Comparison of ultrasound-guided erector spinae plane block and thoracic paravertebral block for postoperative analgesia after laparoscopic nephrectomy: a randomized controlled non-inferiority clinical trial.

Abstract

Thoracic paravertebral block offers effective analgesia after laparoscopic nephrectomy but has potential severe complication risks. Erector spinae plane block has been described for analgesia after abdominal surgery. However, there are no prospective randomized trials determining if ultrasound-guided erector spinae plane block is non-inferior to thoracic paravertebral block in terms of analgesia after abdominal surgeries including laparoscopic nephrectomy. Sixty-six patients scheduled for laparoscopic nephrectomy were randomized in a 1:1 ratio to receive ultrasound-guided erector spinae plane block (erector spinae plane block group) or thoracic paravertebral block (thoracic paravertebral block group) with 25 mL 0.5% ropivacaine. The primary outcome of this non-inferiority study was the average numerical rating scale score at rest within the first 24 hours following surgery. Secondary outcomes included numerical rating scale scores at rest and while coughing at one, six, 12, 24 and 48 hours postoperatively, total press times of patient-controlled analgesia, time to first press of patient-controlled analgesia, pain rescue, puncture time, the first-attempt success rate to puncture, worst numerical rating scale score during block, dermatomal distribution of sensory blockade, postoperative nausea and vomiting scores, quality of recovery score and time to flatus. Sixty-one subjects, 30 from the erector spinae plane block group and 31 from the thoracic paravertebral block group, completed the study. The median difference (erector spinae plane block minus thoracic paravertebral block) in the primary outcome was 0 (95% CI: 0 to 1). The 95% CI upper limit did not exceed the non-inferiority margin of 1. Numerical rating scale scores at rest at 12 hours and while coughing at six and 12 hours postoperatively were statistically lower in the thoracic paravertebral block group (P=0.04, 0.04 and P<0.05, respectively). There was a shorter puncture time (42.1 s vs. 56.8 s), higher success rate of the first attempt to puncture (83% vs. 58%) and lower pain score during block (2 vs. 3) in the erector spinae plane block group. Other secondary outcomes were similar between groups. This study demonstrates that erector spinae plane block provides non-inferior analgesia for pain at rest within 24 postoperative hours in comparison to thoracic paravertebral block for laparoscopic nephrectomy.