An interactive augmented reality software for facial reconstructive surgeries

BACKGROUND AND OBJECTIVE

Surgical trainees need a lot of training and practice before being able to operate independently. The current approach of surgical education mainly involves didactic teaching and psychomotor training through physical models or real tissue. Due to the unavailability of physical resources and lack of objective ways of evaluation, there is a demand for developing alternative training methods for surgeons. In this paper, we present an application that provides additional training opportunities to surgical trainees in the field of facial reconstructive surgeries.

METHODS

We built a mobile augmented reality application that helps the user to visualize important concepts and experiment with different surgical plans for facial reconstructive surgeries. The application can overlay relaxed skin tension lines on a live video input or a patient's photo, which serve as bases for aligning a skin flap. A surgical trainee can interactively compare different skin flap design choices with estimated final scars on a photo of a patient. Data collection capability is also added to the application, and we performed a Monte Carlo experiment with simulated users (five classes of 100 users each) as an example of objectively measuring user performance.

RESULTS

The application can overlay relaxed skin tension lines on a patient's face in real time on a modern mobile device. Accurate overlays were achieved in over 91% as well as 84% and 88% out of 263 generated face images, depending on the method. Visual comparisons of the three overlay methods are presented on sample faces from different population groups. From the Monte Carlo experiment, we see that user actions in each class follow a normal distribution with a distinct set of parameters.

CONCLUSIONS

This application can serve as a basis for teaching surgical trainees the fundamentals of different facial reconstructive procedures, especially concepts related to relaxed skin tension lines and skin flaps. It can objectively evaluate the performance of surgical trainees in a course. This setup focuses on illustrating the relationship between the orientation of skin flaps and relaxed skin tension lines, which is a prerequisite of minimizing scarring in patients in addition to good surgical techniques.

[The thin ALT perforator flap for oropharyngeal robotic-assisted reconstruction]

Since a few years, the transoral robotic surgery reduced the morbidity of oropharyngeal tumors excision. Large posterior tumors can now be removed without any scar visible on the face. In this context and to respect the thinness required for reconstructions at the junction of the upper aerodigestive tract, the free radial forearm flap still remains the solution of choice. However, if the transoral robotic surgery respects the anatomy and the aesthetics of patients at the visible and social area that represents the face, the forearm flap provides visible scars on the other region of social interaction that represents the upper limb. The aim of our work was to prove the feasibility and the benefits in terms of reducing sequelae when using a thin anterolateral perforator flap harvested above the plane of the superficial fascia. We present this new original method in detail and the advantages it offers to patients after surgery.

[Harvesting technique of chimeric multiple paddles fibular flap for wide oromandibular defects]

Carcinological head and neck reconstruction still remains a challenge due to the volume and varied tissues needed. Large and wide oromandibular defects require, not just the bone but also soft tissues for the pelvilingual reconstruction and therefore, a second free flap may become necessary in addition to a fibular flap. The option of an unique chimeric flap based on the fibular artery and its branches is less known whereas it offers the advantage of a unique flap with bone, muscle and multiple skin paddles, independent of each other. The aim of this technical note is to present step by step the surgical procedure of this chimeric flap and share this method that avoids a second free flap.

[Submental island flap: a review of the literature]

The submental island flap is a precious tool in reconstructive surgery. It was described by Martin in 1993, inspired by platysma flaps. In our days, we can find many reliable techniques for this procedure. We reviewed the main studies of the literature that described a total of 528 patients. The rate of partial necrosis was 5.1%, complete necrosis 1.7%, and reversible lesions of the marginal mandibular branch of the facial nerve 1.1%. His versatility makes this flap appropriate for the reconstruction of every part of the face: cheeks, nose, forehead, moustache, beard, and hairs. It can also be used de-epidermised with very good results, for the reconstruction of the buccal cavity, the tongue, the roof of the mouth, the larynx, and the proximal part of the esophagus. The SMAP (Submentalis Artery Perforator flap) is an alternative flap that provides even better cosmetic results. The development of indocyanine green and infrared cameras will allow in a close future to decrease the postoperative complications.