Bone segment navigation

It uses for the first time natural registration surfaces instead of single artificial x-ray visible markers, in order to achieve a higher precision (1 mm and better).

An osteotomy is a surgical intervention that consists of cutting through bone and repositioning the resulting fragments in the correct anatomical place.

An alternate strategy is to plan the procedure entirely on a CT scan generated model and output the movement specifications purely numerically.

[7] The osteotomies performed in orthognathic surgery are classically planned on cast models of the tooth-bearing jaws, fixed in an articulator.

Since the 1990s, modern techniques of presurgical planning were developed – allowing the surgeon to plan and simulate the osteotomy in a virtual environment, based on a preoperative CT or MRI; this procedure reduces the costs and the duration of creating, positioning, cutting, repositioning and refixing the cast models for each patient.

The usefulness of the preoperative planning, no matter how accurate, depends on the accuracy of the reproduction of the simulated osteotomy in the surgical field.

More recently a similar system, the Surgical Segment Navigator (SSN), was developed in 1997 at the University of Regensburg, Germany, with the support of the Carl Zeiss Company.