Management of pain with regional analgesia

Nerve block efficacy in breast augmentation: A systematic review and meta-analysis

Breast augmentation is often performed as a day-case general anaesthetic operation, with postoperative, opioid-based analgesia regimens. However, it may also be performed using regional anaesthesia; a variety of nerve block techniques are available to reduce postoperative pain and analgesic requirements. This systematic review and meta-analysis were undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines comparing breast augmentation using regional anaesthesia with general anaesthesia, versus general anaesthesia alone or with local field infiltration. All randomised or quasi-randomised studies that recruited adult female patients undergoing breast augmentation using regional anaesthesia were considered. The primary outcome measures were postoperative pain and analgesic requirements. A randomised effects model was used, with standardised mean difference or mean difference outcomes used as appropriate. Thirteen studies were included for systematic review, out of which eight met the inclusion criteria for meta-analysis. Nerve blocks had statistically significant standardised mean difference reductions in postoperative pain scores across all time points: 0 h (-1.2 [-2.1 to -0.3], p = 0.01, I2 = 85%), 1 h (-1.3 [-2.1 to -0.5], p = 0.002, I2 = 89%), 2 h (-1.8 [-2.8 to -0.9], p = 0.0002, I2 = 88%), 4-6 h (-1.2 [-2.1 to -0.4], p = 0.006, I2 = 89%), 24 h (-1.4 [-2.5 to -0.2], p = 0.02, I2 = 94%). There was also a statistically significant reduction in postoperative opioid requirements: -150 mcg fentanyl (-259.2 to -40.9), p = 0.007. Although an element of study heterogeneity is noted, this systematic review and meta-analysis support the concept that regional anaesthesia using nerve blocks in breast augmentation surgery, reduces both postoperative pain and opioid requirements, compared with general anaesthesia.

Efficacy of Intra-articular Versus Extra-articular Bupivacaine Injection in Arthroscopic Partial Meniscectomy: A Prospective, Randomized, Double-Blind Clinical Trial

Background

Immediate postoperative pain relief following arthroscopic partial meniscectomy remains a critical contributor to improved patient experience, early recovery of range of motion, and enhanced rehabilitation.

Purpose

To evaluate the effect of intra-articular versus extra-articular bupivacaine on pain intensity and analgesic intake after arthroscopic partial meniscectomy.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

This was a prospective double-blind, randomized clinical trial. All patients included underwent arthroscopic partial meniscectomy under general anesthesia. Patients were randomized into 2 groups, with 20 patients in each group. At the conclusion of the arthroscopic procedure, the intra-articular group received 10 mL 0.5% bupivacaine introduced intra-articularly and 10 mL isotonic saline 0.9% infiltrated subcutaneously around the portals. The extra-articular group received the isotonic saline intra-articularly and the bupivacaine around the portals. The primary outcome was the visual analog scale (VAS) for pain. Assessments were performed 0 to 0.5, 1 to 2, 2 to 4, and at 24 and 48 hours postoperatively. In addition, analgesic and narcotic consumption was monitored.

Results

There were no differences between the groups in terms of patient demographics. VAS scores for the intra-articular group were 6, 8, 3.25, 4.3, and 4.5 at 0 to 0.5, 1 to 2, 2 to 4, 24, and 48 hours postoperatively, respectively. VAS scores for the extra-articular group were 3.8, 5, 2.9, 5.2, and 5.25, respectively. No statistically significant differences were observed between the 2 groups regarding pain intensity at all time points. There was also no statistically significant difference in analgesic consumption. Dipyrone was the preferred drug by patients from the intra-articular group, while the extra-articular group preferred to use opioids and nonsteroidal anti-inflammatory drugs.

Conclusion

There were no differences in pain severity and analgesic intake between intra- or extra-articular bupivacaine administration after arthroscopic partial meniscectomy.

Effectiveness and safety of massage for chronic pain in patients with knee osteoarthritis: A protocol for systematic review and meta-analysis

BACKGROUND

Chronic pain (CP) is a common and debilitating symptom in patients with knee osteoarthritis (KOA). Massage has been supported as a non-pharmacological intervention for the individual symptom relief of CP. However, relevant evidence of using massage for CP in patients with KOA has been lacking.

METHODS

A systematic search will be performed in the following electronic databases for randomized controlled trials to evaluate the effectiveness and safety of massage for CP of KOA: China National Knowledge Infrastructure (CNKI), Wan Fang, PubMed, EMBASE, PsycINFO, and the Cochrane Library databases from their inception to December 2021. The entire process will include study selection, data extraction, risk of bias assessment and meta-analysis.

RESULTS

This proposed study will evaluate the effectiveness and safety of massage for CP in patients with KOA. Changes in pain relief and adverse effect will be included in our outcomes.

CONCLUSIONS

This systematic review will provide evidence for assessing the credibility of massage for CP in patients with KOA.

DISSEMINATION AND ETHICS

The results of this review will be disseminated through peer-reviewed publication. This review does not require ethical approval because all of the data used in this systematic review and meta-analysis have already been published. Furthermore, all of these data will be analyzed anonymously during the review process.

Nav1.7 and other voltage-gated sodium channels as drug targets for pain relief

Introduction: Chronic pain is a massive clinical problem. We discuss the potential of subtype selective sodium channel blockers that may provide analgesia with limited side effects.

Areas covered: Sodium channel subtypes have been linked to human pain syndromes through genetic studies. Gain of function mutations in Na_v1.7, 1.8 and 1.9 can cause pain, whilst loss of function Na_v1.7 mutations lead to loss of pain in otherwise normal people. Intriguingly, both human and mouse Na_v1.7 null mutants have increased opioid drive, because naloxone, an opioid antagonist, can reverse the analgesia associated with the loss of Na_v1.7 expression.

Expert Opinion: We believe there is a great future for sodium channel antagonists, particularly Na_v1.7 antagonists in treating most pain syndromes. This review deals with recent attempts to develop specific sodium channel blockers, the mechanisms that underpin the Na_v1.7 null pain-free phenotype and new routes to analgesia using, for example, gene therapy or combination therapy with subtype specific sodium channel blockers and opioids. The use of selective Na_v1.7 antagonists together with either enkephalinase inhibitors or low dose opioids has the potential for side effect-free analgesia, as well as an important opioid sparing function that may be clinically very significant.

Opioids and TRPV1 in the peripheral control of neuropathic pain--Defining a target site in the injured nerve

Targeting peripheral neuropathic pain at its origin may prevent the development of hypersensitivity. Recently we showed this can be mediated by opioid receptors at the injured nerve trunk. Here, we searched for the most relevant peripheral site to block transient receptor potential vanilloid 1 (TRPV1), and investigated analgesic interactions between TRPV1 and opioids in neuropathy. In a chronic constriction injury (CCI) of the sciatic nerve in mice, we assessed the effects of μ-, δ- and κ-opioid receptor agonists and TRPV1 antagonist (SB366791) injected at the CCI site or into the injured nerve-innervated paw on spontaneous paw lifting, heat and mechanical sensitivity. We also examined TRPV1 expression in total membrane and plasma membrane fractions from nerves and paws. We found that opioids and SB366791 co-injected in per se nonanalgesic doses at the CCI site or into the paw diminished heat and mechanical sensitivity. SB366791 alone dose-dependently alleviated heat and mechanical sensitivity. TRPV1 blockade in the paw was more effective than at the CCI site. None of the treatments diminished spontaneous paw lifting. TRPV1 expression analysis suggests that the levels of functional TRPV1 do not critically determine the TRPV1 antagonist-mediated analgesia. Together, the identification of the primary action site in damaged nerves is crucial for effective pain control. Contrary to opioids, the TRPV1 blockade in the injured nerve peripheral terminals, rather than at the nerve trunk, appears promising against heat pain. Opioid/TRPV1 antagonist combinations at both locations partially reduced neuropathy-triggered heat and mechanical pain.

Intraarticular vs. extraarticular ropivacaine infusion following high-dose local infiltration analgesia after total knee arthroplasty: a randomized double-blind study

BACKGROUND AND PURPOSE

Ropivacaine infusion following high-volume local infiltration analgesia has been shown to be effective after total knee arthroplasty, but the optimum site of administration of ropivacaine has not been evaluated. We compared the effects of intraarticular and extraarticular adminstration of the local anesthetic for postoperative supplementation of high-volume local infiltration analgesia.

PATIENTS AND METHODS

In this double-blind study, 36 rheumatic patients aged 51-78 years with physical status ASA 2-3 who were scheduled for total knee arthroplasty were randomized into 2 groups. All patients received wound infiltration at the end of surgery with 300 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine (total volume 156 mL). A tunneled catheter was randomly placed either extraarticularly or intraarticularly. Continuous infusion of ropivacain (0.5%, 2 mL/h) was started immediately and was maintained during the next 48 h. Pain intensity at rest, on movement, and with mobilization was estimated by the patients and the physiotherapist; rescue morphine consumption was recorded.

RESULTS

As estimated by the patients, ropivacaine administered intraarticularly did not improve analgesia relative to extraarticular infusion, but improved the first mobilization. The incidence of high intensity of pain (VAS 7-10) was less in the group with intraarticular infusion. Analgesic requirements were similar in the 2 groups (47 mg and 49 mg morphine). No complications of postoperative wound healing were seen and there were no toxic side effects.

INTERPRETATION

Continuous infusion of ropivacaine intraarticulary did not improve postoperative analgesia at rest relative to extraarticular administration, but it appeared to reduce the incidence of high pain intensity during first exercises, and could therefore be expected to improve mobilization up to 24 h after total knee arthroplasty.

The epidemiology of pain in the prehospital setting

OBJECTIVE

To develop national estimates of the epidemiology of pain in the prehospital setting.

METHODS

Cross-sectional data on a probability sample of 21,103 emergency department (ED) visits from the 1999 National Hospital Ambulatory Medical Care Survey were analyzed. For patients arriving by ambulance, the frequencies (95% confidence intervals) of patients presenting with no level of pain reported (data unknown or missing) and those reporting no, mild, and moderate or severe pain were determined. The reasons for visit among those with moderate or severe pain, and the ED narcotic analgesic use among those with pain information reported and not reported, were also determined.

RESULTS

Of the 102.8 million patients visiting the ED in 1999, 14.5 million arrived by ambulance. Fifty-three percent (49-58%) were female. Seven million six hundred thousand [52% (48-56%)] had no information on presenting level of pain reported, 2.0 million [14% (2-25%)] had no pain, 2.0 million [14% (3-25%)] had mild pain, and 2.9 million 120% (12-29%)] had moderate or severe pain. Among those with moderate or severe pain, the most common reasons for visit were injuries 27% (11-43%) and non-injury musculoskeletal symptoms 18% (0-39%). Narcotic analgesics were ordered or continued in 13% (0-29%) of those with no presenting level of pain recorded and 21% (9-34%) of those for whom the presenting level of pain was recorded.

CONCLUSION

Pain is a common condition among prehospital patients: 20% reported moderate to severe pain. Given the use of narcotic analgesics among those for whom pain information was not reported, this is likely a conservative estimate.

Emergency Medical Services Outcomes Project (EMSOP) IV: pain measurement in out-of-hospital outcomes research

The purpose of the Emergency Medical Services Outcomes Project (EMSOP) is to develop a foundation and framework for out-of-hospital outcomes research. In prior work (EMSOP I), discomfort had the highest weighted score among outcome categories for the top 3 adult conditions (ie, minor trauma, respiratory distress, chest pain) and the first and third highest rankings for children's conditions (ie, minor trauma, respiratory distress). In this fourth article in the EMSOP series, we discuss issues relevant to the measurement of pain in the out-of-hospital setting, recommended pain measures that require evaluation, and implications for outcomes research focusing on pain. For adults, adolescents, and older children, 2 verbal pain-rating scales are recommended for out-of-hospital evaluation: (1) the Adjective Response Scale, which includes the responses "none," "slight," "moderate," "severe," and "agonizing," and (2) the Numeric Response Scale, which includes responses from 0 (no pain) to 100 (worst pain imaginable). The Oucher Scale, combining a visual analog scale with pictures, seems most promising for out-of-hospital use among younger children. Future research in out-of-hospital care should be conducted to determine the utility and feasibility of these measures, as well as the effectiveness of interventions for pain relief.