HoloDIEP: Accurate Intraoperative DIEA Perforator Mapping Using a Novel Mixed Reality Tool

Introduction: Autologous free abdominal tissue transfer is the gold standard in postmastectomy breast reconstruction, but poses the challenge of technical complexity, due to variable vascular/perforator anatomy. Preoperative imaging, including computed tomography angiography (CTA) has mitigated this challenge; yet requires extrapolation of complex 3D topography from 2D images, and may not be intuitive. The fidelity of mixed-reality perforator maps has been demonstrated but has not been studied intraoperatively. Here, we compare the accuracy of the “HoloDIEP” in identifying perforator location (vs. Doppler ultrasound) by using holographic 3D-models derived from preoperative CTA.

Methods:  Using a custom application on HoloLens on 15 patients undergoing breast reconstruction, a 3D-projection is superimposed onto patient anatomy in the OR. Vascular points in the skin-markings are compared against the 3D-model in a coordinate system around the umbilicus. Holographic skin-markings and Doppler-identified markings were analyzed with a perspective-corrected photo technique against the 3D-model and intraoperative durations of both techniques are compared.

Results: Vascular points using HoloDIEP are -0.97 ± 6.2mm (perforators: -0.62 ± 6.13mm) away from the 3D-model ground-truth from the umbilicus at a true distance of 10.81 ± 6.14mm (perforators: 11.40 ± 6.15mm). Absolute difference in radial length is twice as high for Doppler identified markings (9.71 ± 6.16mm and 4.02 ± 3.20mm respectively). Only in half of all cases (7/14) more than 50% of the Doppler-identified points were reasonably close to 3D-model ground-truth.

Conclusion: Mixed Reality-enabled intraoperative perforator mapping with the HoloDIEP tool, provides millimeter accuracy and is faster and more accurate than Doppler.