Classification of orbital fractures using the AO/ASIF system in a population surveillance cohort of traumatic optic neuropathy.
OBJECTIVE
In our prospective nationwide surveillance study of traumatic optic neuropathy (TON) in the United Kingdom, the prevalence of orbital fractures was found to be 39% (47/121). The prevalence of skull fractures was 7.4% (9/121). This study aims to identify the association of craniofacial-orbital fractures with the severity of visual loss.


METHODS
TON patients who sustained orbital fractures were identified prospectively by population-based active surveillance through the British Ophthalmic Surveillance Unit over a 2-year period. Available CT scans were classified by a head and neck radiologist according to the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) scheme: the face was divided into 4 units; fractures in each unit were graded according to displacement (A-C) and severity (1.1-3.3). Correlation between severity of craniofacial orbital fractures and visual acuity as well as number of fractured units and visual acuity were evaluated.


RESULTS
Twelve of the 25 patients (48%) with imaging available had adequate high resolution craniofacial CT imaging for review and classification using the AO/ASIF system (i.e. 48 classifiable units). Three of 48 (6%) units were undisplaced (grade A), 18 of 48 (29%) units were minimally displaced (grade B), and 4 of 48 (8%) units had largely displaced (grade C) fractures. Twenty-three units (47.9%) had no fractures; 5 patients had radiological evidence of optic canal fractures. Poor visual acuities positively correlated with severity of fractures graded using the AO/ASIF classification (Spearman's rho = 0.95, p = 0.05) and number of fractured units (Spearman's rho = 1.0, p < 0.0001).


CONCLUSIONS
AO/ASIF classification system provides a uniform method in the assessment of orbital fractures which correlates with visual outcome in TON.
Central Eye Services, Central Middlesex Hospital, North West London Hospitals NHS Trust , London NW10 7NS , United Kingdom and.
Hon Shing
HS
Ong
Dania
D
Qatarneh
Rebecca L
RL
Ford
Ravi Kumar
RK
Lingam
Vickie
V
Lee
D000293:Adolescent; D000328:Adult; D005147:Facial Bones / Q000293:injuries*; D005593:Fracture Fixation, Internal; D006801:Humans; D009915:Orbit / Q000293:injuries*; D009917:Orbital Fractures / Q000145:classification* / Q000000981:diagnostic imaging / Q000601:surgery; D011159:Population Surveillance; D011446:Prospective Studies; D012887:Skull Fractures / Q000145:classification* / Q000000981:diagnostic imaging / Q000601:surgery; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D006113:United Kingdom; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
Classification; orbital fracture; prognosis; radiology; traumatic optic neuropathy