The orbit first! A novel surgical treatment protocol for secondary orbitozygomatic reconstruction

A novel surgical treatment sequence for secondary orbitozygomatic complex (OZC) reconstruction is described. Orbital reconstruction is performed before OZC repositioning. A surgical plan is made: the affected OZC is virtually osteotomized and aligned with a mirrored model of the unaffected OZC. A patient-specific implant (PSI) is designed for orbital reconstruction. Screw holes from the primary reconstruction are used for fixation. Primary screw hole positions at the repositioned OZC are embedded in the design, to guide OZC repositioning. A second patient-specific design is made for guidance at the zygomaticomaxillary buttress.

The workflow was utilized in two patients. The PSI was positioned using navigation feedback. After repositioning of the zygomatic complex, the screw hole positions at the infraorbital rim and zygomaticomaxillary buttress seemed to align perfectly: no screw hole adjustments were necessary. Minor deviations were seen between planned and acquired PSI position; the mean errors between planned and acquired OZC position were 1.5 and 1.2 mm.

Orbital reconstruction with a PSI before OZC repositioning ensures true-to-original orbital reconstruction. The use of old screw hole positions enables the PSI to be used as a static guide for OZC repositioning. The combination of static and dynamic guidance increases predictability in secondary OZC reconstruction.