Introduction:

Restoration of normal orbital volume and globe position following traumatic injury is often difficult. Intraoperative navigation has emerged as a tool to allow the visualization of the implant position intraoperatively, by means of the planification in the preoperative computed-tomographic scan (CT scan).

Objectives:

The aim of this study was to compare the postoperative changes in orbital volume between two groups of study: one group that underwent surgical intervention before the implementation of intraoperative navigation (control group), and other group of patients which had undergone surgery with the aid of a navigation system (Software iPlan CMF version 3.0.5, Brainlab(r), Feldkirchen, Germany) (navigation group). Another endpoint of our study was to determine it the presurgical planification and intraoperative navigation aided to position the implant. For that purpose, we determined the implant position with respect to the orbital floor and medial orbital wall and compared it between both groups of study. As secondary endpoints, we compared the rate of postoperative outcomes and reintervention rate between both groups.

Materials and methods:

A retrospective cohort study was designed. We selected a total of 35 consecutive orbital operations for unilateral orbital fractures performed between 2015 and 2018 at the Department of Oral and Maxillofacial Surgery in La Paz Hospital (Madrid), Spain. We collected information regarding: demographic data, cause of the fracture, time elapsed between diagnosis and surgical treatment, symptoms at diagnosis (diplopia, globe projection, ocular motility impairment), radiological findings (affected wall, muscular entrapment, herniation of the periorbital structures), and outcomes after surgical treatment (diplopia, globe position, ocular motility impairment, reintervention). By means of the iPlan CMF software, the orbital volume was determined in the preoperativeand postoperative CT scan. The plate position was determined by measuring the distance between the plate and the orbital rim, the distance between the plate and the residual posterior intact bony ledge and the distance between the plate and the medial orbital wall. Measurements were performed automatically in the three planes of space, although we used the sagital plane to measure the distance between the plate and the orbital rim and between the plate and the residual posterior intact bony ledge. To measure the distance between the plate and the medial orbital wall we used the axial plane.

Results:

After surgery, we observed that abnormal globe position was significatively less frequent in the navigation group than in the control group (p = 0.029). The reoperation rate was 11 % in the navigation group and 35% in the control group (p = 0.071). Mean orbital volume of the unaffected orbit was 29.32 ± 2.64 cm3 in the navigation group and 28.64 ± 2.68 cm3 in the control group. Mean orbital volume of the affected orbit was 34.19 ± 3.67 cm3 in the navigation group and 32.78 ± 3.09 cm3 in the control group. Mean reconstructed orbital volume was 29.47 ± 2.75 cm3 in the navigation group and 28.88 ± 3.72 cm3 in the control group. Mean volume reduction and the mean difference in volume between unaffected and reconstructed side did not show significative differences between both groups. The mean distance from plate to orbital floor at the residual posterior intact bony ledge showed significative differences (p = 0.001), being inferior in the navigation group.

Conclusions:

The use of intraoperative navigation in orbital fractures is effective in improving plate positioning in the residual posterior intact bony ledge of the floor of the orbit, reducing complications such as enophthalmos compared to conventional surgery. Furthermore, the use of intraoperative navigation seems to decrease the rate of reintervention compared to conventional surgery. The restoration of orbital volume seems to be well addressed by both methods.

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