Journal Article

EP171 Anatomical and gravitational effects on injectate distribution in thoracic paravertebral block in the lateral position: a pilot cadaveric study

Nitta Asako, Ohsaki Yuki, Sawada Atsushi, Yamakage Michiaki, Kumita Sho

2025

Overview

Background and AimsThis pilot cadaveric study aimed to evaluate the role of anatomical asymmetry in the thoracic paravertebral space (TPVS) and gravitational forces on dye-spread during bilateral TPVB performed in the lateral position.MethodsThe study was approved by the Ethics Committee of Sapporo Medical University between January 2022 and August 2024 (Nos. 3–1–61, 4–1–49, and 6–1–39). Twelve soft-embalmed Thiel cadavers were used: six were placed in the left-lateral position and six in the right-lateral position. A single-injection of 20 mL dye was administered to each TPVS using an ultrasound-guided intercostal approach. After 20 min, the cadavers were repositioned in a supine position. The vertebral segmental numbers of stained TPVSs and intercostal spaces (ICSs) were recorded.ResultsTPVB performed on the left side demonstrated significantly more stained segments (median [interquartile range]) than that performed on the right side (TPVS: 4.0 [3.0–5.0] vs. 2.0 [1.0–3.0], p = 0.01; ICS: 4.0 [3.0–5.0] vs. 3.0 [2.0–4.0], p = 0.04). However, no significant differences in dye-spread were observed between the upper and lower sides (TPVS: 4.0 [1.0–5.0] vs. 2.0 [2.0–5.0], p = 0.63; ICS: 4.0 [2.0–4.0] vs. 3.0 [2.0–5.0], p = 0.69).ConclusionsWe demonstrated that the larger volume of the left TPVS compared with the right TPVS may contribute to a more extensive spread, whereas gravitational forces appear to be minimal. Our findings suggest that a larger volume of local anesthetic may be required on the right side to achieve analgesia comparable to that on the left side.

• Publisher: BMJ Publishing Group LTD
• Subject: Cadavers