Augmented Reality in Breast Reconstructive Surgery - Projecting Pre-operative DIEP Flap Planning onto Patients in a Randomized Controlled Trial

In Deep Inferior Epigastric Artery Perforator (DIEP) flap breast reconstructions, the survival of this free flap relies on perforators, providing blood supply to the newly molded breast. Preoperative mapping of these randomly distributed blood vessels is of the essence to avoid complications. Depicting these perforators can be achieved through Computed Tomography Angiography (CTA), on which a virtual DIEP flap pre-operative planning can be created by post-processing techniques. Through means of a newly developed innovative hand-held projection device, this planning can be projected directly onto the patient's abdomen, ensuring a stabilized and aligned representation of the surgical planning regardless of movement of the patient or projection system. In this clinical trial, it was investigated whether the pre-operative projection of a virtual planning directly onto the patient's abdomen leads to more correctly identified perforator locations and less operation time spent on dissecting the free flap compared to the commonly used handheld Doppler ultrasound method.

The study design was a, open, single-center randomized controlled trial in patients undergoing a DIEP flap breast reconstruction between December 2015 to March 2017 with 1 week follow-up. The participants (n=60) undergoing a DIEP flap breast reconstruction without a lymph node transfer were randomly allocated in either the projection group (n=33, age 52 ± 9 yrs, BMI 26.5 ± 2.0), or the control group (n=27, age 50 ± 8 yrs, BMI 26.8 ± 2.7). In the projection group a virtual 3D planning was created, projected and traced onto the patients' abdomen prior to surgery using the newly developed projection device, where in the control group the perforators were located using handheld Doppler ultrasound.

In total, sixty patients provided 69 DIEP flaps for analysis. The projection method is convenient in practice and capable preoperatively of displaying significantly more perforators compared to the Doppler method (respectively 61.7% ± 7.3% versus 41.2 ± 8.2%, p=0.020) and decreasing flap harvest time by 19 minutes (136 ± 7 versus 155 ± 7 minutes, p=0.012). Complications were comparable across both groups.

Not only can more perforators be identified intraoperatively using the projection method compared to handheld Doppler ultrasound, but there is also a significant time reduction in harvesting the DIEP flap without increasing complications.