Real-Time Dynamic Navigation System for the Precise Quad-Zygomatic Implant Placement in a Patient with a Severely Atrophic Maxilla

Using real-time navigation surgery, we can treat patients with a severely atrophic maxilla requiring immediate implant loading, quickly, accurately and safely. A main advantage of this technique is that it improved the precision of this zygomatic implant placement, which is critical to its clinical use and safety. This technique allows treating of patients with severely atrophic maxilla due to ectodermal dysplasia, tumor, or severe periodontitis.

With the anesthetized patient lying on the operating table in the supine position, rigidly secure the skull reference base to the calvaria, with a single self-tapping titanium screw of 1.5 by 6 millimeters. Secure the reference array to the base and assemble it with three marked reflective spheres. Place the navigation system camera in the one o'clock position, to monitor the skull reference.

For registration, specifically set the navigation system to the individual patient using a positioning probe with a tailor-made reflective ball to contact the outer surface of the mini screws one after another. Then display the available sagittal coronal axial and 3D reconstruction images on the navigation screen. To standardize the drilling before using it in the surgery, use a calibration block with holes of different diameters.

The drills should be straightly attached to the bottom of the block by the surgeon, and then the assistant needs to adjust the interface into the calibration module. The equipment will produce a sound once the process is complete. After determining the extent of the incision using surgical navigation, lift the full thickness flap, allowing an adequate view for exposing the planned implant sites.

The range of the periosteal elevation should contain the alveola crest, lateral wall of the maxilla and the inferior border of the zygomatic bone. With the help of the navigation probe, find the entry point and use the zygoma handpiece to fix the entry points. Then find the entry of the zygomatic bone with the probe and use the zygoma handpiece to prepare the entry point of the zygomatic bone.

Next, perform the drilling procedure ensuring that it follows the trajectories from the entry to the exit point as planned. Used the 2.9 millimeter drill first to prepare the path from the entry point, which was located using the navigation probe to the entry of the zygomatic bone. Prepare the mesial one first, followed by the distal one.

To widen the implant bed, use the handpiece and extend the path from the entrance of the zygomatic bone to the terminal point designed at the surface of the zygomatic bone. Ask the assistant to put a hand on the surface of the lateral orbital wall, to ensure its safety. Next, enlarge the trajectory with an expanding drill with a 3.5 millimeter diameter.

Use the measuring bar and navigation probe to check the direction and position of the trajectory. Identify the length of the implant, using the measuring tool. If the depth does not meet the requirement of the planned length, prepare it to the set depth.

Next, implant the zygomatic implants using a specific manual tool then use the navigation probe to verify correct positioning. After placing multi-unit abutments and healing caps on the implants, suture the incision with the polypropylene 4-0 suture. For image integration, obtain post-operative CBCT scanning images and a panoramic radiograph to evaluate the zygomatic implant position within 72 hours after surgery.

Export the postoperative data to the planning software to superimpose the image of the post-operative CBCT and the pre-operative surgical plan. Comparing the location of the entrance point, endpoint, and angular deviation. After surgery, using the navigation system, the patient received a temporary restoration within three days, which addressed both the aesthetic and pronunciation issues.

Post-operative CBCT scanning and image integration revealed the starting and terminal position errors, as well as the angular deviation. Please check the position with the probe to ensure that the drilling is correct. We can also use our special manual tool to measure the distance from the starting point to the target point.

This protocol encourage researchers to explore the field further. The more and more research teams are trying to develop new navigation systems for maxilla facial and dental implant surgeries to increase accuracy and efficiency, as well as shorten the learning curve.