Background and Aims Percutaneous Nephrolithotomy (PCNL) is associated with moderate to severe postoperative pain. Thoracic paravertebral block (TPVB and ultrasound-guided (USG) interfascial plane block can effectively reduce postoperative pain following PCNL. Newer interfascial plane blocks: Erector Spinae Plane Block (ESPB), and Costotransverse Foramen Block (CTFB), both single and multiple-level injections, have shown wide dermatomal spread and provide adequate analgesia. We hypothesize that triple-level USG-ESPB has analgesic efficacy not inferior to triple-level USG-CTFB in patients undergoing PCNL.

Methods This prospective randomized, double-blind, inferiority trial was conducted after ethics committee approval. Fifty patients scheduled for PCNL were included in the trial. Patients received either triple-level USG-ESPB or triple-level USG-CTFB. Seven ml of 0.375% Ropivacaine at each level (21ml.) was injected for either block after induction of anaesthesia in the prone position. Total analgesic requirement (total cumulative morphine consumption in 24 hours), intraoperative analgesic requirement, time for the first analgesic, and 11-point NRS at various intervals for 24 hours were noted.

Results Median cumulative morphine consumption in 24 hours was 7mg (4-11.75 mg) and 7mg (3-11 mg) in ESPB and CTPB groups, respectively (P=.26). The mean time for the first analgesic requirement in the postoperative period in ESPB group was 189.8 ± 80.2 minutes and 199.6 ± 79.8 minutes in CTFB group (P=.66). No significant difference in the median NRS scores at rest and at movement at various time-intervals were observed. No adverse event was observed.

Conclusions Our study demonstrated that in patients undergoing Percutaneous Nephrolithotomy, triple-level USG-ESPB is not inferior to triple Level USG-CTFB in providing postoperative analgesia.