22 years ago, a local technical college had acquired a printer system based on laser solidification of epoxy fluid to produce a 3D model layer by layer. The MRI data was from a patient of mine at Oulu University Hospital. The patient had been operated for third ventricluar cyst in an open procedure years before.
The pioneering navigational software of Onesys Oy was used to segment the scalp and ventricular system and the printer made a life-sized model. The new procedure was practiced by drilling a navigated hole into the model for precise placement of the endoscope introducer. This software solution helped pave the way for developing an imaging solution for clinicians and surgeons, not only radiologists.
Successful removal of the cyst was done with a Codman endoscope guided into position using the Onesys Navigator software, which featured the TCS (tool-coordinated system) now used in all image-guided systems of the various vendors. In the image, the TCS shows the yellow axis of the endoscope approaching the cyst.
The TCS images show where the endocope would be, and later was, going. TCS was revolutionary at a time when stereotactic orthogonal images were being used in other pioneering navigators. The seminal scientific paper on the TCS, originally called the "principle of the common axis" for surgical instruments including the endoscope and microscope was published in 1993, as recounted in earlier posts.
Reference:
Koivukangas J, Y Louhisalmi, J Alakuijala, J Oikarinen (1993) Ultrasound-controlled neuronavigator-guided brain surgery. J Neurosurg 79: 36-42.