Origin, Branching, and Communications of the Intercostobrachial Nerve: a Meta-Analysis with Implications for Mastectomy and Axillary Lymph Node Dissection in Breast Cancer

The intercostobrachial nerve (ICBN), which usually originates from the lateral cutaneous branch of the second intercostal nerve, innervates areas of the axilla, lateral chest, and medial arm. It is at risk for injury during operative procedures that are often used in the management of breast cancer and such injury has been associated with postoperative sensory loss and neuropathic pain, decreasing the quality of life. PubMed, Excerpta Medica Database (EMBASE), ScienceDirect, Google Scholar, China National Knowledge Infrastructure (CNKI), Scientific Electronic Library Online (SciELO), Biosciences Information Service (BIOSIS), and Web of Science were searched comprehensively. Data concerning the prevalence, branching, origin and communications of the ICBN were extracted and pooled into a meta-analysis. A total of 16 studies (1,567 axillas) reported data indicating that the ICBN was present in 98.4% of person. It most often (90.6%) originated from fibers at the T2 spinal level and commonly coursed in two branching patterns: as a single trunk in 47.0% of cases and as a bifurcating pattern in 42.2%. In the latter cases, the bifurcation was usually unequal (63.4%). Additionally, the ICBN presented with anastomosing communication to the brachial plexus in 41.3% of cases. The ICBN is a prevalent and variable structure at significant risk for injury during operative procedures of the axilla. In view of the postoperative pain and paresthesia experienced by patients following injury, surgeons need to exercise caution and aim to preserve the ICBN when possible. Ultimately, careful dissection and knowledge of ICBN anatomy could allow postoperative complications to be reduced and patient's quality of life increased.