Continuous serratus–intercostal plane block versus intercostal cryoanalgesia for postoperative pain after minimally invasive cardiac surgery: a prospective comparative observational study

BACKGROUND: Minimally invasive cardiac surgery via minithoracotomy is associated with postoperative pain. Continuous BRILMA (block of the lateral branches of the intercostal nerves in the mid-axillary line) and intercostal cryoanalgesia are opioid-sparing techniques, but comparative evidence in this setting is limited. METHODS: In this prospective comparative observational study, consecutive adults undergoing minimally invasive cardiac surgery received either continuous BRILMA or intercostal cryoanalgesia according to routine institutional practice. Treatment allocation was not determined by the study protocol and no randomization was performed. Pain at rest and during deep inspiration was assessed using the Numerical Rating Scale (NRS) after extubation and at 24, 48, and 72 h, discharge, and 30 days. The primary endpoint was pain at rest over the first 72 h. Secondary outcomes included inspiratory pain, opioid consumption during the first 72 postoperative hours, neuropathic pain, pulmonary complications, and hospital stay. Longitudinal analyses were performed using linear mixed models adjusted for age, sex, and surgical time. RESULTS: Sixty-three patients were analyzed (BRILMA n = 33; cryoanalgesia n = 30). Pain decreased significantly over time in both groups (p < 0.001), with significant group-by-time interactions at rest (p = 0.002) and during deep inspiration (p < 0.001). BRILMA was associated with lower early pain scores, particularly at 72 h, whereas cryoanalgesia showed comparable or lower pain levels at 30 days. Although a greater proportion of patients in the cryoanalgesia group required rescue opioids, cumulative opioid exposure in the first 72 h was low in both groups. Neuropathic pain incidence was low and similar between techniques. CONCLUSION: BRILMA was associated with lower early postoperative pain scores, while cryoanalgesia showed a trend toward lower pain levels at 30 days. Overall opioid requirements and neuropathic pain rates were low, suggesting that both regional techniques may represent suitable regional analgesic strategies in this setting. TRIAL REGISTRATION: The study was prospectively registered at ClinicalTrials.gov (NCT06086535; October 17, 2023). Ethical approval was obtained from the Clinical Research Ethics Committee of Vall d'Hebron University Hospital (Barcelona, Spain) (protocol number: PR(AG)324/2022; approved on November 25, 2022).