Surgery for Optic Nerve Injury: Should Nerve Sheath Incision Supplement Osseous Decompression?

Objective: To evaluate the benefits and risks of performing an optic nerve sheath Incision to supplement standard osseous optic canal decompression for traumatic Optic neuropathy. Methods: Morc-after analysis of 57 cases undergoing optic nerve decompression at a tertiary, referral centre from 1988-2006. Fifty-five c cases had adequate post surgical follow-up for evaluation for improvement. Group A (n=35) had decompression of the osseous optic canal and surgical slitting of the optic nerve sheath; Group B (n=22) had osseous decompression alone. The groups, Were comparable for age, injury severity, and injury-surgery interval. Main outcome measure: Percentage visual improvement, which was calculated by conversion of the pre- and post-intervention visual acuity measurements to the logarithm of the minimum angle of resolution (log MAR) scale. Results: No significant recovery was noted in subjects with persistent complete blindness (PL-ve vision). In subjects with residual pre-op vision, the quantum of recovery was greater in Group A than In Group B (46% and 33% respectively, p = 0.10). The difference was especially evident in subjects with no optic canal/posterior orbit fracture (p = 0.07). Three cases with the sheath incision developed transient CSF rhinorhea in the initial experience, but this was subsequently alleviated with modification of surgical technique. Conclusion: The addition of optic nerve sheath incision to osseous decompression may improve recovery in optic nerve especially in subjects without optic canal fracture.