CDA Essentials 2018 • Volume 5 • Issue 4

28 | 2018 | Issue 4 I ssues and P eople As a prosthodontic resident and a master’s student at the University of Toronto, Dr. Eszter Somogyi-Ganss participated in the creation and evaluation of a new navigational system that allows surgeons to connect a previous CT image to the patient’s anatomy in real time and then easily navigate the implants to the bone on the patient’s face. Designed for use in dentistry, the system is currently being modified and tweaked for use in other facial surgeries. Now a maxillofacial prosthodontist in Sunnybrook’s Craniofacial Prosthetics Unit in the Department of Dentistry, Dr. Somogyi-Ganss works with surgeons to examine CT images and plan where best to place the surgical screws. The team then loads up the plan into the navigation system and it guides their hands and drill to the right spot. “To place surgical implants, the surgeon may have to drill up or down or sideways,” she explains. “This computer-guided system tells the surgeon: ‘Drill here. Drill this deep. Drill on this angle.’” And it all happens in real time. “This system is like a glide path in an aircraft,” says Dr. Kevin Higgins, one of the head and neck surgeons at Sunnybrook who performed Brenda’s surgery. “You have your flight path, and if there’s any deviation, you get an alert. It tells you to stop. This surgical system guides exactly how you are holding the drill – the pitch, the yaw and the roll – so you get optimal placement. It’s taking precision placement to the next level.” Typically for surgeries like this, a pre- operative image is used to plan the screw placement, and a guide mask is made out of plastic and placed over the patient’s face. Surgeons then drill into the premade holes in the template, keeping an eye on the previously completed image. But imaging isn’t always 100 per cent accurate and the masks rely on being placed in the exact same spot. The masks also don’t allow the surgeons to make adjustments in the moment. “With the navigation system, if you’ve figured out that the bone isn’t good enough and you want to Dr. Kevin Higgins (r.) and Dr. Fred Laliberte (l.) use a new navigational system to help guide the placement of two 3-millimetre screws. Dr. Higgins (r.) uses the surgical navigational system, which maxillofacial prosthodontist Dr. Eszter Somogyi-Ganss (c.) helped to design. Photos courtesy of Kevin Van Paassen/Sunnybrook Health Sciences Centre.