Page 77 - Advanced concepts in orbital wall fractures

Discussion
Computer-assisted surgery (CAS) has proved to be a valuable tool in
trauma surgery3,22-24. The first two steps in CAS are: 1. three-dimensional
(3D) advanced diagnostics and 2. preoperative virtual planning of the
orbital reconstruction. Both steps offer many possibilities. Advanced
diagnostics grant the surgeon the opportunity to conduct a volumetric
analysis, mirror the unaffected side, analyse the size, and extent of the
fracture in comparison to several landmarks and measure angulations25.
This is followed by virtual surgery to determine implant size and position
and to use this as a virtual guidance during surgery. The aim of this
study was to determine the importance of these steps by comparing C two reconstruction groups: with and without the use of preoperative 4 planning. The main objective was to evaluate the effect of preoperative
planning without navigation on the accuracy and predictability of implant positioning.
The results demonstrate that the use of a 3D software planning tool in orbital floor and medial wall fractures improves the accuracy of implant positioning. A significant improvement in the absolute implant position is achieved for translation, roll, and yaw in comparison to the control group. The ideal implant position was compared with respect to the boundaries of the fracture, the inferior orbital rim, and the transition zone from the orbital floor to the medial wall. These additional anatomical landmarks seemed to be helpful during insertion and positioning of the implant. As shown in the results these extra landmarks are beneficial in defining the optimal position. The pitch demonstrates an improvement, but not significantly. Pitch is determined by the support of the inferior orbital rim and the posterior ledge. In most cases, these are intact, and thus there is limited variation in positioning of the implant due to the vertical support. In both groups, no implant was placed below the posterior ledge. Changes in antero-posterior placement or yaw and roll may change pitch slightly due to the curvature of the orbit. Due to these circumstances, the average difference in pitch was small for both groups, and therefore it was likely that the improvement would not be significant.
Preoperative planning
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