The Polyanalgesic Consensus Conference (PACC)®: Intrathecal Drug Delivery Guidance on Safety and Therapy Optimization When Treating Chronic Noncancer Pain.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians and scientists based on expertise with international representation to establish evidence-based guidance on intrathecal drug delivery in treating chronic pain. This Polyanalgesic Consensus Conference (PACC)® project, created more than two decades ago, intends to provide evidence-based guidance for important safety and efficacy issues surrounding intrathecal drug delivery and its impact on the practice of neuromodulation. MATERIALS AND METHODS: Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when PACC® last published guidelines) to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence is scant. RESULTS: The PACC® examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The PACC® recommends best practices regarding intrathecal drug delivery to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

Painful diabetic peripheral neuropathy of the feet: integrating prescription-strength capsaicin into office procedures.

Prescription-strength (8%) capsaicin topical system is a US FDA-approved treatment for painful diabetic peripheral neuropathy of the feet. A 30 min application of the capsaicin 8% topical system can provide sustained (up to 3 months) local pain relief by desensitizing and reducing TRPV1-expressing cutaneous fibers. Capsaicin is not absorbed systemically; despite associated application-site discomfort, capsaicin 8% topical system is well tolerated, with no known drug interactions or contraindications, and could offer clinical advantages over oral options. Capsaicin 8% topical system are not for patient self-administration and require incorporation into office procedures, with the added benefit of treatment compliance. This article reviews existing literature and provides comprehensive, practical information regarding the integration of capsaicin 8% topical systems into office procedures.

Capsaicin 8% topical system is used to treat diabetic nerve pain of the feet. This in-office 30 min application can provide lasting relief of pain (for up to 3 months) by targeting the nerves damaged by diabetes. Since capsaicin acts at the site of diabetic nerve pain without being absorbed into the bloodstream, it is unlikely to interfere with other treatments and has few undesirable effects. Discomfort at the application site is the most commonly reported adverse event. Capsaicin 8% topical system must be applied by a healthcare professional and up to four topical systems can be used per treatment. Incorporating the use of capsaicin 8% topical systems into office procedures can help provide relief for patients living with diabetic nerve pain of the feet and may improve treatment compliance.

Perioperative Use of Ketamine.

PURPOSE OF REVIEW: Postoperative pain continues to be one of the most common challenges following surgeries. Multimodal analgesia has been of particular focus as non-opioid alternatives have been encouraged due to concerns of the opioid epidemic. Ketamine has been an especially useful adjunct in multimodal pain regimens within the past few decades. This article highlights the current use and advances surrounding the perioperative use of ketamine. RECENT FINDINGS: Ketamine has antidepressive effects at subanesthetic doses. Intraoperative ketamine may be beneficial in reducing postoperative depression. Additionally, newer studies are exploring whether ketamine can be useful in reducing postoperative sleep disturbances. Ketamine continues to be a great tool in perioperative pain control, especially during an opioid epidemic. As its use continues to expand and gain more popularity in the perioperative period, more research could shed light on the additional nonanalgesic benefits of ketamine use.

A Review of the Paravertebral Block: Benefits and Complications.

PURPOSE OF REVIEW: Paravertebral nerve blocks (PVB) have experienced a surge over the past 2 decades as improved access to ultrasound has increased ease of performance. The purpose of this review is to identify recent findings with regard to PVB's uses, including benefits, risks, and recommendations. RECENT FINDINGS: PVB is reported as an effective method of analgesia both in intraoperative and postoperative applications, with novel applications showing its potential to replace general anesthesia for certain procedures. The use of PVB as a method of analgesia postoperatively has shown lower opioid usage and faster PACU discharge, when compared to alternative approaches like the intercostal nerve block, erector spinae plane block, pectoralis II block, and patient-controlled analgesia. Thoracic epidural analgesia and a serratus anterior plane block are comparable to PVB and can be used as alternatives. The incidence of adverse events is consistently reported to be very low with few new risks being identified as the use of PVB expands. While there are worthwhile alternatives to PVB, it is an excellent option to consider, particularly for higher-risk patients. For patients undergoing thoracic or breast surgery, PVB can improve opioid usage and shorten the length of stay leading to an overall positive impact on patient recovery and satisfaction. More research is needed to further expand novel applications.

Contrast Spread After Erector Spinae Plane Block at the Fourth Lumbar Vertebrae: A Cadaveric Study.

INTRODUCTION: In recent years, the erector spinae plane block (ESPB) has seen widespread use to treat acute and chronic pain in the regions of the thoracic spine. While limited data suggest its increasing utilization for pain management distal to the thoracic, abdomen and trunk, the anesthetic spread and analgesic mechanism of ESPB at the level of the lumbar spine has not been fully described or understood. METHODS: This is an observational anatomic cadaveric study to assess the distribution of solution following an ESPB block performed at the fourth lumbar vertebrae (L4) using ultrasound guidance to evaluate the spread of a 20 ml solution consisting of local anesthetic and methylene blue. The study was performed in an anatomy lab in a large academic medical center. Following injection of local anesthetic with contrast dye, cadaveric dissection was performed to better understand the extent of contrast dye and to determine the degree of staining to further predict analgesic potential. We reviewed the findings of other ESPB cadaveric studies currently available for comparison. RESULTS: Following cadaveric dissection in an anatomy lab, the contrast dye was observed in the ESP space, and staining was found most cranially at L2 and extending caudally underneath the sacrum. Evaluating the depth of its spread, we found it to be confined to the posterior compartment of the spine sparing the nerve roots bilaterally, which is consistent with the only other cadaveric study of ESPB performed at L4. CONCLUSION: Our results demonstrate the clinical utility of lumbar ESPB where posterior confinement of local anesthesia is preferred. However, further investigation is needed to determine the efficacy of ESPB in lower extremity analgesia which is predicated on ventral nerve root involvement.

A Comprehensive Review of Spinal Cord Stimulator Infections.

Spinal cord stimulator (SCS) is approved to treat various pain conditions and is commonly seen in the chronic pain patient population. Due to the nature of the device and its location, infections associated with SCS have a particularly high morbidity. According to post-market data and medical device reports, 87% of patients receiving SCS implants were given perioperative antibiotics as the implantable neurostimulator or receiver pocket serve as the most common sites of infection. The most common antibiotics for surgical prophylaxis given are first-generation cephalosporins (cefalexin, cefazolin) at the time of implantation. If deep infection is suspected, imaging in the form of CT scan should be obtained as physical exam is not always sufficient. For infections involving the epidural space, vertebra, or intervertebral discs, MRI is the preferred imaging modality. If meningitis is suspected, a lumbar puncture is recommended. Positive cultures can help guide antibiotic therapy.

Platelet-Rich Plasma in the Treatment of Facet Mediated Low Back Pain: A Comprehensive Review.

Background: Facet-mediated pain is a major cause of low back pain and as a result, is a significant cause of morbidity, including disability and reduced functionality. Setting: The present investigation involved a PubMed literature review between June 1, and 2021-January 1, 2022. Methods: We systematically reviewed was carried Pubmed using the search terms "platelet-rich plasma", "inflammatory mediators", "facet arthropathy", "axial back pain", and "leukoreduction". Data extraction and quality assessment were performed by 3 independent reviewers. Out of the studies analyzed 2 were retrospective, while 1 was a prospective study. Results: PRP injections for facet mediated or modulated pain are an alternative to conventional pharmacotherapies and interventional injections/radiofrequency. There are limited numbers of studies in world literature at present. Limitations: Small number of articles in the world literature and small numbers of patients in those published studies. Conclusions: At present, there are limited studies in the literature; however, larger well-designed studies are warranted to precisely understand efficacy, potential side effects and best practice techniques for PRP injections for facet mediated or modulated pain.

Radiofrequency Ablation for the Knee Joint: A Survey by the American Society of Pain and Neuroscience.

Background: Genicular nerve radiofrequency ablation (RFA) is an effective, minimally invasive procedure often used to treat patients with intractable knee pain secondary to knee osteoarthritis and failed knee replacements. The prevalence of knee pain in adults has been estimated to be as high as 40% and is continuously increasing with an aging population. Over the past two decades, proceduralists have adopted variations in patient preparation, procedural steps, and post-operative care for genicular nerve RFA procedures. A survey was dispensed via the American Society of Pain and Neuroscience (ASPN) to gain a popular assessment of common practices for genicular nerve RFA. Methods: A 29 question survey was dispensed via SurveyMonkey to all members of ASPN. Members were able to respond to the survey a single time and were unable to make changes to their responses once the survey was submitted. After responses were compiled, each question was assessed in order to determine common practices for genicular nerve RFA. Results: A total of 378 proceduralists responded to the survey. There was high consensus with the three most commonly targeted nerves. The inferomedial, superomedial, and superolateral genicular branches were treated by 95-96% of respondents, while other targets were less commonly treated. There remains some debate among proceduralists regarding the need for a second diagnostic nerve block and the type of steroid used for diagnostic nerve blocks. Conclusion: Pain physicians use a wide variety of methods to perform genicular nerve ablations. The data offered by the survey show that there is no standardized protocol when it comes to treating knee pain via genicular nerve block and ablation and highlights controversies among proceduralists that ought to serve as the targets of future clinical research aimed at establishing a standardized protocol.

Patients on Buprenorphine Formulations Undergoing Surgery.

PURPOSE OF REVIEW: To review the pharmacology of buprenorphine, the evolution of buprenorphine dosing recommendations, and the current literature regarding its recommendations for the perioperative period. RECENT FINDINGS: There is a consensus that for all surgeries, buprenorphine should be continued throughout the perioperative period. If the surgery is a minimal to mild pain surgery, no dose adjustment is needed. There is no clear consensus regarding moderate to severe pain. With all surgeries, multimodal analgesia should be utilized, with regional anesthesia when possible. Patients taking buprenorphine should continue their buprenorphine perioperatively; whether to decrease or maintain dosing is up for debate. Multimodal analgesia should also be used throughout the perioperative period, and communication between the patient and all provider teams is of the utmost importance to provide adequate analgesia during the perioperative period, as well as to arrange safe analgesia upon discharge.

Transcutaneous Electrical Nerve Stimulation as a Treatment for Neuropathic Cough: A Tolerability and Feasibility Study.

Transcutaneous electrical nerve stimulation (TENS) is a form of electroanalgesia used for neuropathic pain disorders. Refractory chronic cough, or "neuropathic cough," may be physiologically similar to other neuropathic pain conditions. This study explored the tolerability and feasibility of using TENS as a treatment for neuropathic cough. Laryngeal TENS was administered to five subjects with neuropathic cough. One electrode was placed over the lateral thyrohyoid membrane, and a second over the cricothyroid space. A frequency of 120 Hz was applied for 30 min. Participants rated symptoms pre-, during, and post-TENS treatment using a Likert scale. Laryngeal TENS was well tolerated by all subjects. Adverse effects included brief neck discomfort when increasing TENS intensity and an event of mild post-treatment hoarseness. The self-reported scores trended toward a reduction in symptom severity during and after treatment. Controlled trials using this method would elucidate the use of TENS for treatment of patients suffering from chronic cough.

Considerations for Epidural Blood Patch and Other Postdural Puncture Headache Treatments in Patients with COVID-19.

BACKGROUND: A primary concern in the use of EBP in these patients is the possibility of seeding the virus in the CNS. Another important concern is related to the known hypercoagulable state in COVID-19 positive patients and associated organ dysfunction that may alter the metabolism of anticoagulants. The safety of the providers performing the EBP, the position of the patient and choices for image guidance (blind, fluoroscopic) are also key considerations to review. It is also important to explore the current state of knowledge about using allogenic instead of autologous blood as well as emerging techniques to eliminate the coronavirus from the blood. OBJECTIVES: In this article we pose the questions of how to manage PDPH in the COVID-19 positive patient and more specifically, the use of epidural blood patch (EBP). METHODS: Literature review. RESULTS: EBP is usually considered after the failure of conservative and pharmacological treatments. Because of the additional risks of EBP in COVID-19 patients it is important to also consider less traditional pharmacological treatments such as theophylinnes and cosyntropin that may offer some additional benefit for COVID-19 patient. Finally, other interventions other than EBP should also be considered including occipital nerve blocks, sphenopalatine ganglion blocks (infratemporal or transnasal). LIMITATIONS: A narrative review with paucity of literature. CONCLUSION: Going forward, an effective treatment for COVID-19 or a safe vaccine and a deeper understanding of the pathophysiology of the virus will certainly change the risk calculus involved in performing an EBP in a COVID-19 patient.

Preoperative frailty assessment combined with prehabilitation and nutrition strategies: Emerging concepts and clinical outcomes.

Important elements of the preoperative assessment that should be addressed for the older adult population include frailty, comorbidities, nutritional status, cognition, and medications. Frailty has emerged as a plausible predictor of adverse outcomes after surgery. It is present in older patients and is characterized by multisystem physiologic decline, increased vulnerability to stressors, and adverse clinical outcomes. Preoperative preparation may include a prehabilitation program, which aims to address nutritional insufficiencies, modify chronic polypharmacy, and enhance physical and respiratory conditions prior to hospital admission. Special considerations are taken for particularly high-risk patients, where the approach to prehabilitation can address specific, individual risk factors. Identifying patients who are nutritionally deficient allows practitioners to intervene preoperatively to optimize their nutritional status, and different strategies are available, such as immunonutrition. Previous studies have shown an association between increased frailty and the risk of postoperative complications, morbidity, hospital length of stay, and 30-day and long-term mortality following general surgical procedures. Evidence from numerous studies suggests a potential benefit of including a standard assessment of frailty as part of the preoperative workup of older adult patients. Studies addressing validated frailty assessments and the quantification of their predictive capabilities in various surgeries are warranted.

Anesthesia residency training in regional anesthesiology and acute pain medicine: a competency-based model curriculum.

The Accreditation Council for Graduate Medical Education has shifted to competency-based medical education. This educational framework requires the description of educational outcomes based on the knowledge, skills and behaviors expected of competent trainees. It also requires an assessment program to provide formative feedback to trainees as they progress to competency in each outcome. Critical to the success of a curriculum is its practical implementation. This article describes the development of model curricula for anesthesiology residency training in regional anesthesia and acute pain medicine (core and advanced) using a competency-based framework. We further describe how the curricula were distributed through a shared web-based platform and mobile application.

Transversus Abdominis Plane Block for Laparoscopic Hysterectomy Pain: A Meta-Analysis.

OBJECTIVE: Review the analgesic effect of the transversus abdominis plane (TAP) block and its impact on postoperative pain scores and opioid usage for patients undergoing laparoscopic and robotic hysterectomies. METHODS: Systematic review with meta-analysis of randomized controlled trials that compared the effect of TAP block to either placebo or no block on narcotic use (in morphine equivalent units [MEq]) and pain (per visual analog scale) within 24] h after a laparoscopic or robotic hysterectomy for benign or malignant indications. Searches were conducted in PubMed and Embase through May 31, 2019. RESULTS: Nine randomized controlled trials met eligibility criteria; 7 evaluated laparoscopic hysterectomy and 2 robotic hysterectomy. A total of 688 subjects were included (559 laparoscopic hysterectomy, 129 robotic hysterectomy). Opioid consumption was similar in the first 24] h postoperative with or without TAP block (-0.8 MEq; 95% CI, -2.9, 1.3; 8 TAP arms; N] = 395). Pain scores (visual analog scale) were also similar with or without TAP block (-0.01 U; 95% CI, -0.34, 0.32; 10 TAP arms; N] = 636). Neither meta-analysis showed statistical heterogeneity across studies. CONCLUSIONS: The evidence does not support a benefit of TAP block to reduce pain or opioid use for patients receiving laparoscopic or robotic hysterectomies.

Needle-Through-Needle Technique in Lumbar Interlaminar Epidural Steroid Injection: A Case Report.

When performing lumbar epidural steroid injection on obese patients, needle placement can be challenging due to the difficulty in estimating the appropriate needle length to utilize. Often times, the standard 3.5-inch Tuohy needle is too short to reach its target. In our case report, a needle-through-needle technique was attempted in a lumbar interlaminar epidural steroid injection procedure after the initial needle fell short of the epidural space. To avoid removing the initial needle and restarting the procedure using a longer needle, a 20-gauge 6-inch Tuohy needle was inserted into the 17-gauge 3.5-inch Tuohy needle, successfully reaching the epidural space. This technique can facilitate quicker needle placement by avoiding the need for restarting the procedure with a longer needle. Thus, procedural time and radiation exposure may be decreased, as may patient discomfort from repeat needle insertions.

Incidence of vocal cord paresis following ultrasound-guided interscalene nerve block: An observational cohort study.

BACKGROUND: Interscalene brachial plexus block (IBPB) has become a standard practice for perioperative analgesia for shoulder procedures. However, several side effects may occur owing to its anatomic location. We have chosen to evaluate vocal cord paresis and dysphonia following interscalene blocks. METHODS: After IRB approval, eight patients undergoing arthroscopic shoulder procedures were recruited into this prospective cohort study. Following informed consent, vocal cords were assessed by standardized fiberoptic evaluation. Subsequently, IBPB was performed under ultrasound (US) guidance. Patients were re-evaluated for vocal cord changes by a repeat fiberoptic assessment one hour following IBPB. Our primary outcome measure was incidence of vocal cord immobility. RESULTS: No patients had diminished vocal cord motion, dysphonia, or dysphagia. CONCLUSIONS: Although larger studies are required to determine the true incidence of vocal cord paresis following US-guided IBPB, our results suggest that incidence of unwanted nerve blockade other than brachial plexus is much lower than that previously described.

A Comprehensive Review of Analgesia and Pain Modalities in Hip Fracture Pathogenesis.

PURPOSE OF REVIEW: Hip fracture is common in the elderly population, painful and costly. The present investigation was undertaken to review epidemiology, socio-economic and medical implications, relevant anatomy, and anesthetic and pain modalities of hip fracture. RECENT FINDINGS: A literature search of PubMed, Ovid Medline, and Cochrane databases was conducted in December 2018 to identify relevant published clinical trials, review articles, and meta-analyses studies related to anesthetic and pain modalities of hip fracture. The acute pain management in these situations is often challenging. Common issues associated with morbidity and mortality include patients' physiological decrease in function, medical comorbidities, and cognitive impairment, which all can confound and complicate pain assessment and treatment. Perioperative multidisciplinary and multimodal approaches require medical, surgical, and anesthesiology teams employing adequate preoperative optimization. Reduction in pain and disability utilizing opioid and non-opioid therapies, regional anesthesia, patient-tailored anesthetic approach, and delirium prevention strategies seems to ensure best outcomes.

A Randomized Comparison of Pain Control and Functional Mobility between Proximal and Distal Adductor Canal Blocks for Total Knee Replacement.

BACKGROUND: Adductor canal blocks (ACBs) have become a popular technique for postoperative pain control in total knee arthroplasty patients. Proximal and distal ACB have been compared previously, but important postoperative outcomes have yet to be assessed. AIMS: The primary objective of this study is to compare postoperative analgesia between proximal and distal ACB. Secondary outcomes include functional mobility, length of stay (LOS), and adverse events. SETTINGS AND DESIGN: This study was a single-center, assessor-blinded, randomized trial. SUBJECTS AND METHODS: Fifty-seven patients were randomly assigned to receive a proximal (n = 28) or distal (n = 29) ACB. A 20 mL bolus of 5 mg/mL ropivacaine was injected at the respective location followed by 2.0 mg/mL ropivacaine infusion for 24 h. STATISTICAL ANALYSIS: The primary outcome was intra- and postoperative 24-h opioid consumption in intravenous (IV) morphine equivalents. Secondary outcomes include percentage change in timed "Up and Go" (TUG) times, LOS, and average postoperative pain scores. Continuous variables were compared using Student's t-test. RESULTS: The mean (±standard deviation) 24-h intra-and postoperative opioid consumption showed no difference between the proximal and distal groups (39.72 ± 23.6 and 41.28 ± 19.6 mg IV morphine equivalents, respectively, P = 0.793). There was also no significant difference in the median [minimum, maximum] percentage change in TUG times relative to preoperative performance comparing proximal and distal ACB (334.0 [131, 1084] %-change and 458.5 [169, 1696] %-change, respectively, P = 0.130). In addition, there were no differences in postoperative pain scores or LOS. CONCLUSIONS: ACB performed at either proximal or distal locations shows no difference in postoperative pain measured by opioid consumption or pain scores. Better TUG performance seen in the proximal group was not statistically significant but might represent a clinically important difference in functional mobility.

Anticoagulation and Neuraxial/Peripheral Anesthesia.

Novel anticoagulants (NAGs) have emerged as the preferred alternatives to vitamin K antagonists. In patients being considered for regional anesthesia, these drugs present a layer of complexity in the preprocedure evaluation. There are no established tests to monitor anticoagulant activity and our experience is short with these drugs. These authors believe it is important to review the relevant hematology, orthopedics, and anesthesiology literature to provide a valuable reference for the clinician who is met with these challenges. In addition to discussing NAGs, we also review the existing American Society of Regional Anesthesia guidelines for heparin, low-molecular-weight heparin, and antiplatelet agents.