Computer-Aided Design for Three-Dimensional Titanium Mesh Used for Repairing Skull Base Bone Defect in Pediatric Neurofibromatosis Type 1

Abstract

Background: Sphenoid dysplasia is a distinctive but uncommon manifestation of neurofibromatosis type 1. The absence of the sphenoid greater wing allows the temporal lobe to prolapse into the orbit resulting in temporal base encephalocele and pulsating exophthalmos. Surgical procedures are aimed at preserving vision and improving ocular movement and cosmesis. This defect can be closed using bone grafts or titanium mesh. However, the results of this procedure are often unsustainable due to bone graft resorption and graft displacement. Methods: In this report, we describe a novel surgical technique, combining computer-aided design, stereolithography and neuronavigation to repair a temporal base skull defect in a 16-year-old female patient with neurofibromatosis type 1. A three-dimensional model of the skull base defect and a template for graft were first constructed according to the image data, then transferred to a real-size stereolithographic biomodel using a rapid prototyping technique. Results: The final graft of titanium mesh, which was intraoperatively fabricated based on the biomodel, was precisely orientated and securely fixed to the surrounding bone under frameless navigation. Long-term follow-up result proved this repair to be effective and durable. Conclusion: The approach combining computer-aided design, stereolithography and surgical navigation could help managing the complex lesions in the skull base and craniofacial area requiring rigid reconstruction.

Neuroimaging findings of extensive sphenoethmoidal dysplasia in NF1

“…Typically, surgical repair is considered based on the presence of symptoms, risks for significant complications, visual acuity, and the ability to undergo a major surgical procedure. The goals of therapy are to close the dura, restore the barrier between the orbit and the cranial fossae to preserve vision, and improve ocular movement [22]. Typically an intracranial approach is preferred over the lateral orbital approach as it provides better exposure of the bony defect and the optic nerve [23].…”

Quiste subaracnoideo y displasia del ala mayor del esfenoides en neurofibromatosis

“…Marchac (12) fue el primero en describir el abordaje intracraneal en 1984 con el uso de injertos óseos; sin embargo, se observaron resultados no satisfactorios y recurrencia. Como resultado de la reabsorción de los injertos óseos en la reconstrucción orbitaria, recientemente se han propuesto las placas de titanio para la reconstrucción de la órbita (13)(14)(15).…”

Clinical Applications of Rapid Prototyping Models in Cranio-Maxillofacial Surgery

“…Finally, implants from diverse sources, such as artificial bone (Cao et al, 2010), bone allotransfers , and titanium mesh (Wu et al, 2008), were manufactured to fit into cranial defects. An approach combining computer-aided design, SL models and surgical navigation could help manage complex lesions in the skull base and craniofacial area requiring rigid reconstruction (Wu et al, 2008). Finally, selectively coloured SL models have been used to construct surgical guides for dental implant placement.…”