Can the placement of nasal implants for prostheses be improved by a 3D bone thickness map?

Background:

Implants of the epiplating system (Medicon eG Tuttlingen) are usually placed intuitively based on intraoperative judgement of the bone. Would knowledge of bone thickness allow for insertion in areas with higher bone stock in the paranasal region?

Material and Methods:

We analyzed pre- as well as postoperative CT scans of 20 patients receiving implants

for nasal prostheses at the ENT Department of University Hospital Heidelberg from January 2005 through June 2017. DICOM data were imported into Amira (Thermo Fisher Scientific), and a color coded 3D bone thickness map was segmented. Implants were virtually moved in the 3D data set into a position with higher bone thickness. The difference in position was evaluated by aid of a score, and the length of the vector was measured.

Results:

The mean bone thickness was 1.78 mm (± 1.43). In 11 cases (46%), a relevant change was achieved (score > 1.5 points). On the whole group as well as the subgroup of Y-plates, the difference proved to be statistically significant (p < 0.001). The median length of the vector was 2.57 mm.

Conclusions:

A preoperative 3D bone thickness map could significantly improve implant position with regards to bone stock. However, the ideal position is located only a few millimeters from the actual placement. It remains to be demonstrated, if this accuracy can be realized during surgery.

Publication History

Publication Date:
23 April 2019 (online)