Results of a patient survey for an implantable neurostimulator to treat migraine headaches

Migraine attacks are believed to involve activation of the trigeminovascular system and trigeminal-parasympathetic reflex, which is mediated through the sphenopalatine ganglion (SPG). An implantable SPG neurostimulator has been developed to apply on-demand SPG stimulation for the treatment of severe primary headache. The neurostimulator is implanted via an oral incision and placed along the maxilla, with the lead placed at the SPG. The neurostimulator contains no battery and is powered and controlled via a handheld remote controller. The potential interest of patients with high-frequency, high-disability migraine in having a SPG neurostimulator implanted to treat migraine is unknown. We aimed to evaluate patient interest to undergo such an implantation procedure and to participate in a clinical investigation of on-demand SPG stimulation for migraine by conducting a survey at the Ghent University Hospital in 41 migraineurs. Seventy-seven percent (77%) of subjects expressed an interest in participating in a clinical investigation requiring implantation of a SPG neurostimulator when headache frequency and severity were considered and 69% when pain relief experienced with current migraine treatment was considered. Preventive and acute medications were used in 64 and 95% of the subjects, respectively, and provided a reported reduction of headache frequency, duration and pain. However, acute medications were frequently associated with headache recurrence and bothersome side effects. Results indicate that a majority of high-frequency, high-disability migraineurs, many of whom achieve pain relief with their current medications, have an interest in participating in a clinical investigation of an implantable SPG neurostimulator for the treatment of migraine headache.     

Anesthesia (3)

Complex regional pain syndrome (CRPS) with resistance to local anesthetic block: a case report. (State University of New York at Stony Brook, Stony Brook, NY) J Clin Anesth 2000;12:67–71.
A case of complex regional pain syndrome (CRPS) Type 1 in a 12-year-old girl is presented. The patient did not respond to the usual therapeutic modalities used to treat CRPS including physical therapy, lumbar sympathetic block, epidural local anesthetic block, intravenous lidocaine infusion, or other oral medications. Of note is the fact that during epidural block the patient demonstrated a resistance to local anesthetic neural blockade in the area of the body involved with the pain problem. The mechanism of this resistance could be related to the changes in the dorsal horn cells of the spinal cord, secondary to activation of N-methyl-D-aspartate receptors, which may play a role in the pathophysiology of this pain syndrome.     

The treatment of complex regional pain syndrome type I with free radical scavengers: a randomized controlled study

To compare the effects of two free radical scavengers, dimethylsulfoxide 50% (DMSO) and N-acetylcysteine (NAC), for treatment of complex regional pain syndrome I (CRPS I), a randomized, double-dummy controlled, double-blind trial was conducted. Two outpatient clinics of two university hospitals in The Netherlands participated in the study and 146 patients, were included over a period of 24 months. Patients were randomized into two treatment groups, one was instructed to apply DMSO 50% five times daily to the affected extremity, the second was treated with NAC 600mg effervescent tablets three times daily, both combined with placebo. Interventions were accompanied by pain medication, occupational therapy for upper extremity CRPS I and physical therapy for lower extremity CRPS I in specific circumstances. Treatment was given for 17 weeks, with a possibility to continue or switch medication after this period, up to 1 year following the onset of treatment. An impairment level sum score was the primary outcome measure. Upper and lower extremity skills and functions, and general health status were also evaluated. Overall, no significant differences were found between NAC and DMSO after 17 and 52 weeks on impairment level and general health status. Significant differences were found for subscores of lower extremity function, in favor of DMSO-treatment. Subgroup analysis showed more favorable results for DMSO for warm CRPS I and significantly better performance of NAC for patients with a cold CRPS I. Results tended to be negatively influenced if the duration of the complaint was longer. Treatment with DMSO and NAC are generally equally effective in treatment of CRPS I. Strong indications exist for differences in effects for subgroups of patients with warm or cold CRPS I: for warm CRPS I, DMSO-treatment appears more favorable, while for cold CRPS I, NAC-treatment appears to be more effective.     

Pharmacologic management of complex regional pain syndrome

Few randomized controlled trials of oral pharmacotherapy have been performed in patients with complex regional pain syndrome (CRPS). The prevalence of CRPS is uncertain. Severe and advanced cases of CRPS are easily recognized but difficult to treat and constitute a minority compared with those who meet minimum criteria for the diagnosis. Unsettled disability or liability claims limit pharmaceutical industry interest in the disorder. Many studies are small or anecdotal, or are reported on only via posters at meetings. Targeting the process of bone resorption with bisphosphonate-type compounds such as calcitonin, clodronate, and alendronate has shown efficacy in three published randomized controlled trials. Intravenous phentolamine has been studied both alone and in comparison to intravenous regional blockade or stellate ganglion block. Steroids continue to be administered by multiple routes without large-scale placebo-controlled trials. Topical medications have received little attention. There has been considerable interest in the use of thalidomide and TNF-alpha blockers for CRPS, but no published controlled trials as of yet. Numerous other oral drugs, including muscle relaxants, benzodiazepines, antidepressants, anticonvulsants, and opioids, have been reported on anecdotally. Some therapies have been the subject of early controlled studies, without subsequent follow-up (eg, ketanserin) or without an analogous well-tolerated and equally effective oral treatment (eg, intravenous ketamine). Gabapentin, tricyclic antidepressants, and opioids have been proven effective for chronic pain in disorders other than CRPS. Each has shown a broad enough spectrum of analgesic activity to be cautiously recommended for treatment of CRPS until adequate randomized controlled trials settle the issue. The relative benefit of oral medications compared with the widely used treatments of intensive physical therapy, nerve blocks, sympathectomy, intraspinally administered drugs, and neuromodulatory therapies (eg, spinal cord stimulation) remains uncertain. In summary, treatment of CRPS has received insufficient study and remains largely empirical.     

The incidence of complex regional pain syndrome: a population-based study

The complex regional pain syndrome (CRPS) is a painful disorder that can occur in an extremity after any type of injury, or even spontaneously. Data on the incidence of CRPS are scarce and mostly hospital based. Therefore the size of the problem and its burden on health care and society are unknown. The objective of the present study was to estimate the incidence of CRPS in the general population. A retrospective cohort study was conducted during 1996-2005 in the Integrated Primary Care Information (IPCI) project, a general practice research database with electronic patient record data from 600,000 patients throughout The Netherlands. Potential CRPS cases were identified by a sensitive search algorithm including synonyms and abbreviations for CRPS. Subsequently, cases were validated by electronic record review, supplemented with original specialist letters and information from an enquiry of general practitioners. The estimated overall incidence rate of CRPS was 26.2 per 100,000 person years (95% CI: 23.0-29.7). Females were affected at least three times more often than males (ratio: 3.4). The highest incidence occurred in females in the age category of 61-70 years. The upper extremity was affected more frequently than the lower extremity and a fracture was the most common precipitating event (44%). The observed incidence rate of CRPS is more as four times higher than the incidence rate observed in the only other population-based study, performed in Olmsted County, USA. Postmenopausal woman appeared to be at the highest risk for the development of CRPS.     

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.     

Intravenous regional block with lidocaine for treatment of complex regional pain syndrome

OBJECTIVES: The goal of this article is to report the successful treatment of a patient with complex regional pain syndrome (CRPS) type 1 involving the hand with the use of an intravenous regional block. METHODS: The patient was a 35-year-old woman who developed CRPS during conservative therapy for a metacarpal fracture. An intravenous regional block with lidocaine alone, using a two-tourniquet technique, was delivered 10 times for at least 40 minutes. The first five treatments were given twice a week and the next five were delivered weekly. All affected joints, including the wrist, were manipulated without undue force. Functional physical measurements were assessed, including range of motion and performance of fine and gross motor tasks. RESULTS: The visual analog scale scores for pain declined from 10 to 0 after treatment. Use of a pen, a pair of chopsticks, and a hammer improved, and edema decreased. CONCLUSIONS: Intravenous regional block with lidocaine was well tolerated and associated with relief in this case of CRPS type 1.     

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.     

Polycythemia vera presenting as complex regional pain syndrome of the lower limbs

CASE REPORT: A 73-year-old woman with bilateral severe pain in her legs and feet was admitted to the hospital. The pain had started spontaneously without any known trauma a year earlier and had progressively worsened to the point that she was unable to walk. The patient complained of pain, discoloration, and sweating of the lower extremities. Physical examination revealed swollen, cold, wet, and blue extremities, with both allodynia and hyperalgesia, fulfilling criteria for a diagnosis of complex regional pain syndrome (CRPS) type 1. Laboratory findings demonstrated a hemoglobin level of 180 g/L(-1) and a hematocrit of 47%, leading to a diagnosis of polycythemia vera (PCV). Her condition slowly improved after repeated venesection, mild analgesics, and amitriptyline. CONCLUSIONS: Polycythemia vera has not been described previously as a contributing factor in CRPS. In the present case, the diagnosis of PCV was important, because its treatment also improved the CRPS.     

Amenorrhea in a patient after treatment with gabapentin for complex regional pain syndrome type II

A 35-year-old woman suffered a traumatic injury to her right sciatic nerve requiring nerve exploration and external neurolysis. Following the surgery, the patient developed complex regional pain syndrome (CRPS) type II and was treated with gabapentin for pain control. Three months after the initiation of gabapentin therapy (1800 mg/day), the patient reported complete cessation of her menses. Based on hormonal tests, her gynecologist concluded that her amenorrhea was secondary to gabapentin therapy. The patient was weaned off the gabapentin over 6 days with return of her menses 2 weeks later. I conclude that gabapentin has the potential to cause amenorrhea with return of menses occurring after discontinuation of the drug.     

A Severe Case of Complex Regional Pain Syndrome I (Reflex Sympathetic Dystrophy) Managed with Spinal Cord Stimulation

Complex regional pain syndrome is a condition that usually affects the upper or lower extremities. The cause is not clearly understood. We report a case of a severe form of a rapidly progressive complex regional pain syndrome type I developing after a right shoulder injury managed with spinal cord stimulation (SCS). After failed conservative treatments, a rechargeable SCS system was implanted in the cervical spine. Allodynia and dystonia improved but the patient subsequently developed similar symptoms in lower right extremity followed by her lower left extremity. The patient became wheelchair bound. A second rechargeable SCS with a paddle electrode was implanted for the lower extremity coverage. The patient's allodynia and skin lesions improved significantly. However, over time, her initial symptoms reappeared which included skin breakdown. Due to the need for frequent recharging, the system was removed. During explantation of the surgical paddle lead, it was noted by the neurosurgeon that the contacts of the paddle lead were detached from the lead. After successful implantation of another SCS system, the patient was able to reduce her medications and is now able to ambulate with the use of a left elbow crutch.     

Burst Spinal Cord Stimulation in a Patient with Complex Regional Pain Syndrome: A 2‐year Follow‐Up

Spinal cord stimulation (SCS) is an effective therapy to treat most patients with complex regional pain syndrome (CRPS); however, the effect is not always maintained over time. We present a case report of a patient successfully treated with burst SCS after a diminishing effect of conventional tonic stimulation. Burst stimulation is a novel method of SCS consisting of delivering 5 spikes at 500 Hz, 40 times/s (pulse width 1 mseconds). The current output is set to a subthreshold level for paresthesia in the supine position. Report of a case: A 65‐year‐old woman with CRPS in the left upper extremity experienced a diminishing effect of conventional tonic SCS over time, resulting in an increase of pain with a mean Numerical Rating Score (NRS) of 8. After treatment with burst SCS, the NRS declined to 2 and remained at that level for 2 years. An intermediate/brief period, due to increased CRPS activity, resulted in a higher pain score, which was successfully managed by increasing the burst stimulation to a higher level of subthreshold stimulation. Discussion: In this patient with CRPS, burst SCS was successful in reducing pain scores that could no longer be achieved with conventional tonic stimulation. It appears that pain reduction with burst SCS can be sustained for a relatively long period of time.     

Long-term relief of posttraumatic headache by sphenopalatine ganglion pulsed radiofrequency lesioning: a case report

Posttraumatic headache is a common and disabling pain syndrome in patients who sustain a head injury. Unfortunately, conventional treatments may fail or cause intolerable side effects. Because chronic headache may be mediated by central and peripheral neural processes, these structures may be therapeutic targets. One target, the sphenopalatine ganglion (SPG), is implicated in several headache disorders and has been lesioned for headache relief. Because of the risks of neurolytic procedures, nonablative procedures that provide pain relief would be useful. We present a case wherein a man in his late twenties with posttraumatic headache obtained more than 17 months of relief with SPG pulsed-mode radiofrequency lesioning. SPG pulsed-mode radiofrequency is a nonablative, neural lesioning method that may be useful in the treatment of posttraumatic headache.     

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.     

Sphenopalatine ganglion block: clinical use in the pain management clinic

Clinical experience with the sphenopalatine ganglion (SPG) block combined with a review of prior studies led to conducting a retrospective evaluation of four patients with chronic pain treated with the SPG block. The review of case reports suggests the usefulness of SPG blocks in the pain management clinic.     

Impairment level SumScore for lower extremity Complex Regional Pain Syndrome type I

Objectives : To construct a single indicator on impairment level for lower extremity Complex Regional Pain syndrome type I (CRPS I).

Design : The Impairment level SumScore (ISS) for upper extremity CRPS I was adapted to be used for lower extremity evaluation. Medline literature search and research findings were used to adapt the upper extremity version of the ISS, with emphasis on reliability, responsiveness and validity of measurement instruments. Where needed, additional patient data was gathered to evaluate these aspects for different measurement instruments.

Setting : An outpatient clinic of a university hospital in the Netherlands.

Participants : Two groups consisting of 17 and 26 healthy volunteers, and two groups of respectively 40 and 18 lower extremity CRPS I patients according to Veldman's criteria.

Main outcome measures : VAS and McGill pain scores, water displacement volumeter values, and physicians' and patients' assessment of CRPS I severity.

Results : A combination of measurements, incorporating pain (VAS and McGill), temperature (infrared thermometer), volume (water displacement volumeter) and active range of motion (universal goniometer), was converted in a single score ranging from 5 to 50. The reliability, as well as the responsiveness was adequate.

Conclusions : The lower extremity ISS permits evaluation of the most prominent symptoms in CRPS I, and can be used to monitor changes in CRPS I.     

Long-term skin temperature measurements - a practical diagnostic tool in complex regional pain syndrome

Despite the development of the IASP criteria, diagnosing complex regional pain syndrome (CRPS) remains a challenge because all symptoms vary interindividually, including the vascular abnormalities. Previous studies showed that skin temperature asymmetries between the affected and contralateral extremity around 2 degrees C are useful for diagnosing CRPS. However, they were either assessed only at one single point in time or during specific investigations including controlled thermoregulatory modulation of sympathetic activity which limits their practicability. The present study evaluated long-term skin temperature changes under everyday circumstances in 22 patients with CRPS, 18 patients with limb pain of other origin and 23 healthy controls. The asymmetries in skin temperature and oscillation number (Q Oscill), the percentage of assessed time with a-synchron temperature changes on both body sides and the determination coefficient of the individual regression (r2 id) were compared between the groups. Patients with CRPS differed significantly from healthy controls in nearly all parameters. Minor differences between both patient groups were found regarding the percentage of assessed time with side difference >2 degrees C (DeltaT2). However, both patient groups differed significantly in parameters characterizing the skin temperature dynamics. A sum score (2 *Q Oscill +r2 id +DeltaT2) allowed diagnosing CRPS with a specificity of 67% vs. patients with other painful diseases and 79% vs. healthy controls (sensitivity: 73%, respectively, 94%) and reflected the severity of the dysfunction in CRPS better than the mean skin temperature side differences alone. The applied skin temperature analysis can be easily applied in the clinical settings and serves as a further facet in the difficult diagnosis of CRPS.     

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.     

Lenalidomide for Complex Regional Pain Syndrome Type 1: Lack of Efficacy in a Phase II Randomized Study

Complex regional pain syndrome (CRPS) is a potentially debilitating chronic pain syndrome with a poorly understood but likely neuroimmune/multifactorial pathophysiology associated with axonal injury. Based on the potential contribution of proinflammatory cytokines to CRPS pathogenesis and prior research with thalidomide, we investigated lenalidomide, a thalidomide derivative, for CRPS treatment. We conducted a phase II, randomized, double-blind, placebo-controlled study to evaluate the efficacy of oral lenalidomide 10 mg once daily in consenting patients with unilateral or bilateral CRPS type 1. The study comprised 12 weeks of treatment followed by a long-term extension. The primary efficacy outcome was reduced pain in the index limb, defined as ≥30% improvement from baseline using an 11-point numeric rating scale. One hundred eighty-four subjects enrolled. The primary endpoint was not met because equal proportions of treated (16.1%) and control (16.1%) subjects achieved the outcome; however, lenalidomide was well tolerated, with no evidence of neuropathy or major adverse effects. This study is the largest controlled, blinded clinical trial in subjects with chronic CRPS using the Budapest research criteria. It demonstrates the feasibility of conducting high-quality clinical trials in CRPS type 1 and provides considerations for designing future trials.PerspectiveThis article reports an adequately powered, controlled clinical trial in subjects with CRPS. Treatment and placebo were equally effective, but the study demonstrated that lenalidomide treatment is feasible in this population. The study provides examples to consider in designing future CRPS trials.     

Bier block as a successful management of a patient with intractable complex regional pain syndrome (CRPS) type 1: A case report

Bier block was successful in the pain management of complex regional pain syndrome (CRPS) type 1.