Neuromodulation for chronic pain.

Neuromodulation is an expanding area of pain medicine that incorporates an array of non-invasive, minimally invasive, and surgical electrical therapies. In this Series paper, we focus on spinal cord stimulation (SCS) therapies discussed within the framework of other invasive, minimally invasive, and non-invasive neuromodulation therapies. These therapies include deep brain and motor cortex stimulation, peripheral nerve stimulation, and the non-invasive treatments of repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous electrical nerve stimulation. SCS methods with electrical variables that differ from traditional SCS have been approved. Although methods devoid of paraesthesias (eg, high frequency) should theoretically allow for placebo-controlled trials, few have been done. There is low-to-moderate quality evidence that SCS is superior to reoperation or conventional medical management for failed back surgery syndrome, and conflicting evidence as to the superiority of traditional SCS over sham stimulation or between different SCS modalities. Peripheral nerve stimulation technologies have also undergone rapid development and become less invasive, including many that are placed percutaneously. There is low-to-moderate quality evidence that peripheral nerve stimulation is effective for neuropathic pain in an extremity, low quality evidence that it is effective for back pain with or without leg pain, and conflicting evidence that it can prevent migraines. In the USA and many areas in Europe, deep brain and motor cortex stimulation are not approved for chronic pain, but are used off-label for refractory cases. Overall, there is mixed evidence supporting brain stimulation, with most sham-controlled trials yielding negative findings. Regarding non-invasive modalities, there is moderate quality evidence that repetitive transcranial magnetic stimulation does not provide meaningful benefit for chronic pain in general, but conflicting evidence regarding pain relief for neuropathic pain and headaches. For transcranial direct current stimulation, there is low-quality evidence supporting its benefit for chronic pain, but conflicting evidence regarding a small treatment effect for neuropathic pain and headaches. For transcutaneous electrical nerve stimulation, there is low-quality evidence that it is superior to sham or no treatment for neuropathic pain, but conflicting evidence for non-neuropathic pain. Future research should focus on better evaluating the short-term and long-term effectiveness of all neuromodulation modalities and whether they decrease health-care use, and on refining selection criteria and treatment variables.

Potential Cost Savings with 60-day Peripheral Nerve Stimulation Treatment in Chronic Axial Low Back Pain.

INTRODUCTION: Chronic axial low back pain (CLBP) that is not responsive to medication management or physical therapy often requires significant clinical intervention. Several interventional pain management options exist, including a 60-day peripheral nerve stimulation (PNS) treatment. This economic evaluation investigated the potential for projected cost savings associated with prioritizing 60-day PNS treatment relative to a 'standard of care' (SOC) approach (where patients do not have access to 60-day PNS). METHODS: A decision tree (supervised machine learning) model tracked treatment progression across two hypothetical cohorts of US patients with CLBP in whom non-interventional options were ineffective (Cohort A: treatment starting with 60-day PNS followed by any additional interventional and surgical treatments versus Cohort B: standard of care interventional and surgical treatments without access to 60-day PNS). Treatment efficacy estimates were based on published success rates. Conditional on treatment failure, up to two additional interventions were considered within the 12-month time frame in both cohorts. SOC treatment options included epidural injection, radiofrequency ablation (RFA), basivertebral nerve ablation (BVNA), PNS permanent implant (PNS-PI), spinal cord stimulator (SCS) trial/implant, and spinal fusion surgery. Treatment choice probabilities in both cohort algorithms were based on clinician interviews. Costs were based on national Medicare reimbursement levels in the ambulatory surgery center (ASC) setting. Savings reflected the difference in projected costs between cohorts. A Monte Carlo simulation and sensitivity analyses were conducted to generate confidence intervals and identify important inputs. RESULTS: The treatment algorithm which prioritized initial 60-day PNS treatment was projected to save $8056 (95% CI $6112-$9981) per patient during the first year of interventional treatment relative to the SOC approach. CONCLUSIONS: Use of the 60-day PNS treatment as an initial interventional treatment in patients with CLBP may result in significant savings for Medicare. Projected savings may be even larger for commercial payers covering non-Medicare patients.

A Retrospective Review of Real-world Outcomes Following 60-day Peripheral Nerve Stimulation for the Treatment of Chronic Pain.

BACKGROUND: Real-world data can provide important insights into treatment effectiveness in routine clinical practice. Studies have demonstrated that in multiple different pain indications temporary (60-day) percutaneous peripheral nerve stimulation (PNS) treatment can produce significant relief, but few real-world studies have been published. The present study is the first real-world, retrospective review of a large database depicting outcomes at the end of a 60-day PNS treatment period. OBJECTIVES: Evaluate outcomes during a 60-day PNS treatment in routine clinical practice. STUDY DESIGN: Secondary retrospective review. METHODS: Anonymized records of 6,160 patients who were implanted with a SPRINT PNS System from August 2019 through August 2022 were retrospectively reviewed from a national real-world database. The percentage of patients with ? 50% pain relief and/or improvement in quality of life was evaluated and stratified by nerve target. Additional outcomes included average and worst pain score, patient-reported percentage of pain relief, and patient global impression of change. RESULTS: Overall, 71% of patients (4,348/6,160) were responders with >= 50% pain relief and/or improvement in quality of life; pain relief among responders averaged 63%. The responder rate was largely consistent across nerve targets throughout the back and trunk, upper and lower extremities, and posterior head and neck. LIMITATIONS: This study was limited by its retrospective nature and reliance on a device manufacturer's database. Additionally, detailed demographic information and measures for pain medication usage and physical function were not assessed. CONCLUSIONS: This retrospective analysis supports recent prospective studies demonstrating that 60-day percutaneous PNS can provide significant relief across a wide range of nerve targets. These data serve an important role in complementing the findings of published prospective clinical trials.

Subcutaneous peripheral nerve stimulation with inter-lead stimulation for axial neck and low back pain: case series and review of the literature.

OBJECTIVES: While pain in the extremities often responds to treatment using spinal cord stimulation (SCS), axial pain is notoriously refractory to SCS. Interest in subcutaneous peripheral nerve stimulation (SQ PNS) as an alternative to SCS has emerged, but the most appropriate electrode locations and neurostimulator programming techniques are not yet clear. METHODS: A retrospective review was conducted of consecutive patients evaluated from August 2009 to December 2010 who had undergone trial of SQ PNS with inter-lead stimulation for axial spine pain. Patients proceeding to implant were followed postoperatively with routine clinical visits and a survey form at last follow-up. Ultrasound was used intraoperatively to ensure placement of electrodes at the appropriate depth in patients with larger body mass index. Primary outcome was patient-reported pain relief at last follow-up. Literature review was conducted by searching MEDLINE (1948-present) and through an unstructured review by the authors. RESULTS: Ten patients underwent trial of SQ PNS and six proceeded to permanent implantation. Fifty percent (3/6) of implanted patients preferred neurostimulation programming that included inter-lead stimulation ("cross-talk"). Average duration of postoperative follow-up was 4.5 months (range 2-9 months). Average patient-reported pain relief at last follow-up was 45% (range 20-80%). One patient required re-operation for migration. Patients not proceeding to implant had paresthesia coverage but no analgesia. CONCLUSION: SQ PNS is a promising therapy for axial neck and back pain based on a small cohort of patients. Ultrasound was useful to assist with electrode placement at the most appropriate depth beneath the skin. While inter-lead stimulation has been preferred by patients in published reports, we did not find it clearly influenced pain relief. Future investigations should include a randomized, controlled study design, as well as defined implantation technique and neurostimulator programming algorithms.

Preoperative gabapentin for acute post-thoracotomy analgesia: a randomized, double-blinded, active placebo-controlled study.

BACKGROUND: The role of preoperative gabapentin in postoperative pain management is not clear, particularly in patients receiving regional blockade. Patients undergoing thoracotomy benefit from epidural analgesia but still may experience significant postoperative pain. We examined the effect of preoperative gabapentin in thoracotomy patients. METHODS: Adults undergoing elective thoracotomy were enrolled in this prospective, randomized, double-blinded, placebo-controlled study, and randomly assigned to receive 600 mg gabapentin or active placebo (12.5 mg diphenhydramine) orally within 2 hours preoperatively. Standardized management included thoracic epidural infusion, intravenous patient-controlled opioid analgesia, acetaminophen and ketorolac. Pain scores, opioid use and side effects were recorded for 48 hours. Pain was also assessed at 3 months. RESULTS: One hundred twenty patients (63 placebo and 57 gabapentin) were studied. Pain scores did not significantly differ at any time point (P = 0.53). Parenteral and oral opioid consumption was not significantly different between groups on postoperative day 1 or 2 (P > 0.05 in both cases). The frequency of side effects such as nausea and vomiting or respiratory depression was not significantly different between groups, but gabapentin was associated with decreased frequency of pruritus requiring nalbuphine (14% gabapentin vs. 43% control group, P < 0.001). The frequency of patients experiencing pain at 3 months post-thoracotomy was also comparable between groups (70% gabapentin vs. 66% placebo group, P = 0.72). CONCLUSIONS: A single preoperative oral dose of gabapentin (600 mg) did not reduce pain scores or opioid consumption following elective thoracotomy, and did not confer any analgesic benefit in the setting of effective multimodal analgesia that included thoracic epidural infusion.

Peripherally Induced Reconditioning of the Central Nervous System: A Proposed Mechanistic Theory for Sustained Relief of Chronic Pain with Percutaneous Peripheral Nerve Stimulation.

Peripheral nerve stimulation (PNS) is an effective tool for the treatment of chronic pain, although its efficacy and utilization have previously been significantly limited by technology. In recent years, purpose-built percutaneous PNS devices have been developed to overcome the limitations of conventional permanently implanted neurostimulation devices. Recent clinical evidence suggests clinically significant and sustained reductions in pain can persist well beyond the PNS treatment period, outcomes that have not previously been observed with conventional permanently implanted neurostimulation devices. This narrative review summarizes mechanistic processes that contribute to chronic pain, and the potential mechanisms by which selective large diameter afferent fiber activation may reverse these changes to induce a prolonged reduction in pain. The interplay of these mechanisms, supported by data in chronic pain states that have been effectively treated with percutaneous PNS, will also be discussed in support of a new theory of pain management in neuromodulation: Peripherally Induced Reconditioning of the Central Nervous System (CNS).

The vertebral artery is unlikely to be the sole source of vascular complications occurring during stellate ganglion block.

INTRODUCTION: Stellate ganglion block (SGB) is commonly performed for upper extremity complex regional pain syndrome and other conditions. Known complications of stellate block include Horner's syndrome, hoarseness, hematoma formation, airway compromise, immediate seizure (presumably from vertebral artery injection), and death. A previous arterial anatomy study demonstrated other vessels, eg, the ascending and deep cervical arteries, reinforcing the blood supply of the spinal cord and brain stem. The potential role of these vessels in the pathogenesis of seizures or hematoma during SGB has not been studied. METHODS: The anatomical recording log from 10 cadaver dissections and photographic records of same were reviewed to ascertain the presence of the ascending or deep cervical arteries, or other branches emanating from the thyrocervical or costocervical trunk and their relationship to the medial anterior surface of the C6 and C7 transverse processes. RESULTS: In 4 cases, as determined by the dissection log, and in 6 cases, determined by photographic images, the ascending cervical artery or a branch from the thyrocervical trunk passed over the anterior aspect of the transverse processes of C6 or C7. DISCUSSION: Arterial vessels other than the vertebral artery that also supply the anterior spinal cord and brain stem pass directly anterior to the transverse processes at the most common sites of the SGB. It is anatomically possible, therefore, that accidental injection or induced spasm of these vessels and not the vertebral arteries is responsible for some cases of seizure, hematoma, or other vascular complications during SGB.

Ultrasound-guided permanent implantation of peripheral nerve stimulation (PNS) system for neuropathic pain of the extremities: original cases and outcomes.

OBJECTIVE: Our objective is to describe our experience applying a minimally invasive, ultrasound-assisted technique for peripheral nerve stimulation (PNS) trial and permanent implantation in patients with neuropathic extremity pain. DESIGN: Retrospective case series and review of the literature. Setting. Tertiary referral center and academic medical center. PATIENTS: Patients with upper or lower extremity neuropathic pain resistant to other therapies who responded to an ultrasound-guided peripheral nerve block at a proximal location. Interventions. Ultrasound-assisted through-the-needle placement of percutaneous neurostimulation electrodes on target major peripheral nerves for fully percutaneous trial, staged trial or permanent implantation of PNS system. A PNS trial period of 3-7 days was used. OUTCOME MEASURES: Pain relief at last follow-up, complications, therapeutic limitations due to technique as applied. Results. Six of eight (75%) patients and 7/9 (78%) peripheral nerves had a successful trial and underwent permanent PNS system implantation using a minimally invasive, ultrasound-assisted technique from November 2007 to December 2008. All but one patient with an implanted PNS system had > or =50% pain relief at last follow-up and 3/7 (43%) permanent systems were associated with > or =80% relief. Loss of paresthesia required revision to dual-lead systems in upper extremity radial nerve PNS. Infection led to explant in one case. CONCLUSIONS: In a small series of patients, a minimally invasive, ultrasound-assisted technique for PNS trial, and permanent PNS implantation proved feasible. Patients without adequate analgesia during neurostimulation trial avoided surgical incision and those undergoing permanent implantation were not subjected to the potential morbidity associated with nerve dissection.

Impact of perioperative pain management on cancer recurrence: an ASRA/ESRA special article.

Cancer causes considerable suffering and 80% of advanced cancer patients experience moderate to severe pain. Surgical tumor excision remains a cornerstone of primary cancer treatment, but is also recognized as one of the greatest risk factors for metastatic spread. The perioperative period, characterized by the surgical stress response, pharmacologic-induced angiogenesis, and immunomodulation results in a physiologic environment that supports tumor spread and distant reimplantation.In the perioperative period, anesthesiologists may have a brief and uniquewindow of opportunity to modulate the unwanted consequences of the stressresponse on the immune system and minimize residual disease. This reviewdiscusses the current research on analgesic therapies and their impact ondisease progression, followed by an evidence-based evaluation of perioperativepain interventions and medications.

Thoracic spinal cord stimulation for post-ablation cardiac pain in a patient with permanent pacemaker.

BACKGROUND: Spinal cord stimulation (SCS) is increasingly utilized for inoperable, intractable chest pain because of ischemia. Because patients with ischemic heart disease commonly have permanent cardiac pacemakers (PPM) or automated implantable cardio-defibrillators (AICD), concurrent use of SCS and PPM or AICD may grow. Interference between SCS and PPM or AICD devices is potentially dangerous and has been previously reported. CASE REPORT: A 51-year-old woman who underwent multiple catheter-based cardiac ablations for a variety of tachy-atrial arrhythmias. These procedures included atrioventricular node destruction, which left her PPM-dependent (third degree heart block with an intrinsic heart rate in the 30s). During the course of her cardiac treatment, she developed chest pain which was not amenable to cardiac intervention and was refractory to medical management. The patient was evaluated for consideration of SCS and ultimately underwent implantation. Procedures evaluating SCS-PPM compatibility were followed and are described. Immediately after SCS implantation and at 6 months follow-up, the patient experienced improved pain relief. DISCUSSION: Others have reported SCS implantation in patients with PPM. This is the first report to describe safe and effective use of an Advanced Bionics SCS in a patient with a Guidant PPM. In addition, we speculate that this patient's cardiac pain may have been other than ischemic in origin. As such, this case may represent a unique clinical scenario. Despite many cases series and case reports demonstrating safety of concurrent SCS and PPM or AICD, the complexity of these technologies requires continued demonstration of device compatibility in novel contexts.

Interventional Spine and Pain Procedures in Patients on Antiplatelet and Anticoagulant Medications (Second Edition): Guidelines From the American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, the American Academy of Pain Medicine, the International Neuromodulation Society, the North American Neuromodulation Society, and the World Institute of Pain.

The American Society of Regional Anesthesia and Pain Medicine (ASRA) 2012 survey of meeting attendees showed that existing ASRA anticoagulation guidelines for regional anesthesia were insufficient for their needs. Those surveyed agreed that procedure-specific and patient-specific factors required separate guidelines for pain and spine procedures. In response, a guidelines committee was formed. After preliminary review of published complications reports and studies, the committee stratified interventional spine and pain procedures according to potential bleeding risk: low-, intermediate-, and high-risk procedures. The ASRA regional anesthesia anticoagulation guidelines were largely deemed appropriate for the low- and intermediate-risk categories, but the high-risk category required further investigation. The first guidelines specific to interventional spine and pain procedures were published in 2015. Recent reviews evaluating bleeding complications in patients undergoing specific interventional pain procedures, the development of new regional anesthesia and acute pain guidelines, and the development of new anticoagulants and antiplatelet medications necessitate complementary updated guidelines. The authors desired coordination with the authors of the recently updated regional and acute pain anticoagulation guidelines. The latest evidence was sought through extensive database search strategies and the recommendations were evidence based when available and pharmacology driven otherwise. We could not provide strength and grading of these recommendations because there are not enough well-designed large studies concerning interventional pain procedures to support such grading. Although the guidelines could not always be based on randomized studies or on large numbers of patients from pooled databases, it is hoped that they will provide sound recommendations and the evidentiary basis for such recommendations. This publication is intended as a living document to be updated periodically with consideration of new evidence.

Intracranial hypotension following motor vehicle accident: an overlooked cause of post-traumatic head and neck pain?

Motor vehicle accidents result in many patients with chronic head and neck pain, some of which meet the criteria for a "whiplash syndrome." The cervical zygapophysial joint synovium, muscular, and ligamentous strains and other anatomical sites are often implicated in the pathophysiology of these cases. Some patients have a characteristic constellation of vague neurological symptoms, often including headache, posterior neck discomfort, dizziness, nausea, and sometimes visual changes. Recently presented research has noted that some patients who have a whiplash-associated disorder have imaging findings consistent with a low-pressure cerebrospinal fluid leak. Some of these patients respond favorably to high-volume epidural blood patch. The following case presentation focuses on the differential diagnosis of a post-traumatic headache syndrome, specific imaging findings, and treatment strategies.

The Development and Validation of a Quality Assessment and Rating of Technique for Injections of the Spine (AQUARIUS).

BACKGROUND AND OBJECTIVES: Systematic reviews evaluate the utility of procedural interventions of the spine, including epidural steroid injections (ESIs). However, existing quality assessment tools either fail to account for proper technical quality and patient selection or are not validated. We developed and validated a simple scale for ESIs to provide a quality assessment and rating of technique for injections of the spine (AQUARIUS). METHODS: Seven experts generated items iteratively based on prior ESI technique studies and professional judgment. Following testing for face and content validity, a 17-item instrument was used by 8 raters from 2 different backgrounds to assess 12 randomized controlled trials, selected from 3 different categories. Using frequency of assessment, a 12-item instrument was also generated. Both instruments underwent reliability (intraclass correlation coefficient), validity (ability to distinguish "low," "random," and "high" study categories), and diagnostic accuracy (receiver operating characteristics) testing. RESULTS: Both 17- and 12-item instruments were scored consistently by raters regardless of background, with overall intraclass correlation coefficients of 0.72 (95% confidence interval [CI], 0.53-0.89) and 0.71 (95% CI, 0.51-0.89), respectively. Both instruments discriminated between clinical trials from all 3 categories. Diagnostic accuracy was similar for the 2 instruments, with areas under receiver operating characteristic curves of 0.89 (95% CI, 0.82-0.96) and 0.90 (95% CI, 0.82-0.97), respectively. CONCLUSIONS: The instrument in both 17- and 12-item formats demonstrates good reliability and diagnostic accuracy in rating ESI studies. As a complement to other tools that assess bias, the instrument may improve the ability to evaluate evidence for systematic reviews and improve clinical trial design.

Real-Time Detection of Periforaminal Vessels in the Cervical Spine: An Ultrasound Survey.

BACKGROUND AND OBJECTIVES: Compared with the thoracic and lumbar spine, transforaminal epidural injections and medial branch blocks in the cervical spine are associated with a higher incidence of neurological complications. Accidental breach of small periforaminal arteries has been implicated in many instances. In this observational study, using ultrasonography, we surveyed the incidence of periforaminal bloods vessels in the cervical spine. METHODS: Patients undergoing ultrasound-guided cervical medial branch blocks were scanned using color power and pulsed wave Doppler. Five levels from C2/C3 to C6/C7 were studied. Incidental blood vessels located between the anterior tubercles of the transverses process and the posterior borders of the articular pillars were included for analysis. We recorded the diameter and position of arteries relative to contiguous bony landmarks as well the number of veins. RESULTS: In 102 patients, we performed a total 201 scans (1005 cervical levels). Of the 363 incidental vessels identified, 238 were arteries (mean diameter, 1.25 ± 0.45 mm). The latter were most commonly found at the posterior foraminal aspects of C5, C6, and C7 (13%, 11%, and 16% of scans, respectively); the transverse processes of C5 and C6 (10% and 16% of scans, respectively); and the articular pillars of C6 and C7 (19% and 16% of scans, respectively). CONCLUSIONS: Small periforaminal arteries are prevalent along the lateral aspect of the cervical spine, adjacent to areas commonly targeted by nerve block procedures. Further trials are required to determine if ultrasound guidance can reduce the incidence of complications related to accidental vascular breach.

Anatomy of the cervical intervertebral foramina: vulnerable arteries and ischemic neurologic injuries after transforaminal epidural injections.

Cervical transforaminal epidural steroid injections are performed for the treatment of radicular pain. Multiple recent case reports have raised safety concerns regarding neurologic deficits such as anterior spinal artery syndrome and cerebellar injury after these injections. To investigate the potential causes of these injuries, an anatomic study was conducted. In this study of 10 embalmed cadavers, the cervical intervertebral foramina were examined to determine if the ascending or deep cervical arteries supplied radicular or segmental medullary arteries potentially susceptible to cannulation or needle trauma during transforaminal injection. In two specimens, dissection was carried down to the spinal cord, demonstrating the anterior spinal, radicular, and segmental medullary arteries. Of 95 intervertebral foramina dissected, 21 had an arterial vessel proximal to the posterior aspect of the foraminal opening. Seven of these 21 were spinal branches that entered the foramen posteriorly, potentially forming radicular or segmental medullary vessels to the spinal cord. One additional ascending cervical artery formed a segmental medullary artery that joined the anterior spinal artery. This would only be injured by anterior needle misplacement. Of the seven foraminal branches, three were included in the deep dissections. Two contributed to segmental medullary arteries and one to a radicular artery. Variable anastomoses between the vertebral and cervical arteries were found. Therefore, it is possible to introduce steroid particles into the vertebral circulation via the cervical arteries. Critical arteries are located in the posterior aspect of the intervertebral foramen and may be vulnerable to injection or injury during transforaminal epidural steroid injection.

Neurologic Evaluation and Management of Perioperative Nerve Injury.

Neurologic injury after regional anesthesia or pain medicine procedures is rare. Postprocedural neurologic deficits may create high levels of anxiety for the patient and practitioner, although most deficits are limited in severity and can be expected to fully resolve with time. Postoperative anesthesia-related neuraxial and peripheral nerve injuries are reviewed to define an efficient, structured approach to these complications. Emphasis is placed on acutely stratifying the urgency and scope of diagnostic testing or consultation necessity, initiating appropriate definitive treatments, and defining appropriate out-of-hospital follow-up and symptom management. WHAT'S NEW: Studies pertinent to the recognition, evaluation, and treatment of neurologic assessment of perioperative nerve injury and published since the last advisory on the topic are reviewed and a new structured algorithmic approach is proposed. The evolving literature on postoperative inflammatory neuropathies is reviewed to help define the clinical criteria and to identify patients who would benefit from early neurological evaluation. New sections review potential acute interventions to improve neurologic outcome and long-term management of neuropathic pain resulting from perioperative nerve injury.

Interventional spine and pain procedures in patients on antiplatelet and anticoagulant medications: guidelines from the American Society of Regional Anesthesia and Pain Medicine, the European Society of Regional Anaesthesia and Pain Therapy, the American Academy of Pain Medicine, the International Neuromodulation Society, the North American Neuromodulation Society, and the World Institute of Pain.

Interventional spine and pain procedures cover a far broader spectrum than those for regional anesthesia, reflecting diverse targets and goals. When surveyed, interventional pain and spine physicians attending the American Society of Regional Anesthesia and Pain Medicine (ASRA) 11th Annual Pain Medicine Meeting exhorted that existing ASRA guidelines for regional anesthesia in patients on antiplatelet and anticoagulant medications were insufficient for their needs. Those surveyed agreed that procedure-specific and patient-specific factors necessitated separate guidelines for pain and spine procedures. In response, ASRA formed a guidelines committee. After preliminary review of published complication reports and studies, committee members stratified interventional spine and pain procedures according to potential bleeding risk as low-, intermediate-, and high-risk procedures. The ASRA guidelines were deemed largely appropriate for the low- and intermediate-risk categories, but it was agreed that the high-risk targets required an intensive look at issues specific to patient safety and optimal outcomes in pain medicine. The latest evidence was sought through extensive database search strategies and the recommendations were evidence-based when available and pharmacology-driven otherwise. We could not provide strength and grading of these recommendations as there are not enough well-designed large studies concerning interventional pain procedures to support such grading. Although the guidelines could not always be based on randomized studies or on large numbers of patients from pooled databases, it is hoped that they will provide sound recommendations and the evidentiary basis for such recommendations.

The Second ASRA Practice Advisory on Neurologic Complications Associated With Regional Anesthesia and Pain Medicine: Executive Summary 2015.

Neurologic injury associated with regional anesthetic or pain medicine procedures is extremely rare. The Second American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Neurologic Complications Associated With Regional Anesthesia and Pain Medicine focuses on those complications associated with mechanical, ischemic, or neurotoxic injury of the neuraxis or peripheral nervous system. As with the first advisory, this iteration does not focus on hemorrhagic or infectious complications or local anesthetic systemic toxicity, all of which are the subjects of separate practice advisories. The current advisory offers recommendations to aid in the understanding and potential limitation of rare neurologic complications that may arise during the practice of regional anesthesia and/or interventional pain medicine. WHAT'S NEW: The Second American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Neurologic Complications Associated With Regional Anesthesia and Pain Medicine updates information that was originally presented at the Society's first open forum on this subject (2005) and published in 2008. Portions of the second advisory were presented in an open forum (2012) and are herein updated, with attention to those topics subject to evolving knowledge since the first and second advisory conferences. The second advisory briefly summarizes recommendations that have not changed substantially. New to this iteration of the advisory is information related to the risk of nerve injury inherent to common orthopedic surgical procedures. Recommendations are expanded regarding the preventive role of various monitoring technologies such as ultrasound guidance and injection pressure monitoring. New clinical recommendations focus on emerging concerns including spinal stenosis and vertebral canal pathologies, blood pressure management during neuraxial anesthesia, administering blocks in anesthetized or deeply sedated patients, patients with preexisting neurologic disease, and inflammatory neuropathies. An updated diagnostic and treatment algorithm is presented.

Epidural abscess and meningitis after epidural corticosteroid injection.

Epidural abscess with and without associated meningitis after epidural corticosteroid injections for radicular back pain is a rarely reported complication. We report the occurrence of an epidural abscess and meningitis in a 70-year-old man after 2 epidural corticosteroid injections for treatment of acute radicular lumbar back pain. At the time of diagnosis, cerebrospinal fluid cultures grew Staphylococcus aureus, and the patient was treated with intravenous antibiotics. Possible predisposing factors for the development of an epidural abscess and meningitis in this patient include a 2-year history of neutropenia and an accidental dural puncture that occurred during performance of the first epidural injection. A literature search identified 11 reported cases of epidural abscess, 2 of epidural abscess and meningitis, and 1 of meningitis attributed to epidural corticosteroid injections. Eight of the 14 reported patients were immunocompromised, and 8 (67%) of the 12 in whom cultures of blood, cerebrospinal fluid, or epidural pus were performed had results positive for S. aureus. Antibiotic prophylaxis for S. aureus should be considered for immunocompromised patients undergoing epidural corticosteroid injections.