Informed Consent for Spine Procedures: Best Practice Guideline from the American Society of Pain and Neuroscience (ASPN)

Introduction

The evolution of treatment options for painful spinal disorders in diverse settings has produced a variety of approaches to patient care among clinicians from multiple professional backgrounds. The American Society of Pain and Neuroscience (ASPN) Best Practice group identified a need for a multidisciplinary guideline regarding appropriate and effective informed consent processes for spine procedures.

Objective

The ASPN Informed Consent Guideline was developed to provide clinicians with a comprehensive evaluation of patient consent practices during the treatment of spine pathology.

Methods

After a needs assessment, ASPN determined that best practice regarding proper informed consent for spinal procedures was needed and a process of selecting faculty was developed based on expertise, diversity, and knowledge of the subject matter. A comprehensive literature search was conducted and when appropriate, evidence grading was performed. Recommendations were based on evidence when available, and when limited, based on consensus opinion.

Results

Following a comprehensive review and analysis of the available evidence, the ASPN Informed Consent Guideline group rated the literature to assist with specification of best practice regarding patient consent during the management of spine disorders.

Conclusion

Careful attention to informed consent is critical in achieving an optimal outcome and properly educating patients. This process involves a discussion of risks, advantages, and alternatives to treatment. As the field of interventional pain and spine continues to grow, it is imperative that clinicians effectively educate patients and obtain comprehensive informed consent for invasive procedures. This consent should be tailored to the patient's specific needs to ensure an essential recognition of patient autonomy and reasonable expectations of treatment.

Vertebral Augmentation: Is It Time to Get Past the Pain? A Consensus Statement from the Sardinia Spine and Stroke Congress

Vertebral augmentation has been used to treat painful vertebral compression fractures and metastatic lesions in millions of patients around the world. An international group of subject matter experts have considered the evidence, including but not limited to mortality. These considerations led them to ask whether it is appropriate to allow the subjective measure of pain to so dominate the clinical decision of whether to proceed with augmentation. The discussions that ensued are related below.

Consensus Guidelines on Interventional Therapies for Knee Pain (STEP Guidelines) from the American Society of Pain and Neuroscience

Knee pain is second only to the back as the most commonly reported area of pain in the human body. With an overall prevalence of 46.2%, its impact on disability, lost productivity, and cost on healthcare cannot be overlooked. Due to the pervasiveness of knee pain in the general population, there are no shortages of treatment options available for addressing the symptoms. Ranging from physical therapy and pharmacologic agents to interventional pain procedures to surgical options, practitioners have a wide array of options to choose from – unfortunately, there is no consensus on which treatments are “better” and when they should be offered in comparison to others. While it is generally accepted that less invasive treatments should be offered before more invasive ones, there is a lack of agreement on the order in which the less invasive are to be presented. In an effort to standardize the treatment of this extremely prevalent pathology, the authors present an all-encompassing set of guidelines on the treatment of knee pain based on an extensive literature search and data grading for each of the available alternative that will allow practitioners the ability to compare and contrast each option.

Cooled radiofrequency ablation of genicular nerves provides 24-Month durability in the management of osteoarthritic knee pain: Outcomes from a prospective, multicenter, randomized trial

Objective

To assess long‐term outcomes of cooled radiofrequency ablation (CRFA) of genicular nerves for chronic knee pain due to osteoarthritis (OA).

Methods

A prospective, observational extension of a randomized, controlled trial was conducted on adults randomized to CRFA. Subjects were part of a 12‐month clinical trial comparing CRFA of genicular nerves to a single hyaluronic injection for treatment of chronic OA knee pain, who then agreed to visits at 18‐ and 24‐months post CRFA and had not undergone another knee procedure since. The subjects were evaluated for pain using the Numeric Rating Scale (NRS) function using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), subjective benefit using the Global Perceived Effect (GPE) scale, quality of life using the EuroQol‐5‐Dimensions‐5 Level (EQ‐5D‐5L) questionnaire, and safety.

Results

Of 57 subjects eligible, 36 enrolled; 32 completed the 18‐month visit with a mean NRS score of 2.4 and 22 (69%) reporting ≥50% reduction in pain from baseline (primary endpoint); 27 completed the 24‐month visit, with a mean NRS of 3.4 and 17 (63%) reporting ≥50% pain relief. Functional and quality of life improvements persisted similarly, with mean changes from baseline of 53.5% and 34.9% in WOMAC total scores, and 24.8% and 10.7% in EQ‐5D‐5L Index scores, at 18‐ and 24‐months, respectively. There were no identified safety concerns in this patient cohort.

Conclusion

In this subset of subjects, CRFA of genicular nerves provided durable pain relief, improved function, and improved quality of life extending to 24 months post procedure, with no significant safety concerns.

Cooled Radiofrequency Ablation Compared with a Single Injection of Hyaluronic Acid for Chronic Knee Pain: A Multicenter, Randomized Clinical Trial Demonstrating Greater Efficacy and Equivalent Safety for Cooled Radiofrequency Ablation

BACKGROUND

Knee osteoarthritis is a painful and sometimes debilitating disease that often affects patients for years. Current treatments include short-lasting and often repetitive nonsurgical options, followed by surgical intervention for appropriate candidates. Cooled radiofrequency ablation (CRFA) is a minimally invasive procedure for the treatment of pain related to knee osteoarthritis. This trial compared the efficacy and safety of CRFA with those of a single hyaluronic acid (HA) injection.

METHODS

Two hundred and sixty subjects with knee osteoarthritis pain that was inadequately responsive to prior nonoperative modalities were screened for enrollment in this multicenter, randomized trial. One hundred and eighty-two subjects who met the inclusion criteria underwent diagnostic block injections and those with a minimum of 50% pain relief were randomized to receive either CRFA on 4 genicular nerves or a single HA injection. One hundred and seventy-five subjects were treated (88 with CRFA and 87 with HA). Evaluations for pain (Numeric Rating Scale [NRS]), function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), quality of life (Global Perceived Effect [GPE] score and EuroQol-5 Dimensions-5 Level [EQ-5D-5L] questionnaire), and safety were performed at 1, 3, and 6 months after treatment.

RESULTS

Demographic characteristics did not differ significantly between the 2 study groups. A total of 158 subjects (76 in the CRFA group and 82 in the HA group) completed the 6-month post-treatment follow-up. In the CRFA group, 71% of the subjects had ≥50% reduction in the NRS pain score (primary end point) compared with 38% in the HA group (p < 0.0001). At 6 months, the mean NRS score reduction was 4.1 ± 2.2 for the CRFA group compared with 2.5 ± 2.5 for the HA group (p < 0.0001). The mean WOMAC score improvement at 6 months from baseline was 48.2% in the CRFA group and 22.6% in the HA group (p < 0.0001). At 6 months, 72% of the subjects in the CRFA group reported improvement in the GPE score compared with 40% in the HA group (p < 0.0001).

CONCLUSIONS

CRFA-treated subjects demonstrated a significant improvement in pain relief and overall function compared with subjects treated with a single injection of HA. No serious adverse events related to either procedure were noted, and the overall adverse-event profiles were similar.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Cooled radiofrequency ablation provides extended clinical utility in the management of knee osteoarthritis: 12-month results from a prospective, multi-center, randomized, cross-over trial comparing cooled radiofrequency ablation to a single hyaluronic acid injection

BACKGROUND

Safe and effective non-surgical treatments are an important part of the knee osteoarthritis (OA) treatment algorithm. Cooled radiofrequency ablation (CRFA) and hyaluronic acid (HA) injections are two commonly used modalities to manage symptoms associated with knee OA.

METHODS

A prospective 1:1 randomized study was conducted in 177 patients comparing CRFA to HA injection with follow-ups at 1, 3, 6 and 12 months. HA subjects with unsatisfactory outcomes at 6-months were allowed to crossover and receive CRFA. Knee pain (numeric rating scale = NRS), WOMAC Index (pain, stiffness and physical function), overall quality of life (global perceived effect = GPE, EQ-5D-5 L), and adverse events were measured.

RESULTS

At 12-months, 65.2% of subjects in the CRFA cohort reported ≥50% pain relief from baseline. Mean NRS pain score was 2.8 ± 2.4 at 12 months (baseline 6.9 ± 0.8). Subjects in the CRFA cohort saw a 46.2% improvement in total WOMAC score at the 12-month timepoint. 64.5% of subjects in the crossover cohort reported ≥50% pain relief from baseline, with a mean NRS pain score of 3.0 ± 2.4 at 12 months (baseline 7.0 ± 1.0). After receiving CRFA, subjects in the crossover cohort had a 27.5% improvement in total WOMAC score. All subjects receiving CRFA reported significant improvement in quality of life. There were no serious adverse events related to either procedure and overall adverse event profiles were similar.

CONCLUSION

A majority of subjects treated with CRFA demonstrated sustained knee pain relief for at least 12-months. Additionally, CRFA provided significant pain relief for HA subjects who crossed over 6 months after treatment.

TRIAL REGISTRATION

This trial was registered on ClinicalTrials.gov, NCT03381248. Registered 27 December 2017.

Comprehensive Evidence-Based Guidelines for Facet Joint Interventions in the Management of Chronic Spinal Pain: American Society of Interventional Pain Physicians (ASIPP) Guidelines Facet Joint Interventions 2020 Guidelines

BACKGROUND

Chronic axial spinal pain is one of the major causes of significant disability and health care costs, with facet joints as one of the proven causes of pain.

OBJECTIVE

To provide evidence-based guidance in performing diagnostic and therapeutic facet joint interventions.

METHODS

The methodology utilized included the development of objectives and key questions with utilization of trustworthy standards. The literature pertaining to all aspects of facet joint interventions, was reviewed, with a best evidence synthesis of available literature and utilizing grading for recommendations.Summary of Evidence and Recommendations:Non-interventional diagnosis: • The level of evidence is II in selecting patients for facet joint nerve blocks at least 3 months after onset and failure of conservative management, with strong strength of recommendation for physical examination and clinical assessment. • The level of evidence is IV for accurate diagnosis of facet joint pain with physical examination based on symptoms and signs, with weak strength of recommendation. Imaging: • The level of evidence is I with strong strength of recommendation, for mandatory fluoroscopic or computed tomography (CT) guidance for all facet joint interventions. • The level of evidence is III with weak strength of recommendation for single photon emission computed tomography (SPECT) . • The level of evidence is V with weak strength of recommendation for scintography, magnetic resonance imaging (MRI), and computed tomography (CT) .Interventional Diagnosis:Lumbar Spine: • The level of evidence is I to II with moderate to strong strength of recommendation for lumbar diagnostic facet joint nerve blocks. • Ten relevant diagnostic accuracy studies with 4 of 10 studies utilizing controlled comparative local anesthetics with concordant pain relief criterion standard of ≥80% were included. • The prevalence rates ranged from 27% to 40% with false-positive rates of 27% to 47%, with ≥80% pain relief.Cervical Spine: • The level of evidence is II with moderate strength of recommendation. • Ten relevant diagnostic accuracy studies, 9 of the 10 studies with either controlled comparative local anesthetic blocks or placebo controls with concordant pain relief with a criterion standard of ≥80% were included. • The prevalence and false-positive rates ranged from 29% to 60% and of 27% to 63%, with high variability. Thoracic Spine: • The level of evidence is II with moderate strength of recommendation. • Three relevant diagnostic accuracy studies, with controlled comparative local anesthetic blocks, with concordant pain relief, with a criterion standard of ≥80% were included. • The prevalence varied from 34% to 48%, whereas false-positive rates varied from 42% to 58%.Therapeutic Facet Joint Interventions: Lumbar Spine: • The level of evidence is II with moderate strength of recommendation for lumbar radiofrequency ablation with inclusion of 11 relevant randomized controlled trials (RCTs) with 2 negative studies and 4 studies with long-term improvement. • The level of evidence is II with moderate strength of recommendation for therapeutic lumbar facet joint nerve blocks with inclusion of 3 relevant randomized controlled trials, with long-term improvement. • The level of evidence is IV with weak strength of recommendation for lumbar facet joint intraarticular injections with inclusion of 9 relevant randomized controlled trials, with majority of them showing lack of effectiveness without the use of local anesthetic. Cervical Spine: • The level of evidence is II with moderate strength of recommendation for cervical radiofrequency ablation with inclusion of one randomized controlled trial with positive results and 2 observational studies with long-term improvement. • The level of evidence is II with moderate strength of recommendation for therapeutic cervical facet joint nerve blocks with inclusion of one relevant randomized controlled trial and 3 observational studies, with long-term improvement. • The level of evidence is V with weak strength of recommendation for cervical intraarticular facet joint injections with inclusion of 3 relevant randomized controlled trials, with 2 observational studies, the majority showing lack of effectiveness, whereas one study with 6-month follow-up, showed lack of long-term improvement. Thoracic Spine: • The level of evidence is III with weak to moderate strength of recommendation with emerging evidence for thoracic radiofrequency ablation with inclusion of one relevant randomized controlled trial and 3 observational studies. • The level of evidence is II with moderate strength of recommendation for thoracic therapeutic facet joint nerve blocks with inclusion of 2 randomized controlled trials and one observational study with long-term improvement. • The level of evidence is III with weak to moderate strength of recommendation for thoracic intraarticular facet joint injections with inclusion of one randomized controlled trial with 6 month follow-up, with emerging evidence. Antithrombotic Therapy: • Facet joint interventions are considered as moderate to low risk procedures; consequently, antithrombotic therapy may be continued based on overall general status. Sedation: • The level of evidence is II with moderate strength of recommendation to avoid opioid analgesics during the diagnosis with interventional techniques. • The level of evidence is II with moderate strength of recommendation that moderate sedation may be utilized for patient comfort and to control anxiety for therapeutic facet joint interventions.

LIMITATIONS

The limitations of these guidelines include a paucity of high-quality studies in the majority of aspects of diagnosis and therapy.

CONCLUSIONS

These facet joint intervention guidelines were prepared with a comprehensive review of the literature with methodologic quality assessment with determination of level of evidence and strength of recommendations.

KEY WORDS

Chronic spinal pain, interventional techniques, diagnostic blocks, therapeutic interventions, facet joint nerve blocks, intraarticular injections, radiofrequency neurolysis.

Bone Marrow Concentrate (BMC) Therapy in Musculoskeletal Disorders: Evidence-Based Policy Position Statement of American Society of Interventional Pain Physicians (ASIPP)

BACKGROUND

The use of bone marrow concentrate (BMC) for treatment of musculoskeletal disorders has become increasingly popular over the last several years, as technology has improved along with the need for better solutions for these pathologies. The use of cellular tissue raises a number of issues regarding the US Food and Drug Administration's (FDA) regulation in classifying these treatments as a drug versus just autologous tissue transplantation. In the case of BMC in musculoskeletal and spine care, this determination will likely hinge on whether BMC is homologous to the musculoskeletal system and spine.

OBJECTIVES

The aim of this review is to describe the current regulatory guidelines set in place by the FDA, specifically the terminology around "minimal manipulation" and "homologous use" within Regulation 21 CFR Part 1271, and specifically how this applies to the use of BMC in interventional musculoskeletal medicine.

METHODS

The methodology utilized here is similar to the methodology utilized in preparation of multiple guidelines employing the experience of a panel of experts from various medical specialties and subspecialties from differing regions of the world. The collaborators who developed these position statements have submitted their appropriate disclosures of conflicts of interest. Trustworthy standards were employed in the creation of these position statements. The literature pertaining to BMC, its effectiveness, adverse consequences, FDA regulations, criteria for meeting the standards of minimal manipulation, and homologous use were comprehensively reviewed using a best evidence synthesis of the available and relevant literature. RESULTS/Summary of Evidence: In conjunction with evidence-based medicine principles, the following position statements were developed: Statement 1: Based on a review of the literature in discussing the preparation of BMC using accepted methodologies, there is strong evidence of minimal manipulation in its preparation, and moderate evidence for homologous utility for various musculoskeletal and spinal conditions qualifies for the same surgical exemption. Statement 2: Assessment of clinical effectiveness based on extensive literature shows emerging evidence for multiple musculoskeletal and spinal conditions. • The evidence is highest for knee osteoarthritis with level II evidence based on relevant systematic reviews, randomized controlled trials and nonrandomized studies. There is level III evidence for knee cartilage conditions. • Based on the relevant systematic reviews, randomized trials, and nonrandomized studies, the evidence for disc injections is level III. • Based on the available literature without appropriate systematic reviews or randomized controlled trials, the evidence for all other conditions is level IV or limited for BMC injections. Statement 3: Based on an extensive review of the literature, there is strong evidence for the safety of BMC when performed by trained physicians with the appropriate precautions under image guidance utilizing a sterile technique. Statement 4: Musculoskeletal disorders and spinal disorders with related disability for economic and human toll, despite advancements with a wide array of treatment modalities. Statement 5: The 21st Century Cures Act was enacted in December 2016 with provisions to accelerate the development and translation of promising new therapies into clinical evaluation and use. Statement 6: Development of cell-based therapies is rapidly proliferating in a number of disease areas, including musculoskeletal disorders and spine. With mixed results, these therapies are greatly outpacing the evidence. The reckless publicity with unsubstantiated claims of beneficial outcomes having putative potential, and has led the FDA Federal Trade Commission (FTC) to issue multiple warnings. Thus the US FDA is considering the appropriateness of using various therapies, including BMC, for homologous use. Statement 7: Since the 1980's and the description of mesenchymal stem cells by Caplan et al, (now called medicinal signaling cells), the use of BMC in musculoskeletal and spinal disorders has been increasing in the management of pain and promoting tissue healing. Statement 8: The Public Health Service Act (PHSA) of the FDA requires minimal manipulation under same surgical procedure exemption. Homologous use of BMC in musculoskeletal and spinal disorders is provided by preclinical and clinical evidence. Statement 9: If the FDA does not accept BMC as homologous, then it will require an Investigational New Drug (IND) classification with FDA (351) cellular drug approval for use. Statement 10: This literature review and these position statements establish compliance with the FDA's intent and corroborates its present description of BMC as homologous with same surgical exemption, and exempt from IND, for use of BMC for treatment of musculoskeletal tissues, such as cartilage, bones, ligaments, muscles, tendons, and spinal discs.

CONCLUSIONS

Based on the review of all available and pertinent literature, multiple position statements have been developed showing that BMC in musculoskeletal disorders meets the criteria of minimal manipulation and homologous use.

KEY WORDS

Cell-based therapies, bone marrow concentrate, mesenchymal stem cells, medicinal signaling cells, Food and Drug Administration, human cells, tissues, and cellular tissue-based products, Public Health Service Act (PHSA), minimal manipulation, homologous use, same surgical procedure exemption.

Number Needed to Treat with Vertebral Augmentation to Save a Life

BACKGROUND AND PURPOSE

Evidence from randomized controlled trials for the efficacy of vertebral augmentation in vertebral compression fractures has been mixed. However, claims-based analyses from national registries or insurance datasets have demonstrated a significant mortality benefit for patients with vertebral compression fractures who receive vertebral augmentation. The purpose of this study was to calculate the number needed to treat to save 1 life at 1 year and up to 5 years after vertebral augmentation.

MATERIALS AND METHODS

A 10-year sample of the 100% US Medicare data base was used to identify patients with vertebral compression fractures treated with nonsurgical management, balloon kyphoplasty, and vertebroplasty. The number needed to treat was calculated between augmentation and nonsurgical management groups from years 1-5 following a vertebral compression fracture diagnosis, using survival probabilities for each management approach.

RESULTS

The adjusted number needed to treat to save 1 life for nonsurgical management versus kyphoplasty ranged from 14.8 at year 1 to 11.9 at year 5. The adjusted number needed to treat for nonsurgical management versus vertebroplasty ranged from 22.8 at year 1 to 23.8 at year 5.

CONCLUSIONS

Both augmentation modalities conferred a prominent mortality benefit over nonsurgical management in this analysis of the US Medicare registry, with a low number needed to treat. The calculations based on this data base resulted in a low number needed to treat to save 1 life at 1 year and at 5 years.

A prospective, randomized, multicenter study of intraosseous basivertebral nerve ablation for the treatment of chronic low back pain

BACKGROUND CONTEXT

Current literature suggests that degenerated or damaged vertebral endplates are a significant cause of chronic low back pain (LBP) that is not adequately addressed by standard care. Prior 2-year data from the treatment arm of a sham-controlled randomized controlled trial (RCT) showed maintenance of clinical improvements at 2 years following radiofrequency (RF) ablation of the basivertebral nerve (BVN).

PURPOSE

The purpose of this RCT was to compare the effectiveness of intraosseous RF ablation of the BVN to standard care for the treatment of chronic LBP in a specific subgroup of patients suspected to have vertebrogenic related symptomatology.

STUDY DESIGN/SETTING

A prospective, parallel, open label RCT was conducted at 20 U.S. sites.

PATIENT SAMPLE

A total of 140 patients with chronic LBP of at least 6 months duration, with Modic Type 1 or 2 vertebral endplate changes between L3 and S1, were randomized 1:1 to undergo either RF ablation of the BVN or continue standard care.

OUTCOME MEASURES

Oswestry Disability Index (ODI) was collected at baseline, 3, 6, 9, and 12-months postprocedure. Secondary outcome measures included a 10-point Visual Analog Scale (VAS) for LBP, ODI and VAS responder rates, SF-36, and EQ-5D-5L. The primary endpoint was a between-arm comparison of the mean change in ODI from baseline to 3 months post-treatment.

METHODS

Patients were randomized 1:1 to receive RF ablation or to continue standard care. Self-reported patient outcomes were collected using validated questionnaires at each study visit. An interim analysis to assess for superiority was prespecified and overseen by an independent data management committee when a minimum of 60% of patients had completed their 3-month primary endpoint visit.

RESULTS

The interim analysis showed clear statistical superiority (p<.001) for all primary and secondary patient-reported outcome measures in the RF ablation arm compared with the standard care arm. This resulted in a data management committee recommendation to halt enrollment in the study and offer early cross-over to the control arm. These results are comprised of the outcomes of the 104 patients included in the intent-to-treat analysis of the 3-month primary endpoint, which included 51 patients in the RF ablation arm and 53 patients in the standard care arm. Baseline ODI was 46.1, VAS was 6.67, and mean age was 50 years. The percentage of patients with LBP symptoms ≥5 years was 67.3%. Comparing the RF ablation arm to the standard care arm, the mean changes in ODI at 3 months were -25.3 points versus -4.4 points, respectively, resulting in an adjusted difference of 20.9 points (p<.001). Mean changes in VAS were -3.46 versus -1.02, respectively, an adjusted difference of 2.44 cm (p<.001). In the RF ablation arm, 74.5% of patients achieved a ≥10-point improvement in ODI, compared with 32.7% in the standard care arm (p<0.001).

CONCLUSIONS

Minimally invasive RF ablation of the BVN led to significant improvement of pain and function at 3-months in patients with chronic vertebrogenic related LBP.

Responsible, Safe, and Effective Use of Biologics in the Management of Low Back Pain: American Society of Interventional Pain Physicians (ASIPP) Guidelines

BACKGROUND

Regenerative medicine is a medical subspecialty that seeks to recruit and enhance the body's own inherent healing armamentarium in the treatment of patient pathology. This therapy's intention is to assist in the repair, and to potentially replace or restore damaged tissue through the use of autologous or allogenic biologics. This field is rising like a Phoenix from the ashes of underperforming conventional therapy midst the hopes and high expectations of patients and medical personnel alike. But, because this is a relatively new area of medicine that has yet to substantiate its outcomes, care must be taken in its public presentation and promises as well as in its use.

OBJECTIVE

To provide guidance for the responsible, safe, and effective use of biologic therapy in the lumbar spine. To present a template on which to build standardized therapies using biologics. To ground potential administrators of biologics in the knowledge of the current outcome statistics and to stimulate those interested in providing biologic therapy to participate in high quality research that will ultimately promote and further advance this area of medicine.

METHODS

The methodology used has included the development of objectives and key questions. A panel of experts from various medical specialties and subspecialties as well as differing regions collaborated in the formation of these guidelines and submitted (if any) their appropriate disclosures of conflicts of interest. Trustworthy standards were employed in the creation of these guidelines. The literature pertaining to regenerative medicine, its effectiveness, and adverse consequences was thoroughly reviewed using a best evidence synthesis of the available literature. The grading for recommendation was provided as described by the Agency for Healthcare Research and Quality (AHRQ).

SUMMARY OF EVIDENCE

Lumbar Disc Injections: Based on the available evidence regarding the use of platelet-rich plasma (PRP), including one high-quality randomized controlled trial (RCT), multiple moderate-quality observational studies, a single-arm meta-analysis and evidence from a systematic review, the qualitative evidence has been assessed as Level III (on a scale of Level I through V) using a qualitative modified approach to the grading of evidence based on best-evidence synthesis. Based on the available evidence regarding the use of medicinal signaling/ mesenchymal stem cell (MSCs) with a high-quality RCT, multiple moderate-quality observational studies, a single-arm meta-analysis, and 2 systematic reviews, the qualitative evidence has been assessed as Level III (on a scale of Level I through V) using a qualitative modified approach to the grading of evidence based on best evidence synthesis. Lumbar Epidural Injections Based on one high-quality RCT, multiple relevant moderate-quality observational studies and a single-arm meta-analysis, the qualitative evidence has been assessed as Level IV (on a scale of Level I through V) using a qualitative modified approach to the grading of evidence based on best evidence synthesis. Lumbar Facet Joint Injections Based on one high-quality RCT and 2 moderate-quality observational studies, the qualitative evidence for facet joint injections with PRP has been assessed as Level IV (on a scale of Level I through V) using a qualitative modified approach to the grading of evidence based on best evidence synthesis. Sacroiliac Joint Injection Based on one high-quality RCT, one moderate-quality observational study, and one low-quality case report, the qualitative evidence has been assessed as Level IV (on a scale of Level I through V) using a qualitative modified approach to the grading of evidence based on best evidence synthesis.

CONCLUSION

Based on the evidence synthesis summarized above, there is Level III evidence for intradiscal injections of PRP and MSCs, whereas the evidence is considered Level IV for lumbar facet joint, lumbar epidural, and sacroiliac joint injections of PRP, (on a scale of Level I through V) using a qualitative modified approach to the grading of evidence based on best evidence synthesis.Regenerative therapy should be provided to patients following diagnostic evidence of a need for biologic therapy, following a thorough discussion of the patient's needs and expectations, after properly educating the patient on the use and administration of biologics and in full light of the patient's medical history. Regenerative therapy may be provided independently or in conjunction with other modalities of treatment including a structured exercise program, physical therapy, behavioral therapy, and along with the appropriate conventional medical therapy as necessary. Appropriate precautions should be taken into consideration and followed prior to performing biologic therapy. Multiple guidelines from the Food and Drug Administration (FDA), potential limitations in the use of biologic therapy and the appropriate requirements for compliance with the FDA have been detailed in these guidelines.

KEY WORDS

Regenerative medicine, platelet-rich plasma, medicinal signaling cells, mesenchymal stem cells, stromal vascular fraction, bone marrow concentrate, chronic low back pain, discogenic pain, facet joint pain, Food and Drug Administration, minimal manipulation, evidence synthesis.

Responsible, Safe, and Effective Use of Antithrombotics and Anticoagulants in Patients Undergoing Interventional Techniques: American Society of Interventional Pain Physicians (ASIPP) Guidelines

BACKGROUND

Interventional pain management involves diagnosis and treatment of chronic pain. This specialty utilizes minimally invasive procedures to target therapeutics to the central nervous system and the spinal column. A subset of patients encountered in interventional pain are medicated using anticoagulant or antithrombotic drugs to mitigate thrombosis risk. Since these drugs target the clotting system, bleeding risk is a consideration accompanying interventional procedures. Importantly, discontinuation of anticoagulant or antithrombotic drugs exposes underlying thrombosis risk, which can lead to significant morbidity and mortality especially in those with coronary artery or cerebrovascular disease. This review summarizes the literature and provides guidelines based on best evidence for patients receiving anti-clotting therapy during interventional pain procedures.

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To provide a current and concise appraisal of the literature regarding an assessment of the bleeding risk during interventional techniques for patients taking anticoagulant and/or antithrombotic medications.

METHODS

A review of the available literature published on bleeding risk during interventional pain procedures, practice patterns and perioperative management of anticoagulant and antithrombotic therapy was conducted. Data sources included relevant literature identified through searches of EMBASE and PubMed from 1966 through August 2018 and manual searches of the bibliographies of known primary and review articles.

RESULTS

1. There is good evidence for risk stratification by categorizing multiple interventional techniques into low-risk, moderate-risk, and high-risk. Also, their risk should be upgraded based on other risk factors.2. There is good evidence for the risk of thromboembolic events in patients who interrupt antithrombotic therapy. 3. There is good evidence supporting discontinuation of low dose aspirin for high risk and moderate risk procedures for at least 3 days, and there is moderate evidence that these may be continued for low risk or some intermediate risk procedures.4. There is good evidence that discontinuation of anticoagulant therapy with warfarin, heparin, dabigatran (Pradaxa®), argatroban (Acova®), bivalirudin (Angiomax®), lepirudin (Refludan®), desirudin (Iprivask®), hirudin, apixaban (Eliquis®), rivaroxaban (Xarelto®), edoxaban (Savaysa®, Lixiana®), Betrixaban(Bevyxxa®), fondaparinux (Arixtra®) prior to interventional techniques with individual consideration of pharmacokinetics and pharmacodynamics of the drugs and individual risk factors increases safety.5. There is good evidence that diagnosis of epidural hematoma is based on severe pain at the site of the injection, rapid neurological deterioration, and MRI with surgical decompression with progressive neurological dysfunction to avoid neurological sequelae.6. There is good evidence that if thromboembolic risk is high, low molecular weight heparin bridge therapy can be instituted during cessation of the anticoagulant, and the low molecular weight heparin can be discontinued 24 hours before the pain procedure.7. There is fair evidence that the risk of thromboembolic events is higher than that of epidural hematoma formation with the interruption of antiplatelet therapy preceding interventional techniques, though both risks are significant.8. There is fair evidence that multiple variables including anatomic pathology with spinal stenosis and ankylosing spondylitis; high risk procedures and moderate risk procedures combined with anatomic risk factors; bleeding observed during the procedure, and multiple attempts during the procedures increase the risk for bleeding complications and epidural hematoma.9. There is fair evidence that discontinuation of phosphodiesterase inhibitors is optional (dipyridamole [Persantine], cilostazol [Pletal]. However, there is also fair evidence to discontinue Aggrenox [dipyridamole plus aspirin]) 3 days prior to undergoing interventional techniques of moderate and high risk. 10. There is fair evidence to make shared decision making between the patient and the treating physicians with the treating physician and to consider all the appropriate risks associated with continuation or discontinuation of antithrombotic or anticoagulant therapy.11. There is fair evidence that if thromboembolic risk is high antithrombotic therapy may be resumed 12 hours after the interventional procedure is performed.12. There is limited evidence that discontinuation of antiplatelet therapy (clopidogrel [Plavix®], ticlopidine [Ticlid®], Ticagrelor [Brilinta®] and prasugrel [Effient®]) avoids complications of significant bleeding and epidural hematomas.13. There is very limited evidence supporting the continuation or discontinuation of most NSAIDs, excluding aspirin, for 1 to 2 days and some 4 to 10 days, since these are utilized for pain management without cardiac or cerebral protective effect.

LIMITATIONS

The continued paucity of the literature with discordant recommendations.

CONCLUSION

Based on the survey of current literature, and published clinical guidelines, recommendations for patients presenting with ongoing antithrombotic therapy prior to interventional techniques are variable, and are based on comprehensive analysis of each patient and the risk-benefit analysis of intervention.

KEY WORDS

Perioperative bleeding, bleeding risk, practice patterns, anticoagulant therapy, antithrombotic therapy, interventional techniques, safety precautions, pain.

Review of Vertebral Augmentation: An Updated Meta-analysis of the Effectiveness

Background

To update vertebral augmentation literature by comparing outcomes between vertebroplasty (VP), balloon kyphoplasty (BKP), vertebral augmentation with implant (VAI), and nonsurgical management (NSM) for treating vertebral compression fractures (VCFs).

Methods

A PubMed literature search was conducted with keywords kyphoplasty, vertebroplasty, vertebral body stent, and vertebral augmentation AND implant for English-language articles from February 1, 2011, to November 22, 2016. Among the results, 25 met the inclusion criteria for the meta-analysis. Inclusion criteria were prospective comparative studies for mid-/lower-thoracic and lumbar VCFs enrolling at least 20 patients. Exclusion criteria included studies that were single arm, systematic reviews and meta-analyses, traumatic nonosteoporotic or cancer-related fractures, lack of clinical outcomes, or non-Level I and non-Level II studies. Standardized mean difference between baseline and end point for each outcome was calculated, and treatment groups were pooled using random effects meta-analysis.

Results

Visual analog scale pain reduction for BKP and VP was -4.05 and -3.88, respectively. VP was better than but not significantly different from NSM (-2.66), yet BKP showed significant improvement from both NSM and VAI (-2.77). The Oswestry Disability Index reduction for BKP showed a significant improvement over VAI (P < .001). There was no significant difference in changes between BKP and VP for anterior (P = .226) and posterior (P = .293) vertebral height restoration. There was no significant difference in subsequent fractures following BKP (32.7%; 95% confidence interval [CI]: 8.8%-56.6%) or VP (28.3%; 95% CI: 7.0%-49.7%) compared with NSM (15.9%; 95% CI: 5.2%-26.6%).

Conclusions/Level of Evidence

Based on Level I and II studies, BKP had significantly better and VP tended to have better pain reduction compared with NSM. BKP tended to have better height restoration than VP. Additionally, BKP had significant improvements in pain reduction and disability score as compared with VAI.

Clinical Relevance

This meta-analysis serves to further define and support the safety and efficacy of vertebral augmentation.

Pseudo-outbreak ofMycobacterium abscessusInfection Caused by Laboratory Contamination

Objective.

To investigate the cause(s) of an increased incidence of clinical cultures growingMycobacterium abscessusat a hospital in Florida.

Design.

Outbreak investigation.

Setting.

University-affiliated, tertiary-care hospital.

Methods.

A site visit was done during the first week of September 2006. We reviewed the medical records of patients from whomM. abscessuswas recovered during the period from January 1, 2003, through June 30, 2006. We collected environmental samples from various sites and evaluated specimen processing procedures in the microbiology laboratory. Isolates ofM. abscessusrecovered from the environment and from 12 randomly selected patients who sought medical care in 2006 were compared by pulsed-field gel electrophoresis (PFGE). Follow-up case surveillance was continued through March 31, 2007.

Results.

Specimens from 143 patients obtained from various anatomical sites grewM. abscessuson culture in 2005-2006, compared with specimens from 21 patients in 2003-2004. The 12 isolates from patients that were selected for molecular typing had indistinguishable PFGE patterns. Observations revealed no major breaches in the processing of mycobacterial specimens in the laboratory. Isolates grew only after prolonged incubation (mean ± SD, 45 ± 15 days) in test tubes containing diagonally oriented Middlebrook and Cohn 7H10 agar or Lowenstein-Jensen medium. Environmental samples obtained from the inside of the specimen incubator grewM. abscessuson culture. A test tube containing diagonally oriented, uninoculated Middlebrook and Cohn 7H10 agar that was incubated in the same incubator as clinical specimens grewM. abscessuswith a PFGE pattern that matched the pattern of the patient isolates. Cases ofM. abscessusinfection decreased to baseline after the hospital changed suppliers of mycobacterial media and cleaned the incubator.

Conclusions.

Although the source was never confirmed, our investigation suggests that this was a pseudo-outbreak ofM. abscessusinfection that resulted from contamination of mycobacterial cultures during incubation. Our findings emphasize the need for guidance on the disinfection of specimen incubators.

Longitudinal epiphyseal bracket

A longitudinal epiphyseal bracket (LEB) is a defect of the tubular bones and has been primarily described in the hands and feet, especially the proximal phalanges, metacarpals, and metatarsals. The LEB results from a defective C-shaped secondary ossification center that brackets the diaphysis and metaphysis, causing restricted longitudinal growth in these bones with resultant shortening and angular deformities. Deformities associated with metatarsal epiphyseal bracket include a short, broad metatarsal and medial deviation of the metatarsophalangeal joint (hallux varus deformity). Excision of the cartilaginous LEB has been proposed to prevent future soft tissue contractures and osseous deformities. The LEB has been associated with numerous syndromes including Rubinstein-Taybi syndrome, Cenani-Lenz syndactyly, isolated oligosyndactyly, and Nievergelt syndrome. We describe a two-month-old patient in whom plain film and MR imaging demonstrated bilateral bracketed first metatarsals with associated hallux varus deformities. Bilateral bracket excision was performed with excellent clinical results.

Metabolic and hemodynamic effects of CO2 pneumoperitoneum in a controlled hemorrhage model

BACKGROUND

Intracavity infusion of fibrin sealant-based agents, as a novel modality to control internal bleeding, is associated with an increase of pneumoperitoneum (PP) pressure. The safe limit of such increase has not been well defined in hypovolemic subjects. The purpose of this study was to evaluate the hemodynamic and metabolic effects of increasing PP pressure and to define the limits of carbon dioxide (CO2) insufflation in a controlled hemorrhage rat model.

METHODS

Ninety male rats (474 +/- 6 g, 37 degrees +/- 1 degrees C) were anesthetized, and mechanically ventilated. Animals were randomly distributed among 14 groups (n = 6-8) with an increasing amount of blood loss (0, 10, 15, and 17.5 mL/kg) and 15 minutes of CO2 insufflation at 0, 5, 10, and 15 mm Hg starting 15 minutes after hemorrhage, followed by desufflation. Mean arterial pressure (MAP), heart rate, and survival were recorded and arterial and venous blood samples were collected at baseline, at 15 minutes after hemorrhage, after insufflation, and after desufflation procedures to determine arterial blood gases and lactic acid levels.

RESULTS

In nonhemorrhaged animals, increasing PP pressure up to 15 mm Hg produced only transient changes in MAP and no increase in lactate level. A moderate hemorrhage (10 mL/kg) limited the safe abdominal pressure to 10 mm Hg with metabolic changes that were restored 15 minutes after desufflation. Higher PP pressure (15 mm Hg) at this hemorrhage level produced a significant decline in MAP (42%, p < 0.001) and progressive metabolic acidosis with a 2.1-fold increase (p < 0.01) in lactate level. The more severe hemorrhage (15 mL/kg) further reduced the limits of PP pressure such that 10 and 15 mm Hg resulted in a progressive decline of blood pressures (52% and 54%, respectively; p < 0.001) and severe metabolic acidosis as manifested by 3.3- and 3.1-fold rises in lactate levels, respectively. In the most severe hemorrhaged animals (17.5 mL/kg), the 50% mortality was primarily determined by the severity of the blood loss and the additional PP at 5 mm Hg had no significant impact.

CONCLUSION

The safe limit of PP pressurization with CO2 is dependent on the amount of blood loss. In this mechanically ventilated rat model, increasing the amount of blood loss from 0 to 15 mL/kg reduces the tolerable level of abdominal insufflation pressure from 15 mm Hg to 5 mm Hg. A 5-mm Hg PP pressure appears safe even in the most severely hemorrhaged animals.

Treatment of grade 4 renal stab wounds with absorbable fibrin adhesive bandage in a porcine model

PURPOSE

In a porcine model we evaluated the efficacy of the absorbable fibrin adhesive bandage and other novel fibrin products for treating major renal stab wounds.

MATERIALS AND METHODS

In commercial swine we produced an almost lethal, grade 4 renal stab wound via a 3.5 cm. sagittal, centrally located, through-and-through laceration. Each pig then received treatment in random fashion, including conventional oversewing of capsular defects with absorbable gelatin sponge and horizontal mattress sutures in 6, external absorbable fibrin adhesive bandage that was pressure held for 60 seconds in 6, external and internal absorbable fibrin adhesive bandage that was applied externally, inserted into the renal defect and pressure held for 60 seconds in 6, liquid fibrin sealant that was placed in the laceration and held for 60 seconds in 8, fibrin foam that was applied in the same manner as liquid fibrin in 5 and closing of the peritoneum over the lacerated kidney without further treatment in 6. Blood loss and time to hemostasis were recorded. Animals were sacrificed at 6 weeks to evaluate the injured renal unit.

RESULTS

Compared with conventional therapy the absorbable fibrin adhesive bandage applied externally alone or externally and internally resulted in significantly less bleeding and significantly less time to hemostasis (p <0.001). Liquid fibrin and fibrin foam did not reliably achieve hemostasis. Postoperatively computerized tomography and histological sectioning suggested that the absorbable fibrin adhesive bandage results in a stable, durable clot and healing is at least as successful as with conventional treatment.

CONCLUSIONS

The absorbable fibrin adhesive bandage appears to be a safe, rapid means of renal salvage after injury.

Does the absorbable fibrin adhesive bandage facilitate partial nephrectomy?

PURPOSE

To evaluate the ability of the absorbable fibrin adhesive bandage (AFAB), a prototype product comprising lyophilized fibrinogen and thrombin on a VicrylTM mesh backing, to seal the collecting system and control bleeding after partial nephrectomy.

MATERIALS AND METHODS

Growing female pigs (n = 18) underwent left nephrectomy and a 40% (by length) right lower pole partial nephrectomy. One of three treatments was immediately applied: Conventional-closure of the collecting system, ligation of visible segmental vessels, application of SurgicelTM with bolstering sutures to the renal capsule; AFAB-application of up to two 4 x 4-inch AFABs held under pressure for 60 seconds; Placebo-application of a hemostatically inert VicrylTM bandage, visually identical to the AFAB. Blood loss and ischemic and total operative times were recorded, and abdominal computerized tomography (CT) was performed on postoperative day 6. Animals were sacrificed at 6 weeks to evaluate the remaining renal mass histologically.

RESULTS

Compared with conventional therapy, use of the AFAB resulted in significantly less bleeding (13 versus 68 ml., p <0.001) and lower operative (7.2 versus 16.3 minutes, p <0.001) and ischemic times (3.4 versus 7.8 minutes, p <0.001). Estimated blood loss in the placebo bandage group was dramatically higher (357 ml., p <0.001). Postoperative CT and histological sectioning suggested that the AFAB produces a stable, durable clot and that healing is at least as successful as with conventional treatment.

CONCLUSION

Use of the AFAB facilitated performance of partial nephrectomy by reducing blood loss and ischemic and total operative times. The AFAB appears equivalent to conventional surgery in its ability to seal the collecting system.

Fibrin sealant foam sprayed directly on liver injuries decreases blood loss in resuscitated rats

OBJECTIVE

The majority of early trauma deaths are attributable to uncontrolled hemorrhage from truncal sites. A hemorrhage-control technique that reduced bleeding in the prehospital phase of treatment without requiring manual compression may improve the outcome of these patients. We conducted this preliminary study to determine whether an expanding fibrin sealant foam (FSF) would reduce bleeding from a severe liver injury even during resuscitation.

METHODS

Rats (n = 31; 291 +/- 5 g; 37.4 +/- 0.3 degrees C; mean +/- SEM), underwent a 60 +/- 5% excision of the median hepatic lobe. The animals received one of three treatments: (1) FSF, (2) immunoglobulin G placebo foam (IgGF), or (3) no treatment. All animals were resuscitated with 40 degrees C lactated Ringer's solution at 3.3 mL/ min/kg to a mean arterial pressure of 100 mm Hg. Total blood loss, mean arterial pressure, and resuscitation volume were recorded for 30 minutes. A qualitative measure of foam coverage and adherence to the cut liver edge was recorded.

RESULTS

The total blood loss was less (p < 0.01) in the FSF group (21.2 +/- 5.0 mL/kg) than in either IgGF (41.4 +/- 4.3 mL/kg) or the no treatment group (44.6 +/- 4.7 mL/kg), which did not differ. The resuscitation volume was not different. The amount of foam used in the treated groups, 9.1 +/- 1.0 g in the FSF group and 10.0 +/- 1.0 g in the IgGF group, did not differ. Survival for 30 minutes was not different among groups. There was no difference in the amount of cut liver covered by either foam, but the clots were more adherent (p < 0.05) in the FSF group than in the IgGF group.

CONCLUSION

In rats with a severe liver injury, spraying fibrin foam directly on the cut liver surface decreased blood loss when compared with placebo foam and no treatment. This pilot study suggests a future possible treatment for noncompressible truncal hemorrhage.

Intraoperative use of the absorbable fibrin adhesive bandage: long term effects

PURPOSE

The absorbable fibrin adhesive bandage (AFAB) reduces acute blood loss in experimental trauma models, but the effects on wound healing and subsequent function have heretofore not been investigated. Retropubic prostatectomy was selected to evaluate short and long term effects of using the AFAB intraoperatively.

MATERIALS AND METHODS

Dogs undergoing prostatectomy were randomly assigned to one of four treatments: CONTROL- sponges and manual pressure were applied after transecting the prostatic pedicles. Sponges were removed when the prostate was delivered. Vessels were isolated and ligated if bleeding continued after removal. AFAB- hemostatically active bandages were applied to the prostatic bed prior to sponges and pressure. Additional bandages were applied at the urethrovesical junction after completing the anastomosis. PLACEBO- visually identical (hemostatically inert) bandages were applied in an identical fashion. LIQUID SEALANT- concentrated thrombin and fibrinogen solution was applied to the vessels prior to sponges and pressure. Additional sealant solution was applied around the anastomosis.

RESULTS

Blood loss and time to achieve hemostasis were significantly less in the AFAB group compared with the other treatments. There were no differences in days to anastomotic integrity, continence, or intra-abdominal adhesions at necropsy six weeks later.

CONCLUSIONS

The AFAB can reduce surgery time and blood loss, with no decrement in wound healing or subsequent function.

Sumatriptan treatment for migraine in a health maintenance organization: economic, humanistic, and clinical outcomes

This study was undertaken to assess the impact of 12 months of sumatriptan therapy (6 mg subcutaneously) for migraine on health care use, health-related quality of life, productivity, patient satisfaction with the medication, and clinical efficacy in a health maintenance organization (HMO). One hundred forty-eight patients received open-label sumatriptan for 12 months for the treatment of migraine. Medical records were reviewed to obtain information on the frequency of migraine-related health care use during the 12 months before and during sumatriptan treatment. Patients completed questionnaires on their productivity at work, health-related quality of life, and satisfaction with medication at baseline and after 3, 6, and 12 months of sumatriptan treatment. For each migraine, patients recorded pain severity scores before and after taking sumatriptan and the time between dosing and onset of meaningful relief. Sumatriptan was associated with significant reductions in migraine-related use of general outpatient services, telephone calls, urgent care services, and emergency department visits (P < 0.05); a significant increase in the use of pharmacy services (P < 0.05); and significant and sustained improvements in health-related quality-of-life scores compared with baseline (P < 0.001). Patients lost significantly less time from work and were significantly more satisfied with sumatriptan compared with their usual therapy (P < 0.05). Two hours after dosing, 81% of patients experienced reduction of moderate or severe pain to mild or no pain, and 90% of all patients experienced meaningful relief of pain. The use of sumatriptan for 12 months in an HMO was associated with reductions in health care use and improved health-related quality of life, productivity, and patient satisfaction with medication.

Recruitment of lymphocytes during cutaneous delayed hypersensitivity in nonhuman primates is dependent on E-selectin and vascular cell adhesion molecule 1

Previous investigations of cutaneous delayed hypersensitivity (DHR) in humans and animals have demonstrated that lymphocyte recruitment from blood is temporally and spatially associated with the de novo, asynchronous expression of both vascular cell adhesion molecule 1 (VCAM-1) and E-selectin on dermal endothelium. In this study, DHR was induced in rhesus monkeys sensitized against tuberculin in order to investigate the contribution of E-selectin and VCAM-1 in lymphocyte recruitment to skin. Intravenous infusions of neutralizing doses of F(ab')2 fragments of murine antibodies to either E-selectin or VCAM-1 during the early inductive phases of DHR showed that murine IgG localized to dermal endothelium at the site of DHR in a pattern kinetically similar to the expression of each endothelial adhesion protein. Most importantly, the relative numbers of lymphocytes localized to the inflammatory site were significantly reduced in DHR modified with infusions of antibodies to either VCAM-1 or E-selectin, while the numbers of lymphocytes recruited to skin in the animal given F(ab')2 fragments of an irrelevant murine monoclonal antibody of the same isotype and at the same dose were not changed. Moreover, in individual animals, the relative inhibition achieved with a particular antibody was proportional to the magnitude of expression of the targeted adhesion protein. Therefore, both VCAM-1 and E-selectin are functionally relevant in the genesis of cutaneous DHR, and each appears to contribute to lymphocyte recruitment in relation to its relative degree of expression in any one particular animal.

Elevated vascular cell adhesion molecule-1 in AIDS encephalitis induced by simian immunodeficiency virus

AIDS encephalitis is a common sequela to HIV-1 infection in humans and simian immunodeficiency virus (SIVmac) infection in macaques. Although lentiviral-infected macrophages comprise parenchymal inflammatory infiltrates in affected brain tissue, the mechanisms responsible for leukocyte trafficking to the central nervous system in AIDS are unknown. In this study, we investigated the expression of various endothelial-derived leukocyte adhesion proteins in SIVmac-induced AIDS encephalitis. Encephalitic brains from SIVmac-infected macaques, but not uninflamed brains from other SIVmac-infected animals, were found to express abundant vascular cell adhesion molecule-1 (VCAM-1) protein on the majority of arteriolar, venular, and capillary endothelial cells. Soluble VCAM-1 concentrations in cerebrospinal fluid (CSF) from encephalitic animals were increased approximately 20-fold above those from animals without AIDS encephalitis. Expression of other endothelial-related adhesion molecules, including E-selectin, P-selectin, and intercellular adhesion molecule-1 (ICAM-1), was not uniformly associated with AIDS encephalitis. Thus, the presence of VCAM-1 in both brain and CSF was uniformly associated with SIVmac-induced disease of the central nervous system, and this expression may, at least in part, influence monocyte and lymphocyte recruitment to the central nervous system during the development of AIDS encephalitis. Moreover, measurement of soluble VCAM-1 in CSF may assist in the clinical assessment of animals or people with AIDS.

Mechanisms of experimental cancer cachexia. Interaction between mononuclear phagocytes and colon-26 carcinoma and its relevance to IL-6-mediated cancer cachexia

In a recent report we showed that IL-6 is an important mediator of experimental cancer cachexia in the colon-26 (C-26) tumor system. In culture, on a per cell basis, C-26.IVX cell line (which develops tumors and induces severe cachexia of syngeneic hosts) produces up to 60-fold less IL-6 than single cell suspensions prepared from freshly excised tumors. In this study, the mechanism behind this observation was investigated. Analysis of the cellular composition of progressing C-26 tumors indicated they contained up to 6% of macrophages. T cells, B cells, and granulocytes were not detected in the tumors. Because C-26.IVX line grown in vitro contained no macrophages, the possibility that macrophage products may augment IL-6 synthesis by the tumor cells was tested. Indeed, IL-1 beta in a dose-dependent manner and at picogram amounts could potentiate IL-6 production by the C-26 cell line. The presence of high affinity receptors for IL-1 on the C-26.IVX cell line was established. These cells expressed approximately 1500 IL-1 sites per cell with a dissociation constant of approximately 20 pM. Next, we attempted to mimic the situation in vivo by coculture of C-26.IVX cells with syngeneic peritoneal macrophages and found that this condition gives rise to an augmented IL-6 production similar to that observed with in vivo derived tumor cells or rIL-1 beta-treated C-26.IVX cells. Furthermore, anti-IL-1 type I receptor antibody completely blocked C-26.IVX IL-6 production induced by either rIL-1 beta or by peritoneal macrophages. Taken together, these data suggest a pathway of IL-6 production by C-26 tumors that involves a cellular interaction between IL-1R-expressing tumor cells and host-derived macrophages. The results also suggest that this interaction significantly contributes to cachectic events endured by the tumor-bearing host.

Mechanisms of experimental cancer cachexia. Interaction between mononuclear phagocytes and colon-26 carcinoma and its relevance to IL-6-mediated cancer cachexia

In a recent report we showed that IL-6 is an important mediator of experimental cancer cachexia in the colon-26 (C-26) tumor system. In culture, on a per cell basis, C-26.IVX cell line (which develops tumors and induces severe cachexia of syngeneic hosts) produces up to 60-fold less IL-6 than single cell suspensions prepared from freshly excised tumors. In this study, the mechanism behind this observation was investigated. Analysis of the cellular composition of progressing C-26 tumors indicated they contained up to 6% of macrophages. T cells, B cells, and granulocytes were not detected in the tumors. Because C-26.IVX line grown in vitro contained no macrophages, the possibility that macrophage products may augment IL-6 synthesis by the tumor cells was tested. Indeed, IL-1 beta in a dose-dependent manner and at picogram amounts could potentiate IL-6 production by the C-26 cell line. The presence of high affinity receptors for IL-1 on the C-26.IVX cell line was established. These cells expressed approximately 1500 IL-1 sites per cell with a dissociation constant of approximately 20 pM. Next, we attempted to mimic the situation in vivo by coculture of C-26.IVX cells with syngeneic peritoneal macrophages and found that this condition gives rise to an augmented IL-6 production similar to that observed with in vivo derived tumor cells or rIL-1 beta-treated C-26.IVX cells. Furthermore, anti-IL-1 type I receptor antibody completely blocked C-26.IVX IL-6 production induced by either rIL-1 beta or by peritoneal macrophages. Taken together, these data suggest a pathway of IL-6 production by C-26 tumors that involves a cellular interaction between IL-1R-expressing tumor cells and host-derived macrophages. The results also suggest that this interaction significantly contributes to cachectic events endured by the tumor-bearing host.