Single- versus Multiple-Injection Intertransverse Process Block for VATS: A Randomized Trial on Dermatomal Sensory Blockade

While the intertransverse process (ITP) block can enhance chest wall analgesia, the optimal injection technique remains unclear. This study compared the efficacy of single versus multiple injections of the ITP block, hypothesizing that multiple injections would provide superior sensory blockade. Forty patients undergoing video-assisted thoracic surgery were randomized to receive single or multiple ultrasound-guided ITP block injections with 30 mL of 0.25% bupivacaine and 1% lidocaine with epinephrine (5 μg/mL). The single-injection group received 30 mL at the T4-5 level, while the multiple-injection group received 10 mL/injection at the T3-4, T4-5, and T5-6 levels. The primary outcome was dermatomal sensory changes on the anterolateral chest wall. Secondary outcomes included block performance time, complications, and postoperative analgesia. The median (interquartile range [IQR]) dermatomal sensory levels were 2 (2-4) for single-injection and 3 (1.5-3.5) for multiple-injection (median difference: 0, 95% confidence interval [CI]: -1 to 1, p = 0.91). The single-injection group had a shorter median (IQR) block performance time than the multiple-injection group [7 (5.2-8.4) min versus 9.1 (7.8-11.2) min; median difference: -1.9 min; 95% CI: -4 to -0.1 min; p = 0.01]. Intraoperative hypotension occurred in 63.2% of the single-injection group and 65% of the multiple-injection group (p = 0.91). There was no statistically significant difference in postoperative pain intensity between groups. Single- and multiple-injection ITP blocks showed no significant difference in sensory changes or analgesic effect. The shorter performance time of the single-injection technique suggests it may be a more practical option. However, larger, higher powered studies are required to confirm equivalence and establish definitive recommendations.