3D Printing and Intraoperative Neuronavigation Tailoring for Skull Base Reconstruction after Extended Endoscopic Endonasal Surgery

Objective Endoscopic endonasal approaches have been increasingly performed for the surgical treatment of various skull base pathologies. Despite advances in reconstruction techniques of the surgical defect, cerebrospinal fluid leakage remains an ongoing issue. In this study, we assessed the potential use of modern multimaterial 3D printing and neuronavigation to help model and develop patient-specific prostheses tailored to the surgical defect for reconstructive purposes.

Methods Extended endoscopic endonasal skull base approaches were performed on three human cadaveric heads. Pre- and intraprocedure CT scans were acquired and used to segment and design extended as well as tailored cadaver-specific skull base models. 3D printers were used to produce multimaterial prostheses with different core/edge interfaces which were implanted during the reconstruction of the defect. We tested a novel off-label application of intraoperative landmark acquisition feature available on neuronavigation platforms to transfer the registration from the cadaver to the prosthesis, helping to tailor the models based on the intraprocedural defect. Additional features to avoid areas of dependencies as well as structural additions to help maneuverability were manually added to the prostheses.

Results We created prostheses based on both the preoperative and intraoperative CT scans. The intraoperative navigation transfer offered sufficiently accurate data to help tailor the preprinted extended skull base prostheses to match the intraprocedural defect. Successful implantation of the skull base prostheses was achieved in all specimens. The progressive flexibility gradient of the models’ edges offered the best compromise to ensure intranasal maneuverability, while maintaining sufficient anchoring and structural stability. Prostheses printed based on intraprocedure CT scans were accurate in shape but were consistently undersized in all three specimens.

Conclusion Our study demonstrated that preoperative 3D printing of patient-specific skull base models is a feasible option for extended endoscopic endonasal surgery. The careful spatial modeling and the use of a flexibility gradient in the design helped achieve the most stable reconstruction and neuronavigation can help further tailor the preprinted prostheses to optimally reconstruct the surgical defect.