Literature Review: August 2023
Cite as: Machi A, Oweidat A. Literature review - August 2023. ASRA Pain Medicine News 2023;48. https://doi.org/10.52211/asra080123.012.
Editor’s note: “Literature Review” is a feature designed to provide you with brief summaries of recent articles of interest, particularly from sources that our readers might not normally consume.
Acute Pain
The Analgesic Effect of Transmuscular Quadratus Lumborum Block Versus Erector Spinae Plane Block for Women Undergoing Elective Caesarean Section: A Randomized Controlled Trial
Mostafa M et al. Br J Pain 2023; 0(0). Online ahead of print. https://doi.org/10.1177/20494637231181513
Summary by Marcelle Blessing, MD
Introduction: The optimal regional anesthetic for analgesia after cesarean section is unclear. This study compares the analgesia and quality of recovery for two fascial plane blocks, transmuscular quadratus lumborum (QLB) and erector spinae plane block (ESPB) for elective cesarean section.
Methods: In this prospective randomized controlled trial, 153 women having elective cesarean sections under spinal anesthesia without intrathecal morphine were randomized into three groups: 51 women were randomized to receive bilateral QLB, 51 women were randomized to receive bilateral thoracic ESPB, and a control group of 51 women received no block. Patients in all groups received multimodal anesthesia. The study’s primary outcome was time to first use of the rescue analgesic, intravenous morphine. Secondary outcomes included total postoperative morphine consumption and score on the total Obstetric Quality of Recovery-11 (ObsQoR-11).
Results: 149 women (48, 50, and 51 in the control, ESPB and QLB groups, respectively) were included in the final analysis. Time to first morphine request was longer for the QLB and ESPB groups than the control group (median [quartiles] time: 6 [6,12] h, 6 [6,6] h and 4 [3,4] h, respectively; p-value <0.001). Total morphine consumption was lower in the QLB and ESPB groups than in the control group (p<0.001). The ObsQor-11 was higher for both block groups than in the control group. Results for the primary and secondary outcomes were comparable for the QLB and ESPB groups.
Key Point: Transmuscular QLB and ESPB produced similar and better pain control and quality of recovery than spinal anesthesia alone.
Efficacy of Ultrasound-Guided Thoracic Paravertebral Block on Postoperative Quality of Recovery in Patients Undergoing Percutaneous Nephrolithotomy: A Randomized Double-Blind Placebo-Controlled Trial
Yan Z et al. J Pain Res 2023; 16: 1301-10. https://doi.org/10.2147/JPR.S405657
Summary by Beth VanderWielen, MD
Introduction: Despite the minimally invasive nature of a percutaneous nephrolithotomy (PCNL), the lithotripsy tract that is created can cause patients significant post-operative pain. Patients’ quality of recovery after PCNL is yet to be well described in the literature. The aim of this study was to determine if a single-shot T11 thoracic paravertebral block (PVB) would improve the overall patient experience while secondarily decreasing opioid consumption.
Methods: In this double-blind placebo-controlled study, 78 patients were randomized to receive a preoperative T11 thoracic PVB with either 20 cc of 0.5% ropivacaine or 0.9% saline. Patients then underwent general anesthesia for their procedure. A morphine patient-controlled intravenous analgesia was utilized for post-operative pain control. Twenty-four hours post-operatively, patients completed a 15-item Quality of Recovery questionnaire (QoR- 15 score), which scored pain, physical comfort, physical independence, psychological support, and emotional state on a 0-10 numeric rating scale (NRS). Secondary outcomes included NRS pain and intensity scores, time to first rescue analgesia, and overall patient satisfaction.
Results: The median QoR-15 score in the thoracic PVB group compared to the saline group was significantly higher (127 (IQR, 117-133) vs. 114 (IQR, 109-122), 95% CI, 5-14, P<0.001). NRS pain scores were lower both at rest and with activity in the PVB group and sustained up to 12 hours post-operatively (P<0.001); no difference was found at 24-hours (P=0.062). The median time to first rescue analgesia was longer in the PVB group (10.8 h, IQR 7.1-22.8 h vs 1.9 h, IQR 0.5-4.3h, P<0.001) with approximately a 50 percent reduction in morphine use compared to the saline control (19 mg (IQR, 2-28 mg) vs 37 mg (IQR, 26-52 mg), P<0.001).
Key Point: A single injection thoracic PVB may be helpful to improve patients’ quality of recovery and limit opioid consumption after a PCNL.
Pectoral Fascial Plane Versus Paravertebral Blocks for Minimally Invasive Mitral Valve Surgery Analgesia
Vinzant N et al. JCVA. 2023;37(7)1188-94. https://doi.org/10.1053/j.jvca.2023.02.012
Summary by Jeffrey Grzybowski, MD
Introduction: Mitral valve repairs and replacements in the United States performed through minimally invasive techniques have nearly doubled in the past decade. Current emphasis on enhanced recovery protocols has led to increased interest in less-invasive regional techniques, such as the pectoral fascial plane (PECS) I and II blocks. Robust evidence demonstrating safety and efficacy of PECS blocks in minimally invasive cardiac surgery is lacking.
Methods: This retrospective study evaluated patients undergoing minimally invasive robotic mitral valve surgery, who received either ultrasound-guided paravertebral or PECS II blocks for postoperative analgesia. Right-sided paravertebral blocks were performed preoperatively with 10 mL of 0.5% bupivacaine at each of the T2, T4, and T6 levels. Right-sided PECS II blocks were performed postoperatively in supine, anesthetized patients. 20 mL of 0.25% bupivacaine were injected in the pectoserratus plane with 10 mL of 0.25% bupivacaine injected in the interpectoral plane. During closure, surgeons performed multilevel intercostal nerve blocks with 1.3% liposomal bupivacaine in all patients. Primary outcome measures were average postoperative pain scores and cumulative opioid use.
Results: 313 patients were analyzed, of whom 123 (39%) received a PECS II block, and 190 (61%) received a paravertebral block. With paravertebral block as the reference group, the estimated multiplicative change in cumulative opioid consumption through 24 hours was 0.70 (95% CI 0.54-0.91; p=0.007), indicating patients who received a PECS II block required approximately 30% fewer opioids during this time interval. Similarly, the estimated multiplicative change in cumulative opioid consumption through 12 hours was 0.62 (95% CI 0.46-0.83; p=0.002), through 48 hours was 0.75 (95% CI 0.59-0.96; p=0.022), and through 72 hours was 0.74 (95% CI 0.57-0.97; p=0.028). Pain scores and secondary outcomes did not differ significantly between groups.
Key Point: PECS II blocks represent a safe and effective alternative to paravertebral blocks in providing postoperative analgesia for minimally invasive robotic mitral valve surgery.
Chronic Pain
Psychological and Neurological Predictors of Acupuncture Effect in Patients with Chronic Pain: A Randomized Controlled Neuroimaging Trial
Wang X, Li JL, Wei XY, et al. Pain 2023;164(7):1578-92. https://doi.org/10.1097/j.pain.0000000000002859
Summary by Mohammad R. Rasouli, MD
Introduction: Acupuncture can be an effective treatment for chronic osteoarthritis; however, various factors may affect patients’ response. Identifying these variables is of great clinical value for selecting patients who may benefit from acupuncture. This study aimed to identify psychological and neuroimaging predictors of response to acupuncture in patients with knee osteoarthritis.
Methods: This single, blind, randomized controlled trial was performed in a Beijing University hospital. Respectively, 27 and 25 patients were analyzed in the acupuncture and sham acupuncture groups. Patients received 12 sessions of 30-minute treatment for 4 weeks. In the sham group, blunt needles were inserted into an adhesive pad over non-acupoints. The primary outcome was changes on the numeric pain rating scale (NRS). Psychological questionnaires and brain MRIs were used to measure psychological and neuroimaging variables. Subcortical striatum (a structure that plays role in chronic pain) volume, cortical thickness, fractional amplitude of low frequency fluctuation (fALFF) [indicator of spontaneous brain activity], and small-worldness network (small-world topology of short path length and high clustering that reflects structural and functional connectivity in the brain) were determined. A machine learning model was used to predict response to acupuncture using these variables.
Results: Acupuncture was associated with larger NRS changes at 4 weeks (Effect size= 0.9, p= 0.002). Positive expectation, extraversion, and emotional attention were identified as psychological predictors of response to acupuncture.
Striatal volumes, posterior cingulate cortex cortical thickness, striatal fALFF, and graph-based small-worldness of the default mode network were also associated with response to acupuncture. The machine learning model predicted response to acupuncture with an accuracy of 81.48%.
Key Point: The observed psychological factors could be used for patient selection and predicting response to acupuncture in patients with knee osteoarthritis.
Efficacy, Safety, and Tolerability of Antidepressants for Pain in Adults: Overview of Systematic Reviews
Ferreira GE, Abdel-Shaheed C, Underwood M, et al. BMJ 2023;380:e072415. https://doi.org/10.1136/bmj-2022-072415
Summary by Bhavana Yalamuru, MBBS
Introduction: Chronic pain is debilitating and affects one in five people globally. Considering the increasing use of antidepressants to treat chronic pain of various etiologies, the authors conducted an overview of systematic reviews to appraise efficacy estimates for each condition individually.
Methods: This is an overview of systematic reviews, comparing any antidepressant with placebo for adults with chronic pain conditions. PubMed, Embase, PsycINFO, and the Cochrane Central Register of Controlled Trials were searched from inception to June 20, 2022, and each review was reviewed by two reviewers. Pain relief was considered the primary outcome with frequency of headaches for headache disorders. Secondary outcomes were safety and tolerability. Findings were classified from each comparison as efficacious, not efficacious, or inconclusive. The data was then reported by each pain condition and antidepressant class. An antidepressant was considered efficacious for a condition when the difference between intervention and placebo groups was statistically significant, favoring the antidepressant, and the certainty of evidence was at least low.
Results: Selective norepinephrine reuptake inhibitors (SNRIs) showed efficacy in back pain, postoperative pain, fibromyalgia, and neuropathic pain (moderate evidence). Low- grade evidence was observed for the following: Selective serotonin reuptake inhibitors (SSRIs) for depression and comorbid chronic pain; tricyclic antidepressants (TCAs) for neuropathic pain, pain with irritable bowel syndrome and chronic tension type headache; and SNRIs for knee osteoarthritis, depression comorbid with chronic pain, and aromatase inhibitor therapy induced pain in breast cancer. SSRIs were not efficacious for back pain, fibromyalgia, functional dyspepsia, and non-cardiac chest pain. TCA’s were not efficacious for functional dyspepsia.
Key Point: Based on the review results, a nuanced and thoughtful approach should be applied while prescribing antidepressants for pain with careful consideration given to the etiology of pain as well as the antidepressant class used.
Cognitive Functional Therapy With or Without Movement Sensor Biofeedback Versus Usual Care for Chronic, Disabling Low Back Pain (RESTORE): A Randomized, Controlled, Three-arm, Parallel Group, Phase 3, Clinical Trial
Kent P, Haines T, O’Sullivan P, et al. Lancet 2023;401(10391):1866-77. https://doi.org/10.1016/S0140-6736(23)00441-5
Summary by Priyanka Singla, MD
Introduction: Chronic low back pain is one of the biggest causes of absenteeism, disability, and financial burden on any healthcare system. The aim of this study was to compare the effectiveness and economic efficiency of individualized cognitive functional therapy (CFT), delivered with or without movement sensor biofeedback, with usual care.
Methods: RESTORE was a randomized controlled trial. In both CFT groups, participants received up to seven treatment sessions over 12 weeks plus a booster session at 26 weeks. Trained physiotherapists created an individualized treatment plan by re-conceptualizing patient’s pain from a biopsychosocial perspective, developing healthy lifestyle behaviors, and providing functional behavioral change through graded exposure to movements. Movement sensor's data was used for retraining in the biofeedback group. The primary clinical outcome was self-reported physical activity limitation using the 24-point Roland Morris Disability Questionnaire at 13 weeks. The primary economic outcome was quality-adjusted life-years (QALYs).
Results: 492 patients were randomized to the three groups. Both interventions were more effective than usual care (CFT only mean difference –4·6 [95% CI –5·9 to –3·4, p<0.0001] and CFT plus biofeedback mean difference –4·6 [–5·8 to –3·3, p<0.0001]) for activity limitation at 13 weeks, which was sustained at 52 weeks. Both interventions were less costly than usual care for QALYs, –AU$5276 [–10 529 to –24) for the CFT only group and –AU$8211 (–12 923 to –3500) for the CFT plus biofeedback group. Adding a sensor was not beneficial.
Key Point: CFT is a cost-effective therapy for sustained improvement in patients with chronic disabling back pain when compared to usual care.
