Transcranial Correction of Orbital Neurofibromatosis

Abstract

Neurofibromatosis is a systemic disease that often produces striking disfigurement. Orbital manifestations are common and include sphenoid dysplasia with or without infiltration of the periorbital soft tissues. The resultant deficiency of the posterolateral orbital wall may lead to protrusion of the temporal lobe into the orbit, displacement of the globe, and pulsatile exophthalmos. Treatment at our unit has consisted of transcranial orbital reconstruction with bone grafts and periorbital soft-tissue correction. Observation of complete bone graft resorption in one patient prompted an assessment of the Australian Craniofacial Unit's experience with particular attention paid to the stability of operative correction. Of 36 patients with head and neck neurofibromatosis treated during the period from 1981 to 1995, 14 patients underwent transcranial correction of orbital deformities secondary to sphenoid dysplasia. The treatment and outcomes of this transcranial group are reviewed. The most notable finding was that of recurrent globe pulsation in four patients following initial resolution. Computed tomography scans have documented partial to complete bone graft resorption in three of these patients. Titanium mesh is now being utilized to provide a more durable reconstruction.

Orbital/Periorbital Plexiform Neurofibromas in Children with Neurofibromatosis Type 1

“…This should be considered on a case by case basis and is a more critical issue when associated with a seeing eye. 63 …”

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

“…Autogenous bone graft was originally used for the repair of the skull base defect, but the problem of bone resorption following surgery has been mentioned by many authors in the literature [7, 8]. Snyder et al[ 7] reviewed their results in 14 patients who had undergone transcranial repair with autogenous bone graft in a period of follow-up ranging from 6 to 17 months and found that recurrent globe pulsation following initial resolution was observed in 4 patients. They also observed that partial or complete loss of bone could be found even after rigid fixation of grafts in a well-vascularized recipient site.…”

“…The exact mechanism of bone graft resorption remains unclear. Snyder et al[ 7] suggested that the problem might be related to pulsation of the temporal lobe, tumor erosion and the nature of the local environment (soft tissue dysplasia). However, the osseous quality of the graft may also play an important role [13].…”

“…The most distinctive characteristics include unilateral defects in the greater sphenoid wing and enlargement of the ipsilateral middle cranial fossa [5, 6]. The degree of visual impairment is related to the distortion and/or displacement of the globe and optic nerve [7]. Operations for these lesions are aimed at preserving vision and improving ocular movement and cosmesis.…”

“…Although various methods of reconstructing the skull base defect have been proposed, some issues remained to be solved. The major problems of this surgery are bone graft resorption and implant displacement preventing long-term restoration of the lateral wall of the orbit [4, 7, 8]. The progressive and degenerative nature of the disease is attributable to the recurrence of orbital symptoms.…”