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Jeffrey T Loh,1 Andrea L Nicol,1 David Elashoff,2 F Michael Ferrante,1 1Department of Anesthesiology, David Geffen School of Medicine, 2Department of Biomathematics, University of California Los Angeles, Los Angeles, CA, USA Background: Many studies have assessed the efficacy of radiofrequency ablation to denervate the facet joint as an interventional means of treating axial low-back pain. In these studies, varying procedural techniques were utilized to ablate the nerves that innervate the facet joints. To date, no comparison studies have been performed to suggest superiority of one technique or even compare the prevalence of side effects and complications. Materials and methods: A retrospective chart review was performed on patients who underwent a lumbar facet denervation procedure. Each patient's chart was analyzed for treatment technique (early versus advanced Australian), preprocedural visual numeric scale (VNS) score, postprocedural VNS score, duration of pain relief, and complications. Results: Pre- and postprocedural VNS scores and change in VNS score between the two groups showed no significant differences. Patient-reported benefit and duration of relief was greater in the advanced Australian technique group (P=0.012 and 0.022, respectively). The advanced Australian technique group demonstrated a significantly greater median duration of relief (4 months versus 1.5 months, P=0.022). Male sex and no pain-medication use at baseline were associated with decreased postablation VNS scores, while increasing age and higher preablation VNS scores were associated with increased postablation VNS scores. Despite increasing age being associated with increased postablation VNS scores, age and the advanced Australian technique were found to confer greater patient self-reported treatment benefit. Conclusion: The advanced Australian technique provides a significant benefit over the early Australian technique for the treatment of lumbar facet pain, both in magnitude and duration of pain relief. Keywords: low-back pain, lumbar facet arthropathy, interventional pain management, radiofrequency ablation

Background and Objectives: Multiple processes have been identified as potential contributors to chronic pain, with increasing evidence illustrating an association with aberrant levels of neuroimmune mediators. The primary objectives of the present study were to examine central nervous system cytokines, chemokines, and growth factors present in a chronic pain population and to explore patterns of the same mediator molecules over time. Secondary objectives explored the relationship of central and peripheral neuroimmune mediators while examining the levels of anxiety, depression, sleep quality, and perception of pain associated with the chronic pain patient experience., Methods: Cerebrospinal fluid (CSF) from a population of majority postlaminectomy syndrome patients (N = 8) was compared with control CSF samples (N = 30) to assess for significant differences in 10 cytokines, chemokines, and growth factors. The patient population was then followed over time, analyzing CSF, plasma, and psychobehavioral measures., Results: The present observational study is the first to demonstrate increased mean CSF levels of interleukin-8 (IL-8; P < 0.001) in a small population of majority postlaminectomy syndrome patients, as compared with a control population. Over time in pain patients, CSF levels of IL-8 increased significantly (P < 0.001)., Conclusions: These data indicate that IL-8 should be further investigated and psychobehavioral components considered in the overall chronic pain paradigm. Future studies examining the interactions between these factors and IL-8 may identify novel targets for treatment of persistent pain states.

Background: Chronic postherniorrhaphy inguinal pain (CPIP) is a complex, major health problem. In the absence of recurrence or meshoma, laparoscopic retroperitoneal triple neurectomy (LRTN) has emerged as an effective surgical treatment of CPIP., Methods: This prospective pilot study evaluated the neurophysiological and clinical effects of LRTN. Ten consecutive adult CPIP patients with unilateral predominantly neuropathic inguinodynia underwent three comprehensive quantitative sensory testing (QST) assessments (preoperative, immediate postoperative, and late postoperative). Pain severity, health-related function, and sleep quality were assessed over the course of a 6-month follow-up period., Results: QST revealed marked increases in mechanical, pressure, thermal, and pain thresholds in the areas with maximum pain prior to LRTN surgery for the immediate (P < 0.01; mean 160.9 minutes, range 103 to 255 minutes after extubation) and late postoperative (P < 0.05; mean 27.9 days, range 14 to 78 days after surgery) assessments compared to baseline. Wind-up phenomena were eliminated postoperatively. LRTN provided robust group-level improvements of all clinical measures. No preoperative QST variables were found to be predictive of surgical outcomes. The positive change in heat pain threshold (preoperative compared to late postoperative) showed significant positive correlations with improvements of pain scores and function., Conclusions: LRTN may produce immediate, profound, and consistent positive effects across multiple mechanical, pressure, and thermal QST variables, and marked improvements of clinical outcomes in selected CPIP patients. These data contribute to the understanding of mechanisms involved in the success of LRTN. Large, high-powered studies are warranted to determine whether preoperative or repeated longitudinal QST may guide patient selection and predict effectiveness of LRTN., (© 2016 World Institute of Pain.)

Background: Mechanical chest wall pain is a common presenting complaint in the primary care office, emergency room, and specialty clinic. Diagnostic testing is often expensive due to similar presenting symptoms that may involve the heart or lungs. Since the chest wall biomechanics are poorly understood by many clinicians, few effective treatments are offered to patients with rib-related acute pain, which may lead to chronic pain., Objective: This case series and literature review illustrates biomechanics involved in the pathogenesis of rib-related chest wall pain and suggests an effective multi-modal treatment plan using interventional techniques with emphasis on manual manipulative techniques., Study Design: Case series and literature review., Setting: Pain clinic in an academic medical center., Results: This is a case series of 3 patients diagnosed with painful rib syndrome using osteopathic palpatory physical examination techniques. Ultrasound-guided intercostal nerve blocks were followed by manual manipulation of mechanically displaced ribs as a part of our multi-modal treatment plan. A review of the literature was undertaken to clarify nomenclature used in the description of rib-related pain, to describe the biomechanics involved in the pathogenesis of mechanical rib pain, and to illustrate the use of effective manual manipulation techniques., Limitation: This review is introductory and not a complete review of all manual or interventional pain management techniques applicable to the treatment of mechanical rib-related pain., Conclusions: Manual diagnostic and therapeutic skills can be learned by physicians to treat biomechanically complex rib-related chest wall pain in combination with interventional image-guided techniques. Pain physicians should learn certain basic manual manipulation skills both for diagnostic and therapeutic purposes.

Background and Objectives: This study attempts to assess the intensity and quality of pain and health-related quality of life in patients with sacroiliac syndrome and to compare those constructs to patients with lumbar radiculopathy.Methods: A retrospective review of patient records with the diagnosis of sacroiliac syndrome or lumbar radiculopathy was performed. Patients with sacroiliac syndrome were age and gender matched to patients with lumbar radiculopathy. Data from the McGill Pain Questionnaire, visual numerical pain scores, and SF-36 health-related quality of life measure (version 2) were compared between groups.Results: The age of patients with a traumatic etiology for sacroiliac syndrome was lower than those with previous back surgery and "idiopathic" etiologies (P < .02). Duration of pain in patients with "idiopathic" etiology was longer in comparison to those with previous back surgery (P < .005). No statistical difference occurred between patients with sacroiliac syndrome and lumbar radiculopathy with respect to McGill pain scores, visual numerical pain scores, and SF-36 health-related quality of life measure.Conclusions: The results of this study suggest the following: (1) no true difference exists in the health-related quality of life or pain scores/descriptors between patients with SI syndrome or lumbar radiculopathy, or (2) the presence of comorbid spinal conditions confounds the ability of the SF-36 to detect disparities in health-related quality of life among differing etiologies of low-back pain, despite the use of rigorous diagnostic criteria, and/or (3) other factors besides the diagnostic categories of low-back pain (e.g., functional capability, psychological stress) may be primary determinants of health-related quality of life. To our knowledge, no other study has attempted to use the SF-36 to detect differences in health-related quality of life among patients with different spinal diagnoses. [ABSTRACT FROM AUTHOR]

Introduction: Spinal and non-spinal pathologies can cause low back pain. Non-spinal sources of low back pain include the sacroiliac joint (SIJ) and the hip. SIJ pain can be treated either conservatively or surgically. Current strategies for managing sacroiliac joint pain are debated, and limited evidence exists. Areas covered: The present expert opinion updates current evidence on conservative and surgical modalities for SIJ pain Expert opinion: Surgical management for SIJ pain is effective. However, it exposes patients to surgery and, therefore, related complications. Conservative management may be implemented in patients with moderate SIJ pain, with less than six months of symptoms, or not eligible for surgery. Several noninvasive modalities are available, mostly centered on intra-articular injections. Corticosteroids, platelet-rich plasma, and stem cells have only midterm lasting effects, at most for nine months. Radiofrequency ablation is another methodology for pain relief. Both continuous and pulsatile radiofrequency ablation are associated with good outcomes. SIJ fusion can be performed using different techniques; however, a clear recommendation on the most appropriate modality for the management of SIJ pain is still debated. [ABSTRACT FROM AUTHOR]

Study Design: Systematic review of the literature and subsequent meta-analysis for the development of a new guideline. Objectives: This manuscript summarizes the recommendations from a new clinical guideline published by the German Spine Society. It covers the current evidence on recommendations regarding the indication, test blocks and use of radiofrequency denervation. The guidelines aim is to improve patient care and efficiency of the procedure. Methods: A multidisciplinary working group formulated recommendations based on the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) approach and the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument. Results: 20 clinical questions were defined for guideline development, with 87.5% consensus achieved by committee members for one recommendation and 100% consensus for all other topics. Specific questions that were addressed included clinical history, examination and imaging, conservative treatment before injections, diagnostic blocks, the injected medications, the cut-off value in pain-reduction for a diagnostic block as well as the number of blocks, image guidance, the cannula trajectories, the lesion size, stimulation, repeat radiofrequency denervation, sedation, cessation or continuation of anticoagulants, the influence of metal hardware, and ways to mitigate complications. Conclusion: Radiofrequency (RF) denervation of the spine and the SI joint may provide benefit to well-selected individuals. The recommendations of this guideline are based on very low to moderate quality of evidence as well as professional consensus. The guideline working groups recommend that research efforts in relation to all aspects of management of facet joint pain and SI joint pain should be intensified. [ABSTRACT FROM AUTHOR]

Background: Epidural anesthesia is commonly utilized for pain management following lower abdominal surgeries; however, the search for an optimal analgesic additive continues. Objectives: This study aimed to compare the efficacy of epidural dexamethasone versus epidural morphine (EM) in managing postoperative pain after total abdominal hysterectomy. Methods: This randomized controlled trial enrolled patients undergoing total abdominal hysterectomy (TBAH) and assigned them to two groups: Group D (Dexamethasone), which received epidural dexamethasone (8 mg) with bupivacaine, and Group M (Morphine), which received epidural morphine (10 mg) with bupivacaine. Marcaine (bupivacaine) 0.25% was used in both groups. Baseline characteristics, surgical outcomes, physiological parameters, pain management, adverse effects, and blood sugar levels were analyzed and compared between the groups. Results: The groups exhibited similar initial characteristics and surgical outcomes. Vital signs, including heart rate (HR), mean arterial pressure, respiratory rate, and oxygen saturation, remained consistent before and after surgery. The Dexamethasone group (Group D) demonstrated superior pain control compared to the Morphine group (Group M). Patients in Group D required pain medication for a significantly shorter duration (24 hours vs. 36 hours, P < 0.05), representing a 50% reduction in medication duration. Additionally, Group D patients required fewer rescue analgesics (1.2 doses vs. 2.1 doses, P < 0.05), indicating a 43% decrease in the need for additional medication. The time to a visual analog scale (VAS) score exceeding 4 was significantly longer in Group D, indicating less intense pain for an extended period. Although no significant differences were observed in common postoperative side effects, Group D exhibited a lower incidence of these effects, albeit not statistically significant. Furthermore, Group D showed a significantly lower incidence of hyperglycemia at the 8th hour post-surgery compared to Group M (P < 0.05), suggesting a potential benefit of epidural dexamethasone in mitigating hyperglycemia risk. Conclusions: Epidural dexamethasone appears to offer superior analgesic efficacy compared to epidural morphine in postoperative pain management after total abdominal hysterectomy. The findings suggest that Group D (Dexamethasone) experienced improved pain management, reduced medication requirements, and a lower incidence of hyperglycemia. Further research with larger cohorts and extended follow-up is warranted to validate these findings and guide clinical practice. [ABSTRACT FROM AUTHOR]

Background: Myofascial pain syndrome is a regional condition of muscle pain and stiffness and is classically characterized by the presence of trigger points in affected musculature. Botulinum toxin type A (BoNT-A) has been shown to have antinociceptive properties and elicit sustained muscle relaxation, thereby possibly affording even greater relief than traditional strategies. Our goal was to determine whether direct injection of BoNT-A into painful muscle groups is effective for cervical and shoulder girdle myofascial pain., Methods: An enriched protocol design was used, wherein 114 patients with cervical and shoulder girdle myofascial pain underwent injection of BoNT-A to determine their response to the drug. Fifty-four responders were then enrolled in a 12-week, randomized, double-blind, placebo-controlled trial. Pain scales and quality of life measures were assessed at baseline and at routine follow-up visits until completion of the study after 26 weeks., Results: Injection of BoNT-A into painful muscle groups improved average visual numerical pain scores in subjects who received a second dose of BoNT-A compared to placebo (P = 0.019 [0.26, 2.78]). Subjects who received a second dose of BoNT-A had a reduced number of headaches per week (P = 0.04 [0.07, 4.55]). Brief Pain Inventory interference scores for general activity and sleep were improved (P = 0.046 [0.038, 3.700] and 0.02 [0.37, 4.33], respectively) in those who received a second dose of BoNT-A., Conclusion: BoNT-A injected directly into painful muscle groups improves average pain scores and certain aspects of quality of life in patients experiencing severe cervical and shoulder girdle myofascial pain.

Objective: The authors recently determined that early and longer term mortality after initiation or reinitiation of intrathecal opioid therapy is higher than previously appreciated: 0.088% within 3 days, 0.39% at 1 month, and 3.89% at 1 year. These rates were 7.5 (confidence interval, 5.7-9.8), 3.4 (confidence interval, 2.9-3.8), and 2.7 (confidence interval, 2.6-2.8) times higher, respectively, at each interval than expected based on the age- and gender-matched general U.S. population. A substantial portion of this excess mortality is probably therapy related and cannot be entirely accounted for by underlying demographic or patient-related factors, or by device malfunctions. We also analyzed multiple complementary internal, governmental, and insurance databases to quantify mortality and to identify medical practice patterns that appear to be associated with patient mortality risks, and to suggest measures for physicians and health care facilities to consider in order to reduce those risks. Both of those objectives involve judgments, which may be controversial and are subject to practical limitations., Results: Multiple clinical and patient- or therapy-related factors appear to increase the risk for early post-implant mortality. Specific risk mitigation measures associated with each factor include: close attention to the starting intrathecal opioid dose (or restarting dose after therapy interruption); avoidance of outpatient implant or other device procedures that involve less than 24-hour monitoring for respiratory depression; supervision of concomitant opioid, respiratory depressant, or other central nervous system active drug intake early post-implant and chronically in the outpatient setting; and careful programming or dosage calculations and decisions in order to avoid the unintentional administration of high intrathecal opioid drug doses., Conclusions: Mortality after initiation of or device interventions in intrathecal drug delivery patients appears to occur as a result of multiple factors that present possible mitigation opportunities for physicians and health care facilities.

Background and Objectives: : Subdural injection is a well-known but often poorly recognized complication of neuraxial anesthesia/analgesia. This report aims to further describe the clinical presentation of subdural injection by analyzing radiographically proven cases. A new diagnostic algorithm is then proposed., Methods: : A literature search identified 70 radiographically confirmed cases of subdural injection. The prevalence of numerous presenting characteristics and their relationship to the volume of injected local anesthetics were examined. The ability of 2 previously published diagnostic paradigms to detect proven subdural injection was compared with that of a newly proposed algorithm., Results: : The dermatomal distribution of sensory blockade was excessive in 74% of cases, restricted in 17%, and neither in 9%. Motor blockade and respiratory depression were associated with larger local anesthetic injection volumes (median volume = 14 vs. 8 mL [P <.009] and 15 vs. 10 mL [P <.035], respectively), but segmental spread and cardiovascular depression were not. Only 33% of cases were positive for 2 or more of Collier's criteria; Lubenow et al.'s diagnostic paradigm detected 71% of cases. We propose a diagnostic algorithm structured as a "roadmap," whereby the clinician inputs the assumed neuraxial block (epidural vs. subarachnoid), and distribution of sensory blockade (excessive, restricted, neither). Specific minor criteria are then applied to diagnose subdural injections. This algorithm detected 93% of subdurals with excessive sensory block distribution, and all of those with restricted and normal distribution., Conclusions: : Radiographically proven subdural injections were used to further define the clinical presentation of subdural analgesia/analgesia and a new diagnostic algorithm is proposed.

Myofascial pain syndrome, which has trigger points, is one of the most common causes of acute and chronic musculoskeletal pain. The trigger points formed by damage to the muscle fibers are focal areas of taut bands in the skeletal muscle that are hypersensitive to palpation. When manual pressure is applied over a trigger point, it produces distinct local and referred pain. Although various modalities have been used to treat trigger points, trigger point injection is the most effective treatment modality to inactivate trigger points. This article reviews the diagnosis and treatment of myofascial pain syndrome and the technique of trigger point injection. [ABSTRACT FROM AUTHOR]

Background and Objectives: Implanted delivery systems for intrathecal drug administration have become more commonplace in the management of refractory cancer and nonmalignant pain. Complications may be related to drug side effects or to technical problems possibly involving the pump and/or catheter. The occurrence of postimplantation, new onset, lumbar radicular pain warrants careful clinical and radiographic examination. We suggest a paradigm for imaging of potential intervertebral foraminal catheter migration., Case Report: New onset, intractable, lumbar radicular pain occurred 3 months after implantation of a one-piece catheter into the lumbar cistern. Magnetic resonance imaging of the lumbar spine showed no granuloma but rather a contrast-enhancing lesion at the right L4-L5 intervertebral foramen. Subsequent computed tomography revealed migration of the catheter into the intervertebral foramen. Surgical repositioning of the catheter resulted in resolution of the symptoms., Conclusion: Patients with implanted drug delivery systems with positioning of the catheter tip into the lumbar cistern may develop new onset lumbar radicular pain as a result of catheter migration into an intervertebral foramen. Magnetic resonance imaging (MRI) is suggested as the initial imaging study to survey the spine and to evaluate for granuloma formation. Reimaging with computed tomography is essential to follow the course of the catheter and to delineate distal catheter tip location. It is suggested that positioning of the distal catheter tip at a location midway between the superior and inferior articular surfaces of the facet joint may minimize this complication.

Objective: Dejerine-Roussy syndrome is a complex of various signs and symptoms in patients suffering from central thalamic pain, usually secondary to a vascular etiology. We describe a patient presenting with the potentially devastating signs and symptoms of thalamic stroke, at least temporally related to spinal cord stimulator implantation. The etiology of the patient's affliction was subsequently revealed to be a conversion disorder. Case report A 37-year-old woman presented for spinal cord stimulation as treatment of her brachial plexopathy after failure of conservative therapy. Before implantation, she underwent a clinical interview with a psychologist and psychometric testing. No psychological pathology was detected. Trial and permanent implantation of the cervical stimulator lead and pulse generator were uneventful. Eleven days after receiving the permanent implant, the patient experienced right-sided hemicorporal numbness and burning dysesthesia. The patient was admitted, and a diagnosis of Dejerine-Roussy syndrome (thalamic stroke) was made. She was discharged, and her symptomatology waxed and waned over a period of weeks. The patient was subsequently admitted for psychiatric evaluation because of anxiety attacks. During her protracted admission, her psychiatrists strongly suspected a conversion disorder. The stimulator was removed, and the patient received supportive care only. Within 6 months, sensory symptoms and all motor deficits had completely resolved., Conclusions: Despite careful preoperative evaluation, latent psychosocial issues may limit the effectiveness of spinal cord stimulation. We present a case of conversion disorder masquerading as Dejerine-Roussy syndrome after spinal cord stimulation. The implications of the failure of preoperative psychological evaluation and screening to avert implantation are discussed.

Objective. This article presents an overview of the use of intrathecal bupivacaine (with and without opioid), focusing on laboratory data and clinical use for chronic pain. Some background on epidural use is included to support the intrathecal literature. Materials and Methods. Currently available literature (MEDLINE) regarding the use of intrathecal bupivacaine is reviewed. Prior to presenting the intrathecal bupivacaine data, an overview of data related to bupivacaine stability, microbiology, preclinical toxicology, and pharmacokinetics is presented, along with a brief review of the epidural bupivacaine literature. Results. Based on the current available literature, intrathecal bupivacaine appears to be a safe and acceptable method of treatment for chronic pain in both cancer and noncancer patients. The stability and bacteriologic studies support the use of bupivacaine in external or implantable drug administration devices. Toxicity studies in laboratory animals suggest complications only at plasma levels that would not be seen at clinically relevant doses of intrathecal administration. Bupivacaine is a clinically effective addition to intrathecal opioids. Bupivacaine administration is more effective intrathecally, providing better pain relief than epidural administration. Reports of complications are infrequent. Further studies are needed to define the use of intrathecal bupivacaine and should include long-term safety. Compatibility studies will also be needed when bupivacaine is used in combination with other agents. In addition, outcome studies are needed specifically to differentiate use of intrathecal bupivacaine based on the source and mechanism of pain. Conclusions. While there are few long-term randomized prospective studies at this point, we conclude that intrathecal bupivacaine appears to be a safe and efficacious treatment in both cancer and noncancer pain.

Background and Objectives: Radiofrequency (RF) denervation of the sacroiliac (SI) joint has been advocated for the treatment of sacroiliac syndrome, yet no clinical studies or case series support its use., Methods: We report the results of a consecutive series of 50 SI joint RF denervations performed in 33 patients with sacroiliac syndrome. All patients underwent diagnostic SI joint injections with local anesthetic before denervation. Changes in visual analog pain scores (VAS), pain diagrams, physical examination (palpation tenderness over the joint, myofascial trigger points overlying the joint, SI joint pain provocation tests, and range of motion of the lumbar spine), and opioid use were assessed pre- and postdenervation., Results: The criteria for successful RF denervation were at least a 50% decrease in VAS for a period of at least 6 months; 36.4% of patients (12 of 33) met these criteria. Failure of denervation correlated with the presence of disability determination and pain on lateral flexion to the affected side. The average duration of pain relief was 12.0 +/- 1.2 months in responders versus 0.9 +/- 0.2 months in nonresponders (P < or = 0.0001). A positive response was associated with an atraumatic inciting event. Successful denervation was associated with a change in the pain diagram and a reduction in the pattern of referred pain, a normalization of SI joint pain provocation tests, and a reduction in the use of opioids., Conclusions: This study suggests that RF denervation of the SI joint can significantly reduce pain in selected patients with sacroiliac syndrome for a protracted time period. Moreover, certain abnormal physical findings (i.e., SI joint pain provocation tests) revert to normal for the duration of the analgesia.

Evidence-based medicine depends on the existence of controlled clinical trials that establish the safety and efficacy of specific therapeutic techniques. Many interventions in clinical practice have achieved widespread acceptance despite little evidence to support them in the scientific literature; the critical appraisal of these interventions based on accumulating experience is a goal of medicine. To clarify the current state of knowledge concerning the use of various drugs for intraspinal infusion in pain management, an expert panel conducted a thorough review of the published literature. The exhaustive review included 5 different groups of compounds, with morphine and bupivacaine yielding the most citations in the literature. The need for additional large published controlled studies was highlighted by this review, especially for promising agents that have been shown to be safe and efficacious in recent clinical studies.

Consensus guidelines developed by an expert panel are helpful to clinicians when there is variation in practice and lack of a firm evidence base for an intervention, such as intraspinal therapy for pain. An internet-based survey of practitioners revealed remarkable variation in practice patterns surrounding intraspinal therapy. This prompted an interdisciplinary panel with extensive clinical experience in intraspinal infusion therapy to evaluate the results of the survey, the systematic reviews of the literature pertaining to this approach, and their own clinical experience with long-term spinal infusions. The panel proposed a scheme for the selection of drugs and doses for intraspinal therapy, and suggested guidelines for administration that would increase the likelihood of a successful outcome. These expert panel guidelines were designed to provide an initial structure for clinical decision making that is based on the best available evidence and the perspectives of experienced clinicians.

Purpose: In labour, neuraxial analgesia is the standard in the provision of pain relief. However, the optimal mode of delivering epidural solution has not been determined, and some parturients may need an alternative to epidural analgesia. We sought to conduct a systematic review and network meta-analysis to compare continuous epidural infusion (CEI), programmed intermittent epidural bolus (PIEB), computer-integrated CEI, computer-integrated PIEB, patient-controlled epidural bolus (PCEA), fentanyl patient-controlled analgesia (PCA), and remifentanil PCA, either alone or in combination., Methods: We searched CENTRAL, CINAHL, Ovid Embase, Ovid Medline, and Web of Science for randomized controlled trials that included nulliparous and/or multiparous parturients in spontaneous or induced labour. The maintenance epidural solution had to include a low concentration local anesthetic and an opioid. Specific subgroups in the obstetric population such as preeclampsia were excluded. Network meta-analysis was performed with a frequentist method, and continuous and dichotomous outcomes are presented as mean differences and odds ratios, respectively, with 95% confidence intervals., Results: Overall, 73 trials were included. For the first coprimary outcome, the need for rescue analgesia, CEI was inferior to PIEB and PIEB + PCEA was superior to PCEA alone, with a low certainty of evidence given the presence of serious limitations and imprecision. The second coprimary outcome, the maternal satisfaction, was improved by PIEB + PCEA compared with CEI + PCEA and PCEA alone, with a low quality of evidence in view of the presence of serious limitations and imprecision. Fentanyl PCA increased the requirement for rescue analgesia and decreased maternal satisfaction relative to many methods of delivering epidural solution. In terms of secondary outcomes, PIEB increased analgesic efficacy compared with CEI, and PCEA reduced local anesthetic consumption at the expense of inferior analgesia relative to CEI and PIEB. PIEB + PCEA was superior to CEI + PCEA in regard to the pain score at 2 h and 4 h, consumption of local anesthetic, incidence of lower lower limb motor blockade and the rate of spontaneous vaginal delivery. Fentanyl and remifentanil PCA did not provide the same level of analgesia as all epidural methods, resulted in increasing analgesic ineffectiveness with time spent in labour, and predisposed to a higher incidence of side effects such as nausea and/or vomiting and sedation. Remifentanil PCA was superior to fentanyl PCA for analgesia at an early time point, and it increased the incidence of oxygen desaturation relative to other strategies of delivering epidural solution., Conclusions: Opioid PCA did not provide the same level of analgesia as epidural methods with a higher incidence of side effects. We interpret the findings of our systematic review and network meta-analysis as suggesting PIEB + PCEA to be the optimal delivery mode of epidural solution. Nevertheless, the potential differing importance of the various maternal, fetal, and neonatal outcomes in determining which is optimal has not, to our knowledge, been elucidated yet., Study Registration: PROSPERO (CRD42021254978); registered 27 May 2021., (© 2023. Canadian Anesthesiologists' Society.)

Subarachnoid neurolysis using ethanol to destroy selectively the posterior roots of the spinal cord is a method for providing pain relief in patients with advanced cancer. Weakness of the extremities is a complication of the procedure that has been attributed to spread of the neurolytic agent to the anterior roots. The authors provide evidence of spinal cord injury as a cause of lower extremity weakness in a patient after subarachnoid ethanol neurolysis.

Background and Objectives: 2-Chloroprocaine is rapidly metabolized in the blood to yield 2-chloro-para-aminobenzoic acid (an inactive metabolite) and diethylaminoethanol (DEAE). DEAE possesses local anesthetic activity. The only reported assay for DEAE is a colorimetric method., Methods: Clinical samples of whole blood and serum were obtained from patients receiving stepped intravenous infusions of 3% 2-chloroprocaine. A high pH-dependent liquid-liquid extraction step with diethyl ether was used to eliminate interfering peaks in high-pressure liquid chromatography (HPLC) analysis. Separation and quantitation were performed using HPLC on a polymeric-reversed phase column with a mobile phase consisting of 10% or 20% acetonitrile (for whole blood or serum analysis, respectively) in 50 mm aqueous sodium phosphate buffer, pH = 11.50. The elution order of DEAE and its analogues was tested to interpret the HPLC separation mechanism., Results: Extraction recovery of DEAE from whole blood was 67 +/- 13.5%, from serum, 71 +/- 12.2%, and from water, 75 +/- 2.9%. The high pH value of the mobile phase resulted in sharp, well-resolved peaks with run times of approximately 8 minutes using 20% acetonitrile. The lower limit of detection was 5 ng/mL of DEAE from a 1-mL sample. The elution order of DEAE and its analogues indicated that separation was based on the hydrophobicity of the analytes rather than polar group interactions occurring with silica-based stationary phase., Conclusions: A new, simple and rapid HPLC method for extraction and measurement of DEAE in whole blood or serum samples is reported here.

Pain due to malignancy can be controlled through simple means in most patients. In certain refractory cases, however, the chronic delivery of analgesics to the epidural or subarachnoid space may be appropriate. This review will discuss criteria for patient selection for neuraxial drug delivery, the technologic systems available for neuraxial drug delivery, and criteria for selection of the appropriate technology in the individual patient.

Objectives: To describe the extent of pain relief two weeks after an epidural steroid injection in patients with herniated disks and lumbar spinal stenosis, and to identify predictors of changes in pain ratings in each population., Methods: The study design was a prospective evaluation of patients with lumbar spinal stenosis (LSS) and herniated disks (HDs) referred to a hospital-based pain clinic for an epidural steroid injection (ESI). A complete history, detailed physical examination, comprehensive pain questionnaire, and Brief Symptom Inventory were obtained for all patients. Pain was assessed at baseline and two weeks following a single ESI using a visual analog scale., Results: Two hundred twelve patients (mean age 54 years) were enrolled, and 78 of these provided pain ratings before and two weeks after the injection. LSS patients improved less two weeks following the ESI than HD patients (P = 0.04). Just 38% of LSS patients reported improvement in pain score compared with 61% of HD patients. In analyses that combined LSS and HD patients, predictors of worse response included a report of health problems and a diagnosis of LSS., Conclusions: LSS patients have worse response to ESIs than HD patients. The poor response to ESI in patients with LSS underscores the need for randomized controlled trials of ESI in this population.

Background and Objectives: This study examined the effectiveness of sphenopalatine ganglion block (SPGB) for myofascial pain syndrome of the head, neck, and shoulders using a double-blind, placebo-controlled, crossover study design with comparison to an internal standard consisting of trigger point injections (TPI)., Methods: Patients (n = 23) were randomly assigned to receive either: (1) SPGB with 4% lidocaine, then TPI with 1% lidocaine, and finally SPGB with saline placebo or (2) SPGB with saline placebo, then TPI with 1% lidocaine, and finally SPGB with 4% lidocaine. Each respective treatment within each protocol was given sequentially at 1-week intervals for both groups. Prior to the first treatment, all patients assessed their average intensity of pain and pain at that particular moment using a visual analog pain scale. Pain intensity and pain relief were reassessed 30 minutes after each treatment and at 6 hours, 24 hours and 1 week using visual analog pain and pain relief scales. Pain intensity and pain relief data were transformed into natural logarithm units, and the statistical significance of SPGB with 4% lidocaine versus SPGB with placebo, SPGB with 4% lidocaine versus TPI, and TPI versus SPGB with placebo were tested by mixed-model analysis of variance. The magnitude of the differences in pain intensity and pain relief ratings were also compared via computation of 95% confidence intervals., Results: The analgesic effect of SPGB with 4% lidocaine was no better than placebo. Mixed-model analysis of variance revealed improved analgesia with administration of TPIs as compared to SPGB with 4% lidocaine and placebo over the entire week of observations (pain relief scores)., Conclusions: This study suggests that SPGB with 4% lidocaine is no more efficacious than placebo and less efficacious than administration of standard trigger point injections in the treatment of myofascial pain of the head, neck, and shoulders.

Distressing postoperative pain remains a prevalent problem. Poorly treated pain contributes to patient suffering and may prevent rapid recovery and rehabilitation. An understanding and application of the basic principles of pain management can provide adequate analgesia for the majority of postoperative patients. More advanced methods of pain control can allow excellent relief for virtually all patients but may require the presence of a dedicated pain management service. This article reviews the principles and practice of modern postoperative pain management.

This study was performed in order to determine concentration-effect, and graded and quantal dose-response relationships for the clinical administration of intravenous (IV) lidocaine to patients with neuropathic pain. Thirteen patients were administered 500 mg of IV lidocaine at a rate of 8.35 mg/min over 60 min. Visual analog pain scores and venous blood samples were obtained concomitantly at 10 min intervals for 60 min. Blood samples were also obtained for determination of serum and serum water lidocaine concentrations at the onset of analgesia and at the time complete pain relief was attained. Lidocaine concentrations were determined by gas chromatography. Graded dose-response curves were prepared individually and for the group as a whole, and a quantal dose-response curve was prepared for the entire group. The dose-response relationship for IV lidocaine was characterized by large increases in pain relief for concomitant minimal increases in dosage. The difference between the ED50 (372.0 mg) and the ED90 (416.5 mg) was 44.5 mg of lidocaine (5.3 min of infusion). The concentration-effect relationship was also steep with pain scores abruptly decreasing over a range of 0.62 microgram/mL of lidocaine. Interestingly, the free concentration of lidocaine had no better correlation with the onset of analgesia or the attainment of complete analgesia than the serum concentration of lidocaine. This suggests that the mechanism of analgesia to IV lidocaine may not be based upon a conventional concentration-effect relationship. In conclusion, the results of this study suggest that the analgesic response to IV lidocaine is best characterized by a precipitous "break in pain" over a narrow dosage and concentration range.

Objective: To compare the utility of 0.0625% bupivacaine with fentanyl administered via patient-controlled epidural analgesia (PCEA) to a traditional continuous epidural infusion for pain of labor and delivery., Design and Subjects: Forty-one women in established labor were randomized to receive either (a) 0.0625% bupivacaine with 2 micrograms/ml fentanyl via PCEA (demand dose = 3 ml, lockout interval = 6 min, background infusion = 6 ml/h, no 1 or 4 h limits) or (b) 0.125% bupivacaine with 2 micrograms/ml fentanyl via continuous epidural infusion (CEI) at 12 ml/h. Supplemental 0.25% bupivacaine (3 ml every 5 min, p.r.n., x 3) was administered for treatment of breakthrough pain upon patient request. The study protocol was double-blind and placebo-controlled., Outcome Measures: Visual analogue pain scores, motor strength, pinprick level of sensory analgesia and bupivacaine use were assessed by an anesthesiologist unaware of the individual patient's randomization to a particular study group., Results: The cephalad extent of pinprick sensory analgesia was significantly lower during both the first (p < 0.03) and second (p < 0.03) stages of labor in patients receiving PCEA. However, visual analogue pain scores, intensity of motor blockade, and need for physician-administered supplemental bupivacaine were comparable in both groups. Patients receiving PCEA used 40% less bupivacaine per hour while achieving analgesia comparable to patients receiving CEI., Conclusions: The results of this study show that 0.0625% bupivacaine with 2 micrograms/ml of fentanyl is an effective analgesic combination when used via PCEA.

The use of a background infusion with intravenous patient-controlled analgesia (IV-PCA) increases drug consumption without any additional contribution to analgesia. There are no data on the potential advantage of a background infusion administered with patient-controlled epidural analgesia (PCEA) for labor and delivery. Sixty women were randomized to one of four groups and received either: (a) demand dose PCEA (demand dose = 3 mL; lockout interval = 10 min); (b) continuous infusion plus demand dose PCEA (two separate infusion rates: 3 mL/h and 6 mL/h); or (c) a fixed-rate continuous epidural infusion (CEI) at 12 mL/h. All patients received 0.125% bupivacaine with 2 micrograms/mL of fentanyl. The study protocol was double-blind and placebo-controlled. Visual analog pain scores, motor strength, and bilateral pinprick analgesia were assessed every half hour by a blinded observer. Pain scores, cephalad extent of sensory analgesia, and motor block were no different among the study groups during the first and second stages of labor. Cumulative hourly bupivacaine use was similar among all PCEA study groups. However, use of PCEA (in whatever mode) provided a 35% dose-sparing effect in comparison to CEI. The PCEA groups receiving no background infusion or a 3-mL/h background infusion had a greater need for physician-administered supplemental bupivacaine during the first stage of labor. While not statistically significant, a trend toward increased need for supplementation was seen in these same patient groups over the entire course of labor and delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Background and Objectives: Opioids have been accepted as appropriate treatment for acute and cancer pain, but remain controversial for use with chronic nonmalignant pain. Clinicians are concerned about efficacy, tolerance, addiction, and unwanted side effects., Methods: The aim of this study was to survey chronic pain patients who were taking opioids for their pain, to determine the incidence of these adverse conditions. Two hundred seventeen patients who were being treated for their pain at two different pain centers completed a medication questionnaire. The most common diagnosis was low back pain. One hundred twelve patients reported taking oral opioids for their pain., Results: Of the patients who reported taking opioids for their chronic pain, 83% felt that the opioids were moderately beneficial in relieving their pain; 25% felt that the opioid had not lost its ability to relieve the pain over time; 35% reported that they did not need to increase their medication; 36% expressed no fear of addiction or dependence; and 56% reported having no unwanted side effects., Conclusions: The results suggest that chronic nonmalignant pain patients taking opioids for their pain reported some tolerance, fear of addiction, and side effects when taking opioids. However, despite these concerns, some of these patients felt that opioid therapy was very beneficial. Further investigations are needed to determine which patient characteristics predict benefit from opioid therapy for nonmalignant pain.

The epidural administration of morphine and fentanyl delay the regression of sensory anesthesia in postoperative patients receiving epidural bupivacaine. This study was performed to determine any differential effects of two lipid-soluble opioids upon regression of sensory anesthesia during coadministration with epidural bupivacaine. Forty-eight patients scheduled for total knee replacement underwent lumbar epidural catheterization and received 1.5% etidocaine with 1:200,000 epinephrine to establish sensory anesthesia to approximately T6 bilaterally. Patients were randomized by the investigational pharmacy to receive either: (a) bupivacaine without opioid (control) (n = 16), or (b) bupivacaine with 1 mg/mL of meperidine (n = 16), or (c) bupivacaine with 3 micrograms/mL of fentanyl (n = 16) in a double-blind fashion. Intraoperatively, 0.5% bupivacaine +/- opioid was administered by epidural infusion at a rate of 10 mL/h. Postoperatively, the bupivacaine concentration was decreased to 0.25% (+/- the same opioid), and the infusion rate was decreased to 4 mL/h. Pinprick sensory anesthesia and verbal numerical pain score were recorded each hour after surgery by a blinded investigator. For each patient, the study was considered terminated when the cephalad level of sensory anesthesia bilaterally decreased five dermatomal segments or the pain score reached "5" (moderate pain). Patients receiving epidural infusions of bupivacaine and meperidine had a significantly slower regression of sensory anesthesia and slower development of pain. There was no difference in the rate of regression of sensory anesthesia or the development of pain among patients receiving bupivacaine alone or bupivacaine with fentanyl.

Study Objective: To test the hypothesis that alkalinization of lidocaine decreases the pain of skin infiltration in surgical patients., Design: Double-blind, randomized, prospective study., Setting: Preoperative holding units, Brigham and Women's Hospital., Patients: 184 adult surgical patients., Interventions: We compared the efficacy of 1% lidocaine with and without 0.1 mEq/ml of sodium bicarbonate (NaHCO3) for relief of pain of (1) skin infiltration and (2) intravenous (i.v.) catheterization prior to surgery., Measurements and Main Results: Patients evaluated the intensity of pain using a 100 mm visual analog scale (VAS). There were no differences between study groups (lidocaine with NaHCO3, n = 89; lidocaine alone, n = 95) with respect to site of catheterization or catheter gauge used. Lidocaine plus NaHCO3 caused significantly less pain on skin infiltration (median VAS = 4; range = 0 to 51) than did lidocaine alone (VAS = 8; range = 0 to 48; p < 0.008). Pain of i.v. catheterization also did not differ between groups. There was a weak correlation between catheter gauge and pain of i.v. catheterization (r = -0.19; p = 0.01)., Conclusions: Pain resulting from skin infiltration of lidocaine solutions can be diminished by adding NaHCO3. However, catheter size is more important than the presence or absence of NaHCO3 in determining the pain of i.v. catheterization.

Despite intravenous patient-controlled analgesia's (IV-PCA) increasing popularity, the psychological and pharmacological factors upon which patient satisfaction with IV-PCA are based are unknown. Sixty-eight women scheduled for abdominal hysterectomy completed a series of questionnaires measuring emotional distress, locus of control, perceived support, and optimism before their surgery. Postoperative ratings of pain intensity, emotional distress, anticipated recovery time, nightmares, and satisfaction with IV-PCA were taken 1 and 3 days after surgery. A nurse observer rated perceived anxiety, estimated recovery, and satisfaction with IV-PCA. Cumulative and hourly IV-PCA use and dose/demand ratio were obtained. Degree of dissatisfaction with IV-PCA was significantly correlated with pain intensity, nightmares, patient's perceptions of support, expectations of recovery, preoperative anxiety, and postoperative depression. Dose/demand ratio and hourly analgesic usage were significantly related to pre- and postoperative emotional distress factors. Perioperative management of anxiety, perceptions, and expectations may prove valuable in improving pain control and satisfaction with IV-PCA.