Reconstruction and Optic Never Decompression Following the Removal of Fibrous Dysplasia in the Orbit and Cranial Base

ABSTRACT

Fibrous dysplasia in the orbit and cranial base may involve the optic canal. Although fibrous dysplasia is benign, it may produce a mass effect along the course of the optic nerve which can then induce visual disturbance as well as contour deformities of the skull and facial bone. The treatment of fibrous dysplasia in the orbit and cranial base is to resect the lesion as much as possible and then reconstruct immediately. As well, if there is any evidence of optic canal involvement and disease progression, the treatment of fibrous dysplasia may include optic nerve decompression. It is generally understood that some patients experience improvement of visual function after optic nerve decompression. We performed radical excision and reconstruction by means of autogenous calvarial bone graft and methylmethacrylate in 7 cases. The autogenous calvarial bone was used to reconstruct the orbit. The methylmethacrylate was used to reconstruct bony defect in the temporal area. The orbit was reconstruced into one block which was made of autogenous calvarial bone with a microplate and screw. This method is superior compared to the previous multifragment wiring method with regard to stability, operation time, and appearance. The patients in our series showed satisfactory appearance. In 6 cases, we performed optic nerve decompression. Therapeutic optic nerve decompression was done in 3 cases and prophylatic optic nerve decompression was done in the others. Following therapeutic optic nerve decompression, visual acuity was improved in 2 cases while the others showed a decrease in visual acuity. There was no change of visual acuity and visual field in 1 case after prophylactic optic nerve decompression. However, the others showed decrements in visual acuity or visual field. Therefore, we believe that more attention should be paid during optic nerve decompression procedure and strict indications to that procedure should be applied.