Material and Methodology:
The study was done to evaluate the feasibility and role of a 3D patient-specific biomechanical model for the management of tongue tumour. The study was conducted at the HealthCare Global Enterprises Cancer Centre, Bangalore, India. The technical support for developing the 3D patient-specific biomechanical model was provided by Anatomiz3D LLP, Mumbai, India.
In the present study two patients, diagnosed with Carcinoma Tongue, sub-site lateral border of the tongue were included. These patients underwent a pre-operative Magnetic Resonance Imaging (MRI) of the head and neck region at our center. The images were acquired on a 3 Tesla SIEMENS Skyra ® Magnetic Resonance Imaging machine without contrast with 48 channels in multi-planar, multi-sequence of head and neck region with a pixel resolution of 0.9 x 0.9 x 0.9 mm3.
These patients were informed about the use of a 3D biomechanical patient-specific model for treatment planning and execution and consented for the same.
The data acquired by the MRI was obtained in a digital DICOM format. Using Materialise Mimics Innovation Suite 19 ®, Belgium, an FDA, and CE approved software DICOM data was imported, visualized, edited and segmented. Open-source software, MakerBot MakerWare 2.4.1, Brooklyn NY USA, was used to slice the 3D model, which serves as input data for the 3D Printer (Figure 1).
Flashforge ‘Creator-pro’3D Printer ®, Zhejiang, China was used. Fused Deposition Modeling (FDM) technology was used to print the tumour and uninvolved tongue in two different colors for easy identification. Recreus Filaflex ® Elda, Spain flexible filament 1.75 mm spool was the print material. The filament melts because of high temperature at the nozzle and liquefied plastic is deposited on the print bed layer by layer as the previous layer cools (Figure 2).
A team of Head and Neck Surgical Oncologist, Reconstructive surgeons, Anaesthetist, Physician, and Speech-Language pathologist, preoperatively evaluated the patients. The 3D biomechanical patient-specific tongue model was used by the team to frame a treatment and rehabilitation plan taking into account the patient preferences and needs.
These patients underwent a partial/ hemiglossectomy with neck dissection. The 3D model served as a guide for margins. As a preoperative assessment of volume loss was now possible, the reconstructive team could simultaneously start the appropriate flap harvest. The model also enabled accurate molding of the flap into the surgical defect.
Oral swallow and speech rehabilitation were initiated from postoperative day 3. One patient was able to take orally adequately, the nasogastric tube was removed.