Increased Central Nervous System Interleukin-8 in a Majority Postlaminectomy Syndrome Chronic Pain Population.

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.

Efficacy of needle-placement technique in radiofrequency ablation for treatment of lumbar facet arthropathy.

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.

Botulinum toxin type a injections for cervical and shoulder girdle myofascial pain using an enriched protocol design.

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.

Medical practice perspective: identification and mitigation of risk factors for mortality associated with intrathecal opioids for non-cancer 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.

Mortality associated with implantation and management of intrathecal opioid drug infusion systems to treat noncancer pain.

BACKGROUND: In 2006, the authors observed a cluster of three deaths, which circumstances suggested were opioid-related, within 1 day after placement of intrathecal opioid pumps for noncancer pain. Further investigation suggested that mortality among such patients was higher than previously appreciated. The authors performed investigations to quantify that mortality and compare the results to control populations, including spinal cord stimulation and low back surgery. METHODS: After analyzing nine index cases--three sentinel cases and six identified by a prospective strategy--the authors used epidemiological methods to investigate whether mortality rates reflected patient- or therapy-related differences. Mortality rates after intrathecal opioid therapy and spinal cord stimulation were derived by correlating Medtronic device registration data with de-identified data from the Social Security Death Master File. Aggregate demographic and comorbidity data were obtained from Medicare and United Healthcare population databases to examine the influence of demographics and comorbidities on mortality. RESULTS: Device registration and Social Security analyses revealed an intrathecal opioid therapy mortality rate of 0.088% at 3 days after implantation, 0.39% at 1 month, and 3.89% at 1 yr-a higher mortality than after spinal cord stimulation implants or after lumbar diskectomy in community hospitals. Demographic, illness profile, and mortality analyses of large databases suggest, despite limitations, that excess mortality was related to intrathecal opioid therapy, and could not be fully explained by other factors. These findings were consistent with the nine index cases that revealed that respiratory arrest caused or contributed to death in all patients. No device malfunctions associated with overinfusion were identified among cases where data were available. CONCLUSIONS: Patients with noncancer pain treated with intrathecal opioid therapy experience increased mortality compared to similar patients treated by using other therapies. Respiratory depression as a consequence of intrathecal drug overdosage or mixed intrathecal and systemic drug interactions is one plausible, but hypothetical mechanism. The exact causes for patient deaths and the proportion of those deaths attributable to intrathecal opioid therapy remain to be determined. These findings, although based on incomplete information, suggest that it may be possible to reduce mortality in noncancer intrathecal opioid therapy patients.

Diagnosis of unintentional subdural anesthesia/analgesia: analyzing radiographically proven cases to define the clinical entity and to develop a diagnostic algorithm.

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.

Health-related quality of life in sacroiliac syndrome: a comparison to lumbosacral radiculopathy.

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.

New onset lumbar radicular pain after implantation of an intrathecal drug delivery system: imaging catheter migration.

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.

Evidence against trigger point injection technique for the treatment of cervicothoracic myofascial pain with botulinum toxin type A.

BACKGROUND: Traditional strategies for myofascial pain relief provide transient, incomplete, variable, or unpredictable outcomes. Botulinum toxin is itself an analgesic but can also cause sustained muscular relaxation, thereby possibly affording even greater relief than traditional therapies. METHODS: The study goal was to determine whether direct injection of botulinum toxin type A (BoNT-A) into trigger points was efficacious for cervicothoracic myofascial pain, and if so, to determine the presence or absence of a dose-response relation. One hundred thirty-two patients with cervical or shoulder myofascial pain or both and active trigger points were enrolled in a 12-week, randomized, double-blind, placebo-controlled trial. After a 2-week washout period for all medications, patients were injected with either saline or 10, 25, or 50 U BoNT-A into up to five active trigger points. The maximum doses in each experimental group were 0, 50, 125, and 250 U per patient, respectively. Patients subsequently received myofascial release physical therapy and amitriptyline, ibuprofen, and propoxyphene-acetaminophen napsylate. Follow-up visits occurred at 1, 2, 4, 6, 8, and 12 weeks. Outcome measures included visual analog pain scores, pain threshold as measured by pressure algometry, and rescue dose use of propoxyphene-acetaminophen napsylate. RESULTS: No significant differences occurred between placebo and BoNT-A groups with respect to visual analog pain scores, pressure algometry, and rescue medication. CONCLUSIONS: Injection of BoNT-A directly into trigger points did not improve cervicothoracic myofascial pain. The role of direct injection of trigger points with BoNT-A is discussed in comparison to other injection methodologies in the potential genesis of pain relief.

Conversion disorder mimicking Dejerine-Roussy syndrome (thalamic stroke) after spinal cord stimulation.

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.

Intrathecal bupivacaine for chronic pain: a review of current knowledge.

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.