Late reconstruction of the complex orbital fractures with computer-aided design and computer-aided manufacturing technique.

BACKGROUND: To construct three-dimensional (3D) imaging and computer generated models of complex orbital fractures, and develop a Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM) system to help improve the surgical planning of complex orbital fracture and promote its outcome.

METHODS: A prospective study was carried out on 17 patients with unilateral complex orbital fractures from Mar 2003 to Mar 2006 at the Shanghai ninth people's hospital. The utilization of a CAD/CAM technique based on Helical computer tomography data, with stereolithographical (SLA) modelling as intermediate step, enabled surgeons to plan for the surgical progress of osteotomy, movement, reposition, fixation and material implanting. Orbital volume was calculated pre and post-operatively. Orbital fracture reconstruction and globe repositioning was performed and followed up 3-9 months post-treatment. Ocular function and aesthetic deformities such as enophthalmos, diplopia and extraocular motility problems were accessed. The data was processed with SAS 6.17 statistical software.

RESULTS: 17 patients with complex orbital fractures underwent successful orbital fracture reconstruction surgery. The deformities of orbit, medial canthus, nose, zygomata, maxillary and frontal bone were well corrected. The volume of reconstructed orbit was approximately symmetrical with respect to the contralateral orbit. Enophthalmos was corrected and diplopia, extraocular movement were improved.

CONCLUSIONS: CAD/CAM system enables the surgeon to predict reconstructive surgical steps before the operation, and can help to improve the outcome of surgery. This technique may be proved as one of the most useful clinical tools for orbital surgery.