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PubMed2004

Epidemiology and management of orbital fractures.

PURPOSE OF REVIEW: Orbital fractures are usually associated with ocular and intracranial injuries. The recent literature on orbital fractures is analyzed with emphasis on epidemiology, assessment, and surgical management. RECENT FINDINGS: In most countries, traffic accidents are the leading cause of orbital fractures. Orbitozygomatic fractures are extremely frequent but rarely addressed in the ophthalmic literature. CT scanning remains the gold standard for assessing orbital fractures, especially with the new CT technology (multislice CT), which has improved the acquisition of coronal images of the orbit without the need for hyperextension of the neck. Several different surgical strategies are used to repair orbital fractures. Porous polyethylene implants continue to be approved by most surgeons. SUMMARY: Orbital fractures are usually part of more complex midfacial trauma. Depending on the main characteristics of the trauma, orbital fractures are managed by different specialists who adopt distinct surgical approaches. Taking into consideration that most complications of these fractures are related to the globe, oculoplastic surgeons in collaboration with other medical specialists are in a prime position to assess and manage these cases.

Humans↗
PubMed2002

Flap tear of rectus muscles: an underlying cause of strabismus after orbital trauma.

PURPOSE: To present an avulsion injury of the rectus muscle after orbital trauma, usually the inferior rectus, and detail its diagnosis and operative repair. METHODS: Forty-three patients underwent repair of flap tears of 62 rectus muscles. During surgery, we found the muscle abnormality was often subtle, with narrowing or thinning of the remaining attached global layer of muscle. The detached flap of external (orbital) muscle was found embedded in surrounding orbital fat and connective tissue. Retrieval and repair were performed in each case. RESULTS: The causes of orbital trauma were as follows: orbital fractures (15 patients), blunt trauma with no fracture (11 patients), suspected trauma but did not undergo computerized tomographic scan (12 patients), and status after retinal detachment repair (5 patients). Of note, 15 of the 43 patients (35%) underwent repair of the flap tear alone, without any additional orbital or strabismus surgery. Diagnostically, the predominant motility defect in 45 muscles was limitation toward the field of action of the muscle, presumably as a result of a tether created by the torn flap; these tethers simulated muscle palsy. Seventeen muscles were restricted away from their field of action, simulating entrapment. The direction taken by the flap during healing determined the resultant strabismus pattern. All patients with gaze limitation toward an orbital fracture had flap tears. The worst results after flap tear repair were seen in patients (1) who had undergone orbital fracture repair before presentation, (2) who had undergone previous attempts at strabismus repair, and (3) who had the longest intervals between the precipitating event and the repair. The best results were obtained in patients who underwent simultaneous fracture and strabismus repair or early strabismus repair alone. CONCLUSIONS: Avulsion-type flap tears of the extraocular muscles are a common cause of posttraumatic strabismus. Early repair produces the best results, but improvement is possible despite long delay.

Adolescent↗
PubMed2003

The effects of airbags on orbital fracture patterns in frontal automobile crashes.

PURPOSE: To investigate orbital fractures that occurred in frontal automobile crashes and to determine the effects of frontal airbags on injury incidence and severity. METHODS: The National Automotive Sampling System database files from 1993 to 2000 were examined. Frontal crashes were selected that included drivers and front-seat passengers only and excluded ejected occupants and rollover crashes. Orbital fractures could be closed, open, displaced, or any combination of these and were identified by using the Abbreviated Injury Scale codes. RESULTS: The analysis included 12,429,580 front-seat occupants from 25,464 cases. Of all occupants who were exposed to an airbag deployment, 0.09% sustained an orbital fracture. In contrast, occupants who were not exposed to an airbag deployment were more than twice as likely to sustain an orbital fracture (0.22%). In addition to reduction in incidence, airbags were also shown to decrease the severity of orbital fractures that occupants sustained. Occupants exposed to airbag deployment mostly sustained closed, less severe fractures (61.9%), whereas occupants not exposed to airbag deployment sustained the majority as more severe, open, displaced, or comminuted fractures (61.3%). CONCLUSIONS: This article presents the most comprehensive study of orbital fractures in automobile crashes to date. It is shown that both the incidence and the overall severity of orbital fractures decreases considerably with exposure to airbag deployment. This is accomplished because the airbag minimizes occupant contact with the windshield and steering wheel, which are the two leading sources of orbital fractures for occupants not exposed to airbag deployment.

Accidents, Traffic↗
PubMed2002

Incorporation of titanium mesh in orbital and midface reconstruction.

Several authors have demonstrated the safety and effectiveness of titanium in orbital reconstruction. One question posed by clinicians is what happens to large pieces of titanium in communication with the paranasal sinuses or nasal-oral-pharyngeal area. This question becomes increasingly relevant as titanium is used to reconstruct extensive defects for which the destruction of bony architecture requires the placement of mesh in proximity to these areas. The objective of this study was to examine the gross and histologic soft-tissue response to large segments of titanium mesh in the setting of orbital and midface reconstruction, particularly when exposed to the nasal-oral-pharyngeal area and paranasal sinuses. In this study, large segments of titanium mesh were used in eight patients to reconstruct orbital and midface defects, with direct communication between the mesh and nasal-oral-pharyngeal area and paranasal sinuses. Four patients had suffered self-inflicted gunshot wounds; as a result, much of their midface was missing, including the inferior and medial orbital floor, maxilla, nose, naso-orbital-ethmoid complex, and hard palate. Extensive sheets of titanium mesh were used to reconstruct their medial and inferior orbital walls, nasal bridge, and maxilla. In the fifth patient, titanium mesh was used to reconstruct the maxilla after resection of a squamous cell carcinoma of the nasolacrimal duct. In the sixth and seventh patients, mesh was used to reconstruct the nasal bridge after severely comminuted nasal fractures resulted in the loss of bone and mucosa. Finally, the eighth patient had titanium mesh used to replace cocaine-induced bone loss involving the left medial orbital floor and wall and part of the maxilla. On gross examination by either endoscopy or direct inspection, all eight patients had rapid soft-tissue incorporation of the titanium mesh. Initial examination typically revealed budding of soft tissue through mesh interstices, followed by progressive incorporation. One patient's mesh was covered in only 15 days. Two patients underwent biopsies of this newly formed soft tissue. One had biopsies performed at 3, 15, and 31 months after the original operation. Biopsy examination at 3 months revealed incorporation of the titanium with fibrous soft tissue covered by ciliated respiratory epithelium, goblet cells, and squamous epithelium with metaplasia. In addition, the dense, acute inflammation present at 3 months evolved into mild, chronic inflammation at 31 months. The second patient had a single biopsy 4 months after secondary orbital reconstruction for delayed enophthalmos. Biopsy examination revealed a fibrous soft-tissue sheath lined by squamous epithelium with metaplasia. Again, mild chronic inflammation was present within the soft tissue. This study provides evidence of titanium's compatibility with soft tissue. The mesh underwent progressive incorporation with soft tissue that was then resurfaced by indigenous cells, including respiratory epithelia and goblet cells. This phenomenon occurred despite communication with the nasal-oral-pharyngeal area and paranasal sinuses.

Bone Diseases↗
PubMed2005

Internal fixation in trapdoor-type orbital blowout fracture.

BACKGROUND: The most common orbital blowout fracture is a trapdoor type. In many cases of trapdoor fracture, the bony segment has a stable hinge consisting of a greenstick fracture and the sinus mucoperiosteum that is attached to the intact orbital wall. If the displaced bony segment opposite the hinge is reduced into the original position and fixed on the unaffected bone, the orbital fracture may be reconstructed by internal fixation of the bony segment itself rather than requiring substitution with alloplastic implants or a bone graft. METHODS: In 20 cases of orbital blowout fracture of a trapdoor type, internal fixation was performed using a cantilever fixation technique (with a piece of titanium micromesh or a titanium microplate plus a microscrew) or a ledge fixation technique (with a piece of micromesh). RESULTS: In all cases, the orbital wall was accurately reconstructed in its normal anatomical position. The associated ocular problems disappeared except for mild diplopia in one patient and there were no surgical complications associated with the internal fixation. CONCLUSIONS: The advantages of internal fixation include anatomical reconstruction of the orbital wall; preservation of the original orbital bone and the mucoperiosteum of the sinus as an osteomucoperiosteal flap resulting in rapid wound healing and normal mucus drainage function of the sinus; the simplicity of the procedure; and consequently, the absence of surgery-related complications. This technique is presented as one of the preferred treatments for trapdoor-type orbital blowout fractures.

Adolescent↗
PubMed2004

Implication of differences in the incidence of orbital emphysema in ethmoidal and maxillary sinus fractures.

This study investigated the incidence of orbital emphysema in patients with fractures of the ethmoidal cells or maxillary sinus. We noted that mucosal destruction is essential for orbital emphysema to occur. Computed tomographic examination and intraoperative studies of 58 patients with orbital bone fracture were performed with the patients divided into 2 groups according to the location of the fracture lines. The incidences of orbital emphysema and of intrasinus hematoma were significantly higher in the group with medial orbital bone fracture of ethmoidal cells than in the group with maxillary sinus fracture, which indicates mucosal tear was significantly higher in the former group. Fractured lamina papyracea and intrasinus hematoma were observed in all cases with ethmoidal sinus fracture. On the other hand, intrasinus hematoma was not found in some cases with maxillary sinus fracture, blowout fracture of the orbital floor, or zygomatic bone fracture, while all cases with orbital emphysema were included in the cases with intrasinus hematoma. This suggests that the incidence of orbital emphysema depends on the occurrence of tearing of the mucosa of the paranasal sinus.

Emphysema↗
PubMed2006

Modelling of orbital deformation using finite-element analysis.

The purpose of this study was to develop a three-dimensional finite-element model (FEM) of the human orbit, containing the globe, to predict orbital deformation in subjects following a blunt injury. This study investigated the hypothesis that such deformation could be modelled using finite-element techniques. One patient who had CT-scan examination to the maxillofacial skeleton including the orbits, as part of her treatment, was selected for this study. A FEM of one of the orbits containing the globe was constructed, based on CT-scan images. Simulations were performed with a computer using the finite-element software NISA (EMRC, Troy, USA). The orbit was subjected to a blunt injury of a 0.5 kg missile with 30 ms(-1) velocity. The FEM was then used to predict principal and shear stresses or strains at each node position. Two types of orbital deformation were predicted during different impact simulations: (i) horizontal distortion and (ii) rotational distortion. Stress values ranged from 213.4 to 363.3 MPa for the maximum principal stress, from -327.8 to -653.1 MPa for the minimum principal stress, and from 212.3 to 444.3 MPa for the maximum shear stress. This is the first finite-element study, which demonstrates different and concurrent patterns of orbital deformation in a subject following a blunt injury. Finite element modelling is a powerful and invaluable tool to study the multifaceted phenomenon of orbital deformation.

Computer Simulation↗
PubMed1998

Bony orbital morphology in neurofibromatosis type 1 (NF1).

We retrospectively compared patients with NF1 with and without optic pathway gliomas (OPG) to determine the incidence and range of orbital developmental abnormalities and compared the incidence of OPG in African-Americans and whites. From cranial MR scans, we manually measured 14 orbital dimensions, compared them to published standards of Waitzman et al, calculated orbital volumes, and determined the presence or absence of volumetric symmetry (delta v) (delta v < or = 3 cm3 was considered to be symmetrical). We compared the results of orbital configurational assessment between patients with (group I) and those without OPG (group II). The study population comprised 58 patients, 24 boys, 18 African-American, and one Hispanic. Median age at imaging was 7 years (range 0.5-25.5 years). Fifty-eight percent had conformational abnormalities, 16 of whom had more than one abnormality (28%), the most frequent being increased intertemporal distance (n=10), increased lateral orbital distance (n=8), increased medial wall length (n=6), and decreased medial wall length (n=6). The increased intertemporal and lateral orbital distances may contribute to the appearance of hypertelorism. Only two patients had sphenoid wing hypoplasia. We found a high incidence of orbital dimensional abnormalities in the total population but more often saw multiple abnormalities in patients with OPG. However, no pattern of configurational abnormality emerged. OPG is less frequent in African-Americans. Orbital volumetric disparity seems to be independent of the presence of OPG.

Adolescent↗
PubMed1978

[Results with non-fixed silicone implants in the treatment of blow-out-fracture and fracture of the orbit].

The number of difficult maxillofacial fractures increases with the number of traffic accidents. 80% of all accidents of this kind are accompanied by juries of the head. In the treatment of combined blow-out-fracture and fracture of the orbit, the most important task is a repair of all orbital structures in collaboration of the ophthalmologist with the otolaryngolist and the oral surgeon. A knowledge of all orbital fractures (stages according to Bleeker) is an essential basic requirement. Bigger defects of the orbital walls are closed by me with one, two or three perforated silicon implants in accordance with Whyte. The open repair of the orbital ring with intraosseous fixation is the modern method of treatment of dislocated orbital bones. After a detailed description of my own operative procedure the treatment results of 75 combined blow-out-fractures--among them 4 orbital fractures of the floor, walls, roof and margins--are given. The following complications are listed: 1 case of orbital hemorrhage, 36 cases of persistent lower lid edema, 4 cases of tissue reaction to the alloplast, 3 cases of infection )amoung them one otolaryngolical case) and 5 cases of extrusion of the implant.

Adolescent↗
PubMed1984

Schwannoma of the orbit.

Schwannoma of the orbit is an encapsulated, benign, noninvasive, slow-growing nerve sheath tumor which, when large enough, causes exophthalmos, optic neuropathy, diplopia, anterior orbital mass or sinusitis. An orbital schwannoma in a 84-year-old man with infiltration of the os spenoidale is reported. Schwannoma may arise anywhere within or adjacent to the orbit and is usually curable by local excision. The malignant counterpart, the malignant schwannoma, is exceedingly rare in the orbit. In orbital tumors many diagnostic steps are necessary, but the exact diagnosis is often determined only by histological examination. Schwannomas (synonyms neurilemoma, neurinoma) of the orbit are rare; they account for 1-6% of all orbital tumors. Here presented is a description of their appearance on clinical examination and on light and electron microscopy, together with a report on preoperative investigations and operative findings.

Aged↗
PubMed1991

Blindness resulting from orbital complications of sinusitis.

Loss of vision remains a potential complication of orbital infection. Appropriate evaluation and management of the patient with signs and symptoms of orbital inflammation may prevent progression to blindness. Evaluation of patients with orbital inflammation from sinusitis includes a comprehensive clinical examination and radiographic studies. Clinical examination should test for changes in visual acuity, pupillary reactivity, and extraocular motion. Computerized tomography (CT) has facilitated the diagnosis of orbital infections and aids in diagnosis. However, CT can be misleading in patients with acute orbital infections and should not be relied on to determine the need for surgical intervention. We reviewed the records of all patients admitted to Parkland Memorial Hospital from 1978 to 1988 with orbital complications resulting from sinusitis. Four of 159 patients in this group had permanent blindness. The presence of an abscess, which was ultimately found at surgical exploration, was not diagnosed by CT in any of these four patients. Clinical examination remains the most important indicator for surgical intervention in patients with orbital complications of sinusitis. We present our findings and give guidelines for surgical intervention in patients with orbital infections resulting from sinusitis.

Abscess↗
PubMed1995

Medial orbital wall fractures: classification and clinical profile.

This article reports our experience and proposes a clinical classification regarding medial orbital wall fractures. After a retrospective analysis of 2741 patients with facial fractures, we were able to evaluate 273 patients with 304 medial orbital wall fractures. The male-to-female ratio was 5:1, and most injuries involved the left orbit. Most fractures were caused by personal altercations, but more complex injuries were noted with automobile accidents and falls. Fractures were divided into types based on location and severity of injury: type I (confined to the medial orbital wall), type II (medial orbital wall continuous with floor), type III (medial orbital wall with floor-malar fractures), and type IV (medial orbital wall and complex midfacial injuries). Although visual loss (2%), diplopia (41%), and enophthalmos (12%) were seen, diplopia and enophthalmos were commonly observed with type II injuries. Imaging studies showed that about 52% of the fractures were associated with prolapse of orbital fat, but only 43% could be diagnosed with plain x rays. Type I fractures were generally explored through a frontoethmoid incision; other types were treated with subciliary or transconjunctival approaches. The usual treatment consisted of repositioning the fragments and repair of the wall with polyethylene mesh or cranial bone graft. Type I and type II fractures seemed best explained by the hydraulic mechanism of injury, whereas the type III and type IV fractures best fitted the buckling theory.

Accidents, Traffic↗
PubMed1995

Evidence for cellular heterogeneity in primary cultures of human orbital fibroblasts.

Orbital fibroblasts in culture display phenotypic attributes that distinguish them from fibroblasts derived from other anatomical regions. The current studies were conducted to define potential cellular heterogeneity among orbital fibroblasts with regard to 1) differential expression of Thy-1, a 25-kilodalton glycoprotein associated with cell signaling; 2) cells undergoing a change in shape in response to prostaglandin E2 (PGE2); and 3) differences in morphology and Thy-1 expression between single cell-derived clonal fibroblast strains. On the basis of flow cytometric analysis using an anti-Thy-1 monoclonal antibody, 65% of intact orbital fibroblasts expressed surface Thy-1 (n = 5; range, 54-71%). In contrast, greater than 95% of the fibroblasts present in the five dermal strains tested were Thy-1 positive. A total of six strains of orbital fibroblasts were assessed for their shape change response to a 4-h treatment with PGE2 (100 nmol/L). A mean of 37% of the fibroblasts present in each culture responded to PGE2 (range, 22-50%). In contrast, only 1% of dermal fibroblasts exhibited any change in morphology. Three separate clones were generated from a single parent strain of Graves' orbital fibroblasts. These clones consisted of homogeneous appearing cells; however, substantial clone to clone differences in morphology were stably expressed for several population doublings. Thy-1 was expressed uniformly in cells of two clones, whereas the third was Thy-1 negative. Factor VIII and smooth muscle-specific alpha-actin were undetectable in any of the orbital or dermal cultures examined. Thus, Thy-1 expression is uniform in fibroblasts from certain anatomical regions such as the skin and heterogeneous in cells derived from human lung and orbit. These findings suggest that human orbital connective tissue may have a complexity not previously appreciated.

Antigens↗
PubMed1998

Thyrotropin receptor expression in Graves' orbital adipose/connective tissues: potential autoantigen in Graves' ophthalmopathy.

It is acknowledged that the TSH receptor (TSHr) on thyroid follicular cells is the autoantigen involved in the hyperthyroidism of Graves' disease. However, whether this receptor is expressed in extrathyroidal tissues, and whether it participates directly in the pathogenesis of Graves' ophthalmopathy (GO) are unclear. We sought to detect the expression of TSHr messenger ribonucleic acid (mRNA) and protein in orbital adipose/connective tissue specimens and in human orbital preadipocyte fibroblast cultures using liquid hybridization analysis and immunohistochemical methods. We demonstrated intact and variant TSHr mRNA transcripts and TSHr-like immunoreactivity in orbital adipose/connective tissue specimens from patients with GO. In addition, TSHr-like immunoreactivity was detected in early passage GO preadipocyte fibroblast cultures that were shown to include some adipose cells. In contrast, neither TSHr mRNA nor protein was detected in normal orbital adipose/connective tissue specimens or in late passage GO orbital fibroblast cultures containing no lipid-laden adipose cells. In conclusion, we showed that TSHr is expressed in the adipose/connective tissue of the diseased orbit in GO. In addition, TSHr is demonstrable in early passage GO preadipocyte orbital fibroblast cultures that contain a subpopulation of adipocytes. Subsequent passaging of these cells results in the loss of both TSHr expression and adipocyte-specific staining. These results suggest that both the expression of this receptor and the accumulation of adipose tissue in the orbit in GO may be induced in vivo by a humoral factor(s) not present in the cell culture environment.

Adipocytes↗
PubMed1988

Structural mechanics of the blowout fracture: numerical computer simulation of orbital deformation by the finite element method.

Blowout fractures most frequently involve the orbital floor. The contour of the orbit has been postulated as one of the factors responsible for this phenomenon, but only a few studies have been carried out. The present study was planned to determine the effect of the contour of the orbit when intraorbital pressure is raised to simulate the hydraulic mechanism of blowout fracture. The profile of the orbit was estimated from five dry human skulls, and the measurements were approximated to frame models. The deformation of these models by raised intraorbital pressure was calculated by computer simulation using the finite element method. In all of the orbital models, the deformation of the orbital floor was significantly greater than that of the roof. These findings verified that the orbital roof has a higher resistance than the floor against raised intraorbital pressure. We suspect that this resistance is due to the arched shape of the orbital roof, whereas the floor is rather flat.

Computer Simulation↗
PubMed1992

Surgical strategies in the treatment of symptomatic osteomas of the orbital walls.

We present a series of 19 surgically treated osteomas involving the orbital walls. Eight were localized at the junction of the frontal sinus and orbital roof, three were frontoethmoidal, two were of the orbital roof, one of the lateral wall, one of the orbital floor, and four involved all the walls of the orbit and were termed panorbital. All tumors at the junction of the frontal sinus and the orbital roof as well as those originating from the orbital roof proper were removed by frontal craniotomy. In the three that were frontoethmoidal, osteotomies were performed. Lateral and inferior orbitotomies were done when the corresponding orbital walls were affected. The four panorbital osteomas required large frontotemporal craniotomies in association with superolateral orbitotomy and zygomatic and/or malar osteotomy, when necessary. Satisfactory cosmetic and functional results were obtained in all but two cases of panorbital osteomas, in which the neurological deficit worsened after surgery. We discuss the choice of the various approaches described, with reference to the relevant literature.

Adult↗
PubMed2002

Endoscopic orbital decompression for Graves' ophthalmopathy.

Graves' disease may occasionally result in significant proptosis that is either cosmetically unacceptable or causes visual loss. This has traditionally been managed surgically by external decompression of the orbital bony skeleton. Trans-nasal endoscopic orbital decompression is emerging as a new minimally-invasive technique, that avoids the need for cutaneous or gingival incisions. Decompression of the medial orbital wall can be performed up to the anterior wall of the sphenoid sinus. This can be combined with resection of the medial and posterior portion of the orbital floor (preserving the infra-orbital nerve). This technique produces decompression which is comparable to external techniques. We present a series of 10 endoscopic orbital decompressions with an average improvement of 4.4 mm in orbital proptosis. There was an improvement in visual acuity in all patients with visual impairment. Endoscopic orbital decompression is recommended as an alternative to traditional decompression techniques.

Decompression, Surgical↗
PubMed2003

Evaluation of coronal CT findings of rare cases of isolated medial orbital wall blow-out fractures.

OBJECTIVES: To report rare cases of isolated medial orbital wall blow-out fractures and to evaluate their coronal CT findings. METHODS: Nine cases of medial orbital wall blow-out fractures, diagnosed by coronal CT in a general medical hospital between 1995 and 1999, were studied. CT was performed using direct coronal acquisition with a slice thickness of 5 mm. Images were obtained at bone window settings. Clinical examination findings from the medical records were used to give information on the cause of injury, ocular symptoms and the days after injury that the CT examination was performed. RESULTS: Most of the patients (67%) were young male adults. The cause of injury was most frequently the result of fist fighting or athletics (78%). Diplopia and/or limitation of the gaze were the main ocular symptoms (78%). The average time from injury to CT examination was 4 days (range 0-16 days). Seven of the nine patients with medial orbital wall fractures had isolated medial orbital wall blow-out fractures. Herniation of orbital contents toward the ethmoid sinus was observed among all nine fractures. Only three patients (33%) had a swelling and/or medial deviation of the medial rectus muscle, all three having isolated medial orbital wall blow-out fractures. CONCLUSIONS: Nine cases of medial orbital wall blow-out fractures were examined, seven of which were isolated medial wall blow-out fractures. CT findings of this type of fracture included herniation of the orbital contents toward the ethmoid sinus. However, swelling and/or medial deviation of the medial rectus muscle was also seen.

Adolescent↗