Helping Surgeons Sculpt

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Researchers develop a virtual navigation tool to guide reconstructive surgery of the jaw.
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In addition to removing tumours, reconstructive jaw surgery is often used to fix bone deformities or repair the jaw after an injury.
The French artist Auguste Rodin is most known for his sculptures of the human body. Through intense study of the contours and shapes of body parts, Rodin produced works that are considered among the most life-like and realistic sculptures ever created.

Surgeons, like sculptors, require a deep, three-dimensional understanding of the human body and its structure—especially reconstructive surgeons, who perform complex procedures to restore the shape and function of body parts. Unlike sculptors, however, surgeons are not afforded with the luxury of starting over. For example, the surgical removal of tumours in the head and neck region may require cutting the jawbone; if this is not performed precisely, it can have a significant impact on the patient’s ability to talk, breathe or swallow.

To help surgeons perform precise bone cuts during jaw surgery, a team of researchers led by Drs. Jonathan Irish (Director of Clinical Research Faculty and Core Lead of the Guided Therapeutics Program, Techna) and John de Almeida (Affiliated Faculty, Techna) developed a virtual navigation system. The system uses multiple images of a patient’s jaw to recreate a three-dimensional virtual model of the jaw—enabling surgeons to map out where they want to cut and to follow their progress on a display system in real time as they perform the procedure.

The research team enlisted four experienced surgeons to help evaluate the system. Each surgeon performed a series of mock procedures using either the virtual navigation system or the traditional method, which involves fabricating a physical guide that is applied directly to the patient’s jaw. After analyzing over 400 mock procedures, the team found that the virtual guide enabled the surgeons to cut jawbones with greater accuracy than the physical guide: approximately 99 per cent of the procedures were within five millimeters of targets.

"Our new system is less costly than traditional methods and takes less time to adjust should changes be required before the procedure," says Dr. Irish. "Our next step will be to evaluate the incorporation of this virtual guiding system into the surgery process."

This work was supported by the Strobele Family GTx Research Fund, the Kevin and Sandra Sullivan Chair in Surgical Oncology, the Hatch Engineering Fellowship Fund, the RACH Fund and The Princess Margaret Cancer Foundation.

Bernstein JM, Daly MJ, Chan H, Qiu J, Goldstein D, Muhanna N, de Almeida JR, Irish JC. Accuracy and reproducibility of virtual cutting guides and 3D-navigation for osteotomies of the mandible and maxilla. PLoS One. 2017 Mar 1. doi: 10.1371/journal.pone.0173111.