Increase In Orbital Volume Research Articles

Orbital aspects following monobloc advancement in syndromic craniosynostosis

The monobloc advancement with distraction is a treatment modality for syndromic craniosynostosis, to correct exorbitism, upper airway compromise and malocclusion. In this report orbital volume and movements of (peri-)orbital structures and globes of seven patients following monobloc distraction are evaluated. In preoperative and postoperative CT-scans orbital volume was assessed and a 3D coordinate system with eleven landmarks was used to measure the movements of orbital structures and globes and to measure the change of exorbitism. Correlation between orbital volume, movements of the orbital structures and change in exorbitism was studied. The orbital volume increased by 49.9% (left) and 50.4% (right). The average anterior movement of the bone was 13.6 mm (left) and 13.9 mm (right). The mean anterior movement of the left globe was 5.8 mm and of the right globe 5.3 mm. The ratio of globe/bone movement was 0.4. Exorbitism decreased with 7.8 mm (left) and 8.1 mm (right). Differences between left and right for orbital volume, for movements and for the decrease in exorbitism were not significant. Volume enlargement and decrease in exorbitism were correlated (p ≤ 0.05). Following monobloc advancement orbital volume increases, (peri-)orbital structures and the globe move forward and exorbitism diminishes.

Radiologic and Long-Term Clinical Outcome From Treatment of Isolated Medial Orbital Wall Blowout Fractures

Blowout fractures in the medial orbital wall may lead to enophthalmos, ocular dysmotility, and diplopia. Ten consecutive patients with unilateral, isolated fractures of the medial orbital wall were retrospectively studied. The radiologic accuracy of the medial orbital wall reconstructions and the long-term clinical outcomes were assessed. All cases were treated through a bicoronal approach and by use of porous polyethylene-titanium implants. The total fracture area and the orbital volume increase from the blowout were measured on computed tomographic scans. Next, we evaluated the reconstruction in the posterior part of the medial wall. This was done by calculating the ratio between the defect area and the implant area located behind the anterior ethmoidal canal. The patients were examined at least 1 year after the operation, and the rates of enophthalmos and diplopia were evaluated. The mean fracture defect area was 2.45 cm2 (range, 0.41-4.16 cm2), and the mean volume increase from the blowout fractures was 1.82 cm3 (range, 0.53-2.76 cm3). The orbital volume was accurately restored in all patients. However, the ratio of implant to defect area behind the anterior ethmoidal canal ranged from 0% to 100% (mean, 47.3%). None of the patients had enophthalmos or diplopia at the long-term follow-up. The results confirm that restoration of orbital volume is important to prevent postoperative enophthalmos in isolated medial orbital blowout fractures. Complete reconstruction of the most posterior part of the medial orbital wall seems to be of lesser importance.

Orbital change following Le Fort III advancement in syndromic craniosynostosis: Quantitative evaluation of orbital volume, infra-orbital rim and globe position

Patients with syndromic craniosynostosis suffering from shallow orbits due to midface hypoplasia can be treated with a Le Fort III advancement osteotomy. This study evaluates the influence of Le Fort III advancement on orbital volume, position of the infra-orbital rim and globe.In pre- and post-operative CT-scans of 18 syndromic craniosynostosis patients, segmentation of the left and right orbit was performed and the infra-orbital rim and globe were marked. By superimposing the pre- and post-operative scans and by creating a reference coordinate system, movements of the infra-orbital rim and globe were assessed.Orbital volume increased significantly, by 27.2% for the left and 28.4% for the right orbit. Significant anterior movements of the left infra-orbital rim of 12.0mm (SD 4.2) and right infra-orbital rim of 12.8mm (SD 4.9) were demonstrated. Significant medial movements of 1.7mm (SD 2.2) of the left globe and 1.5mm (SD 1.9) of the right globe were demonstrated. There was a significant correlation between anterior infra-orbital rim movement and the increase in orbital volume.Significant orbital volume increase has been demonstrated following Le Fort III advancement. The position of the infra-orbital rim was moved forward significantly, whereas the globe position remained relatively unaffected.

Clinical Implications of Orbital Volume Change in the Management of Isolated and Zygomaticomaxillary Complex–Associated Orbital Floor Injuries

Orbital floor injuries can occur in isolation or in association with zygomaticomaxillary complex fractures. Volumetric computed tomographic measurements of affected orbits are investigated for utility in guiding management in these two groups. The medical records of all patients with craniomaxillofacial injuries (2003 to 2005) were reviewed. Of 522 total patients, 45 patients had isolated orbital floor fractures, 13 of whom underwent repair (29 percent), and 64 had zygomaticomaxillary complex fractures, 36 of whom underwent reconstruction (56 percent) and 10 of whom underwent orbital floor repair (16 percent). Radiographic criteria for floor exploration included 50 percent area fracture in isolated injuries and 10-mm estimated zygomaticomaxillary complex compression in zygomaticomaxillary complex-associated floor injuries. Volume measurements of the affected orbits were obtained and compared with the uninjured contralateral orbit. Before treatment in the operative zygomaticomaxillary complex group, there was an average decrease in orbital volume of 18.3 percent. In the isolated orbital floor group, there was an average increase in orbital volume of 28.3 percent. Zygomaticomaxillary complex-associated orbital floor injuries can be compressive injuries associated with loss of volume, whereas isolated injuries generally result in volume expansion. Radiographic criteria are often considered in the decision to proceed with orbital floor exploration to avoid late enophthalmos. The literature suggests that a 20 percent change in orbital volume results in perceptible deformity. Therefore, a radiographic criterion of 50 percent floor area (28 percent volume increase) in isolated injuries may be too stringent; an estimated 10 mm of compression (18.3 percent volume change) is a reasonable operative criterion for floor exploration in zygomaticomaxillary complex-associated injuries.

Anatomical Changes of the Ethmoid Cavity After Endoscopic Sinus Surgery

Alteration of the bony architecture of the sinus cavities has been observed in chronic sinusitis. Plasticity of the ethmoid sinus framework after endoscopic surgery, however, is a newly described entity. The objective of this study was to determine the incidence and extent of changes in ethmoid size after ethmoidectomy. Retrospective review performed at an academic medical center. Computed tomography scans performed from 2006 through 2007 at the Massachusetts Eye and Ear Infirmary (n = 5,131) were reviewed to identify 100 consecutive patients who underwent sinus surgery and met inclusion criteria. Seven dimensions were measured for each pre- and postoperative scan (n = 200) using Voxar 3D software. Computed tomography scans performed before and 2 to 37 months after ethmoidectomy demonstrated a decrease of 1.1 +/- 1.6 mm in mean ethmoid cavity width at the level of the cribriform plate and posterior globe after surgery (P < .0001). Twenty-five patients (25%) had >1 mm decrease in mean ethmoid width, and six patients (6%) had a decrease of >2 mm (mean 3.1 +/- 0.9 mm). These findings seemed to be the result of postoperative bowing of the medial ethmoid walls with a corresponding increase in orbital volume. These volumetric changes resulted in a postoperative subclinical retrodisplacement (enophthalmos) of the globes (mean 0.2 +/- 0.8 mm, P = .008). The extent of surgery, including performance of frontal recess dissection (P = .007) and total ethmoidectomy (P = .021) were found to be independent predictors of the observed changes in sinus dimensions. Postsurgical plasticity of the ethmoid cavity is a new concept supported by observed changes in sinus dimensions after ethmoidectomy. These changes may reflect a loss of internal structural support and forces of contracture during the postoperative healing period.

Choice of proper time for orbital implant in anophthalmia children

From birth to adulthood, craniofacial development is dependent on the normal orbital growth. The increase of orbital volume is related to the growth of eyeball. Debates are ongoing as to when should be the appropriate age to remove abnormal globes and place orbital implants before puberty. Some articles suggested that the earlier to place of orbital implants the better, however, some considered that static orbital implants make invalid for stimulating the bony orbit to a full-developed volume, which will result in more than once implantation procedures. This article will focus on the growth of the orbit and the eyeball, retard of orbital development caused by soft tissue absence, as well as the selection of proper time for the placement of orbital implants during childhood.

Correction of Superior Sulcus Deformity and Enophthalmos with Porous High-density Polyethylene Sheet in Anophthalmic Patients

Superior sulcus deformity is the main cosmetic problem in anophthalmic patients. Many methods of correcting enophthalmos have been reported, especially in patients with orbital wall fracture. The purpose of this study is to review the long term results of effectiveness in superior sulcus deformity correction by subperiosteal Medpor sheet implantation in anophthalmic patients. Subperiosteal Medpor sheets were used in 11 eyes of 11 anophthalmic patients. To estimate the effectiveness, photographs were taken and exophthalmometric value with their own prosthesis using Hertel exophthalmometer was measured in all patients before and after surgery. The overall cosmetic results in superior sulcus deformity were 'excellent' in 3 (27.3%), 'good' in 6 (54.5%), 'fair' in 2 (18.2%). The overall results in enophthalmos were 'excellent' in 3 (27.2%), 'markedly improved' in 4 (36.4%), 'slightly improved' in 4 (36.4%). Most patients had a marked increase in orbital volume, except two patients. They received irradiation treatment in early childhood so showed unsatisfactory results in both superior sulcus deformity and enophthalmos. Subperiosteal Medpor sheet implantation is considered to be a reliable and safe procedure without serious complication and with an excellent cosmetic result.

Status of the internal orbit after reduction of zygomaticomaxillary complex fractures

Purpose We sought to determine the status of the internal orbit before and after reduction of zygomaticomaxillary complex (ZMC) fractures when treated without internal orbital reconstruction. Patients and methods We conducted a retrospective study of preoperative and postoperative computed tomography (CT) scans in 65 patients with unilateral ZMC fractures who were treated by reduction of the ZMC complex without internal orbital reconstruction. The size and location of the internal orbital defects, orbital soft tissue displacement, and orbital volume were assessed in the preoperative and postoperative CT scans. Results Reduction in the ZMC fractures was considered ideal in 58 of the 65 patients. Only minor malpositions occurred in the remaining 7 patients. The size of the internal orbital defects increased slightly with ZMC reduction but the internal orbital fractures were realigned, and few had increases in orbital volume or soft tissue sagging into the sinuses. Examination of follow-up CT scans in several patients taken weeks to months later showed that the residual defects became smaller and that none of these patients had an increase in orbital volume or soft tissue sagging. Conclusion The preoperative CT scan can be used to assess the amount of internal orbital disruption for purposes of developing a treatment plan in patients with ZMC fractures. When there is minimal or no soft tissue herniation and minimal disruption of the internal orbit, ZMC reduction is adequate treatment.

"Balanced" orbital decompression for severe Graves' orbitopathy: technique with treatment algorithm.

Graves' orbitopathy can produce proptosis, compressive optic neuropathy, and extraocular motility abnormalities; symptoms result from an increase in orbital volume due to expansion of intraorbital fat, with or without extraocular muscle involvement. We conducted a chart review of patients who underwent orbital decompression to treat Graves' orbitopathy. Twenty-two orbits (13 patients) underwent orbital bone decompression, of which 17 orbits (9 patients) underwent the combined medial and lateral "balanced" decompression. All patients had significant improvement with an average decrease in proptosis of 5.9 mm in the balanced decompression group. Restoration of normal optic nerve function was achieved in all patients with compressive optic neuropathy. Diplopia was noted in 4 patients (30.7%) preoperatively. Two patients had new postoperative diplopia (15.35%). In our experience, "balanced" decompression results in a reduction of proptosis and improved optic nerve function and has a low incidence of complications.

Computer-Assisted Secondary Reconstruction of Unilateral Posttraumatic Orbital Deformity

Until now, computer-assisted surgery has not been practiced as part of the surgical routine of posttraumatic orbital reconstruction. The purpose of this study was to investigate the use of a navigation system for computerassisted preoperative planning with virtual reconstruction to obtain symmetry of the orbits and intraoperative control of virtual contours in comparison with the clinically achieved surgical results. A further objective of the computer-assisted orbital analysis was to use an ideal measurement for the two-dimensional and three-dimensional changes following orbital reconstruction and to check the equality of the postoperative values for the affected orbits in comparison with those of the unaffected sides. Patients with unilateral posttraumatic orbital defects (n = 18) underwent computer-assisted surgery and preoperative planning using a spiral computed tomography database. Surgical procedures were preplanned with virtual correction by mirroring an individually defined three-dimensional segment from the unaffected side onto the deformed side, creating an ideal unilateral reconstruction. These computer-models were intraoperatively used as virtual templates to navigate the preplanned contours and the globe projection using the Stryker-Leibinger navigation system. Individual noninvasive registration with an overall inaccuracy of approximately 1 mm was achieved by using a maxillary occlusal splint with four markers. The mirroring of the unaffected side allowed an ideal virtual reconstruction. A mean decrease in enlarged orbital volume of 4.0 (SD ± 1.9) cm3 was achieved, as was a mean increase in the sagittal globe projection of 5.88 (SD ± 2.98) mm. With a paired Student t test, the decrease between the preoperative and postoperative differences of the affected and unaffected sides was proved significant for orbital volume, globe projection, and computed tomography-based Hertel scale changes (p < 0.01). In 15 of 18 cases, simultaneous malar bone advancement resulted primarily in an additional increase in orbital volume before intraorbital augmentation with calvarial split-bone grafts could be performed. Intraorbital bony augmentation included one (n = 1), two (n = 7), three (n = 8), and all four (n = 2) orbital walls. Computer-assisted preoperative planning enables the surgeon to predict reconstructive surgical steps before the operation. Highly vulnerable structures such as the optic nerve can be detected and avoided intraoperatively, and virtually preplanned bone graft positions and/or orbital frame contours can be checked. Computer-assisted preoperative planning and surgery thus advance the difficult surgical field of orbital reconstruction, particularly through a greater exploitation of radiologic information without additional radiation to the patient.

Normal changes in orbital volume during childhood

The aim of this study was to construct a model of changes in orbital volume that occur throughout childhood from the age of 1 month to 15 years, which could be used for comparative studies of disease states affecting orbital growth. Using the procedure of segmentation on magnetic resonance images obtained in 67 healthy children, orbital volume was measured and plotted against age. During the first few months of life left orbital volume is on average 15 cm3 in male and 13 cm3 in female infants; these volumes increase to 26 cm3 and 24 cm3, respectively, by the time the child reaches 15 years of age. During the first few months of life right orbital volume is on average 16 cm3 in male and 13 cm3 in female infants; these volumes increase to 27 cm3 and 25 cm3, respectively, by the time the child is 15 years old. This represents an overall increase in orbital volume by a factor of 1.7 in boys and 1.8 in girls. By the time the child has reached 5 years of age, the orbital volume for both right and left sides has reached on average 77% of the volume seen at 15 years in both sexes. The differences between the two sides are not statistically significant for either sex. The change in orbital volume that is associated with age in general displays a linear pattern. Throughout childhood, orbital volumes are larger in boys than in girls, but share a similar growth pattern. The difference between the two sexes tends toward statistical significance during the first 5 years of life (left orbit p = 0.1, right orbit p = 0.04). During early childhood, orbital volume increases in a linear fashion, achieving a significant proportion of its final growth by the time the child is 5 years old.

Comparison of pre- and postoperative orbital volume using three dimensional CT imaging in zygoma fracture patients

The aims of this study were (1) to assess the difference between the volume of the traumatized and non-traumatized orbit, (2) to determine the critical change in orbital volume that will result in enophthalmos, and (3) to analyze the correlation between volume discrepancy and clinical outcome in maxillofacial trauma patients. Twenty-seven surgically managed patients with a fracture of the orbitozygomatic complex were included in this study. Preoperative and postoperative volume measurements of both orbits were compared, using software whose accuracy was confirmed in a preliminary experimental study in dry skulls. The correlation between volume discrepancy and clinical enophthalmos was statistically assessed before and after surgery. Preoperatively, there was an increase in orbital volume in 26 of 27 cases, with a range of 0.04–6.02 cc compared with the intact orbits. The mean volume difference between the orbits was 3.01±1.64 cm3 in the preoperative period, and this decreased to 1.02±1.29 cm3 following operation (P<0.01). Five patients (19%) showed clinical enophthalmos with a mean volume difference of 4.77±0.18 cm3 preoperatively. Clinical enophthalmos persisted postoperatively in only one of five enophthalmic patients, in whom the volume discrepancy was greater than 4 cm3. Our data suggested that the technique described here is an easy and accurate method of assessing the volume of the orbit. Orbital volume measurement may help the surgeon to predict volume to be restored and to avoid probable complications.

Quantitative impact of pediatric sinus surgery on facial growth.

To quantitatively evaluate the long-term impact of sinus surgery on paranasal sinus development in the pediatric patient. Longitudinal review of eight pediatric patients treated with unilateral sinus surgery for periorbital or orbital cellulitis with an average follow-up of 6.9 years. Control subjects consisted of two groups, 9 normal adult patients with no computed tomographic evidence of sinusitis and 10 adult patients with scans consistent with sinusitis and a history of sinus-related symptoms extending to childhood. Application of computed tomography (CT) volumetrics, a technique allowing for precise calculation of volumes using thinly cut CT images, to the study and control groups. Paired Student t test analyses of side-to-side volume comparisons in the normal patients, patients with sinusitis, and patients who had surgery revealed no statistically significant differences. Comparisons between the orbital volumes of patients who did and did not have surgery revealed a statistically significant increase in orbital volume in patients who had surgery. Only minimal changes in facial volume measurements have been found, confirming clinical impressions that sinus surgery in children is safe and without significant cosmetic sequelae.

CT assessment of orbital volume in late post-traumatic enophthalmos.

The potential of CT to facilitate preoperative planning of reconstructive maxillofacial surgery by orbital volume quantification was analysed in 11 patients with traumatic enophthalmos as a late sequela of zygomatic fractures. We carried out biplanar CT examination of the orbits, and calculated total orbital and fat volumes for the healthy and enophthalmic sides. Displacement of the orbital floor and lateral wall was present in 11 and 7 cases respectively. Indentation of the medial wall was noted in 9 cases. Quantitative evaluation of the orbital cavity revealed a significant increase (P < 0.0188) in total volume on the enophthalmic side, the difference between the two sides ranging from 9.2% to 36.4%, mean 17.9%. The degree of enophthalmos, measured radiologically as 2.5-5 mm, correlated with the increase in orbital cavity volume (P = 0.000076). Enophthalmos was 2.5-3 mm in 7 cases (63.6%) and 3.5-5 mm in 4 (36.4%). This corresponded with a mean increase in orbital volume of 3.4 ml (12.3%) and 7.1 ml (27.8%) respectively. Fat atrophy was not an aetiological factor in the production of post-traumatic enophthalmos.

Prediction of enophthalmos by computed tomography after 'blow out' orbital fracture.

In 11 patients with blow out fracture of the orbit, measurement of orbital volume using computed tomography (CT) more than 20 days after injury correlated well with enophthalmos measured from the same scans (r = 0.87, p < 0.001, SEE 0.63 mm), with a 1 cm3 increase in orbital volume causing 0.8 mm of enophthalmos. This confirms the cause of enophthalmos after blow out fracture to be increase in orbital volume rather than fat atrophy or fibrosis. In a further 25 patients scanned within 20 days of injury the degree of enophthalmos was less marked than would be predicted from the orbital volume measurement. This was probably because of the presence of oedema, haemorrhage, or both behind the globe which would prevent immediate development of enophthalmos. CT measurement of orbital volume within 20 days of injury may predict the final degree of enophthalmos and identify those patients at risk of late enophthalmos, allowing appropriate early surgical intervention.

Measurement of orbital volumes following trauma using low-dose computed tomography

We describe a simple CT technique for the assessment of enophthalmos and measurement of orbital volumes following trauma. The technique uses original diagnostic CT images, standard CT software and involves no additional radiation dose or scan time. The results of this technique in 66 patients with orbital trauma are presented. The incidence of post-traumatic enophthalmos was significantly raised in association with combined blow-out fractures of the floor and medial wall of the orbit and where orbital blow-out fractures occurred in conjunction with zygomatic injury. Patients without bony imjury had a traumatised orbit volume less than 1 cm3 greater than the non-traumatised side in all cases. Intra-observer reproducibility of the measurement of difference in volume between traumatised and non-traumatised orbit was ± 0.3 cm3 (1 SD). In patients with fracture, increase in orbital volume by more than 2 cm3 compared with the contralateral orbit was strongly associated with enophthalmos (sensitivity 100%, positive predictive value 69%). We conclude that routine volumetric assessment following orbital trauma provides a clinically useful, objective assessment of the risk of post-traumatic enophthalmos and that an increase in orbital volume greater than 2 cm3 is an indication for surgical repair.

Orbital Decompression in Graves' Disease

We studied 42 orbits of 23 patients with Graves' disease who had proptosis secondary to the orbitopathy of their disease and had undergone decompressive operations. The patients were evaluated preoperatively and underwent computed tomography. They were also examined frequently during the first postoperative year and the computed tomography was repeated at 6 months. Three variables correlated well with the reduction in proptosis: the percentage of increase in orbital volume after surgery, the absolute increase in orbital volume, and the degree of orbital "stiffness" as measured preoperatively. The first two variables have an inverse correlation with the third. We refer to the loss of resilience of orbital tissues and the increase in adherence between tissue planes, collectively, as orbital "stiffness." While other factors, such as the size of the anterior opening of the orbit, the resistance of the lid diaphragm, and pressure changes within the orbit, may affect the resultant reduction in proptosis, we did not attempt to measure these factors.

Secondary vascular glaucoma.

Secondary vascular glaucoma is increased intraocular pressure due to venous obstruction in or outside the eye. Its main aetiological features are lesions of the vortex veins and the anterior ciliary veins and orbital and cavernous sinus obstruction; increase in orbital volume, tenonitis/scleritis posterior and idiopathically elevated episcleral venous pressure are described. In 8 out of 148 patients with exophthalmos of various aetiology an abnormal difference in intraocular pressure between the eyes was found, but only 3 of them (2%) had glaucoma; this frequency equals the glaucoma frequency in an average population. In 3 out of 10 patients with tenonitis/scleritis posterior an elevated intraocular pressure was found, in contrast with the normal intraocular pressure found in 20 patients with orbital pseudotumour. Six patients with secondary vascular glaucoma due to elevated episcleral venous pressure of unknown origin were examined; 3 of them had unilateral, the other 3 bilateral, typical lesions. All were female and above the age of 40 years. In contrast with the findings in other investigations, in 3 of these 6 patients orbital neuro-ophthalmological lesions were found.

Increase in Orbital Volume Obtained by Decompression in Dried Skulls

We totally or partially removed the medial wall, floor, lateral wall, or a combination of the three, in four orbits and measured the increased orbital volume that results from the more common orbital decompression techniques. Removal of medial wall alone added 6 cc of volume to the orbit. Removing the floor of the orbit while preserving bone lateral to the infraorbital groove added 7 cc of volume. Removing the lateral floor added 1 cc and removing the lateral wall added 2 cc. Effective lateral decompression, therefore, requires creation of space within the temporal fossa. Removing the wall and the medial floor together added 13 and 14 cc of volume in two separate skulls. The largest volume gained by orbital decompression was 15 cc. This occurred when the entire orbital floor and medial wall were removed. Little volume is lost, however, when the lateral floor is preserved.

Eye and orbital size in the young and adult. Some postnatal experimental and clinical relationships.

The orbital volume in Dutch rabbits ranged from 3.6 ml at 98 days to 5.8 ml at 540 days of age. By 180 days of age the orbital volume had reached about its maximum of 5 ml and was 25% larger than at 100 days of age. The mean orbital volume was less at 540 than at 450 days of age. At 15 days of age the eye volume was about 20% of adult size, at 100 days of age about two thirds, at 180 days of age about 85% of adult size which was reached at about 300 days of age. The mean bulb volume was less at 540 than at 450 days of age. After evisceration, enucleation, or exenteration, in young rabbits there was a decelerated increase of orbital volume and a direct relationship between the lack of intraorbital mass and the subsequent lack of development of the orbit. The addition of a constant-sized implant in the young rabbit, after evisceration or enucleation of the eye, did not enhance orbital growth. In adult rabbits enucleation of the eye did not subsequently alter the orbital volume. In young rabbits an increase of the eye volume after multiple intrabulbar injections of silicone resulted in increase in orbital volume. The same procedure in adult rabbits increased neither the eye nor the orbital volume. Some clinical correlations are made.