Surgical Planning: Facial Reconstruction

Quick case summary

Pre-operational planning of maxillofacial surgery has been quite a challenge due to the fact that the collection of algorithms necessary to achieve the desired outcome vastly differ from what e.g. a total joint arthroplasty usually requires. For example, volumetric measures to assure symmetry, mesh-operations to separate all vertices and edges that correspond to an octant of the axis-aligned bounding box, etc. come to mind.
Thankfully, after about half a dozen cases, the set of geometrical tools needed for operations like this slowly became more and more defined and clear with time.

This particular patient had a missing left side mandible resulting in facial asymmetry and a total misalignment (top half of the image). To restore the anatomically correct alignment, the mandible had to be segmented separately for an in-place rotational correction, and - after removing metal artifacts - the intact side of the mandible had to be mirrored to visualize the "curve" to be recreated. The missing part of the body and the ramus itself have been replaced by segments of the patient's fibula. The resulting model is shown in the bottom half.

To make sure the technician could create each patient specific cutting guide - there were no digitally created guide models for this case due to (mainly) time constraints - the segments had to be measured and visualized from relevant sides, so the jawline to be recreated would be precise.

The necessary resections had to be documented precisely for the surgeon also, to have a complete picture of the dimensions and the angular relationship between the bone segments.

All parts, and the total assembly(!) of the resulting plan as well, have been 3-D printed.