Efficacy of internal intercostal membrane-origin block versus thoracic paravertebral block for postoperative analgesia after video-assisted thoracoscopic surgery: a randomized controlled trial

Abstract Background This study aims to compare the internal intercostal membrane-origin block (IIMOB) with the thoracic paravertebral block (TPVB), analyzing the postoperative analgesic efficacy and safety in patients undergoing video-assisted thoracoscopic surgery (VATS). Methods A total of 236 patients were enrolled. Patients undergoing uniport VATS were randomized to uniport TPVB (UP) or uniport IIMOB (UI) ( n = 54 each), and those undergoing multiport VATS were randomized to multiport TPVB (MP) or multiport IIMOB (MI) ( n = 54 each). Postoperatively, patients in UP and MP groups received TPVB, while those in UI and MI groups received IIMOB. Additional VATS patients were randomly divided into two groups ( n = 10 each), methylene blue TPVB (BP) and methylene blue IIMOB (BI) groups, to assess injectate spread. The primary outcome was postoperative analgesic efficacy, quantified as the area under the curve (AUC) of Numerical Rating Scale (NRS) scores at rest and during coughing from 3 to 48 h after surgery. Results Compared with TPVB, IIMOB was associated with lower postoperative NRS-AUC values at rest and during coughing (all P < 0.05), reduced sufentanil consumption within 48 h, delayed first pump use, and smaller increases in plasma levels of perioperative inflammatory and neuroendocrine stress biomarkers at 24 h post operation. Additionally, patients received IIMOB experienced fewer incidences of back pain, hypotension, vascular injury, and block failure. There was no significant difference in the methylene blue diffusion gaps between the BI and BP groups. However, the BP group had a larger blue-dyed area in the ventral region of spinal column and higher 90-min dye color change rate compared with the BI group. Conclusion These findings revealed that IIMOB provided superior analgesia with fewer adverse events than TPVB after VATS. Clinical trial registration Chinese Clinical Trial Registry, ChiCTR2400082500. Registered on 29 March 2024, http://www.chictr.org.cn/ChiCTR2400082500 .