Intraosseous Venous Malformation of the Zygomatic Bone: Comparison between Virtual Surgical Planning and Standard Surgery with Review of the Literature

Reconstruction of the orbitozygomatic framework: State of the art and perspectives

The reconstruction of the whole orbitozygomatic framework (OZF) is complex and can be encountered in cases of congenital midface deformity, after tumor ablative surgery and in severe facial trauma. Nowadays, surgeon has a wide range of available techniques that have continually grown over the past years, optimizing the surgical management and the aesthetical outcomes. Among them, the autologous bone graft (ABG) remains one of the most suitable options : ABG is easy to harvest and has optimal biological properties for bone healing. It can be tailored to the patient anatomy thanks to the recent advances in computer-assisted surgery. However, substantial drawbacks remain such as the early resorption of the non-vascularized graft, the need of a donor site and its potential morbidity. Alloplastic reconstruction is another option that can resolve both the resorption issue and the donor site morbidity. Moreover, the 3D-printing technologies also allows the manufacturing of patient specific implants. However, alloplastic materials have a variable success, especially due to the high risk of infection or exposure. Consequently, regenerative medicine is a promising field that aims to find a procedure without the disadvantages of ABG or alloplastic based reconstructions, but displaying similar or even higher success rate. Indeed, recent tissue engineering strategies have demonstrated encouraging results for bone regeneration using natural or synthetic biomaterials, patient cells and synthetic bioactive substances. The objective of this review is to present the etiologies of OZF defect, the available reconstruction procedures as well as the current state of the research.

Guided Genioplasty: Comparison between Conventional Technique and Customized Guided Surgery

BACKGROUND

Genioplasty as an isolated surgical technique is a highly demanded procedure in the maxillofacial surgery area. Advances in facial reconstructive surgery have been associated with less morbidity and more predictable results. In this paper, "conventional" genioplasty and genioplasty by means of virtual surgical planning (VSP), CAD-CAM cutting guides, and patient custom-made plates are compared.

METHODS

A descriptive observational study was designed and implemented, and 43 patients were treated, differentiating two groups according to the technique: 18 patients were treated by conventional surgery, and 25 patients were treated through virtual surgical planning (VSP), CAD-CAM cutting guides, STL models, and titanium patient-specific plates.

RESULTS

The operation time ranged from 35 to 107 min. The mean operative time in the conventional group was 60.06 + 3.74 min.; in the custom treatment group it was 42.24 + 1.29 min (p < 0.001). The difference between planned and obtained chin changes in cases of advancement or retrusion was not statistically significant (p = 0.125; p = 0.216). In cases of chin rotation due to asymmetry, guided and personalized surgery was superior to conventional surgery (p < 0.01). The mean hospital stay was equal in both groups. A decrease in surgical complications was observed in the group undergoing VSP and customized treatment.

CONCLUSIONS

Multi-stage implementation of VSP with CAD-CAM cutting guides, STL models, and patient-specific plates increased the accuracy of the genioplasty surgery, particularly in cases of chin asymmetry, reducing operation time and potential complications.

Manufacturing Polymer Model of Anatomical Structures with Increased Accuracy Using CAx and AM Systems for Planning Orthopedic Procedures

Currently, medicine uses typical industrial structure techniques, including reverse engineering, data processing, 3D-CAD modeling, 3D printing, and coordinate measurement techniques. Taking this into account, one can notice the applications of procedures used in the aviation or automotive industries based on the structure of Industry 4.0 in the planning of operations and the production of medical models with high geometric accuracy. The procedure presented in the publication shortens the processing time of tomographic data and increases the reconstruction accuracy within the hip and knee joints. The procedure allows for the partial removal of metallic artifacts from the diagnostic image. Additionally, numerical models of anatomical structures, implants, and bone cement were developed in more detail by averaging the values of local segmentation thresholds. Before the model manufacturing process, additional tests of the PLA material were conducted in terms of its strength and thermal properties. Their goal was to select the appropriate type of PLA material for manufacturing models of anatomical structures. The numerical models were divided into parts before being manufactured using the Fused Filament Fabrication technique. The use of the modifier made it possible to change the density, type of filling, number of counters, and the type of supporting structure. These treatments allowed us to reduce costs and production time and increase the accuracy of the printout. The accuracy of the manufactured model geometry was verified using the MCA-II measuring arm with the MMDx100 laser head and surface roughness using a 3D Talyscan 150 profilometer. Using the procedure, a decrease in geometric deviations and amplitude parameters of the surface roughness were noticed. The models based on the presented approach allowed for detailed and meticulous treatment planning.