Intraosseous Basivertebral Nerve Radiofrequency Ablation for the Treatment of Vertebral Body Endplate Low Back Pain: Current Evidence and Future Directions.

Recently, basivertebral nerve (BVN) radiofrequency ablation has been developed for the treatment of chronic low back pain (CLBP) thought to arise from the vertebral body endplates (VEPs). This review describes the relevant neuroanatomy and pathobiology of VEP degeneration and injury, imaging correlates of presumed VEP pain, randomized controlled trials performed, appropriate patient selection, and safety. Anatomic, histological, and clinical evidence supports the concept of the VEP as a source of CLBP and the nociceptive role of the BVN. BVN radiofrequency ablation appears to be an effective treatment for a subset of patients with CLBP and evidence of Modic change types 1 and 2 in the L3 to S1 VEPs who have failed to respond to conservative treatment. However, all studies performed to date have been industry sponsored, and future non-industry-funded trials will be needed to confirm these results.

The Use of Contrast Agents in Interventional Pain Procedures: A Multispecialty and Multisociety Practice Advisory on Nephrogenic Systemic Fibrosis, Gadolinium Deposition in the Brain, Encephalopathy After Unintentional Intrathecal Gadolinium Injection, and Hypersensitivity Reactions.

This Practice Advisory presents a comprehensive and evidence-based set of position statements and recommendations for the use of contrast media in interventional pain procedures. The advisory was established by an international panel of experts under the auspices of 11 multinational and multispecialty organizations based on a comprehensive review of the literature up to December 31, 2019. The advisory discusses the risks of using gadolinium-based contrast agents. These include nephrogenic systemic fibrosis, gadolinium brain deposition/retention, and encephalopathy and death after an unintentional intrathecal gadolinium injection. The advisory provides recommendations on the selection of a specific gadolinium-based contrast agent in patients with renal insufficiency, those who had multiple gadolinium-enhanced magnetic resonance imaging examinations, and in cases of paraspinal injections. Additionally, recommendations are made for patients who have a history of mild, moderate, or severe hypersensitivity reactions to contrast medium.

Synovial Cysts Confounding Access to the Dorsal S1 Neural Foramen in Transforaminal Epidural Steroid Injections.

OBJECTIVES: The S1 dorsal foramen is the route for 30% of lumbar transforaminal epidural injections; it is therefore important to identify structures impeding S1 foraminal access. The study objective was to characterize the imaging findings, prevalence, and anatomic origin of synovial cysts presenting within the S1 neural foramen. METHODS: A case series (N = 14) established imaging characteristics of S1 synovial cysts. Imaging studies of 400 patients undergoing epidural injections were reviewed for lesions compromising S1 foraminal access. Cadaveric dissections defined the relationship of the inferior recess of the L5-S1 facet to the S1 dorsal foramen. RESULTS: Elderly patients (mean age = 76) exhibited S1 synovial cysts. Synovial cysts were typically 1-2 cm in diameter, hyperintense on sagittal T2 weighted magnetic resonance images (MRIs), fluid-density on computed tomography, and dorsal to the S1 spinal nerve. Sixty percent of cysts exhibited complex MRI signal characteristics (thick wall, internal structure). Tarlov cysts, in contrast, were larger, lobular, and exhibited pure fluid intensity. Lesions impeded access to the S1 dorsal foramina in 5% of reviewed imaging studies (16 Tarlov cysts, three synovial cysts, one conjoint S1-S2 nerve root). The multifidus muscle was interposed between the L5-S1 facet inferior recess and the S1 dorsal foramen on dissection specimens; severe atrophy of the ipsilateral multifidus was noted on imaging in 17/18 synovial cysts. CONCLUSIONS: The S1 neural foramina should be inspected on sagittal MRI, when available, for confounding lesions before performing S1 epidural injections. Tarlov cysts are more common than synovial cysts; the latter are seen in elderly patients with severe multifidus atrophy.

Unilateral Epidural Targeting of Resiniferatoxin Induces Bilateral Neurolysis of Spinal Nociceptive Afferents.

OBJECTIVE: This study modeled image-guided epidural drug delivery to test whether intraprocedural distribution of pre-injected contrast reliably predicts the neuroanatomical reach of resiniferatoxin-mediated nociceptive neurolysis. METHODS: Swine (N = 12) received unilateral L4-S2 computed tomography fluoroscopy injections by a blinded neuroradiologist; 0.25 mL of contrast was pre-injected to confirm dorsal periganglionic targeting, followed by a 0.5-mL injection of 5 µg of resiniferatoxin/Tween80 or vehicle control. Epidural contrast distribution was graded according to maximum medial excursion. Spinal cord substance P immunostaining quantified the magnitude and anatomical range of resiniferatoxin activity. RESULTS: Periganglionic injection was well tolerated by all animals without development of neurological deficits or other complications. Swine were a suitable model of human clinical spinal intervention. The transforaminal approach was used at all L4 and 50% of L5 segments; the remaining segments were approached by the interlaminar route. All injections were successful with unilateral contrast distribution for all resiniferatoxin injections (N = 28). Immunohistochemistry showed bilateral ablation of substance P+ fibers entering the spinal cord of all resiniferatoxin-treated segments. The intensity of substance P immunostaining in treated segments fell below the lower 99% confidence interval of controls, defining the knockout phenotype. Substance P knockout occurred over a narrow range and was uncorrelated to the anatomical distribution of pre-injected contrast. CONCLUSIONS: Periganglionic resiniferatoxin/Tween80 induced bilateral ablation of spinal cord substance P despite exclusively unilateral targeting. These data suggest that the location of pre-injected contrast is an imperfect surrogate for the neuroanatomical range of drugs delivered to the dorsal epidural compartment that may fail to predict contralateral drug effects.

Human interleukin-10 delivered intrathecally by self-complementary adeno-associated virus 8 induces xenogeneic transgene immunity without clinical neurotoxicity in swine.

INTRODUCTION: Intrathecal interleukin (IL)-10 delivered by plasmid or viral gene vectors has been proposed for clinical testing because it is effective for chronic pain in rodents, is a potential therapeutic for various human diseases, and was found to be nontoxic in dogs, when the human IL-10 ortholog was tested. However, recent studies in swine testing porcine IL-10 demonstrated fatal neurotoxicity. The present study aimed to deliver vector-encoded human IL-10 in swine, measure expression of the transgene in cerebrospinal fluid and monitor animals for signs of neurotoxicity. RESULTS: Human IL-10 levels peaked 2 weeks after vector administration followed by a rapid decline that occurred concomitant with the emergence of anti-human IL-10 antibodies in the cerebrospinal fluid and serum. Animals remained neurologically healthy throughout the study period. CONCLUSIONS: The findings of the present study suggest that swine are not idiosyncratically sensitive to intrathecal IL-10 because, recapitulating previous reports in dogs, they suffered no clinical neurotoxicity from the human ortholog. These results strongly infer that toxicity of intrathecal IL-10 in large animal models was previously overlooked because of a species mismatch between transgene and host. The present study further suggests that swine were protected from interleukin-10 by a humoral immune response against the xenogeneic cytokine. Future safety studies of IL-10 or related therapeutics may require syngeneic large animal models.

The Effect of Epidural Steroid Injections on Bone Mineral Density and Vertebral Fracture Risk: A Systematic Review and Critical Appraisal of Current Literature.

Objective: The aim of this paper is to review the available literature investigating the effect of epidural steroid injections (ESIs) on bone mineral density (BMD) and vertebral fracture risk. Study design: Systematic review of current literature. Methods: The sources of the data were PubMed, Embase, Cochrane, and Scopus. Papers included in the review were original research articles in peer-reviewed journals. Results: A total of 7,233 patients (eight studies) with a mean age ranging between 49 and 74 years and an average follow-up between six and 60 months were studied. Steroids that were used included triamcinolone, dexamethasone, and methylprednisolone (MP), with a mean number of injections ranging from one to 14.7 and an average cumulative dose in MP equivalents between 80 and 8,130 mg. Epidural steroids were associated with significantly decreased BMD in four out of six included studies, and with increased risk of vertebral fracture in one out of two included studies. Significant reductions in BMD were associated with a cumulative MP dose of 200 mg over a one-year period and 400 mg over three years, but not in doses of less than 200 mg of MP equivalents for postmenopausal women and at least 3 g for healthy men. The risk of osteopenia and osteoporosis was lower in patients who were receiving anti-osteoporotic medication during the treatment course. Conclusions: ESIs should be recommended with caution, especially in patients at risk for osteoporotic fractures, such as women of postmenopausal age. Anti-osteoporotic medication might be considered prior to ESI.

Fatal Meningitis in Swine after Intrathecal Administration of Adeno-associated Virus Expressing Syngeneic Interleukin-10.

Interleukin-10 (IL-10) delivered by intrathecal (i.t.) gene vectors is a candidate investigational new drug (IND) for several chronic neurological disorders such as neuropathic pain. We performed a preclinical safety study of IL-10. A syngeneic large animal model was used delivering porcine IL-10 (pIL-10) to the i.t. space in swine by adeno-associated virus serotype 8 (AAV8), a gene vector that was previously found to be nontoxic in the i.t. space. Unexpectedly, animals became ill, developing ataxia, seizures, and an inability to feed and drink, and required euthanasia. Necropsy demonstrated lymphocytic meningitis without evidence of infection in the presence of normal laboratory findings for body fluids and normal histopathology of peripheral organs. Results were replicated in a second animal cohort by a team of independent experimenters. An extensive infectious disease and neuropathology workup consisting of comprehensive testing of tissues and body fluids in a specialized research veterinary pathology environment did not identify a pathogen. These observations raise the concern that i.t. IL-10 therapy may not be benign, that previously used xenogeneic models testing the human homolog of IL-10 may not have been sensitive enough to detect toxicity, and that additional preclinical studies may be needed before clinical testing of IL-10 can be considered.

Relative Conspicuity of Gadolinium-Based Contrast Agents in Interventional Pain Procedures.

Objective: To assess the relative radiographic conspicuity of gadolinium-based contrast agents (GBCAs) that may be used in spinal injection procedures when iodine-based contrast agents are contraindicated. Methods: Eight GBCAs and three iodinated agents of varying iodine concentrations were radiographed under conditions representative of lumbar spinal injections at four kilovoltage peak (kVp) values. Radiographic contrast of each agent was measured as the percent pixel value difference with respect to background. Results: Gadobutrol (Gadovist, 1 mM/mL) had the highest radiographic contrast among the gadolinium agents tested. Measured radiographic contrast correlated with the molar concentration of gadolinium. Gadobutrol radiographic contrast lies between the contrast of iohexol concentrations of 240 and 140 mgI/mL. All agents have decreasing contrast as kVp increases, but GBCAs decrease less than iodine-based agents. Conclusions: Gadobutrol is the GBCA with the greatest conspicuity for use in spinal injection procedures. It also has the highest molar concentration of gadolinium, and potential neural toxicity from intrathecal delivery must be considered.

Science to Practice: What Causes Arterial Infarction in Transforaminal Epidural Steroid Injections, and Which Steroid Is Safest?

Transforaminal epidural steroid injections (TFESIs) are associated with rare but devastating neurologic complications. Every published case has been associated with a particulate steroid suspension, and the presumed but not proven mechanism is embolization and occlusion of end arterioles. Through an in vivo murine model and in vitro experiments on human red blood cells (RBCs), the study by Laemmel et al (1) in this issue of Radiology elucidates the potential mechanisms for steroid-induced vascular compromise. Unlike dexamethasone (a nonparticulate steroid solution), saline, and the particulate steroid cortivazol, other particulate steroids (prednisolone, methylprednisolone, and triamcinolone) caused often immediate and complete cessation of capillary blood flow, with RBC (not steroid particle) aggregates and alteration of RBC morphologic structure into spiculated RBCs. Thus, the study strengthens evidence in support of the higher safety profile in TFESI for dexamethasone, the nonparticulate and U.S. Food and Drug Administration-recommended steroid of choice, compared with particulate steroids. The results should not be considered proof that cortivazol has not or could not cause neurologic infarction during a TFESI. Rather, experiments such as those by Laemmel et al should foster more research, particularly in the arena of novel therapeutic agents (nonparticulate steroids and nonsteroidal drugs alike).

Uncommon Manifestations of Intervertebral Disk Pathologic Conditions.

Beyond the familiar disk herniations with typical clinical features, intervertebral disk pathologic conditions can have a wide spectrum of imaging and clinical manifestations. The goal of this review is to illustrate and discuss unusual manifestations of intervertebral disk pathologic conditions that radiologists may encounter, including disk herniations in unusual locations, those with atypical imaging features, and those with uncommon pathophysiologic findings. Examples of atypical disk herniations presented include dorsal epidural, intradural, symptomatic thoracic (including giant calcified), extreme lateral (retroperitoneal), fluorine 18 fluorodeoxyglucose-avid, acute intravertebral (Schmorl node), and massive lumbar disk herniations. Examples of atypical pathophysiologic conditions covered are discal cysts, fibrocartilaginous emboli to the spinal cord, tiny calcified disks or disk-level spiculated osteophytes causing spinal cerebrospinal fluid (CSF) leak and intracranial hypotension, and pediatric acute calcific discitis. This broad gamut of disease includes a variety of sizes of disk pathologic conditions, from the tiny (eg, the minuscule calcified disks causing high-flow CSF leaks) to the extremely large (eg, giant calcified thoracic intradural disk herniations causing myelopathy). A spectrum of clinical acuity is represented, from hyperacute fibrocartilaginous emboli causing spinal cord infarct, to acute Schmorl nodes, to chronic intradural herniations. The entities included are characterized by a range of clinical courses, from the typically devastating cord infarct caused by fibrocartilaginous emboli, to the usually spontaneously resolving pediatric acute calcific discitis. Several conditions have important differential diagnostic considerations, and others have relatively diagnostic imaging findings. The pathophysiologic findings are well understood for some of these entities and poorly defined for others. Radiologists' knowledge of this broad scope of unusual disk disease is critical for accurate radiologic diagnoses. Online supplemental material is available for this article. (©)RSNA, 2016.

Immediate Adverse Events in Interventional Pain Procedures: A Multi-Institutional Study.

SETTING: Interventional procedures directed toward sources of pain in the axial and appendicular musculoskeletal system are performed with increasing frequency. Despite the presence of evidence-based guidelines for such procedures, there are wide variations in practice. Case reports of serious complications such as spinal cord infarction or infection from spine injections lack appropriate context and create a misleading view of the risks of appropriately performed interventional pain procedures. OBJECTIVE: To evaluate adverse event rate for interventional spine procedures performed at three academic interventional spine practices. METHODS: Quality assurance databases at three academic interventional pain management practices that utilize evidence-based guidelines [1] were interrogated for immediate complications from interventional pain procedures. Review of the electronic medical record verified or refuted the occurrence of a complication. Same-day emergency department transfers or visits were also identified by a records search. RESULTS: Immediate complication data were available for 26,061 consecutive procedures. A radiology practice performed 19,170 epidural steroid (primarily transforaminal), facet, sacroiliac, and trigger point injections (2006-2013). A physiatry practice performed 6,190 spine interventions (2004-2009). A second physiatry practice performed 701 spine procedures (2009-2010). There were no major complications (permanent neurologic deficit or clinically significant bleeding [e.g., epidural hematoma]) with any procedure. Overall complication rate was 1.9% (493/26,061). Vasovagal reactions were the most frequent event (1.1%). Nineteen patients (<0.1%) were transferred to emergency departments for: allergic reactions, chest pain, symptomatic hypertension, and a vasovagal reaction. CONCLUSION: This study demonstrates that interventional pain procedures are safely performed with extremely low immediate adverse event rates when evidence-based guidelines are observed.

Imaging Determinants of Clinical Effectiveness of Lumbar Transforaminal Epidural Steroid Injections.

OBJECTIVE: To examine associations between imaging characteristics of compressive lesions and patient outcomes after lumbar transforaminal epidural steroid injections (TFESIs) stratified by steroid formulation (solution versus suspension). DESIGN/SUBJECTS: Retrospective observational study, academic radiology practice. A 516-patient sample was selected from 2,634 consecutive patients receiving lumbar TFESI for radicular pain. METHODS: The advanced imaging study(s) preceding sampled TFESI were reviewed. Compressive lesions were described by a) nature of the lesion [disc herniation, fixed stenosis, synovial cyst, epidural fibrosis, no lesion] b) degree of neural compression [4 part scale], and c) presence of a tandem lesion. Associations between 2-month categorical outcomes (responder rates for pain, functional recovery) and imaging characteristics, stratified by steroid formulation, were examined with chi-squared tests of categorical outcomes and multivariable logistic regression models. RESULTS: Disc herniation patients had more responders for functional recovery than patients with fixed lesions (54% versus 38%, P = 0.01). Patients with fixed lesions receiving steroid solution (dexamethasone) had more responders for pain relief, with a similar trend for functional recovery, than patients receiving suspensions (59% versus 40%, P = 0.01). Outcomes for patients with fixed lesions treated with dexamethasone were not statistically different from those for disc herniation patients. Patients with single compressive lesions had more responders than those with tandem lesions (55% versus 41%, P = 0.03). CONCLUSION: In the entire sample, outcomes for disc herniations were more favorable than for fixed lesions. However, fixed lesions treated with dexamethasone had outcomes indistinguishable from disc herniations. Single lesions had better outcomes than tandem lesions.

Adverse Event Rates Associated with Transforaminal and Interlaminar Epidural Steroid Injections: A Multi-Institutional Study.

BACKGROUND: Transforaminal epidural steroid injections (TFESI) have demonstrated efficacy and effectiveness in treatment of radicular pain. Despite little evidence of efficacy/effectiveness, interlaminar epidural steroid injections (ILESI) are advocated by some as primary therapy for radicular pain due to purported greater safety. OBJECTIVE: To assess immediate and delayed adverse event rates of TFESI and ILESI injections at three academic medical centers utilizing International Spine Intervention Society practice guidelines. METHODS: Quality assurance databases from a Radiology and two physical medicine and rehabilitation (PM&R) practices were interrogated. Medical records were reviewed, verifying immediate and delayed adverse events. RESULTS: There were no immediate major adverse events of neurologic injury or hemorrhage in 16,638 consecutive procedures in all spine segments (14,956 TFESI; 1,682 ILESI). Vasovagal reactions occurred in 1.2% of procedures, more frequently (P = 0.004) in TFESI (1.3%) than ILESI (0.5%). Dural punctures occurred in 0.06% of procedures, more commonly after ILESI (0.2% vs 0.04%, P = 0.006). Delayed follow up on PM&R patients (92.5% and 78.5, next business day) and radiology patients (63.1%, 2 weeks) identified no major adverse events of neurologic injury, hemorrhage, or infection. There were no significant differences in delayed minor adverse event rates. Central steroid response (sleeplessness, flushing, nonpositional headache) was seen in 2.6% of both TFESI and ILESI patients. 2.1% of TFESI and 1.8% of ILESI patients reported increased pain. No long-term sequelae were seen from any immediate or delayed minor adverse event. CONCLUSIONS: Both transforaminal and ILESI are safely performed with low immediate and delayed adverse event rates when informed by evidence-based procedural guidelines. By demonstrating comparable safety, this study suggests that the choice between ILESI and TFESIs can be based on documented efficacy and effectiveness and not driven by safety concerns.

The effectiveness of repeat lumbar transforaminal epidural steroid injections.

OBJECTIVE: The aim of this study was to determine 1) if repeat lumbar transforaminal epidural steroid injections (TFESIs) resulted in recovery of pain relief, which has waned since an index injection, and 2) if cumulative benefit could be achieved by repeat injections within 3 months of the index injection. DESIGN: Retrospective observational study with statistical modeling of the response to repeat TFESI. SETTING: Academic radiology practice. PATIENTS: Two thousand eighty-seven single-level TFESIs were performed for radicular pain on 933 subjects. Subjects received repeat TFESIs >2 weeks and <1 year from the index injection. METHODS: Hierarchical linear modeling was performed to evaluate changes in continuous and categorical pain relief outcomes after repeat TFESI. Subgroup analyses were performed on patients with <3 months duration of pain (acute pain), patients receiving repeat injections within 3 months (clustered injections), and in patients with both acute pain and clustered injections. RESULTS: Repeat TFESIs achieved pain relief in both continuous and categorical outcomes. Relative to the index injection, there was a minimal but statistically significant decrease in pain relief in modeled continuous outcome measures with subsequent injections. Acute pain patients recovered all prior benefit with a statistically significant cumulative benefit. Patients receiving clustered injections achieved statistically significant cumulative benefit, of greater magnitude in acute pain patients. CONCLUSION: Repeat TFESI may be performed for recurrence of radicular pain with the expectation of recovery of most or all previously achieved benefit; acute pain patients will likely recover all prior benefit. Repeat TFESIs within 3 months of the index injection can provide cumulative benefit.

A practice audit of CT-guided injections of pars interarticularis defects in patients with axial low back pain: a primer for further investigation.

OBJECTIVE: To assess whether computed tomography (CT)-guided injections of local anesthetic and corticosteroid into chronic lumbar pars interarticularis defects may identify and provide benefit to a cohort of patients where the pars defects act as a primary axial pain generator. DESIGN: Retrospective practice audit. SETTING: Single academic radiology pain management practice. PATIENTS: 59 consecutive patients undergoing CT-guided injections of lumbar pars defects. METHODS: Patients were assessed with a pain numerical rating scale (NRS, 0-10) and Roland-Morris disability questionnaire (R-M) prior to injection and at 2 weeks and 2 months follow-up. For categorical outcomes, successful pain relief response was defined as either ≥50% reduction in NRS or pain 0/10; functional response was defined as ≥40% reduction in R-M score. Continuous outcomes (mean NRS, R-M scores) were assessed for significant change following injection. RESULTS: For categorical outcomes, 37.9% of patients were responders at 2 months' follow-up; 20.7 % had complete relief of index pain. For functional recovery, 34.5% were responders at 2 months. Using continuous outcomes, mean NRS was 5.4 ± 2.1 prior to injection and 3.6 ± 2.6 at 2 months (P < 0.0001). Mean R-M score was 11.7 ± 6.0 prior to injection and 9.0 ± 5.4 at 2 months (P = 0.001). There were no complications. CONCLUSIONS: This practice audit suggests that in patients with axial low back pain and chronic pars defects, the pars defects may be implicated as the primary axial pain generator in a small subgroup of patients. Local deposition of corticosteroids into the pars defect may provide significant pain relief in one out of three patients, and complete relief in one out of five patients. This data suggest there may be benefit to pursuing randomized controlled trials of pars injections comparing steroid injection with placebo.

CT-guided cervical transforaminal epidural steroid injections: technical insights.

Recent studies have described the safety and efficacy of computed tomography (CT)-guided cervical transforaminal epidural steroid injections with both the anterolateral and posterior approach. Although fluoroscopy is the most common form of image guidance for these procedures, CT guidance offers many advantages. However, some key features of CT guidance in these procedures need to be considered to ensure safe and technically successful outcomes.

A review of epidural and non-epidural contrast flow patterns during fluoroscopic and CT-guided epidural steroid injections.

Epidural steroid injections are commonly performed using fluoroscopic or CT guidance. With both modalities, the injection of contrast material is necessary before steroid administration to ensure adequate epidural flow and exclude non-epidural flow. While fluoroscopic guidance is conventional, CT is utilized at some centers and can be particularly helpful in the setting of challenging or postoperative anatomy. It is important for proceduralists to be adept at evaluating contrast media flow patterns under both modalities. The goal of this review article is to describe and provide examples of epidural and non-epidural flow patterns on both conventional fluoroscopy and CT. Specific non-epidural patterns discussed include intrathecal flow, intradural/subdural flow, vascular uptake, flow into the retrodural space of Okada, inadvertent facet joint flow, and intradiscal flow.

Use of corticosteroids for adult chronic pain interventions: sympathetic and peripheral nerve blocks, trigger point injections - guidelines from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, the American Society of Interventional Pain Physicians, the International Pain and Spine Intervention Society, and the North American Spine Society.

BACKGROUND: There is potential for adverse events from corticosteroid injections, including increase in blood glucose, decrease in bone mineral density and suppression of the hypothalamic-pituitary axis. Published studies note that doses lower than those commonly injected provide similar benefit. METHODS: Development of the practice guideline was approved by the Board of Directors of American Society of Regional Anesthesia and Pain Medicine with several other societies agreeing to participate. The scope of guidelines was agreed on to include safety of the injection technique (landmark-guided, ultrasound or radiology-aided injections); effect of the addition of the corticosteroid on the efficacy of the injectate (local anesthetic or saline); and adverse events related to the injection. Based on preliminary discussions, it was decided to structure the topics into three separate guidelines as follows: (1) sympathetic, peripheral nerve blocks and trigger point injections; (2) joints; and (3) neuraxial, facet, sacroiliac joints and related topics (vaccine and anticoagulants). Experts were assigned topics to perform a comprehensive review of the literature and to draft statements and recommendations, which were refined and voted for consensus (≥75% agreement) using a modified Delphi process. The United States Preventive Services Task Force grading of evidence and strength of recommendation was followed. RESULTS: This guideline deals with the use and safety of corticosteroid injections for sympathetic, peripheral nerve blocks and trigger point injections for adult chronic pain conditions. All the statements and recommendations were approved by all participants after four rounds of discussion. The Practice Guidelines Committees and Board of Directors of the participating societies also approved all the statements and recommendations. The safety of some procedures, including stellate blocks, lower extremity peripheral nerve blocks and some sites of trigger point injections, is improved by imaging guidance. The addition of non-particulate corticosteroid to the local anesthetic is beneficial in cluster headaches but not in other types of headaches. Corticosteroid may provide additional benefit in transverse abdominal plane blocks and ilioinguinal/iliohypogastric nerve blocks in postherniorrhaphy pain but there is no evidence for pudendal nerve blocks. There is minimal benefit for the use of corticosteroids in trigger point injections. CONCLUSIONS: In this practice guideline, we provided recommendations on the use of corticosteroids in sympathetic blocks, peripheral nerve blocks, and trigger point injections to assist clinicians in making informed decisions.