cue exposure reduced fear of touch, whereas context exposure reduced contextual fear. Thus, painful touch leads to increased fear, as does touch in the same context as unpredictable pain, and extinction protocols can reduce this fear. We conclude that tactile conditioning is valuable for investigating fear of touch and can advance our understanding of chronic pain.

PERSPECTIVES

The acquisition and extinction of fear of touch was investigated in a clinical analog study using a novel tactile fear conditioning paradigm. The results have implications for research on the development and treatment of chronic pain conditions characterized by allodynia and spontaneous pain fluctuations.

Iatrogenic Injuries of the Palmar Branch of the Median Nerve Following Volar Plate Fixation of the Distal Radius

Background: Our aims were to identify iatrogenous injuries to the palmar branch of the median nerve sustained during volar plate fixation of the distal radius, make the clinician aware of this relatively uncommon complication of distal radius fixation, to emphasise common threads in symptomatology and to propose an algorithm for evaluation and management.

Methods: Retrospectively interrogating our database over a 5 year period, the case records, neurophysiology records, operative records, therapy records were reviewed. The data was analysed with regard to the grade of surgeon performing the procedure, the site of injury, complexity of the fracture, delay to surgery, implant choice and outcome of the treatment. Variations in nerve anatomy were documented during revision surgery and common themes in symptomatology and clinical presentation were identified.

Results: Seven patients with an iatrogenic injury involving the palmar branch of the median nerve associated with volar plate fixation of the distal radius were assessed. The male: female ratio was 1:6 and the mean age of patients was 47.8 years (33-74 years). The initial operative fixation was undertaken by a consultant orthopaedic surgeon at a mean of 7.8 (1-17) days from injury. The mean time from fracture fixation surgery to referral to the peripheral nerve injury service was 8.9 (2-36) months. Six patients presented with pain on attempted wrist extension. Five patients had parasthesia, hyperaesthesia or dysaesthesia in the distribution of the PCBMN. Anaesthesia or hypoaesthesia was present in three patients. Two patients presented with symptoms of complex regional pain syndrome (CRPS) Type 2.

Conclusions: Revising relevant anatomy and possible variations as well as careful placements of retractors in the region of the median nerve could bring down these injuries. We propose an algorithm for their management.

Bodily Sensory Inputs and Anomalous Bodily Experiences in Complex Regional Pain Syndrome: Evaluation of the Potential Effects of Sound Feedback

Neuroscientific studies have shown that human's mental body representations are not fixed but are constantly updated through sensory feedback, including sound feedback. This suggests potential new therapeutic sensory approaches for patients experiencing body-perception disturbances (BPD). BPD can occur in association with chronic pain, for example in Complex Regional Pain Syndrome (CRPS). BPD often impacts on emotional, social, and motor functioning. Here we present the results from a proof-of-principle pilot study investigating the potential value of using sound feedback for altering BPD and its related emotional state and motor behavior in those with CRPS. We build on previous findings that real-time alteration of the sounds produced by walking can alter healthy people's perception of their own body size, while also resulting in more active gait patterns and a more positive emotional state. In the present study we quantified the emotional state, BPD, pain levels and gait of twelve people with CRPS Type 1, who were exposed to real-time alteration of their walking sounds. Results confirm previous reports of the complexity of the BPD linked to CRPS, as participants could be classified into four BPD subgroups according to how they mentally visualize their body. Further, results suggest that sound feedback may affect the perceived size of the CRPS affected limb and the pain experienced, but that the effects may differ according to the type of BPD. Sound feedback affected CRPS descriptors and other bodily feelings and emotions including feelings of emotional dominance, limb detachment, position awareness, attention and negative feelings toward the limb. Gait also varied with sound feedback, affecting the foot contact time with the ground in a way consistent with experienced changes in body weight. Although, findings from this small pilot study should be interpreted with caution, they suggest potential applications for regenerating BDP and its related bodily feelings in a clinical setting for patients with chronic pain and BPD.

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.

Neurologic Injuries in Noncontact Sports

Noncontact sports are associated with a variety of neurologic injuries. Concussion, vascular injury (arterial dissection), and spinal cord trauma may be less common in noncontact sports, but require special attention from the sports neurologist. Complex regional pain disorders, muscle injury from repetitive use, dystonia, heat exposure, and vascular disorders (patent foramen ovale), occur with similar frequency in noncontact and contact sports. Management of athletes with these conditions requires an understanding of the neurologic consequences of these disorders, the risk of injury with return to play, and consideration for the benefits of exercise in health restoration and disease prevention.

Painful swelling after a noxious event and the development of complex regional pain syndrome 1: A one-year prospective study

BACKGROUND

The timing of diagnosis of complex regional pain syndrome (CRPS) 1 remains a challenge due to the large heterogeneity of clinical presentations. We describe the distribution and differences in outcomes and clinical manifestations between time points and patient groups with and without CRPS 1 following an initiating event.

METHODS

Prospective cohort study with a consecutive registration of patients presenting with painful swelling of the affected extremity after an initiating event and follow-up visits after 3, 6 and 12 months.

RESULTS

Forty-two patients were enrolled (37 females, mean age 55.1 years). At baseline, 35 participants (83%, females n = 30) fulfilled the diagnostic criteria for CRPS 1. At 3 months, 19 out of the initial 35 CRPS 1 patients (54%) did not meet the diagnostic criteria anymore. Besides our inclusion criteria of a painful swelling, early manifestations indicating a CRPS 1 primarily include an impaired quality of life (SF-35, EQ5-D), more pain (NRS, MPQ) and restricted range of motion.

CONCLUSIONS

CRPS 1 develops within 8 weeks following a noxious event. Although many CRPS 1 patients reach partial remission within the first 3 months, signs and symptoms do not improve significantly at 1 year. In order to identify prognostic risk factors large prospective cohort studies are needed.

SIGNIFICANCE

This prospective cohort study follows patients with complaints most suspected for complex regional pain syndrome (CRPS) 1. CRPS 1 develops within 8 weeks following a noxious event. Although many CRPS 1 patients reach partial remission within the 3 months, symptoms do not improve significantly at 1 year.

Recommendations for a first Core Outcome Measurement set for complex regional PAin syndrome Clinical sTudies (COMPACT)

Complex regional pain syndrome (CRPS) is a persistent pain condition that remains incompletely understood and challenging to treat. Historically, a wide range of different outcome measures have been used to capture the multidimensional nature of CRPS. This has been a significant limiting factor in the advancement of our understanding of the mechanisms and management of CRPS. In 2013, an international consortium of patients, clinicians, researchers, and industry representatives was established, to develop and agree on a minimum core set of standardised outcome measures for use in future CRPS clinical research, including but not limited to clinical trials within adult populations. The development of a core measurement set was informed through workshops and supplementary work, using an iterative consensus process. "What is the clinical presentation and course of CRPS, and what factors influence it?" was agreed as the most pertinent research question that our standardised set of patient-reported outcome measures should be selected to answer. The domains encompassing the key concepts necessary to answer the research question were agreed as follows: pain, disease severity, participation and physical function, emotional and psychological function, self-efficacy, catastrophizing, and patient's global impression of change. The final core measurement set included the optimum generic or condition-specific patient-reported questionnaire outcome measures, which captured the essence of each domain, and 1 clinician-reported outcome measure to capture the degree of severity of CRPS. The next step is to test the feasibility and acceptability of collecting outcome measure data using the core measurement set in the CRPS population internationally.

Elevated Plasma Levels of sIL-2R in Complex Regional Pain Syndrome: A Pathogenic Role for T-Lymphocytes?

The immune system has long been thought to be involved in the pathophysiology of complex regional pain syndrome (CRPS). However, not much is known about the role of the immune system and specifically T-cells in the onset and maintenance of this disease. In this study, we aimed to evaluate T-cell activity in CRPS by comparing blood soluble interleukin-2 receptor (sIL-2R) levels between CRPS patients and healthy controls. CRPS patients had statistically significant elevated levels of sIL-2R as compared to healthy controls (median sIL-2R levels: 4151 pg/ml (Q3 − Q1 = 5731 pg/ml − 3546 pg/ml) versus 1907 pg/ml (Q3 − Q1: 2206 pg/ml − 1374 pg/ml), p < 0.001, resp.). Furthermore, sIL-2R level seems to be a good discriminator between CRPS patients and healthy controls with a high sensitivity (90%) and specificity (89.5%). Our finding indicates increased T-cell activity in patients with CRPS. This finding is of considerable relevance as it could point towards a T-cell-mediated inflammatory process in this disease. This could pave the way for new anti-inflammatory therapies in the treatment of CRPS. Furthermore, sIL-2R could be a promising new marker for determining inflammatory disease activity in CRPS.

Dorsal Column Stimulation vs. Dorsal Root Ganglion Stimulation for Complex Regional Pain Syndrome Confined to the Knee: Patients' Preference Following the Trial Period

BACKGROUND AND OBJECTIVES

Patients with complex regional pain syndrome (CRPS) confined to the knee are often therapy resistant. Neurostimulation is an accepted treatment for CRPS. Although results with dorsal column (DC) stimulation in patients with CRPS confined to the knee are often disappointing, the availability of dorsal root ganglion (DRG) stimulation may provide new opportunities for this complaint. Therefore, this study explores patients' preference for DC stimulation vs. DRG stimulation in treating chronic pain due to CRPS confined to the knee.

METHODS

A prospective, observational crossover cohort study was conducted comparing 2 methods of neurostimulation, in randomized order, in patients with CRPS confined to the knee. After receiving DC and DRG stimulation during a trial period of 16 days, patients were asked which of the 2 methods they preferred. Patients with a successful trial period with one or both stimulation methods received a fully implantable system.

RESULTS

Twelve patients were included. After finishing the trial period, 10 patients (83.3%) preferred DRG stimulation and 2 (16.7%) preferred DC stimulation (P = 0.04).

CONCLUSION

To our knowledge, this is the first study to compare these 2 neurostimulation methods in patients with CRPS confined to the knee. Results show that the probability of the preference for either neurostimulation treatment significantly deviates from chance in favor of DRG stimulation.

Persistent idiopathic facial pain

Background

Persistent idiopathic facial pain (PIFP) is a chronic disorder recurring daily for more than two hours per day over more than three months, in the absence of clinical neurological deficit. PIFP is the current terminology for Atypical Facial Pain and is characterized by daily or near daily pain that is initially confined but may subsequently spread. Pain cannot be attributed to any pathological process, although traumatic neuropathic mechanisms are suspected. When present intraorally, PIFP has been termed ‘Atypical Odontalgia’, and this entity is discussed in a separate article in this special issue. PIFP is often a difficult but important differential diagnosis among chronic facial pain syndromes.

Aim

To summarize current knowledge on diagnostic criteria, differential diagnosis, pathophysiology and management of PIFP.

Methods

We present a narrative review reporting current literature and personal experience. Additionally, we discuss and differentiate the common differential diagnoses associated with PIFP including traumatic trigeminal neuropathies, regional myofascial pain, atypical neurovascular pains and atypical trigeminal neuropathic pains.

Results and conclusion

The underlying pathophysiology in PIFP is still enigmatic, however neuropathic mechanisms may be relevant. PIFP needs interdisciplinary collaboration to rule out and manage secondary causes, psychiatric comorbidities and other facial pain syndromes, particularly trigeminal neuralgia. Burden of disease and psychiatric comorbidity screening is recommended at an early stage of disease, and should be addressed in the management plan. Future research is needed to establish clear diagnostic criteria and treatment strategies based on clinical findings and individual pathophysiology.

[Complex regional pain syndrome]

The term complex regional pain syndrome (CRPS) describes a variety of painful conditions, which typically occur distally on an extremity following an initiating event. Characteristically CRPS exceeds the expected clinical course in both magnitude and duration. Clinical manifestations of CRPS include sensory, vasomotor, sudomotor, motor and trophic disorders. The diagnosis of CRPS is purely clinical and based on the modified Budapest criteria. Essential differential diagnoses in the early phase include infections, neurological compression and inflammatory conditions. Although benign courses have been reported, many patients develop a chronic condition with persisting complaints even after 1 year. Therapy is based on a variety of pharmacological, interventional, physiotherapeutic, occupational and psychiatric treatment options.

Bisphosphonates for treatment of Complex Regional Pain Syndrome type 1: A systematic literature review and meta-analysis of randomized controlled trials versus placebo

OBJECTIVES

Complex Regional Pain Syndrome Type 1 is a severely disabling pain syndrome with no definite established treatment. We have performed a systematic literature review and meta-analysis of all randomized controlled trials to assess the benefit of bisphosphonates on pain and function in patients with Complex Regional Pain Syndrome Type 1.

METHODS

A systematic literature search was performed in the Medline, Embase and Cochrane databases. Two authors selected independently blinded randomized trials comparing bisphosphonates to placebo on short-term (J30 to J40) and medium term pain (M2-M3), safety and function in patients with CRPS 1. The methodological quality of the studies was analyzed. Data were aggregated using the method of the inverse of the variance.

RESULTS

258 articles were identified. Four trials of moderate to good quality comprising 181 patients (90 in the bisphosphonate group and 91 in the placebo group) were included in this meta-analysis. Short-term pain Visual Analog Scale was significantly lower in the bisphosphonate group versus the placebo group (SMD=-2.6, 95%CI [-1.8, -3.4], P<0.001), as well as the medium term Visual Analog Scale pain (SMD=-2.5, 95%CI [-1.4, -3.6], P<0.001). There were more adverse events in the bisphosphonate group (35.5%) than in the placebo group (16.4%) with a relative risk of 2.1 (95%CI [1.3, 3.5], P=0.004) and a number needed to harm of 4.6, (95%CI [2.4, 168.0]) but no serious side effects.

CONCLUSIONS

Our results suggest that bisphosphonates reduce pain in patients with Complex Regional Pain Syndrome type 1. Other studies are needed to determine their effectiveness.

Pain reduction due to novel sensory-motor training in Complex Regional Pain Syndrome I – A pilot study

Background and aims

Patients suffering from Complex Regional Pain Syndrome (CRPS) of the upper limb show a changed cortical representation of the affected hand. The lip area invades the former hand area contralateral to the affected hand. This change in cortical representation is correlated to the intensity of ongoing pain in patients with CRPS. Further studies revealed that restoration of the original representation coincides with a decrease of pain. Sensory-motor training protocols can increase and/or relocate cortical somatosensory and motor representation areas of the fingers, as shown, for example, in Braille reading individuals and professional violin players. Further, there is evidence that sensory-motor discrimination training has a beneficial effect on both the intensity of pain and the mislocalization of sensory-motor cortical areas in CRPS patients. Based on these propositions, we developed a novel sensory-motor self-training paradigm for CRPS patients to use in a home-based manner.

Methods

Ten CRPS patients performed the sensory-motor training for 2 weeks. The training consists of a braille-like haptic task with different training modes (bi-manual, speed and memory training). During the training, as well as 1 week before and after, patients were asked to fill out pain diaries. Furthermore, measures of impairment were acquired at baseline and post training.

Results

Patients showed significant pain reduction after the 2 week training period. The overall disability as well as the depression scores showed a trend to improve after the 2 week training. The reduction in pain was correlated with the total amount of training performed.

Conclusions

This is a first proof of principle study of a novel sensory-motor self-training protocol to reduce pain in CRPS patients. The more consistent the patients trained the larger the pain reduction. Sensory-motor training, which can be performed on a regular basis at home might provide a novel interventional strategy to improve symptoms of CRPS.

Implications

Although a larger study needs to be conducted to confirm our findings, including long-term follow-up, the results show, that a sensory-motor home-based training is a strategy worth exploring further for the reduction of pain as well as high frequency training for patients with CRPS.

Supervised physical therapy vs home exercise program for patients with distal radius fracture: A single-blind randomized clinical study

STUDY DESIGN

Randomized clinical study.

INTRODUCTION

Supervised physical therapy (PT) and home exercise programs (HEPs) are frequently used in the rehabilitation of patients with distal radius fracture (DRF). However, there is no consensus as to whether unsupervised HEP provides comparable benefits to those achieved by supervised PT.

PURPOSE OF THE STUDY

To compare the improvements in pain and functional status between a supervised PT program and unsupervised HEP in DRF patients older than 60 years.

METHODS

A total of 74 patients were randomized into 2 groups. One group received 12 sessions of supervised PT (n = 37), and the other group followed an exercise program at home (n = 37). Three evaluations were performed, before the initiation of treatment, at 6-week, and 6-month follow-up. The study conducted a statistical power analysis to detect an intergroup difference score of 15 points on the Patient-Rated Wrist Evaluation (PRWE). The t-test or Mann-Whitney test was used, and it was set with a significance level of .05.

RESULTS

The supervised PT group showed clinically significant differences in the total PRWE score at 6 weeks (17.67 points, P = .000) in the PRWE function score (15.2 points, P = .000) and in the PRWE pain score (5.6 points, P = .039). There was also a significant difference in the total PRWE score at 6-month follow-up (17.05 points, P = .000) in the PRWE function score (14.5 points, P = .000) and in the PRWE pain score (2.5 points, P = .35).

CONCLUSIONS

A supervised PT program is more effective for improving function in the short- and medium-term when compared with HEP in patients older than 60 years with DRF extraarticular without immediate complications.

LEVEL OF EVIDENCE

1b.

Usefulness of bone scintigraphy for the diagnosis of Complex Regional Pain Syndrome 1: A systematic review and Bayesian meta-analysis

BACKGROUND

Since 2007, the Budapest criteria are recommended for the diagnosis of Complex Regional Pain Syndrome (CRPS) 1. The usefulness of bone scintigraphy (BS, index test) for the diagnosis of CRPS 1 remains controversial. Imperfect reference tests (RT) result in underestimation of the diagnostic accuracy of BS. Further, biased results can occur when a dependency between the RT and BS exists. The objective was to assess the impact of different RTs, specifically the Budapest criteria, and the assumed imperfect nature of the RT on the diagnostic accuracy of BS. Further, we analyzed the association between baseline characteristics and positive BS in patients with CRPS 1.

METHODS

Systematic literature review and Bayesian meta-analysis to assess the test accuracy of BS with and without accounting for the imperfect nature of the RT. We examined correlations (Spearman correlation coefficients / Wilcoxon tests) between baseline characteristics and the proportion of positive BS in patients with CRPS 1.

RESULTS

The pooled sensitivity was 0.804 (95% credible interval (CI) 0.225-1.0, 21 studies) and specificity 0.853 (95%CI 0.278-1.00). Sensitivity and specificity of BS increased when accounting for the imperfect nature of the RT. However, in studies using Budapest criteria as reference, the sensitivity decreased (0.551; 95% CI 0.046-1) and the specificity increased (0.935; 95% CI 0.306-1). Shorter disease duration and a higher proportion of males were associated with a higher proportion of positive BS (27 studies, disease duration <52 weeks Wilcoxon test p = 0.047, female proportion Spearman correlation -0.63, p = 0.009).

CONCLUSION

Compared to the accepted Budapest diagnostic criteria BS cannot be used to rule-in the diagnosis of CRPS 1. In patients with negative BS CRPS 1 is less likely the underlying illness. Studies using older or no diagnostic criteria should not be used to evaluate the diagnostic accuracy of BS in CRPS 1.

Tibial nerve stimulation with a miniature, wireless stimulator in chronic peripheral neuropathic pain

Peripheral neuropathic pain (PNP) and complex regional pain syndrome (CRPS) can be effectively treated with peripheral nerve stimulation. In this clinical trial report, effectiveness of novel, miniature, wirelessly controlled microstimulator of tibial nerve in PNP and CRPS was evaluated. In this pilot study the average preoperative visual analog scale (VAS) score in six patients was 7.5, with 1, 3 and 6 months: 2.6 (p=0.03), 1.6 (p=0.03), and 1.3 (p=0.02), respectively. The mean average score in the six patients a week preceding the baseline visit was 7.96, preceding the 1, 3 and 6 month visits: 3.32 (p=0.043), 3.65 (p=0.045), and 2.49 (p=0.002), respectively. The average short-form McGill pain score before surgery was 23.8, and after 1, 3 and 6 months it was 11.0 (p=0.45), 6.3 (p=0.043), and 4.5 (p=0.01), respectively. Applied therapy caused a reduction of pain immediately after its application and clinical improvement was sustained on a similar level in all patients for six months. No complications of the treatment were observed. Intermittent tibial nerve stimulation by using a novel, miniature, wirelessly controlled device can be effective and feasible in PNP and CRPS. It is a safe, minimally invasive, and convenient neuromodulative method.

Complex regional pain syndrome: evidence for warm and cold subtypes in a large prospective clinical sample

Limited research suggests that there may be Warm complex regional pain syndrome (CRPS) and Cold CRPS subtypes, with inflammatory mechanisms contributing most strongly to the former. This study for the first time used an unbiased statistical pattern recognition technique to evaluate whether distinct Warm vs Cold CRPS subtypes can be discerned in the clinical population. An international, multisite study was conducted using standardized procedures to evaluate signs and symptoms in 152 patients with clinical CRPS at baseline, with 3-month follow-up evaluations in 112 of these patients. Two-step cluster analysis using automated cluster selection identified a 2-cluster solution as optimal. Results revealed a Warm CRPS patient cluster characterized by a warm, red, edematous, and sweaty extremity and a Cold CRPS patient cluster characterized by a cold, blue, and less edematous extremity. Median pain duration was significantly (P < 0.001) shorter in the Warm CRPS (4.7 months) than in the Cold CRPS subtype (20 months), with pain intensity comparable. A derived total inflammatory score was significantly (P < 0.001) elevated in the Warm CRPS group (compared with Cold CRPS) at baseline but diminished significantly (P < 0.001) over the follow-up period, whereas this score did not diminish in the Cold CRPS group (time × subtype interaction: P < 0.001). Results support the existence of a Warm CRPS subtype common in patients with acute (<6 months) CRPS and a relatively distinct Cold CRPS subtype most common in chronic CRPS. The pattern of clinical features suggests that inflammatory mechanisms contribute most prominently to the Warm CRPS subtype but that these mechanisms diminish substantially during the first year postinjury.

Complex regional pain syndrome: a recent update

Complex regional pain syndrome (CRPS) is a debilitating condition affecting the limbs that can be induced by surgery or trauma. This condition can complicate recovery and impair one’s functional and psychological well-being. The wide variety of terminology loosely used to describe CRPS in the past has led to misdiagnosis of this condition, resulting in poor evidence-base regarding the treatment modalities available and their impact. The aim of this review is to report on the recent progress in the understanding of the epidemiology, pathophysiology and treatment of CRPS and to discuss novel approaches in treating this condition.

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.

Pain Phenotypes and Associated Clinical Risk Factors Following Traumatic Amputation: Results from Veterans Integrated Pain Evaluation Research (VIPER)

OBJECTIVE

To define clinical phenotypes of postamputation pain and identify markers of risk for the development of chronic pain.

DESIGN

Cross-sectional study of military service members enrolled 3-18 months after traumatic amputation injury.

SETTING

Military Medical Center.

SUBJECTS

124 recent active duty military service members.

METHODS

Study subjects completed multiple pain and psychometric questionnaires to assess the qualities of phantom and residual limb pain. Medical records were reviewed to determine the presence/absence of a regional catheter near the time of injury. Subtypes of residual limb pain (somatic, neuroma, and complex regional pain syndrome) were additionally analyzed and associated with clinical risk factors.

RESULTS

A majority of enrolled patients (64.5%) reported clinically significant pain (pain score ≥ 3 averaged over previous week). 61% experienced residual limb pain and 58% experienced phantom pain. When analysis of pain subtypes was performed in those with residual limb pain, we found evidence of a sensitized neuroma in 48.7%, somatic pain in 40.8%, and complex regional pain syndrome in 19.7% of individuals. The presence of clinically significant neuropathic residual limb pain was associated with symptoms of PTSD and depression. Neuropathic pain of any severity was associated with symptoms of all four assessed clinical risk factors: depression, PTSD, catastrophizing, and the absence of regional analgesia catheter.

CONCLUSIONS

Most military service members in this cohort suffered both phantom and residual limb pain following amputation. Neuroma was a common cause of neuropathic pain in this group. Associated risk factors for significant neuropathic pain included PTSD and depression. PTSD, depression, catastrophizing, and the absence of a regional analgesia catheter were associated with neuropathic pain of any severity.

[Complex regional pain syndrome: A review]

BACKGROUND

Complex regional pain syndrome is characterized by spontaneous or induced pain disproportionate in relation to the initial event and is accompanied by a variety of regional and motor disturbances, leading to a variety of clinical presentations. It is often associated with surgery and minor trauma.

PATHOPHYSIOLOGY

Three mechanisms are postulated: changes secondary to post traumatic inflammation, peripheral vasomotor dysfunction and structural and functional changes of the central nervous system as a result of maladaptation.

DIAGNOSIS

made based on the criteria of Budapest. The patient must have one symptom and sign of each criterion at diagnosis: Continuing pain, disproportionate to any inciting event. A sensory, vasomotor, oedema and motor/trophic change sign and symptoms that are not explained by another diagnosis or cause.

TREATMENT

Multimodal treatment is suggested. There is no gold standard. In early stage NSAIDs or steroids can be used. Drugs used for neuropathic pain treatment have been suggested, but there is not enough evidence for any of these. There is low evidence that bisphosphonates, calcitonin, ketamine and mirror therapy are effective compared to placebo. Interventional treatment should be stepped from epidural block, neurostimulation, intrathecal pump to experimental therapies in case of intractable pain.

DISCUSSION

Although complex regional pain syndrome has been a recognized entity for over 100 years, no clear evidence exists for first-line treatments; however, new technologies that are applicable in complex regional pain syndrome treatment have been developed.

Spontaneous recurrent episodes of wrist pain in a 16-year-old girl: a case of complex regional pain syndrome

CRPS in children may imitate rheumatologic diseases, but should be considered if typical signs are present. Diagnosis can be supported by three-phase bone scintigraphy.

Introduction: Complex regional pain syndromes (CRPS) are disabling pain syndromes that can develop after minor tissue injury or trauma and are characterized by sensory, motor, and autonomic abnormalities distributed in a glove-like or stocking-like manner. Complex regional pain syndrome is well known in adults, but is relatively rare in children. Most of the reported cases of CRPS in children are clinical diagnoses that are not supported by examinations such as three-phase bone scintigraphy. Furthermore, different centres often use different diagnostic criteria for CRPS, which sometimes questions the diagnosis of CRPS.

Objective/Methods: Although, recurrences and in particular relapses of CRPS have been observed, a periodically, nearly self-limiting course of disease without any residues in pain-free episodes and without any new obvious injury in CRPS is rather unusual. We present the case of a 16-year-old girl who reported recurrent spontaneous pain which lasted for 2 to 3 weeks and occurred approximately 2 times a year after the patient had experienced a mild trauma 3 years ago.

Results: The pain was accompanied by swelling, temperature asymmetry, and decreased range of motion of the right hand without any complains in pain-free episodes. Recurrent symptoms occurred without any obvious trauma. Diagnosis of CRPS was made from clinical findings including quantitative sensory testing, increased periarticular radioisotope uptake in the delayed phase of three-phase bone scintigraphy and examination during anaesthesia. Multimodal inpatient pain treatment resolved her symptoms substantially.

Conclusion: Complex regional pain syndrome in children may imitate rheumatologic diseases, and the course is different from adults despite similar clinical findings.

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 risk of pain syndrome affecting a previously non-painful limb following trauma or surgery in patients with a history of complex regional pain syndrome

BACKGROUND AND PURPOSE

Complex regional pain syndrome (CRPS) is a challenging complication after surgery or trauma. This study sought to determine the incidence of CRPS after a second inciting event in a previously unaffected extremity in patients with a history of an ongoing CRPS diagnosis in another extremity.

METHODS

A retrospective review identified patients with CRPS seen in clinic over a 20-month period. The incidence of CRPS after subsequent surgery or injury in a previous unaffected extremity was determined and compared to an average incidence reported in the literature.

RESULTS

Ninety-three patients had a diagnosis of primary CRPS. Nineteen (20.4%) developed CRPS in one or more additional extremity compared to the incidence of 23.4 per 100,000 (0.0234%) in the literature (odds ratio 1069.6, p<0.0001, 95% CI 562.0-2035.7). Twenty patients had a documented secondary injury or surgery in a second extremity. Fifteen (75%) developed secondary CRPS compared to a CRPS incidence rate of 6.4% following distal radius fracture, as determined by literature review (odds ratio 11.7, p<0.001, 95% CI 5.9-23.2).

CONCLUSIONS

These result suggest that patients with a history of CRPS are more likely to develop secondary CRPS compared to the rates reported in the literature among the general population.

IMPLICATIONS

Patients with a history of CRPS should be counselled that they may be at risk for developing secondary CRPS if they undergo surgery or sustain trauma to another extremity.