Ultrasound-guided erector spinae plane block versus paravertebral block for postoperative analgesia in mastectomy and immediate breast reconstruction: a randomized non-inferiority trail

Purpose Immediate breast reconstruction (IBR) after mastectomy improves aesthetic and psychological outcomes in breast cancer patients, but is associated with significant pain. The paravertebral block (PVB) is the current gold standard, but the erector spinae plane block (ESPB) may offer comparable analgesia with technical simplicity and improved safety. Methods A total of hundred patients undergoing mastectomy with subpectoral IBR were randomized to receive either ESPB or PVB. Primary endpoints were highest Numerical Rating Scale (NRS) pain scores and opioid consumption in the post-anesthesia care unit (PACU). Secondary outcomes were block success rate; ease of procedure; length of PACU stay; highest reported NRS and total opioid dose administered in the ward; incidence of complications of the block and patient satisfaction. Results ESPB did not meet non-inferiority criteria compared with PVB in the PACU for highest NRS (difference 1.0; 95% CI 0.1–1.9; p = 0.032) or opioid use (difference 2 mg morphine equivalent (MEQ)); 95% bootstrap 0–4; p = 0.056). ESPB showed better visualization of local anesthetic spread and was significantly easier to perform. PACU duration, highest NRS score and total opioid dose, complications of the nerve block and patient satisfaction were comparable for the two groups. Conclusions Failure to demonstrate non-inferiority was possibly caused by under powering, suboptimal dosing and operator experience. Considering the significant simplicity and lower procedural risk of ESPB, ESPB may be practical alternative compared to PVB, especially in low PVB volume centers and should be considered for use in patients undergoing mastectomy combined with IBR. Clinical trial registration number NL75733.031.20