Virtual surgery simulation in orbital wall reconstruction: integration of surgical navigation and stereolithographic models

Abstract

Purpose: Correction of post traumatic orbital and zygomatic deformity is a challenge for maxillofacial surgeons. Integration of different technologies, such as software planning, surgical navigation and stereolithographic models, opens new horizons in terms of the surgeons' ability to tailor reconstruction to individual patients. The purpose of this study was to analyze surgical results, in order to verify the suitability, effectiveness and reproducibility of this new protocol.

Methods: Eleven patients were included in the study. Inclusion criteria were: unilateral orbital pathology; associated diplopia and enophthalmos or exophthalmos, and zygomatic deformities. Syndromic patients were excluded. Pre-surgical planning was performed with iPlan 3.0 CMF software and we used Vector Vision II (BrainLab, Feldkirchen, Germany) for surgical navigation. We used 1:1 skull stereolithographic models for all the patients. Orbital reconstructions were performed with a titanium orbital mesh. The results refer to: correction of the deformities, exophthalmos, enophthalmos and diplopia; correspondence between reconstruction mesh positioning and preoperative planning mirroring; and the difference between the reconstructed orbital volume and the healthy orbital volume.

Results: Correspondence between the post-operative reconstruction mesh position and the presurgical virtual planning has an average margin of error of less than 1.3 mm. In terms of en- and exophthalmos corrections, we have always had an adequate clinical outcome with a significant change in the projection of the eyeball. In all cases treated, there was a complete resolution of diplopia. The calculation of orbital volume highlighted that the volume of the reconstructed orbit, in most cases, was equal to the healthy orbital volume, with a positive or negative variation of less than 1 cm(3).

Conclusion: The proposed protocol incorporates all the latest technologies to plan the virtual reconstruction surgery in detail. The results obtained from our experience are very encouraging and lead us to pursue this path.

Keywords: Enophthalmos; Orbital volume; Orbital wall reconstruction; Stereolithographic models; Surgical navigation.