Three-Dimensional Eyeball and Orbit Volume Modification After LeFort III Midface Distraction

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.

Prediction of exophthalmos by body mass index for craniofacial reconstruction: consequences for cold cases

It is inconvenient for a forensic practitioner to gather population-specific data before performing a facial reconstruction. The inconvenience may defeat the point of creating the reconstruction. The objective of this study was to evaluate a non-population-dependent method of determining exophthalmos. The protrusion of the eyeball is known to vary with the contents of the orbital cavity based on bony orbital resorption or increased or decreased fat contents, as well as according to relative eyeball size. Of use are available statistics on body mass index, and this is discussed within the context of eyeball protrusion. A weak positive correlation (0.3263) between the body mass index of the country where the study originated, and the degree of exophthalmos was found. The results suggest that eyeball protrusion rates can be established according to body mass index, and this framework may be more useful considering conventional police practices.

Orbital Reconstruction in Le Fort III Fractures

BACKGROUND

Few quantitative results are reported about the surgical effect of orbital reconstruction in Le Fort III fractures. The authors' team proposed an ordered surgery method which was effective for Le Fort III fractures. The aim of this study was to evaluate the effectiveness of this method with quantitative outcomes.

METHODS

A retrospective study was conducted of all patients who were diagnosed with Le Fort III fractures and underwent orbital and facial fractures repair from January 2015 to June 2019. Surgical reconstruction was performed with an ordered surgery method. Orbital volumes were used to evaluate the effectiveness of orbital reconstruction.

RESULTS

Fifteen patients (21 eyes) with Le Fort III fractures were included in this study. Preoperative and postoperative orbital volume changes were statistically significant ( P <0.01). For unilateral fractures, orbital volumes were different in 2 eyes ( P <0.01). For bilateral fractures, orbital volumes were almost the same in 2 eyes ( P =0.34). For the affected eye in unilateral fractures group and eyes in bilateral fractures group, after surgery, orbital volume were almost the same ( P =0.35).

CONCLUSIONS

This study showed effectiveness and safety of the ordered surgery in the treatment of Le Fort III fractures, which would result in significant decrease in orbital volumes.

Does different cranial suture synostosis influence orbit volume and morphology in Apert syndrome?

This study was performed to compare the orbital and peri-orbital morphological variations in Apert syndrome patients with different cranial vault suture synostosis, so as to provide an anatomic basis for individualized surgical planning. Computed tomography scans of 57 unoperated Apert syndrome patients and 59 controls were subgrouped as follows: type I, bilateral coronal synostosis; type II, pansynostosis; type III, perpendicular combinations of cranial vault suture synostoses. Orbit bony cavity volume was significantly reduced in type I and type II, by 19% (P < 0.001) and 24% (P < 0.001), respectively. However, the reduction of orbital cavity volume in type III did not reach statistical significance. Globe volume projection beyond the orbital rim, however, increased by 76% (P < 0.001) in type III, versus an increase of 54% (P < 0.001) in type I and 53% (P < 0.001) in type II, due to different ethmoid and sphenoid bone malformations. Maxillary bone volume was only significantly reduced in type I bicoronal synostosis (by 24%, P = 0.048). Both type I and type II developed relatively less zygoma and sphenoid bone volume. Different cranial vault suture synostoses have varied influence on peri-orbital development in Apert syndrome. Instead of mitigating the abnormalities resulting from bicoronal synostosis in type I, additional midline suture synostosis worsens the exorbitism due to a more misshaped ethmoid.

Characteristics of the Sphenoid Bone in Crouzon Syndrome

BACKGROUND

The goal of this study is to analyze the safety of reconstructive surgeries for Crouzon syndrome, and to understand the deformities and complications related to the surgical procedure.

METHODS

Thirty-nine subjects underwent preoperative computed tomographic scans were included (Crouzon, n = 19; controls, n = 20) in this study. Craniofacial cephalometric measurements were analyzed by Materialise software.

RESULTS

The overall average distance from the pterygoid junction to the coronal plane in the patients with Crouzon syndrome was 21.34 mm (standard deviation [SD] 5.13), which was deeper than that in the controls by 35% (P = 0.000).The overall average distances between the left and right foramen ovale and pterion on the sphenoid bone in the subjects were 64.93 mm (SD 7.56) and 67.83 mm (SD 8.57), which were increased by 13% (P = 0.001) and 14% (P = 0.001) compared with those in the controls.The overall distances between the most inferior point of the left and right lateral pterygoid plate and the medial pterygoid plate in the subjects were 51.09 mm (SD 6.68) and 51.51 mm (SD 10.98), which was not statically different from the controls (P = 0.887, P = 0.991, respectively).

CONCLUSIONS

This study characterized the surgically relevant anatomy of the sphenoidal bone. The pterygomaxillary junction is located in the posterior of the skull. Though there are some anatomical differences due to age, it is well known that the cranial cavity of the sphenoid side is likely to be enlarged in Crouzon syndrome, which may contribute to the other complications of the disease.

Retroposition of the Globe After Le Fort III Midfacial Distraction

BACKGROUND

Patients with syndromic craniosynostosis exhibit exorbitism due to supraorbital and midfacial retrusion. This study documented the change in sagittal orbital-globe relationship following Le Fort III midfacial advancement.

METHODS

This retrospective case series comprised patients with syndromic craniosynostosis who underwent midfacial distraction from 1997 to 2016. Changes in sagittal globe position in relation to the orbital rims were measured by pre- and postoperative direct anthropometry, computed tomographic scans, or both methods. Descriptive statistics were calculated; significance was set at P < 0.05.

RESULTS

Anthropometry showed a significant increase from superior orbital rim-to-corneal apex (os-acor) (4.1 ± 4.0 mm, P < 0.001) and from inferior orbital rim-to-corneal apex (oi-acor) (4.5 ± 5.3 mm, P < 0.001). The lateral orbital rim to the corneal apex (ol-acor) dimension did not change significantly. Computed tomography measurements confirmed retropositioned globes relative to the anterior border of the orbital cavity (2.5 ± 6.4 mm, P = 0.036). The 2 analytic methods yielded statistically similar results.

CONCLUSION

The globes move posteriorly a mean of 2.5 to 4.5 mm following Le Fort III midfacial distraction in patients with syndromic craniosynostosis. This finding is useful in attaining euophthalmos when planning and executing this procedure.

Is There a Difference in Orbital Volume Between Affected and Unaffected Sides in Patients With Unilateral Craniofacial Microsomia?

PURPOSE

Craniofacial microsomia (CFM) is characterized by malformations of structures derived from the first and second pharyngeal arches. The orbit is variably affected. The purpose of this study was to determine whether there is a difference in orbital volume between affected and unaffected sides in patients with unilateral CFM. The specific aims were to 1) measure orbital volume, 2) compare affected and unaffected sides, 3) evaluate the correlation between clinical evaluation of orbital size and volumetric measurement, and 4) determine whether there is a correlation between orbital volume and severity of mandibular deformity.

MATERIALS AND METHODS

This study is a retrospective case series of patients with unilateral CFM from Boston Children's Hospital (Boston, MA) who had a computed tomographic (CT) scan. Manual segmentation of the orbit using Mimics software (Materialise, Leuven, Belgium) was performed on CT images of the 2 orbits. The predictor variable was laterality (affected vs unaffected side) and the primary outcome variable was orbital volume. Wilcoxon signed rank test was used to compare these measurements and determine whether the affected side differed from the unaffected side. The correlation between orbital volume and Pruzansky-Kaban type of mandibular deformity, as documented in the medical record, was determined using the Spearman rank correlation coefficient.

RESULTS

Thirty-nine patients were included. Orbital volume was 10% smaller on the affected side (P = .001) in 80% of patients. There was no correlation between orbital size and severity of mandibular involvement.

CONCLUSION

The results of this study showed a marked difference in orbital volume between affected and unaffected sides in patients with unilateral CFM. These differences were small and might not be clinically relevant. Orbital volume did not correlate with severity of mandibular deformity.

Three-dimensional imaging of soft and hard facial tissues in patients with craniofacial syndromes: a systematic review of methodological quality

OBJECTIVES

To systematically review the methodological quality of three-dimensional imaging studies of patients with craniofacial syndromes and to propose recommendations for future research.

METHODS

PubMed, Embase and Cochrane databases as well as Grey literature were electronically searched. Inclusion criteria were patients with genetic syndromes with craniofacial manifestations and three-dimensional imaging of facial soft and/or hard tissues. Exclusion criteria consisted of non-syndromic conditions or conditions owing to environmental causes, injury or trauma, facial soft and hard tissues not included in the image analysis, case reports, reviews, opinion articles. No restrictions were made for patients' ethnicity nor age, publication language or publication date. Study quality was evaluated using the Methodological Index for Non-Randomized Studies (MINORS).

RESULTS

The search yielded 2228 citations of which 116 were assessed in detail and 60 were eventually included in this review. Studies showed a large heterogeneity in study design, sample size and patient age. An increase was observed in the amount of studies with time, and the imaging method most often used was CT. The most studied craniofacial syndromes were Treacher Collins, Crouzon and Apert syndrome. The articles could be divided into three main groups: diagnostic studies (34/60, 57%), evaluation of surgical outcomes (21/60, 35%) and evaluation of imaging techniques (5/60, 8%). For comparative studies, the median MINORS score was 13 (12-15, 25-75th percentile), and for non-comparative studies, the median MINORS score was 8 (7-9, 25-75th percentile).

CONCLUSIONS

The median MINORS scores were only 50 and 54% of the maximum scores and there was a lack of prospective, controlled trials with sufficiently large study groups. To improve the quality of future studies in this domain and given the low incidence of craniofacial syndromes, more prospective multicentre controlled trials should be set up.