Complex Regional Pain Syndrome/Reflex Sympathetic Dystrophy

ABSTRACT

Questions from patients about analgesic pharmacotherapy and responses from the authors are presented to help educate patients and make them more effective self-advocates. The topics addressed in this issue are the signs, symptoms, and diagnosis of complex regional pain syndrome/reflex sympathetic dystrophy.     

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.     

A Case of Complex Regional Pain Syndrome

ABSTRACT

A Case of complex regional pain syndrome is presented from the perspectives of pain specialists from the Czech Republic. Clinical presentation, goals of therapy, epidural analgesia, radiofrequency ablation, and nerve block, opioids and spinal cord stimulation are discussed. Commentaries on this case are provided by pain specialists from Israel and Sweden.     

Spinal Cord Stimulation (SCS) in Deafferentation Pain

Spinal cord stimulation is considered to be ineffective in relieving deafferentation pain. We have retrospectively analyzed the results obtained in a series of 41 patients. Sixteen suffered from pain associated with an incomplete traumatic spinaJ lesion, 15 from a posttherapeutic neuralgia, and 10 from pain due to root and/or nerve damage. At the end of the test period, 43.7% of the patients with paraplegic pain, (40% of those with peripheral deafferentation pain and 66.6% of the ones with postherapeutic neuralgia), reported satisfactory pain relief and were connected to a chronic stimulation system. At mean follow-up (15 months), only 20% of the patients of the first two groups reported sufficient pain relief In the postherapeutic group the figure of responders was unchanged. The mean analgesia achieved was 70%. From this analysis we conclude that the results achieved in the postherapeutic pain patients, although positive in only 66% of them, are remarkably stable with time. Therefore, we recommend a percutaneous test trial of SCS in every case of postherapeutic pain resistant to medical treatment.     

Spinal Cord Stimulation for Loin Pain Hematuria Syndrome: Clinical Report

Loin pain hematuria syndrome (LPHS) is a rare condition characterized by cryptogenic debilitating flank pain and microscopic or macroscopic hematuria. The pathophysiology of LPHS remains poorly understood, and diagnosis is made largely by exclusion of alternate pathology. Management strategies can vary widely and include chronic opioid medication and a variety of invasive procedures, including regional nerve blocks, transcutaneous electrical nerve stimulation, local capsaicin infusion, and surgical renal denervation. Neuromodulation may provide a new paradigm of treatment for LPHS, potentially sparing patients from long‐term complications of opiate therapy and invasive surgery. This report demonstrates the first case of successful symptomatic management of LPHS using spinal cord stimulation.     

Treatment of Complex Regional Pain Syndrome Type I With Oral Phenoxybenzamine: Rationale and Case Reports

▪ Abstract:   The nonselective α-adrenergic antagonist, phenoxybenzamine, has been used in the treatment of neuropathic pain syndromes, specifically, complex regional pain syndrome (CRPS) types I and II. This agent has also previously been used in intravenous regional peripheral blocks for treatment of CRPS I; however, an intravenous preparation of phenoxybenzamine is not currently available in the U.S.A. In this case series, systemic administration was more appropriate for three of the four patients, as their syndromes had spread beyond the initial area of surgery or trauma. We report an apparent clinical benefit in three of the four patients following oral administration. We postulate that this may be due to the noncompetitive (irreversible) blockade of α₁- and α₂-adrenergic receptors. We further hypothesize that this blockade could reduce stimulation of an increased population of adrenergic receptors in hyperalgesic skin, blunt the stimulation by norepinephrine of α₂-adrenergic receptors on macrophages, and ultimately reduce the release of proinflammatory cytokines from cellular elements. ▪     

16. Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy is a pain syndrome with an unclear pathophysiology and unpredictable clinical course. The disease is often therapy resistant, the natural course not always favorable. The diagnosis of CRPS is based on signs and symptoms derived from medical history and physical examination. Pharmacological pain management and physical rehabilitation of limb function are the main pillars of therapy and should be started as early as possible. If, however, there is no improvement of limb function and persistent severe pain, interventional pain management techniques may be considered. Intravenous regional blocks with guanethidine did not prove superior to placebo but frequent side effects occurred.Therefore this technique receives a negative recommendation (2 A–). Sympathetic block is the interventional treatment of first choice and has a 2 B+ rating. Ganglion stellatum (stellate ganglion) block with repeated local anesthetic injections or by radiofrequency denervation after positive diagnostic block is documented in prospective and retrospective trials in patients suffering from upper limb CRPS. Lumbar sympathetic blocks can be performed with repeated local anesthetic injections. For a more prolonged lumbar sympathetic block radiofrequency treatment is preferred over phenol neurolysis because effects are comparable whereas the risk for side effects is lower (2 B+). For patients suffering from CRPS refractory to conventional treatment and sympathetic blocks, plexus brachialis block or continuous epidural infusion analgesia coupled with exercise therapy may be tried (2 C+). Spinal cord stimulation is recommended if other treatments fail to improve pain and dysfunction (2 B+). Alternatively peripheral nerve stimulation can be considered, preferentially in study conditions (2 C+).     

Treatment of Refractory Ischemic Pain from Chemotherapy-Induced Raynaud's Syndrome With Spinal Cord Stimulation

Abstract:   We report the successful treatment of refractory ischemic pain from cisplatin-induced Raynaud's syndrome with spinal cord stimulation after failed pharmacologic management and surgical sympathectomy.
Case Report: A 48-year-old man developed ischemic pain of the hands while undergoing cisplatin and gemcitabine chemotherapy for metastatic pancreatic carcinoma. After extensive pharmacologic management and surgical sympathectomy failed to provide adequate analgesia, the patient underwent a percutaneous spinal cord stimulation trial followed by permanent implantation and received significant pain relief prior to succumbing to his illness. Spinal cord stimulation provided effective therapy for refractory ischemic pain, even after failed sympathectomy.     

Spinal Cord Stimulation (SCS) in Peripheral Ischemic Pain

Between 1982 and 1987,45 patients suffering from painful symptomatology caused by peripheral vascular disease, not curable by medical or surgical therapy, were implanted with epidural neurological stimulators. Measurements used in evaluating the effectiveness of the method were pain control, walking distance, and development of trophic problems. With most patients, we noted a satisfactory and long-lasting degree of pain control. Walking distance increased to a surprising degree. Trophic lesions smaller than 3 sq cm healed, while lesions of greater size required amputation of the limb. Transcutaneous oxygen tension (TcpO₂) was used to study the efects of SCS on peripheral circulation in implanted patients. In addition, TcpO₂ was calculated in 15 patients before and during the percutaneous test to predict the efectiveness of SCS. Regression of painful symptomatology was achieved only in patients whose TcpO_2b improved during the course of the testing. Therefore, this method provides an objective measure for the implantation of a neurostimulator     

脊髓电刺激治疗神经病理性疼痛的应用进展

脊髓电刺激(SCS)通过电脉冲信号阻断疼痛信号传递,干扰疼痛传导通路,激活阿片通道,刺激蓝斑系统及调节γ-氨基丁酸能系统,从而发挥抑制或减轻疼痛的作用。目前被应用于带状疱疹后神经痛、腰椎术后疼痛综合征、幻肢痛、痛性糖尿病神经病变、头面部神经痛、阴部神经痛等神经病理性疼痛的治疗中。     

Complex Regional Pain Syndrome (CRPS): Survey of Current Practices

Background and Objectives: There are numerous treatments for complex regional pain syndrome (CRPS). These treatments are varied in scope and include pain management therapies, psychological therapies, and physiotherapy. Treatment guidelines have been published in the past, but little information exists as to how clinicians utilize these guidelines. Moreover, there has been a paradigm shift from the older “reflex sympathetic dystrophy” (RSD) nomenclature, with largely sympathetic block driven diagnosis and therapy to more recent trends towards more inclusive “CRPS” diagnostic criteria and multidisciplinary treatment. There remains controversy regarding the selection of various techniques, and the timing of advancement through the treatment algorithm to the more aggressive, interventional techniques. We set out to determine current CRPS treatment practices of interventional pain specialists. Methods: The authors developed a 36‐item, 15–20‐minute questionnaire. This questionnaire was sent to 453 interventional pain specialists. Results: One‐hundred‐five surveys were returned, with 100 being complete. Eighty‐three percent of our respondents were practicing anesthesiology pain specialists who on average treat 14.9 (SD = 16.8) CRPS patients per month. Conclusions: Our survey results revealed the use of a treatment algorithm for CRPS that consists of treatment using medical therapies (pharmacologic, blocks, catheters, and implantable devices), psychological therapies, and physiotherapy in a coordinated fashion. The trend among our survey respondents is to utilize increasingly interventional techniques after a failed 2‐ to 4‐week trial of any one particular therapy.     

Outcome Prediction Following Sympathetic Block for Complex Regional Pain Syndrome

Abstract:   Evidence for the efficacy of sympathetic blocks as either diagnostic or therapeutic tools in complex regional pain syndrome (CRPS) remains anecdotal. Systematic evaluation has been confounded by inconsistent terminology, difficulties in objectively quantifying physical findings, and failure to control for co-morbid psychological factors. This study examines the relative contribution of physical and psychometric features as prospective predictors of outcome following sympathetic block in the treatment of CRPS. Twenty patients with CRPS characterized by mechanical allodynia and vasomotor/sudomotor disturbance were treated with sympathetic blocks. Long-term outcome was assessed at > 6 months following the last treatment using a mailed questionnaire. Pain relief and functional improvement were negatively influenced by anxiety ( P  < 0.001). When the improvement in the initial visual analog for pain (VAS) was 50% or greater following "diagnostic" sympathetic block, the percent improvement was highly correlated with improvement at long-term follow-up ( P  < 0.001). Higher "sensitivity" scores on the Neuropathic Pain Scale ( P  < 0.001), C fiber allodynia ( P  < 0.01) and Aδ-fiber allodynia ( P  < 0.01) on quantitative sensory testing, and pretreatment reported dynamic mechanical allodynia ( P  < 0.02) all predicted positive response to initial sympathetic block. While sympathetic blocks can be helpful in the reduction of mechanical allodynia, and thus the facilitation of physical and occupational therapy, ultimate response to a regime that includes medications is not predicted by sympathetic block alone.