Epidural Infusion of Opiates and Local Anesthetics for Complex Regional Pain Syndrome

Abstract: Complex Regional Pain Syndrome Type‐I (CRPS‐I) is a neuropathic pain syndrome resulting from complex pain mechanisms that involve several levels and components of the nervous system. CRPS‐I consists of multiple signs, including autonomic dysfunction, in the form of edema, vasomotor changes, motor dysfunctions, muscle spasms, tremors and dystonia, as well as burning pain, hypersensitivity and allodynia that could present in any combination. The treatment is progressive physical therapy rehabilitation program. Multiple analgesic modalities have been used to facilitate the rehabilitation program with varying rates of success. The most successful treatment is a multi‐disciplinary comprehensive approach, where initial pain control allows for physical and psychological interventions that are believed to be the basis for successful treatment. ¹ The pain in CRPS‐I may be mediated through the sympathetic nervous system, sympathetic maintained pain (SMP) or sympathetic independent pain (SIP) ² .     

The passive transfer of immunoglobulin G serum antibodies from patients with longstanding Complex Regional Pain Syndrome

Background: The aetiology of Complex Regional Pain Syndrome (CRPS) is unknown. Recent evidence suggests that there may be autoantibodies directed against peripheral nerves, but it is unclear whether such autoantibodies are merely biomarkers or whether they cause or contribute to the underlying pathology. The transfer of disease after injection of a patient's serum or IgG fraction into mice (‘passive transfer’) is the classic way to demonstrate a functional role of autoantibodies. Aims: Based on previous preliminary results, we wished to investigate whether the transfer of IgG antibodies affected mouse behaviour or produced signs of CRPS. Methods: We injected purified serum‐IgG from 12 patients and 12 controls into groups of 6–10 mice (～17 mg/mouse intraperitoneally) on 2 consecutive days and looked for any evidence for altered behaviour or signs of CRPS. The observer, blinded as to test or control group, measured behaviour in the open field, stimulus‐evoked pain and motor coordination, and inspected limbs for autonomic CRPS signs. Results: Stimulus‐evoked pain and autonomic signs were not detected, but CRPS‐IgG induced significant depression of rearing behaviour (17.9 rears/3 min (n =84) vs. 22.1 rears/3 min (n =83), p =0.0004), confirming previous observations in a single case study. Moreover, motor impairment, one of the four cardinal signs of CRPS, was evident in the three CRPS‐IgG injected groups tested with a sensitive rota‐rod protocol (p <0.0001 vs. control‐IgG injected groups). Conclusions: These results lend support to a pathophysiological role for IgG autoantibodies in CRPS.     

Enhanced pain and autonomic responses to ambiguous visual stimuli in chronic Complex Regional Pain Syndrome (CRPS) type I

Cortical reorganisation of sensory, motor and autonomic systems can lead to dysfunctional central integrative control. This may contribute to signs and symptoms of Complex Regional Pain Syndrome (CRPS), including pain. It has been hypothesised that central neuroplastic changes may cause afferent sensory feedback conflicts and produce pain. We investigated autonomic responses produced by ambiguous visual stimuli (AVS) in CRPS, and their relationship to pain. Thirty CRPS patients with upper limb involvement and 30 age and sex matched healthy controls had sympathetic autonomic function assessed using laser Doppler flowmetry of the finger pulp at baseline and while viewing a control figure or AVS. Compared to controls, there were diminished vasoconstrictor responses and a significant difference in the ratio of response between affected and unaffected limbs (symmetry ratio) to a deep breath and viewing AVS. While viewing visual stimuli, 33.5% of patients had asymmetric vasomotor responses and all healthy controls had a homologous symmetric pattern of response. Nineteen (61%) CRPS patients had enhanced pain within seconds of viewing the AVS. All the asymmetric vasomotor responses were in this group, and were not predictable from baseline autonomic function. Ten patients had accompanying dystonic reactions in their affected limb: 50% were in the asymmetric sub‐group. In conclusion, there is a group of CRPS patients that demonstrate abnormal pain networks interacting with central somatomotor and autonomic integrational pathways.     

A Management of Early CRPS I Caused by Ankle Sprain: A Case Report

Abstract:   We present a case of a 13-year-old boy who developed signs and symptoms of neuropathic pain/early Complex Regional Pain Syndrome (CRPS) Type I, formerly known as Reflex Sympathetic Dystrophy (RSD), after spraining his ankle while wrestling. Aggressive pain control, using medications and sympatholytic blocks, with physical therapy and rehabilitation, led to the resolution of his painful condition. This prevented the disease from possibly progressing to a full-blown case of CRPS I (RSD) that is very challenging to treat.     

Complex regional pain syndromes in children and adolescents: regional and systemic signs and symptoms and hemodynamic response to tilt table testing

OBJECTIVE: Complex regional pain syndromes (CRPS) involve neuropathic limb pain and localized circulatory abnormalities. The authors hypothesized that (1) pediatric CRPS patients exhibit systemic autonomic symptoms and orthostatic and/or cardiac sympatho-vagal dysregulation and (2) their orthostatic regulation differs from healthy controls and pediatric patients with postural orthostatic tachycardia syndrome (POTS). METHODS: CRPS children and adolescents (n=20) underwent a 6-week trial of physical therapy and cognitive-behavioral treatment. Measures included pain and function scores, regional and systemic autonomic symptom profiles, heart rate and blood pressure with tilt, heart rate variability indices, and baroreflex gain. Systemic autonomic symptoms were recorded in 55 healthy pediatric controls. Tilt responses in CRPS patients were compared with those of 21 POTS patients and 39 healthy controls. RESULTS: CRPS patients' regional autonomic symptoms, pain, and limb function improved over 6 weeks (P<0.01). At baseline CRPS patients reported more systemic autonomic symptoms than controls (P<0.05). Tilt table test showed orthostatic stability, but the mean heart rate increase with tilt was greater in CRPS patients than controls (P<0.001). POTS patients showed significant increases with tilt in mean heart rate and diastolic and systolic blood pressures compared with controls (P<0.001). There were significant increases in the mean systolic and diastolic blood pressures in POTS compared with CRPS patients but no difference in the mean heart rate between groups. DISCUSSION: CRPS patients reported multiple regional and systemic autonomic symptoms that improved during the study course, and they experienced minimal and transient tilt table-induced hemodynamic changes compared with POTS patients but relatively similar to controls.     

Nicotine and caffeine intake in complex regional pain syndrome

{\it Objective:} Nicotine and caffeine are vasoconstrictors. Complex regional pain syndrome (CRPS) is defined to involve disproportionate pain and autonomic dysfunction [1]. The objectives of this study were to identify the prevalence of smoking and caffeine intake in CRPS, to explore the relationship of pain intensity with smoking and caffeine consumption, and to explore the relationship of pain intensity, anxiety and disability among CRPS patients who smoke, use caffeine, or both. {\it Design:} One hundred eleven patients, with CRPS type I or II, from two academic rehabilitation pain clinics were reviewed. Data were collected retrospectively by reviewing CRPS patients' self-reported pain level using visual analogue scales (VAS), Beck Depression Inventory (BDI), Pain Disability Index (PDI), and Pain Anxiety Symptoms Scale (PASS). Status of daily smoking and caffeine consumption were also recorded. {\it Results:} Smoking prevalence among CRPS was significant higher than the national average (p < 0.001). There were no significant relationships between the perceived pain level and either daily smoking, daily caffeine intake, or both (p > 0.430). In patients with CRPS I higher PASS scores were positively associated with dichotomous use of smoking and caffeine (p < 0.05). The PASS scores among patients with CRPS~II were not available for analysis. {\it Conclusions:} The smoking prevalence was higher than the national average among patients with CRPS I and II. Among patients with CRPS~I smoking and caffeine consumption were greater in those who reported more pain-related anxiety, but did not influence pain intensity. The clinical implications of these findings will be discussed.     

Complex regional pain syndrome type I treated with topical capsaicin: a case report. (Erasmus University Medical Center, Rotterdam, The Netherlands) Arch Phys Med Rehabil. 2001;82:851–852.

This report described the case of a multitrauma patient who underwent an amputation of the left arm and had a complicated left crural fracture with a delayed union. He was treated in an inpatient setting for preprosthetic training for a myoelectric prosthesis and to regain walking abilities. After consolidation of the crural fracture, complex regional pain syndrome type I (CRPS I) developed in the left foreleg, which hindered mobilization. Topical capsaicin 0.075% was prescribed and a stress-loading mobilization schema was instituted. No other treatment modalities directed at CRPS I were added. After 6 weeks, no signs or symptoms of CRPS I were present and capsaicin was discontinued. Capsaicin is a well-accepted and documented treatment modality in neuropathic pain states such as postherpetic neuralgia. However, it has rarely been described in CRPS I. Capsaicin is discussed within the framework of recent insights in the neurobiology of nociception, and it is concluded that it may provide a theory-driven treatment for CRPS I, especially in the acute stage, which facilitates physical therapy and prevents peripheral and spinal sensitization.     

Complex regional pain syndrome type I treated with topical capsaicin: a case report

This report describes the case of a multitrauma patient who underwent an amputation of the left arm and had a complicated left crural fracture with a delayed union. He was treated in an inpatient setting for preprosthetic training for a myoelectric prosthesis and to regain walking abilities. After consolidation of the crural fracture, complex regional pain syndrome type I (CRPS I) developed in the left foreleg, which hindered mobilization. Topical capsaicin .075% was prescribed and a stress-loading mobilization schema was instituted. No other treatment modalities directed at CRPS I were added. After 6 weeks, no signs or symptoms of CRPS I were present and capsaicin was discontinued. Capsaicin is a well-accepted and documented treatment modality in neuropathic pain states such as postherpetic neuralgia. However, it has rarely been described in CRPS I. Capsaicin is discussed within the framework of recent insights in the neurobiology of nociception, and it is concluded that it may provide a theory-driven treatment for CRPS I, especially in the acute stage, that facilitates physical therapy and prevents peripheral and spinal sensitization.     

Complex regional pain syndrome type I: incidence and prevalence in Olmsted county,a population-based study

The objective of this study is to undertake a population based study on the incidence, prevalence, natural history, and response to treatment of complex regional pain syndrome (CRPS). All Mayo Clinic and Olmsted Medical Group medical records with codes for reflex sympathetic dystrophy (RSD), CRPS, and compatible diagnoses in the period 1989-1999 were reviewed as part of the Rochester Epidemiology Project. We used IASP criteria for CRPS. The study population was in the Olmsted County, Minnesota (1990 population, 106,470). The main outcome measures were CRPS I incidence, prevalence, and outcome. Seventy-four cases of CRPS I were identified, resulting in an incidence rate of 5.46 per 100,000 person years at risk, and a period prevalence of 20.57 per 100,000. Female:male ratio was 4:1, with a median age of 46 years at onset. Upper limb was affected twice as commonly as lower limb. All cases reported an antecedent event and fracture was the most common trigger (46%). Excellent concordance was found between symptoms and signs and vasomotor symptoms were the most commonly present. Three phase bone scan and autonomic testing diagnosed the condition in >80% of cases. Seventy-four percent of patients underwent resolution, often spontaneously. CRPS I is of low prevalence, more commonly affects women than men, the upper more than the lower extremity, and three out of four cases undergo resolution. These results suggest that invasive treatment of CRPS may not be warranted in the majority of cases.     

Signs and symptoms in complex regional pain syndrome type I/reflex sympathetic dystrophy: judgment of the physician versus objective measurement.

OBJECTIVE: To assess the relation between the subjectively assessed and objectively measured diagnostic signs and symptoms in complex regional pain syndrome type I (CRPS I) and to quantify their severity. DESIGN: Diagnostic signs and symptoms were recorded in patients suffering from CRPS I of one upper extremity for less than 1 year. Independent assessors measured (a) pain by using four visual analog scales (VAS) and the McGill Questionnaire list of adjectives (MPQ), (b) edema with a hand volumeter, (c) skin temperature with an infrared thermometer, and (d) active range of motion (AROM) with goniometers. SETTING: Two university hospitals. PATIENTS: Ninety-five women and 40 men with CRPS I of one upper extremity. RESULTS: Four signs and symptoms were diagnosed in 50 patients, and five in the remaining 85 patients. The mean score for present pain intensity was 31.5 mm and that for pain resulting from exertion of the affected extremity was 71.9 mm. A median of 11.5 words was chosen from the MPQ, with the highest number from its evaluative part. The difference in volume between both hands was 30.4 ml. The mean difference in temperature between the two hands was 0.78 degrees C dorsally and 0.66 degrees C palmarly. The largest decrease in mobility was seen in the wrist and fingers; the thumb was relatively less affected and the little finger relatively more affected than the other fingers. CONCLUSIONS: Bedside evaluation of CRPS I with Veldman's criteria was in good accord with psychometric or laboratory testing of these criteria.     

Pharmacologic treatment of complex regional pain syndrome I: a conceptual framework

Pain may be a leading symptom in complex regional pain syndrome type I (CRPS I) and may hinder functional recovery. In this case, a pharmacotherapeutic approach to pain should be part of the individually tailored interdisciplinary treatment regimen. However, operational criteria for determining which patient may profit from what therapeutic intervention are lacking. This article discusses a conceptual framework in which the rapid progress made in basic pain research may contribute to the clinical management of pain in CRPS I. First, recent insights in the pathophysiologic mechanisms underlying CRPS I are reviewed. CRPS I is considered a neuropathic pain syndrome with a mixed and time-dependent profile of a regional inflammation, sensitization of primary somatosensory afferents (peripheral sensitization), and sensitization of spinal neurons (central sensitization). The dominant mechanisms may vary across individual patients with different time profiles. Second, a model was constructed in which signs and symptoms in an individual patient are related to these mechanisms. Finally, relating the clinical picture to the underlying pathophysiology may help determine the pharmacotherapeutic approach for an individual patient. Pharmacologic options are discussed in this context. The presented framework does not aim to provide an evidence-based treatment algorithm, ready to be used in daily clinical practice; rather it offers a crude, first step toward a mechanism-based pharmacotherapy in CRPS I, in an effort to shift from a mainly empirical treatment paradigm toward theory-driven treatment procedures.     

Pathogenesis of complex regional pain syndrome (CRPS)

Neuropathic pain results from injury to neural structures within the peripheral or central nervous systems. Such injury promotes spontaneous and ectopic firing of nerves as well as reorganization of the nervous system. Neuropathic pain persists chronically. Patients who suffer from neuropathic pain exhibit persistent or paroxysmal pain without apparent immediate cause or pain hypersensitivity after tissue damage. This hypersensitivity is manifest as hyperalgesia and allodynia. Complex regional pain syndrome, CRPS is a category of neuropathic pain and is further divided into type I(reflex sympathetic dystrophy: RSD) and type II(causalgia). CRPS is characterized by localized autonomic dysregulation in the affected area with vasomotor and/or sudomotor changes, edema, colour difference, sweating abnormality, and atrophy.     

Axillary brachial plexus block with patient controlled analgesia for complex regional pain syndrome type I: a case report. (National Cheng Kung University, Tainan, Taiwan) Reg Anesth Pain Med 2001;26:68–71.

A 32-year-old man who suffered from complex regional pain syndrome type I (CRPS I) of the right upper limb after surgical release of carpal tunnel syndrome of the right hand is the subject of this case report. Symptoms and signs over the right hand were alleviated under rehabilitation and conventional pharmacological management, but severe painful swelling of the right wrist persisted. Axillary brachial plexus block (BPB) with patient controlled analgesia (PCA) was performed on the 32^nd postoperative day, which soon resulted in significant reduction of pain with gradual improvement of function of the right wrist. Conclude that axillary BPB with PCA may provide patients with CRPS I of the upper limb a feasible and effective treatment.     

A case of pain,motor impairment,and swelling of the arm after acute herpes zoster infection

Complex regional pain syndrome (CRPS) and postherpetic neuralgia (PHN) represent neuropathic pain syndromes that may appear with similar clinical signs and symptoms. Medical history and clinical distribution of symptoms and signs (PHN typically at the thorax; CRPS typically at the limbs) is obvious in most cases, helping to discriminate between both disorders. Here, we present a patient suffering from CRPS II following PHN of one upper extremity. This case demonstrates that both etiology and part of the body affected by a neuropathy influence the pain phenotype.     

Physical Therapy (92)

J eanine Yip Menck, Susan Mais Requejo, Kornelia Kulig: Thoracic spine dysfunction in upper extremity complex regional pain syndrome type 1. (University of Southern California, Los Angeles, CA) J Orthop Sports Phys Ther 2000;30:401–409. The objective of this case study was to demonstrate the importance of assessment and treatment of the thoracic spine in the management of a patient with signs and symptoms of upper extremity complex regional pain syndrome type I. The patient was a 38‐year‐old woman who suffered a traumatic injury to her left hand. Five months after the injury, she presented with severe pain, immobility of the left arm, and associated dystrophic changes. She was unable to work and needed help in some activities of daily living. The patient was treated for 3 months in 36 visits. Initial treatment consisted of cutaneous desensitization, edema management, and gentle therapeutic exercises. However, further examination indicated hypomobility and hypersensitivity of the upper thoracic spine. Joint manipulation of the T3 and T4 segments was implemented. The patient's status was monitored. Immediately after the vertebral manipulation, there was significant increase in the left hand's skin temperature and a decrease in hyperhydrosis as measured by palpation. Shoulder range of motion increased from 135º to 175° and the patient reported reduced pain. The decrease in the patient's dystrophic and allodynic symptoms permitted further progress in functional reeducation. The patient was discharged with full return to independence and initiation of a vocational training program. Conclude that the assessment and treatment of the thoracic spine should be considered in patients with upper extremity complex regional pain syndrome type I. Comment by Karen Crawford, RPT. This is a study demonstrating the importance of assessment of the thoracic spine to manage patients with signs and symptoms of upper extremity complex regional pain syndrome type I (CRPS‐I). The patient was a 38‐year‐old female with traumatic injury to the left hand. The purpose of this study is to determine the relation between distal symptoms of CRPS‐I and the thoracic spine and to describe the use of thoracic spine manipulation in the management of patients with CRPS‐I in the upper extremity. CRPS‐I in the upper extremity often exhibits postural deviations associated with protective positioning of the arm. It emanates as trunk motion during upper activities and may present with decreased thoracic intervertebral mobility. This study believes that the evaluation and treatment in areas proximal to a patient's symptoms in CRPS‐I may be necessary. Hypomobility secondary to abnormal posturing and anatomical proximity of the sympathetic ganglions to the thoracic spine may contribute to the link between upper quadrant CRPS‐I and thoracic joint dysfunction. In the study, a 38‐year‐old, left‐hand dominant, female who sustained trauma to her left wrist and hand while at work was seen in physical therapy for a total of 36 visits. Initial treatment consisted of desensitization, edema management, and general therapeutic exercises. Further examination indicated hypomobility and hypersensitivity of the upper thoracic spine. At that time, joint manipulation of T3 and T4 segments was implemented. The patient's status was monitored and range of motion, strength, temperature, and skin moisture were measured. The patient reported minimal changes in her status, and 1 month into treatments, she hit her left hand on a door and consequently discontinued therapy because of increased pain. Five months after the initial injury, patient was reevaluated. She then received physical therapy 3 times per week for 12 weeks and was discharged with significant improved functional status. At the initial examination, the diagnosis of CRPS‐I was based on the IASP Committee on Taxonomy. The initial treatment objective was pain management and edema control. The long‐term goal was return to a functional status. Initial treatment consisted of gentle active and passive wrist and finger range of motion and tubagrip for edema management. A home program desensitization was implemented. The patient's active participation in therapy was limited secondary to her willingness to move her left arm. Treatment 2 included evaluation and manipulation of the upper thoracic spine. Her clinician used her manipulating hand as a fulcrum by placing it under the supine patient at the level of thoracic joint dysfunction. A thrust was delivered through the patient's folded arms as she exhaled and there as an audible click. There was an immediate normalization of skin temperature, color, as well as significantly decreased allodynic response to light touch along the left arm and the left upper thoracic vertebral column. Segmental thoracic mobility was immediately improved and there was immediate increase in shoulder flexion after this treatment. This reduction of signs and symptoms of CRPS‐I made it possible to proceed with functional rehabilitation. Manipulation of the thoracic spine may have resulted in improvements in distal upper extremity pain, skin color, and temperature in a patient with CRPS‐I. One explanation is that disuse of the arm and abnormal posturing may contribute to thoracic hypomobility. The anatomic proximity of the sympathetic chain to the dysfunctional thoracic joints may predispose the ganglions to mechanical pressure. Therefore, it is concluded that the evaluation and treatment of areas proximal to the patient's symptoms are necessary. It is difficult to identify the mechanism responsible for changing distal symptoms after thoracic manipulation. The immediate increase in shoulder flexion after manipulation is likely due to mechanical change in the tissue. In conclusion, this study describes a link between the thoracic spine and distal symptoms in patients with CRPS‐I. Thoracic joint manipulation appeared to improve spinal mobility, and also appeared to relieve distal and autonomic symptoms. These improvements allowed for functional rehabilitation of the effected arm. Therefore, it is the opinion of the study that the mobility of the thoracic spine should be evaluated for patients with autonomic dysfunction diagnosed with CRPS‐I. The research also indicates a need for further research to define the relationship between neurogenic symptoms and musculoskeletal pathology.     

Cross-diagnostic validity of the SF-36 physical functioning scale in patients with stroke, multiple sclerosis and amyotrophic lateral sclerosis: a study using Rasch analysis.

OBJECTIVE: The aim of this study was to investigate unidimensionality and differential item functioning of the SF-36 physical functioning scale (PF10) in patients with various neurological disorders. Patients: Patients post-stroke (n = 198), with multiple sclerosis (n = 151) and amyotrophic lateral sclerosis (n = 193) participated. METHODS: Unidimensionality of the PF10 within the patient groups was investigated by performing a separate Rasch analysis for each group. Differential item functioning was investigated in a pooled Rasch analysis of the 3 groups. RESULTS: Within each group, all items fitted the Rasch model, except the "bathing/dressing" item in the amyotrophic lateral sclerosis group. The pooled analysis showed inadequate fit to the Rasch model for one item ("walking several hundred metres"). Of the other 9 fitting items, 5 showed differential item functioning for stroke vs multiple sclerosis and amyotrophic lateral sclerosis, while no differential item functioning was found between multiple sclerosis and amyotrophic lateral sclerosis. CONCLUSION: All items of the PF10, except one for the amyotrophic lateral sclerosis group, form a unidimensional scale, supporting the use of a sum score as a measure of physical functioning within these diagnostic groups. When comparing the data of patients after stroke, with that of patients with multiple sclerosis and/or amyotrophic lateral sclerosis patients, adjustments for differential item functioning are required.     

Complete Recovery From Intractable Complex Regional Pain Syndrome, CRPS-Type I, Following Anesthetic Ketamine and Midazolam

Objective: To describe the treatment of an intractable complex regional pain syndrome I (CRPS-I) patient with anesthetic doses of ketamine supplemented with midazolam.
Methods: A patient presented with a rapidly progressing contiguous spread of CRPS from a severe ligamentous wrist injury. Standard pharmacological and interventional therapy successively failed to halt the spread of CRPS from the wrist to the entire right arm. Her pain was unmanageable with all standard therapy. As a last treatment option, the patient was transferred to the intensive care unit and treated on a compassionate care basis with anesthetic doses of ketamine in gradually increasing (3–5 mg/kg/h) doses in conjunction with midazolam over a period of 5 days.
Results: On the second day of the ketamine and midazolam infusion, edema, and discoloration began to resolve and increased spontaneous movement was noted. On day 6, symptoms completely resolved and infusions were tapered. The patient emerged from anesthesia completely free of pain and associated CRPS signs and symptoms. The patient has maintained this complete remission from CRPS for 8 years now.
Conclusions: In a patient with severe spreading and refractory CRPS, a complete and long-term remission from CRPS has been obtained utilizing ketamine and midazolam in anesthetic doses. This intensive care procedure has very serious risks but no severe complications occurred. The psychiatric side effects of ketamine were successfully managed with the concomitant use of midazolam and resolved within 1 month of treatment.
This case report illustrates the effectiveness and safety of high-dose ketamine in a patient with generalized, refractory CRPS.     

Interobserver reliability of diagnosis in patients with complex regional pain syndrome.

Complex regional pain syndrome type I (CRPS-I), formerly reflex sympathetic dystrophy (RSD), is a chronic pain syndrome of unknown aetiology. Its diagnosis is a clinical one, for which several criteria systems have been defined. Despite their widespread use, the reliability of these criteria has never been studied. In this interobserver study 25 chronic CRPS patients were interviewed and examined by six physicians. Through structured questionnaires signs, symptoms, and diagnosis were recorded, after which observer agreement for these was calculated with kappa statistics. Physicians' agreement in assessment of signs and symptoms in CRPS patients varied greatly. More importantly, final diagnosis of CRPS showed poor observer agreement (kappa: 0.20). The kappa values were higher, had physicians applied IASP criteria, but still insufficient. The application of Bruehl's criteria results in a fair kappa of 0.38, but then frequency of CRPS diagnosis in our study population decreased from 73% to 43% in comparison with physicians' own diagnosis. We conclude that, using current criteria systems, the diagnosis of CRPS is not reliable.     

Characteristics and period prevalence of self-induced disorder in patients referred to a pain clinic with the diagnosis of complex regional pain syndrome

INTRODUCTION: Although there have been a few case reports in the literature of self-inflicted symptoms presenting as complex regional pain syndrome (CRPS), there has been no systematic study. This report investigates the period prevalence and characteristics of self-induced disorders in patients referred to a comprehensive pain clinic with a diagnosis of CRPS. METHODS: Retrospective chart review was conducted for all cases referred as "neuropathic pain" to a comprehensive pain clinic over a period of 2 years. RESULTS: Out of 175 consecutive neuropathic pain referrals over a 2-year period, 41 were specifically referred as CRPS. Application of (modified) 1994 IASP CRPS criteria confirmed the diagnosis of CRPS in 11/15 men and in 15/26 women. Four of the 15 women had evidence of active self-induced signs and symptoms (eg, ligation of the limb, ulcerations, bizarre migrating wounds), which abated with casting, strict observation, discussion with the patient, or other intervention. The characteristics of these cases are presented and compared with other similar cases seen in previous years. CONCLUSIONS: This is the first report of a case series of patients diagnosed as CRPS with self-induced symptoms. We discuss in detail limitations of the study, factors that contribute to the index of suspicion, and the complex nature of the behavior including the overlap between factitious disorder, somatoform disorders, and malingering, whereas we stress the legitimacy of CRPS as a diagnosis.     

Spinal cord stimulation for complex regional pain syndrome: a systematic review of the clinical and cost-effectiveness literature and assessment of prognostic factors.

OBJECTIVE: To review the clinical and cost-effectiveness of spinal cord stimulation (SCS) in the management of patients with complex regional pain syndrome (CRPS) and identify the potential predictors of SCS outcome. DESIGN: Systematic review of the literature and meta-regression. METHODS: Electronic databases were searched for controlled and uncontrolled studies and economic evaluations relating to the use of SCS in patients with either CRPS type I or II. RESULTS: One randomised controlled trial, 25 case series and one cost-effectiveness study were included. In the randomised controlled trial in type I CRPS patients, SCS therapy lead to a reduction in pain intensity at 24 months of follow-up (mean change in VAS score -2.0), whereas pain was unchanged in the control group (mean change in VAS score 0.0) (p<0.001). In the case series studies, 67% (95% CI 51%, 84%) of type I and type II CRPS patients implanted with SCS reported pain relief of at least 50% over a median follow-up period of 33 months. No statistically significant predictors of pain relief with SCS were observed in multivariate meta-regression analysis across studies. An economic analysis based on the randomised controlled trial showed a lifetime cost saving of approximately 58,470 (60,800 US dollars) with SCS plus physical therapy compared with physical therapy alone. The mean cost per quality-adjusted life-year at 12-month follow-up was 22,580 (23,480 US dollars). CONCLUSIONS: SCS appears to be an effective therapy in the management of patients with CRPS type I (Level A evidence) and type II (Level D evidence). Moreover, there is evidence to demonstrate that SCS is a cost-effective treatment for CRPS type I.