Three-dimensional printed titanium mesh combined with iliac cancellous bone in the reconstruction of mandibular defects secondary to ameloblastoma resection

Abstract

Background: The reconstruction of large mandibular defects is a challenge, and free vascularized bone flaps are most commonly used. However, the precision and symmetry of this repair are deficient, and patients have a risk of vascular embolism, flap necrosis, and donor site complications. Therefore, to explore an ideal alternative in mandibular reconstruction with high surgical accuracy and low complications is indispensable.

Methods: Seven patients with recurrent or large-scope ameloblastoma were enrolled in this study. All patients were provided with a fully digital treatment plan, including the design of osteotomy lines, surgical guides, and three-dimensional printed titanium mesh for implantation. With the assistance of surgical guide, ameloblastomas were resected, and custom 3D printed titanium mesh combined with posterior iliac bone harvest was used in mandibular reconstruction. A comparison was made between the discrepant surgical outcomes and the intended surgical plan, as well as the average three-dimensional deviation of the mandible before and after the surgery. At the same time, the resorption rate of the implanted bone was evaluated.

Results: All patients completed the fully digital treatment process successfully without severe complications. Image fusion showed that the postoperative contour of the mandible was basically consistent with surgical planning, except for a slight increase in the inferior border of the affected side. The mean three-dimensional deviation of the mandible between the preoperative and postoperative periods was 0.78 ± 0.41 mm. The mean error between the intraoperative bone volume and the digital planning bone volume was 2.44%±2.10%. Furthermore, the bone resorption rates of the harvested graft 6 months later were 32.15%±6.95%.

Conclusions: The use of digital surgical planning and 3D-printed templates can assist surgeons in performing surgery precisely, and the 3D-printed titanium mesh implant can improve the patient's facial symmetry. 3D printed titanium mesh combined with posterior iliac cancellous bone graft can be regarded as an ideal alternative in extensive mandibular reconstruction.

Keywords: Iliac cancellous bone; Mandible reconstruction,3D-printing; Surgical accuracy; Virtual surgical planning.

Fig. 1

A clear view of the range of mandibular ameloblastoma (A), and the osteotomy templates (B)

Fig. 2

The 3D titanium mesh reconstruction model of the mandible. (A) The contour of the affected side of the mandible (blue) was mirrored from the unaffected side. (B) The 3D titanium mesh reconstruction model of the mandible was designed

Fig. 3

All models and templates were printed on a 3D printer: osteotomy templates, original mandible model, and titanium mesh

Fig. 4

Resection of tumor and installation of titanium mesh. (A) The osteotomy templates were mounted. (B) The tumor was resected. (C, D) Titanium mesh after the installation was displayed in different angles

Fig. 5

The harvest and placement of cancellous bone from the iliac bone

Fig. 6

Volume of bone resection during surgery. (A) The osteotomy planes along the surgical incision were created. (B) The osteotomy planes were then superimposed on the preoperative mandible model. The blue plane is the bone resection plane during surgery, while the green plane is the bone resection plane in digital planning. (C) The block of bone resection during surgery was shown, and different areas from the digital planning are indicated by red arrows

Fig. 7

Discrepancy analysis of dental alignment between simulation and real result. (A) The 3D models of the patient’s preoperative mandible (blue) and mandible at 7 days postoperatively (gray) were imported into Geomagic Studio 2013 Software for alignment. (B) Discrepancy analysis of alignment between preoperative and postoperative mandible

Fig. 8

The CT images at seven days post-operation (upper) and six months post-operation (lower) Additional CT images taken at the same horizontal position were also displayed, with red arrows indicating the cancellous bone of the ilium