Background : Sphenoid dysplasia is a manifestation of Neurofibromatosis type 1 (NF1), and occurs in over 7% of patients. Herniation of the temporal lobe through skull base defect produces spheno-orbialencephalocele. Surgical goals are vision and extraocular muscle preservation, as well as aesthetic condition improvement. Orbital anatomy reconstruction requires a combination of bone grafts, osteosynthesis and titanium meshes. Success and stability depend on the correct planning, reabsorption rate, brain pushing and neurofibromas growth.

Method : We present two cases of NF1 and spheno-orbital encephalocele, treated between 2012 and 2013. One and 2-year-old males presented with craniofacial deformity, dystopia and pulsating proptosis. Preoperative evaluation includes ophthalmologic assessment; computerized tomography and magnetic resonance. Studies demonstrate major sphenoid wing dysplasia; middle cranial fossa enlargement and in addition a plexiform neurofibroma of the III cranial nerve was also diagnosed. Planning starts with tridimensional reconstruction of DICOM images with the software Materialise, virtual model is generated with a specular orbital cavity to the non-affected side. Afterwards a stereolithographic (STL) model is fabricated. By means of an intracranial and lateral orbit approach, temporal lobe is retracted and bone defect expose. Over the STL model, the Titanium mesh is adapted, a custom-made graft is achieved for sphenoidal defect reconstruction.

Results : Follow-up period is longer than 6 months. Progressive craniofacial deformity improvement was achieved, besides proptosis recovery. Neither patient developed any important perioperative complications, and the postoperative radiological tests showed a complete encephalocele resolution.

Conclusion : Skull base reconstruction in sphenoid wing dysplasia can be accurately accomplished by computer-aided design technology. It is a safe procedure that decreases incorrect mesh adaptation and mobility, bone resorption, and encephalocele relapse.

Key words : encephalocele; orbital; neurofibromatosis; computer-aided design