Optic nerve compression in craniofacial fibrous dysplasia: the role and indications for decompression.

Background: Fibrous dysplasia is a benign bone disorder in which craniofacial bones are involved in approximately one-fifth of cases. Optic nerve compression is one of its most potentially devastating complications. The approach to visual disturbance caused by disease involvement of the optic canal has been varied and controversial. This is especially the case with regard to surgical decompression, particularly prophylactic decompression. Methods: The authors performed a retrospective review of fibrous dysplasia patients who showed clinical or radiographic evidence of optic canal involvement over a 27-year period. Results: Twenty-two optic canals in 18 patients were affected by disease. Of these, 14 optic canals had symptoms (i.e., affected visual acuity or visual field). Twelve therapeutic and six prophylactic optic nerve decompressions were performed in total. At long-term follow-up (of at least 1 year), there was deterioration of vision in one-third of the patients who had undergone prophylactic decompression. Therapeutic decompression seemed to prevent visual deterioration in slightly more than half of the patients, with the majority having improvement in vision. There was visual deterioration in the remaining patients within this group, with most ultimately ending up with blindness. Conclusions: Therapeutic optic nerve decompression is advocated in patients with continuous deterioration of vision. Prophylactic decompression, in contrast, is not advised to be performed as a primary surgical procedure but as a procedure secondary to excision of lesion in the anterior skull base during the same operation.