In- Versus Out-Fracture: A Novel Concept in Naso-Orbito-Ethmoid Injury.

Study design: A retrospective study.

Objective: The Markowitz-Manson classification system categorizes nasoorbitoethmoid (NOE) fractures by severity of injury and remaining integrity of the medial canthal tendon. However, this system does not account for direction of bony displacement (in-fracture vs out-fracture), which can greatly affect symptomatology and management. We hypothesize that NOE fractures will present differently based upon their severity: Type I injuries are likely to present with medial nasal bone displacement (in-fracture), whereas Type III fractures will be more prone to lateral displacement (out-fracture).

Methods: A retrospective review was performed for all patients with NOE fractures who were evaluated by the plastic surgery department at a level 1 trauma center over a 6-year period. Computed tomography data were evaluated to assess for directionality of fracture segment displacement. Frequencies of medial, lateral, and non-displacement across NOE types were compared by Chi-Squared Goodness of Fit and Fisher's Exact Tests.

Results: 111 patients met inclusion criteria. The patient population was 73.9% male and averaged 51.2 years old. When bilateral fractures were counted independently, there were 141 cases in total: 115 Type I, 20 Type II, and 6 Type III. Type I fractures were most commonly in-fractured (48.7%), while Type III injuries were consistently out-fractured (100%) (p < .001).

Conclusions: While Type II and III NOE fractures have dominated clinical focus, this study highlights the prevalence of impaction within Type I fractures. These findings advocate for a more comprehensive approach to the evaluation of Type I NOE fractures and their potential risks, including traumatic hypotelorism and nasal airway obstruction.