Incidence of optic canal fracture in the traumatic optic neuropathy and its effect on the visual outcome.

OBJECTIVE: To correlate the intraoperative endoscopic findings with high-resolution CT (HRCT) for the diagnosis of optic canal fractures (OCF). To compare the visual outcome of patients with different types of OCF and without.

DESIGN: A retrospective, comparative case series.

PARTICIPANTS: 1275 consecutive patients (1275 eyes) with indirect traumatic optic neuropathy (TON).

METHODS: Altogether, 1275 patients who underwent endoscopic transethmoid optic canal decompression (ETOCD) for unilateral indirect TON were reviewed from 1 October 2006 to 30 September 2014. HRCT performed prior to surgery were compared with findings during surgery. The visual outcomes before and after surgery were also compared.

MAIN OUTCOME MEASURES: The presence and type of OCF detected by HRCT and during surgery; visual acuity prior to surgery and at 3 months after surgery.

RESULTS: A total of 1275 patients (1275 eyes) were included, with 708 patients that had OCF visible on HRCT image. During surgery, an additional 187 (20.9%) patients with OCF were noticed. Among these, 136 had undisplaced fractures, most of which were linear intracanalicular fractures. The initial visual acuity of patients with OCF was worse than that of patients without OCF (p<0.01). However, no statistical difference existed in the final visual acuity at 3 months after surgery (>0.05). Significant statistical difference of surgical efficacy existed between all the patients with OCF and without OCF (p<0.001).

CONCLUSIONS: Among patients with OCF, 20.9% were not detected by HRCT. Patients with OCF had a worse initial visual acuity than those without OCF. There was no significant difference in final visual acuity after ETOCD.