The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Altered expression of the ToxR-regulated porins OmpU and OmpT diminishes Vibrio cholerae bile resistance, virulence factor expression, and intestinal colonization

The transmembrane transcriptional activators ToxR and TcpP modulate expression of Vibrio cholerae virulence factors by exerting control over toxT, which encodes the cytoplasmic transcriptional activator of the ctx, tcp, and acf virulence genes. However, ToxR, independently of TcpP and ToxT, activates and represses transcription of the genes encoding two outer-membrane porins, OmpU and OmpT. To determine the role of ToxR-dependent porin regulation in V. cholerae pathogenesis, the ToxR-activated ompU promoter was used to drive ompT transcription in a strain lacking OmpU. Likewise, the ToxR-repressed ompT promoter was used to drive ompU transcription in a strain lacking both ToxR and OmpT. This strategy allowed the generation of a toxR(+) strain that expresses OmpT in place of OmpU, and a toxR(-) strain that expresses OmpU in place of OmpT. Growth rates in the presence of bile salts and other anionic detergents were retarded for the toxR(+) V. cholerae expressing OmpT in place of OmpU, but increased in toxR(-) V. cholerae expressing OmpU in place of OmpT. Additionally, the toxR(+) V. cholerae expressing OmpT in place of OmpU expressed less cholera toxin and toxin-coregulated pilus, and this effect was shown to be caused by reduced toxT transcription in this strain. Finally, the toxR(+) V. cholerae expressing OmpT in place of OmpU was approximately 100-fold reduced in its ability to colonize the infant-mouse intestine. Our results indicate that ToxR-dependent modulation of the outer membrane porins OmpU and OmpT is critical for V. cholerae bile resistance, virulence factor expression, and intestinal colonization.

Caring for patients with pain during the COVID-19 pandemic: consensus recommendations from an international expert panel

Chronic pain causes significant suffering, limitation of daily activities and reduced quality of life. Infection from COVID-19 is responsible for an ongoing pandemic that causes severe acute respiratory syndrome, leading to systemic complications and death. Led by the World Health Organization, healthcare systems across the world are engaged in limiting the spread of infection. As a result, all elective surgical procedures, outpatient procedures and patient visits, including pain management services, have been postponed or cancelled. This has affected the care of chronic pain patients. Most are elderly with multiple comorbidities, which puts them at risk of COVID-19 infection. Important considerations that need to be recognised during this pandemic for chronic pain patients include: ensuring continuity of care and pain medications, especially opioids; use of telemedicine; maintaining biopsychosocial management; use of anti-inflammatory drugs; use of steroids; and prioritising necessary procedural visits. There are no guidelines to inform physicians and healthcare providers engaged in caring for patients with pain during this period of crisis. We assembled an expert panel of pain physicians, psychologists and researchers from North America and Europe to formulate recommendations to guide practice. As the COVID-19 situation continues to evolve rapidly, these recommendations are based on the best available evidence and expert opinion at this present time and may need adapting to local workplace policies.

The appropriate use of neurostimulation: avoidance and treatment of complications of neurostimulation therapies for the treatment of chronic pain. Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The International Neuromodulation Society (INS) has determined that there is a need for guidance regarding safety and risk reduction for implantable neurostimulation devices. The INS convened an international committee of experts in the field to explore the evidence and clinical experience regarding safety, risks, and steps to risk reduction to improve outcomes.

METHODS

The Neuromodulation Appropriateness Consensus Committee (NACC) reviewed the world literature in English by searching MEDLINE, PubMed, and Google Scholar to evaluate the evidence for ways to reduce risks of neurostimulation therapies. This evidence, obtained from the relevant literature, and clinical experience obtained from the convened consensus panel were used to make final recommendations on improving safety and reducing risks.

RESULTS

The NACC determined that the ability to reduce risk associated with the use of neurostimulation devices is a valuable goal and possible with best practice. The NACC has recommended several practice modifications that will lead to improved care. The NACC also sets out the minimum training standards necessary to become an implanting physician.

CONCLUSIONS

The NACC has identified the possibility of improving patient care and safety through practice modification. We recommend that all implanting physicians review this guidance and consider adapting their practice accordingly.

The virulence regulatory protein ToxR mediates enhanced bile resistance in Vibrio cholerae and other pathogenic Vibrio species

The transmembrane regulatory protein ToxR is required for expression of virulence factors in the human diarrheal pathogen Vibrio cholerae, including cholera toxin (CT) and the toxin coregulated pilus (TCP). ToxR is necessary for transcription of the gene encoding a second regulatory protein, ToxT, which is the direct transcriptional activator of CT and TCP genes. However, ToxR, independent of ToxT, directly activates and represses transcription of the outer membrane porins OmpU and OmpT, respectively. The genes encoding TCP and CT (and including ToxT) lie on horizontally acquired genetic elements, while the toxR, ompU, and ompT genes are apparently in the ancestral Vibrio chromosome. The contribution of ToxR-dependent modulation of outer membrane porins to cholera pathogenesis has remained unknown. We demonstrate that ToxR mediates enhanced bile resistance in a ToxT-independent manner. In both classical and El Tor biotypes of V. cholerae, a toxR mutant strain has a reduced minimum bactericidal concentration (MBC) of bile, the bile component deoxycholate (DC), and the anionic detergent sodium dodecyl sulfate (SDS) compared to both wild-type and toxT mutant strains. Classical and El Tor toxR mutant strains also exhibit reduced growth rates at subinhibitory concentrations of DC and SDS. Growth of either V. cholerae biotype in subinhibitory concentrations of bile or DC induces increased ToxR-dependent production of a major 38-kDa outer membrane protein, which was confirmed to be OmpU by Western blot. Measurement of transcription of a ompUp-lacZ fusion in both biotypes reveals stimulation (about two- to threefold) of ToxR-dependent ompU transcription by the presence of bile or DC, suggesting that ToxR may respond to the presence of bile. The toxR mutant strains of three additional human intestinal pathogenic Vibrio species, V. mimicus, V. fluvialis, and V. parahaemolyticus, display lower MBCs of bile, DC, and SDS and have altered outer membrane protein profiles compared to the parental wild-type strains. Our results demonstrate a conserved role for ToxR in the modulation of outer membrane proteins and bile resistance of pathogenic Vibrio species and suggest that these ToxR-dependent outer membrane proteins may mediate enhanced resistance to bile. We speculate that ToxR-mediated bile resistance was an early step in the evolution of V. cholerae as an intestinal pathogen.

DNA adenine methylase is essential for viability and plays a role in the pathogenesis of Yersinia pseudotuberculosis and Vibrio cholerae

Salmonella strains that lack or overproduce DNA adenine methylase (Dam) elicit a protective immune response to different Salmonella species. To generate vaccines against other bacterial pathogens, the dam genes of Yersinia pseudotuberculosis and Vibrio cholerae were disrupted but found to be essential for viability. Overproduction of Dam significantly attenuated the virulence of these two pathogens, leading to, in Yersinia, the ectopic secretion of virulence proteins (Yersinia outer proteins) and a fully protective immune response in vaccinated hosts. Dysregulation of Dam activity may provide a means for the development of vaccines against varied bacterial pathogens.

The Neuromodulation Appropriateness Consensus Committee on Best Practices for Dorsal Root Ganglion Stimulation

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) is dedicated to improving the safety and efficacy of neuromodulation and thus improving the lives of patients undergoing neuromodulation therapies. With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion (DRG) stimulation has significantly improved the treatment of complex regional pain syndrome (CRPS), among other conditions. Through funding and organizational leadership by the International Neuromodulation Society (INS), the NACC reconvened to develop the best practices consensus document for the selection, implantation and use of DRG stimulation for the treatment of chronic pain syndromes.

METHODS

The NACC performed a comprehensive literature search of articles about DRG published from 1995 through June, 2017. A total of 2538 article abstracts were then reviewed, and selected articles graded for strength of evidence based on scoring criteria established by the US Preventive Services Task Force. Graded evidence was considered along with clinical experience to create the best practices consensus and recommendations.

RESULTS

The NACC achieved consensus based on peer-reviewed literature and experience to create consensus points to improve patient selection, guide surgical methods, improve post-operative care, and make recommendations for management of patients treated with DRG stimulation.

CONCLUSION

The NACC recommendations are intended to improve patient care in the use of this evolving therapy for chronic pain. Clinicians who choose to follow these recommendations may improve outcomes.

Analysis of human immunoglobulin-degrading cysteine proteinases of Trichomonas vaginalis

Trichomonas vaginalis is a protozoan parasite that causes a widely distributed sexually transmitted disease (STD). Since immunoglobulin G (IgG) antibodies to specific trichomonad immunogens are found in serum and vaginal washes (VWs) from patients with trichomoniasis, a potential mechanism of immune evasion by this parasite might be the ability of T. vaginalis proteinases to degrade human immunoglobulins (Igs). Incubation of human IgG with lysates of T. vaginalis organisms resulted in time- and concentration-dependent degradation of the heavy chain. Secretory IgA was degraded similarly. Inhibitors of cysteine proteinases, when added to trichomonal lysates, abolished IgG and IgA degradation, while EDTA, a metalloproteinase inhibitor, did not. Substrate-gel electrophoresis with human IgG, IgM, or IgA copolymerized with acrylamide revealed several distinct cysteine proteinases in both lysates and culture supernatants from logarithmically growing parasites that degraded all classes of human antibodies. Trichomonal lysates and supernatants of numerous isolates tested all had Ig-degrading activity. Finally, proteolytic activity against IgG was detected in most (26 of 33; 78%) VWs from patients with trichomoniasis. In contrast, 18 of 28 (65%) VWs from women without trichomoniasis or from patients infected with other STDs had no detectable proteinases when tested in an identical manner. The other 10 of these 28 VWs (35%) had smaller amounts of detectable Ig-degrading proteinases. These differences in Ig-degrading proteinase activity between patients with and without trichomoniasis, regardless of coinfecting STDs, were statistically significant (P = 0.001). These results illustrate that T. vaginalis is capable of degrading human Igs.

Twelve-Month results from multicenter, open-label, randomized controlled clinical trial comparing differential target multiplexed spinal cord stimulation and traditional spinal cord stimulation in subjects with chronic intractable back pain and leg pain

Background

Spinal cord stimulation (SCS) is a well‐established treatment for chronic intractable pain of the trunk and/or limbs; however, low back pain (LBP) is difficult to treat using traditional SCS. Differential Target Multiplexed spinal cord stimulation (DTM SCS) is an advanced approach inspired from animal studies demonstrating improved pain‐related behavior and pain‐relevant biological processes.

Objective

The purpose of this study was to compare the effectiveness of DTM SCS and traditional SCS in treating chronic LBP and leg pain (LP).

Methods

This prospective, postmarket randomized controlled trial compared DTM SCS to traditional SCS in patients with chronic LBP and LP. Primary end point was LBP responder rate (percentage of subjects with ≥ 50% relief) at 3 months. Noninferiority and superiority were assessed. Other outcomes included mean change in back and leg pain, responder rates, disability, global health, satisfaction, and safety profile throughout the 12‐month follow‐up.

Results

One hundred twenty‐eight subjects were randomized across 12 centers (67 DTM SCS and 61 traditional SCS). Of the 94 patients implanted, 46 subjects in each group completed the 3‐month assessment. LBP responder rate of 80.1% with DTM SCS was superior to 51.2% with traditional SCS (p = 0.0010). Mean LBP reduction (5.36 cm) with DTM SCS was greater than reduction (3.37 cm) with traditional SCS (p < 0.0001). These results were sustained at 6 months and 12 months. Safety profiles were similar between treatment groups.

Conclusion

Superiority of DTM SCS compared with traditional SCS for chronic LBP was demonstrated. Clinical improvements provided by DTM SCS were sustained over 12 months and are expected to significantly impact the management of chronic LBP.

Characterization of the role of the ToxR-modulated outer membrane porins OmpU and OmpT in Vibrio cholerae virulence

ToxR, the transmembrane regulatory protein required for expression of virulence factors in the human diarrheal pathogen Vibrio cholerae, directly activates and represses the transcription of two outer membrane porins, OmpU and OmpT, respectively. In an attempt to dissect the role of the OmpU and OmpT porins in viability and virulence factor expression, in-frame chromosomal deletions were constructed in the coding sequences of ompU and ompT of V. cholerae. Two separate deletions were introduced into ompU; the first (small) deletion, Delta ompU1, removed the coding sequence for 84 internal amino acids (aa), while the second (large) deletion, Delta ompU2, removed the coding sequence for the entire amino-terminal 274 aa. The Delta ompU1 strain had a growth defect that could not be complemented by episomal expression of full-length ompU. In contrast, a strain with Delta ompU2 displayed wild-type growth kinetics in rich media, suggesting that this is the true phenotype of a strain lacking OmpU and that the truncated OmpU protein, rather than the absence of OmpU, may be the cause for the Delta ompU1 phenotype. A large deletion removing the coding sequence for the entire N-terminal 273 aa of OmpT (Delta ompT) was also constructed in wild-type as well as Delta toxR and Delta ompU2 strains, and these strains displayed wild-type growth kinetics in rich media. However, the Delta ompU2 strain was deficient for growth in deoxycholate compared to wild-type, Delta ompT, and Delta ompU2 Delta ompT strains, reinforcing a positive role for the OmpU porin and a negative role for the OmpT porin in V. cholerae resistance to anionic detergents. The Delta ompU2, Delta ompT, and Delta ompU2 Delta ompT strains exhibited wild-type levels of in vitro virulence factor expression and resistance to polymyxin B and serum and in vivo colonization levels similar to a wild-type strain in the infant mouse intestine. Our results demonstrate that (i) OmpU and OmpT are not essential proteins, as was previously thought; (ii) these porins contribute to V. cholerae resistance to anionic detergents; and (iii) OmpU and OmpT are not essential for virulence factor expression in vitro or intestinal colonization in vivo.

Identification and characterization of human surfactant protein A binding protein of Mycoplasma pneumoniae

Mycoplasma pneumoniae infections represent a major primary cause of human respiratory diseases, exacerbate other respiratory disorders, and are associated with extrapulmonary pathologies. Cytadherence is a critical step in mycoplasma colonization, aided by a network of mycoplasma adhesins and cytadherence accessory proteins which mediate binding to host cell receptors. Furthermore, the respiratory mucosa is enriched with extracellular matrix components, including surfactant proteins, fibronectin, and mucin, which provide additional in vivo targets for mycoplasma parasitism. In this study we describe interactions between M. pneumoniae and human surfactant protein-A (hSP-A). Initially, we found that viable M. pneumoniae cells bound to immobilized hSP-A in a dose- and calcium (Ca(2+))-dependent manner. Mild trypsin treatment of intact mycoplasmas reduced binding markedly (80 to 90%) implicating a surface-associated mycoplasma protein(s). Using hSP-A-coupled Sepharose affinity chromatography and polyacrylamide gel electrophoresis, we identified a 65-kDa hSP-A binding protein of M. pneumoniae. The presence of Ca(2+) enhanced binding of the 65-kDa protein to hSP-A, which was reduced by the divalent cation-chelating agent, EDTA. The 65-kDa hSP-A binding protein of M. pneumoniae was identified by sequence analysis as a novel protein (MPN372) possessing a putative S1-like subunit of pertussis toxin at the amino terminus (amino acids 1 to 226), with the remaining amino acids (227 to 591) exhibiting no homology with other subunits of pertussis toxin, other known toxins, or any reported proteins. Recombinant MPN372 (MPN372) bound to hSP-A in a dose-dependent manner, which was markedly reduced by preincubation with mouse recombinant MPN372 antisera. Also, adherence of viable M. pneumoniae cells to hSP-A was inhibited by recombinant MPN372 antisera, demonstrating that MPN372, a previously designated hypothetical protein, is surface exposed and mediates mycoplasma attachment to hSP-A.

Iron mediates Trichomonas vaginalis resistance to complement lysis

Trichomonas vaginalis, a sexually transmitted disease agent in humans, is readily lysed by activation of the alternative complement pathway. The parasite became resistant following growth in medium supplemented by iron compared to parasites grown in medium depleted of iron, which were readily killed by complement. The resistance to complement was dependent on iron concentration while divalent cations other than iron were ineffective, showing specific regulation of this property by iron. Lactoferrin, but not transferrin, rendered low-iron-parasites resistant to complement lysis, reinforcing the in vivo modulation by a known source of iron for this parasite. Pretreatment of high-iron, complement-resistant parasites with proteinase inhibitors resulted in lysis by complement, indicating that resistance was likely due to proteinase degradation of C3 on the trichomonal surface.

Involvement of dsRNA virus in the protein composition and growth kinetics of host Trichomonas vaginalis

Trichomonas vaginalis harbors a double-stranded (ds)-RNA virus, and the presence of virus is related to upregulated expression and phenotypic variation of a prominent immunogen (Khoshnan A, Alderete JF (1994) J Virol 68: 4035-4038). To further test the influence of virus on T. vaginalis, virus-infected (V+) isolates were compared to virus-free (V-), agar-cloned progeny trichomonads derived from the parental isolates for accumulation of total proteins and cysteine proteinases. Comparative high resolution two dimensional (2D)-SDS-PAGE was performed of trichomonads grown in a chemostat under identical conditions. At least 47 proteins were identified as specifically expressed by representative V+ isolate 347, and approximately 41 spots were specific to the corresponding V- progeny, showing an association between virus and the presence and absence of parasite proteins. Qualitatively and quantitatively dissimilar cysteine proteinase patterns were detected from numerous V+ isolates and the V- progeny. A 2D analysis for isolate 347 showed the appearance of unique proteinase activities for parental parasites and presence of at least one proteinase in the V- progeny. Finally, the V+ T. vaginalis isolate 347, but not the V- isolate 347 progeny nor other V+ isolates, underwent fluctuations in density during chemostat growth allowing for purification of virus particles from the V+ isolate 347 supernatants during decreased parasite density.

Clinical and economic strategies in outpatient medical care during the COVID-19 pandemic

The COVID-19 pandemic has resulted in significant clinical and economic consequences for medical practices of all specialties across the nation. Although the clinical implications are of the utmost importance, the economic consequences have also been serious and resulted in substantial damage to the US healthcare system, including pain practices. Outpatient pain practices have had to significantly change their clinical care pathways, including the incorporation of telemedicine. Elective medical and interventional care has been postponed. For the most part, ambulatory surgical centers have had to cease operations. As patient volumes have decreased for non-emergent elective care, the financial indicators have deteriorated. This review article will provide insight into solutions to mitigate the clinical and economic challenges induced by COVID-19. Undoubtedly, the COVID-19 pandemic will have short-term and long-term implications for all medical practices and facilities. In order to survive, medical practices will need dynamic, operational, and creative strategic plans to mitigate the disruption in medical care and pathways for successful reintegration of clinical and surgical practice.

Fatal gadolinium-induced encephalopathy following accidental intrathecal administration: a case report and a comprehensive evidence-based review

Gadolinium-based contrast agents (GBCAs) have been suggested as off-label alternatives to iodine-based contrast agents for fluoroscopic imaging during interventional pain procedures. We report a case of accidental intrathecal administration of a GBCA during a neuraxial interventional pain procedure leading to acute gadolinium neurotoxicity, which resulted in encephalopathy and ultimately death. To our knowledge, it is the first published case of fatal intrathecal gadolinium-induced encephalopathy and the first published case of intrathecal gadoteridol causing serious neurologic complications. In addition, the case presented here is placed in context with an associated comprehensive, evidence-based review of the use of gadolinium in interventional pain procedures, addressing gadolinium chemistry and pharmacologic properties, neurotoxicity and radiology. Physicians must be aware that gadolinium poses a significant risk of acute neurotoxicity even in small doses. Until further safety research is performed, GBCAs should not be considered a safe alternative for use in neuraxial interventional spine procedures when there is a risk of inadvertent intrathecal administration.

Low-profile versus conventional metacarpal plating systems: a comparison of construct stiffness and strength

Smaller, lower-profile plates for metacarpal fixation may have the potential to reduce extensor tendon irritation and adhesions, but their sufficiency for stabilizing metacarpal fractures has not been studied. We investigated the relative stiffness and strength of low-profile and conventional plating systems. For apex dorsal bending (bending closed), no plates broke or had notable plastic deformation. The conventional plates exhibited higher overall bending rigidity than all other plates, but had a lower maximum bending moment than the smaller plates. In apex volar bending (bending open) and torsion, the conventional plates were remarkably more rigid and developed remarkably higher torque. In vivo metacarpal loads are primarily apex dorsal bending, and all plates performed well in this mode. Thus, the smaller, low-profile plates may be sufficient for metacarpal fixation, although patient compliance and the use of supplemental stabilization with a cast or splint should be considered.

Evaluation of Primary Care Physician Chronic Pain Management Practice Patterns

Background: The management of chronic pain is complex and often involves the integration of multiple clinical, humanistic, and economic factors. Primary care physicians (PCPs) are often at the forefront of managing chronic pain and often initiate pharmacological pain management therapy. To date little is known surrounding the pain management practices of PCPs. Objective: The purpose of this study is to assess the knowledge and practice of PCPs in management of chronic pain. Study Design: A survey. Setting: Western region of Pennsylvania, US. Methods: A cross-sectional questionnaire survey evaluated PCPs pain management treatment practices including assessment of chronic pain, procedural activities surrounding therapy, decision-making input, and knowledge for therapeutic pain management including the 5 main classes of medications. The questionnaire was developed based on a review of the literature including published chronic pain guidelines. The questionnaire was mailed to a convenience sample of 300 PCPs practicing in Western Pennsylvania. The study was approved by the University Institutional Review Board. Results: The survey had a response rate of 16%. The respondents on average treated 30 chronic pain patients per month predominately in a community setting. The most common conditions treated included osteoarthritis, back and neuropathic pain. Although the major reported source of education was published literature, only 67% respondents referred to pain management guidelines. Multiple knowledge and practice gaps were identified surrounding pharmacological treatment, medication management including compliance practices, and pain assessment. Limitations: Although low, the response rate is comparable to response rates for other chronic pain management topics including anticoagulation and prescription patterns for chronic pain physicians. Also, greater than 50% of the respondents were from private practice, therefore, the results may not pertain to other practice settings including academic and hospital-based practices. Conclusions: The survey provided significant insight into PCP practices and highlights areas for future educational efforts. Further opioid prescribing education would be beneficial especially regarding the utilization of opioid risk assessment tools, the selection of opioids, and opioid end organ effects. Furthermore, patient education on the realities of chronic pain management and the importance of nonpharmacological treatment are needed in order to reduce the challenges faced by PCPs surrounding chronic pain management. Key words: Chronic pain, primary care physician, pain management, survey questionnaire

Unique double-stranded RNAs associated with the Trichomonas vaginalis virus are synthesized by viral RNA-dependent RNA polymerase

Most Trichomonas vaginalis isolates are carriers of the multisegmented double-stranded RNA (dsRNA) virus. In vitro polymerase assays were performed to demonstrate the RNA-dependent RNA polymerase (RDRP) activity of purified particles. Transcripts which comigrated with the dsRNAs of the virus were readily detected as synthesized products, indicating viral RDRP activity. In addition, smaller-sized dsRNA species, possibly two of approximately 700 bp (s1) and one of 500 bp (s2), were synthesized by purified virus particles of the CsCl gradient surrounding the virus peak. No cross-hybridization with either s1 or s2 and the dsRNA segments occurred, suggesting that s1 and s2 were synthesized from different templates. An RNase A protection assay revealed that the synthesized s1 and s2 polymerase products were double stranded. Furthermore, hybridization of products with strand-specific RNA of s1 generated from cDNA indicated that only one strand was synthesized in vitro. s1 and s2 were not visualized in ethidium bromide-stained agarose gels of dsRNA of infected trichomonads grown in batch cultures. However, dsRNA profiles of the same infected organisms cultivated under defined continuous-flow conditions contained readily detectable levels of s1 and s2, indicating that amplification of s1 and s2 occurred under specific environmental conditions. These newly discovered dsRNAs were not detected in all of the virus-carrying isolates. Finally, it is noteworthy that the s1 and s2 dsRNAs and the RDRP activity were not detected in trichomonal isolates without virus or in virus-negative progeny derived from virus-positive parental isolates. These data indicate the possibility of variations in the number of dsRNAs and/or of the presence of satellites in trichomonads infected with the multisegmented virus.

Composite measure to assess efficacy/gastrointestinal tolerability of tapentadol ER versus oxycodone CR for chronic pain: pooled analysis of randomized studies

OBJECTIVE

To evaluate a composite measure for chronic pain that balances pain relief with tolerability.

DESIGN

Post hoc meta-analysis of three randomized, multicenter, double-blind studies.

PARTICIPANTS

Subjects with moderate-to-severe chronic osteoarthritis knee pain or low back pain who had been randomized to receive active treatment with tapentadol extended release (ER; n = 978) or oxycodone controlled release (CR; n = 999). Twenty-two subjects were excluded, mainly because they did not receive treatment.

MAIN OUTCOME MEASURES

We defined the composite measure as ≥30 percent pain relief without nausea/vomiting/constipation and without discontinuations (≥30 percent PRT [pain relief/tolerability]). We also considered ≥50 percent PRT as well as ≥30 percent and ≥50 percent pain relief without any adverse events of any type. To further evaluate ≥30 percent PRT, we studied its relationship with four patient-reported outcomes: EQ-5D, Physical and Mental Component Summaries of SF-36, Patient Global Impression of Change, and Patient Assessment of Constipation Symptoms.

RESULTS

At week 12, tapentadol ER recipients were more likely to have ≥30 percent PRT than oxycodone CR recipients (OR, 3.15; 95% CI, 2.47, 4.00; p < 0.001). Significant differences were also observed with the other three composite measures (p < 0.001). At week 12, subjects with ≥30 percent PRT had more favorable changes in all patient-reported outcomes than those without and were more likely to have threshold changes in EQ-5D and SF-36 (all p < 0.001).

CONCLUSIONS

Tapentadol ER was associated with significantly better composite outcomes than oxycodone CR. Because both pain relief and gastrointestinal tolerability appeared to be related to outcomes, the composite measure may represent a useful tool for comparing opioids that merits further evaluation.

Spinal cord stimulator education during pain fellowship: unmet training needs and factors that impact future practice

Background and objectives

With a growing need for non-opioid chronic pain treatments, pain physicians should understand the proper utilization of neuromodulation therapies to provide the most comprehensive care. We aimed to identify the unmet training needs that deter physicians from using spinal cord stimulation (SCS) devices.

Methods

Internet-based surveys were fielded to fellows enrolled in pain fellowships during the 2016–2017 academic year accredited by the Accreditation Council for Graduate Medical Education and past pain fellows identified through pain medicine societies and SCS manufacturers.

Results

Current fellows were more likely to have received SCS training during fellowship compared with past fellows (100.0% vs 84.0%), yet there was variability in fellows’ SCS experiences with a wide range of trials and implants performed. Forty-six percent of current fellows felt there was an unmet training need regarding SCS. Deficiency in SCS case volume was the most common barrier that was noted (38.5%), followed by lack of SCS curriculum (30.8%) and lack of faculty with SCS expertise (23.1%). Lack of training was a predominant reason for past fellows choosing not to use SCS devices postfellowship. The majority of current and past fellows (79.5% and 55.4%, respectively) strongly supported direct training of fellows by SCS manufacturers.

Conclusions

While SCS training during pain fellowship has become more universal, the experiences that fellows receive are highly variable, and most rely on industry-sponsored programs to supplement training deficiencies. Standardization of SCS procedures may also enable less experienced providers to navigate the SCS treatment algorithm.

The vagina has reducing environment sufficient for activation of Trichomonas vaginalis cysteine proteinases

BACKGROUND

Trichomonas vaginalis, a worldwide distributed sexually transmitted protozoan, is remarkable for synthesis of numerous, distinct cysteine proteinases, the significance of which is evidenced by the presence in vivo of soluble proteinases in secretions and antiproteinase antibody in serum of patients with trichomonosis. These proteinases purportedly play a role in host parasitism and immune evasion.

OBJECTIVE

It is known that for cysteine proteinases to be functional, they must be activated by disulphide reducing reagents. Whether or not the host vaginal environment has the reducing environment essential for activation of the trichomonad cysteine proteinases is unknown. Our goal, therefore, was to determine whether or not vaginal secretions had sufficient reducing power to activate the trichomonad proteinases.

METHODS

48 vaginal washes (VWs) from patients were assayed for reducing equivalents and a score in dithiothreitol (DTT) reducing equivalents was assigned to each VW. Activation of trichomonad cysteine proteinases was then tested under the range of reducing equivalents detected from VWs. The possible protective effect of hydrogen peroxide, an oxidising agent produced by some Lactobacillus species, on proteinase activity was also determined.

RESULTS

Nine of 48 VWs (18.7%) possessed < or = 10 microM DTT reducing equivalents, four VWs (8.3%) had from 20 microM DTT to 40 microM DTT reducing equivalents, and most (50%) were between 10 microM to 15 microM. Overall, the range in VWs was from approximately 10 microM to 40 microM reducing equivalents. Importantly, data suggest differential proteinase activation over this in vivo range of reducing level. Only two T vaginalis cysteine proteinase activities were stimulated at 2.5 microM DTT in contrast with all proteinase activities present at 40 microM DTT, albeit quantitatively diminished compared with the activity at 1 mM DTT, the concentration routinely used in vitro. Finally, hydrogen peroxide reversibly neutralised all trichomonad proteinases.

CONCLUSIONS

These results show that the vagina of women has a reducing environment adequate for activation of trichomonad proteinases. The data underscore that the host environment plays a role in the host-parasite interrelation. Finally, hypotheses can now be formulated to help explain resistance and susceptibility to infection commonly reported among women and between men and women with trichomonosis.

Pulse Dosing of 10 kHz Paresthesia-Independent Spinal Cord Stimulation Provides Same Efficacy with Substantial Reduction of Device Recharge Time

Objective

This study was designed to assess whether using pulse dosing (PD) (regularly cycled intermittent stimulation) of high-frequency 10-kHz spinal cord stimulation (10-kHz SCS) can reduce device recharge time while maintaining efficacy in patients with chronic intractable back pain with or without leg pain.

Design

Prospective, multicenter, observational study.

Methods

Patients successfully using 10-kHz SCS at 100%ON (i.e., continuously with no PD) for >3 months were consecutively enrolled. After a 1-week baseline period of documenting their pain twice daily on a 0–10 numerical rating scale (NRS) using 100%ON of their “favorite” program, all subjects were reprogrammed to 14%PD for 10–14 days. If subjects preferred 14%PD to 100%ON, they were programmed to 3%PD; otherwise, they were programmed to 50%PD. Subjects used this next program for another 10–14 days. Subjects then entered a 3-month observational period during which they were requested to use but not limited to their most preferred %PD program. Toward the end of 3 months, subjects completed a 7-day NRS diary and indicated a final %PD program preference. Study endpoints included %PD preference, mean diary NRS by %PD, and daily minutes and patterns of charging.

Results

Of 31 subjects completing the study, 81% preferred less than 100%ON. Among the subjects, 39% preferred 3%PD, 32% preferred 14%PD, 10% preferred 50%PD, and 19% preferred 100%ON. Average daily charge durations were 8.3 ± 3.1 minutes for 3%PD, 13.9 ± 4.9 minutes for 14%PD, 26.2 ± 7.4 minutes for 50%PD, and 43.8 ± 10.9 minutes for 100%ON. Regression modeling suggested that pain relief was weighted as more than twice as influential as charging in preference for reduced %PD.

Conclusions

This prospective study suggests that 10-kHz SCS therapy with PD may be successfully used in a large majority of 10-kHz SCS responders, maintaining efficacy while reducing device charging time by nearly two thirds.