Determining orbital volumes of sheep, goats and gazelles via computed tomography.

BACKGROUND: Orbital volume refers to the sum of bulbus oculi volume and orbital cavity volume. Scientists use orbital volume as a guide to diagnose, treat and prognose various eye diseases such as thyroid eye disease and enophthalmos. OBJECTIVE: This study aims to examine the orbital volumes of sheep, goats and gazelles to demonstrate homotypic variations and interspecific differences between them. METHODS: Crania of six male tuj sheep, five male hair goats and five male gazelle were used in this study. The crania were scanned using a 64-detector multi-detector computed tomography with a slice thickness of 0.625 mm at 80 kV, 200 MA and 639 mGy. The cross-sectional images were stored in DICOM format and then transferred to MIMICS 20.1 software. Afterwards, models were made by establishing the orbital borders on the cross-sections. Volume values were calculated based on the models. RESULTS AND CONCLUSION: No homotypic variation was found between the right and left volumes within the species (p > 0.05). A statistically significant difference was observed in terms of interspecific right and left orbital volumes between sheep and gazelles (p < 0.05). It was concluded that the orbital parameters of the sheep, goats and gazelles in the same family help reveal their differences in the visual anatomy of these species and provide reference data for clinical diagnosis, treatment and the prognosis follow-up of ocular diseases in animals.

The impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures.

PURPOSE: The orbital floor is frequently involved in head trauma. Current evidence on the use of reconstruction materials for orbital floor repair is inconclusive. Accordingly, this study aimed to compare the impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures. METHODS: Standardized isolated orbital floor fractures were symmetrically created in 11 cadaver heads that provided 22 orbits. PDS foils with thicknesses of 0.25-0.5 mm were inserted. Computed tomography (CT) scans of the native, fractured, and reconstructed orbits were obtained, and orbital volume, orbital height, and foil bending were measured. RESULTS: Orbital volume and height significantly (p < 0.01) increased after the creation of isolated orbital floor fractures and significantly (p = 0.001) decreased with overcorrection of the orbital geometry after orbital floor reconstruction with PDS 0.25 mm or PDS 0.5 mm. The orbital geometry reconstruction rate did not differ significantly with respect to foil thickness. However, compared to PDS 0.5 mm, the use of PDS 0.25 mm resulted in quantitatively higher reconstructive accuracy and a restored orbital volume that did not significantly differ from the initial volume. CONCLUSION: Orbital floors subjected to isolated fractures were successfully reconstructed using PDS regardless of foil thickness, with overcorrection of the orbital geometry. Due to its lower flexural stiffness, PDS 0.25 mm appeared to provide more accurate orbital geometry reconstruction than PDS 0.5 mm, although no significant difference in reconstructive accuracy between PDS 0.25 mm and PDS 0.5 mm was observed in this cadaveric study.

Classical Orbital Floor Post-Traumatic Reconstruction vs. Customized Reconstruction with the Support of "In-House" 3D-Printed Models: A Retrospective Study with an Analysis of Volumetric Measurement.

BACKGROUND: Orbital floor fractures (OFFs) represent an interesting chapter in maxillofacial surgery, and one of the main challenges in orbit reconstruction is shaping and cutting the precise contour of the implants due to its complex anatomy. OBJECTIVE: The aim of the retrospective study was to demonstrate, through pre- and postoperative volumetric measurements of the orbit, how the use of a preformed titanium mesh based on the stereolithographic model produced with 3D printers ("In-House" reconstruction) provides a better reconstruction volumetric compared to the intraoperatively shaped titanium mesh. MATERIALS AND METHODS: The patients with OFF enrolled in this study were divided into two groups according to the inclusion criteria. In Group 1 (G1), patients surgically treated for OFF were divided into two subgroups: G1a, patients undergoing orbital floor reconstruction with an intraoperatively shaped mesh, and G1b, patients undergoing orbital floor reconstruction with a preoperative mesh shaped on a 3D-printed stereolithographic model. Group 2 (G2) consisted of patients treated for other traumatic pathologies (mandible fractures and middle face fractures not involving orbit). Pre- and postoperative orbital volumetric measurements were performed on both G1 and G2. The patients of both groups were subjected to the measurement of orbital volume using Osirix software (Pixmeo SARL, CH-1233 Bernex, Switzerland) on the new CT examination. Both descriptive (using central tendency indices such as mean and range) and regressive (using the Bravais-Pearson index, calculated using the GraphPad program) statistical analyses were performed on the recorded data. RESULTS: From 1 January 2017 to 31 December 2021, of the 176 patients treated for OFF at the "Magna Graecia" University Hospital of Catanzaro 10 fulfilled the study's inclusion criteria: 5 were assigned to G1a and 5 to G1b, with a total of 30 volumetric measurements. In G2, we included 10 patients, with a total of 20 volumetric measurements. From the volumetric measurements and statistical analysis carried out, it emerged that the average of the volumetric differences of the healthy orbits was ±0.6351 cm3, the standard deviation of the volumetric differences was ±0.3383, and the relationship between the treated orbit and the healthy orbit was linear; therefore, the treated orbital volumes tend to approach the healthy ones after surgical treatment. CONCLUSION: This study demonstrates that if the volume is restored within the range of the standardized mean, the diplopia is completely recovered already after surgery or after one month. For orbital volumes that do not fall within this range, functional recovery could occur within 6 months or be lacking. The restoration of the orbital volume using pre-modeled networks on the patient's anatomical model, printed internally in 3D, allows for more accurate reconstructions of the orbital floor in less time, with clinical advantages also in terms of surgical timing.

Are Age and Trauma Mechanism Associated with Volume Change in the Fractures of the Bony Orbit?

Blowout fractures are common midfacial fractures in which one or several of the bones of orbital vault break. This is usually caused by a direct trauma to the eye with a blunt object such as a fist. Fracturing of the fragile orbital bones can lead to changes in the orbital volume, which may cause enophthalmos, diplopia, and impaired facial aesthetics. Objectives: The aim of this study is to investigate whether there is an association between volume change of the bony orbit and age, gender, or trauma mechanism. Methods: A retrospective study of patients with unilateral blowout or blow-in fractures treated and examined in Päijät-Häme Central Hospital, Lahti, Finland was conducted. Altogether, 127 patients met the inclusion criteria. Their computed tomographs (CT) were measured with an orbit-specific automated segmentation-based volume measurement tool, and the relative orbital volume change between fractured and intact orbital vault was calculated. Thereafter, a statistical analysis was performed. A p-value less than 0.05 was considered significant. Results: We found that relative increase in orbital volume and age have a statistically significant association (p = 0.022). Trauma mechanism and gender showed no significant role. Conclusions: Patient's age is associated with increased volume change in fractures of the bony orbit.

Contemporary Treatment of Silent Sinus Syndrome: A Case Report and Literature Review.

Silent sinus syndrome is a rare clinical entity affecting the maxillary sinus, characterized by ipsilateral enophthalmos and hypoglobus. Its etiology and pathophysiology are still debated. It is diagnosed by clinical examination and confirmed with computed tomography. It is commonly managed surgically. We present the case of a 34-year-old woman with silent sinus syndrome treated with a patient-specific implant for orbital reconstruction, functional endoscopic sinus surgery approach, intraoperative scan, and surgical navigation, successfully restoring orbital volume and sinus ventilation.

Automated 3-D Computer-Aided Measurement of the Bony Orbit: Evaluation of Correlations among Volume, Depth, and Surface Area.

(1)The study aimed to measure the depth, volume, and surface area of the intact human orbit by applying an automated method of CT segmentation and to evaluate correlations among depth, volume, and surface area. Additionally, the relative increases in volume and surface area in proportion to the diagonal of the orbit were assessed. (2) CT data from 174 patients were analyzed. A ball-shaped mesh consisting of tetrahedral elements was inserted inside orbits until it encountered the bony boundaries. Orbital volume, area depth, and their correlations were measured. For the validation, an ICC was used. (3) The differences between genders were significant (p < 10-7) but there were no differences between sides. When comparing orbit from larger to smaller, a paired sample t-test indicated a significant difference in groups (p < 10-10). A simple linear model (Volume~1 + Gender + Depth + Gender:Depth) revealed that only depth had a significant effect on volume (p < 10-19). The ICCs were 1.0. (4) Orbital volume, depth, and surface area measurements based on an automated CT segmentation algorithm demonstrated high repeatability and reliability. Male orbits were always larger on average by 14%. There were no differences between the sides. The volume and surface area ratio did not differ between genders and was approximately 0.75.

Matrixmidface Preformed Orbital Implants for Three-Dimensional Reconstruction of Orbital Floor and Medial Wall Fractures: A Prospective Clinical Study.

Study Design: Prospective Interventional study. Objective: To evaluate the efficiency of Matrixmidface preformed Orbital plates for three-dimensional reconstruction of orbital floor and medial wall fractures. Methods: This prospective institutional clinical study was conducted on a group of 14 patients who underwent repair of orbital floor and medial wall fracture defects using Matrixmidface Preformed Orbital plates and open reduction and internal fixation of associated fractures. The following parameters were studied preoperative and postoperative enophthalmos, hypoglobus, orbital volume; correction of diplopia, intraoperative and postoperative complications. Results: All 14 patients were males aged between 19 and 42 years. The most common mode of injury was found to be road traffic accidents (RTAs) followed by self-fall and trauma at workplace. Orbital fractures were associated with other concomitant maxillofacial fractures in 12 patients (85.7%) while 2 patients (14.3%) had pure blowout fractures. Significant improvement of enophthalmos was noted from preoperative period to 1 week, 6 weeks, and 6 months postoperatively (P value .02, .01, and .01, respectively). Out of 11 patients with preoperative hypoglobus, 5 patients (45.45%) had persistent hypoglobus in the immediate postoperative period which reduced to 4 patients (36.36%) at 6 weeks postoperatively (p value .00). The postoperative orbital volume of fractured side ranged from 20.3 cm3 to 26.76 cm3 with a mean of 23.50 cm3 ± 1.74. The mean difference between the volumes of the repaired and uninjured sides was found to be .27 cm3 ± .39 (P value .02) denoting that the reconstruction of the orbit closely approximated that of the uninjured side. Conclusions: The Matrixmidface Preformed Orbital plate provides exceptional reconstruction of the orbital blowout fracture defects and ensures satisfactory results clinically and radiographically. The plate ensures an approximate recreation of topographical anatomy of the orbit and adequately restores the orbital volume. It provides adequate correction of asymmetry, hypoglobus, enophthalmos and attempts to restore eye movements, without causing any significant postoperative complication.

Measuring orbital Volume Using Open Source Software and its Application in Orbitozygomatic Fractures.

Study Design: Technical note. Objective: Changes in orbital volume can lead to esthetic and functional complications of the orbit. In this article, the procedure to calculate the orbital volume using the open source software Aliza 3D DICOM is described. Methods: This article describes the steps to use this novel software. To validate the software, the normal orbital volume was calculated bilaterally on CT scans with normal orbital anatomy. The volumes of unilateral orbitozygomatic fracture cases were compared. Results: This open source software has easy access. The normal orbital volume calculated using this software was 24.4 cc ± 0.72. In the unilateral orbitozygomatic fracture cases, an increased orbital volume was calculated. Conclusions: This easy access, inexpensive, and convenient computer aided software can be used to calculate orbital volume facilitating treatment plan for correction of the orbit volume.

Insights into Orbital Symmetry: A Comprehensive Retrospective Study of 372 Computed Tomography Scans.

Background: The operation planning and production of individualized implants with the help of AI-based software after orbital fractures have become increasingly important in recent years. This retrospective study aimed to investigate the healthy orbitae of 372 patients from CT images in the bone and soft tissue windows using the Disior™ Bonelogic™ CMF Orbital software. (version 2.1.28). Methods: We analyzed the variables orbital volume, length, and area as a function of age and gender and compared bone and soft tissue windows. Results: For all variables, the intraclass correlation showed excellent agreement between the bone and soft tissue windows (p < 0.001). All variables showed higher values when calculated based on bone fenestration with, on average, 1 mL more volume, 0.35 mm more length, and 0.71 cm2 more area (p < 0.001). Across all age groups, men displayed higher values than women with, on average, 8.1 mL larger volume, a 4.78 mm longer orbit, and an 8.5 cm2 larger orbital area (p < 0.001). There was also a non-significant trend in all variables and both sexes toward growth with increasing age. Conclusions: These results mean that, due to the symmetry of the orbits in both the bone and soft tissue windows, the healthy orbit can be mirrored for surgical planning in the event of a fracture.

Orbital Development in Children with Retinoblastoma: An Imaging-Based Study.

PURPOSE: To examine whether children treated for Retinoblastoma (Rb) have impaired orbital development. METHODS: A retrospective case series was performed among children with Rb treated at a single medical center from 2004 to 2020. Orbital volumes and measurements were assessed by 3-dimensional image processing software. The main outcome measures were differences in orbital growth between Rb and non-Rb eyes assessed at last follow-up. RESULTS: Among 44 patients included (mean age 16.09 ± 18.01 months), a positive correlation between age and orbital volume was observed only in the uninvolved, healthy eyes (p = .03). In unilateral cases, orbital growth in the horizontal, vertical, and depth planes was smaller on the affected side compared to the healthy eyes (p < .05). Orbits that underwent enucleation showed decreased growth over time compared to those treated conservatively (p = .017). CONCLUSIONS: Orbital growth rate is slower in the orbits of children treated for Rb compared to healthy orbits. Enucleation negatively affects orbital growth.

Evaluation of changes in orbital volume in adult female patients with maxillary transverse deficiency treated with a maxillary skeletal expander.

OBJECTIVES: The effects of using a maxillary skeletal expander (MSE) on the orbital volume and width between periorbital bones in the treatment of adult female patients with maxillary transverse deficiency (MTD) were evalua⁃ted. METHODS: A total of 20 adult female patients with MTD with an average age of (22.60±6.29) years were included in the study. The patients were treated with MSE. Cone beam computed tomography was performed before expansion (T0) and no more than 3 weeks after expansion (T1). Orbital volume and periorbital bone width were measured with Mimics 21.0 and analyzed with SPSS 20.0. Paired t-test was performed, and a P value of <0.05 indicated significant difference. RESULTS: After expansion, the orbital volume increased by (346.80±275.31) mm3 (P<0.05). The width between the right and left zygomaticomaxillary sutures increased by (1.69±0.57) mm (P<0.05), and the width between the right and left infraorbital points increased by (1.71±0.70) mm (P<0.05). However, the width between the right and left frontozygomatic sutures increased by (0.15±0.32) mm (P>0.05). Finally, the width between the right and left supraorbital points increased by (0.23±0.52) mm (P>0.05). CONCLUSIONS: The maxillary skeletal expander slightly expanded the orbital volume in the adult female patients and increased the lateral widths of the periorbital bones.