Defining the therapeutic role of local anesthetic sympathetic blockade in complex regional pain syndrome: a narrative and systematic review

OBJECTIVE: There is growing controversy on the value of blocking the sympathetic nervous system for the treatment of complex regional pain syndromes (CRPS). The authors sought to evaluate the efficacy of sympathetic blockade with local anesthetic in these syndromes. In addition, they performed a comprehensive review of the pathophysiology and other treatments for CRPS. DESIGN: Systematic review of the literature was performed. MEDLINE was searched from 1966 through 1999. The authors identified only three randomized controlled trials (RCTs) that evaluated sympathetic blockade with local anesthetic, but because of differences in study design they were unable to pool the study data. The authors therefore included nonrandomized studies and case series. INTERVENTIONS: Studies were included if local anesthetic sympathetic blockade was used in at least 10 patients. Studies were excluded if continuous infusion techniques, somatic nerve blocks, or combined sympatholytic therapies were evaluated. OUTCOME MEASURES: Pain relief was classified as full, partial, or absent. The lack of a comparison group in the studies allowed only the calculation of distribution of the response categories, and the sum of the pooled rates does not equal 100%. RESULTS: Twenty-nine studies were included that evaluated 1,144 patients. Nineteen studies were retrospective, 5 prospective case series, 3 RCTs, and 2 nonrandomized controlled studies. The quality of the publications was generally poor. Twenty-nine percent of patients had full response, 41% had partial response, and 32% had absent response. It was not possible to estimate the duration of pain relief. CONCLUSIONS: This review raises questions as to the efficacy of local anesthetic sympathetic blockade as treatment of CRPS. Its efficacy is based mainly on case series. Less than one third of patients obtained full pain relief. The absence of control groups in case series leads to an overestimation of the treatment response that can explain the findings.     

Sphenopalatine Ganglion Block in the Management of Chronic Headaches

Purpose of Review

Sphenopalatine ganglion (SPG) block has been used by clinicians in the treatment of a variety of headache disorders, facial pain syndromes, and other facial neuralgias. The sensory and autonomic fibers that travel through the SPG provided the scientific rationale for symptoms associated with these head and neck syndromes. Yet, despite the elucidation of this pathogenic target, the optimal method to block its pain-producing properties has not been determined. Clinicians have developed various invasive and non-invasive techniques, each of which has shown variable rates of success. We examined the available studies of sphenopalatine ganglion blockade and its efficacy in the treatment of cluster headaches, migraines, and other trigeminal autonomic cephalalgias.

Recent Findings

Studies have demonstrated that SPG blockade and neurostimulation can provide pain relief in patients with cluster headaches, migraines, and other trigeminal autonomic cephalalgias. Patients with these conditions showed varying levels and duration of pain relief from SPG blockade. The efficacy of SPG blockade could be related to the different techniques targeting the SPG and choice of therapeutic agents.

Summary

Based on current studies, SPG blockade is a safe and effective treatment for chronic headaches such as cluster headaches, migraines, and other trigeminal autonomic cephalalgias. Future studies are warranted to define the optimal image-guided technique and choice of pharmacologic agents for SPG blockade as an effective treatment for chronic headaches related to activation of the sphenopalatine ganglion.

     

CT引导内脏与腹腔神经丛阻滞治疗上腹癌痛的比较

目的：观察CT引导下内脏与腹腔神经丛毁损性阻滞对上腹癌痛的镇痛效果比较。方法：48例顽固性上腹部癌症重度疼痛患者，随机分两组，在CT引导下分别行腹腔神经丛（Ｆ组）或内脏神经丛（Ｎ组）无水乙醇毁损阻滞治疗。观察两组镇痛效果、疼痛缓解程度及不良反应。结果：治疗后即刻全部患者疼痛减轻或消失。在治疗后第3、7、15、30、60、90天，患者的疼痛评分、疼痛程度均明显改善，两组间无显著差异，治疗过程中和治疗后未发生严重并发症。结论：内脏神经丛阻滞可取得与腹腔神经丛阻滞一致的效应，操作方便、疗效确切、安全性高，可供临床选择。     

An overview of neuropathic pain: syndromes,symptoms, signs,and several mechanisms

OBJECTIVE: An overview is presented of neuropathic pain syndromes, their characteristic symptoms and signs, and recent approaches to identifying their pathophysiologic mechanisms. DESIGN: The results of recent clinical studies of neuropathic pain are reviewed. Chronic neuropathic pain syndromes are emphasized because these long-lasting and often disabling conditions present a much greater challenge for the clinician than acute pain. Peripheral neuropathic syndromes have received greater attention in the research literature than central pain, and studies of syndromes such as postherpetic neuralgia and painful diabetic neuropathy provide the basis for current knowledge of neuropathic pain. CONCLUSIONS: Precise estimates of the prevalence of neuropathic pain are not available, but chronic neuropathic pain may be much more common than has generally been appreciated and its prevalence can be expected to increase in the future. There is considerable agreement that both peripheral and central processes contribute to many chronic neuropathic pain syndromes, and that these different mechanisms may explain the qualitatively different symptoms and signs that patients experience. The limitations of existing treatments for neuropathic pain and the inability to provide relief for many patients has stimulated ongoing studies that examine different approaches to preventing neuropathic pain.     

Chiropractic management of musculoskeletal pain in the multiple sclerosis patient

Multiple sclerosis (MS) is a common disabling disease. Five to 10% of MS patients will enter a long-term care facility. The majority of MS patients suffer from some type of pain syndrome. Pain syndromes in MS can be divided into three categories: acute; subacute or paroxysmal and chronic. Chronic pain syndromes have been anecdotally reported to respond to mechanical treatments. Chiropractic care has shown efficacy in the treatment of chronic spinal pain. Chiropractic care may represent a viable treatment option for the MS patient suffering from chronic pain syndromes. Chiropractic care has been successfully integrated into a chronic care facility which is affiliated with a private university medical school. Chiropractic has been utilized in this setting for pain management of MS patients suffering from chronic pain syndromes. Preliminary findings from this clinic suggest that chiropractic may represent one treatment alternative for chronic pain in MS patients in a long-term care facility. Further studies will be needed to definitively determine the efficacy of chiropractic for the management of chronic pain in the MS patient.     

Evaluation of patients for implantable pain modalities: medical and behavioral assessment

BACKGROUND: Advances in neurobiology serve as the basis for current and evolving implantable pain modalities, consisting of neurostimulation and neuraxial drug administration systems. Appropriate treatment of pain begins with an accurate diagnosis based on thorough physical and behavioral evaluations. MEASURES: The medical evaluation includes a review of the patient's medical history, diagnostic studies, physical examination, complete diagnostic workup, and screening trial of the proposed implantable therapy. The behavioral evaluation includes a review of the patient's history and medical records, clinical interview, mental status examination, psychological testing, and determination of suitability for implantation. CONCLUSIONS: Patients with chronic pain are subject to neurophysiological, emotional, and behavioral influences that govern their perception of pain and of pain relief. Therefore, treatment of chronic pain is multidisciplinary, drawing on cognitive and behavioral psychological therapies, functional rehabilitation, orthopedic and neurologic surgery, medications, nerve blockade, neuroaugmentative procedures, and sometimes neurodestructive procedures. Appropriate selection of patients helps ensure that implantable therapies are used for those who are most likely to benefit.     

Ultrasound‐Guided Transversus Abdominis Plane Catheter for Chronic Abdominal Pain

Abstract Background and Objectives: Neural blockade of the thoracolumbar nerves supplying the anterior abdominal wall through transversus abdominis plane (TAP) has been investigated for different applications mainly for the acute pain management following abdominal surgical procedures. The role of this block for chronic pain syndromes is still to be discovered, and its value in chronic abdominal pain needs to be studied. We are presenting new application of the TAP technique for management of chronic abdominal pain syndrome using the continuous infusion. Case report: We present a case of an 18‐year‐old girl who underwent an uneventful laparoscopic cholecystectomy. Postoperatively, patient complained of chronic pain at the site of the surgery. All diagnostic and imaging studies were negative for a surgical or a medical cause. Multiple interventions including epidural blocks, transcutaneous electrical neural stimulation, and celiac plexus blocks had failed to relieve the pain. After discussion with the patient about the diagnostic nature of the procedure and the likelihood of recurrence of pain, TAP block was performed on the right side with significant improvement of pain for about 24 hours. The degree of pain relief experienced by the patient was very dramatic, which encouraged us to proceed with an indwelling TAP catheter to allow for continuous infusion of a local anesthetic. The patient was sent home with the continuous infusion through a TAP catheter for 2 weeks. From the day of catheter insertion and up to 9 months of follow‐up, patient had marked improvement of her pain level as well as her functional status and ability to perform her daily activities, after which our acute pain team stopped following the patient. Conclusion: A successful TAP block confirmed the peripheral (somatic) source of the abdominal pain and provided temporary analgesia after which an indwelling catheter was inserted, which provided prolonged pain relief.     

Chronic pain syndromes in the emergency department: identifying guidelines for management

Objectives: To explore current literature on chronic pain syndromes and develop ED recommendations for the management and minimalization of chronic non‐cancer pain. Methods: A focused literature review. Results: Chronic pain is a common presentation to the ED but is poorly understood and managed. Research into the psychophysiology of chronic pain shows that there are definite changes in the receptive and processing pathways in patients suffering chronic pain syndromes. Evidence shows the effectiveness of early recognition with multimodal treatment, however high level evidence is lacking. All experts recommend balanced drug therapy, cognitive and behavioural interventions. Certain interventions are appropriate to the ED setting. Conclusions: Emergency Medicine lacks a cohesive, informed strategy for management of chronic pain. The proposed guidelines represent the first step toward establishing consistency in the management of patients with chronic pain syndromes. Further work needs to be undertaken at a national level in developing evidence based guidelines.     

Prognostic values of physical examination findings in patients with chronic low back pain treated conservatively: a systematic literature review

BACKGROUND: Most patients undergo physical examination. However, low back pain can only rarely be clearly diagnosed as having an irrefutable pathoanatomic cause on the basis of the classical battery of noninvasive physical examination procedures. However, physical examination findings are also used to predict the prognosis of treatment of chronic low back pain. A systematic review of the clinical literature is needed for an understanding of findings in this area. OBJECTIVES: To establish whether various physical examination procedures can be used to predict treatment outcome in the conservative (noninvasive) treatment of chronic low back pain. Data Sources: From 910 titles published between 1986 and 1998, 10 original research reports were selected. These were obtained by means of a computerized MEDLINE search through use of various combinations of the key words low back pain, treatment, physical findings, predictors, prognosis, prognostic factors, prognostic indicators, and predictors and outcome(s); manual search strategies were also used. Data Synthesis: Articles that fitted the objectives of this review were retained and systematically reviewed for the prognostic value of the relevant tests/observations. In addition, results were studied in relation to type of outcome variable and type of treatment. RESULTS: The most commonly investigated tests were lumbar range-of-motion tests, which were found to have a clear-cut significant predictive value in 3 of 9 studies. Further analyses in relation to definition of outcome (back-to-work or reduction of symptoms) were not possible because study results were usually not clearly reported for each definition and because therapies were multimodal rather than distinctly well defined. CONCLUSIONS: This area has not been fully investigated. Therefore, there is no satisfactory answer to the question of whether some physical examination tests have a prognostic value in the conservative treatment of chronic low back pain.     

Neural Modulation by Blocks and Infusions

Abstract:   Neural blockade is widely used in clinical practice to alleviate acute or chronic pain, including neuropathic pain. However, to date there is little controlled evidence to confirm the efficacy of nerve blocks in neuropathic pain. The most common indication for nerve blocks, especially sympathetic blockade, is complex regional pain syndrome, in which success rates of up to 38% have been achieved, depending on the type of the block used. Greater efficacy has been achieved by combining a nerve block with patient-controlled analgesia. Sympathectomy is recommended for the treatment of neuropathic pain only after careful consideration of its usefulness, effectiveness, and risk of adverse effects. Current evidence and clinical experience suggest that neural blockade could be a useful adjunct in the management of refractory neuropathic pain, but further well-controlled studies would be of great benefit to support this type of therapy.     

Local therapy with capsaicin or ASS in chronic pain

OBJECTIVE: To provide a brief review of the current state of topical treatment with capsaicin or acetylsalicylic acid (ASA) for therapy of chronic pain syndromes. DATA SOURCES: A MEDLINE search was used to find the pertinent literature on "capsaicin" or "ASA" and "chronic pain"; further publications found in these articles were added. CONCLUSIONS: Capsaicin is a white crystalline parent compound of a group of vanillyl fatty acid amines. Because of its highly specific action in neurons it has become an important tool in neuroscience. Because of its effects, it is obvious to try for the therapy of circumscribed neuropathic pain. Capsaicin acts by depleting stores of substance P and other neurotransmitters, resulting in a blockade of a specific group of sensory afferents. The corresponding clinical findings are initial burning and a desensitization of specific C fiber nociceptors after repeated application. The pain relieving potency was observed in various clinical investigations and even in a few controlled, double-blind studies about neuropathic pain syndromes and (osteo)arthritis. In contrast to these findings, a recent study found no significant benefit of capsaicin, probably because this study was the first to use an active placebo. Therefore, and because clinical efficacy and advantages over other therapies have not been demonstrated up to now, capsaicin cannot be classified as standard therapy. It may be a therapeutic option as an alternative or as an adjuvant treatment. Pain reduction was also observed after topical application of ASA/ether mixture in the one and only controlled double-blind study on this issue. Therefore, topical ASA therapy for (post)herpetic neuralgia is mainly based on a few enthusiastic case reports rather than on well founded investigations. Furthermore, the discrimination of local from systemic effects, the toxicological profile of longterm topical treatment, and the mechanism of action has not been evaluated. In conclusion, topical ASA cannot be recommended for routine clinical use at present.     

Increasing the efficacy of a celiac plexus block in patients with severe pancreatic cancer pain.

The purpose of this study was to evaluate the technical possibilities of placing a catheter near the celiac plexus for performance of a celiac plexus block, and to study the efficacy of repeated neurolytic celiac plexus blocks with alcohol in patients with advanced pancreatic cancer pain resistant to opioid treatment. In 12 patients, a neurolytic celiac plexus block with alcohol, administered via an indwelling celiac catheter, was performed. To evaluate the efficacy, visual analog scale scores were recorded every day. Quality of life scores were registered before and 4 weeks following the procedure. Alterations in opioid consumption, and the time between the diagnosis of pancreatic cancer and the performance of the block, were registered. All patients were followed until they died. Two patients remained without pain after the first neurolytic celiac plexus block. In all other patients a second block was administered which provided only temporary relief. Additional intermittent administration of bupivacaine through the catheter was necessary to provide adequate pain relief in these patients. Quality of life increased significantly during the treatment. Opioid consumption decreased significantly in all patients. Our study indicates that a neurolytic celiac plexus blockade with alcohol results in a significant but short-lasting analgesic effect. The use of a celiac catheter improves the long-term management of pancreatic cancer pain.     

The use of benzodiazepines in the treatment of chest pain: a review of the literature

Benzodiazepines, although not listed in the American Heart Association's guidelines for the treatment of chest pain, are often used to provide symptomatic relief to patients who experience chest pain. To investigate the utility of benzodiazepines in the treatment of chest pain, the pharmacologic actions and cardiovascular effects of benzodiazepines were reviewed. In addition, a literature search regarding the use of benzodiazepines to treat patients with chest pain was conducted. The results indicated that benzodiazepines reduce anxiety, pain, and cardiovascular activation. Benzodiazepines amplify gamma-aminobutyric acid (GABA) throughout the central nervous system, and act more peripherally to reduce catecholamines. In addition, preliminary evidence indicates that benzodiazepines may cause coronary vasodilatation, prevent dysrhythmias, and block platelet aggregation, though further study is needed. Both non-cardiac chest pain (associated with musculoskeletal, esophageal, neurologic, and psychiatric conditions) and cardiac chest pain (associated with acute and chronic myocardial ischemia) seem to be effectively treated with benzodiazepines. Benzodiazepines are safe and well tolerated when administered alone or in combination with other medications. Moreover, the risk of dependence is minimal when benzodiazepines are prescribed on a short-term basis. Further study of benzodiazepines in the treatment of acute chest pain is needed to confirm these favorable actions and better define their use in the acute medical setting.     

Cancer pain treatment with nerve blocks and neuroablative procedures

The management of opioid resistant cancer pain is a significant issue for palliative medicine. Certain types of pain can be relieved effectively using nerve blocks without exacerbating and sometimes improving daily activity as long as proper patient selection and technique are employed. Continuous epidural and subarachnoid block, celiac plexus block, superior hypogastric plexus block, subarachnoid phenol block and percutaneous cervical cordotomy are common pain treatment procedures. In our pain clinic, these procedures were performed on about 20% of cancer pain patients, most of whom experienced pain relief without serious complications. Proper use of nerve blocks and neuroablative procedures can undoubtedly improve the management of cancer pain and should be a significant component of the strategy for cancer pain relief.     

Sphenopalatine Ganglion Pulsed Radiofrequency Treatment in 30 Patients Suffering from Chronic Face and Head Pain

Abstract:   This study evaluated the efficacy of sphenopalatine ganglion pulsed radiofrequency (SPG-PRF) treatment in patients suffering from chronic head and face pain. Thirty patients were observed from 4 to 52 months after PRF treatment. The primary efficacy measures were the reduction in oral medication use, including opioids, time-to-next-treatment modality for presenting symptoms, duration of pain relief, and the presence of residual symptoms. Secondary objectives included the evaluation of adverse effects and complications. All data were derived from patient charts, phone conversations, and clinical follow-up visits. Fourteen percent of respondents reported no pain relief, 21% had complete pain relief, and 65% of the patients reported mild to moderate pain relief from SPG-PRF treatment. Sixty-five percent of the respondents reported mild to moderate reduction in oral opioids. None of the patients developed significant infection, bleeding, hematoma formation, dysesthesia, or numbness of palate, maxilla, or posterior pharynx. A large-scale study of SPG-PRF for the treatment of face and head pain has not been previously reported. Our results suggest that a prospective, randomized, controlled trial study to confirm efficacy and safety of this novel treatment for chronic head and face pain is justified.     

Antitumor and antinociceptive approaches to control cancer pain

Patients with cancer pain often present with specific clinical syndromes that allow specific anti-tumor approaches. If these approaches are not feasible, neurosurgical procedures for pain relief should be considered. The major advantage of neurosurgical procedures is freedom from the excessive side effects of narcotic therapy. The most durable pain procedure is cordotomy, while intraspinal narcotics offer a rational treatment alternative in selected patients. Spinal and plexopathy syndromes that are amenable to more specific anti-tumor therapy should be looked for, since newer surgical approaches offer the prospect of both pain relief and tumor control.     

Long-term Results of Radiofrequency Rhizotomy in the Treatment of Cluster Headache

Although the primary treatment of chronic cluster headache is medical, surgical treatment is sometimes used. The authors reviewed the charts of seven patients (ages 36 to 68 years) with chronic cluster headache to identify who responded best to percutaneous stereotactic radiofrequency rhizotomy after medical treatment failed. All patients had immediate pain relief after surgery. At follow-up (median 5 years, range 2 to 20 years), two patients remained pain-free 7 and 20 years later (excellent results); three patients had mild pain recurrence that was well controlled on medications (good results) 6 to 12 months after surgery; and two patients had major pain recurrence 4 days and 2 months after surgery (poor results). Six patients had relief of vasomotor symptoms. One patient had transient diplopia and keratitis without permanent sequelae. Both patients with excellent results had pre-operative major pain around the eye; both patients with poor results had major pain around the temple, ear, and cheek; and the three patients with good results had pain equally severe in the eye, temple, and cheek. There was no association between patient age or sex, pain duration, preoperative response to lidocaine blockade, or previous surgery with pain relief. No differences occurred in pain relief between patients with dense hypalgesia and patients with analgesia. The authors conclude that (1) some patients with chronic cluster headache treated by percutaneous stereotactic radiofrequency rhizotomy achieve long-term pain relief, and (2) surgery on the trigeminovascular system alone may not cure the condition in patients with major pain around the temple, ear, and cheek.     

Transcutaneous Application of Pulsed Radiofrequency Treatment for Shoulder Pain

We report a retrospective audit of transcutaneous pulsed radiofrequency treatment therapy (TCPRFT) for shoulder pain over a 4‐year period. Methods: Electronic and manual case review revealed that TCPRFT had been performed on 13 patients, with 15 painful shoulders, using a single treatment session between 2006 and 2010 in an outpatient setting. Results: Of the 15 shoulders treated, 10 (two‐thirds) had pain relief for over 3 months with an average pain score reduction of 6.1 of 10 and an average duration of pain relief of 395 days. Two experienced pain relief of < 3 months with an average reduction in pain score of 4.3 of 10 and an average duration of effect of 11 days. Three cases experienced no pain relief from the treatment. Summary: These results suggest TCPRFT may provide clinically useful pain relief and be another treatment modality for shoulder pain. Our findings justifies further research, and we are proceeding with a double‐blind placebo randomized controlled studies to determine the efficacy of TCPRFT in chronic shoulder pain.