Quadratus lumborum block for postoperative pain after caesarean section: A randomised controlled trial.

BACKGROUND: Effective postoperative analgesia after caesarean section is important because it enables early ambulation and facilitates breast-feeding. Several case reports have shown that local anaesthetic injection around the quadratus lumborum muscle is effective in providing pain relief after various abdominal operations and in patients with chronic pain. The quadratus lumborum block (QLB) is performed in close proximity to the surface and uses a fascial compartment path to extend the distribution of local anaesthesia into the posterior abdominal wall and paravertebral space. This central effect can be of vital importance when managing the visceral pain after caesarean section.

OBJECTIVE: We hypothesised that the QLB after caesarean section can provide adequate pain relief as part of a multimodal approach.

DESIGN: Double-blind, randomised and controlled clinical trial.

SETTING: A single centre between June 2014 and December 2014.

PATIENTS: Fifty patients who were American Society of Anesthesiologists physical status 1 or 2, with normal singleton pregnancies with a gestation of at least 37 weeks, and scheduled for elective caesarean section under spinal anaesthesia, were enrolled into the study. They were randomly assigned to receive a QLB (n = 25) with 0.125% bupivacaine 0.2 ml kg⁻¹ (Group 1) or a QLB (n = 25) with 0.9% Normal saline 0.2 ml kg⁻¹ (Group 2).

MAIN OUTCOME MEASURES: The primary outcome measure for the study was the morphine demands and doses delivered by a patient-controlled analgesia system at predetermined intervals (1, 2, 4, 6, 12, 24 and 48 h) after surgery. The secondary endpoints were visual analogue scale (VAS) for pain at rest and on movement (dynamic), heart rate, blood pressure, pruritus, itching, nausea, vomiting and sedation.

RESULTS: The patients who received local anaesthetic used significantly less morphine than the control group (P < 0.001) at 6 and 12 h, but not at 24 and 48 hours after caesarean section. The local anaesthetic group had significantly less morphine demand than the control group (P < 0.001) 6, 12, 24 and 48 h after caesarean section. The VAS was significantly lower in the local anaesthetic group than the control group, including VAS for pain at rest at all times except 24 h after caesarean section, and VAS for pain on movement (dynamic) at all times.

CONCLUSION: The QLB after caesarean section was effective and provided satisfactory analgesia in combination with a typical postoperative analgesic regimen.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02328378.