Accuracy of intraoperative navigation for orbital fracture repair: A retrospective morphometric analysis.

In this retrospective case series, patients undergoing surgery to treat isolated orbital floor fractures were morphometrically analyzed. Cloud Compare was used to compare mesh positioning with a virtual plan, using the distance-to-nearest-neighbor method. To assess the accuracy of mesh positioning, a mesh area percentage (MAP) parameter was introduced and three distance ranges were defined as the outcome measures: the 'high-accuracy range' included MAPs at a distance of 0-1 mm from the preoperative plan; the 'intermediate-accuracy range' included MAPs at a distance of 1.1-2 mm from the preoperative plan; the 'low-accuracy range' included MAPs at a distance of >2 mm from the preoperative plan. To complete the study, morphometric analysis of the results was combined with clinical judgment ('excellent', 'good', or 'poor') of mesh positioning by two independent blind observers. In total, 73 of 137 orbital fractures met the inclusion criteria. In the 'high-accuracy range' the mean, minimum, and maximum MAP values were 64%, 22%, and 90%, respectively. In the 'intermediate-accuracy range', the mean, minimum, and maximum values were 24%, 10%, and 42%, respectively. In the 'low-accuracy range', the values were 12%, 1%, and 48%, respectively. Both observers classified 24 cases of mesh positioning as 'excellent', 34 as 'good', and 12 as 'poor'. Within the limitations of the study, it seems that virtual surgical planning and intraoperative navigation has the potential to add quality to the repair of the orbital floor and, therefore, should be taken into consideration whenever appropriate.

Virtual planning and CAD/CAM-assisted distraction for maxillary hypoplasia in cleft lip and palate patients: Accuracy evaluation and clinical outcome.

The aim of this prospective study was to report the experience with a specific guided distraction protocol for the treatment of CLP patients with severe midface hypoplasia. From January 2016 to April 2019, six consecutive, non-growing, CLP patients with maxillary hypoplasia underwent a specific distraction protocol based on the use of VSP, CAD/CAM-generated surgical splints, cutting guides, prebent internal maxillary distractors, early removal of distractors, and acute callus manipulation and fixation. STL files for VSP, using multislice CT scans taken preoperatively (T0) and 3 months after distractor removal (T1) were superimposed using the free software 3D Slicer and Geomagic Wrap to evaluate the accuracy of maxillary repositioning and assess 3D bone changes. Clinical outcome was evaluated at the 1-year follow-up (T2). The patients and surgeon were satisfied with the occlusal and aesthetic outcomes. A maximum difference of 2 mm between the VSP and the actual surgical outcome was chosen as the success criterion for accuracy. The average linear difference for selected points was <2 mm in four patients and >2 mm in two patients. The average distance of the postoperative maxilla from the VSP model was 2.28 mm (median 1.85), while the average forward movement of the maxilla was 10.18 mm The protocol used is effective and accurate in the correction of severe maxillary hypoplasia in CLP patients. Early removal of the distractor and stabilization with plates reduces patient discomfort and does not jeopardize stability. This protocol should be reserved for complex cases due to the costs of the procedure, which are not negligible.

The Shape of Things to Come: In-Hospital Three-Dimensional Printing for Mandibular Reconstruction Using Fibula Free Flap.

OBJECTIVES/HYPOTHESIS: The aim of this study was to explore whether the production of in-hospital, low-cost surgical cutting guides would be possible and to assess different cutting guide shapes to facilitate the surgery and the application with instruments. STUDY DESIGN: Cohort study. METHODS: Using free computer-aided design software, surgical cutting guides for the mandible and fibula were designed and used to perform virtual segmental osteotomies and fibula transplants in seven patients. RESULTS: Fourteen virtual osteotomies were performed using the free software and the proposed workflow. Thirteen guides were then printed to transfer the virtual planning information to the operating room. CONCLUSIONS: Virtual planning and the three-dimensional (3D) printing of guides for mandibular reconstruction is reliable with the aid of an in-hospital 3D laboratory. We also demonstrated that different guides with different shapes could be produced with benefits during surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 2020.