Analgesic Effect of Ultrasound-Guided Caudal Block Versus Quadratus Lumborum Plane Block in Lumbar Spine Surgery in Adult Patients: A Double-Blinded Prospective Comparative Study.

BACKGROUND

Postoperative pain following lumbar spine surgery (LSS) can significantly impact recovery and patient satisfaction. Ultrasound-guided regional techniques such as quadratus lumborum plane block (QLPB) and caudal block (UGCB) have been proposed to enhance postoperative analgesia while reducing opioid consumption and opioid-related adverse effects (AEs).

OBJECTIVES

To compare the analgesic efficacy and safety of ultrasound-guided QLPB versus ultrasound-guided caudal block in adult lumbar spine stabilization surgery.

METHODS

This randomized, double-blinded, prospective comparative study included 111 adult patients (18 - 60 years, ASA physical status I - II) scheduled for elective lumbar spine stabilization surgery. Patients were randomly allocated into three equal groups: Control (standard analgesia), ultrasound-guided caudal block (UGCB), or ultrasound-guided QLPB. Blocks were performed under ultrasound guidance after induction of general anesthesia using 0.25% bupivacaine. The primary outcome was the time to first postoperative rescue analgesia. Secondary outcomes included postoperative pain scores using the Numerical Pain Rating Scale (NPRS), total 24-hour postoperative opioid (meperidine) consumption, intraoperative opioid requirements, hemodynamic variables, and block- or opioid-related adverse events over the first 24 postoperative hours.

RESULTS

The time until the initial rescue analgesia was significantly delayed with QLPB in comparison to control and Caudal, with medians of 15, 1, and 5 h, respectively (P < 0.001). The total 24-hour (meperidine) intake was significantly diminished with QLPB as opposed to Caudal and control (P < 0.05). Numerical Pain Rating Scale scores were significantly diminished in QLPB and Caudal as opposed to control at 30 min, 1, 2, 4, 8, and 24 h (P < 0.001), with comparability detected at 12 h and 18 h. Intraoperative fentanyl administration was markedly diminished in the QLPB and Caudal groups, in contrast to the control group (P < 0.001). The occurrence of nausea and vomiting exhibited comparability across groups.

CONCLUSIONS

Both ultrasound-guided caudal block and QLPB significantly improved postoperative analgesia compared with standard analgesic management following lumbar spine stabilization surgery. However, QLPB provided longer-lasting analgesia and was associated with lower postoperative opioid consumption than caudal block, highlighting its advantage for prolonged postoperative pain control.