To evaluate the effect of orbital wall reconstruction with absorbable osteoconductive unsintered hydroxyapatite/poly L-lactide by assessment of the orbital volume via orbital computed tomography.

24 patients who followed up at least 6 months after orbital wall reconstruction with unsintered hydroxyapatite/poly L-lactide were included. Retrospective clinical chart reviews for clinical manifestations and complications were performed, and orbital volume measurements were taken using the Eclipse Treatment Planning System (ver.13.0, Varian Medical System Inc., Palo Alto, CA, USA) through orbital computed tomography, which were taken before operation, right after operation, and at last follow up.

Fourteen patients (58.3%) showed diplopia and extraocular muscle movement limitation preoperatively. Diplopia was resolved at last follow up and extraocular muscle movement limitation was improved at postoperative 6 months for all cases. The mean volumes of the fractured orbit and the unaffected orbit before operation were 23.62 ± 0.45 cm₃ and 21.95 ± 1.01 cm₃, respectively ( p = 0.003). The mean volumes of the fractured orbit and the unaffected orbit right after operation were 21.65 ± 0.91 cm₃ and 21.78 ± 0.83 cm₃, respectively ( p = 0.542). The mean volumes of the fractured orbit and the unaffected orbit at last follow up were 21.84 ± 0.93 cm₃ and 21.81 ± 0.91 cm₃, respectively ( p = 0.889).

Absorbable osteoconductive unsintered hydroxyapatite/poly L-lactide was effective for clinical improvement and orbital volume assessment in cases of orbital wall reconstruction and it can be used safely without definite implant related complications.