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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: 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]

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: 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.

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.

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.

This study examined factors that help to identify low back pain patients who do not benefit from a lumbar epidural steroid injection (LESI). Two-hundred and forty-nine chronic low back pain patients assessed their pain intensity before, 1 day after, and 2 weeks after receiving a LESI. All patients completed a comprehensive pain questionnaire and a Brief Symptom Inventory (BSI) prior to treatment. Diagnosis and extent of pathology were independently assessed by two physicians. One-hundred and thirty-one patients (52.6%) were followed 1 year after treatment. Results showed that average pain intensity ratings decreased in 62.3% of patients 2 weeks after receiving a LESI. One year after treatment, 62.6% felt that LESI was helpful. Nine patients (7%) felt that the treatment was harmful. Four factors were identified that best predicted poor outcome 2 weeks after LESI: (a) greater number of previous treatments for pain; (b) more medications taken; (c) pain not necessarily increased by activities, and (d) pain increased by coughing. Factors that predicted no benefit 1 year after treatment included (a) pain does not interfere with activities; (b) unemployment due to pain; (c) normal straight-leg raise test prior to treatment; and (d) pain not decreased by medication.

A double-blind, placebo-controlled study was designed to compare the efficacy of demand-dose patient-controlled epidural analgesia (PCEA) with continuous epidural infusion (CEI) for treatment of pain during labor and delivery. Forty patients were randomized to receive 0.125% bupivacaine with fentanyl (2 micrograms/mL) through CEI at 12 mL/h or through demand-dose PCEA. Patients using PCEA could demand 3 mL every 10 min without restriction. Analgesia in both groups was comparable. However, there was a significant reduction in total bupivacaine consumption (in milligrams) associated with the use of PCEA (mean +/- SEM: CEI = 76.1 +/- 8.5 mg; PCEA = 42.2 +/- 5.9 mg; 45% reduction). The hourly bupivacaine consumption during the first (CEI = 15.8 +/- 0.6 mg/h; PCEA = 8.8 +/- 1.1 mg/h) and second (CEI = 17.2 +/- 1.2 mg/h; PCEA = 6.8 +/- 1.2 mg/h) stages of labor was also reduced. Overall, this represented a 47% "sparing" of bupivacaine use per hour with PCEA. Similar reductions occurred in the use of fentanyl. The reductions in analgesic requirement, however, were not associated with a reduction in the degree of motor blockade or in the cephalad extent of sensory blockade. A significant dose-sparing effect was associated with the use of demand-dose PCEA as compared with standard CEI for analgesia during labor and delivery.

Acute and chronic pain are different clinical entities. Acute pain is provoked by a specific disease or injury, serves a useful biologic purpose, is associated with skeletal muscle spasm and sympathetic nervous system activation, and is self-limited. Chronic pain, in contrast, may be considered a disease state. It is pain that outlasts the normal time of healing, if associated with a disease or injury. Chronic pain may arise from psychological states, serves no biologic purpose, and has no recognizable end-point. Both acute and chronic pain are an enormous problem in the United States, costing 650 million lost workdays and $65 billion a year. The therapy of acute pain is aimed at treating the underlying cause and interrupting the nociceptive signals. The therapy of chronic pain must rely on a multidisciplinary approach and should involve more than one therapeutic modality.

We examined the effects of the following variables on interpleural analgesia after thoracotomy: addition of epinephrine to local anesthetic, thoracostomy drainage, two-catheter placement, and location of catheter tips. Twenty patients were randomized to have one catheter (paravertebral tip location) or two catheters (paravertebral and lateral thoracic wall tip locations). Interpleural catheters were sutured to the parietal pleura by the surgeon at time of wound closure. Patients were then randomly assigned to receive 20 mL of 0.5% bupivacaine with 1:200,000 epinephrine through the single catheter or 10 mL of 0.5% bupivacaine with or without 1:200,000 epinephrine through each of the two catheters while supine. Bupivacaine concentrations in whole blood and in thoracostomy drainage fluid were assayed by gas chromatography. Actual content of bupivacaine in the drainage fluid was calculated. Degree of analgesia was assessed by verbal numerical pain scores over the first 4 h and opioid demand thereafter. Addition of epinephrine to bupivacaine did not influence the degree of analgesia. Approximately 30%-40% of any administered dose of bupivacaine was lost via the thoracostomy tube over a 4-h period. There was no correlation between the true initial dose (100 mg minus thoracostomy drainage) and Cmax. Use of two catheters resulted in significantly less opioid requirements after an initial 8-h period. Failure to achieve adequate interpleural analgesia in postthoracotomy patients may be related to loss of anesthetic via thoracostomy drainage, presence of extravasated blood and tissue fluid in the pleural space, and possibly sequestration and channeling of flow of local anesthetic by restricted motion of an operated lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Traditional techniques of epidural needle placement have not proved satisfactory in patients who have had a previous laminectomy and may have epiduroarachnoiditis. A two-person technique was developed to: 1) simplify performance of difficult, epidural needle placement; 2) allow both resident and staff a simultaneous "hands-on" teaching experience; 3) allow a painless method of medication administration in patients with altered epidural anatomy; and 4) allow a simple method for determination of epidural space pressures. A glass syringe and extension tubing filled with saline are connected to the epidural needle. The needle is advanced by the operator while the pressure is monitored by the assistant. Once in the epidural space, the extension tubing is held vertically to act as a manometer. The column of saline falls and fluctuates with heart beat, providing verification of correct needle placement. Medication is placed in the barrel of the syringe and allowed to infuse by gravity. The two-person technique has achieved both patient and resident acceptance, and allows a painless method of medication administration in patients with altered epidural space anatomy.

A statistical model was developed: 1) to compare the efficacy of patient-controlled analgesia (PCA) and traditional intramuscular (IM) opioids for pain relief in 40 patients after total knee replacement and, 2) to evaluate pain cycles associated with each technique. Hourly visual analog pain scores were subjected to two-way analysis of variance (ANOVA) and time-series analysis. Hourly verbal analog pain scores were used to determine predominant pain levels. According to ANOVA, PCA was no more effective than were IM opioids. Time-series analyses documented a complete cycle of pain every 5.3 hours in patients receiving IM opioids but no pain cycle with use of PCA. Analysis of PCA verbal analog scores demonstrated self-administration of opioids to "moderate" levels of pain relief with use of PCA, not to complete analgesia. These results suggest that certain patients may not envision complete postoperative analgesia as being possible. Hence, they self-administer opioids for pain relief with PCA according to their expectations. Population characteristics may modify PCA efficacy. These characteristics should be delineated and the use of PCA targeted to appropriate patients.