Last month we were asked to collaborate in planning a mandibular tumor resection associated with concomitant reconstruction of the damaged area. Due to the patient’s young age and the fact that the reconstruction concerned about 60-70% of the mandible area, the doctors made a decision to treat the patient with partial mandibulectomy and simultaneous reconstruction with fibular bone grafts fixed with a custom-made titanium plate.
The patient had reported to a dentist with a toothache. It was originally a harmless symptom, which led to a shocking diagnose – high-grade osteosarcoma. Osteosarcoma is a rare malignant bone tumor with a predilection for adolescents and young adults. Because it is likely to have very small areas of cancer spread that can’t be detected with tests, the patient was treated with chemotherapy. If chemotherapy is not given, the cancer is more likely to come back after the surgery.
The extent of the tumor and its aggressiveness led to radical surgical treatment. The tumor resection involved about 65% of the mandible from the right condyle to the left mandibular body. The surgical plan included complete resection of the tumor, part of the soft tissue of the oral cavity and the damaged oral mucosa. The doctors used vascularized free fibula flap to reconstruct the defect of the lower face. The osseous flap was divided into three segments which were affixed to the individual 3D-printed titanium plate to restore the mandibular border. Involvement of the mandibular condyle made the reconstruction more challenging.
Virtual surgery planning
Radical tumor resection of a mandible segment without adequate reconstruction leaves large and multi-component defects involving aesthetic and functional sequelae leading to a loss of quality of life. That is why appropriate pre-operative evaluation and planning are particularly important. To precise perform the tumor resection and then reconstruction of the patient’s face shape, the virtual surgery planning had been used. In order to minimize intra and postoperative complications during the preoperative planning engineers had to consider factors like location and length of the vascular pedicle, the place of graft resection as well as the course of the mandibular nerve.
Engineers from Customy closely co-operated with the doctors though a dedicated online platform which facilitated 3D virtual pre-operative planning (psPortal). Remote access to the platform enabled doctors to verify whether the proposed solutions were tailored to them and the patient’s needs. Among factors that influence virtual planning substantially, communication between surgeon and engineer is crucial.
A personalized reconstruction box
The result of the pre-operative preparations was the patient-specific reconstruction box containing:
- a custom-made 3D implant made of titanium alloy Ti6Al4V
- a cutting guide for tumor resection
- a cutting guide for the fibula bone osteotomy
- anatomical models of the mandible (before and after the surgery)
- anatomical model of the fibula
The implant was designed and tailored-made according to the patient’s mandible shape to match exactly to the anticipated bone loss after tumor resection. This individual reconstructive plate was used to stabilize fibular bone grafts and to reconstruct the mandible border with the mandibular condyle. Such design of the implant allowed not only to restore the patient’s face shape but also to stimulate her earlier return to a normal diet based on solid food.
The surgery
The surgery was simultaneously performed by two teams. The resection team was responsible for radical resection of the tumor, whereas the reconstruction team was responsible for harvesting bone grafts and immediate mandible reconstruction using vascularized fibula flap fixed to the custom-made implant.
The surgical treatment included the following stages:
- fitting and fixing the resection cutting guide
- tumor resection with a safe margin
- fitting and fixing the osteotomy cutting guide
- the free fibula flap osteotomy
- detaching the free fibula flap from the donor site
- inserting the fibula graft in the mandibular region and making the micro-anastomoses to preserve the flap viability,
- positioning and fixation the fibula grafts with the individual implant
- attaching muscles with skin island to the implant through special clamps
Results
Surgical planning is most effective when it is tailored to the patient and give more precise control of the final outcome. The patient with tumor invading over 65% of her mandible underwent reconstruction using vascularized free fibula flap and the custom-made implant. Patient-specific surgical guides allowed the precise tumor resection and the exact fibula osteotomy with harvesting the exact amount of tissue needed for the reconstruction. The total surgery time was 9 hours. Facial reconstructions have always been very challenging for surgeons, therefore, precise virtual pre-surgical planning allowed surgeons to obtain very good final functional and aesthetic results and the patient feels very well.
