Abstract
BACKGROUND: Intrathecal morphine is the mainstay for post-Caesarean multimodal analgesia but is associated with important side-effects. Novel ultrasound-guided abdominal wall fascial plane blocks are proposed as intrathecal morphine alternatives, but evidence of effectiveness is conflicting. We compared the analgesic effects of fascial plane blocks with those of intrathecal morphine after Caesarean delivery. METHODS: We sought trials comparing the analgesic effects of intrathecal morphine with quadratus lumborum (QL), transversus abdominus plane (TAP), or erector spinae plane (ESP) blocks after Caesarean delivery. The primary outcome was rest pain intensity at 6 h on a visual analogue scale (VAS) ranging from 0 to 10 cm, with 10 cm indicating severe pain. Secondary outcomes included pain at 12 and 24 h; cumulative 24-h opioid consumption in milligrams of oral morphine; times to first analgesic request, ambulation, and breast feeding in hours; lengths of recovery room and hospital stay in hours; incidence of opioid-related side-effects; and block-related complications. RESULTS: Eighteen trials (1525 subjects) were included. TAP block was evaluated in 11 studies, QL block in five, and ESP block in two. Intrathecal morphine was superior to TAP block for pain at 6 and 12 h, with mean differences (Hartung-Knapp-Sidik-Jonkman [HKSJ] 95% confidence interval [CI]) of 1.21 cm (0.42-2.00) (P=0.01, I(2)=80%) and 1.03 cm (0.05-2.01) (P=0.04, I(2)=86%), respectively. There were no differences in pain at 6 or 12 h between QL or ESP block compared with intrathecal morphine. Both TAP block and QL block reduced the odds of nausea and vomiting by 0.41 (0.21-0.79) (P=0.01) and 0.33 (0.23-0.48) (P=0.002), respectively, compared with intrathecal morphine. There were no differences in other outcomes. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) certainty of evidence was low across these pooled outcomes. CONCLUSIONS: Quadratus lumborum block, rather than erector spinae or transversus abdominus plane blocks, may be a better intrathecal morphine alternative owing to similar post-Caesarean analgesic effects and reduced opioid-related side-effects. SYSTEMATIC REVIEW PROTOCOL: CRD42024543371.