Surgical timing and quantitative functional outcomes in orbital trapdoor fractures with extraocular muscle incarceration.

PURPOSE: To investigate the influence of surgical timing using quantitative Hess area ratio (HAR%) and binocular single vision (BSV) assessments. METHODS: This retrospective study included patients with pure orbital floor trapdoor fractures associated with EOM incarceration. Clinical characteristics, surgical timing, Hess chart findings, and BSV measurements were reviewed. Cases were classified into an early (≤ 2 days after injury) and delayed surgery groups (> 2 days after injury). The delayed group was further subdivided into mildly delayed (2-4 days) and markedly delayed (> 4 days) subgroups. RESULTS: Thirty-six patients (mean age, 12.7 ± 9.7 years) were included in the final analysis. The inferior rectus muscle was the most commonly incarcerated EOM (28 cases). HAR% improved significantly from 31.6 ± 19.2% preoperatively to 91.5 ± 12.2% postoperatively (P < 0.001), while BSV% improved from 8.2 ± 19.0% to 79.9 ± 16.4% (P < 0.001). The proportion of patients with oculocardiac reflex symptoms was significantly higher in the early surgery group (P = 0.012). Postoperative HAR% was significantly lower in the markedly delayed group than in the early surgery group (P = 0.036). Patients undergoing earlier surgical intervention tended to demonstrate better binocular visual outcomes. CONCLUSIONS: Urgent surgical repair for orbital floor trapdoor fractures with EOM incarceration tended to result in favorable postoperative functional outcomes. Surgical intervention within 2 days after injury was associated with better postoperative ocular motility recovery, whereas marked surgical delay (> 4 days after injury) may negatively affect functional outcomes.