Comparison between ultrasound-guided subpectoral intercostal plane approach and pectoserratus plane approach for intercostobrachial nerve block in surgeries involving posterior and medial aspects of the arm - A randomised comparative trial.

Background and aims: The intercostobrachial nerve (ICBN), along with the brachial plexus, supplies the medial and posterior aspects of the upper arm. This study hypothesised that ultrasound blockade of ICBN by subpectoral intercostal plane block may provide faster and complete blockade compared to the pectoserratus plane block.

Methods: Sixty patients were randomised into two groups, and initially, an ultrasound-guided supraclavicular brachial plexus block was performed. After 10 min, Group A received a subpectoral intercostal plane block at the second rib. Group B received a pectoserratus plane block at the fourth rib. Anaesthesia over the posterior and medial aspects of the upper arm was assessed. The primary outcome was the time of onset of the blockade. The secondary outcome was the time taken to perform the block and the block failure rate. Student's t-test was used to compare the means. The categorical variables were compared using the Chi-squared test. Significance was defined by a P value of <0.05.

Results: The time of onset of the block over the medial and posterior sides of the arm was significantly faster in Group A. Time taken for administering block in Group B was more than twice that of Group A (P < 0.001). The block was 100% successful in Group A, while in Group B, only 70% was successful.

Conclusion: The subpectoral intercostal plane block at the second rib produces a faster and more complete blockade of ICBN in all patients compared to the pectoserratus plane block at the fourth rib.