Near-infrared spectroscopy for monitoring tissue oxygenation in breast reconstruction

Background : A breast reconstruction with a deep inferior epigastric artery perforator flap (DIEP-flap) is commonly performed microvasculared procedure. It is crucial to detect vascular complications as early as possible to maximize the chance on a successful flap revision. Near-infrared spectroscopy (NIRS) measures the tissue oxygen saturation (StO2), by using infrared light and can be an interesting tool to monitor flap perfusion. Objective : The aim of this study is to determine whether NIRS is suitable to assess tissue perfusion after DIEP-flap reconstruction. Methods : The trial was designed as a single cohort interventional pilot study (approved by the Ethics Committee of the University Hospital of Antwerp Internal reference number : 18/12/173 ; Belgian registration number : B300201836129). All patients scheduled for uni- or bilateral breast reconstruction by means of a DIEP-flap were included, if no exclusion criteria were present. The StO(2) was measured during the first 12 hours postoperatively. The StO(2) measurements were performed using a sensor positioned on the free flap and one on the native tissue. Results : Twelve women underwent a uni- or bilateral DIEP-flap breast reconstruction. In this study, the mean StO(2) values of the flap and of the native tissue were 90.16 +/- 4.63 % (mean +/- SD) and 91.52 +/- 2.23 % (mean +/- SD), respectively. The mean difference in StO(2) measurements between the free flap and the native tissue was 1.36 +/- 3.46 % (mean +/- SD). This difference was not statistically significant, according to the Wilcoxon signed-ranks test. In one patient, the StO(2) value of the free flap tissue had fallen to 52%, due to a hematoma. The patient underwent a successful re-exploration of the free flap. Conclusion : Our data showed that NIRS is an easy, tissue-specific, objective and sensitive way to monitor tissue oxygenation in a continuous manner, after free flap breast reconstructions.