Inferior oblique muscle branch incarceration in orbital floor trapdoor fractures: Clinical characteristics and the impact of surgical timing.

Using a retrospective observational study design, we enrolled consecutive patients with unilateral orbital floor trapdoor fractures involving incarceration of orbital fat and the inferior oblique muscle branch (IOMB) of the oculomotor nerve who were treated at the Aichi Medical University Hospital over a 12.5-year period to evaluate the impact of surgical timing on postoperative functional recovery. The primary predictor variable was the interval from injury to surgery, categorized as 0-7, 8-14, or >14 days. The primary outcome variables were the postoperative Hess area ratio (HAR%) and binocular single vision (BSV%). Descriptive and bivariate statistical analyses were performed, and a P-value <0.05 was considered statistically significant. The final cohort comprised 70 patients (24.3% female) with a mean age at injury of 13.4 ± 6.6 years (range, 1-42 years). Surgical intervention significantly improved the mean HAR% from 66.2 ± 16.9 to 95.8 ± 6.9% (P<0.001) and mean BSV% from 42.5 ± 27.7 to 81.1 ± 17.1% (P<0.001). No significant differences in postoperative HAR% or BSV% were observed among the early, intermediate, and delayed surgery groups (P>0.05). These findings indicate that surgical repair of orbital floor trapdoor fractures involving the IOMB yields favorable functional outcomes irrespective of the timing of surgery.