CLINICAL EFFICACY COMPARATIVE EVALUATION OF THE TREATMENT METHODS OF COMBINED DEFECTS AND DEFORMITIES OF THE ZIGOMA AND ORBIT

Abstract

Introduction. Zigoma and orbital defects still become an actual problem of maxilla-facial surgery due to limited possibilities to precise restoration of their complex anatomy. Functional unity of zigoma and orbit in aspects of eyeball support and protection increases requirements to reconstructive precision. The total and subtotal defects are the most difficult for reconstruction when traditional methods of reconstruction demonstrate unconvincing efficiency. Complex anatomy of zigoma and orbit, as combination of convexities, depressions limited an application of free or vascularised bone transplants for precise 3D restoration of the face. Facing this, new possibilities of reconstructed were developed, based on CAD/CAM technologies. Application of patient specific implants (PSI), designed according personal anatomy of the patient and manufactured by additive technologies, open new modalities to reconstruction in orthognatic surgery, cranioplasty and others, demonstrated promising results. So, these achievements and experience possible could be implemented for zigoma reconstruction. The aim of the study was to evaluate and compare clinical efficacy of zigoma and orbital defect treatment with traditional methods of reconstruction.
 Materials and methods. To reach this purpose, fifty-one patients, who underwent reconstruction procedures regarding zigoma defects, were enrolled to retrospective study. All of them were clinically examined before and after surgery. CT examination was performed before, 1 week and 1 year after surgery in all cases. The patients, included to the study, were divided on two groups – main and control, equal concerning age, sex and anatomical-topographic patterns of the defects. The main group consisted of 27 patients, who underwent zigoma reconstruction with PSI. The rest of the patients, treated with traditional approach (free or vascularised bone grafting, reconstructive plates or reconstruction with temporal muscle), were included to control group.
 Clinical efficacy was evaluated applying esthetical estimation of experts according to ranking scale. Additionally, frequency of complication and precision of reconstruction according to CT were analysed. Orbital volume differences were calculated for cases of orbital reconstruction.
 Results. Comparative analysis of esthetical results revealed higher quality of reconstruction in a main group. The patients did not require any further surgical procedures in 66,7% of cases, in contrast, in a control group additional interventions were indicated or performed in 85,3% of patients (p<0,05). Mean rate of aesthetic estimation by experts were 3,15+1,2 in main group and 1,96+0,8 in control. Follow-up period was longer than 12 months for both main and control groups. Mean follow-up were 20,4 ±9,3 and 26,2 ± 13,5 months respectively. During follow-up any kind of complications were observed between the patients of the main group in 14,8% of cases as well in control – 54,2 % (p=0,01). The main complication between the patients of first group was exposure of the implants, which was noted only in 3 cases, and was caused mainly extension of soft tissues above the implant or compromised soft tissue covering due to incomplete vascularisation of the flaps. At the same time the most frequently observed complications of the main group were total or partial resorption of the grafts (two cases), implant exposure (n=7) and limitation of mouth opening. Additionally, deformity of the fixators with bone fragment displacement was noted in 25,0 % cases.
 Eyeball displacement was defined in 66,7% of all cases. Mean volume difference in main group was 1,5±0,7 см3, when between patients of control it was 2,3±1,2см3 (р=0,032). The frequency of diplopia was equal for both group.
 Conclusions. The main advantage of PSI application for zigoma reconstruction is the possibility of the precise 3D restoration of its complex anatomy, renewal of the correct position of the zigoma. Relatively to the clinical tasks, PSI could be used as fixator or endoprosthesis separately or with bone graft procedures. In some clinical situations separate application of PSI as endoprosthesis may be consider as effective alternative for free tissue transfer procedures.