John MacVicar

The effectiveness and risks of fluoroscopically guided cervical transforaminal injections of steroids: a systematic review with comprehensive analysis of the published data.

OBJECTIVE To determine the effectiveness and risks of fluoroscopically guided cervical transforaminal injection of corticosteroids in the treatment of radicular pain. DESIGN Systematic review of the literature with comprehensive analysis of the published data. INTERVENTIONS Three reviewers with formal training in evidence-based medicine searched the literature on fluoroscopically guided cervical transforaminal injection of steroids (CTFIS). Each reviewer independently assessed the methodology of studies found and appraised the quality of the evidence presented. OUTCOME MEASURES The primary outcome assessed was relief of radicular pain. Other outcomes such as reduction in surgery rate and complications were noted if reported. The evidence on each outcome was appraised in accordance with the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system of evaluating evidence. RESULTS The searches yielded 16 primary publications on effectiveness. Available evidence, derived mainly from observational studies, suggests that approximately 50% of patients experience 50% relief of radicular pain for at least 4 weeks after CTFIS, and the intervention may have surgery-sparing effects. The literature also contains 21 articles with primary reports of serious complications, including 13 deaths and many catastrophic neurological injuries. The evidence of pain-relieving effects, of surgery-sparing effects, and of risks of CTFIS were all rated as of very low quality according to the GRADE system. CONCLUSIONS In patients with cervical radicular pain, fluoroscopically guided CTFIS may be effective in easing pain and reducing need for surgery. However, the evidence of effectiveness is of very low quality, and the benefits of the procedure are compromised by the risks of serious complications.

Cervical Medial Branch Radiofrequency Neurotomy in New Zealand

OBJECTIVE The objective of this study was to determine the effectiveness of cervical medial branch radiofrequency neurotomy (RFN) performed by two practitioners trained according to rigorous guidelines. DESIGN The study was designed as a prospective, outcome study of consecutive patients with chronic neck pain treated in a community setting. INTERVENTIONS A total of 104 patients, selected on the basis of complete relief of pain following controlled, diagnostic, medial branch blocks, were treated with RFN according to the guidelines of the International Spine Intervention Society. OUTCOME MEASURES Successful outcome was defined as complete relief of pain, or at least 80% relief, for at least 6 months, with complete restoration of activities of daily living, no need for any further health care, and return to work. Patients who failed to meet any of these criteria were deemed to have failed treatment. RESULTS In the two practices, 74% and 61% of patients achieved a successful outcome. Relief lasted 17-20 months from the first RFN, and 15 months for repeat treatments. Allowing for repeat treatment, patients maintained relief for a median duration of 20-26 months, with some 60% still having relief at follow-up. CONCLUSION Cervical RFN can be very effective when performed in a rigorous manner in appropriately selected patients. Chronic neck pain, mediated by the cervical medial branches, can be temporarily, but completely, relieved and patients fully restored to desired activities of daily living, if treated with RFN.

Lumbar medial branch radiofrequency neurotomy in New Zealand.

OBJECTIVE This study aims to determine the effectiveness of lumbar medial branch radiofrequency neurotomy (RFN) performed by two practitioners trained according to rigorous guidelines. DESIGN Prospective, outcome study of consecutive patients with chronic back pain treated in a community setting. INTERVENTIONS A total of 106 patients, selected on the basis of complete relief of pain following controlled, diagnostic, medial branch blocks, were treated with RFN according to the guidelines of the International Spine Intervention Society. OUTCOME MEASURES Successful outcome was defined as complete relief of pain for at least 6 months, with complete restoration of activities of daily living, no need for any further health care, and return to work. Patients who failed to meet any of these criteria were deemed to have failed treatment. RESULTS In the two practices, 58% and 53% of patients achieved a successful outcome. Relief lasted 15 months from the first RFN and 13 months for repeat treatments. Allowing for repeat treatment, patients maintained relief for a median duration of 17-33 months, with some 70% still having relief at follow-up. CONCLUSION Lumbar RFN can be very effective when performed in a rigorous manner in appropriately selected patients. Chronic back pain, mediated by the lumbar medial branches, can be stopped and patients fully restored to normal living, if treated with RFN.

The Pain of Vertebral Compression Fractures Can Arise in the Posterior Elements

OBJECTIVES To describe and test a model to explain the biomechanical basis for persistent pain after compression fractures of the vertebral body. METHODS The biomechanics model was derived axiomatically from a consideration of the anatomy of vertebral column when affected by compression fractures. Proof of principle was provided by performing controlled diagnostic blocks in six patients. RESULTS The biomechanics model shows that the posterior elements of the vertebral column must subluxate cephalad or caudad in response to deformity of a vertebral body. The model implies that pain may arise from the posterior elements, and predicts that anesthetizing the posterior elements should relieve the pain of compression fractures. Six cases are described in which controlled medial branch blocks relieved the pain of compression fractures of thoracic or lumbar vertebral bodies. CONCLUSIONS In some patients with vertebral compression fractures, the pain may arise from posterior elements and not the fracture itself. This phenomenon has implications for the interpretation of the outcomes of vertebroplasty in both the active and control arms of sham-controlled studies.

Fluoroscopically Guided Diagnostic and Therapeutic Intra-Articular Sacroiliac Joint Injections: A Systematic Review.

OBJECTIVE To assess the validity of fluoroscopically guided diagnostic intra-articular injections of local anesthetic and effectiveness of intra-articular steroid injections in treating sacroiliac joint (SIJ) pain. DESIGN Systematic review. INTERVENTIONS Ten reviewers independently assessed 45 publications on diagnostic validity or effectiveness of fluoroscopically guided intra-articular SIJ injections. OUTCOME MEASURES For diagnostic injections, the primary outcome was validity; for therapeutic injections, analgesia. Secondary outcomes were also described. RESULTS Of 45 articles reviewed, 39 yielded diagnostic data on physical exam findings, provocation tests, and SIJ injections for diagnosing SIJ pain, and 15 addressed therapeutic effectiveness. When confirmed by comparative local anesthetic blocks with a high degree of pain relief, no single physical exam maneuver predicts response to diagnostic injections. When at least three physical exam findings are present, sensitivity, and specificity increases significantly. The prevalence of SIJ pain is likely 20-30% among patients that have suspected SIJ pain based on history and physical examination. This estimate may be higher in certain subgroups such as the elderly and fusion patients. Two randomized controlled trials and multiple observational studies supported the effectiveness of therapeutic sacroiliac joint injections. CONCLUSIONS Based on this literature, it is unclear whether image-guided intra-articular diagnostic injections of local anesthetic predict positive responses to therapeutic agents. The overall quality of evidence is moderate for the effectiveness of therapeutic SIJ injections.

Diagnosis and Treatment of Posterior Sacroiliac Complex Pain: A Systematic Review with Comprehensive Analysis of the Published Data

OBJECTIVE To assess the evidence on the validity of sacral lateral branch blocks and the effectiveness of sacral lateral branch thermal radiofrequency neurotomy in managing sacroiliac complex pain. DESIGN Systematic review with comprehensive analysis of all published data. INTERVENTIONS Six reviewers searched the literature on sacral lateral branch interventions. Each assessed the methodologies of studies found and the quality of the evidence presented. OUTCOME MEASURES The outcomes assessed were diagnostic validity and effectiveness of treatment for sacroiliac complex pain. The evidence found was appraised in accordance with the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system of evaluating scientific evidence. RESULTS The searches yielded two primary publications on sacral lateral branch blocks and 15 studies of the effectiveness of sacral lateral branch thermal radiofrequency neurotomy. One study showed multisite, multidepth sacral lateral branch blocks can anesthetize the posterior sacroiliac ligaments. Therapeutic studies show sacral lateral branch thermal radiofrequency neurotomy can relieve sacroiliac complex pain to some extent. The evidence of the validity of these blocks and the effectiveness of this treatment were rated as moderate in accordance with the GRADE system. CONCLUSIONS The literature on sacral lateral branch interventions is sparse. One study demonstrates the face validity of multisite, multidepth sacral lateral branch blocks for diagnosis of posterior sacroiliac complex pain. Some evidence of moderate quality exists on therapeutic procedures, but it is insufficient to determine the indications and effectiveness of sacral lateral branch thermal radiofrequency neurotomy, and more research is required.

The mild® Procedure: A Systematic Review of the Current Literature

OBJECTIVES This studys objective was to determine if the literature supports use of the Minimally Invasive Lumbar Decompression (mild®) procedure (Vertos Medical, Aliso Viejo, CA, USA) to reduce pain and improve function in patients with symptomatic degenerative lumbar spinal stenosis. DESIGN/SETTINGS The study was designed as an evidence-based review of available data. Studies were identified from PubMed, Embase, and the Cochrane Library. Articles were evaluated using the Grading of Recommendations Assessment, Development and Evaluation Working Group system. Results were compiled assessing short- (4-6 weeks), medium- (3-6 months), and long-term (>1 year) outcomes. The primary outcomes evaluated were pain, measured by the visual analog scale (VAS), and function, measured by the Oswestry Disability Index (ODI). Secondary outcomes included pain and patient satisfaction, measured by the Zurich Claudication Questionnaire, adverse effects/complications, and changes in utilization of co-interventions. RESULTS The literature search revealed one randomized controlled trial (RCT) and 12 other studies (seven prospective cohort, four retrospective, and one case series) that provided information on the use of mild® in patients with degenerative lumbar spinal stenosis. All studies showed statistically significant improvements in VAS and ODI scores at all time frames compared with preprocedure levels; the RCT showed improvement over controls. Categorical data were not provided; thus, the proportion of patients who experienced minimal clinically meaningful outcomes is unknown. CONCLUSION The current body of evidence addressing mild® is of low quality. High-quality studies that are independent of industry funding and provide categorical data are needed to clarify the proportions of patients who benefit from mild® and the degree to which these patients benefit. Additional data at up to 2 years are needed to determine the overall utility of the procedure.

Appropriate Use Criteria for Fluoroscopically Guided Diagnostic and Therapeutic Sacroiliac Interventions: Results from the Spine Intervention Society Convened Multispecialty Collaborative

Objective To provide an overview of a multisociety effort to formulate appropriate use criteria for image-guided injections and radiofrequency procedures in the diagnosis and treatment of sacroiliac joint and posterior sacroiliac complex pain. Methods The Spine Intervention Society convened a multisociety effort to guide physicians and define for payers the appropriate use of image-guided injections and radiofrequency procedures. An evidence panel was established to write systematic reviews, define key terms and assumptions, and develop clinical scenarios to be addressed. The rating panel considered the evidence presented in the systematic reviews, carefully reviewed the definitions and assumptions, and rated the clinical scenarios. Final median ratings, in combination with the level of agreement, determined the final ratings for the appropriate use of sacroiliac injections and radiofrequency neurotomy. Results More than 10,000 scenarios were addressed in the appropriate use criteria and are housed within five modules in the portal, available on the Spine Intervention Society website: Module 1: Clinical Indications and Imaging; Module 2: Anticoagulants; Module 3: Timing of Injections; Module 4: Number of Injections; and Module 5: Lateral Branch Radiofrequency Neurotomy. Within several of these modules, several issues of interest are identified and discussed. Conclusions Physicians and payers can access the appropriate use criteria portal on the Spine Intervention Societys website and select specific clinical indications for a particular patient in order to learn more about the appropriateness of the intervention(s) under consideration.

High-pressure discography may injure discs

We thank Engel et al. and Koetsier et al. for their interest in our study. The ante hoc study design planned for head-to-head statistical comparisons between primary outcomes: by year 10, there were significant differences between the primary clinical outcomes of patients with punctured or injected discs and those of the controls, with a statistically significant difference defined as p<.05. The authors of the letter have artificially juggled the data post hoc to produce an isolated comparison demonstrating a minor confidence interval overlap wherein a threefold difference is minimized. The ante hoc primary analysis is necessarily a stronger and more confident analysis. This is a most basic tenet of biostatistics. Adverse outcomes were found in every single primary ante hoc comparison—a powerful unidirectional difference across the board in all study variables. Statistical analysis demonstrated that for each of these variables, the difference was statistically significant and was not a statistical “trend.” The “chance” of a random unidirectional and adverse outcome in the discography group is exceedingly small. The authors of the letter also inaccurately state that intradiscal pressure levels used during the discography in our study reached 100 psi above opening pressure. In fact, the injection had value set at 100 psi at the pressure relief valve (at the syringe level), and the most any subject received was 70–80 psi above the opening pressure (commonly about 20 psi). No patient was subjected to 100 psi above opening pressure. These tests were done in the 1990s when levels of 100 psi above opening pressure values were routinely used. We examined the outcomes of discs in our data set that had received a psi of 50 or more and compared these with discs with lower end pressures to determine if higher pressures resulted in greater, single disc–specific, adverse events (eg, patient requiring L4–L5 discectomy). After controlling for baseline disc degeneration, we found that the data trended in the opposite direction: discs with end pressures <50 psi were more likely to demonstrate accelerated degeneration after discography, greater loss of signal and disc height, and more frequent herniation. Finally, the argument supporting a 50 psi limit has been purported by Dr Nikolai Bogduk and originated in an early study by Derby et al [1]. It should be noted that the study designers, discographers, test subjects, and authors were in many cases the same individuals in the study reported by Derby et al [1]. This study, the primary source for a 50 psi limit of pressurization, is severely flawed and cannot be seriously considered. Lastly, the authors of the letter point out the fact that some of our study subjects were asymptomatic volunteers. According to Sackett and Haynes, the Journal of the American Medical Association, and the British Medical Journal guidelines for examining diagnostic tests, the starting point of test examination very often should be subjects known not to have the disease in question. This was our starting point for examining provocative lumbar discography as a test for discogenic low back pain. It failed to pass even the lowest bar of validity.

Not All Injections Are the Same

To the Editor: In metaphorical terms, a problem arises when good apples are pooled with bad apples; they all get tarred with the same brush. This principle applies when all studies pertaining to spinal injections of steroids are pooled, as if they are all equal. Subsequently, the lay press publicizes sweeping conclusions such as “injecting any liquid, even plain saline solution, works just as well.”1 Such statements bring all injections into disrepute. Admirably, Bicket et al.2 used an ingenious statistical exercise to explore the conjecture that epidural injections of other agents are not fair controls as epidural injections of steroids. However, in their exploration, they pooled data on cervical and lumbar injections, on image-guided injections and blind injections, and on interlaminar, caudal, and transforaminal injections; they even included studies that did not involve steroids. Given that these various targets and techniques differ with respect to pathology, anatomy, technical accuracy, and evidence base, such pooling might not be legitimate, and at least clouds the true picture. Prominent among the studies analyzed is that of Ghahreman et al.3 which, indeed, the authors rank as rigorous. In the statistical analysis, this study stands out as an outlier; but it is also different in other respects. It is one of the few studies included in the review that used transforaminal injections, and it is the only study that actually addressed prospectively the very question being explored by the meta-analysis. In that regard, its results happen to contradict the conclusions of the review. It showed that the efficacy of transforaminal injection of steroid is significantly greater than that of transforaminal injection of nonsteroid. The authors of the review have referred to a conclusion that detecting a difference between treatment and control groups would not be practical but have not stated that this conclusion related specifically to long-term (12 months) outcomes. It would have been more courteous, and more informative, had the authors stratified their analysis by region and by technique. Their conclusions might still apply to classical, blind epidural injections, but they would not apply to lumbar transforaminal injections. Lumbar transforaminal injection of steroids is significantly more often effective than transforaminal injection of either local anesthetic or saline, and intramuscular injection of either steroids or saline, and by the same magnitude in all cases. It may be that these data could be overturned by future studies, but at present, they are the only direct data on this procedure. Those data defy the sweeping generalizations of the review, which are sensationalized by the lay press, and which serve the purpose of those who wish to deny reimbursement for epidural injections. Meta-analysis of circumstantial evidence does not constitute proof; is not a substitute for well-designed controlled trials that address the issue. It serves only to raise an intriguing proposition worthy of studies that prospectively test it. In this dural incision. Renal blood flow was similarly trended using laser-Doppler probes placed surgically against the renal capsule. Red cell flux monitoring was plotted against cerebral and renal perfusion pressure respectively as a definitive standard pressure autoregulation curve. The aim of the study was to test the accuracy of separately measured metrics of dynamic vascular reactivity derived from near-infrared spectroscopy: the hemoglobin volume index describing cerebral vascular reactivity and the renovascular reactivity index to describe vascular reactivity in the kidney. Although not the primary aim of that study, it was observed in some animals that renal blood flow fell during hemorrhagic shock before any change in arterial blood pressure occurred. Although, cardiac output was not directly monitored, these findings of reduced renal blood flow despite no change in blood pressure can be explained only by a reduced cardiac output. This was demonstrated by the example data shown in the figures of the article. Thus, these findings support our contention that renal blood flow is dependent on both blood flow (cardiac output or cardiopulmonary bypass) and blood pressure as we state in our editorial.