The ideal intercostal space for internal mammary vessel exposure during total rib-sparing microvascular breast...

Total rib-preserving free flap breast reconstruction (RP-FFBR) using internal mammary vessel (IMV) recipients usually involves vessel exposure in the second or third intercostal spaces (ICS). Although the third one is more commonly used, no direct comparisons between the two have hitherto been performed.

To compare the in-vivo topography and vascular anatomy of second and third ICSs in patients undergoing FFBR using the rib-preservation technique of IMV exposure.

An analysis of prospectively collected data on intercostal space distance (ISD), number and arrangement of IMVs, location of venous confluence, and vessel exposure time was conducted on a single surgeon's consecutive RP-FFBRs.

A total of 296 RP-FFBRs were performed in 246 consecutive patients. The second, third, or both second and third spaces were utilized in 282, 28, and 22 cases, respectively. The ISDs were 20.6 mm ± 3.52 for the second ICS and 14.0 mm ± 4.35 for the third ICS (p<0.0001, CI = 5.17-7.97, t-test). The second versus third ICS vein content was as follows: single 81.4% vs. 74%, dual 18.6% vs. 26%, and confluence 3.7% vs. 13%. The second ICS single vein was medial to the artery in 92.6%. The third ICS single vein was medial to the artery in 88.2% Vessel exposure times for second (47.2 mins ± 26.7) and third (46.5 mins ± 31.4) spaces were similar (p = 0.93). The overall intraoperative anastomotic revision rate was 9.1%, and the postoperative flap re-exploration rate was 4.0%, with 99.7% overall flap success.

Preferential use of the second ICS is supported by its more predictable vascular anatomy, a broader space for performing the microanastomoses and a higher frequency of a single postconfluence (and thus larger) vein facilitating the microsurgery.