Abstract
Mandibular reconstruction for wide defects remains a challenge. Although vascularized free flaps are the gold standard for wide defects due to excision of mandibular neoplasms, a less invasive, more aesthetic treatment modality should be considered, especially for benign tumors of young patients. Five patients who received a custom-made titanium mesh cage for transplantation of autologous iliac particulate cancellous bone and marrow for the reconstruction of wide mandibular defects due to ameloblastoma were evaluated. Titanium mesh cage was preoperatively customized and prepared by patient-specific modeling for each case. The segmental resection of mandible for each cases was planned by preoperative computer simulation, and precisely performed with intraoperative surgical navigation systems. Thus, customized titanium mesh cage was perfect fit for all cases. All cases were followed-up for at least 1 year. Two patients had a small fistula because of bacterial infection 1 week after surgery. There was no titanium mesh exposure in the fistula, and local irrigation for several days healed it. Although one patient had a small fracture of the titanium mesh cage 6 months after the surgery, mandibular bone continuity was maintained. A viable, less invasive, more aesthetic alternative to the standard bony reconstructive strategy for wide mandibular defects was described. Further studies to modify the mesh cage design for better outcomes and reconsideration of the materials inducing and replacing the new bone are needed.
Highlights
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Mandibular reconstruction for wide defects remains a challenge for the maxillofacial surgeons.
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5 cases with mandibular defect were reconstructed by titanium mesh cage and Iliac particulate cancellous bone and marrow.
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Titanium mesh cage was preoperatively customized for individuals was according to patient-specific modeling.
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Segmental resection of mandible was precisely performed with intraoperative navigation system.
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A Less invasive and more aesthetic alternative to the standard reconstructive strategy for mandibular defects was described.
1
Introduction
The mandible, which forms the lower third of the facial skeleton, is an important structure for oral function, esthetics, and quality of life (QOL) [ , ]. In a case with mandibular defects due to a cyst or tumor, careful consideration must be given to morphological and functional conservation. Three-dimensional (3D) skeletal models can be used for reconstruction surgery in the maxillofacial region [ , ], and it has been reported that these models are useful for the fabrication of custom-made titanium mesh cages [ , ]. Although application of custom-made titanium mesh cage and autologous grafts of particulate cancellous bone and marrow (PCBM) over a small range has been reported [ ], they have rarely been applied for wide defects. Any complications (e.g. morphological deformity, titanium mesh cage exposure, and/or fracture) are due to unfitness of the cage for residual segments of the mandible. Thus, segmental osteotomy must be accurately performed according to the preoperative simulation. A case series of reconstruction with individualized titanium mesh cages following wide excision of mandibular tumors under an intraoperative navigation system is presented.
2
Presentation of cases
Between 2014 and 2020, reconstruction with individualized titanium mesh cages was performed following wide excision of mandibular tumors under an intraoperative navigation system for five male patients. The different available treatment strategies were discussed with the patients, and informed consent was obtained from all patients. The patients ranged in age from 27 to 43 years (mean age, 36.0 years). They were diagnosed with ameloblastoma that required segmental mandibular resection. The patients were followed-up for 16–85 months (mean, 44.6 months). Table 1 shows the demographic and clinical characteristics of the five patients. The case series was approved by the local ethics committee of the hospital associated with the authors’ institution (No. 21-039-B).
Digital imaging and communications in medicine (DICOM) data were obtained by cone-beam computed tomography (CBCT) scans before the surgery. The data were imported into iPlan CMF 3.0 (BRAINLAB, Munich, Germany), and the resection margin was determined according to the clinical and 3D radiographic findings ( Fig. 1 ). A 3D mandible model was designed with mirror imaging of the opposite tumor-free side and produced by computer-aided manufacturing on a 3D printer (Connex 260, Stratasys Ltd. Minnesota, USA). Then, a custom-made mesh titanium cage was fabricated in the remote laboratory on the 3D skeletal model (ULTRA FLEX MESH CUSTOM, Okada Medical Supply, Tokyo, Japan) ( Fig. 2 ). The thickness of the titanium mesh cage was 0.6 mm, and it had a basic hexagonal polygonal shape designed to have high 3D flexibility.
Mandibular segmental resection was performed with the KICK Navigation System (BRAINLAB) to which the data from the preoperative simulation were imported. A headband with a reference device was applied to the patient’s head under general anesthesia, and a wafer with a reference marker used for registration and calibration of 3D positional information for the intraoperative navigation system was also applied [ ]. After the initial registration of 3D positional information, the consistency of the positional information of the CBCT data of the intraoperative navigation system and the actual positional information of the patient was confirmed ( Fig. 3 A and B). A combined extraoral/intraoral approach was used, and resection margins were completed using Piezosurgery (GE Medical Technology, Carasco, Italy) according to the navigation system ( Fig. 4 A). The custom-made titanium mesh cage was then inserted and fixed to the distal and/or proximal mandibular stumps with bicortical screws. After the mesh cage was filled by PCBM, which was harvested from the same or both sides of the anterior iliac crest ( Fig. 4 B), intraoral and extraoral closure was finally completed in multiple layers.
