7th ICHNO Abstract book

7th ICHNO 7 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 14 – 16 March 2019 Barcelona, Spain __________________________________________________________________________________________ page 89

characteristics were optimized to allow drilling without fracture or fusion. In our Anatomy Lab, the endoscopic transclival approach was performed in all heads under neuronavigation guidance to obtain a defect as close as possible to the predicted one. Several tests of plug fixation were performed. In one head, cervical dura was sutured around a catheter inserted in the subdural space so that the intradural compartment became a closed system. A stained fluid was injected through the catheter, and a vertical graded tube was connected to it so that the intracranial pressure could be measured as the height of the fluid column in the graded tube (cmH2O), and a leakage test of skull base reconstruction could be performed. In all cases, post- procedure CT was performed to check correct placement of the plug. Results In all 3 heads the correspondence between the real and predicted dimension of the clival defect was optimal. Two fixation techniques were explored: 1) by pressure with an autologous graft (fig. 1 A-B); 2) with screws and plates (fig. 2 A,B). The former provided a good proximity between the scaffold and the bony edges of the defect (fig. 1 C-H). Accordingly, the maximal pressure of CSF-leak test was satisfactory (18 cmH2O; physiological CSF pressure: 10-16 cmH2O). Its main flow was the relevant pressure needed to interlock the plug in the defect. Fixation by plates and screws was technically demanding (4-hand technique, with a screwdriver inserted through the mouth), but provided steady placement of the plug. Screws were driven under neuronavigation guidance; plug and screws placement was correct (fig. 2 C-D).

Fig. 1

Fig. 2

Conclusion The production process (polymer characteristics, 3D printing) was successfully defined; the technique to fix the scaffold needs further tests, but preliminary results are promising. Our data suggest that the use of 3D printing for personalized skull base reconstruction can overcome the main limitations of current techniques in critical sites (i.e. clivus), such as patient-specific geometrical complexity of