Abstract
Background: Achieving optimal abdominal analgesia with few side effects is the goal of pain management after cesarean delivery. Intrathecal morphine is the current standard but ultrasound guided quadratus lumborum block (US-QLB) may offer superior pain control with fewer side effects. This study compared the pain-free period after cesarean delivery among parturients who received spinal block with IT morphine 0.2 mg, with IT morphine 0.2 mg and bilateral QLB, or only bilateral QLB.Methods: Parturients having elective cesarean delivery with a low transverse incision under spinal block were randomized to three groups. Subjects were allocated into IT morphine 0.2 mg with sham QLB (Group IT morphine), IT morphine 0.2 mg and bilateral QLB with 0.25% bupivacaine 25 ml and adrenaline 1:250,000 in each side (Group IT morphine with QLB), or bilateral QLB with 0.25% bupivacaine 25 ml and adrenaline 1:250,000 in each side (Group QLB). A PCA pump was connected to each parturient after completion of the QLB or sham block. The first time to PCA morphine requirement when parturients experienced pain was recorded and compared.Results: Eighty parturients were included. Analysis of Group QLB was terminated early because Kaplan-Meier survival analysis showed the median pain-free period to be significantly shorter in Group QLB at the second interim analysis; [2.50 hours (95% CI: 1.04-3.96) in Group IT morphine vs. 7.75 (95% CI: 5.67-9.83) in Group IT morphine with QLB vs. 1.75 (95% CI: 0.75-2.75) in Group QLB (overall p<0.001)]. The median (min, max) amount of morphine required during 24 hours was 5.5 (0-25) in Group IT morphine vs. 5.0 (0-36) in Group IT morphine with QLB vs. 17.5 (1-40) mg in Group QLB (p<0.001). In the final analysis the median pain-free period was 2.50 hours (95%CI: 1.23-3.77) in Group IT morphine (n=27) and 8.02 (95%CI: 5.96-10.07) in Group IT morphine with QLB (n=28). (Gehan-Breslow p=0.027).Conclusion: US-QLB used in conjunction with IT morphine yielded a statistically significant longer median pain-free period compared with standard IT morphine alone. However, QLB alone provided inferior pain control compared with standard IT morphine. When combined with IT morphine, QLB may provide additional analgesic benefit as a part of multimodal analgesic regimen, especially during the early postoperative period.Trial registration: ClinicalTrials.gov no. NCT03199170 Date registered on June 22, 2017. Prospectively registered.
Ultrasound-guided bilateral quadratus lumborum block vs. intrathecal morphine for postoperative analgesia after cesarean section: a randomized controlled trial
