Precise maxillofacial soft tissue reconstruction: A combination of cone beam computed tomography and 3dMD photogrammetry system

Abstract

Introduction: The reconstruction of both extra- and intra-oral soft tissue defects, particularly in restoring the morphology of the lip and the corners of the mouth, has posed a significant challenge for surgeons. Inappropriate methods often lead to maxillofacial deformity which then causes psychological and functional problems. This study aimed to address the challenge of reconstructing extensive and complex maxillofacial soft tissue defects, mainly focusing on the lip, the corners of the mouth, and the surrounding areas.

Materials and methods: We developed a reconstruction approach by combining the 3dMDface System (3dMD) with the cone beam computed tomography (CBCT). Firstly, with the extra-oral incision line, we evaluated the shape and the size of the extra-oral defect with 3dMD digitally. Then we used the corresponding maxillary and mandible tooth positions to record the intra-oral defect, which was then converted to digital images by combining 3dMD and CBCT. The islands of the anterolateral thigh perforator flap were then designed after the locations of the perforators were detected with Doppler ultrasonography.

Results: A clinical case diagnosed as dermatofibrosarcoma protuberans was presented to illustrate the approach. The patient's tumor resection and the size of multiple defects were measured and simulated via the virtual surgery system. A three-island perforator flap from the descending branch of the lateral femoral circumflex artery was designed accurately. Two weeks postoperatively, the flap was healed as anticipated and the patient was satisfied with the profile.

Conclusion: The combination of the 3dMD and CBCT technologies improves the accuracy and fitness of extra- and intra-oral soft tissue reconstruction.

Keywords: 3dMD; CBCT; Digital planning; Maxillofacial surgery; Soft tissue reconstruction.

Fig. 1

The extra- and intra-oral flap islands were designed by the combination of 3dMD and CBCT digitally. (1A) Yellow area shows the size and shape of the extra-oral flap. (1B) Yellow area shows the size and shape of the intra-oral flap.

Fig. 2

The Surgical method diagram. (2A) The resection range was marked 5 mm outside the tumor boundary. (2B) Weber-Ferguson incision was used for enlarged tumor excision. (2C) The ALTPs were harvested for extra- and intra-oral reconstruction. (2D) Expected postoperative recovery.

Fig. 3

Preoperative examination of the patient. (3A-C) Tumors and the ranges marked by lines. (3D-E) Intra-oral examination. (3F) Pathological diagnosis in 20 × . (3G) Pathological diagnosis in 40 × . (3H-J) MRI images.

Fig. 4

Digital simulation and reconstruction design. (4A) Three-dimensional profile made with the 3dMDface System digitally; excision margin was marked with red line; the extra-oral defect was separated into 2 areas. (4B) The shape of flap island 1. (4C): The shape of flap island 2. (4D-E) CBCT image was projected to 3dMD image to design the intra-oral flap. (4F) The shape of the intra-oral defect region. (4G-H) The curved surface of the flap island 2 was expanded into a plane. (4I) The flap island 2 was printed in a 1:1 ratio. (4J-L) Three perforators from the descending branch were located on the anterolateral thigh region with the use of color Doppler flow imaging. (4M-N) The flap islands were printed and mapped on the anterior thigh to design the three-island perforator flap.

Fig. 5

Intraoperative and postoperative images of the patient. (5A) The tumors were removed to the bone surface. (5B-D) Postoperative photographs of the patient when hospital discharge. (5E) Front 3dMD image before surgery. (5F) Side 3dMD image before surgery. (5G) Front 3dMD image when hospital discharge. (5H) Side 3dMD image when hospital discharge.