Fibrous Dysplasia: Management of the Optic Canal

Background: Fibrous dysplasia is an abnormal growth of bone that can lead to severe facial disfigurement. A dreaded outcome is compression of the optic nerve, leading to blindness. Controversy has surrounded the role of optic nerve unroofing for circumferential involvement of the optic canal. At present, many neurosurgeons unroof the nerve therapeutically in the setting of optic nerve dysfunction. Prophylactic unroofing (i. e., unroofing the nerve prior to the development of visual symptoms) has been previously proposed, although reported outcomes have been mixed. The authors present their long-term results of patients who have undergone optic nerve unroofing. Methods: From 1975 to 2012, patients with fibrous dysplasia were investigated. Their age, demographics, operative procedure, optic nerve involvement (radiologically and clinically), and long-term outcomes and complications were recorded. Results: Over 37 years, the senior author (S. A. W.) operated on 32 patients with fibrous dysplasia. Average follow-up was 5 years. Nine patients underwent optic nerve unroofing. Two patients had bilateral unroofing. Three patients who underwent therapeutic optic nerve unroofing ultimately went on to complete vision loss. The remaining seven patients who underwent prophylactic unroofing had no immediate postoperative visual compromise. Conclusions: Therapeutic optic nerve unroofing is advocated in fibrous dysplasia patients with continuous deterioration of vision. However, the authors believe prophylactic unroofing is safe, and it should be performed not necessarily as a primary surgical procedure, but as a procedure along with excision of fibrous dysplasia in the anterior skull base during the same operation performed for orbitocranial deformity.