Peripheral nerve block adjuncts: which medication to choose? A narrative review of the current literature.

Enhancing the effect of peripheral nerve blockade by adding other classes of medications has long history of trial and error. Studies have identified multiple potentially beneficial adjuncts that work to either speed the onset of analgesia or prolong its duration. The benefits of these adjuncts must be weighed against the risks of systemic negative side effects. To date, the most commonly used adjuncts, and ones with the most robust scientific efficacy are, dexamethasone, dexmedetomidine and buprenorphine. This narrative review will discuss several classes of local anesthetic adjuncts and provide evidence for the clinical efficacy and side effect profile of the most commonly studied medications.

Percutaneous Neuromodulation of the Brachial Plexus and Sciatic Nerve for the Treatment of Acute Pain Following Surgery: Secondary Outcomes From a Multicenter, Randomized, Controlled Pilot Study.

OBJECTIVES: We recently reported that percutaneous peripheral nerve stimulation (PNS or "neuromodulation") decreased pain and opioid consumption within the first two weeks following ambulatory surgery. However, the anatomic lead locations were combined for the analysis, and benefits for each location remain unknown. We therefore now report the effects of percutaneous PNS for brachial plexus and sciatic nerve leads separately. MATERIALS AND METHODS: Before surgery, leads were implanted percutaneously to target the brachial plexus (N = 21) for rotator cuff repair or sciatic nerve (N = 40) for foot/ankle surgery, followed by a single injection of local anesthetic. Postoperatively, subjects were randomized in a double masked fashion to 14 days of electrical stimulation (N = 30) or sham/placebo (N = 31) using an external pulse generator. The primary outcome of interest was opioid consumption and pain scores evaluated jointly. Thus, stimulation was deemed effective if superior on either outcome and at least noninferior on the other. RESULTS: For brachial plexus leads, during the first seven postoperative days pain measured with the numeric rating scale in participants given active stimulation was a median [interquartile range] of 0.8 [0.5, 1.6] versus 3.2 [2.7, 3.5] in patients given sham (p < 0.001). For this same group, opioid consumption in participants given active stimulation was 10 mg [5, 20] versus 71 mg [35, 125] in patients given sham (p = 0.043). For sciatic nerve leads, pain scores for the active treatment group were 0.7 [0, 1.4] versus 2.8 [1.6, 4.6] in patients given sham (p < 0.001). During this same period, participants given active stimulation consumed 5 mg [0, 30] of opioids versus 40 mg [20, 105] in patients given sham (p = 0.004). Treatment effects did not differ statistically between the two locations. CONCLUSIONS: Ambulatory percutaneous PNS of both the brachial plexus and sciatic nerve is an effective treatment for acute pain free of systemic side effects following painful orthopedic surgery.

Regional anesthesia for breast cancer surgery: which block is best? A review of the current literature.

Breast cancer is the most common type of cancer worldwide. Fortunately, continual advances in diagnosis and treatment are resulting in increased survival rates. Earlier detection and treatment, to include surgical resection, can greatly improve patients outcomes. However, due to the complex innervation of the breast, management of postoperative pain has proven difficult in the past. Approximately, half of all women who undergo breast cancer surgery report postoperative pain syndrome. The paravertebral block has long been the anesthesiologist's choice for mitigating pain during and after the procedure. Newer techniques such as the pectoral nerve block and erector spinae plane block may prove to have some additional benefits. This literature review compares the risks, benefits and specific uses of these three regional nerve blocks in women undergoing breast cancer surgery. It aims to better inform anesthesiologists when they are choosing which technique is best for their patients.

Breast cancer is the most common type of cancer worldwide with 2 million new cases each year. Approximately 12% of women are diagnosed with breast cancer at some point in their lives. Part of breast cancer treatment often involves surgery to remove a mass. This can cause pain in both the short and long term. There are multiple different kinds of procedures a person can have done that may decrease the pain, they have from that surgery. These procedures are called nerve blocks. This article examines how well different nerve blocks decrease pain from breast cancer surgery. The nerve blocks we review in this article are called paravertebral blocks, pectoral nerve blocks and erector spinae plane blocks. They all block pain from breast surgery in slightly different ways. The decision of which block is best rests on the person performing the block.

Percutaneous Peripheral Nerve Stimulation (Neuromodulation) for Postoperative Pain: A Randomized, Sham-controlled Pilot Study.

BACKGROUND: Percutaneous peripheral nerve stimulation is an analgesic technique involving the percutaneous implantation of a lead followed by the delivery of electric current using an external pulse generator. Percutaneous peripheral nerve stimulation has been used extensively for chronic pain, but only uncontrolled series have been published for acute postoperative pain. The current multicenter study was undertaken to (1) determine the feasibility and optimize the protocol for a subsequent clinical trial and (2) estimate the treatment effect of percutaneous peripheral nerve stimulation on postoperative pain and opioid consumption. METHODS: Preoperatively, an electrical lead was percutaneously implanted to target the sciatic nerve for major foot/ankle surgery (e.g., hallux valgus correction), the femoral nerve for anterior cruciate ligament reconstruction, or the brachial plexus for rotator cuff repair, followed by a single injection of long-acting local anesthetic along the same nerve/plexus. Postoperatively, participants were randomized to 14 days of either electrical stimulation (n = 32) or sham stimulation (n = 34) using an external pulse generator in a double-masked fashion. The dual primary treatment effect outcome measures were (1) cumulative opioid consumption (in oral morphine equivalents) and (2) mean values of the "average" daily pain scores measured on the 0 to 10 Numeric Rating Scale within the first 7 postoperative days. RESULTS: During the first 7 postoperative days, opioid consumption in participants given active stimulation was a median (interquartile range) of 5 mg (0 to 30) versus 48 mg (25 to 90) in patients given sham treatment (ratio of geometric means, 0.20 [97.5% CI, 0.07 to 0.57]; P < 0.001). During this same period, the average pain intensity in patients given active stimulation was a mean ± SD of 1.1 ± 1.1 versus 3.1 ± 1.7 in those given sham (difference, -1.8 [97.5% CI, -2.6 to -0.9]; P < 0.001). CONCLUSIONS: Percutaneous peripheral nerve stimulation reduced pain scores and opioid requirements free of systemic side effects during at least the initial week after ambulatory orthopedic surgery.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation: A Pragmatic Effectiveness Trial of a Nonpharmacologic Alternative for the Treatment of Postoperative Pain.

BACKGROUND: Percutaneous peripheral nerve stimulation (PNS) is an analgesic modality involving the insertion of a lead through an introducer needle followed by the delivery of electric current after needle withdrawal. This modality has been used extensively to treat chronic pain, but only small series have been published involving postoperative pain. The ultimate objective of this study is to determine the postoperative effects of percutaneous PNS following moderately to severely painful ambulatory surgery within a real-world clinical practice setting. The primary hypothesis is that surgical pain and opioid consumption during the initial 7 days after surgery will be reduced by percutaneous PNS compared with usual and customary analgesia (dual primary outcome measures). DESIGN: A multicenter pragmatic effectiveness trial. We are randomizing participants having painful orthopedic surgical procedures of the upper and lower extremity to receive 14 days of either 1) electrical stimulation or 2) sham in a double-masked fashion. End points are being assessed at various time points over 12 postoperative months. SUMMARY: The postoperative experience will be much improved if percutaneous PNS provides potent analgesia while concurrently decreasing opioid requirements following painful surgery. Because this modality can be administered for up to 60 days at home, it may provide postoperative analgesia that outlasts surgical pain yet has relatively few risks and, unlike opioids, has no systemic side effects or potential for abuse, addiction, and overdose. Percutaneous PNS has the potential to revolutionize postoperative analgesia as it has been practiced for the past century. This study will inform key stakeholders regarding an evidence-based nonpharmacologic approach to the management of postoperative pain.

Opioid maintenance, weaning and detoxification techniques; where we have been, where we are now and what the future holds: an update.

In 2017, the US Department of Health and Human Services declared a public health emergency on the opioid crisis. On average, 115 Americans die each day from an opioid overdose. The scope and breadth of this problem is continually evolving. In 2010, there was a shift in causes primarily due to the use of heroin, and currently the latest shift in opioid-related deaths involves a variety of synthetic opioids, particularly illicitly manufactured fentanyl. As the medical, sociological and political environments have drastically changed, especially in the USA, over the last 6 years with regard to opioid use and misuse, an updated review of the literature was necessary.

Percutaneous Peripheral Nerve Stimulation for Pain Reduction and Improvements in Functional Outcomes in Chronic Low Back Pain.

Chronic low back pain represents one of the most common sources of disability and a significant healthcare burden for the U.S. military. Present treatments for chronic back pain are often ineffective, poorly tolerated, invasive, destructive, and/or associated with complications and lead to the progression to invasive surgical procedures. There have been multiple calls for the development of a minimally invasive system that is effective without the risks or complications of existing surgical therapies, which could prevent the need for surgery and the recurrence of pain. The goal of this study was to evaluate a novel, minimally invasive approach using a percutaneous peripheral nerve stimulation (PNS) system designed to provide pain relief without surgery, to reduce complications, and provide a less-invasive treatment option. In nine subjects, percutaneous PNS improved participants' function, as evidenced by clinically and statistically significant reductions in pain, disability, and pain interference. Subjects also experienced reductions in opioid and non-opioid analgesic medication usage and reported improvements in quality of life with treatment. There were no serious or unanticipated adverse events. These results demonstrate the potential of percutaneous PNS as a non-surgical therapy to treat chronic back pain without opioids.

A randomized, single-blind, prospective trial of auricular 'battlefield' acupuncture for the reduction of postoperative tonsillectomy pain in adults.

AIM: The purpose of this randomized, single-blind trial was to evaluate the efficacy of battlefield acupuncture in reducing postoperative pain and opioid consumption after adult tonsillectomy. METHODS: Adult participants undergoing a tonsillectomy were randomized to either receive auricular 'battlefield' acupuncture or not. Groups were compared using the Wilcox rank sum test, Fisher's exact test and a generalized estimating equations model for post-discharge pain scores. RESULTS: Statistically significant difference was not noted for morphine equivalent opioid use, nor was there any difference noted in the pain scores between the control group and treatment group. CONCLUSION: Acupuncture is cheap, safe and effective in many settings. Peri-operative battlefield auricular acupuncture did not reduce postoperative pain or opioid consumption in this study.

The feasibility of employing a home healthcare model for education and treatment of opioid overdose using a naloxone auto-injector in a private practice pain medicine clinic.

OBJECTIVES: The purpose of this study was to determine if employing a home healthcare model for education and treatment of opioid overdose using the Evzio (Naloxone) auto-injector in a private practice pain clinic. METHODS: A prospective survey was used to determine the feasibility of integrating a naloxone auto-injector within the patient's home with a home care training model. Twenty moderate or high-risk patients were enrolled from the chronic pain clinic. Patients who were moderate or high risk completed an evaluation survey. The naloxone auto-injector was dispensed to all patients meeting criteria. The treating provider after prescribing the naloxone auto-injector then consulted home health per standard clinical practice. All patients had home health consulted to perform overdose identification and rescue training. A Cochran's Q test was conducted to examine differences in patient knowledge pre- and post-training. The post training test was done 2-4 weeks later. RESULTS: Forty subjects enrolled after meeting inclusion/exclusion criteria. Twenty withdrew because their insurance declined coverage for the naloxone auto-injector. Those completing home health showed a statistically significant difference in their ability to correctly identify the steps needed to effectively respond to an overdose (p = .03). DISCUSSION: Preliminary evidence would suggest training on overdose symptom recognition and proper use of prescription naloxone for treatment in the home setting by home health staff would prove more beneficial than the clinic setting, but feasibility was hindered by unaffordable costs related to insurance coverage limitations.

Acupuncture for the Treatment of Chronic Pain in the Military Population: Factors Associated With Treatment Outcomes.

OBJECTIVES: Acupuncture is characterized as an alternative or complementary medicine with a low complication rate and minimal side effects. There is a lack of robust evidence that shows acupuncture is an effective treatment for chronic pain. The purpose of this study was to determine which (if any) characteristics can predict successful response to acupuncture in chronic pain patients treated at military treatment facilities. METHODS: Data from 222 patients who received treatment for a chronic pain condition were collected from 2 medical centers. The patients underwent at least 4 acupuncture treatments and had an average pain score of 4 or higher on a 0- to 10-point numerical rating scale or visual analog scale in the week before treatment initiation. A successful outcome was defined to be a 2-point or greater reduction on the numerical rating scale or visual analog scale 12 weeks postinitial treatment. RESULTS: The overall treatment success rate was 42.3%. Multivariate logistic regression found a higher baseline pain rating and the use of stimulation needles to be associated with a positive outcome (odds ratio [OR]=1.26; 95% confidence interval [CI], 1.03-1.55; P=0.02 and OR=2.73; 95% CI, 1.39-5.32; P=0.03, respectively). Only the presence of one or more psychological comorbidities was found to be associated with treatment failure (OR=0.67; 95% CI, 0.49-0.92; P=0.01). DISCUSSION: The use of electrical stimulation and higher baseline pain score were associated with a positive treatment outcome, while the presence of a psychological comorbidity diminished the likelihood of treatment success. Practitioners should consider using electrical stimulation more frequently, and addressing psychopathology before or concurrent to treatment, when initiating acupuncture.

An observational feasibility study to assess the safety and effectiveness of intranasal fentanyl for radiofrequency ablations of the lumbar facet joints.

PURPOSE: The purpose of the present observational, feasibility study is to assess the preliminary safety and effectiveness of intranasal fentanyl for lumbar facet radiofrequency ablation procedures. PATIENTS AND METHODS: This cohort observational study included 23 adult patients. Systolic and diastolic blood pressures, heart rate, oxygen saturation percent, Pasero Opioid-Induced Sedation Scale score, and the Defense and Veterans Pain Rating Scale pain score were assessed prior to the procedure and intranasal fentanyl (100 µg) administration and every 15 minutes after administration, up to 60 minutes post administration. Follow-up of patient satisfaction with pain control and treatment was assessed 24 hours after discharge. The primary outcome was safety as evidenced by adverse events. Secondary outcomes included the above-mentioned vital signs and pain ratings. RESULTS: No adverse events occurred in the present study and all participants maintained an acceptable level of awareness throughout the assessment period. One-way repeated measures analyses of covariance tests with Bonferroni-adjusted means indicated that oxygen saturation, blood pressure, and heart rate changed from baseline, whereas pain scores were lower at post-administration levels compared with baseline. Finally, the majority of participants reported being satisfied with pain control and treatment. CONCLUSION: Preliminary evidence indicates that intranasal fentanyl is safe and effective for lumbar facet radiofrequency ablation procedures. Future rigorous randomized control trials are needed to confirm the present results and to examine the effects of intranasal fentanyl on intraoperative and postoperative opioid use.

Determinants of Patient Satisfaction in a Private Practice Pain Management Clinic.

BACKGROUND: Patient satisfaction is used to measure physician performance in hospital and governmental practice settings. There is limited understanding about factors affecting satisfaction in a chronic pain management setting for patients prescribed chronic opioids. OBJECTIVE: To identify the determinants of patient satisfaction and correlation with recommended outcome measures in a private practice pain management clinic. METHODS: We performed a 4-week quality assessment survey to define the determinants of patient satisfaction among pain management patients who were prescribed opioids. The data obtained from the survey were analyzed with descriptive and multiple regression analysis. RESULTS: Overall provider satisfaction was 96% and clinic satisfaction was 94% for a chronic pain population prescribed opioids for over 1 year. There was no correlation between provider satisfaction and functional outcomes. Only "level of stress" correlated with positive clinic satisfaction. The remainder of the functional outcomes were not correlated with satisfaction. "Listened to you carefully about your questions and concerns," "Treated you with courtesy and respect," and "Helped you with your problem" were found to be significant predictors of provider satisfaction. CONCLUSIONS: These results indicate that a patient's perception of a provider's engagement and concern more heavily impacts perceived satisfaction than the patient's progress. A patient's perception of his or her clinic experience is heavily influenced by the attentiveness and coordination of the entire clinic care team. Staff attentiveness and coordination may affect a patient's level of stress. Adherence to current opioid prescription guidelines did not appear to have an overall negative effect on patient satisfaction.

A Preliminary Examination of the Comparative Efficacy of Intravenous vs Oral Acetaminophen in the Treatment of Perioperative Pain.

OBJECTIVE: The management of postoperative pain is a major health care issue. While the cost of intravenous acetaminophen (IVA) is significantly greater than its oral acetaminophen (OA) counterpart, less is known regarding comparative effectiveness of these routes. The purpose of this study was to determine whether perioperative IVA is equivalent in reducing postoperative pain compared with perioperative OA for laparoscopic cholecystectomy (LapChole). DESIGN: Double-blinded, prospective, randomized placebo-controlled trial. SETTING: Womack Army Medical Center, Fort Bragg, North Carolina. SUBJECTS: Adults (age > 18 years) active duty military, veterans, and beneficiaries receiving a laparoscopic cholecystectomy. METHODS: This study was conducted at Womack Army Medical Center (WAMC), Fort Bragg, North Carolina, between January 2013 and June 2015. Sixty-seven subjects with symptomatic cholelithiasis were randomly assigned to receive two doses (1,000 mg each) of either IVA or OA. A numerical rating scale (NRS) score of pain was obtained preoperatively and every six hours for 24 hours postoperation. The primary objective was to assess whether treatment groups had significantly different 24-hour postoperative sum of pain intensity differences (SPID24) using an analysis of covariance test. RESULTS: Sixty subjects completed the study and were included in the analysis. Treatment groups did not differ in SPID24, even when controlling for age, gender, and preoperative pain levels (F(1,55) = 0.39, P = 0.54, partial η2 = 0.007), nor did 24-hour opioid consumption when controlling for age, gender, and operation time (F(1, 46) = 0.47, P = 0.50, partial η2 = 0.01). Furthermore, treatment groups were equally as likely to report average postoperative NRS scores of 4 or higher (ß = 0.24, Exp(B) = 1.28, P = 0.68). CONCLUSIONS: The results show no evidence of differences between IVA or OA in pain or opioid consumption among a sample of patients undergoing LapChole. Due to low sample size, these descriptive findings warrant larger studies, which may have a significant economic impact.

Randomized, double-blind, comparative-effectiveness study comparing pulsed radiofrequency to steroid injections for occipital neuralgia or migraine with occipital nerve tenderness.

Occipital neuralgia (ON) is characterized by lancinating pain and tenderness overlying the occipital nerves. Both steroid injections and pulsed radiofrequency (PRF) are used to treat ON, but few clinical trials have evaluated efficacy, and no study has compared treatments. We performed a multicenter, randomized, double-blind, comparative-effectiveness study in 81 participants with ON or migraine with occipital nerve tenderness whose aim was to determine which treatment is superior. Forty-two participants were randomized to receive local anesthetic and saline, and three 120 second cycles of PRF per targeted nerve, and 39 were randomized to receive local anesthetic mixed with deposteroid and 3 rounds of sham PRF. Patients, treating physicians, and evaluators were blinded to interventions. The PRF group experienced a greater reduction in the primary outcome measure, average occipital pain at 6 weeks (mean change from baseline -2.743 ± 2.487 vs -1.377 ± 1.970; P < 0.001), than the steroid group, which persisted through the 6-month follow-up. Comparable benefits favoring PRF were obtained for worst occipital pain through 3 months (mean change from baseline -1.925 ± 3.204 vs -0.541 ± 2.644; P = 0.043), and average overall headache pain through 6 weeks (mean change from baseline -2.738 ± 2.753 vs -1.120 ± 2.1; P = 0.037). Adverse events were similar between groups, and few significant differences were noted for nonpain outcomes. We conclude that although PRF can provide greater pain relief for ON and migraine with occipital nerve tenderness than steroid injections, the superior analgesia may not be accompanied by comparable improvement on other outcome measures.

Epidural lysis of adhesions for failed back surgery and spinal stenosis: factors associated with treatment outcome.

BACKGROUND: Failed back surgery syndrome (FBSS) is a challenging problem. One treatment advocated to treat FBSS is epidural lysis of adhesions (LOA). The results of studies examining LOA for FBSS have been mixed, but are limited because no study has ever sought to identify factors associated with outcomes. METHODS: We performed this multicenter, retrospective study in 115 patients who underwent LOA for FBSS (n = 104) or spinal stenosis (n = 11) between 2004 and 2007. Twenty-seven demographic, clinical, and procedural variables were extracted from medical records and correlated with the outcome, defined as ≥50% pain relief lasting ≥1 month. Univariable analysis was performed, followed by multivariable logistic regression. RESULTS: Overall, 48.7% (95% confidence interval [CI], 39.3%-58.1%) of patients experienced a positive outcome. In univariable analysis, those who had a positive outcome were older (mean age 64.1 years; 95% CI, 59.7-68.6 vs 57.2; 95% CI, 53.0-61.4 years; P = 0.02), while higher baseline numerical rating scale pain scores were associated with a negative outcome (mean 6.7 years; 95% CI, 6.0-7.3 vs 7.5; 95% CI, 6.9-8.0; P = 0.07). Use of hyaluronidase did not correlate with outcomes in univariable analysis (odds ratio [OR], 1.2; 95% CI, 0.6-2.5; P = 0.65). In multivariable analysis, age ≥81 years (OR, 7.8; 95% CI, 1.4-53.7), baseline numerical rating scale score ≤9 (OR, 4.4; 95% CI, 1.4-16.3, P = 0.02), and patients on or seeking disability or worker's compensation (OR, 4.4; 95% CI, 1.1-19.5, P = 0.04) were significantly more likely to experience a positive outcome. CONCLUSIONS: Considering our modest success rate, selecting patients for epidural LOA based on demographic and clinical factors may help better select treatment candidates. Procedural factors such as the use of hyaluronidase that increase risks and costs did not improve outcomes, so further research is needed before these become standard practice.

A multicenter, randomized, controlled study evaluating preventive etanercept on postoperative pain after inguinal hernia repair.

BACKGROUND: Chronic postsurgical pain (CPSP) affects between 5% and 70% of surgical patients, depending on the surgery. There is no reliable treatment for CPSP, which has led to an increased emphasis on prevention. In this study, we sought to determine whether preventive etanercept can decrease the magnitude of postoperative pain and reduce the incidence of CPSP. METHODS: We performed a multicenter, randomized study in 77 patients comparing subcutaneous etanercept 50 mg administered 90 minutes before inguinal hernia surgery with saline. Patients, surgeons, anesthesiologists, the injecting physician, nursing staff, and evaluators were blinded. The primary outcome measure was a 24-hour numerical rating scale pain score. Secondary outcome measures were postanesthesia care unit pain scores, 24-hour opioid requirements, time to first analgesic, and pain scores recorded at 1 month, 3 months, 6 months, and 12 months. RESULTS: Mean 24-hour pain scores were 3.3 (95% confidence interval [CI], 3.2-4.6) in the etanercept and 3.9 (95% CI, 2.6-4.0) in the control group (P=0.22). The mean number of analgesic pills used in the first 24 hours was 4.0 (SD, 2.8) in the treatment versus 5.8 (SD, 4.2) in the control group (P=0.03). At 1 month, 10 patients (29%) in the treatment group reported pain versus 21 (49%) control patients (P=0.08). The presence of pain at 1 month was significantly associated with pain at 3 months (hazard ratio, 0.74; 99% CI, 0.52-0.97; P=0.03). CONCLUSION: Although preventive etanercept was superior to saline in reducing postoperative pain on some measures, the effect sizes were small, transient, and not statistically significant. Different dosing regimens in a larger population should be explored in future studies.

Opioid maintenance, weaning and detoxification techniques: where we have been, where we are now and what the future holds.

SUMMARY Medically supervised opioid withdrawal is a complex and constantly evolving exercise in multimodal therapy that draws from the expertise of a variety of clinical specialties. Acute substitution and weaning has been performed utilizing opioid agonists, partial agonists (e.g., buprenorphine), mixed agonist/antagonists (e.g., Suboxone®), and α2 adrenergic agonists. While thousands of patients are being treated with these 'classic' opioid-withdrawal techniques, traditional treatment approaches are being challenged by the emergence of innovative techniques based on an understanding of the neurochemistry of addiction. Pharmacotherapy with controlled withdrawal is currently the most reliable method of opioid detoxification, but, as translational medicine continues to advance and genomic markers for opioid sensitivity and dependence are identified, the future shows great potential for growth and change.

The application of genomic and molecular data in the treatment of chronic cancer pain.

Many cancer patients will develop complex pain syndromes requiring aggressive, innovative, and comprehensive multimodal pain management strategies. Recently, data from both animal studies and clinical trials have allowed clinical research to focus on creating applicable clinical treatment strategies. This article is a review of genomic and molecular data, which has contributed to creating novel modalities for use in clinical pain management of patients with cancer-induced pain.