Patient-specific Virtual Planning Leads To Superior Symmetry For Late Post-traumatic Deformity After Orbital Zygomatic Maxillary Complex Fractures

Purpose: Post-traumatic deformity after Orbital-ZMC facial fractures is notoriously difficult to correct because of soft tissue contraction and loss of anatomic landmarks. Patient-specific virtual planning (VSP) has been successfully used in head and neck reconstruction and orthognathic surgery. In order to study whether VSP was also beneficial in post-traumatic orbital-malar deformity correction, we studied comparative groups for volumetric symmetry and patient satisfaction. Methods: Post-traumatic Orbital-ZMC deformity patients with displaced, healed zygomatic maxillary complex (ZMC) and orbital floor fractures were divided into 2 equal, consecutive groups: 1) No Virtual Planning (intraoperative on-table attempt to reposition ZMC based on contralateral malar projection-the 'eyeball test') and 2) Virtual Planning (3D CT scan mirrored-image ZMC repositioning with cutting guides and custom plates) over a 12-year period (n=32). Surgery involved complete soft tissue release and repositioning of ZMC based on 'eyeball test' or mirrored position; in addition, the orbital floor was reconstructed with an implant. Outcomes were compared using 1) Orbital volume, 2) Globe position, 3) Malar projection, and 4) Volumetric comparison (3D scanning at 6 months). For Patient satisfaction, Patient-Reported Outcomes Measurement Information System (PROMIS) surveys were used for psychosocial indicator assessment. Results: Groups were comparable: age (38.2 + 5years vs 36.8 + 4years), mechanism of injury (fall/motor vehicle collision/assault: 35/28/37% vs 31/33/36%), time from injury to reconstruction (4.2 + 3years vs 3.8 + 2years), and follow-up duration (13.1 + 4months vs 12.7 + 2months). Orbital volume: The traditional group had greater variability in postoperative orbital volume symmetry, indicating less predictable volume restoration; this was also true for globe position (centrum). Malar projection: Postoperative deviation from the ideal malar coordinate (based on the contralateral side) was more accurate with the VSP group (deviation of 1.6 mm compared to 4.3 mm). Volume: Both improved in malar volume symmetry. The Traditional group improved from 87.1% to 98.2%, while the VSP group improved from 88.5% to 102.2%; however, VSP had lower variability postoperatively (greater predictability). Psychosocial Indicators (PROMIS scores) were superior with Virtual Planning (3D mirrored-image): Anxiety (56.5+6.6 vs. 61.2+8.6), Depression (54.6+7.6 vs. 59.7+9.4), Meaning and Purpose (57.6+7.6 vs. 53.7+9.4), but were variable with other indicators. Conclusions: For post-traumatic facial deformity after zygomatic maxillary complex and orbital floor fracture, Virtual Planning (3D mirrored-image) had superior consistent outcomes with regard to orbital and malar symmetry compared to No Virtual Planning (eyeball test).