Optic Nerve Decompression for Orbitofrontal Fibrous Dysplasia

Abstract

Orbitofrontal fibrous dysplasia often involves the bony orbit and the optic canal. Although fibrous dysplasia reportedly produces compression of the optic nerve leading to visual disturbances, optic nerve decompression in patients without clinical signs of optic neuropathy is still controversial. We describe two patients with orbitofrontal fibrous dysplasia without signs of visual disturbance and one patient with McCune-Albright syndrome and progressive visual impairment. Optic nerve decompression was performed prophylactically for two patients and therapeutically for one patient through the transcranial extradural route. Dystopias and craniofacial deformities induced by fibrous dysplasia also were corrected. The micropressure suction-irrigation system was especially effective for decreasing heat transfer and thereby preventing thermal injury of the optic nerve. The orbitofrontal area was reconstructed from cranial bone, iliac bone, and ribs. Postoperative follow-up revealed no disturbances in visual function and no evidence of cerebrospinal fluid leakage. These findings suggest that optic nerve decompression may be effective in preventing visual disturbances with minimal risk of other neurological sequelae. Subsequent orbital reconstruction yielded satisfactory cosmetic results.

Visual Impairment in Orbitofrontal and Sphenoidal Fibrous Dysplasia Associated with Sphenoid Sinus Mucocele

“…Treatment with corticosteroids has been used successfully in patients with fibrous dysplasia as a temporary measure in patients who have loss of visual acuity [27], but it has not been used in patients complaining of recurrent of visual acuity [21]. Surgical treatment is controversial and consists of preventive or therapeutic decompression of optical channel [1,[28][29][30], which leads many times to loss of visual acuity in the affected eye or to an increased incidence of visual acuity changes [23,28].…”

“…Fibrous dysplasia is an abnormal development of a bone mass in terms of structure and growth [1]. This is a rare disease with a benign evolution caused by the postzygotic activating mutations of the GNAS gene [2] on chromosome 20q13 [3] found in 71.9-86% of fibrous dysplasia cases [4] and that results in the inhibition of the differentiation and proliferation of the bone-forming stromal cells that leads to the replacement of the bone with fibrous tissue and immature thin bone trabeculae.…”

Fibrous Dysplasia of the Orbital Region: Current Clinical Perspectives in Ophthalmology and Cranio-Maxillofacial Surgery

“…Patients with recent-onset visual deterioration usually benefit greatly from optic nerve decompression and may subsequently regain normal vision 5,11,[37][38][39][40][41] ; however, in patients who have been blind for more than 1 month, optic nerve decompression has always failed to restore their sight. 7,11,25 Controversy surrounds the surgical treatment of FD involving the encasement of the optic nerve canals in patients whose vision is normal.…”

Optic Nerve Decompression for Orbitofrontal Fibrous Dysplasia: Recent Development of Surgical Technique and Equipment

“…Descriptions of optic nerve decompression in 3 patients (Patients 2 to 4) have been published previously. [24][25][26][27][28][29][30][31]…”

“…We have already reported the usefulness of combined methods with the high-speed drill and continuous suction-irrigation system for optic nerve decompression in orbitofrontal fibrous dysplasia. 24 We recently performed optic nerve decompression using ultrasonic bone curette in two patients with orbitofrontal fibrous dysplasia. The present article describes patients with orbitofrontal fibrous dysplasia who underwent optic nerve decompression.…”