Evaluating The Prebent Titanium Mesh for Zygomatico-Orbital Reconstruction in Twelve Patients Measuring Multiple Ophthalmologic Parameters, Aesthetic Results, Orbital Volume, Area of Bone Defect, Layout Angle, Gab Length and The Accuracy of Reconstruction

The Role of Prebent Titanium Mesh With 3D-Printed Model in Reconstruction of Zygomatico-Orbital Fractures

Purpose: The aim of this study was to evaluate the role of using a prebent titanium mesh on a 3D-printed model as an intraoperative guide to reconstruct orbito-zygomatic-maxillary complex (OZMC) fractures.

Subjects and method: This is a prospective, interventional, longitudinal, single armed case series study that was carried out on twelve patients with unilateral displaced orbito-zygomatico-maxillary complex (OZMC) fracture indicated for orbital floor reconstruction as evidenced by clinical and radiographic examination. Open reduction and internal fixation were utilized to treat those fractures, patients were collected from the department of Oral and Maxillofacial surgery, Faculty of Dentistry, Tanta University. Post-operative evaluation: all patients underwent regular follow up for six months. The following parameters were evaluated: visual acuity, external appearance of the eye including hypoglobus and enophthalmos, diplopia, ocular motility, the aesthetic results, orbital volume, area of bone defect, layout angle, gab length and the zygomatic reconstruction.

This study was conducted on twelve patients with unilateral displaced OZMC fracture indicated for orbital floor reconstruction as evidenced by clinical and radiographic examination. The patients' ages ranged from 18-55 years old. All patients were evaluated preoperatively for collecting demographic data, taking general medical, surgical, and dental history and for determining the main patient's chief complaints and postoperative expectations. Approval for this project was obtained from Research Ethics Committee (REC) of faculty of Dentistry, Tanta University. The purpose of the present study was explained to the patients and informed consents were obtained according to the guidelines of human research adopted by the REC at Faculty of Dentistry, Tanta University. After obtaining the preoperative CT scan, 3D simulation was performed using (3Diagnosys, version 4.2, 3diemme. Como, Italy) as the following steps:

1. Importing CT DICOM images.
2. Mirror image of the normal side.
3. Segmentation to remove any unwanted areas.
4. Thresholding to choose the density of bone.
5. Conversion to STL format.
6. Exporting as an STL file to the 3D printer. The 3D printer (Upbox, Tiertime, Korea) was used to print the patient specific model. The Printing material was ABS/PLA. The technology used for the printing process was FDM (Fused Deposition Modeling), where a filament is heated above 200 degrees and extruded through a nozzle of 0.4 mm diameter to print layer by layer with a resolution of 100 microns. Routine preoperative investigations (complete blood picture, prothrombin test, liver &renal function test and viral profile) were done for all patients, together with relevant medical consultation when required. The patients were operated under general anesthesia via nasal endotracheal intubation. The surgical site was disinfected using Povidone-iodine then isolated and draped with sterile dressing. Reconstruction was done carefully. All outcome measures were measured later on, and adequate statistical analysis was performed.

Inclusion Criteria:

1. Patients with unilateral displaced zygomatico-orbital fracture (with fractured orbital floor).
2. Patients with no previous history of orbital reconstruction.
3. Diplopia within 30° of primary gaze.
4. Radiological evidence of extraocular muscle entrapment and/or positive forced duction test.
5. Enophthalmos of more than 2mm.

Exclusion Criteria:

1. Bilateral zygomatico-orbital fractures.
2. Rupture of the globe.
3. Hyphema.
4. Retinal detachment.
5. Traumatic optic nerve lesions.