A Comparison of the Analgesic Efficacy of Serratus Anterior Plane Block Vs Paravertebral Nerve Block for Video-assisted Thoracic Surgery: a Randomized Controlled Trial

Background: Patients who undergo video-assisted thoracic surgery (VATS) that impair the integrity of the chest wall frequently experience moderate to severe postoperative pain. Serratus anterior plane block (SAPB) is a relatively novel technique that can block the lateral cutaneous branches of the intercostal nerves as well as the long thoracic nerve. Methods: Our study aimed to evaluate the analgesic efficiency of deep serratus plane block (DSPB) and superficial serratus anterior plane block (SSPB) as well as paravertebral nerve block (PVB) in the patients undergoing VATS. A total of 74 patients aged from 20-80 undergoing VATS were randomized to receive either DSPB or SSPB as well as PVB. Ultrasound (US) guided DSPB or SSPB as well as PVB with 20ml 0.5% ropivacaine was performed preoperatively to the patients according to their groups. All patients were provided with patient-controlled intravenous analgesia (PCIA) for postoperative analgesia. The primary outcomes were the levels of postoperative pain at rest and on coughing evaluated by visual analog scale (VAS), intraoperative and postoperative opioids consumption. The secondary outcomes included PCIA pressed times, side effects and satisfaction of analgesia, duration of nerve block, intraoperative hemodynamic changes and vasoactive drug dosage. Results: No significant differences of VAS score were found in the three groups at each time points. During operation, PVB reduced consumption of opioids (27.23±5.10mg) compared to DSPB (31.20±3.80mg) and SSPB (32.61±5.28mg) (p<0.05). The effective pressed times of PCIA in SSPB group (0.18±0.65) was significantly lower compared to PVB group (1.09±1.50) (p=0.009) at postoperative 12h. Accordingly, SSPB group reduced the dosage of PCIA (26.55±4.72ml) than PVB group (31.45±7.60ml) (p=0.046). Time consuming of PVB procedure was longer (11.14±1.66min) than DSPB (5.68±1.10min) and SSPB (4.77±1.04min) (p<0.001, respectively). PVB group was associated with more intraoperative atropine consumption (0.14±0.24mg) than DSPB group (0mg) (P=0.043). Conclusion: DSPB and SSPB are easy to perform and can serve as a promising alternative technique to PVB that may offer comparable analgesic effectiveness and a better side-effect profile for patients who undergoing VATS. Trial registration: This study was registered to Chinese Clinical Trials Registry on July 20, 2019. (Registration No: ChiCTR1900024678)