Image Guided Surgery Video Series, Episode 5 - 3D Printed Models in Orthopedics

Dr. Johnson used a laser guide for approximately 15 years or more that allowed path selection on CT scan, but required motoring the patient backwards and forwards outside the gantry.

CT fluoroscopy allowed foot-pedal activated imaging but had disadvantages of static views, massive radiation to hands, and working in a gantry narrower than some drills and screws.

The hybrid operating room provides a fully sterile environment equivalent to where you could do a liver transplant, with a 3D CT scanner that shows drill and biopsy device position in real time during procedures.

The patient had relapsed Ewing sarcoma treated initially with radiation and chemotherapy, with tumor recurrence despite radiation.

Traditional pelvic tumor resection method involved using MRI and bony landmarks to make measurements with a ruler, feeling for soft tissue mass, making generous cuts, then performing reconstruction.

The manufacturer can also create a custom metal implant designed to fit the specific defect created by the planned resection.

Intraoperative CT scan is performed after soft tissue exposure to fuse with pre-operative MRI, with the patient in decubitus position.

Soft tissue exposure is performed before CT acquisition because significant motion can occur during exposure that would compromise image guidance accuracy.

Patient motion of even a few millimeters after CT scan acquisition causes errors because the scan cannot track where the patient has moved.

The pelvis is more rigid and doesn't tend to move as much as other body areas like the chest, making patient immobilization somewhat easier.

The scanner has navigational capabilities allowing planning of target points and entry points, which was used to guide pin placement at the sciatic notch as a starting point for cuts.

Post-resection CT while the patient is still on the table is particularly helpful for verifying screw placement, especially around the sacrum.

The hybrid OR enables pre-operative imaging, image fusion, navigational capabilities, intraoperative checkup, and post-operative verification, with some procedures that couldn't be done safely before and increased confidence in hardware placement.

Dr. Soldier views the hybrid OR technology primarily as backup because CT-manufactured cutting guides have become highly accurate.

The next technological advance involves antenna systems that can be placed on bone to eliminate concerns about patient motion and improve accuracy.