K. R. Kirkham

The Impact of Analgesic Modality on Early Ambulation Following Total Knee Arthroplasty

Introduction Total knee arthroplasty is associated with moderate to severe pain, and effective analgesia is essential to facilitate postoperative recovery. This retrospective cohort study examined the analgesic and rehabilitation outcomes associated with 48-hour continuous femoral nerve block, local infiltration analgesia, or local infiltration analgesia plus adductor canal nerve block. Methods Patients undergoing total knee arthroplasty under spinal anesthesia, during an 8-month period, were retrospectively assessed with a targeted review of 100 patients per group. Records of eligible patients were reviewed to identify the analgesic technique used and the primary outcome of distance walked on postoperative day 1. Secondary outcomes included ambulation on days 2 and 3, numeric rating scale pain scores, opioid consumption, and adverse effects and discharge disposition. Results Two hundred ninety-eight eligible patients were reviewed. Local infiltration analgesia and local infiltration plus adductor canal block were associated with longer distances walked on postoperative day 1 than continuous femoral nerve block (median values of 20, 30, and 0 m, respectively; P < 0.0001). The addition of adductor canal block was associated with further improvement in early ambulation benchmarks and a higher rate of home discharge compared with only local infiltration (88.2% vs 73.2%, P = 0.018). Local infiltration with or without adductor canal block was associated with lower pain scores at rest and during movement for the first 24 hours and lower opioid consumption than continuous femoral nerve infusion. Conclusions Local infiltration analgesia was associated with improved early analgesia and ambulation. The addition of adductor canal nerve block was associated with further improvements in early ambulation and a higher incidence of home discharge.

Peri-operative intravenous administration of magnesium sulphate and postoperative pain: a meta-analysis

Intravenous magnesium has been reported to improve postoperative pain; however, the evidence is inconsistent. The objective of this quantitative systematic review is to evaluate whether or not the peri‐operative administration of intravenous magnesium can reduce postoperative pain. Twenty‐five trials comparing magnesium with placebo were identified. Independent of the mode of administration (bolus or continuous infusion), peri‐operative magnesium reduced cumulative intravenous morphine consumption by 24.4% (mean difference: 7.6 mg, 95% CI −9.5 to −5.8 mg; p < 0.00001) at 24 h postoperatively. Numeric pain scores at rest and on movement at 24 h postoperatively were reduced by 4.2 (95% CI −6.3 to −2.1; p < 0.0001) and 9.2 (95% CI −16.1 to −2.3; p = 0.009) out of 100, respectively. We conclude that peri‐operative intravenous magnesium reduces opioid consumption, and to a lesser extent, pain scores, in the first 24 h postoperatively, without any reported serious adverse effects.

A systematic review and meta-analysis of perineural dexamethasone for peripheral nerve blocks.

We systematically reviewed the safety and efficacy of perineural dexamethasone as an adjunct for peripheral nerve blockade in 29 controlled trials of 1695 participants. We grouped trials by the duration of local anaesthetic action (short‐ or medium‐ vs long‐term). Dexamethasone increased the mean (95% CI) duration of analgesia by 233 (172–295) min when injected with short‐ or medium‐term action local anaesthetics and by 488 (419–557) min when injected with long‐term action local anaesthetics, p < 0.00001 for both. However, these results should be interpreted with caution due to the extreme heterogeneity of results, with I2 exceeding 90% for both analyses. Meta‐regression did not show an interaction between dose of perineural dexamethasone (4–10 mg) and duration of analgesia (r2 = 0.02, p = 0.54). There were no differences between 4 and 8 mg dexamethasone on subgroup analysis.

The Analgesic Efficacy of Ultrasound-Guided Transversus Abdominis Plane Block in Adult Patients: A Meta-Analysis.

BACKGROUND:Previous meta-analyses of the transversus abdominis plane (TAP) block have examined a maximum of 12 articles, including fewer than 650 participants, and have not examined the effect of ultrasound-guided techniques specifically. Recently, many trials that use ultrasound approaches to TAP block have been published, which report conflicting analgesic results. This meta-analysis aims to evaluate the analgesic efficacy of ultrasound-guided TAP blocks exclusively for all types of abdominal surgeries in adult patients. METHODS:This meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. The primary outcome was cumulative IV morphine consumption at 6 hours postoperatively, analyzed according to the type of surgery, the type of surgical anesthesia, the timing of injection, the block approach adopted, and the presence of postoperative multimodal analgesia. Secondary outcomes included IV morphine consumption at 24 hours postoperatively; pain scores at rest and on movement at 6 and 24 hours postoperatively; and postoperative nausea and vomiting, pruritus, and rates of complications. RESULTS:Thirty-one controlled trials including 1611 adult participants were identified. Independent of the type of surgery (abdominal laparotomy, abdominal laparoscopy, and cesarean delivery) but not independent of the type of surgical anesthesia (general anesthesia, spinal anesthesia with or without intrathecal long-acting opioid), ultrasound-guided TAP block reduced IV morphine consumption at 6 hours postoperatively by a mean difference of 6 mg (95% confidence interval [CI], −7 to −4 mg; I2 = 94%; P < 0.00001). The magnitude of the reduction in morphine consumption at 6 hours postoperatively was not influenced by the timing of injection (I2 = 0%; P = 0.72), the block approach adopted (I2 = 0%; P = 0.72), or the presence of postoperative multimodal analgesia (I2 = 73%; P = 0.05). This difference persisted at 24 hours postoperatively (mean difference, −11 mg; 95% CI, −14 to −8 mg; I2 = 99%; P < 0.00001). Pain scores at rest and on movement were reduced at 6 hours postoperatively (mean difference at rest, −10; 95% CI, −15 to −5; I2 = 92%; P = 0.0002; mean difference on movement, −9; 95% CI, −14 to −5; I2 = 58%; P < 0.00001). There were neither differences in the incidence of postoperative nausea and vomiting (I2 = 1%; P = 0.59) nor in the pruritus (I2 = 12%; P = 0.58) Two minor complications (1 bruise and 1 anaphylactoid reaction) were reported in 1028 patients. CONCLUSIONS:Ultrasound-guided TAP block provides marginal postoperative analgesic efficacy after abdominal laparotomy or laparoscopy and cesarean delivery. However, it does not provide additional analgesic effect in patients who also received spinal anesthesia containing a long-acting opioid. The minimal analgesic efficacy is independent of the timing of injection, the approach adopted, or the presence of postoperative multimodal analgesia. Because of heterogeneity of the results, these findings should be interpreted with caution.

The analgesic efficacy and safety of neuraxial magnesium sulphate: a quantitative review

Eighteen published trials have examined the use of neuraxial magnesium as a peri‐operative adjunctive analgesic since 2002, with encouraging results. However, concurrent animal studies have reported clinical and histological evidence of neurological complications with similar weight‐adjusted doses. The objectives of this quantitative systematic review were to assess both the analgesic efficacy and the safety of neuraxial magnesium. Eighteen trials comparing magnesium with placebo were identified. The time to first analgesic request increased by 11.1% after intrathecal magnesium administration (mean difference: 39.6 min; 95% CI 16.3–63.0 min; p = 0.0009), and by 72.2% after epidural administration (mean difference: 109.5 min; 95% CI 19.6–199.3 min; p = 0.02) with doses of between 50 and 100 mg. Four trials monitored for neurological complications: of the 140 patients included, only a 4‐day persistent headache was recorded. Despite promising peri‐operative analgesic effect, the risk of neurological complications resulting from neuraxial magnesium has not yet been adequately defined.

The analgesic efficacy of local infiltration analgesia vs femoral nerve block after total knee arthroplasty: a systematic review and meta-analysis

Many consider femoral nerve block the gold standard in pain management following knee arthroplasty. Local infiltration analgesia is an alternate approach that applies the concept of surgical wound infiltration with local anaesthetics. This meta-analysis aims to compare both analgesic treatments for analgesia and functional outcomes after total knee arthroplasty. This meta-analysis was performed according to the PRISMA statement guidelines. The primary outcomes were cumulative i.v. morphine consumption, pain scores at rest and on movement on postoperative day one (analogue scale,0-10). Secondary outcomes included range of motion, quadriceps muscle strength, length of stay and rates of complications (neurologic events, cardiovascular events, falls and knee infections). Fourteen trials, including 1122 adult patients were identified. There was no difference in i.v. morphine consumption (mean difference: -2.0 mg; 95% CI: -4.9, 0.9 mg; I(2)=69%; P=0.19), pain scores at rest (mean difference: -0.1; 95% CI: -0.4, 0.3; I(2)=72%; P=0.80) and pain scores on movement (mean difference: 0.2; 95% CI: -0.5, 0.8; I(2)=80%; P=0.64) on postoperative day one (a negative mean difference favours local infiltration analgesia). The qualities of evidence for our primary outcomes were moderate according to the GRADE system. There were no clinical differences in functional outcomes or rates of complications. Complication rates were captured by three trials or fewer with exception of knee infection, which was sought by eight trials. Local infiltration analgesia provides similar postoperative analgesia after total knee arthroplasty to femoral nerve block. Although this meta-analysis did not capture any difference in rates of complications, the low number of trials that specifically sought these outcomes dictates caution.

The maximum effective needle-to-nerve distance for ultrasound-guided interscalene block: an exploratory study.

One of the most fundamental, 1 yet controversial, tenets of regional anesthesia practice has been the adage “no paresthesia, no anesthesia.” Implicit to this concept is the requirement for direct needle-nerve contact to achieve a successful block. The advent of ultrasound (US) guidance for peripheral nerve blockade (PNB) has enabled providers to position the needle tip purposefully as close as possible to, and even inside, the target nerve. Consequently, much of the contemporary regional anesthesia literature has focused on the question “How close is too close?” while investigators challenge the safety limits of US-guided PNB. Regrettably, the risk of nerve injury persists despite US guidance and is underscored by reports of new functional deficits after interscalene brachial plexus block (ISB) performed under US guidance by experienced providers. Given that mechanical needle-nerve trauma is an important mechanism of peripheral nerve injury, providers are cautioned to avoid intentional intraneural injection or needle-nerve contact during US-guided PNB.8,14,15 Potentially hazardous needleto-nerve proximity may be especially relevant during US-guided ISB, where inadvertent injection beneath the epineurium may be as high as 50%. Subepineural, and particularly intrafascicular, injection of local anesthetic may increase the risk of nerve injury.17 Neural elements of the interscalene brachial plexus are predominantly comprised of axonal tissue and may be especially

Preoperative testing before low-risk surgical procedures

Background: There is concern about increasing utilization of low-value health care services, including preoperative testing for low-risk surgical procedures. We investigated temporal trends, explanatory factors, and institutional and regional variation in the utilization of testing before low-risk procedures. Methods: For this retrospective cohort study, we accessed linked population-based administrative databases from Ontario, Canada. A cohort of 1 546 223 patients 18 years or older underwent a total of 2 224 070 low-risk procedures, including endoscopy and ophthalmologic surgery, from Apr. 1, 2008, to Mar. 31, 2013, at 137 institutions in 14 health regions. We used hierarchical logistic regression models to assess patient- and institution-level factors associated with electrocardiography (ECG), transthoracic echocardiography, cardiac stress test or chest radiography within 60 days before the procedure. Results: Endoscopy, ophthalmologic surgery and other low-risk procedures accounted for 40.1%, 34.2% and 25.7% of procedures, respectively. ECG and chest radiography were conducted before 31.0% (95% confidence interval [CI] 30.9%–31.1%) and 10.8% (95% CI 10.8%–10.8%) of procedures, respectively, whereas the rates of preoperative echocardiography and stress testing were 2.9% (95% CI 2.9%–2.9%) and 2.1% (95% CI 2.1%–2.1%), respectively. Significant variation was present across institutions, with the frequency of preoperative ECG ranging from 3.4% to 88.8%. Receipt of preoperative ECG and radiography were associated with older age (among patients 66–75 years of age, for ECG, adjusted odds ratio [OR] 18.3, 95% CI 17.6–19.0; for radiography, adjusted OR 2.9, 95% CI 2.8–3.0), preoperative anesthesia consultation (for ECG, adjusted OR 8.7, 95% CI 8.5–8.8; for radiography, adjusted OR 2.2, 95% CI 2.1–2.2) and preoperative medical consultation (for ECG, adjusted OR 6.8, 95% CI 6.7–6.9; for radiography, adjusted OR 3.6, 95% CI 3.5–3.6). The median ORs for receipt of preoperative ECG and radiography were 2.3 and 1.6, respectively. Interpretation: Despite guideline recommendations to limit testing before low-risk surgical procedures, preoperative ECG and chest radiography were performed frequently. Significant variation across institutions remained after adjustment for patient- and institution-level factors.

The analgesic efficacy of sciatic nerve block in addition to femoral nerve block in patients undergoing total knee arthroplasty: a systematic review and meta-analysis.

The aim of this meta‐analysis was to assess the postoperative analgesic efficacy of sciatic nerve block when combined with femoral nerve block after total knee arthroplasty. Outcomes included resting pain scores (analogue scale, 0–100), intravenous morphine consumption at 12 h, 24 h and 48 h postoperatively, and functional outcomes comprising knee flexion, distance walked, and length of stay. Twelve randomised controlled trials were included, with a total of 600 patients. When combined with femoral nerve block, sciatic nerve block significantly reduced resting pain scores at 12 h postoperatively with a mean difference of 10 (95% CI: −15 to −5; p < 0.00001). Resting pain scores at 24 h, and intravenous morphine consumption at 12 h, 24 h and 48 h postoperatively were also significantly reduced, but without clinical significance beyond 12 h and without affecting functional outcomes. In conclusion, sciatic nerve block confers additional postoperative analgesia within the first 12 postoperative hours compared with femoral nerve block alone for patients undergoing total knee arthroplasty.

Preoperative Laboratory Investigations: Rates and Variability Prior to Low-risk Surgical Procedures.

Background:Increasing attention has been focused on low-value healthcare services. Through Choosing Wisely campaigns, routine laboratory testing before low-risk surgery has been discouraged in the absence of clinical indications. The authors investigated rates, determinants, and institutional variation in laboratory testing before low-risk procedures. Methods:Patients who underwent ophthalmologic surgeries or predefined low-risk surgeries in Ontario, Canada, between April 1, 2008, and March 31, 2013, were identified from population-based administrative databases. Preoperative blood work was defined as a complete blood count, prothrombin time, partial thromboplastin, or basic metabolic panel within 60 days before an index procedure. Adjusted associations between patient and institutional factors and preoperative testing were assessed with hierarchical multivariable logistic regression. Institutional variation was characterized using the median odds ratio. Results:The cohort included 906,902 patients who underwent 1,330,466 procedures (57.1% ophthalmologic and 42.9% low-risk surgery) at 119 institutions. Preoperative blood work preceded 400,058 (30.1%) procedures. The unadjusted institutional rate of preoperative blood work varied widely (0.0 to 98.1%). In regression modeling, significant predictors of preoperative testing included atrial fibrillation (adjusted odds ratio [AOR], 2.58; 95% CI, 2.51 to 2.66), preoperative medical consultation (AOR, 1.68; 95% CI, 1.65 to 1.71), previous mitral valve replacement (AOR, 2.33; 95% CI, 2.10 to 2.58), and liver disease (AOR, 1.69; 95% CI, 1.55 to 1.84). The median odds ratio for interinstitutional variation was 2.43. Conclusions:Results of this study suggest that testing is associated with a range of clinical covariates. However, an association was similarly identified with preoperative consultation, and significant variation between institutions exists across the jurisdiction.