Single staged transorbital neuroendoscopic (TONES) approach of managing pulsatile proptosis using patient specific implant (PSI) in orbitopalpebral neurofibromatosis

Sphenoid wing dysplasia and plexiform neurofibromas are among the diagnostic criteria for neurofibromatosis 1 (NF1), an autosomal dominant neurocutaneous disorder. It has been called by different names based on the involved anatomic areas such as orbito-palpebral, orbito-temporal, and orbito-facial plexiform neurofibromatosis. Management of the deformity in plexiform neurofibromatosis is challenging given the ill-defined, infiltrative, and vascular nature of the lesion, associated with a defect in the greater wing of sphenoid, resulting in pulsatile proptosis. A staged multidisciplinary approach has been described in literature to correct the bony dysplasia followed by correction of the soft tissue components. Craniofacial bony deformities have been mostly described to be managed via craniotomy approach by neurosurgeons whereas the periorbital debulking of tumor and correction of canthal dystopia and blepharoptosis is done by ophthalmic plastic surgeons at a later stage. Bony defects have been traditionally managed with the help of bone grafts or titanium mesh or a combination of both, but, more recently, the use of patient specific implants has also been described which offer bespoke reconstruction. A single staged transorbital approach to reconstruct the skull base defect and orbital aperture along with palpebral debulking and levator resection has not been described till date to the best of the authors' knowledge. Here, the authors describe a case of orbitopalpebral plexiform neurofibromatosis with pulsatile proptosis managed via a single staged transorbital approach using computer-assisted 3 dimensional (3D) virtual surgical planning.