Virtual Surgical Tools for Planning Craniofacial Surgery
KEVIN MONTGOMERY PhD, Michael Stephanides MD, Stephen Schendel MD, Muriel Ross PhD
National
Biocomputation Center
Stanford University/NASA
Ames Research Center
Division of Plastic
and Reconstructive Surgery
900 Welch Road, Suite
15
Palo Alto, CA 94304
Phone: 650 4986978
Fax: 650 7251449
Email: kevin@biocomp.stanford.edu
BACKGROUND____________
Craniofacial surgeons use CT and MRI images to plan their surgery for a variety of craniofacial deformities. The process of surgicalplanning is based on visual inspection of these images and thepatient exam. A system that would enable the surgeon to performvarious osteotomies, measurements, manipulations of bony fragmentsand visualization of the results in a virtual environment priorto surgery would allow for customized surgeries, optimal resultsand reduced operating time. In addition, such a tool would bebeneficial for teaching unusual and difficult procedures thatare encountered only at major referral centers.
PURPOSE_________________
The development of a computerized surgery planningsystem that incorporates available patient data into a realistic3-dimensional virtual environment.
METHODS________________
Custom software was developed, to transform patientCT and MRI data into high quality 3 Dimensional images of bonesand soft tissues. These images were incorporated into a virtualenvironment consisting of a custom made 3D display technology,consisting of a high end CRT Sony projector and a back-projectionscreen. A user wearing tracked shutter glasses is able to view3-D models that appear as realistic objects floating in frontof the screen. Interaction with the images is accomplished usinga dataglove, enabling natural hand gestures to be used for themanipulation of virtual objects. A selection of surgical instrumentswas digitized using a 3D laser scanner. The surgeon is able tointeract with this 3-D environment for preoperative planning aswell as teaching. Application of soft tissue modeling techniquesallows the soft tissues to conform to the underlying bony changes.
RESULTS________________
We were able to develop 3-dimensional high qualitysoft tissue and bony images from existing CT scans. A virtualreality surgical environment was also developed, allowing thesurgeon to use these images in order to better understand theproblem and "practice" the proposed procedure. Thissystem has been applied for a group of select patients with difficultcongenital malformations. With further development we anticipatethe use of this system routinely for most of the patients.
