Prevalence of Pediatric Orbital Roof Fractures as a Function of Orbital Dimensions

Purpose: Orbital roof fractures are more likely to occur in younger children, specifically less than 7 years of age.[1] [2] It has been well stated that cranium-to-face ratio decreases with age.[2] In addition, development and pneumatization of sinuses relates to the increased incidence of orbital roof fractures in children less than 7 years of age.[3] [4] We propose a novel idea that length of the orbital roof is a representative of the neuro cranium and length of the orbital floor is a representative of midface. The purpose of this study is to examine if simple measurements of orbital dimensions as defined above are correlated with rates of orbital roof fractures within the pediatric population.

Methods: A retrospective review of maxillofacial and orbital imaging was performed from October 1, 2011 to October 31, 2014 at a major pediatric trauma center. Patients with orbital roof fractures were identified. Patients were stratified into two groups by age <7 and >/= 7. Images were reviewed, and the lengths of the orbital roof (superior orbital rim to anterior clinoid process) and orbital floor (inferior orbital rim to anterior clinoid process) were measured for each patient using McKesson imaging software by the primary author (SCD) (Fig. 1). Statistical analysis was performed using a student t-test with significance determined by p < 0.05. The main outcome measures were the ratio of orbital roof length to floor length compared with age.

Results: Sixty-six patients with orbital roof fractures were identified. There were 40 males and 26 females. Patient ages ranged from 2 months to 17 years. 31 patients were younger than 7 years and 35 patients were 7 years or older. Mean orbital roof length was 43.4mm, standard deviation 3.06 mm and 45.1 mm, standard deviation 3.94 mm for patients <7 and ≥7, respectively (p = 0.023). Mean orbital floor length was 41.3 mm, standard deviation 2.99 mm and 47.7 mm, standard deviation 4.19 mm for patients <7 and ≥7 respectively (p < 0.00001; Fig. 2). The mean roof to floor ratio (RTFR) for patients <7 was 1.051, standard deviation 0.039 and for patients ≥ 7 was 0.947, standard deviation 0.031 (p < 0.00001).

Conclusion: As children age, the relative length of the orbital roof decreases when compared with the length of the orbital floor. The RTFR was greater than 1.0 in children younger than seven. These differences were statistically significant when compared with children 7 and older. This may help explain the differences noted in orbital fracture patterns between early and late childhood described in previous studies.[1] [2] [3] [4]

Fig. 1

Fig. 2

• References

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• <edb> 3 Kozak FK, Ospina JC, Cardenas MF. Characteristics of Normal and Abnormal Postnatal Craniofacial Growth and Development. In: Flint PW. , ed. Cummings Otolaryngology. 6th ed. Philadelpha: Saunders; 2015: 2865-2890
• Messinger A, Radkowski MA, Greenwald MJ, Pensler JM. Orbital roof fractures in the pediatric population. Plast Reconstr Surg 1989; 84 (02) 213-216 , discussion 217–218