BackgroundThe thoracic retrolaminar block (TRLB) is a relatively new regional analgesia technique that can be used as an alternative to the thoracic paravertebral block. This study aimed to evaluate the postoperative analgesia effects of ultrasound-guided TRLB in children undergoing open cardiac surgery via median sternotomy incision.MethodsSixty-six patients aged 2–8 years were recruited. In the TRLB group, 0.25% bupivacaine 0.4 ml/kg was injected into the retrolaminar space on both sides at the level of the T4 lamina. Patients in the control group were injected with 0.9% saline. The primary outcome measure was fentanyl consumption in the first 24 h post-extubation. The secondary outcome measures were the total intraoperative fentanyl consumption, postoperative modified objective pain score (MOPS), and time to extubation.ResultsThe total intraoperative fentanyl requirements and fentanyl consumption in the first 24 h post-extubation were significantly lower (P < 0.001) in the TRLB group (9.3 ± 1.2; 6.9 ± 2.1 μg/kg, respectively) than in the control group (12.5 ± 1.4; 16.6 ± 2.8, respectively). The median (Q1, Q3) time to extubation was significantly shorter (P < 0.001) in the TRLB group (2 [1, 3] h) than in the control group (6 [4.5, 6] h). The MOPS was significantly lower (P < 0.05) in the TRLB group than in the control group at 0, 2, 4, 8, 12 and 16 h post-extubation. ConclusionsBilateral ultrasound-guided TRLB is effective in providing postoperative analgesia in children undergoing open cardiac surgery via median sternotomy incision.