Computer assisted reconstruction oft he mandible with simultaneous placement of dental implants for prosthetic rehabilitation

Introduction: Computer assisted design (CAD) is fast becoming a standard in microvascular fibular transplantation for mandible reconstruction as bony transfer can be performed with a high level of accuracy. Implant born prosthetic rehabilitation of these patients is still challenging however. In order to place dental implants at the earliest possible moment they should be inserted at the same time as the fibular bone graft is performed. To optimise the potential of virtual planning it is sensible to perform implant placement according to the opposing teeth/jaw and to position the mandibular bone in prosthetically optimal position, i.e. perform true backward planning as an integrated planning step along with the fibula osteotomy cuts and plate hole pre drilling. Materials and Methods: Using the Computed-Tomography (CT) data of each individual patient, virtual surgery was performed in order to resect and reconstruct the mandible. Simultaneous implant placement was included in the standard planning. The positioning of these implants was determined in collaboration with a prosthodontist specialised in tumour reconstruction. The fibular bone was then positioned according to the ideal position of the implants, based on the opposing occlusion, and cutting guides as well as a patient specific reconstruction plate ordered. The implants were placed extra-orally and the bone segments placed in their definitive position using a transfer splint. Postoperatively the precision of the reconstruction was checked by performing a second CT which was compared to the original plan. Results: Both the bone segments as well as the dental implants demonstrated good precision as compared to the planning data. Discussion: The inclusion of the drill-guides for dental implants, integrated in the patient-specific cutting guides for the fibula enabled to perform true digital backward planning with immediate guided implant placement in cases of mandibular reconstruction. Conclusion: We present a fully digitalized workflow for accurate dental implant placement integrated in the virtual osteotomy planning of vascularized free fibular bone grafts and implement this clinically to ensure early functional implant placement. Keywords: Implants, Fibula Free Flap, 3D planning, virtual surgery, complete virtual workflow, computer assisted reconstruction, facial defects