Raman Microscopy Investigation of GLP-1 Peptide Association with Supported Phospholipid Bilayers

A wide range of important biological processes occur at phospholipid membranes including cell signaling, where a peptide or small molecule targets a membrane-localized receptor protein. In this work, we report the adaptation of confocal Raman microscopy to quantify populations of unlabeled glucagon-like peptide-1 (GLP-1), a membrane-active 30-residue incretin peptide, in supported phospholipid bilayers deposited on the interior surfaces of wide-pore porous silica particles. Quantification of lipid bilayer-associated peptide is achieved by measuring the Raman scattering intensity of the peptide relative to that of the supported lipid bilayer, which serves as an internal standard. The dependence of the bilayer-associated GLP-1 population on the solution concentration of GLP-1 produces an isotherm used to determine the equilibrium constant for peptide-bilayer association and the maximum peptide surface coverage. The maximum coverage of GLP-1 in the lipid bilayer was found to be only 1/5th of a full monolayer based on its hydrodynamic radius. The saturation coverage, therefore, is not limited by the size of GLP-1 but by the ability of the bilayer to accommodate the peptide at high concentrations within the bilayer. Raman spectra show that GLP-1 association with the supported bilayer is accompanied by structural changes consistent with the intercalation of the peptide into the bilayer, where the observed increase in acyl-chain order would increase the lipid density and provide free volume needed to accommodate the peptide. These results were compared with previous measurements of the association of fluorescently labeled GLP-1 with a planar-supported bilayer; the unlabeled peptide exhibits a 3-fold greater affinity for the lipid bilayer on the porous silica support, suggesting that the fluorescent label alters the GLP-1 lipid bilayer association.

Epidural Interventions in the Management of Chronic Spinal Pain: American Society of Interventional Pain Physicians (ASIPP) Comprehensive Evidence-Based Guidelines

BACKGROUND

Chronic spinal pain is the most prevalent chronic disease with employment of multiple modes of interventional techniques including epidural interventions. Multiple randomized controlled trials (RCTs), observational studies, systematic reviews, and guidelines have been published. The recent review of the utilization patterns and expenditures show that there has been a decline in utilization of epidural injections with decrease in inflation adjusted costs from 2009 to 2018. The American Society of Interventional Pain Physicians (ASIPP) published guidelines for interventional techniques in 2013, and guidelines for facet joint interventions in 2020. Consequently, these guidelines have been prepared to update previously existing guidelines.

OBJECTIVE

To provide evidence-based guidance in performing therapeutic epidural procedures, including caudal, interlaminar in lumbar, cervical, and thoracic spinal regions, transforaminal in lumbar spine, and percutaneous adhesiolysis in the lumbar spine.

METHODS

The methodology utilized included the development of objective and key questions with utilization of trustworthy standards. The literature pertaining to all aspects of epidural interventions was viewed with best evidence synthesis of available literature and  recommendations were provided.

RESULTS

In preparation of the guidelines, extensive literature review was performed. In addition to review of multiple manuscripts in reference to utilization, expenditures, anatomical and pathophysiological considerations, pharmacological and harmful effects of drugs and procedures, for evidence synthesis we have included 47 systematic reviews and 43 RCTs covering all epidural interventions to meet the objectives.The evidence recommendations are as follows: Disc herniation: Based on relevant, high-quality fluoroscopically guided epidural injections, with or without steroids, and results of previous systematic reviews, the evidence is Level I for caudal epidural injections, lumbar interlaminar epidural injections, lumbar transforaminal epidural injections, and cervical interlaminar epidural injections with strong recommendation for long-term effectiveness.The evidence for percutaneous adhesiolysis in managing disc herniation based on one high-quality, placebo-controlled RCT is Level II with moderate to strong recommendation for long-term improvement in patients nonresponsive to conservative management and fluoroscopically guided epidural injections. For thoracic disc herniation, based on one relevant, high-quality RCT of thoracic epidural with fluoroscopic guidance, with or without steroids, the evidence is Level II with moderate to strong recommendation for long-term effectiveness.Spinal stenosis: The evidence based on one high-quality RCT in each category the evidence is Level III to II for fluoroscopically guided caudal epidural injections with moderate to strong recommendation and Level II for fluoroscopically guided lumbar and cervical interlaminar epidural injections with moderate to strong recommendation for long-term effectiveness.The evidence for lumbar transforaminal epidural injections is Level IV to III with moderate recommendation with fluoroscopically guided lumbar transforaminal epidural injections for long-term improvement. The evidence for percutaneous adhesiolysis in lumbar stenosis based on relevant, moderate to high quality RCTs, observational studies, and systematic reviews is Level II with moderate to strong recommendation for long-term improvement after failure of conservative management and fluoroscopically guided epidural injections. Axial discogenic pain: The evidence for axial discogenic pain without facet joint pain or sacroiliac joint pain in the lumbar and cervical spine with fluoroscopically guided caudal, lumbar and cervical interlaminar epidural injections, based on one relevant high quality RCT in each category is Level II with moderate to strong recommendation for long-term improvement, with or without steroids. Post-surgery syndrome: The evidence for lumbar and cervical post-surgery syndrome based on one relevant, high-quality RCT with fluoroscopic guidance for caudal and cervical interlaminar epidural injections, with or without steroids, is Level II with moderate to strong recommendation for long-term improvement. For percutaneous adhesiolysis, based on multiple moderate to high-quality RCTs and systematic reviews, the evidence is Level I with strong recommendation for long-term improvement after failure of conservative management and fluoroscopically guided epidural injections.

LIMITATIONS

The limitations of these guidelines include a continued paucity of high-quality studies for some techniques and various conditions including spinal stenosis, post-surgery syndrome, and discogenic pain.

CONCLUSIONS

These epidural intervention guidelines including percutaneous adhesiolysis were prepared with a comprehensive review of the literature with methodologic quality assessment and determination of level of evidence with strength of recommendations.

Confocal Raman Microscopy Investigation of Phospholipid Monolayers Deposited on Nitrile-Modified Surfaces in Porous Silica Particles

Phospholipid bilayers deposited on a variety of surfaces provide models for investigation of the lipid membrane structure and supports for biocompatible sensors. Hybrid-supported phospholipid bilayers (HSLBs) are stable membrane models for these investigations, typically prepared by self-assembly of a lipid monolayer over an n-alkane-modified surface. HSLBs have been prepared on n-alkyl chain-modified silica and used for lipophilicity-based chromatographic separations. The structure of these hybrid bilayers differs from vesicle membranes where the lipid head group spacing is greater due to interdigitation of the lipid acyl chains with the underlying n-alkyl chains bound to the silica surface. This interdigitated structure exhibits a broader melting transition at a higher temperature due to strong interactions between the lipid acyl chains and the immobile n-alkyl chains bound to silica. In the present work, we seek to reduce the interactions between a lipid monolayer and its supporting substrate by self-assembly of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) on porous silica functionalized with nitrile-terminated surface ligands. The frequency of Raman scattering of the surface -C≡N stretching mode at the lipid-nitrile interface is consistent with an n-alkane-like environment and insensitive to lipid head group charge, indicating that the lipid acyl chains are in contact with the surface nitrile groups. The head group area of this lipid monolayer was determined from the within-particle phospholipid concentration and silica specific surface area and found to be 54 ± 2 Ų, equivalent to the head group area of a DMPC vesicle bilayer. The structure of these nitrile-supported phospholipid monolayers was characterized below and above their melting transition by confocal Raman microscopy and found to be nearly identical to DMPC vesicle bilayers. Their narrow gel-to-fluid-phase melting transition is equivalent to dispersed DMPC vesicles, suggesting that the acyl chain structure on the nitrile support mimics the outer leaflet structure of a vesicle membrane.

Confocal Raman Microscopy Investigation of Self-Assembly of Hybrid Phospholipid Bilayers within Individual Porous Silica Chromatographic Particles

Hybrid-supported phospholipid bilayers are a model structure utilized for measurement of molecular interactions that typically occur at cell membranes. These membrane models are prepared by adsorption of a lipid monolayer onto a stable n-alkyl chain layer that is covalently bound to a support surface. Hybrid bilayers have been adapted to chromatographic retention measurements of lipophilicity through the assembly of a phospholipid monolayer onto n-alkane-modified silica surfaces in reversed-phase chromatographic particles. Recent Raman microscopy studies of these particles have shown that the acyl chains of the phospholipid interact with the C₁₈-alkyl chains immobilized on the silica surface, where both lipid and C₁₈ alkyl chains become ordered because of chain interdigitation. Confocal Raman microscopy has also been used to investigate the association of small molecules with hybrid-lipid bilayers in C₁₈ chromatographic silica particles; the partitioning of model solutes compares favorably to that in lipid vesicle membranes with similar changes in acyl-chain structure (disordering) with solute partitioning. The present study seeks information about how these membrane-mimetic bilayers assemble onto the C₁₈-derivatized silica surfaces of reversed-phase chromatographic silica particles. Confocal Raman microscopy is capable of interrogating the time-dependent internal composition and structure within individual silica particles. The Raman scattering data can be resolved into component Raman spectra and corresponding composition vectors that describe the time-dependent changes in intensity of the component spectra. This analysis provides insight into how the structures of both the lipid and C₁₈ alkyl chains of hybrid lipid bilayers evolve during deposition and organization on the internal surfaces of reversed-phase chromatographic silica particles.

Confocal Raman Microscopy for in Situ Measurement of Phospholipid-Water Partitioning into Model Phospholipid Bilayers within Individual Chromatographic Particles

The phospholipid-water partition coefficient is a commonly measured parameter that correlates with drug efficacy, small-molecule toxicity, and accumulation of molecules in biological systems in the environment. Despite the utility of this parameter, methods for measuring phospholipid-water partition coefficients are limited. This is due to the difficulty of making quantitative measurements in vesicle membranes or supported phospholipid bilayers, both of which are small-volume phases that challenge the sensitivity of many analytical techniques. In this work, we employ in situ confocal Raman microscopy to probe the partitioning of a model membrane-active compound, 2-(4-isobutylphenyl) propionic acid or ibuprofen, into both hybrid- and supported-phospholipid bilayers deposited on the pore walls of individual chromatographic particles. The large surface-area-to-volume ratio of chromatographic silica allows interrogation of a significant lipid bilayer area within a very small volume. The local phospholipid concentration within a confocal probe volume inside the particle can be as high as 0.5 M, which overcomes the sensitivity limitations of making measurements in the limited membrane areas of single vesicles or planar supported bilayers. Quantitative determination of ibuprofen partitioning is achieved by using the phospholipid acyl-chains of the within-particle bilayer as an internal standard. This approach is tested for measurements of pH-dependent partitioning of ibuprofen into both hybrid-lipid and supported-lipid bilayers within silica particles, and the results are compared with octanol-water partitioning and with partitioning into individual optically trapped phospholipid vesicle membranes. Additionally, the impact of ibuprofen partitioning on bilayer structure is evaluated for both within-particle model membranes and compared with the structural impacts of partitioning into vesicle lipid bilayers.

Implementing Population Medicine in a Pain Management Practice

PURPOSE

To document and improve the quality of our chronic pain management using population management methods.

METHODS

An analytic registry was developed, and all new patients were enrolled for 12 months. Patient demographics, standardized pain and function measures, and treatments were recorded. Usual care was provided. The registry was used to organize care and analyze management and outcomes.

RESULTS

Of 454 total patients, only 154 (34%) completed a 6-month cycle of care. High no-show rates were documented for follow-up appointments for several reasons. The majority of 6-month completers showed improved pain levels.

DISCUSSION

This quality improvement project identified assessment and care gaps and led to improvements. An ongoing need to improve measures of pain and function was documented.

Raman Spectroscopy Reveals Selective Interactions of Cytochrome c with Cardiolipin That Correlate with Membrane Permeability

Permeabilization of the outer mitochondrial membrane is an integral step in apoptosis. The resulting release of pro-apoptotic signaling proteins leads to cell destruction through activation of the cysteine-aspartic protease (caspase) cascade. However, the mechanism of outer mitochondrial membrane (OMM) permeabilization remains unclear. It was recently shown that cytochrome c can induce pore formation in cardiolipin-containing phospholipid membranes, leading to large dextran and protein permeability. In this work, the interaction of cytochrome c with cardiolipin-containing phospholipid vesicles, serving as models of the OMM, is investigated to probe cytochrome c-induced permeability. Lipid vesicles having either a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or mixed-DPPC/cardiolipin membrane and containing a membrane-impermeable Raman tracer 3-nitrobenzenesulfonate (3-NBS) were optically trapped, translated into a solution containing cytochrome c, and monitored for 3-NBS leakage. Cytochrome-correlated leakage was observed only in cardiolipin-containing vesicles. Structural changes observed in the Raman spectra during permeabilization indicated acyl chain disordering along with decreased intensity of the cardiolipin cis-double-bond stretching modes. When the vesicle-associated cytochrome c Raman spectrum is compared with a spectrum in buffer, heme-resonance bands are absent, indicating loss of Met-80 coordination. To verify selective interactions of cytochrome c with cardiolipin, these experiments were repeated where the DPPC acyl chains were deuterated (D62-DPPC), allowing spectral resolution of the DPPC acyl chain response from that of cardiolipin. Interestingly, D62-DPPC acyl chains were unaffected by cytochrome c accumulation, while cardiolipin showed major changes in acyl chain structure. These results suggest that cytochrome-induced permeabilization proceeds through selective interaction of cytochrome c with cardiolipin, resulting in protein unfolding, where the unfolded form interacts with cardiolipin acyl chains within the bilayer to induce permeability.

Confocal Raman Microscopy Investigation of Molecular Transport into Individual Chromatographic Silica Particles

Porous silica is used as a support in a variety of separation processes, including chromatographic separation and solid-phase extraction. The resolution and efficiency of these applications is significantly impacted by the kinetics of partitioning and molecular transport into the interior of the porous particles. Molecular transport in porous silica has been explored previously by measuring chromatographic elution profiles, but such measurements are limited to relatively low retention conditions, where within-particle molecular transport must be inferred from elution profiles of solutes emerging from a packed column. In this work, a measurement of within-particle molecular transport is carried out using confocal Raman microscopy to probe the time-dependent accumulation of pyrene from an aqueous mobile phase into the center of individual C₁₈-chromatographic particles. The measured time constants for pyrene accumulation were much slower than diffusion-limited transport of solute in solution to the particle surface. Furthermore, the accumulation into the center of the particle did not show a time-lag characteristic of slow-transport into the particle interior. The exponential rise of pyrene concentration is, however, consistent with first-order Langmuir adsorption kinetics at low surface coverages. The linear dependence of the time-constant on particle radius indicates an adsorption barrier near the outer boundary of the particle, where the accumulation rate depends on flux across the boundary (proportional to the particle area) to satisfy the within-particle capacity at equilibrium (proportional to the particle volume). The pyrene accumulation kinetics into the porous particle, expressed as a heterogeneous rate constant, were nearly 50-times faster than the pyrene adsorption rate at a planar C₁₈-functionalized silica surface, which demonstrates the impact of multiple surface encounters within the porous structure leading to much greater capture efficiency compared to a planar surface. Monte Carlo simulations of within-particle pyrene diffusion, with the adsorption efficiency estimated from the planar-surface adsorption rate, predict a diffusion-to-capture distance within the porous particle that is within 40% of that observed in the radial dependence of the pyrene within-particle accumulation results.

Calorimetry-Derived Composition Vectors to Resolve Component Raman Spectra in Phospholipid Phase Transitions

Multidimensional least squares analysis is a well-established technique for resolving component vibrational spectra from mixed samples or systems. Component resolution of temperature-dependent vibrational spectra is challenging, however, due to the lack of a suitable model for the variation in sample composition with temperature. In this work, analysis of temperature-dependent Raman spectra of lipid membranes is accomplished by using "concentration" vectors independently derived from enthalpy changes determined by differential scanning calorimetry. Specifically, the lipid-bilayer phase transitions of DMPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) are investigated through Raman spectra acquired from individual, optically trapped vesicles in suspension as a function of temperature. Heat capacity profiles of the same vesicle suspension are measured using differential scanning calorimetry and numerically integrated to generate enthalpy change curves of each phase transition, which are in turn used to construct composition vectors. Multidimensional least squares analysis optimized for a fit to these composition vectors allows resolution of the component spectra corresponding to gel, ripple, and liquid-crystalline phases of the DMPC. The quality of fit of the calorimetry-derived results is confirmed by unstructured residual differences between the data and the model, and a composition variation predicted by the resolved spectra that matches the calorimetry results. This approach to analysis of temperature-dependent spectral data could be readily applied in other areas of materials characterization, where one is seeking to learn about structural changes that occur through temperature-dependent phase transitions.

Determination of Organic Partitioning Coefficients in Water-Supercritical CO2 Systems by Simultaneous in Situ UV and Near-Infrared Spectroscopies

CO2 injected into depleted oil or gas reservoirs for long-term storage has the potential to mobilize organic compounds and distribute them between sediments and reservoir brines. Understanding this process is important when considering health and environmental risks, but little quantitative data currently exists on the partitioning of organics between supercritical CO2 and water. In this work, a high-pressure, in situ measurement capability was developed to assess the distribution of organics between CO2 and water at conditions relevant to deep underground storage of CO2. The apparatus consists of a titanium reactor with quartz windows, near-infrared and UV spectroscopic detectors, and switching valves that facilitate quantitative injection of organic reagents into the pressurized reactor. To demonstrate the utility of the system, partitioning coefficients were determined for benzene in water/supercritical CO2 over the range 35-65 °C and approximately 25-150 bar. Density changes in the CO2 phase with increasing pressure were shown to have dramatic impacts on benzene's partitioning behavior. Our partitioning coefficients were approximately 5-15 times lower than values previously determined by ex situ techniques that are prone to sampling losses. The in situ methodology reported here could be applied to quantify the distribution behavior of a wide range of organic compounds that may be present in geologic CO2 storage scenarios.

Spatial filtering of a diode laser beam for confocal Raman microscopy

With the development of single-longitudinal mode diode lasers, there has been an increase in using these sources for Raman spectroscopy. This is largely due to the cost-effectiveness of diode lasers, which offer savings not only in initial capital cost, but also electrical, cooling, and replacement costs over time, when compared with ion lasers. The use of diode-lasers in confocal Raman microscopy has remained a challenge, however, due to poor transverse beam quality. In this work, we present the design and implementation of a simple spatial filter capable of adapting a single-mode diode laser source to confocal Raman microscopy, yielding comparable spatial resolution as a gas-ion laser beam for profiling and optical-trapping applications. For profiling applications, spatial filtering improved x,y resolution of the beam by a factor 10, which in turn increased optical-trapping forces by ~90 times and yielded sevenfold greater Raman scattering signal intensity from an optically trapped phospholipid vesicle.

An update of comprehensive evidence-based guidelines for interventional techniques in chronic spinal pain. Part II: guidance and recommendations

OBJECTIVE

To develop evidence-based clinical practice guidelines for interventional techniques in the diagnosis and treatment of chronic spinal pain.

METHODOLOGY

Systematic assessment of the literature.

EVIDENCE

I. Lumbar Spine • The evidence for accuracy of diagnostic selective nerve root blocks is limited; whereas for lumbar provocation discography, it is fair. • The evidence for diagnostic lumbar facet joint nerve blocks and diagnostic sacroiliac intraarticular injections is good with 75% to 100% pain relief as criterion standard with controlled local anesthetic or placebo blocks. • The evidence is good in managing disc herniation or radiculitis for caudal, interlaminar, and transforaminal epidural injections; fair for axial or discogenic pain without disc herniation, radiculitis or facet joint pain with caudal, and interlaminar epidural injections, and limited for transforaminal epidural injections; fair for spinal stenosis with caudal, interlaminar, and transforaminal epidural injections; and fair for post surgery syndrome with caudal epidural injections and limited with transforaminal epidural injections. • The evidence for therapeutic facet joint interventions is good for conventional radiofrequency, limited for pulsed radiofrequency, fair to good for lumbar facet joint nerve blocks, and limited for intraarticular injections. • For sacroiliac joint interventions, the evidence for cooled radiofrequency neurotomy is fair; limited for intraarticular injections and periarticular injections; and limited for both pulsed radiofrequency and conventional radiofrequency neurotomy. • For lumbar percutaneous adhesiolysis, the evidence is fair in managing chronic low back and lower extremity pain secondary to post surgery syndrome and spinal stenosis. • For intradiscal procedures, the evidence for intradiscal electrothermal therapy (IDET) and biaculoplasty is limited to fair and is limited for discTRODE. • For percutaneous disc decompression, the evidence is limited for automated percutaneous lumbar discectomy (APLD), percutaneous lumbar laser disc decompression, and Dekompressor; and limited to fair for nucleoplasty for which the Centers for Medicare and Medicaid Services (CMS) has issued a noncoverage decision. II. Cervical Spine • The evidence for cervical provocation discography is limited; whereas the evidence for diagnostic cervical facet joint nerve blocks is good with a criterion standard of 75% or greater relief with controlled diagnostic blocks. • The evidence is good for cervical interlaminar epidural injections for cervical disc herniation or radiculitis; fair for axial or discogenic pain, spinal stenosis, and post cervical surgery syndrome. • The evidence for therapeutic cervical facet joint interventions is fair for conventional cervical radiofrequency neurotomy and cervical medial branch blocks, and limited for cervical intraarticular injections. III. Thoracic Spine • The evidence is limited for thoracic provocation discography and is good for diagnostic accuracy of thoracic facet joint nerve blocks with a criterion standard of at least 75% pain relief with controlled diagnostic blocks. • The evidence is fair for thoracic epidural injections in managing thoracic pain. • The evidence for therapeutic thoracic facet joint nerve blocks is fair, limited for radiofrequency neurotomy, and not available for thoracic intraarticular injections. IV. Implantables • The evidence is fair for spinal cord stimulation (SCS) in managing patients with failed back surgery syndrome (FBSS) and limited for implantable intrathecal drug administration systems. V. ANTICOAGULATION • There is good evidence for risk of thromboembolic phenomenon in patients with antithrombotic therapy if discontinued, spontaneous epidural hematomas with or without traumatic injury in patients with or without anticoagulant therapy to discontinue or normalize INR with warfarin therapy, and the lack of necessity of discontinuation of nonsteroidal anti-inflammatory drugs (NSAIDs), including low dose aspirin prior to performing interventional techniques. • There is fair evidence with excessive bleeding, including epidural hematoma formation with interventional techniques when antithrombotic therapy is continued, the risk of higher thromboembolic phenomenon than epidural hematomas with discontinuation of antiplatelet therapy prior to interventional techniques and to continue phosphodiesterase inhibitors (dipyridamole, cilostazol, and Aggrenox). • There is limited evidence to discontinue antiplatelet therapy with platelet aggregation inhibitors to avoid bleeding and epidural hematomas and/or to continue antiplatelet therapy (clopidogrel, ticlopidine, prasugrel) during interventional techniques to avoid cerebrovascular and cardiovascular thromboembolic fatalities. • There is limited evidence in reference to newer antithrombotic agents dabigatran (Pradaxa) and rivaroxan (Xarelto) to discontinue to avoid bleeding and epidural hematomas and are continued during interventional techniques to avoid cerebrovascular and cardiovascular thromboembolic events.

CONCLUSIONS

Evidence is fair to good for 62% of diagnostic and 52% of therapeutic interventions assessed.

DISCLAIMER

The authors are solely responsible for the content of this article. No statement on this article should be construed as an official position of ASIPP. The guidelines do not represent "standard of care."

American Society of Interventional Pain Physicians (ASIPP) guidelines for responsible opioid prescribing in chronic non-cancer pain: Part 2--guidance

RESULTS

Part 2 of the guidelines on responsible opioid prescribing provides the following recommendations for initiating and maintaining chronic opioid therapy of 90 days or longer. 1. A) Comprehensive assessment and documentation is recommended before initiating opioid therapy, including documentation of comprehensive history, general medical condition, psychosocial history, psychiatric status, and substance use history. (

EVIDENCE

good) B) Despite limited evidence for reliability and accuracy, screening for opioid use is recommended, as it will identify opioid abusers and reduce opioid abuse. (

EVIDENCE

limited) C) Prescription monitoring programs must be implemented, as they provide data on patterns of prescription usage, reduce prescription drug abuse or doctor shopping. (

EVIDENCE

good to fair) D) Urine drug testing (UDT) must be implemented from initiation along with subsequent adherence monitoring to decrease prescription drug abuse or illicit drug use when patients are in chronic pain management therapy. (

EVIDENCE

good) 2. A) Establish appropriate physical diagnosis and psychological diagnosis if available prior to initiating opioid therapy. (

EVIDENCE

good) B) Caution must be exercised in ordering various imaging and other evaluations, interpretation and communication with the patient, to avoid increased fear, activity restriction, requests for increased opioids, and maladaptive behaviors. (

EVIDENCE

good) C) Stratify patients into one of the 3 risk categories - low, medium, or high risk. D) A pain management consultation, may assist non-pain physicians, if high-dose opioid therapy is utilized. (

EVIDENCE

fair) 3. Essential to establish medical necessity prior to initiation or maintenance of opioid therapy. (

EVIDENCE

good) 4. Establish treatment goals of opioid therapy with regard to pain relief and improvement in function. (

EVIDENCE

good) 5. A) Long-acting opioids in high doses are recommended only in specific circumstances with severe intractable pain that is not amenable to short-acting or moderate doses of long-acting opioids, as there is no significant difference between long-acting and short-acting opioids for their effectiveness or adverse effects. (

EVIDENCE

fair) B) The relative and absolute contraindications to opioid use in chronic non-cancer pain must be evaluated including respiratory instability, acute psychiatric instability, uncontrolled suicide risk, active or history of alcohol or substance abuse, confirmed allergy to opioid agents, coadministration of drugs capable of inducing life-limiting drug interaction, concomitant use of benzodiazepines, active diversion of controlled substances, and concomitant use of heavy doses of central nervous system depressants. (

EVIDENCE

fair to limited) 6. A robust agreement which is followed by all parties is essential in initiating and maintaining opioid therapy as such agreements reduce overuse, misuse, abuse, and diversion. (

EVIDENCE

fair) 7. A) Once medical necessity is established, opioid therapy may be initiated with low doses and short-acting drugs with appropriate monitoring to provide effective relief and avoid side effects. (

EVIDENCE

fair for short-term effectiveness, limited for long-term effectiveness) B) Up to 40 mg of morphine equivalent is considered as low dose, 41 to 90 mg of morphine equivalent as a moderate dose, and greater than 91 mg of morphine equivalence as high dose. (

EVIDENCE

fair) C) In reference to long-acting opioids, titration must be carried out with caution and overdose and misuse must be avoided. (

EVIDENCE

good) 8. A) Methadone is recommended for use in late stages after failure of other opioid therapy and only by clinicians with specific training in the risks and uses. (

EVIDENCE

limited) B) Monitoring recommendation for methadone prescription is that an electrocardiogram should be obtained prior to initiation, at 30 days and yearly thereafter. (

EVIDENCE

fair) 9. In order to reduce prescription drug abuse and doctor shopping, adherence monitoring by UDT and PMDPs provide evidence that is essential to the identification of those patients who are non-compliant or abusing prescription drugs or illicit drugs. (

EVIDENCE

fair) 10. Constipation must be closely monitored and a bowel regimen be initiated as soon as deemed necessary. (

EVIDENCE

good) 11. Chronic opioid therapy may be continued, with continuous adherence monitoring, in well-selected populations, in conjunction with or after failure of other modalities of treatments with improvement in physical and functional status and minimal adverse effects. (

EVIDENCE

fair).

DISCLAIMER

The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."

An update of the systematic assessment of the diagnostic accuracy of lumbar facet joint nerve blocks

BACKGROUND

Lumbar facet joints are a well recognized source of low back pain and referred pain in the lower extremity in patients with chronic low back pain. Conventional clinical features and other non-invasive diagnostic modalities are unreliable in diagnosing lumbar zygapophysial joint pain. Controlled diagnostic studies with at least 80% pain relief as the criterion standard have shown the prevalence of lumbar facet joint pain to be 16% to 41% of patients with chronic low back pain without disc displacement or radiculitis, with a false-positive rate of 17% to 49% with a single diagnostic block.

STUDY DESIGN

A systematic review of the diagnostic accuracy of lumbar facet joint nerve blocks.

OBJECTIVE

To determine and update the diagnostic accuracy of lumbar facet joint nerve blocks in the assessment of chronic low back pain.

METHODS

A methodological quality assessment of included studies was performed using Quality Appraisal of Reliability Studies (QAREL). Only diagnostic accuracy studies meeting at least 50% of the designated inclusion criteria were utilized for analysis. Studies scoring less than 50% are presented descriptively and analyzed critically. The level of evidence was classified as good, fair, and limited or poor based on the quality of evidence developed by the United States Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to June 2012, and manual searches of the bibliographies of known primary and review articles.

OUTCOME MEASURES

Studies must have been performed utilizing controlled local anesthetic blocks. Pain relief was categorized as at least 50% pain relief from baseline pain and the ability to perform previously painful movements.

RESULTS

A total of 25 diagnostic accuracy studies were included. Of these, one study evaluated 50% to 74% relief as criterion standard with a single block with prevalence of 48%, 4 studies evaluated 75% to 100% relief as the criterion standard with a single block with a prevalence of 31% to 61%, 5 studies evaluated 50% to 74% relief as the criterion standard with controlled blocks with a prevalence of 15% to 61%, and 13 studies evaluated 75% to 100% relief as the criterion standard with controlled blocks with a prevalence of 25% to 45% in heterogenous populations. False-positive rates ranged from 17% to 66% relief and 27% to 49% with at least 75% relief as the criterion standard. Based on this evaluation, the evidence showed that there is good evidence for diagnostic facet joint nerve blocks with 75% to 100% pain relief as the criterion standard with dual blocks and fair evidence with 50% to 74% pain relief as the criterion standard with controlled diagnostic blocks; however, the evidence is poor with single diagnostic blocks of 50% to 74%, and limited for 75% or more pain relief as the criterion standard.

LIMITATIONS

The shortcomings of this systematic review of the accuracy of diagnostic lumbar facet joint nerve blocks include a paucity of literature and continued debate on an appropriate gold standard.

CONCLUSION

There is good evidence for diagnostic facet joint nerve blocks with 75% to 100% pain relief as the criterion standard with dual blocks, with fair evidence with 50% to 74% pain relief.

Systematic review of the therapeutic effectiveness of cervical facet joint interventions: an update

BACKGROUND

The prevalence of chronic, recurrent neck pain is approximately 15% of the adult general population. Controlled studies have supported the existence of cervical facet or zygapophysial joint pain in 36% to 67% of these patients, when disc herniation, radiculitis, and discogenic are not pathognomic. However, these studies also have shown false-positive results in 27% to 63% of the patients with a single diagnostic block. There is also a paucity of literature investigating therapeutic interventions of cervical facet joint pain.

STUDY DESIGN

Systematic review of therapeutic cervical facet joint interventions.

OBJECTIVE

To determine and update the clinical utility of therapeutic cervical facet joint interventions in the management of chronic neck pain.

METHODS

The available literature for utility of facet joint interventions in therapeutic management of cervical facet joint pain was reviewed. The quality assessment and clinical relevance criteria utilized were the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials and the criteria developed by the Newcastle-Ottawa Scale criteria for observational studies. The level of evidence was classified as good, fair, and limited or poor based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to June 2012, and manual searches of the bibliographies of known primary and review articles.

OUTCOME MEASURES

The primary outcome measure was pain relief (short-term relief = up to 6 months and long-term > 6 months). Secondary outcome measures were improvement in functional status, psychological status, return to work, and reduction in opioid intake.

RESULTS

In this systematic review, 32 manuscripts were considered for inclusion. For final analysis, 4 randomized trials and 6 observational studies met the inclusion criteria and were included in the evidence synthesis. Based on one randomized, sham-controlled, double-blind trial and 5 observational studies, the indicated evidence for cervical radiofrequency neurotomy is fair. Based on one randomized, double-blind, active-controlled trial and one prospective evaluation, the indicated evidence for cervical medial branch blocks is fair. Based on 2 randomized controlled trials, the evidence for cervical intraarticular injections is limited.

LIMITATIONS

Paucity of the overall published literature and specifically lack of literature for intraarticular cervical facet joint injections.

CONCLUSIONS

The indicated evidence for cervical radiofrequency neurotomy is fair. The indicated evidence for cervical medial branch blocks is fair. The indicated evidence for cervical intraarticular injections with local anesthetic and steroids is limited.

American Society of Interventional Pain Physicians (ASIPP) guidelines for responsible opioid prescribing in chronic non-cancer pain: Part I--evidence assessment

BACKGROUND

Opioid abuse has continued to increase at an alarming rate since the 1990 s. As documented by different medical specialties, medical boards, advocacy groups, and the Drug Enforcement Administration, available evidence suggests a wide variance in chronic opioid therapy of 90 days or longer in chronic non-cancer pain. Part 1 describes evidence assessment.

OBJECTIVES

The objectives of opioid guidelines as issued by the American Society of Interventional Pain Physicians (ASIPP) are to provide guidance for the use of opioids for the treatment of chronic non-cancer pain, to produce consistency in the application of an opioid philosophy among the many diverse groups involved, to improve the treatment of chronic non-cancer pain, and to reduce the incidence of abuse and drug diversion. The focus of these guidelines is to curtail the abuse of opioids without jeopardizing non-cancer pain management with opioids.

RESULTS

1) There is good evidence that non-medical use of opioids is extensive; one-third of chronic pain patients may not use prescribed opioids as prescribed or may abuse them, and illicit drug use is significantly higher in these patients. 2) There is good evidence that opioid prescriptions are increasing rapidly, as the majority of prescriptions are from non-pain physicians, many patients are on long-acting opioids, and many patients are provided with combinations of long-acting and short-acting opioids. 3) There is good evidence that the increased supply of opioids, use of high dose opioids, doctor shoppers, and patients with multiple comorbid factors contribute to the majority of the fatalities. 4) There is fair evidence that long-acting opioids and a combination of long-acting and short-acting opioids contribute to increasing fatalities and that even low-doses of 40 mg or 50 mg of daily morphine equivalent doses may be responsible for emergency room admissions with overdoses and deaths. 5) There is good evidence that approximately 60% of fatalities originate from opioids prescribed within the guidelines, with approximately 40% of fatalities occurring in 10% of drug abusers. 6) The short-term effectiveness of opioids is fair, whereas the long-term effectiveness of opioids is limited due to a lack of long-term (> 3 months) high quality studies, with fair evidence with no significant difference between long-acting and short-acting opioids. 7) Among the individual drugs, most opioids have fair evidence for short-term and limited evidence for long-term due to a lack of quality studies. 8) The evidence for the effectiveness and safety of chronic opioid therapy in the elderly for chronic non-cancer pain is fair for short-term and limited for long-term due to lack of high quality studies; limited in children and adolescents and patients with comorbid psychological disorders due to lack of quality studies; and the evidence is poor in pregnant women. 9) There is limited evidence for reliability and accuracy of screening tests for opioid abuse due to lack of high quality studies. 10) There is fair evidence to support the identification of patients who are non-compliant or abusing prescription drugs or illicit drugs through urine drug testing and prescription drug monitoring programs, both of which can reduce prescription drug abuse or doctor shopping.

DISCLAIMER

The guidelines are based on the best available evidence and do not constitute inflexible treatment recommendations. Due to the changing body of evidence, this document is not intended to be a "standard of care."

Effectiveness of cervical epidural injections in the management of chronic neck and upper extremity pain

BACKGROUND

Chronic persistent neck pain with or without upper extremity pain is common in the general adult population with prevalence of 48% for women and 38% for men, with persistent complaints in 22% of women and 16% of men. Multiple modalities of treatments are exploding in managing chronic neck pain along with increasing prevalence. However, there is a paucity of evidence for all modalities of treatments in managing chronic neck pain. Cervical epidural injections for managing chronic neck pain are one of the commonly performed interventions in the United States. However, the literature supporting cervical epidural steroids in managing chronic pain problems has been scant.

STUDY DESIGN

A systematic review of cervical interlaminar epidural injections for cervical disc herniation, cervical axial discogenic pain, cervical central stenosis, and cervical postsurgery syndrome.

OBJECTIVE

To evaluate the effect of cervical interlaminar epidural injections in managing various types of chronic neck and upper extremity pain emanating as a result of cervical spine pathology.

METHODS

The available literature on cervical interlaminar epidural injections in managing chronic neck and upper extremity pain were reviewed. The quality assessment and clinical relevance criteria utilized were the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials and the criteria developed by the Newcastle-Ottawa Scale criteria for observational studies. The level of evidence was classified as good, fair, and limited based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Data sources included relevant literature identified through searches of PubMed and EMBASE from 1966 to December 2011, and manual searches of the bibliographies of known primary and review articles.

OUTCOME MEASURES

The primary outcome measure was pain relief (short-term relief = up to 6 months and long-term > 6 months). Secondary outcome measures were improvement in functional status, psychological status, return to work, and reduction in opioid intake.

RESULTS

For this systematic review, 34 studies were identified. Of these, 24 studies were excluded and a total of 9 randomized trials, with 2 duplicate studies, met inclusion criteria for methodological quality assessment. For cervical disc herniation, the evidence is good for cervical epidural with local anesthetic and steroids; whereas, it was fair with local anesthetic only. For axial or discogenic pain, the evidence is fair for local anesthetic, with or without steroids. For spinal stenosis, the evidence is fair for local anesthetic, with or without steroids. For postsurgery syndrome, the evidence is fair for local anesthetic, with or without steroids.

LIMITATIONS

The limitations of this systematic review continue to be the paucity of literature.

CONCLUSION

The evidence is good for radiculitis secondary to disc herniation with local anesthetics and steroids, fair with local anesthetic only; whereas, it is fair for local anesthetics with or without steroids, for axial or discogenic pain, pain of central spinal stenosis, and pain of post surgery syndrome.

A critical review of the American Pain Society clinical practice guidelines for interventional techniques: part 2. Therapeutic interventions

BACKGROUND

Clinical guidelines are a constructive response to the reality that practicing physicians require assistance in assimilating and applying the exponentially expanding, often contradictory, body of medical knowledge. They attempt to define practices that meet the needs of most patients under most circumstances. Ideally, specific clinical recommendations contained within practice guidelines are systematically developed by expert panels who have access to all the available evidence, have an understanding of the clinical problem, and have clinical experience with the procedure being assessed, as well as knowledge of relevant research methods. The recent development of American Pain Society (APS) guidelines has created substantial controversy because of their perceived lack of objective analysis and recommendations perceived to be biased due to conflicts of interest.

OBJECTIVES

To formally and carefully assess the APS guidelines' evidence synthesis for low back pain for therapeutic interventions using the same methodology utilized by the APS authors. The interventions examined were therapeutic interventions for managing low back pain, including epidural injections, adhesiolysis, facet joint interventions, and spinal cord stimulation.

METHODS

A literature search by 2 authors was carried out utilizing appropriate databases from 1966 through July 2008. Articles in which conflicts arose were reviewed and mediated by a third author to arrive at a consensus. Selections of manuscripts and methodologic quality assessment was also performed by at least 2 authors utilizing the same criteria applied in the APS guidelines. The guideline reassessment process included the evaluation of individual studies and systematic reviews and their translation into practice recommendations.

RESULTS

The conclusions of APS and our critical assessment based on grading of good, fair, and poor, agreed that there is fair evidence for spinal cord stimulation in post lumbar surgery syndrome, and poor evidence for lumbar intraarticular facet joint injections, lumbar interlaminar epidural injections, caudal epidural steroids for conditions other than disc herniation or radiculitis, sacroiliac joint injections, intradiscal electrothermal therapy, endoscopic adhesiolysis, and intrathecal therapy. However, our assessment of APS guidelines for other interventional techniques, utilizing their own criteria, showed fair evidence for therapeutic lumbar facet joint nerve blocks, caudal epidural injections in disc herniation or radiculitis, percutaneous adhesiolysis in post lumbar surgery syndrome, radiofrequency neurotomy, and transforaminal epidural injections in radiculitis. Also it is illustrated that inclusion of latest literature will change the conclusions, with improved grading - caudal epidural, adhesiolysis, and lumbar facet joint nerve blocks from fair to good or poor to fair. The present critical assessment review illustrates that APS guidelines have utilized multiple studies inappropriately and have excluded appropriate studies. Our integrity assessment shows deep concerns that the APS guidelines illustrating significant methodologic failures which raise concerns about transparency, accountability, consistency, and independence.

CONCLUSION

The current reassessment, using appropriate methodology, shows evidence similar to APS guidelines for several procedures, but differs extensively from published APS guidelines for multiple other procedures including caudal epidural injections, lumbar facet joint nerve blocks, lumbar radiofrequency neurotomy, and percutaneous adhesiolysis.

Effectiveness of spinal endoscopic adhesiolysis in post lumbar surgery syndrome: a systematic review

BACKGROUND

Post lumbar surgery syndrome with persistent chronic low back and lower extremity pain is common in the United States. Epidural fibrosis may account for as much as 20% to 36% of all cases of failed back surgery syndrome (FBSS). Percutaneous adhesiolysis with a catheter or direct visualization of the spinal canal and the contents with an endoscope are techniques employed in resistant cases when patients fail to respond to conservative modalities of treatment, including fluoroscopically directed epidural injections. Some patients failing to respond to percutaneous adhesiolysis are candidates for spinal endoscopic adhesiolysis. However, literature evaluating the effectiveness of spinal endoscopic adhesiolysis is sparse and discussions continue about its effectiveness, utility, and complications.

STUDY DESIGN

A systematic review of the available literature.

OBJECTIVE

To evaluate the effectiveness and safety of spinal endoscopic adhesiolysis in the management of chronic low back and lower extremity pain in post surgical patients with chronic recalcitrant pain, non-responsive to conservative modalities of management and fluoroscopically directed epidural injections.

METHODS

A search of relevant resources (PubMed, EMBASE, and the Cochrane database) was accomplished and the resulting publications were examined based on the inclusion/exclusion criteria set forth. Randomized controlled trials and observational studies were included in the search. Two reviewers assessed the studies' methodologies and outcomes. Randomized clinical trials were assessed and scored based on the criteria established by the Cochrane methodological assessment criteria of randomized clinical trials and the observational studies were assessed and scored based on the Agency for Healthcare Research and Quality (AHRQ) criteria. Clinical relevance was evaluated utilizing Cochrane review criteria. Analysis was conducted using 5 levels of evidence, ranging from Level I to III, with 3 subcategories in Level II.

OUTCOME MEASURES

The primary outcome measure was pain relief (> or = 50%) in follow-up for at least 6 months. Pain relief for longer than 6 months was considered long-term and 6 months or less was considered short-term. The secondary outcome measures were functional and psychological status, return to work, patient satisfaction, and opioid intake.

RESULTS

Of the 13 studies considered for inclusion, one randomized trial and 5 observational studies met inclusion criteria for evidence synthesis based on the inclusion criteria and methodologic quality scores of 50 or more. The indicated level of evidence for endoscopic adhesiolysis is Level II-1 or II-2 evidence for short- and long-term relief based on the U.S. Preventive Services Task Force (USPSTF) criteria.

LIMITATIONS

There was a paucity of literature for randomized trials.

CONCLUSION

Spinal endoscopic adhesiolysis may be used as an effective treatment modality for chronic refractory low back pain and radiculopathy that is related to epidural adhesions.

Systematic assessment of diagnostic accuracy and therapeutic utility of lumbar facet joint interventions

BACKGROUND

Lumbar facet joints are a well recognized source of low back pain and referred pain in the lower extremity in patients with chronic low back pain. Conventional clinical features and other non-invasive diagnostic modalities are unreliable in diagnosing lumbar zygapophysial joint pain. Controlled diagnostic studies have shown the prevalence of lumbar facet joint pain in 27% to 40% of the patients with chronic low back pain without disc displacement or radiculitis, with a false-positive rate of 27% to 47% with a single diagnostic block.

STUDY DESIGN

A systematic review of diagnostic and therapeutic lumbar facet joint interventions.

OBJECTIVE

To determine the clinical utility of diagnostic and therapeutic lumbar facet joint interventions in managing chronic low back pain of facet joint origin.

METHODS

Review of the literature for clinical studies on efficacy and utility of facet joint interventions in diagnosing and managing facet joint pain was performed according to the Agency for Healthcare Research and Quality (AHRQ) criteria for diagnostic studies and observational studies and the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials. Data sources included relevant literature of the English language identified through searches of Medline and EMBASE from 1966 to December 2008 and manual searches of bibliographies of known primary and review articles. Analysis results were performed for diagnostic and therapeutic interventions separately.

LEVEL OF EVIDENCE

The level of evidence was defined as Level I, II, or III with 3 subcategories in Level II based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF) for therapeutic interventions.

OUTCOME MEASURES

For diagnostic interventions, studies must have been performed utilizing controlled local anesthetic blocks. Pain relief was categorized as at least 80% pain relief from baseline pain and ability to perform previously painful movements. For therapeutic interventions, the primary outcome measure was pain relief with secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake. For therapeutic interventions, short-term pain relief was defined as relief lasting 6 months or less and long-term relief as longer than 6 months.

RESULTS

Based on USPSTF criteria, evidence showed Level I or II-1 for diagnostic facet joint nerve blocks. Based on the review of included therapeutic studies, Level II-1 to II-2 evidence was indicated for lumbar facet joint nerve blocks with indicated level of evidence of Level II-2 to II-3 for lumbar radiofrequency neurotomy.

LIMITATIONS

The shortcoming of this systematic review of lumbar facet joint interventions is the paucity of published literature.

CONCLUSION

The evidence for diagnosis of lumbar facet joint pain with controlled local anesthetic blocks is Level I or II-1. The indicated level of evidence for therapeutic lumbar facet joint interventions is Level II-1 or II-2 for lumbar facet joint nerve blocks, Level II-2 or II-3 evidence for radiofrequency neurotomy, and Level III (limited) evidence for intraarticular injections.

Systematic review of diagnostic utility and therapeutic effectiveness of cervical facet joint interventions

BACKGROUND

Chronic, recurrent neck pain is common and is associated with high pain intensity and disability, which is seen in 14% of the adult general population. Controlled studies have supported the existence of cervical facet or zygapophysial joint pain in 36% to 67% of these patients. However, these studies also have shown false-positive results in 27% to 63% of the patients with a single diagnostic block. There is also a paucity of literature investigating therapeutic interventions of cervical facet joint pain.

STUDY DESIGN

A systematic review of cervical facet joint interventions.

OBJECTIVE

To evaluate the accuracy of diagnostic facet joint nerve blocks and the effectiveness of cervical facet joint interventions.

METHODS

Medical databases and journals were searched to locate all relevant literature from 1966 through December 2008 in the English language. A review of the literature of the utility of facet joint interventions in diagnosing and managing facet joint pain was performed according to the Agency for Healthcare Research and Quality (AHRQ) criteria for diagnostic studies and observational studies and the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials.

LEVEL OF EVIDENCE

The level of evidence was defined as Level I, II, or III based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF).

OUTCOME MEASURES

For diagnostic interventions, studies must have been performed utilizing controlled local anesthetic blocks which achieve at minimum 80% relief of pain and the ability to perform previously painful movements. For therapeutic interventions, the primary outcome measure was pain relief (short-term relief up to 6 months and long-term relief greater than 6 months) with secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake.

RESULTS

Based on the utilization of controlled comparative local anesthetic blocks, the evidence for the diagnosis of cervical facet joint pain is Level I or II-1. The indicated evidence for therapeutic cervical medial branch blocks is Level II-1. The indicated evidence for radiofrequency neurotomy in the cervical spine is Level II-1 or II-2, whereas the evidence is lacking for intraarticular injections.

LIMITATIONS

A systematic review of cervical facet joint interventions is hindered by the paucity of published literature and lack of literature for intraarticular cervical facet joint injections.

CONCLUSIONS

The evidence for diagnosis of cervical facet joint pain with controlled comparative local anesthetic blocks is Level I or II-1. The indicated evidence for therapeutic facet joint interventions is Level II-1 for medial branch blocks, and Level II-1 or II-2 for radiofrequency neurotomy.

Intradiscal electrothermal annuloplasty therapy: a case series study leading to new considerations

OBJECTIVE

To evaluate outcomes of intradiscal electrothermal annuloplasty (IDEA) therapy in the treatment of chronic discogenic low back pain in consecutive IDEA patients treated at a rural pain management clinic.

STUDY DESIGN

An observational case series study design was applied to consecutive IDEA patients qualifying under the inclusion and exclusion criteria. Patient assessment of pain and disability were performed at baseline and 6 weeks, 3, 6, 12, and 24 months post-IDEA.

METHODS

Selected patients underwent IDEA for an average of 15 minutes at a temperature of 90 degrees C. Analyses of outcomes included Visual Analog Scale (VAS) assessments of levels of pain, and Roland Morris Disability Questionnaire (RMDQ) assessments of functional capacity at pretreatment, and 6 weeks, 3, 6, 12, and 18 months post-treatment time points.

RESULTS

At 6 months post-IDEA treatment, patients (n=51) demonstrated statistically significant improvement (P < 0.001) as measured by a mean change of over 20 points from the pretreatment score on the RMDQ. At 1 year, post data remained significant in the 33 patients who had achieved this time point. VAS pain data were also statistically significant at 6 months (P = 0.023). Analysis of patient profiles revealed that statistically significant improvement of pain and functional capacity was strongly associated with female gender and age (range of 18-45 years), and that statistically significant improvement was not sustained in males beyond the 3-6 month point. These data support the outcomes reported in the few existing observational studies to date. Of 86 patients receiving IDEA therapy, 73 provided RMDQ data at baseline and at 3 months or later and were included in the analyses. Some patients were lost to follow-up at later time points.

CONCLUSIONS

These data show favorable outcomes after IDEA therapy, and suggest that women may experience more improvement than men, particularly with regard to perceived disability improvements. Data suggest that greater improvement in IDEA outcomes may be achieved by profiling the characteristics of patients who achieve the optimal long-term outcomes following treatment and should be considered during evaluation of patient eligibility for IDEA.

An implantable drug delivery system (IDDS) for refractory cancer pain provides sustained pain control, less drug-related toxicity, and possibly better survival compared with comprehensive medical management (CMM)

BACKGROUND

The randomized clinical trial of implantable drug delivery systems (IDDS) plus comprehensive medical management (CMM) versus CMM alone showed better clinical success at 4 weeks for IDDS patients. This 'as treated' analysis assessed if improvements in pain control, drug toxicity and survival were maintained over time.

PATIENTS AND METHODS

We compared those who received IDDS with those who did not receive IDDS (non-IDDS). All patients had Visual Analogue Scores (VAS) for pain > or =5/10 on at least 200 mg morphine or equivalent daily.

RESULTS

At 4 weeks, 46 of 52 (88.5%) IDDS patients achieved clinical success compared with 65 of 91 (71.4%; P=0.02) non-IDDS patients, and more often achieved > or =20% reduction in both pain VAS and toxicity [35 of 52 (67.3%) versus 33 of 91 patients (36.3%); P=0.0003]. By 12 weeks, 47 of 57 (82.5%) IDDS patients had clinical success compared with 35 of 45 (77.8%; P=0.55) non-IDDS patients, and more often had a > or =20% reduction in both pain VAS and toxicity [33 of 57 (57.9%) versus 15 of 45 patients (33.3%); P=0.01]. At 12 weeks the IDDS VAS pain scores decreased from 7.81 to 3.89 (47% reduction) compared with 7.21 to 4.53 for non-IDDS patients (42% reduction; P=0.23). The 12 week drug toxicity scores for IDDS patients decreased from 6.68 to 2.30 (66% reduction), and for non-IDDS patients from 6.73 to 4.13 (37% reduction; P=0.01). All individual drug toxicities improved with IDDS at both 4 and 12 weeks. At 6 months, only 32% of the group randomized to CMM and who did not cross over to IDDS were alive, compared with 52%-59% for patients in those groups who received IDDS.

CONCLUSIONS

IDDS improved clinical success, reduced pain scores, relieved most toxicity of pain control drugs, and was associated with increased survival for the duration of this 6 month trial.

Intrathecal ziconotide in the treatment of refractory pain in patients with cancer or AIDS: a randomized controlled trial

CONTEXT

Ziconotide (formerly SNX-111) selectively blocks N-type voltage-sensitive calcium channels and may be effective in patients with pain that is refractory to opioid therapy or those with intolerable opioid-related adverse effects.

OBJECTIVE

To assess the safety and efficacy of intrathecal ziconotide in patients with pain that is refractory to conventional treatment.

DESIGN, SETTING, AND PATIENTS

Double-blind, placebo-controlled, randomized trial conducted from March 12, 1996, to July 11, 1998, at 32 study centers in the United States, Australia, and the Netherlands. Patients were 111 individuals ages 24 to 85 years with cancer or AIDS and a mean Visual Analog Scale of Pain Intensity (VASPI) score of 50 mm or greater. Patients were randomly assigned in a 2:1 ratio to receive ziconotide or placebo treatment.

INTERVENTIONS

Intrathecal ziconotide was titrated over 5 to 6 days, followed by a 5-day maintenance phase for responders and crossover of nonresponders to the opposite treatment group.

MAIN OUTCOME MEASURE

Mean percentage change in VASPI score from baseline to the end of the initial titration period.

RESULTS

Of the evaluable population, 67 (98.5%) of 68 patients receiving ziconotide and 38 (95%) of 40 patients receiving placebo were taking opioids at baseline (median morphine equivalent dosage of 300 mg/d for the ziconotide group and 600 mg/d for the placebo group; P =.63, based on mean values), and 36 had used intrathecal morphine. Mean (SD) VASPI scores were 73.6 (1.8) mm in the ziconotide group and 77.9 (2.3) mm in the placebo group (P =.18). Mean VASPI scores improved 53.1% (95% confidence interval [CI], 44.0%-62.2%) in the ziconotide group and 18.1% (95% CI, 4.8%-31.4%) in the placebo group (P<.001), with no loss of efficacy of ziconotide in the maintenance phase. Pain relief was moderate to complete in 52.9% of patients in the ziconotide group compared with 17.5% in the placebo group (P<.001). Five patients receiving ziconotide achieved complete pain relief, and 50.0% of patients receiving ziconotide responded to therapy compared with 17.5% of those receiving placebo (P =.001).

CONCLUSION

Intrathecal ziconotide provided clinically and statistically significant analgesia in patients with pain from cancer or AIDS.

Randomized clinical trial of an implantable drug delivery system compared with comprehensive medical management for refractory cancer pain: impact on pain, drug-related toxicity, and survival

PURPOSE

Implantable intrathecal drug delivery systems (IDDSs) have been used to manage refractory cancer pain, but there are no randomized clinical trial (RCT) data comparing them with comprehensive medical management (CMM).

PATIENTS AND METHODS

We enrolled 202 patients on an RCT of CMM versus IDDS plus CMM. Entry criteria included unrelieved pain (visual analog scale [VAS] pain scores >/= 5 on a 0 to 10 scale). Clinical success was defined as >/= 20% reduction in VAS scores, or equal scores with >/= 20% reduction in toxicity. The main outcome measure was pain control combined with change of toxicity, as measured by the National Cancer Institute Common Toxicity Criteria, 4 weeks after randomization.

RESULTS

Sixty of 71 IDDS patients (84.5%) achieved clinical success compared with 51 of 72 CMM patients (70.8%, P =.05). IDDS patients more often achieved >/= 20% reduction in both pain VAS and toxicity (57.7% [41 of 71] v 37.5% [27 of 72], P =.02). The mean CMM VAS score fell from 7.81 to 4.76 (39% reduction); for the IDDS group, the scores fell from 7.57 to 3.67 (52% reduction, P =.055). The mean CMM toxicity scores fell from 6.36 to 5.27 (17% reduction); for the IDDS group, the toxicity scores fell from 7.22 to 3.59 (50% reduction, P =.004). The IDDS group had significant reductions in fatigue and depressed level of consciousness (P <.05). IDDS patients had improved survival, with 53.9% alive at 6 months compared with 37.2% of the CMM group (P =.06).

CONCLUSION

IDDSs improved clinical success in pain control, reduced pain, significantly relieved common drug toxicities, and improved survival in patients with refractory cancer pain.

Measurement of IgM responses to a subunit influenza A vaccine by sucrose-gradient centrifugation and membrane-filtration enzyme immunoassays

IgM responses to a deoxycholate-split influenza vaccine containing the surface antigens of the H3N2 virus A/Philippines/2/82 were studied in five volunteers, three of whom were seronegative by haemagglutination inhibition (HI) tests. Responses were measured by a sucrose-gradient centrifugation technique, in which IgM-specific HI activity was computed as a proportion of total IgM and IgG-specific HI activity, and by a membrane filtration-enzyme immunoassay (MF-EIA). Responses could be detected in all volunteers when measured by sucrose-gradient centrifugation within 1-2 weeks, and the IgM induced was 5-40% of total HI-specific activity. The response was also observed in the presence of low levels of pre-existing antibody. Levels of IgM antibody, when measured by MF-EIA, could be easily detected in two of the volunteers, while those of two others were very low and there was no response in a fifth. No biphasic virus-specific response to vaccination, involving first IgM and then IgG, could be measured by either technique. From these studies, the sucrose-gradient fractionation technique appears to be the more sensitive procedure.

An improved membrane-filtration enzyme immunoassay for the rapid serological diagnosis of viral infections

A one-step modification of the membrane-filtration enzyme immunoassay (MF EIA) (Barnett et al., J. Clin. Microbiol., 23:385-399, 1987), for estimation of virus-specific antibody is described. The modified MF EIA allowed serum, antigen and enzyme-conjugated anti-globulin to be incubated together in membrane-based 96-well plates to enable the formation of immune complexes in solution at 37 degrees C. The assay required only 45 min for completion and polyethylene glycol was shown to be an essential component in reaction mixtures for IgG assays to enhance immune complex formation. The modified MF EIA was as sensitive as the previous two-step method for monitoring responses to influenza vaccine, and control antigen backgrounds were significantly reduced. The one-step procedure was also shown to be suitable for the rapid serodiagnosis of naturally acquired influenza A and B infections. However, MF EIA detected cross-reactive H1N1 responses in 57.7% of naturally-acquired H3N2 infections, suggesting that responses to common internal antigens were being measured. Cross-reactive responses to influenza A viruses could not be detected in volunteers receiving subunit vaccines.

Freeze-drying of respiratory syncytial viruses for transportation and storage

The stabilities of eight strains of respiratory syncytial virus were compared after the strains were freeze-dried in the presence and absence of the stabilizer SPGA, which contains 218 mM sucrose, 7.1 mM dipotassium hydrogen phosphate, 3.76 mM potassium dihydrogen phosphate, 4.9 mM sodium glutamate, and 1% (wt/vol) bovine albumin. Strains freeze-dried in the presence of SPGA showed only small-to-negligible losses at 4 degrees C and losses of approximately 2.0 log10 infectious units at 25 degrees C when held for 45 weeks. Losses at 37 degrees C for one strain were approximately 10-fold greater when the strain was freeze-dried in the absence of SPGA. These results indicate that respiratory syncytial virus strains freeze-dried in the presence of a suitable stabilizer can be transported as unrefrigerated samples without undue losses in infectivity.

Age-related responses to influenza vaccination in the Newcastle region during 1983 and 1984

A study was carried out in Newcastle to assess responses to influenza vaccines in elderly nursing home patients and in younger adults during 1983 and 1984. The decision to vaccinate the elderly subjects was made by their general practitioners. A concurrent randomized placebo-controlled trial of the same vaccine was performed in young adult volunteers. Elderly subjects generally possessed higher levels of pre-existing antibody to the influenzal haemagglutinins that were present in the vaccines than did younger subjects. The highest levels were observed in the 52-63 years' age group. Younger subjects showed significantly greater responses to vaccines compared with elderly subjects (P less than 0.05). Peak responses were noted in the 16-24 years' age group. Of a total of 326 elderly subjects (70% of whom had been vaccinated), six participants, two of whom had been vaccinated, contracted laboratory-proven influenza during 1983. Only one unvaccinated subject of a total of 365 subjects (50% of whom had been vaccinated) contracted influenza during 1984. In both years illness was produced by strain A/Philippines/2/82.

Membrane filtration enzyme immunoassay, a novel, rapid method for measurement of virus-specific immunoglobulins G and M and detection of viral antigens

A novel membrane filtration enzyme immunoassay (MF EIA) is described in which virus-antibody complexes formed are trapped onto the surface of membranes with low protein-binding affinity by vacuum filtration. Class-specific immunoglobulin G (IgG) or IgM antibody was measured by adding enzyme-conjugated antiimmunoglobulin and incubating prior to the final wash and addition of enzyme substrate. Influenza A virus-specific IgG antibodies measured by MF EIA showed similar sensitivity for detecting seroconversion in volunteers administered influenza virus subunit vaccines and subtype specificity comparable to that observed by the hemagglutination inhibition technique. Cytomegalovirus-specific IgG antibodies measured by MF EIA with commercially available complement fixation antigens gave results similar to those of conventional enzyme-linked immunosorbent assay and complement fixation tests. The MF EIA method is also suitable for detection of rotavirus antigen in feces.

Evaluation of chicken kidney and chicken embryo kidney cultures for the large-scale growth of attenuated influenza virus master strain A/Ann/Arbor/6/60-ca

Primary chicken kidney (CK) and chicken embryo kidney (CEK) cells were evaluated as possible substrates for growth of the cold-adapted attenuated influenza vaccine master strain A/Ann Arbor/6/60 (A/AA/6/60-ca). Yields of 10(6)-10(7) TCID50 per ml of culture fluid were obtained in either cell type. Yields from the human diploid strain MRC-5 were approximately 100-fold less. More reproducible cultures were obtained from CEK cells, using an overnight trypsinization step at 4 degrees C, than from CK cells. Comparable yields per embryo were obtained from CEK cells grown in roller cultures to those grown on the surface of microcarriers. These yields were less than those obtained from the allantoic fluids of whole embryos. Frozen storage of CEK or CK cells, after primary trypsinization, dispersal from a cultured CK primary monolayer or culture on microcarriers, was unsuccessful. The cold-adapted phenotype of A/AA/6/60-ca was retained after growth in CEK cultures and no differences in immunogenicity were detectable in mice between CEK- and allantoic-grown virus. Allantoic-grown preparations of A/AA/6/60-ca contained a lower protein concentration per infectious unit than those grown in CEK.

Responses to one or two doses of a deoxycholate subunit influenza vaccine in a primed population

A trial with a trivalent influenza subunit vaccine prepared with sodium deoxycholate was carried out in 88 volunteers between May and November 1981. Each haemagglutinin antigen was present at 7 micrograms per dose. Fourfold or greater haemagglutination inhibition antibody (HI) responses to the H1N1 virus A/Brazil/11/78 occurred in 70% of volunteers following a single dose. For the H3N2 virus A/Bangkok/1/79 and B/Singapore/222/79 these figures were 52 and 11%, respectively. No increase in the antibody titre was noted to any of the antigens following a second vaccination dose. Antibody levels remained relatively constant six months after vaccination. A response to B/Singapore/222/79, comparable with the HI response for the influenza A antigens, was noted when serum titres were estimated by a plaque reduction procedure. No neuraminidase inhibition antibody could be detected in response to either A/Brazil/11/78 or A/Bangkok/1/79. No reactions specifically attributable to the vaccine occurred after either injection. A lower HI response to A/Brazil/11/78 was noted in volunteers 52 years of age and older, who also showed less evidence of earlier priming to this virus. Levels of nasal wash neutralizing antibodies to A/Brazil/11/78 were proportional to those detected in sera by HI tests, but were present in smaller amounts.

The binding of divalent cations to myosin

Centrifuge transport, equilibrium dialysis, and electron paramagnetic resonance studies on the binding of Mn2+ to myosin revealed two sets of noninteracting binding sites which are characterized at low ionic strength (0.016 M KCl) by affinity constants of 10(6) M-1 (Class I) and 10(3) M-1 (Class II), respectively. At 0.6 M KCl concentration, the affinity of Mn2+ for both sets of sites is reduced. The maximum number of binding sites is 2 for the high affinity and 20 to 25 for the low affinity set. Other divalent metal ions displace Mn2+ from the high affinity sites in the following order of effectiveness: Ca greater than Mg = Zn = Co greater than Sr greater than Ni. The inhibitory effects of Mg2+ and Ca2+ upon the Mn2+ binding are competitive with inhibitor constants of 0.75 to 1 mM which is similar to that of the low affinity divalent metal ion binding sites. Exposure of myosin to 37 degrees partially inhibits Mn2+ binding to Class I parallel with inhibition of ATPase activity. The binding of Mn2+ to the high affinity binding sites is not significantly influenced by ADP or PPi, although Mn2+ increases the affinity of ADP binding to myosin at high ionic strength.