Abstract
Purpose
To determine the role of fracture size and soft tissue herniation as measured by computed tomography in predicting the development of persistent diplopia in patients with isolated orbital floor fractures.
Methods
A retrospective chart review identified patients presenting between March 2009 and 2012 with isolated orbital floor fractures. Computed tomographic scans were assessed for transverse fracture size and absence or presence of soft tissue herniation and rectus involvement. Presence of diplopia at 6–10 days, decision for surgical repair, and presence of diplopia were recorded.
Results
Fifty-six patients fulfilled inclusion criteria. Eighteen of 56 patients (32%) had preoperative diplopia. In Type A fractures, 0/9 (0%) small, 1/8 (12.5%) medium, and 2/14 (14%) large fractures had diplopia. For Type B fractures, 3/4 (75%) small, 9/13 (69%) medium, and 4/8 (50%) large fractures had diplopia. Type B fractures were significantly more likely to cause diplopia than Type A fractures in the small (p = 0.003) and medium (p = 0.007) size groups but not in the large groups (p = 0.07).
Conclusion
Transverse fracture size and presence of soft tissue herniation on CT imaging can predict development of persistent diplopia in isolated orbital floor fractures. Small and medium sized fractures with soft tissue herniation are more likely to cause diplopia than large sized fractures. We recommend early repair or closer observation of small and medium sized orbital floor fractures with soft tissue herniation due to the high risk of diplopia.
1
Introduction
Diplopia is arguably the most important complication of orbital floor fractures. During the first few days after injury, diplopia is often attributed to orbital edema and hemorrhage. Diplopia persisting beyond this period, however, is often attributed to soft tissue incarceration within the fracture site, and less commonly due to muscle or nerve injury . In the past, investigators have shown that direct involvement of the inferior rectus within the fracture site may increase the risk of persistent motility restriction . On the other hand, evidence that fibrous septa unite orbital tissue to the sheaths of the inferior rectus and oblique muscles suggests that any soft tissue incarceration within the fracture site may cause restriction .
Although it is generally agreed that larger fractures are at greater risk for enophthalmos, the relationship between fracture size and diplopia is less clear. Linear orbital floor fractures in young patients can result in significant motility restriction from entrapment of orbital tissue within the fracture site . Outside of this well known entity of a “trap-door” fracture, no studies have demonstrated a significant correlation between orbital floor fracture size and extraocular motility restriction.
The purpose of this study was to determine the role of fracture size and soft tissue herniation as measured by computed tomography in predicting the development of persistent diplopia in patients with isolated orbital floor fractures.
2
Methods
A chart review was conducted identifying all patients presenting to our practice between March 2009 and March 2012 with isolated orbital floor fractures. Exclusion criteria included additional orbital wall fractures, a previous history of decreased vision or strabismus, and lack of clinical data or appropriate follow-up. Computed tomography (CT) scans of all patients were assessed for transverse fracture size and absence (Type A) or presence (Type B) of significant soft tissue herniation with or without inferior rectus involvement. Soft tissue herniation was defined as any evidence of tissue seen below the bony fragments of the fracture site. Transverse fracture size was assessed using the ruler function on coronal CT scans. The distance from the medial to lateral edge of the fracture was measured on the coronal section showing the largest transverse extent of the fracture ( Fig. 1 ).
Fractures were divided into small (0–6 mm), medium (7–13 mm) and large (14–20 mm) groups. Clinical data were then collected including presence of preoperative diplopia at 6–10 days, timing and decision for surgical repair, and presence of diplopia and enophthalmos on last clinic visit. Only patients with at least 6 weeks of follow up after initial injury were included in our assessment of final post operative diplopia. By design, the study excluded any patient repaired within the first 5 days of injury due to extraocular muscle restriction causing oculocardiac reflex or vomiting. The Chi square test was used for statistical analysis between groups.
All data accumulation was carried out according to the guidelines of the Institutional Review Board (IRB) of Indiana University.
2
Methods
A chart review was conducted identifying all patients presenting to our practice between March 2009 and March 2012 with isolated orbital floor fractures. Exclusion criteria included additional orbital wall fractures, a previous history of decreased vision or strabismus, and lack of clinical data or appropriate follow-up. Computed tomography (CT) scans of all patients were assessed for transverse fracture size and absence (Type A) or presence (Type B) of significant soft tissue herniation with or without inferior rectus involvement. Soft tissue herniation was defined as any evidence of tissue seen below the bony fragments of the fracture site. Transverse fracture size was assessed using the ruler function on coronal CT scans. The distance from the medial to lateral edge of the fracture was measured on the coronal section showing the largest transverse extent of the fracture ( Fig. 1 ).
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