Intercostobrachial nerve block – A painful puzzle decoded

Dear Editor, We appreciate the authors’ comments[1] on our published manuscript.[2] Pectoralis minor (PmM) arises from the third to fifth ribs and travels upwards to attach to the coracoid process. As we performed the block with the arm kept by the side, the probe tilted slightly medially in a parasagittal oblique direction, and we could see PmM in all cases. Initially, we also had the same doubt about the rib targeted. Radiological image confirmed it as the second rib [Figure 1]. Our method is distinct, aiming at the lower border of the second rib just medial to the axillary vein and not focused on any plane. However, the infraclavicular approach aims at the brachial plexus, and the point of injection is relatively superficial and cranial. In addition, in infraclavicular block, the drug is injected inside the axillary sheath, which limits the lateral spread of the drug to block the intercostobrachial nerve (ICBN). In our experience, the infraclavicular approach consistently blocks the ICBN.Figure 1: Radiological image showing probe placement and needle targeting second rib in the subpectoral intercostal plane approach for blocking the intercostobrachial nerveIn the study by Chen et al.[3] local anaesthetic is deposited in the costoclavicular–serratus anterior muscle space. Only three cases were studied without statistical analysis. Acute pain relief was studied, not the surgical anaesthesia. The blockade of ICBN territory has not been explored. Visualising the structures may not be easy, especially in obese patients. Many studies have used a local anaesthetic mixture, with a dosage similar to ours without any reported toxicity.[4] In our study involving 60 patients, no local anaesthetic toxicity was observed. Previous studies by Samerchua et al. and Moustafa and Kandeel used low drug volume with a low success rate.[5,6] Hence, we used 15 mL. In summary, the technique we follow is simple and produces consistent results when compared to other methods. Author contributions SK, BSV: Concept, design, definition of intellectual content, experimental studies, data acquisition, data analysis and statistical analysis. SK, BSV, MC: Literature search, manuscript preparation, editing and review. Disclosure of use of artificial intelligence (AI)-assistive or generative tools The AI tools or language models (LLM) have not been utilised in the manuscript, except that software has been used for grammar corrections and references. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.