Analgesic efficacy of the subtransverse process interligamentary plane block in thoracic surgery: A randomized,...

Clinical evidence on the analgesic efficacy of the subtransverse process interligamentary plane (STIL) block after thoracic surgery remains limited. This study aimed to compare the postoperative analgesic efficacy of the STIL block versus the thoracic paravertebral block (TPVB) in thoracic surgery.

This randomized, non-inferiority trial enrolled patients undergoing video-assisted thoracoscopic surgery at a large academic medical center in China. Patients were randomly assigned (1:1) to receive either the STIL block or TPVB. Both groups received a single-shot injection of 15 mL of 1% ropivacaine mixed with 2% lidocaine. The primary outcome was pain intensity during deep inspiration within 48 h postoperatively, assessed by the area under the curve (AUC) of the numeric rating scale. A non-inferiority margin of 34 was predefined, and analyses were performed in both intention-to-treat and per-protocol populations.

From February 1, 2023, to December 30, 2024, 114 eligible patients (median age 58 years [IQR 49-61]; 54.0% female) were enrolled and randomly assigned to receive either the STIL block (n = 57) or the TPVB (n = 57). Nine patients were excluded after randomisation, resulting in 105 patients included in the per-protocol analysis. In the per-protocol population, the 48-h postoperative pain AUC during deep inspiration was 196.04 ± 2.50 for the STIL group and 187.49 ± 4.13 for the TPVB group (mean difference = 8.59; 95% CI, -0.94 to 18.14). In the intention-to-treat population, the values were 195.24 ± 2.49 and 186.44 ± 4.03, respectively (mean difference = 9.12; 95% CI, -0.39 to 18.63), both within the predefined noninferiority margin. No serious adverse events were observed in either group.

This randomized clinical trial demonstrates that, in the studied population, the subtransverse process interligamentary plane block was non-inferior to the thoracic paravertebral block for postoperative pain control after thoracic surgery, providing an effective alternative for analgesia.