A surgical instrument to improve implant positioning in orbital reconstruction: a feasibility study

Abstract Adequate positioning of an orbital implant during orbital reconstruction surgery is mandatory for restoration of the pre-traumatised anatomy, but visual appraisal of the implant’s position is limited by the keyhole access and protruding soft-tissues. A positioning instrument, that attaches to the implant, was designed to provide feedback outside the orbit. The goal of this study was to evaluate the effect on implant positioning accuracy of the instrument workflow compared to visual appraisal. Ten orbits in five human cadaver heads were reconstructed twice: once using visual appraisal and once using the instrument workflow. No significant improvement was found for the roll (5.8 vs 3.4 degrees respectively, p = 0.16), pitch (2.1 vs 1.5, p = 0.56) or translation (2.9 vs 3.3, p = 0.77). The yaw, was significantly reduced if the instrument workflow was used (15.3 vs 2.9, p = 0.02). The workflow is associated with low cost and low logistical demands, and may prevent outliers in implant position in a clinical setting where intra-operative navigation or patient-specific implants are not available.