Clinical Application of Individualized 3D-Printed Templates in the Treatment of Condylar Osteochondroma

[Comparison of the virtual surgical planning position of maxilla and condyle with the postoperative real position in patients with mandibular protrusion]

OBJECTIVE

To compare the difference between virtual surgical planning (VSP) position and postoperative real position of maxilla and condyle, and to explore the degree of intraoperative realization of VSP after orthognathic surgery.

METHODS

In this study, 36 patients with mandibular protrusion deformity from January 2022 to December 2022 were included. All the patients had been done bilateral sagittal split ramus osteotomy (SSRO) combined with Le Fort Ⅰ osteotomy under guidance of VSP. The VSP data (T0) and 1-week postoperative CT (T1) were collected, the 3D model of postoperative CT was established and segmented into upper and lower jaws in CCMF Plan software. At the same time, accor-ding to the morphology of palatal folds, the virtual design was registered with the postoperative model, and the unclear maxillary dentition in the postoperative model was replaced. Then the postoperative model was matched with VSP model by registration of upper skull anatomy that was not affected by the operation. The three-dimensional reference plane and coordinate system were established. Selecting anatomical landmarks and their connections of condyle and maxilla for the measurement, we compared the coordinate changes of marker points in three directions, and the angle changes between the line connecting the marker points and the reference plane to analyze the positional deviation and the angle deviation of the postoperative condyle and maxilla compared to VSP.

RESULTS

The postoperative real position of the maxilla deviates from the VSP by nearly 1 mm in the horizontal and vertical directions, and the anteroposterior deviation was about 1.5 mm. In addition, most patients had a certain degree of counterclockwise rotation of the maxilla after surgery. Most of the bilateral condyle moved forward, outward and downward (the average distance deviation was 0.15 mm, 1.54 mm, 2.19 mm, respectively), and rotated forward, outward and upward (the average degree deviation was 4.32°, 1.02°, 0.86°, respectively) compared with the VSP.

CONCLUSION

VSP can be mostly achieved by assistance of 3D printed occlusal plates, but there are certain deviations in the postoperative real position of maxilla and condyle compared with VSP, which may be related to the rotation axis of the mandible in the VSP. It is necessary to use patient personalized condylar rotation axis for VSP, and apply condylar positioning device to further improve surgical accuracy.

Preliminary study of 3D printing technology for extracorporeal positioning guide assisted ultrasound-guided microwave ablation of the liver

BACKGROUND

We designed a 3D-printed extracorporeal positioning guide for assisting ultrasound-guided microwave ablation of the liver and observed its effectiveness.

RESEARCH DESIGN AND METHODS

13 patients with liver cancer were selected, and their CT data were obtained. The CT data is reconstructed in 3D by computer software Mimics to create a 3D model. The 3D-printed in vitro positioning guides were designed by 3-Matic and fabricated using 3D printing technology. Finally, it is applied to the clinic, and its effect is observed.

RESULTS

The preliminary design of a 3D printed extracorporeal positioning guide was applied to the clinic, and the efficiency of assisted ultrasound positioning was 76.92% (10/13), with three patients requiring repositioning. The efficiency of the 3D printed extracorporeal positioning guide technique was 76.92%, a CT examination was performed one month after surgery, and three patients had residual lesions.

CONCLUSIONS

3D-printed extracorporeal positioning guides can assist ultrasound in localizing tumors during liver microwave ablation and reduce repeated punctures. It makes percutaneous microwave ablation of the liver more precise and safe. However, the current study sample is small, there are still apparent shortcomings, and long-term clinical studies are needed to prove its effectiveness.