Functional outcome after non-surgical management of orbital fractures--the bias of decision-making according to size of defect: critical review of 48 patients.

The treatment of mild and moderate fractures of the orbital wall is controversial. Apart from clinical signs, the size of the defect is often used to aid the decision about treatment. We hypothesised that variables would be present that had an impact on the position and motility of the globe but were independent of the size of the defect, and prevented a balanced judgement of the outcome of conservative treatment. Between January 2000 and December 2007, 48 of 127 patients were included in this retrospective study to analyse the functional outcome of orbital fractures managed without operation. Selection was dependent on the availability of complete clinical records, post-traumatic computed tomographic (CT) scans (axial and coronal sections) and ophthalmic examination. All 48 defects were analysed and allocated to categories of a semiquantitative classification. The area of fracture of each defect was calculated with an integral calculus or geometrical formula and correlated with the associated category. Category A included all orbital walls as a single unit (A1) and combined fracture patterns (A2 and higher). Category B described isolated fractures of the medial wall. There was a significant correlation between classes A1 and A2 (p<0.01) and absolute area of the fracture (0.98 (0.4)cm(2) and 2.42 (0.8)cm(2)). Diplopia was most often seen in fractures in category B1 (the anterior third of the medial wall) and the post-traumatic position of the globe significantly correlated with the area of the fracture (p=0.04). The degree of diplopia was less severe in fractures of the posterior portion of the orbit (zones 2 and 3) compared with fractures of the anterior orbit, even if the defect was larger. The conservative management of category A1-3 and B1-3 fractures up to 2.42 (3.15)cm(2) showed no functional impairment, provided that enophthalmos was less than 2mm and there was no entrapment of periorbital tissue or extraocular muscles. We found good correlation between enopthalmos and the size of the fracture, but not for diplopia or motility of the eye. We conclude that conservative management of an orbital fracture in which the defect is less than 3cm(2) has a low risk of permanent functional damage if enophthalmos is less than 2mm and entrapment of soft tissue or muscles is excluded.