RESUMO
BACKGROUND: There is ongoing controversy regarding the validity of controlled diagnostic blocks due to variability in sensitivity, specificity, and accuracy. Consequently, identification of false-positive rates, false-negative rates, and placebo responses is crucial. The reasons described for false-positive responses to diagnostic anesthetic blocks are many; however, sedation and psychological factors have been implied as causes. Further, there is no consensus with regards to sedation prior to controlled diagnostic blocks and their influence on the accuracy and validity of a diagnosis. STUDY DESIGN: A systematic review of the literature evaluating the influence of sedation on diagnostic spinal interventional techniques. OBJECTIVES: To systematically assess the quality of clinical studies evaluating the diagnostic accuracy of controlled diagnostic blocks in the diagnosis of chronic spinal pain. METHODS: A comprehensive evaluation of the literature relating to sedation in diagnostic interventional techniques was performed. The methodologic quality assessment of the studies was carried out by utilizing Agency for Healthcare Research and Quality (AHRQ) methodologic quality criteria with scores of 50 or higher included in the assessment of the level of evidence. Level of evidence was based on the U.S. Preventive Services Task Force (USPSTF) criteria for the assessment of accuracy of diagnostic studies. LIMITATIONS: All 3 of the studies were produced by one group of authors. Thus paucity of the literature on the subject of facet joint pain and the lack of literature on the subjects of discogenic pain and sacroiliac joint pain are major limitations. RESULTS: Three studies were identified which met inclusion and methodologic assessment quality criteria. Sedation can be a confounding factor in a small population of patients specifically if fentanyl is employed and non-stringent criteria are followed. Based on the 3 randomized double-blind trials with stringent criteria utilizing 80% pain relief and the ability to perform prior painful movements without any significant pain following the diagnostic injection in evaluation of facet joint pain, the indicated evidence is Level II-1. CONCLUSION: This systematic review provides no significant evidence of the influence of sedation either with midazolam or fentanyl in the evaluation of cervical and lumbar facet joint pain with controlled cervical and lumbar facet joint nerve blocks with an indicated evidence of Level II-1, with application of stringent criteria of at least 80% pain relief and the ability to perform previously painful movements after the diagnostic blocks.
Assuntos
Anestesia/métodos , Hipnóticos e Sedativos , Coluna Vertebral/efeitos dos fármacos , Humanos , Hipnóticos e Sedativos/uso terapêutico , Injeções Espinhais , Coluna Vertebral/patologiaRESUMO
BACKGROUND: Disability, societal, and health impact of chronic intractable pain secondary to various failed therapies is a major issue. As advanced therapy, implantable therapies, which include intrathecal devices and spinal cord stimulation systems, are frequently used in managing chronic intractable pain. Thus, continuous infusion of intrathecal medication is one of the methods used for the control of chronic, refractory, cancer, and non-cancer pain. However, despite the high costs of chronic non-cancer pain, it has been claimed that there is a lack of evidence for intrathecal infusion systems and the cost effectiveness of these systems has been questioned in improving pain and function. STUDY DESIGN: A systematic review of intrathecal infusion devices for chronic non-cancer pain. OBJECTIVE: To determine the efficacy, utilization, safety, and complications associated with the use of intrathecal infusion devices for long-term management of chronic non-cancer pain. METHODS: Literature search was performed through EMBASE, Medline, Cochrane databases, and systematic reviews identified from 1966 to December 2008. Studies were then reviewed and assessed using the Agency for Healthcare Research and Quality (AHRQ) criteria for observational studies and the Cochrane Musculoskeletal Review Group criteria for randomized trials. The level of evidence was determined using 5 levels of evidence, ranging from Level I to III with 3 subcategories in Level II, based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). OUTCOME MEASURES: The primary outcome measure was pain relief (short-term relief < or = one-year and long-term > one-year). Secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake were also utilized. RESULTS: The level of evidence for intrathecal infusion systems indicated either Level II-3 or Level III (limited) based on U.S. Preventive Services Task Force (USPSTF) criteria. LIMITATIONS: The limitations of this study include the paucity of literature, lack of quality evidence, and lack of randomized trials. CONCLUSION: This systematic review illustrates Level II-3 or Level III (limited) evidence for intrathecal infusion systems for long-term relief in chronic non-cancer pain.
Assuntos
Analgésicos/administração & dosagem , Bombas de Infusão Implantáveis/efeitos adversos , Injeções Espinhais/instrumentação , Dor/tratamento farmacológico , Analgésicos/uso terapêutico , Doença Crônica , Medicina Baseada em Evidências , Humanos , Injeções Espinhais/efeitos adversos , Injeções Espinhais/métodos , Dor/fisiopatologia , Medição da Dor/métodos , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: The evidence-based practice guidelines for the management of chronic spinal pain with interventional techniques were developed to provide recommendations to clinicians in the United States. OBJECTIVE: To develop evidence-based clinical practice guidelines for interventional techniques in the diagnosis and treatment of chronic spinal pain, utilizing all types of evidence and to apply an evidence-based approach, with broad representation by specialists from academic and clinical practices. DESIGN: Study design consisted of formulation of essentials of guidelines and a series of potential evidence linkages representing conclusions and statements about relationships between clinical interventions and outcomes. METHODS: The elements of the guideline preparation process included literature searches, literature synthesis, systematic review, consensus evaluation, open forum presentation, and blinded peer review. Methodologic quality evaluation criteria utilized included the Agency for Healthcare Research and Quality (AHRQ) criteria, Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria, and Cochrane review criteria. The designation of levels of evidence was from Level I (conclusive), Level II (strong), Level III (moderate), Level IV (limited), to Level V (indeterminate). RESULTS: Among the diagnostic interventions, the accuracy of facet joint nerve blocks is strong in the diagnosis of lumbar and cervical facet joint pain, whereas, it is moderate in the diagnosis of thoracic facet joint pain. The evidence is strong for lumbar discography, whereas, the evidence is limited for cervical and thoracic discography. The evidence for transforaminal epidural injections or selective nerve root blocks in the preoperative evaluation of patients with negative or inconclusive imaging studies is moderate. The evidence for diagnostic sacroiliac joint injections is moderate. The evidence for therapeutic lumbar intraarticular facet injections is moderate for short-term and long-term improvement, whereas, it is limited for cervical facet joint injections. The evidence for lumbar and cervical medial branch blocks is moderate. The evidence for medial branch neurotomy is moderate. The evidence for caudal epidural steroid injections is strong for short-term relief and moderate for long-term relief in managing chronic low back and radicular pain, and limited in managing pain of postlumbar laminectomy syndrome. The evidence for interlaminar epidural steroid injections is strong for short-term relief and limited for long-term relief in managing lumbar radiculopathy, whereas, for cervical radiculopathy the evidence is moderate. The evidence for transforaminal epidural steroid injections is strong for short-term and moderate for long-term improvement in managing lumbar nerve root pain, whereas, it is moderate for cervical nerve root pain and limited in managing pain secondary to lumbar post laminectomy syndrome and spinal stenosis. The evidence for percutaneous epidural adhesiolysis is strong. For spinal endoscopic adhesiolysis, the evidence is strong for short-term relief and moderate for long-term relief. For sacroiliac intraarticular injections, the evidence is moderate for short-term relief and limited for long-term relief. The evidence for radiofrequency neurotomy for sacroiliac joint pain is limited. The evidence for intradiscal electrothermal therapy is moderate in managing chronic discogenic low back pain, whereas for annuloplasty the evidence is limited. Among the various techniques utilized for percutaneous disc decompression, the evidence is moderate for short-term and limited for long-term relief for automated percutaneous lumbar discectomy, and percutaneous laser discectomy, whereas it is limited for nucleoplasty and for DeKompressor technology. For vertebral augmentation procedures, the evidence is moderate for both vertebroplasty and kyphoplasty. The evidence for spinal cord stimulation in failed back surgery syndrome and complex regional pain syndrome is strong for short-term relief and moderate for long-term relief. The evidence for implantable intrathecal infusion systems is strong for short-term relief and moderate for long-term relief. CONCLUSION: These guidelines include the evaluation of evidence for diagnostic and therapeutic procedures in managing chronic spinal pain and recommendations for managing spinal pain. However, these guidelines do not constitute inflexible treatment recommendations. These guidelines also do not represent a "standard of care."
Assuntos
Dor nas Costas/terapia , Medicina Baseada em Evidências , Dor nas Costas/epidemiologia , Dor nas Costas/etiologia , Doença Crônica , Humanos , Coluna Vertebral/efeitos dos fármacos , Coluna Vertebral/patologia , Coluna Vertebral/cirurgiaRESUMO
CONTEXT: Lower back pain is considered to be one of the most common complaints that brings a patient to a pain specialist. Several modalities in interventional pain management are known to be helpful to a patient with chronic low back pain. Proper diagnosis is required for appropriate intervention to provide optimal benefits. From simple trigger point injections for muscular pain to a highly complex intervention such as a spinal cord stimulator are very effective if chosen properly. The aim of this article is to provide the reader with a comprehensive reading for treatment of lower back pain using interventional modalities. EVIDENCE ACQUISITION: Extensive search for published literature was carried out online using PubMed, Cochrane database and Embase for the material used in this manuscript. This article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images were prepared by and belong to the author. RESULTS: This review article describes the most common modalities available to an interventional pain physician along with the most relevant current and past references for the treatment of lower back pain. All the graphics and images belong to the author. Although it is beyond the scope of this review article to include a very detailed description of each procedure along with complete references, a sincere attempt has been made to comprehensively cover this very complex and perplexing topic. CONCLUSION: Lower back pain is a major healthcare issue and this review article will help educate the pain practitioners about the current evidence based treatment options.
RESUMO
BACKGROUND: Intrathecal infusion systems are often used for patients with intractable pain when all else fails, including surgery. There is, however, some concern as to the effectiveness and safety of this treatment. STUDY DESIGN: A systematic review of intrathecal infusion systems for long-term management of chronic non-cancer pain. OBJECTIVE: To evaluate and update the effect of intrathecal infusion systems in managing chronic non-cancer pain. METHODS: The available literature on intrathecal infusion systems in managing chronic pain was reviewed. The quality assessment and clinical relevance criteria utilized were the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials and the Newcastle-Ottawa Scale criteria for observational studies. The level of evidence was classified as good, fair, and limited or poor based on the quality of evidence developed by the U.S. Preventative Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to December 2012, and manual searches of the bibliographies of known primary and review articles. OUTCOME MEASURES: The primary outcome measure was pain relief with short-term relief < 12 months and long-term relief ≥ 12 months. Secondary outcome measures were improvement in functional status, psychological status, return to work, and reduction in opioid intake. RESULTS: There were 28 studies identified for this systematic review. Of these, 21 were excluded from further review. A total of 7 non-randomized studies met inclusion criteria for methodological quality assessment. No randomized trials met the inclusion requirements.The evidence is limited based on observational studies. LIMITATIONS: The limitations of this systematic review include the paucity of literature. CONCLUSION: The evidence is limited for intrathecal infusion systems.
Assuntos
Anestésicos/administração & dosagem , Dor Crônica/terapia , Injeções Epidurais/métodos , Avaliação de Resultados em Cuidados de Saúde , Bases de Dados Factuais/estatística & dados numéricos , Humanos , Manejo da Dor , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos RetrospectivosRESUMO
OBJECTIVE: To develop evidence-based clinical practice guidelines for interventional techniques in the diagnosis and treatment of chronic spinal pain. METHODOLOGY: Systematic assessment of the literature. EVIDENCE: I. Lumbar Spine ⢠The evidence for accuracy of diagnostic selective nerve root blocks is limited; whereas for lumbar provocation discography, it is fair. ⢠The evidence for diagnostic lumbar facet joint nerve blocks and diagnostic sacroiliac intraarticular injections is good with 75% to 100% pain relief as criterion standard with controlled local anesthetic or placebo blocks. ⢠The evidence is good in managing disc herniation or radiculitis for caudal, interlaminar, and transforaminal epidural injections; fair for axial or discogenic pain without disc herniation, radiculitis or facet joint pain with caudal, and interlaminar epidural injections, and limited for transforaminal epidural injections; fair for spinal stenosis with caudal, interlaminar, and transforaminal epidural injections; and fair for post surgery syndrome with caudal epidural injections and limited with transforaminal epidural injections. ⢠The evidence for therapeutic facet joint interventions is good for conventional radiofrequency, limited for pulsed radiofrequency, fair to good for lumbar facet joint nerve blocks, and limited for intraarticular injections. ⢠For sacroiliac joint interventions, the evidence for cooled radiofrequency neurotomy is fair; limited for intraarticular injections and periarticular injections; and limited for both pulsed radiofrequency and conventional radiofrequency neurotomy. ⢠For lumbar percutaneous adhesiolysis, the evidence is fair in managing chronic low back and lower extremity pain secondary to post surgery syndrome and spinal stenosis. ⢠For intradiscal procedures, the evidence for intradiscal electrothermal therapy (IDET) and biaculoplasty is limited to fair and is limited for discTRODE. ⢠For percutaneous disc decompression, the evidence is limited for automated percutaneous lumbar discectomy (APLD), percutaneous lumbar laser disc decompression, and Dekompressor; and limited to fair for nucleoplasty for which the Centers for Medicare and Medicaid Services (CMS) has issued a noncoverage decision. II. Cervical Spine ⢠The evidence for cervical provocation discography is limited; whereas the evidence for diagnostic cervical facet joint nerve blocks is good with a criterion standard of 75% or greater relief with controlled diagnostic blocks. ⢠The evidence is good for cervical interlaminar epidural injections for cervical disc herniation or radiculitis; fair for axial or discogenic pain, spinal stenosis, and post cervical surgery syndrome. ⢠The evidence for therapeutic cervical facet joint interventions is fair for conventional cervical radiofrequency neurotomy and cervical medial branch blocks, and limited for cervical intraarticular injections. III. Thoracic Spine ⢠The evidence is limited for thoracic provocation discography and is good for diagnostic accuracy of thoracic facet joint nerve blocks with a criterion standard of at least 75% pain relief with controlled diagnostic blocks. ⢠The evidence is fair for thoracic epidural injections in managing thoracic pain. ⢠The evidence for therapeutic thoracic facet joint nerve blocks is fair, limited for radiofrequency neurotomy, and not available for thoracic intraarticular injections. IV. Implantables ⢠The evidence is fair for spinal cord stimulation (SCS) in managing patients with failed back surgery syndrome (FBSS) and limited for implantable intrathecal drug administration systems. V. ANTICOAGULATION ⢠There is good evidence for risk of thromboembolic phenomenon in patients with antithrombotic therapy if discontinued, spontaneous epidural hematomas with or without traumatic injury in patients with or without anticoagulant therapy to discontinue or normalize INR with warfarin therapy, and the lack of necessity of discontinuation of nonsteroidal anti-inflammatory drugs (NSAIDs), including low dose aspirin prior to performing interventional techniques. ⢠There is fair evidence with excessive bleeding, including epidural hematoma formation with interventional techniques when antithrombotic therapy is continued, the risk of higher thromboembolic phenomenon than epidural hematomas with discontinuation of antiplatelet therapy prior to interventional techniques and to continue phosphodiesterase inhibitors (dipyridamole, cilostazol, and Aggrenox). ⢠There is limited evidence to discontinue antiplatelet therapy with platelet aggregation inhibitors to avoid bleeding and epidural hematomas and/or to continue antiplatelet therapy (clopidogrel, ticlopidine, prasugrel) during interventional techniques to avoid cerebrovascular and cardiovascular thromboembolic fatalities. ⢠There is limited evidence in reference to newer antithrombotic agents dabigatran (Pradaxa) and rivaroxan (Xarelto) to discontinue to avoid bleeding and epidural hematomas and are continued during interventional techniques to avoid cerebrovascular and cardiovascular thromboembolic events. CONCLUSIONS: Evidence is fair to good for 62% of diagnostic and 52% of therapeutic interventions assessed. DISCLAIMER: The authors are solely responsible for the content of this article. No statement on this article should be construed as an official position of ASIPP. The guidelines do not represent "standard of care."
Assuntos
Dor Crônica/diagnóstico , Dor Crônica/terapia , Medicina Baseada em Evidências/normas , Guias como Assunto/normas , Manejo da Dor , Medula Espinal/patologia , Medicina Baseada em Evidências/métodos , Humanos , Manejo da Dor/instrumentação , Manejo da Dor/métodos , Manejo da Dor/normas , Estados UnidosRESUMO
BACKGROUND: Opioid abuse has continued to increase at an alarming rate since the 1990 s. As documented by different medical specialties, medical boards, advocacy groups, and the Drug Enforcement Administration, available evidence suggests a wide variance in chronic opioid therapy of 90 days or longer in chronic non-cancer pain. Part 1 describes evidence assessment. OBJECTIVES: The objectives of opioid guidelines as issued by the American Society of Interventional Pain Physicians (ASIPP) are to provide guidance for the use of opioids for the treatment of chronic non-cancer pain, to produce consistency in the application of an opioid philosophy among the many diverse groups involved, to improve the treatment of chronic non-cancer pain, and to reduce the incidence of abuse and drug diversion. The focus of these guidelines is to curtail the abuse of opioids without jeopardizing non-cancer pain management with opioids. RESULTS: 1) There is good evidence that non-medical use of opioids is extensive; one-third of chronic pain patients may not use prescribed opioids as prescribed or may abuse them, and illicit drug use is significantly higher in these patients. 2) There is good evidence that opioid prescriptions are increasing rapidly, as the majority of prescriptions are from non-pain physicians, many patients are on long-acting opioids, and many patients are provided with combinations of long-acting and short-acting opioids. 3) There is good evidence that the increased supply of opioids, use of high dose opioids, doctor shoppers, and patients with multiple comorbid factors contribute to the majority of the fatalities. 4) There is fair evidence that long-acting opioids and a combination of long-acting and short-acting opioids contribute to increasing fatalities and that even low-doses of 40 mg or 50 mg of daily morphine equivalent doses may be responsible for emergency room admissions with overdoses and deaths. 5) There is good evidence that approximately 60% of fatalities originate from opioids prescribed within the guidelines, with approximately 40% of fatalities occurring in 10% of drug abusers. 6) The short-term effectiveness of opioids is fair, whereas the long-term effectiveness of opioids is limited due to a lack of long-term (> 3 months) high quality studies, with fair evidence with no significant difference between long-acting and short-acting opioids. 7) Among the individual drugs, most opioids have fair evidence for short-term and limited evidence for long-term due to a lack of quality studies. 8) The evidence for the effectiveness and safety of chronic opioid therapy in the elderly for chronic non-cancer pain is fair for short-term and limited for long-term due to lack of high quality studies; limited in children and adolescents and patients with comorbid psychological disorders due to lack of quality studies; and the evidence is poor in pregnant women. 9) There is limited evidence for reliability and accuracy of screening tests for opioid abuse due to lack of high quality studies. 10) There is fair evidence to support the identification of patients who are non-compliant or abusing prescription drugs or illicit drugs through urine drug testing and prescription drug monitoring programs, both of which can reduce prescription drug abuse or doctor shopping. DISCLAIMER: The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."
Assuntos
Analgésicos Opioides/uso terapêutico , Dor Crônica/tratamento farmacológico , Transtornos Relacionados ao Uso de Opioides/prevenção & controle , Adolescente , Idoso , Criança , Feminino , Humanos , Lactente , Masculino , GravidezRESUMO
RESULTS: Part 2 of the guidelines on responsible opioid prescribing provides the following recommendations for initiating and maintaining chronic opioid therapy of 90 days or longer. 1. A) Comprehensive assessment and documentation is recommended before initiating opioid therapy, including documentation of comprehensive history, general medical condition, psychosocial history, psychiatric status, and substance use history. ( EVIDENCE: good) B) Despite limited evidence for reliability and accuracy, screening for opioid use is recommended, as it will identify opioid abusers and reduce opioid abuse. ( EVIDENCE: limited) C) Prescription monitoring programs must be implemented, as they provide data on patterns of prescription usage, reduce prescription drug abuse or doctor shopping. ( EVIDENCE: good to fair) D) Urine drug testing (UDT) must be implemented from initiation along with subsequent adherence monitoring to decrease prescription drug abuse or illicit drug use when patients are in chronic pain management therapy. ( EVIDENCE: good) 2. A) Establish appropriate physical diagnosis and psychological diagnosis if available prior to initiating opioid therapy. ( EVIDENCE: good) B) Caution must be exercised in ordering various imaging and other evaluations, interpretation and communication with the patient, to avoid increased fear, activity restriction, requests for increased opioids, and maladaptive behaviors. ( EVIDENCE: good) C) Stratify patients into one of the 3 risk categories - low, medium, or high risk. D) A pain management consultation, may assist non-pain physicians, if high-dose opioid therapy is utilized. ( EVIDENCE: fair) 3. Essential to establish medical necessity prior to initiation or maintenance of opioid therapy. ( EVIDENCE: good) 4. Establish treatment goals of opioid therapy with regard to pain relief and improvement in function. ( EVIDENCE: good) 5. A) Long-acting opioids in high doses are recommended only in specific circumstances with severe intractable pain that is not amenable to short-acting or moderate doses of long-acting opioids, as there is no significant difference between long-acting and short-acting opioids for their effectiveness or adverse effects. ( EVIDENCE: fair) B) The relative and absolute contraindications to opioid use in chronic non-cancer pain must be evaluated including respiratory instability, acute psychiatric instability, uncontrolled suicide risk, active or history of alcohol or substance abuse, confirmed allergy to opioid agents, coadministration of drugs capable of inducing life-limiting drug interaction, concomitant use of benzodiazepines, active diversion of controlled substances, and concomitant use of heavy doses of central nervous system depressants. ( EVIDENCE: fair to limited) 6. A robust agreement which is followed by all parties is essential in initiating and maintaining opioid therapy as such agreements reduce overuse, misuse, abuse, and diversion. ( EVIDENCE: fair) 7. A) Once medical necessity is established, opioid therapy may be initiated with low doses and short-acting drugs with appropriate monitoring to provide effective relief and avoid side effects. ( EVIDENCE: fair for short-term effectiveness, limited for long-term effectiveness) B) Up to 40 mg of morphine equivalent is considered as low dose, 41 to 90 mg of morphine equivalent as a moderate dose, and greater than 91 mg of morphine equivalence as high dose. ( EVIDENCE: fair) C) In reference to long-acting opioids, titration must be carried out with caution and overdose and misuse must be avoided. ( EVIDENCE: good) 8. A) Methadone is recommended for use in late stages after failure of other opioid therapy and only by clinicians with specific training in the risks and uses. ( EVIDENCE: limited) B) Monitoring recommendation for methadone prescription is that an electrocardiogram should be obtained prior to initiation, at 30 days and yearly thereafter. ( EVIDENCE: fair) 9. In order to reduce prescription drug abuse and doctor shopping, adherence monitoring by UDT and PMDPs provide evidence that is essential to the identification of those patients who are non-compliant or abusing prescription drugs or illicit drugs. ( EVIDENCE: fair) 10. Constipation must be closely monitored and a bowel regimen be initiated as soon as deemed necessary. ( EVIDENCE: good) 11. Chronic opioid therapy may be continued, with continuous adherence monitoring, in well-selected populations, in conjunction with or after failure of other modalities of treatments with improvement in physical and functional status and minimal adverse effects. ( EVIDENCE: fair). DISCLAIMER: The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."
Assuntos
Analgésicos Opioides/uso terapêutico , Dor Crônica/tratamento farmacológico , Transtornos Relacionados ao Uso de Opioides/prevenção & controle , Adolescente , Idoso , Criança , Feminino , Humanos , Lactente , Masculino , GravidezRESUMO
Opioid-induced hyperalgesia (OIH) is defined as a state of nociceptive sensitization caused by exposure to opioids. The condition is characterized by a paradoxical response whereby a patient receiving opioids for the treatment of pain could actually become more sensitive to certain painful stimuli. The type of pain experienced might be the same as the underlying pain or might be different from the original underlying pain. OIH appears to be a distinct, definable, and characteristic phenomenon that could explain loss of opioid efficacy in some patients. Findings of the clinical prevalence of OIH are not available. However, several observational, cross-sectional, and prospective controlled trials have examined the expression and potential clinical significance of OIH in humans. Most studies have been conducted using several distinct cohorts and methodologies utilizing former opioid addicts on methadone maintenance therapy, perioperative exposure to opioids in patients undergoing surgery, and healthy human volunteers after acute opioid exposure using human experimental pain testing. The precise molecular mechanism of OIH, while not yet understood, varies substantially in the basic science literature, as well as clinical medicine. It is generally thought to result from neuroplastic changes in the peripheral and central nervous system (CNS) that lead to sensitization of pronociceptive pathways. While there are many proposed mechanisms for OIH, 5 mechanisms involving the central glutaminergic system, spinal dynorphins, descending facilitation, genetic mechanisms, and decreased reuptake and enhanced nociceptive response have been described as the important mechanisms. Of these, the central glutaminergic system is considered the most common possibility. Another is the hypothesis that N-methyl-D-aspartate (NMDA) receptors in OIH include activation, inhibition of the glutamate transporter system, facilitation of calcium regulated intracellular protein kinase C, and cross talk of neural mechanisms of pain and tolerance. Clinicians should suspect OIH when opioid treatment's effect seems to wane in the absence of disease progression, particularly if found in the context of unexplained pain reports or diffuse allodynia unassociated with the original pain, and increased levels of pain with increasing dosages. The treatment involves reducing the opioid dosage, tapering them off, or supplementation with NMDA receptor modulators. This comprehensive review addresses terminology and definition, prevalence, the evidence for mechanism and physiology with analysis of various factors leading to OIH, and effective strategies for preventing, reversing, or managing OIH.
Assuntos
Analgésicos Opioides/efeitos adversos , Hiperalgesia/induzido quimicamente , Doença Crônica , Humanos , Hiperalgesia/epidemiologia , Dor/tratamento farmacológico , PrevalênciaRESUMO
BACKGROUND: Intrathecal drug infusion therapy is usually considered when spinal-acting analgesics or antispasmodics administered via the oral or transdermal routes fail to control patients' pain or are associated with unacceptable side effects. The intrathecal administration of centrally acting agents bypasses the blood-brain-barrier resulting in much higher cerebrospinal fluid (CSF) concentrations while using reduced amounts of medication to achieve equipotent doses. The intrathecal approach is associated with higher rates of satisfactory pain relief and lower rates of treatment failures and technical complications compared to the epidural route. A paucity of randomized controlled trials (RCTs) has led to concern regarding proper use, selection criteria, and safety of these devices. Cost effectiveness and comparative therapies have now also become a focus of discussion. OBJECTIVE: The purpose of this systematic review is to evaluate and update the available evidence for the efficacy and safety of intrathecal infusions used in long-term management (> 6 months) of chronic pain. This paper will not focus on intrathecal administration for spasticity or movement disorders. STUDY DESIGN: A systematic review of intrathecal infusion through implanted drug delivery devices for chronic pain. METHODS: Literature search through EMBASE, Medline, Cochrane databases, and systematic reviews as well as peer-reviewed non-indexed journals from 1980 to December 2010. Studies are assessed using the Agency for Healthcare Research and Quality (AHRQ) criteria for observational studies and the Cochrane Musculoskeletal Review Group criteria for randomized trials. The level of evidence was determined using 5 levels of evidence, ranging from Level I to III with 3 subcategories in Level II, based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). OUTCOME MEASURES: The primary outcome measure for chronic non-cancer is pain relief (short-term relief ≤ one-year and long-term > one-year), whereas it is 3 months for cancer. Secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake. RESULTS: The level of evidence for this systematic review of non-cancer pain studies meeting the inclusion criteria of continuous use of an intrathecal drug delivery system (IDDS) for at least 12 months duration with at least 25 patients in the cohort, is Level II-3 based on USPSTF criteria. The level of evidence for this systemic review for cancer-related pain studies meeting the inclusion criteria of continuous use of IDDS for at least 3 months duration with at least 25 patients in the cohort is Level II-2 based on USPSTF criteria. CONCLUSION: Based on the available evidence, the recommendation for intrathecal infusion systems for cancer-related pain is moderate recommendation based on the high quality of evidence and the recommendation is limited to moderate based on the moderate quality of evidence from non-randomized studies for non-cancer related pain.