Volumetric Evaluated Bone Resorption After Open Reduction and Internal Fixation of Condylar Head Fractures of the Mandible.

PURPOSE: Decision making in the management of condylar head fractures remains difficult due to its dependency on multiple factors like fracture type, degree of dislocation, patient`s age and dental condition. As open reduction and internal fixation (ORIF) of condylar head fractures (CHFs) becomes more popular, the question of osteosynthesis removal is controversial. So far, information on volumetric changes after ORIF are available for a short-term period (<6 months) only. This study, therefore, was performed to assess bone resorption after condylar head fractures and to follow-up intermediate-term (>1 year) remodelling after removal of metallic osteosynthesis material. Furthermore clinical outcome was measured using Helkimo Index and put in relation with bone resorption. MATERIALS AND METHODS: A retrospective analysis of 19 patients who underwent open reduction and internal fixation of condylar head fractures at the University Hospital of Zürich between January 2016 and April 2018 using intraoperative cone-beam computed tomography repositioning control was conducted. The bone resorption on the condylar head was measured in the course after removal of osteosynthesis material by segmenting and superimposing of the postoperative 3D radiologic follow-up exam (T2) over the initial intraoperative cone-beam computed tomography (T1) using iPlan-CMF software. Complementary Helkimo index was assessed to put resorption rate in relation to clinical outcome. RESULTS: A total of 19 patients fulfilled the inclusion criteria. The mean follow-up time was 15.6 months and the mean bone resorption on the condylar head was -0.348cm3 or -15.29% of segmented condylar head. There was no correlation of clinical outcome and bone resorption. CONCLUSIONS: Helkimo index showed satisfying results; therefore, ORIF of condylar head fracture proves as a feasible treatment option. The mean bone resorption rate of -15.29% in the intermediate-term follow-up time (mean 15.6 months) is comparable to findings of other studies with short-term follow-up time (< 6 months). Thus, postinterventional remodeling activity and resorption seems highest in the first 4 to 6 postoperative months with little further resorption. In prevention of negative sequelae of protruding implants, timing of osteosynthesis material removal after this period of high bone remodeling activity is recommended. The resorption rate showed no correlation to clinical outcome.

Customized Titanium Reconstruction of Orbital Fractures Using a Mirroring Technique for Virtual Reconstruction and 3D Model Printing.

PURPOSE: Early operative reconstruction using titanium mesh is a technique often used for preventing sequelae after an orbital fracture. We sought to examine the utility of patient-specific molding of the mesh with a biomodel via virtual mirroring of the nonaffected side. METHODS: We retrospectively assessed the clinical and radiological outcomes of orbital fracture reconstruction using a customized titanium mesh shaped on 3D-printed biomodels in 34 unilateral orbital fracture cases. Preoperative virtual orbital reconstruction images, using the mirroring technique, were superimposed on postoperative 3D images, and clinical data from patient charts were analyzed. Orbital reconstructions were rated, and the intention to revise results intraoperatively, or during inpatient or outpatient phases, was assessed by 2 consultants and 2 residents. RESULTS: We found that most fractures arose from falls of <3 meters or from interpersonal violence. Ophthalmic injuries included subconjunctival bleeding, ocular contusion, enophthalmos, and diplopia. Long-term sequelae at last followup were diplopia (8.8%) and mild enophthalmos (11.8%). CONCLUSION: Interrater reliabilities regarding consultants' intention to revise results were substantial to almost perfect at any time point. Therefore, using the mirroring technique for the virtual reconstruction of a fractured orbit and a 3D-printed biomodel to customize commercial titanium implants yields good and reliable results, enhances surgical precision, and decreases the need for intraoperative revision, as well as long-term sequelae of orbital fractures.

Does Zygomatic Complex Symmetry Differ Between Healthy Individuals and Surgically Treated Patients Using Intraoperative 3-Dimensional Cone Beam Computed Tomographic Imaging?

PURPOSE: Reconstruction of symmetry after zygomaticomaxillary complex (ZMC) fractures is essential for esthetic appearance as well as function. Therefore, this study aimed to analyze whether bony facial symmetry in patients surgically treated for unilateral ZMC fractures via intraoperative imaging differs from that of healthy individuals. PATIENTS AND METHODS: Retrospective and cross-sectional radiographic measurements of patients treated for unilateral ZMC fractures via intraoperative cone beam computed tomography (CBCT) were performed to evaluate the postoperative ZMC symmetry. The same number of healthy individuals without any history of midfacial trauma matched for age and gender served as the control group. Asymmetry of the ZMC was determined by measuring bilateral differences in the malar eminence position on CBCT. In addition, demographic statistics, etiology, and fracture type were analyzed. RESULTS: Analysis of 57 surgically treated patients and 57 healthy individuals with a mean age of 29 years was performed. No significant difference in the symmetry of the malar eminence position was observed between healthy individuals and patients treated for a unilateral ZMC fracture (P = .890). In one third of patients, corrections were needed after intraoperative CBCT control. CONCLUSIONS: The results of this study indicate that, on average, a ZMC asymmetry of 1.6 mm is observed in healthy individuals. Furthermore, the use of intraoperative CBCT for the treatment of dislocated ZMC fractures helps to achieve precise anatomic, symmetrical repositioning and is suggested to improve the quality of care.

Improved Results in Closed Reduction of Zygomatic Arch Fractures by the Use of Intraoperative Cone-Beam Computed Tomography Imaging.

PURPOSE: The use of intraoperative imaging could help overcome the insufficiency of closed reduction that can result from the absence of visible feedback to evaluate the accuracy of the reduction in isolated zygomatic arch fractures. The aim of the present study was to evaluate the use of intraoperative 3-dimensional cone-beam computed tomography (CBCT) to improve the accuracy of reduction, by measuring the remaining cortical step and dislocation angle. We also evaluated the effect of CBCT on the need for repeat surgery. PATIENTS AND METHODS: We performed a retrospective cohort study of patients who had undergone zygomatic arch reduction surgery from January 2008 to May 2018. The patients were grouped according to the predictor variables into group A (postoperative radiologic follow-up studies) and group B (intraoperative CBCT imaging studies). The primary outcome variables were the remaining cortical step and dislocation angle compared with the ideal virtually mirrored position. These were assessed as measures of reduction accuracy. The secondary variables included age, gender, surgery duration, and fracture type. Statistical analysis was performed using a robust multiple regression analysis. RESULTS: The 45 patients were divided into 2 subgroups with 18 patients in the no intraoperative imaging (control) group and 27 patients in the intraoperative imaging group. Insufficient reduction occurred in 1 patient in the group without intraoperative imaging, leading to repeat surgery. No repeat surgery was necessary in the intraoperative imaging group. The remaining cortical step of the intraoperative imaging group was significantly lower than that of the control group (0.18 vs 2.03 mm; P < .001). For the remaining dislocation angle, similar findings were observed but without statistical significance (3.93° vs 7.75°; P = .58). CONCLUSIONS: The use of intraoperative CBCT significantly increased the accuracy of the reduction. Furthermore, the need for repeat surgery was not required for any patient in the intraoperative imaging group with CBCT-guided reduction.