Clarke, Hance

Abstract Objective To evaluate available evidence for the efficacy and safety of topical analgesics for neuropathic pain and to offer treatment guidance. Methods An expert panel searched PubMed (Medline) and reference lists of published articles for available literature assessing 8 categories of topical analgesics used to treat various neuropathic pain conditions. The panel rated the level of analgesic efficacy evidence for each treatment and considered safety, ease of use, and cost. The degree of consensus on the recommendations among the panelists was measured. Results There was strong evidence and high consensus that capsaicin 8% is effective for diabetic peripheral neuropathy and postherpetic neuralgia and that lidocaine is effective for postherpetic neuralgia. There was strong evidence and moderate consensus that capsaicin 8% could be effective for HIV-induced neuropathy. There was moderate evidence and high consensus that lidocaine is likely effective for diabetic peripheral neuropathy, idiopathic neuropathy, and postsurgical neuropathy and that capsaicin 8% might be effective for chemotherapy-induced peripheral neuropathy and complex regional pain syndrome. Evidence was weak for other topical medications, though the panel strongly agreed that antidepressants might help with postherpetic neuralgia, complex regional pain syndrome, postsurgical neuropathy, and post-traumatic neuropathy; that nonsteroidal anti-inflammatory drugs could help with postsurgical neuropathy; and that gabapentin might benefit vulvodynia. There was less agreement about whether antidepressants might benefit diabetic peripheral neuropathy, chemotherapy-induced peripheral neuropathy, and vulvodynia and whether capsaicin 8% could be effective for postsurgical neuropathy. Conclusions Recommendations were based on a survey and grading of existing literature and, when strong evidence was lacking, the collective clinical expertise of panelists.

Summary Non‐steroidal anti‐inflammatory drugs (NSAIDs) are one of the mainstays of multimodal pain management. While effective for acute pain control, recent pre‐clinical evidence has raised concerns regarding an association between NSAIDs and chronic pain and potential opioid use. Our objective was to explore the association between peri‐operative use of prescription NSAIDs and the need for continued opioid prescriptions lasting 90–180 days in previously opioid‐naïve patients undergoing total knee arthroplasty. A database of health claims in the USA was used to identify all opioid‐naïve adult patients who underwent primary knee arthroplasty between January 2010 and October 2021. We evaluated the magnitude of association between peri‐operative prescription NSAID claims and claims for opioids at 90 days postoperatively using multivariable logistic regression models. Secondary outcomes included: the magnitude of association between peri‐operative NSAID prescription and claims for opioids at 180 days postoperatively; and identifying other potential factors associated with opioid claims at 90 days postoperatively. After risk adjustment using multivariable logistic regression models in the 789,736‐patient cohort, the adjusted odds ratio (95%CI) for a continuous claim of opioids at 90 and 180 days postoperatively among patients with a peri‐operative NSAID prescription within 30 days was 1.32 (1.30–1.35), p < 0.001; and 1.12 (1.10–1.15), p < 0.001, respectively. This estimate of effect remained robust at 90 days after accounting for known potential confounders, including pre‐existing knee pain and acute postoperative pain severity. Similar analysis of other pain medications (e.g. paracetamol) did not detect such an association. This population‐based cohort study suggests that peri‐operative prescription NSAID use may be associated with continued opioid prescription claims at 90 and 180 days after knee arthroplasty, even after adjusting for other observed covariates for continuous opioid claims. These novel findings can inform clinical decision‐making for post‐surgical pain management, risk–benefit discussions with patients and future research.

Background The past two decades have seen an increase in cannabis use due to both regulatory changes and an interest in potential therapeutic effects of the substance, yet many aspects of the substance and their health implications remain controversial or unclear. Methods In November 2020, the American Society of Regional Anesthesia and Pain Medicine charged the Cannabis Working Group to develop guidelines for the perioperative use of cannabis. The Perioperative Use of Cannabis and Cannabinoids Guidelines Committee was charged with drafting responses to the nine key questions using a modified Delphi method with the overall goal of producing a document focused on the safe management of surgical patients using cannabinoids. A consensus recommendation required ≥75% agreement. Results Nine questions were selected, with 100% consensus achieved on third-round voting. Topics addressed included perioperative screening, postponement of elective surgery, concomitant use of opioid and cannabis perioperatively, implications for parturients, adjustment in anesthetic and analgesics intraoperatively, postoperative monitoring, cannabis use disorder, and postoperative concerns. Surgical patients using cannabinoids are at potential increased risk for negative perioperative outcomes. Conclusions Specific clinical recommendations for perioperative management of cannabis and cannabinoids were successfully created.

AbstractBackgroundPost‐operative pain management is a critical component of perioperative care. Patients at risk of poorly controlled post‐operative pain may benefit from early measures to optimize pain management. We sought to identify risk factors for post‐operative pain and opioid consumption in patients undergoing liver resection.MethodsThis is a multi‐institutional prospective nested cohort study of patients undergoing open liver resection. Opioid consumption and pain scores were collected following surgery. To estimate the effects of patient factors on opioid consumption (oral morphine equivalents—OME) and on pain scores (NRS‐11), we used generalized linear models and multivariable linear regression model, respectively.ResultsOne hundred and fifty‐three patients who underwent open liver resection between 2013 and 2016 were included in the study. The mean patient age was 62.2 years, and 43.3% were female. Younger patients were significantly more likely to use more opioids in the early post‐operative period (16.7 OME/10 years, p < 0.001). Patient factors that were significantly associated with increased NRS‐11 pain scores also included younger patient age (difference in pain score of 0.3/10 years with cough and 0.2/10 years at rest, p < 0.01 for both) as well as a history of analgesic use (difference in pain score of 0.9 with cough and 0.6 at rest, p < 0.01 and p = 0.07, respectively).ConclusionYounger patients and those with a history of analgesic use are more likely to report higher post‐operative pain and require higher doses of opioids. Early identification of these patients, and measures to better manage their pain, may contribute to optimal perioperative care.

AbstractBackgroundThe study aims were to model acute pain intensity and opioid consumption trajectories up to 72 hr after open hepatic resection, identify predictors of trajectory membership and examine the association between trajectory memberships and 6‐month pain and psychological outcomes. This is a long‐term analysis of a published randomized controlled trial on the impact of medial open transversus abdominis plane catheters on post‐operative outcomes.MethodsA total of 152 patients (89 males; mean age 63.0 [range: 54–72]) completed questionnaires on pain and related characteristics pre‐operatively and 6 months post‐operatively. Total opioid use was recorded several times over a 72‐hr period while self‐reported pain intensity scores were collected multiple times until hospital discharge. Analyses were carried out using growth mixture modelling, logistic regression and general linear models.ResultsBoth pain intensity and opioid consumption showed that a four‐trajectory model best fits the data. Patients in the lowest opioid consumption trajectory were more likely to be classified in the constant mild pain intensity trajectory. Age and baseline levels of anxiety significantly predicted opioid trajectory membership while baseline depressive symptoms significantly predicted pain intensity trajectory membership. Patients in the two highest opioid consumption trajectories reported significantly higher levels of pain catastrophizing at 6 months compared to patients in the other 3 trajectories (all p < 0.05).ConclusionHigh consumption of opioids after surgery is associated with higher levels of pain catastrophizing 6 months later. Identification of patients within these trajectories may lead to the development of early interventions targeted to high risk individuals.SignificanceDifferences in initial levels of opioid consumption and rates of change in opioid consumption shortly after surgery can help predict long‐term psychological responses to pain. Identifying key characteristics associated with initial opioid consumption can lead to the development of cost‐effective early interventions targeted to high risk individuals.

Objective: Conventional management of pain following open liver resection involves intravenous, patient-controlled analgesia (IV PCA) or epidural analgesia. The objective of this trial was to assess the efficacy of a regional technique called Medial Open Transversus Abdominis Plane (MOTAP) catheter analgesia compared with IV PCA. Methods: This was a blinded, randomized, controlled parallel-arm trial conducted at 2 high-volume centers. Patients undergoing liver resection through a subcostal incision were enrolled. Using a standardized technique, 2 catheters were placed after resection: one in the plane between internal oblique and transversus abdominis and the other in the posterior rectus sheath. Patients were randomized to receive ropivacaine 0.2% (ROP) or saline (NS) through both catheters for 72 hours. All patients received IV PCA with hydromorphone as part of a multimodality analgesia program. Primary outcome was opioid use over the first 48 hours. Results: One hundred fifty-three patients were included in the analysis (71 ROP, 82 NS). Patients receiving ROP used significantly less opioid than patients with NS at 48 hours (median 39.6 mg morphine-equivalent vs 49.2 mg, P = 0.033) and at 72 hours (median 50.0 vs 66.4 mg, P = 0.046). Pain scores at rest and with coughing were significantly lower at all time points in patients who received ROP (P = 0.002). Median length of hospital stay was 5 days in patients receiving ROP and 6 days in patients who received NS (P = 0.035). There was no difference between groups in complications [ROP 20 (28.2%) vs NS 26 (31.7%), P = 0.63]. Conclusion: MOTAP catheter analgesia reduces opioid requirements, pain, and length of hospital stay compared with IV PCA following open liver resection with subcostal incisions.