Despite extensive debate and publications in the management of blowout fracture (BOF), there are still considerable differences in the surgeons’ management of BOF due to a lack of reliable evidence-based studies. This article aimed to evaluate which BOF patients require surgical treatment due to functional and/or cosmetic deformities; evaluate which computed tomography (CT) scan findings predict these problems; and provide an algorithm in the management of BOF. Seventy-nine patients with BOF were treated conservatively and followed up prospectively regarding functional and cosmetic deformities for at least 1 year. The patients’ CT scans were analyzed and several measurements were performed. Patients’ symptoms and the clinical findings were correlated to the CT scan measurements. We found visible deformity in 37% of the patients, but only 10% chose to proceed to surgery due to cosmetic deformities. In patients with inferior BOF and a herniation < 1.0 mL, a visible deformity was found when the ratio between fracture and the fractured orbital wall areas was ≥42%, or the total area of the fracture was ≥ 2.3 cm2. In patients with inferior BOF and a herniation ≥ 1.0 mL, a visible deformity was found when the distance from the inferior orbital rim to the posterior edge of the fracture was ≥ 3.0 cm. In patients with inferomedial fracture, a visible deformity was found when the herniation was ≥ 0.9 mL. Diplopia improved significantly and remained in only 3% of the patients in nonoperated group. Hypoesthesia of the infraorbital nerve improved significantly, but 23% of the nonoperated and 50% of the operated patients still experienced loss of sensation at final control. In this prospective study, we found that not only herniated orbital volume but also other CT scan findings in BOF were crucial to predict late visible deformities. Based on these findings, we propose an algorithm for the prediction of late visible deformity with 83% accuracy. There are indications that diplopia without ocular motility disorder is due to edema and we recommend observation as long as the diplopia improves gradually.

To clarify the conflicting recommendations for care of blowout fracture (BOF), a prospective randomized study is required. Here, we present a prospective randomized pilot study on BOF. This article aimed to evaluate which computed tomography (CT) findings predict late functional and/or cosmetic symptoms in BOF patients with ≥ 1.0 mL herniation of orbital content into maxillary and/or ethmoidal sinuses. It also aimed to evaluate which patients with BOF would benefit from surgical treatment or observational follow-up. Twenty-six patients with BOF ≥ 1.0 mL herniation were randomized to observational ( = 10) or surgical treatments ( = 16) and were followed up for functional and cosmetic symptoms for at least 1 year. The results from CT scan measurements were correlated to the patients' symptoms and clinical findings which we report in this pilot study. Of the 10 patients randomized to observation, five had an inferomedial BOF with a herniation of ≥ 1.3 mL and all patients developed cosmetic deformities and required surgery. The remaining five patients in the observational group had inferior BOF and one of them had a distance of 3.3 cm from the inferior orbital rim to the posterior edge of the fracture and developed a cosmetic deformity but was unwilling to proceed to surgical treatment, and four patients had a median distance of 2.9 cm from the inferior orbital rim to the posterior edge of the fracture and did not develop cosmetic deformities. The median time from injury to surgery was 13 (3-17) days for the surgical group and 37 (17-170) days for the patients who underwent surgery in the observational group. The surgical results were similar for all the operated patients at the final control. Diplopia decreased and remained partly in one patient in the surgical group and in two patients in the observational group. Hypoesthesia of the infraorbital nerve decreased in nonsurgically treated patients, but surgery seemed to induce hypoesthesia. In this prospective randomized controlled pilot study on BOF, all patients in the observational group with inferomedial fractures developed visible deformity. Diplopia in BOF, without ocular motility limitation, is believed to be due to edema. Diplopia is not an indication for surgery as long as it reduces over time.