Intercostal nerve block of the anterior cutaneous branches and the sensibility of the female breast

Abstract

Introduction: Better sensation in the reconstructed breast improves the quality of life. Sensory nerve coaptation is a valuable addition to autologous breast reconstruction. There are few publications concerning the sensory nerves of the breast and the nipple-areola complex and reports are contradictory, so it is unknown which nerve is best suited as a recipient for coaptation. The current study serves as a proof of concept.

Materials and methods: The areas innervated by the anterior cutaneous branches (ACBs) of the intercostal nerves (ICNs) were studied on two separate occasions in two healthy women. First, the ACBs of ICNs 2-5 were individually blocked using ultrasound. Next, the ACBs of all levels were blocked simultaneously. Sensation was measured using Semmes-Weinstein monofilaments. The numbed areas corresponding to the ICNs were drawn in a raster of 2 × 2 cm.

Results: The largest area was supplied by the ACB of the 4th ICN, located in the upper (UIQ) and the lower (LIQ) inner quadrants of the breast. The 2nd-largest area was supplied by the ACB of the 3rd ICN. Blockage of ACBs 2-5 affected sensation in the nipple and the areola.

Conclusions: Blockage of all levels 2-5 partially affected sensation in the nipple-areola complex, suggesting innervation by a nerve plexus consisting of both ACBs and lateral cutaneous branches (LCBs). ACB4 supplied the largest area of the breast in the UIQ and LIQ and could be best suited for sensory nerve coaptation to optimize sensation in the autologously reconstructed breast.

Keywords: breast cancer; breast reconstruction; intercostal nerve; nipple-areola complex; sensation.

Figure 1

A schematic illustration of the anatomy of the intercostal arteries, veins, and nerves. (1) Lateral cutaneous branches (LCBs) of the intercostal nerve (ICN); (2) Neurovascular bundle running in the intercostal groove (consisting of the intercostal vein, artery and nerve from cranial to caudal); (3) External intercostal muscles; (4) Internal intercostal muscles; (5) Innermost intercostal muscles (imm); (6) Anterior cutaneous branches (ACBs) of the intercostal nerve (ICN)

Figure 2

Schematic overview of the setup. Lateral view from the left side of the participant; injection of lidocaine for sonographically‐guided nerve block of the anterior cutaneous branch (ACB) of an intercostal nerve (ICN) of the right breast. The probe was moved from cephaled to caudad to identify the targeted intercostal space. Once this was identified, the probe was only rotated from medial to lateral without replacement [Color figure can be viewed at wileyonlinelibrary.com]

Figure 3

Ultrasound image of the intercostal plane block of the anterior cutaneous branch (ACB) of the third intercostal nerve (ICN) on the left side. Local anesthetic spread (*) between the internal intercostal muscle (IIM) and the innermost intercostal muscle (imm). White arrow: needle. PM, pectoralis major muscle; SC, subcutis; EIM, external intercostal muscle. C3: 3rd rib. C4: 4th rib [Color figure can be viewed at wileyonlinelibrary.com]

Figure 4

The areas corresponding to the 2nd to 5th ICNs, measured in participant 1. The first measurements (M1) show the areas supplied by the 2nd, 3rd, and 5th ICNs. The second measurements (M2) show the areas supplied by the 4th ICN and all levels together [Color figure can be viewed at wileyonlinelibrary.com]

Figure 5

Drawings of the photos of the areas supplied by the 2nd to 5th ICNs, measured in participant 2. The first measurements (M1) show the areas supplied by the 2nd, 3rd, and 5th ICNs. The second measurements (M2) show the areas supplied by the 4th ICN and all levels together [Color figure can be viewed at wileyonlinelibrary.com]