Ocular motility alterations in orbital fractures: pre-post evaluation in maxillofacial surgical treatment

PURPOSE

The study aims to investigate the ability of maxillofacial surgery to reduce strabismus and improve ocular clinical symptomatology in patients with fracture of the medial or lateral floor of the orbit, or both, and to evaluate such abilities relative to the temporal distance between trauma and surgery.

PATIENTS AND METHODS

25 patients with traumatic diplopia were evaluated by CT, Goldman manual field of view, Hess-Lancaster test, eye examination and orthoptic examination, before and after surgery.

RESULTS

We observed: a statistically significant reduction of the deviation angle, both from close and long distance (P = 0.0054 and P = 0.0051 respectively) with a 38% reduction of the deviation from short distance and 54% from afar; a regression of diplopia in 20% of the surgically treated cases (CL from 0 to 39%), significant at the Mc Nemar test; a negative correlation with the time elapsed between the onset of the fracture and maxillofacial surgery (R = -0.26), even if the analysis did not show a statistical significance of the data (P = 0.2). However, it is evident that the maximum improvement is observed only in cases operated within 5 months of the trauma, while the failures (worsening or persistence of diplopia) were observed only in the cases operated later.

CONCLUSION

We can state that the intervention reduces strabismus and improves ocular symptomatology, as it statistically significantly reduces cases of diplopia; furthermore, it would seem preferable to intervene early, especially when damage to a muscular structure is suspected, even if the data do not allow definitive conclusions in this regard.

Blowout fractures - clinic, imaging and applied anatomy of the orbit

Isolated fractures of the orbital floor or medial wall are often referred to as blowout fractures (BOFs). Debilitating double vision and aesthetic deformity may affect the patients' quality of life and daily living skills, for instance, working or driving a car. The management of blowout fractures is, however, challenging, since not all fractures demand surgery. Some patients may have symptoms which subside, or may never develop symptoms. Due to a lack of evidence, there are still considerable differences in opinion on the criteria for surgery. The selection of patients for surgery is therefore crucial for optimal patient outcomes. 
The aims of this PhD project were to elucidate and investigate various clinical aspects of blowout fractures and to examine the anatomy of the orbital cavity, which included studying the symmetry of the two orbits, the location of orbital arteries, and the pathophysiology of blowout fractures. Several clinical specialties and basic research fields study the orbital cavity. The studies in this PhD project are based on collaboration between the Departments of Otorhinolaryngology, Ophthalmology and Radiology at the Copenhagen University Hospital Rigshospitalet and the Departments of Odontology and Anatomy (Cellular and Molecular Medicine) at the University of Copenhagen. 
We assessed the current treatment of blowout fractures at the Ear Nose and Throat (ENT) Department at our tertiary hospital in a retrospective study, and found that a third of the patients had persistent double vision 3 months post-trauma, irrespective of whether they had been managed surgically or conservatively (Paper I). We found that the left and right orbit are symmetrical with regards to various morphometrics of both the bony orbit and the intraorbital contents, e.g. volume, surface area and volume of fat and extraocular muscles, and distance to the ethmoidal arteries (Papers II, III and IV). This knowledge may be used in blowout fracture studies on surgical decision-making and orbital reconstruction and also in presurgical planning to avoid iatrogenic damage to the ethmoidal arteries in orbital surgery. In the first longitudinal MRI study of blowout fractures, dynamic post-traumatic changes in the intraorbital soft tissue were detected, i.e. to the best of our knowledge, for the first time indicative of an edema. We conclude that an edema subsides in the days following a blowout fracture and recommend a watchful waiting period before deciding on whether or not to operate (Paper III).
 The 24-12-6 mm rule of thumb determines orbital distances from the anterior lacrimal crest to the ethmoidal arteries and the optic canal. We questioned the applicability of this rule to all patients and investigated whether or not it is feasible to measure the distances on CT images. We found large inter-individual differences in the distances to the ethmoidal arteries and found that preoperative measurements on CT images are feasible and produce results with a low intra- and inter-observer variability.

Pediatric orbital wall fractures: Prognostic factors of diplopia and ocular motility limitation

Objectives

To investigate the factors affecting recovery of diplopia and limited ocular motility in pediatric patients who underwent surgery for orbital wall fracture.

Design

Retrospective observational case series.

Methods

In this retrospective observational case series, 150 pediatric patients (1–18 years old) who were diagnosed with orbital medial wall or floor fracture and underwent corrective surgery between 2004 and 2016 at Seoul National University Bundang Hospital were included. The medical records of patients with orbital medial wall or floor fracture were reviewed, including sex, age, diplopia, ocular motility, preoperative computed tomographic finding, and surgical outcomes. Factors affecting recovery of diplopia and ocular motility limitation were analyzed.

Results

Of the 150 patients (134 boys; mean age, 14.4 years) who underwent corrective surgery for orbital wall fracture, preoperative binocular diplopia was found in 76 (50.7%) patients and limited ocular motility in 81 (54.0%). Presence of muscle incarceration or severe supraduction limitation delayed the recovery of diplopia. In case of ocular motility limitation, presence of muscle incarceration and retrobulbar hemorrhage were related with the delayed resolution. Multivariate analysis revealed supraduction limitation (Hazard ratio [HR] = 1.74, 95% confidence interval [CI] = 1.19–2.55), larger horizontal orbital floor defects (HR = 1.22, 95% CI = 1.07–1.38), and shorter time interval to first visit (HR = 0.73) as negative prognostic factors for the recovery of diplopia. In addition, muscle incarceration (HR = 3.53, 95% CI = 1.54–8.07) and retrobulbar hemorrhage (HR = 3.77, 95% CI = 1.45–9.82) were found as negative prognostic factors for the recovery of motility limitation.

Conclusions

Presence of muscle incarceration and retrobulbar hemorrhage, horizontal length of floor fracture, supraduction limitation, and time interval from trauma to first visit were correlated with the surgical outcomes in pediatric orbital wall fracture patients. These results strengthen that the soft tissue damage associated with bony fracture affects the orbital functional unit. When managing children with orbital wall fracture, meticulous physical examination and thorough preoperative computed tomography based evaluation will help physicians to identify damage of orbital functional unit.

Treatment of Orbital Roof Blow-Up Fracture Using a Superior Blepharoplasty Incision

In orbital roof blow-up fractures, reduction can be achieved easily using an approach from the anterior cranial fossa but the procedure is highly invasive. In contrast, an orbital approach using a superior blepharoplasty incision is minimally invasive. However, if bone fragments are adhered to the dura mater, there is a risk of dura mater injury when fragments are moved for reduction. In blow-in fractures, reduction is performed by pushing the bone fragments against the anterior cranial fossa. In contrast, the procedure is difficult for blow-up fractures because bone fragments must be pulled out into the orbit through the anterior cranial fossa. Orbital blow-up fractures are often associated with intracranial injuries and frequently treated by an approach from the anterior cranial fossa. There has not yet been a report that discusses whether reduction of bone fragments should be performed in blow-up fracture without intracranial injury. In this report, we describe two cases of orbital roof blow-up fracture that did not require treatment for intracranial injury and that were treated using an orbital approach. The treatment involved only the release of orbital fat entrapped between bone fragments and did not involve reduction. The treatment outcomes were good in both cases.

[Modern aspects of reconstructive surgery for orbital trauma]

The article describes the symptoms of an indirect orbital injury. Special attention is paid to clinical manifestations of muscle entrapment after trapdoor fractures in pediatric patients. Advantages of an original method of functional MSCT for orbital trauma are specified. Indications for orbital wall reconstruction, surgical approaches, the range of modern materials for orbital implantation, and problems of isolated orbital fractures repaired by craniofacial surgeons are considered from the ophthalmologist point of view.

[Pre- and postoperative ocular blood flow in transconjunctival orbital surgery]

OBJECTIVE

to evaluate the pre- and postoperative ocular blood flow in patients with post-traumatic orbital deformities who underwent transconjunctival orbital reconstruction.

MATERIAL AND METHODS

A total of 40 patients with post-traumatic deformities of the inferior and medial orbital walls were examined before and after transconjunctival "Alloplant" implantation to the orbit.

RESULTS

Before the surgery, blood flow deficiency in a. ophthalmica and elevation in peripheral vascular resistance were found in all patients. Postoperatively, orbital hemodynamic parameters were restored and remained stable over the whole follow-up period.

CONCLUSION

Post-traumatic disturbances of regional blood flow are revealed and postoperative changes of the relevant parameters are assessed.

[Functional multislice spiral computed tomography of the rectus muscle of the eye in scar changes]

The study deals with the capacities of functional multislice spiral computed tomography (FMSCT) in choosing a treatment policy and planning the tactic and scope of surgery for posttraumatic scar changes in the rectus muscle of the eye. Orbital MSCT and FMSCT were conducted in 15 patients (30 orbits). The findings showed that it was necessary to perform orbital FMSCT in posttaumatic scar changes to evaluate the contractility of the rectus muscles and their involvement in the area where a fracture occurs. Improved diagnosis achieved by FNSCT could optimally choose the tactics and scope of surgical intervention.

Mechanisms of orbital blowout fracture: a critical review of the literature

OBJECTIVE

The aim of the present study is to critically review relevant literature regarding the mechanism of blowout fractures of the orbit and provide an answer to the question: Can one theory adequately explain the mechanism of orbital blowout fractures in the light of present day knowledge?

MATERIALS AND METHODS

A computerised literature search using MEDLINE was conducted for published articles on orbital blowout fractures. Mesh phrases used in the search were: orbital blowout fractures AND mechanisms; orbital blowout fractures AND theory; orbital wall injury AND mechanisms. Only relevant articles were selected for the review.

RESULTS

The physical mechanism of orbital blowout fracture has been a subject of debate for years by maxillofacial surgeons, ophthalmologists, plastic surgeons, otolaryngologists and orbitologists. However, only 3 mechanisms of injury have been proposed namely: "hydraulic" theory, "globe-to-wall" theory and "bone conduction" theory. Most of the theories of orbital blowout fractures have been confirmed through brilliant experiments and hypothetical explanation/analysis of clinical and radiologic findings, and each one appears to fit according to the different type of trauma received.

CONCLUSIONS

Based on contemporary evidence, one theory may not adequately explain all types of fractures completely or be responsible exclusively in a given case for the pattern of fracture observed. Blowout fractures of the orbit could therefore be due to a combination of 2 or more mechanisms.

Direct orbital manometry in normal and fractured orbits of Chinese patients

PURPOSE

This study measured direct orbital tension (DOT) in normal and fractured orbits of Chinese patients before and after orbital fracture repair, to investigate the changes in DOT and intraocular pressure (IOP) after surgery and to evaluate any correlation between them.

MATERIALS AND METHODS

DOT was directly measured by a specially designed orbitonometer before and after orbital fracture surgery in 40 cases of unilateral orbital fractures, using the contralateral eyes as a control group. All of the patients were submitted to orbital fracture repair and globe repositioning. IOP and ocular function were recorded preoperatively and postoperatively.

RESULTS

DOT was 5.0 +/- 1.3 mm Hg (mean +/- SD) in the normal orbits. DOT was positively correlated with IOP (r = 0.56; P < .01). DOT and IOP were significantly decreased (s = 81, P = .01 and s = 49.5, P = .02, respectively) on the fractured orbit side. Postoperative DOT and IOP were significantly increased (s = 410, P < .01 and s = 390, P < .01, respectively). The preoperative to postoperative changes in both DOT and IOP were positively correlated (r = 0.54; P < .01).

CONCLUSIONS

DOT can be measured safely using an orbital manometer in normal and fractured orbits. DOT and IOP increased significantly after orbital fracture surgery. DOT was well-correlated with IOP both preoperatively and postoperatively.

Association Between Ocular Injuries and Internal Orbital Fractures

PURPOSE

The physical mechanism of orbital blowout fractures has been debated for years by surgeons. Three main theories have been promulgated, including the hydraulic theory, the contact of globe-to-orbital wall theory, and the bone buckling theory. One might anticipate a strong association of blowout fractures and traumatically induced ocular injuries with the hydraulic and globe-to-wall theories because in both, the force is delivered directly to the ocular globe. This study was performed to assess the association between orbital blowout fractures and ocular injuries.

PATIENTS AND METHODS

Records of patients with orbital blowout fractures were collected from a single hospital. Those with complete records that included a thorough ophthalmologic examination were collected, and information about the nature of the injury to the bone and the ocular globe was tabulated.

RESULTS

A total of 225 patients ranging in age from 13 to 98 years (mean, 34.9 yr) who had sustained 240 blowout fractures (15 were bilateral) met the inclusion criteria. In all, 53 fractures (22%) involved ocular injuries that were thought to be directly associated with ocular trauma. The most common positive ocular finding was commotio retinae, which was present in 21 of 60 globes with significant traumatic ocular findings. This was followed in frequency by traumatic mydriasis (19 globes) and traumatic iritis (15 globes). Most ocular injuries were minor.

CONCLUSIONS

The low incidence of significant ocular injury may indicate that direct contact of the globe with the traumatic force is not common. This finding gives credence to the buckling theory of blowout fracture, which seems more likely in most cases.

Traumatic bitemporal hemianopia

A 45-year-old male pedestrian was struck by a motor vehicle moving at high speed. Upon initial assessment, the patient scored a 3T on the Glasgow Coma Scale. The patient suffered multiple facial and sinus fractures, a right orbital wall fracture, and a depressed open frontal skull fracture with visible brain parenchyma. Due to the nature of the brain injury, the patient was taken to the operating room emergently for a right frontal craniectomy. The patient required prolonged hospitalization followed by transfer to a rehabilitation facility. Six weeks after the accident, the patient underwent an extensive neuro-ophthalmologic evaluation. At that time, visual acuity was 20/200 in both eyes. On visual field testing, a bitemporal hemianopia was noted. Ophthalmoscopic examination revealed bilateral temporal disc pallor, right greater than left. Neuroimaging demonstrated damage to the optic chiasm. Although rare, head trauma may cause a bitemporal hemianopia secondary to optic chiasmal injury.

Untersuchungen zum Entstehungsmechanismus der isolierten Orbitabodenfraktur

BACKGROUND

Isolated orbital floor fractures make up a significant proportion of all facial injuries, but the mechanism involved in these injuries to the orbital walls (blow-out fractures) has not yet been completely defined. Two theories have been described, which seem to be mutually exclusive. According to the hydraulic pressure theory, the kinetic energy of the blow is transferred via the incompressible eye tissue to the floor of the orbita, which in turn fractures. The buckling force theory, in contrast, explains these fractures as the result of bending and shear stresses arising from kinetic energy act directly on the orbital rim.

MATERIALS AND METHODS

With the aim of elucidating the mechanism of injury, we constructed a simplified finite-element model of the human orbita by 3D optical scanning of a human skull obtained after an autopsy examination. We created a generic approximation model based on empiric data derived from femoral fractures and reported in the literature. Several experiments were conducted to test both the above hypotheses by direct and indirect application of kinetic energy.

RESULTS

We simulated different types of shear stress with the finite-element model of the skull. The calculated points of maximum pressure were all within the orbital floor.

CONCLUSION

The simulation showed that both mechanisms can lead to fractures, as also documented by recent studies. The generation of a finite-element model and simulation of stresses were initially useful in establishing a method. More detailed studies on the empiric data relating to the various structures and more extensive determination and measurement of different skull and/or orbita geometries are needed before we can achieve a model in which the mechanical attributes of the structures involved are reproduced with closer approximation to the real-life situation.

Correlation between ocular motility and evaluation of computed tomography in orbital blowout fracture

PURPOSE

To investigate outcomes of management of blowout fracture patients evaluating computed tomography (CT) findings and diplopia.

DESIGN

Single-center retrospective interventional consecutive case series.

METHODS

This study included 113 cases of pure blowout orbital fracture with diplopia. We investigated patients' satisfaction based on percentage of Hess area ratio (HAR%) on the Hess chart, evaluating fracture type and number of points of contact of extraocular muscles to the fracture edge (points of muscle contact) based on CT.

RESULTS

Of the patients with HAR% > 85%, most experienced no diplopia. Sixty-two (55%) of 113 patients underwent surgical repair to improve diplopia, and 31 (50%) of 62 patients had surgery within three days after injury. A favorable outcome with HAR% > 85% was seen in 81 (72%) of 113 patients. Of 32 patients with two points of muscle contact at one extraocular muscle, 15 patients (47%) improved with a final HAR% > 85%. None of the four patients with medial wall fracture and two points of muscle contact had improved in their final HAR% > 85%. Thirty (97%) of 31 patients with either floor or medial wall fracture and no muscle involvement had a favorable outcome regardless of fracture type. Initial CT findings of the rectus muscle was strongly correlated with a mean initial HAR% (r = -0.94) and a mean final HAR% (r = -0.87).

CONCLUSIONS

The clinical manifestations and prognosis of patients were approximately predicted through the analysis of CT on fracture type and number of points of contact of an extraocular muscle to the fracture edge.

Orbito-cranial injuries caused by penetrating non-missile foreign bodies. Experience with eighteen patients

BACKGROUND

Penetrating non-missile orbito-cranial injuries are uncommon civilian injuries which have some special features. Only limited case-reports are available in the international literature.

METHOD

We present a retrospective review of 18 such in presumed trivial orbital injury. Early identification and removal of retained foreign body fragments was achieved within 36 hours.

FINDINGS

Patients were operated on and followed up for at least of 3 years. The final clinical outcome was excellent: 16 had a Glasgow Outcome Scale (GOS) of 5 while in the remaining 2 it was 4.

CONCLUSION

The present report indicates that good results, in managing such injuries, can be achieved by a high index of suspicion and early diagnosis of intracranial injury in presumed trivial wounds and by the removal of every possible retained foreign body.

Recognition and management of an orbital blowout fracture in an amateur boxer

STUDY DESIGN

Case report.

OBJECTIVES

To identify key elements in the recognition and management of a patient with an orbital blowout fracture and make recommendations on diagnosis, treatment, referral, imaging, and return to sports.

BACKGROUND

Orbital blowout fractures are uncommon but important injuries for physical therapists to recognize. Immediate management is essential in preventing complications. The mechanism of injury is a direct blow to the orbital rim or orbit.

CASE DESCRIPTION

The patient reported to the athletic training room 15 minutes after completing a boxing match and reported that his left eye had suddenly inflated after blowing his nose. We suspected an orbital blowout fracture and referred him immediately to the emergency department where conventional radiographs were ordered. On follow-up the next day, after determining that the radiographs were normal, but still having a high index of suspicion for an orbital blowout fracture, we referred him to his primary care manager. The primary care manager ordered a computed tomography scan that revealed the fracture and referred the patient to ophthalmology.

OUTCOMES

The patient was restricted from the remaining 4 weeks of the boxing season. He completed a rigorous Army physical fitness test 7 days postinjury and the Marine Corps Marathon 47 days postinjury.

DISCUSSION

Orbital blowout fractures without double vision, extraocular muscle entrapment, or persistent numbness can be treated with time and protection. The patient can continue with normal fitness activities except contact or collision sports.

The Effect of Striking Angle on the Buckling Mechanism in Blowout Fracture

BACKGROUND

The buckling mechanism is widely accepted as a mechanism of blowout fractures, along with the hydraulic mechanism. Although many studies have been performed related to the buckling mechanism, none of them have taken the direction of the striking force into consideration. As the orbital floor is not parallel to the horizontal plane, a difference in the striking force direction might affect resultant fracture patterns. The present study aims to investigate whether fracture patterns in the orbital floor were influenced by the striking force direction in terms of the buckling mechanism.

METHODS

The authors produced three-dimensional models on a workstation simulating eight dry skulls and applied striking forces on the orbital rim of each model from three different angles (0, 15, and 30 degrees in the upward direction). Using finite element analysis, the authors calculated the width of the area where the resultant stresses exceed the bone's yielding criterion. The width was termed the "theoretical fracture width" because, theoretically, fracture was expected to occur in the area. Then, the authors compared the theoretical fracture width in groups with the three different striking force angles. Finally, the validity of the theoretical width was verified with an experiment on actual skull models.

RESULTS

The theoretical fracture width was the greatest when the striking force was directed at 30 degrees in the upward direction.

CONCLUSIONS

For the buckling mechanism, fracture would occur in a wider area of the orbital floor when striking force was directed upward than when the force was horizontally directed. This finding would be helpful in predicting fracture width in blowout fractures.

[Reconstruction of orbital floor defect with polylacticglycolide acid/recombinant human bone morphogenetic protein 2 compound implanted material in sheep]

OBJECTIVE

To study the effect and safety of polylacticglycolide acid copolymer (PLGA) and recombinant human bone morphogenetic protein 2 (rhBMP-2) as implanted biomaterials for reconstruction orbital floor defects in sheep and find the relationship between implant materials degradation and orbital floor defects restoration.

METHODS

Nine sheep (eighteen eyes) with orbital floor defect were divided into three groups randomly. Group A was the control without treatment. Group B was treated with PLGA and group C was received PLGA/rhBMP-2. Cosmetic appearances and complications were observed after surgery. CT scan, 3D reconstruction, defect area measurement and histological examination were performed on a week, three months and six months after operation.

RESULTS

No complication was observed. The CT examinations showed that orbital floor defect in group C was almost disappeared by six months, however in group A and group B only partially orbital floor defect was repaired. Histological examinations showed that all materials were absorbed on six months. The orbit defects in group A were replaced by fiber tissue. The defect areas in group B were consisted of bone tissue in the peripheral and fiber tissue in the center. In group C the reconstructed areas were replaced by bone tissue, loose connective tissue and mucosal epithelia layers.

CONCLUSION

The thick of 0.5 mm PLGA/rhBMP-2 sheet is a good substitute material of bone graft and may be used for orbital fracture defect reconstruction in clinic in the future.

Buckling and Hydraulic Mechanisms in Orbital Blowout Fractures

Since the first description of orbital blowout fractures, there has been much confusion as to their etiology. Two principal mechanisms have been proposed to explain their production, the buckling and the hydraulic mechanisms caused, respectively, by trauma to the orbital rim and the globe of the eye. The aim of this study was to evaluate both mechanisms qualitatively and quantitatively. Our protocol used intact cadavers, quantifiable intraocular pressure, variable and quantifiable force, and quantifiable bone strain distribution with strain gauge analysis. One orbit of each cadaver was used to simulate each of the two mechanisms, allowing direct comparison. Fractures produced by the buckling mechanism were limited to the anterior part of the orbital floor, with strain readings reaching up to 3756 microepsilon. Posteriorly, strain did not exceed 221 microepsilon. In contrast, hydraulic-type fractures were much larger, involving anterior and posterior parts of the floor as well as the medial wall of the orbit. Here, strain exceeded 3756 microepsilon in both parts of the floor. Furthermore, we have demonstrated that the average energy required to fracture the orbital floor by the buckling mechanism is 1.54 J, whereas an average energy of 1.22 J is needed to produce this fracture by the hydraulic mechanism. Our results suggest that efforts to establish one or another mechanism as the primary etiology are misplaced. Both mechanisms produce orbital blowout fractures, with different and specific characteristics. We believe this provides the basis for our reclassification of such fractures.

Assessment of biomechanics of orbital fracture: a study in goats and implications for oculoplastic surgery in humans

PURPOSE

To determine the biophysical characteristics of energy absorption of the various orbital structures and the amount of force/energy required to produce an orbital fracture in goats, and to interpret results in terms of human clinical applicability.

DESIGN

Experimental animal study.

METHODS

The energy required to fracture the orbit on direct globe impact was measured. We used a variety of other measurements, including high-speed videography, intraocular pressure, and intraorbital pressure measurements to describe the biophysics of floor fracture. Twenty-one goats and 42 orbits were studied in this single institutional site study.

RESULTS

Our measurements determined the fracture threshold for the caprine orbit averaged 26.5 N (SE 3.1 N) with a total energy threshold for fracture of 2600 mJ (SE 280 mJ). Eye deformation measured 6 mm with deformation energy dissipation measuring 100 to 180 mJ (SE 10 mJ). Eye displacement measured 10 mm with dissipation measuring 50 to 75 mJ (SE 4.0 mJ). The deconvoluted bone fracture energy averaged 2350 mJ (SE 260 mJ).

CONCLUSIONS

Impact energy applied to the orbit through the eyeball is absorbed and dissipated by three primary mechanisms: (1) globe deformation, (2) globe displacement, and (3) orbital fracture. Excess energy (above the energy required for deformation and displacement) >or=2350 mJ will result in an orbital fracture.

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.

Penetrating orbitocranial gunshot injuries

BACKGROUND

The aim of this study was to analyze the effect of a surgical management protocol and other important clinical features on the prognosis of patients who had penetrating orbitocranial gunshot injuries.

METHODS

Thirty-five patients (30 unilateral, 5 bilateral) who had penetrating orbitocranial gunshot injuries were analyzed. The wounds were mainly caused by shrapnel fragments or bullets. Craniotomy was the standard treatment in all patients. Investigated clinical features included Glasgow Coma Scale (GCS) score on admission, the mode and the extent of brain injury, and the presence of an intracranial retained foreign body. The prognostic importance of complications such as infection, intracranial hemorrhage, cerebrospinal fluid leak, and epileptic seizures was also investigated. The mechanism and the injury characteristics of the patients were evaluated by predicting the visual outcome of the victims according to a newer classification system as well as other variables pertinent to this specific clinical setting of severe eye trauma. Final visual acuities of the patients were also measured.

RESULTS

The outcome of 35 penetrating orbitocranial gunshot injured patients was as follows: death in 3 patients, vegetative state in 1, severe disability in 2, moderate disability in 2, and good recovery in 27 cases. Localization and extent of the injury and GCS score on admission were the most important indicator for good neurological outcome. The predictors for good visual outcome were type B, grade 1, zone I, and relative afferent pupillary defect-negative injuries. The predictors for poor outcome were type A, grade 5, zone III, and relative afferent pupillary defect-positive injuries.

CONCLUSION

The prognosis of the injury depends on the course of the bullet or shrapnel fragment and the interdisciplinary care. An extensive preoperative evaluation of penetrating orbital trauma and a combined ophthalmic and neurosurgical approach are recommended to minimize the morbidity of the patients. However, complete removal of the foreign material in a deep or ventricular localization is not mandatory because careful debridement and tight closure of dura provides desired outcome. Evaluation of trauma mechanism and injury characteristics according to the Ocular Trauma Classification System seems to predict accurately the visual outcomes in this series.

Orbital fractures in sport: a review

Orbital fractures represent a small proportion of sports-related injuries in the US and abroad. However, the significant functional and cosmetic sequelae of such fractures warrant a comprehensive evaluation of any athlete sustaining facial trauma. Initial evaluation is directed at excluding neurological impairment or the presence of vision-threatening injury. Subsequent examination should ascertain the presence of signs and symptoms consistent with orbital fracture. These include gross bony deformity, limitation of gaze, diplopia and malposition of the globe. The presence of any of the aforementioned symptoms should prompt further investigation using computed tomography to corroborate or refute clinical suspicion. Orbital fracture mandates referral to an ophthalmologist or oculoplastic surgeon; initial management is dictated by the severity of functional symptoms, and may necessitate early surgical intervention. Those patients who are managed conservatively should return for frequent follow-up, as progressive diplopia, enophthalmos, or gaze limitation are indications for late operative repair. The majority of patients who sustain orbital fractures are able to return to sport, however, persistent diplopia is not uncommon, and may persist despite optimal treatment.

Growing skull fracture of the posterior cranial fossa and of the orbital roof

BACKGROUND

Growing Skull Fractures (GSF) are rare complications of head trauma, primarily reported in infancy and early childhood. GSF are commonly located on calvaria, and rarely in other locations, including the skull base.

METHOD

In this study, we report two cases of GSF occurring in unusual locations. The first, a 8-month old girl, with a GSF of the suboccipital posterior fossa region, and the second, a 4-year old boy with a GSF of the right orbital roof. Both cases underwent operative treatment of the GSF, with microsurgical dissection and excision of the protruding gliotic brain tissue, watertight duraplasty and autologous bone cranial repair. The authors conducted a Medline search of the relevant English literature from 1966 to 2002.

FINDINGS

From the search, three cases of suboccipital posterior fossa region GSF and twelve series of orbital GSF, describing a total of 22 cases, have been found.

INTERPRETATION

A survey of the pathogenic mechanisms underlying this entity in these locations is reported. A review of suboccipital posterior fossa and orbital roof GSF cases, of nosological, ophthalmological and neurological data, neuroradiological and operative findings, and results of different treatment strategies are described.

Strain gauge biomechanical evaluation of forces in orbital floor fractures

Since the first description of orbital blow-out fractures, there has been much confusion as to their aetiology. Two principal mechanisms have been proposed to explain these fractures, the buckling and hydraulic mechanisms, caused by trauma to the orbital rim and the globe of the eye, respectively. Previous experimental and clinical studies have aimed to support one or other of these two theories. However, these studies have failed to provide quantifiable data to objectively support their conclusions. We present the results of a study of these two proposed mechanisms under identical conditions, using quantifiable intraocular pressure, variable and quantifiable force, and quantifiable bone strain distribution with strain gauge analysis in fresh intact human post-mortem cadavers. Both qualitative and quantitative findings suggest that efforts to establish one theory over the other as the primary mechanism have been misplaced. Both mechanisms produce orbital floor fractures, although these fractures differ fundamentally in their size and location. We have objectively demonstrated that it is easier to fracture the orbital floor by the hydraulic mechanism than by the buckling mechanism, and provided quantitative data for the average force required to displace the orbital floor.

Growing-fracture of the orbital roof with post-traumatic encephalocele in an adult patient. Case report

Growing fractures are a rare entity, usually occurring in paediatric age. Localisation at the orbital region is even rarer. We report the case of a growing fracture of the orbital roof with post-traumatic encephalocele in an adult patient, the 1(st) similar case in adulthood at our knowledge. Clinical and neuroimaging aspects are described, underlining the role of MRI in displaying intraorbital encephalocele. Surgical treatment with relevant technical notes is discussed as well.

The sphenozygomatic suture as a key site for osteosynthesis of the orbitozygomatic complex in panfacial fractures: a biomechanical study in human cadavers based on clinical practice

The aims of this study were to determine the forces required for fracturing the intact orbitozygomatic complex and to evaluate the strength of the orbitozygomatic complex-fixation, especially with regard to the sphenozygomatic suture as a fixation point. In severe midfacial and panfacial fractures, the sphenozygomatic suture is routinely used in the authors' practice as a key site for fixation of the orbitozygomatic complex, thus establishing a stable outer frame as a basis for subsequent reconstruction. However, this has never been formally described, nor has it been biomechanically tested. Eight human cadaver heads were subjected to forces applied in a standard fashion to the orbitozygomatic complex on both sides (n = 16) using a servohydraulic testing machine. The force required to break the intact orbitozygomatic complex was measured on both sides. Subsequently, fracture patterns were noted and each orbitozygomatic complex (n = 16) was assigned to one of four groups: four-point fixation (zygomatic arch, frontozygomatic suture, infraorbital rim, zygomaticomaxillary buttress) using a 1.3/2.0-mm titanium system (group 1) and a 2.0-mm bioresorbable system (group 3); or three-point fixation (zygomatic arch, frontozygomatic suture, sphenozygomatic suture) using 1.3/2.0-mm titanium system (group 2) and a 2.0-mm bioresorbable system (group 4). Forces for failure of the constructs were measured. The force for failure of the intact orbitozygomatic complex was 1826 +/- 852 N. The mean force required for failure of the reconstructed orbitozygomatic complex was 504 +/- 178 N for group 1, 620 +/- 304 N for group 2, 93 +/- 22 N for group 3, and 133 +/- 31 N for group 4. The titanium constructs provided 27.7 percent (four-point fixation) and 31.7 percent (three-point fixation) of the intact breaking strength of the orbitozygomatic complex, which was significantly higher (p < 0.05) compared with 5.4 percent (four-point fixation) and 7.7 percent (four-point fixation) for the bioresorbable system. Plate bending (91 percent) was the primary cause for failure in the titanium plating system, whereas plate and screw breakage (57 percent) was responsible for failure of the resorbable system. The fixation of the sphenozygomatic suture was a key site in the fixation of the orbitozygomatic complex, which could be demonstrated with superior results in the three-point fixation group compared with the four-point fixation group. The bioresorbable system showed the lowest values in this cadaver study. Further experimental and clinical studies might determine whether the bioresorbable materials are sufficient for the treatment of complex fractures of the orbitozygomatic complex.

Orbital blowout fractures: experimental evidence for the pure hydraulic theory

BACKGROUND

The mechanism of injury and the underlying biomechanics of orbital blowout fractures remain controversial. The "hydraulic" theory proposes that a generalized increased orbital content pressure results in direct compression and fracturing of the thin orbital bone.

OBJECTIVE

To examine the pure hydraulic mechanism of injury by eliminating the factor of globe-to-wall contact and its possible contribution to fracture thresholds and patterns.

MATERIALS AND METHODS

Five fresh human cadaver specimens were used for the study. In each cadaver head, 1 orbit was prepared to mimic the normal physiologic condition by increasing the hypotony of the cadaver globe to normal intraocular pressure (15-20 mm Hg) with intravitreous injection of isotonic sodium chloride solution (saline). The second orbit served as a "hydraulic control," whereby the globe and orbital contents were exenterated and replaced by a saline-filled balloon at physiologic intraocular pressure. A 1-kg pendulum measuring 2.5 cm in diameter was used to strike the cadaver heads. Drop heights ranged from 0.2 m to 1.1 m (1960 mJ to 10 780 mJ energy). Each head was struck twice, once to each orbit. Direct visualization, high-speed videography, and computed tomographic scans were used to determine injury patterns at various heights between the 2 orbits.

RESULTS

A fracture threshold was found at a drop height of 0.3 m (2940 mJ). Fracture severity and displacement increased with incremental increases in drop height (energy). Fracture displacement, with herniation of orbital contents, was obtained at heights above 0.5 m (4900 mJ). Isolated orbital floor fractures were obtained at lower heights, with medial wall fractures occurring in conjunction with floor fractures at higher energies (> or =6860 mJ). The globe intact side and balloon (hydraulic control) side showed nearly identical fracture patterns and levels of displacement at each drop height.

CONCLUSIONS

This study provides support for the "hydraulic" theory and evidence against the role of direct globe-to-wall contact in the pathogenesis of orbital blowout fractures. In addition, the orbital floor was found to have a lower threshold for fracture than the medial wall. Preliminary threshold values for fracture occurrence and soft tissue displacement were obtained.

Infraorbital nerve recovery after minimally dislocated facial fractures

There is evidence that rigid fixation of zygomaticomaxillary suture enhances the recovery of the infraorbital nerve compared with other means of surgical treatments. There is, however, no agreement as to whether any surgery decreases the number of sensory disturbance in cases with little or no dislocation, or whether infraorbital numbness alone should be considered an indication for surgery. An operation may even increase the edema and hemorrhage around the nerve. This retrospective study was carried out among patients with infraorbital hypesthesia but little or not at all dislocated midfacial fractures. Two special types of trauma patients were selected; those with a blow-out fracture but an intact infraorbital rim (BO) and those with a zygomaticomaxillary complex fracture (ZMC). A questionnaire was sent to the patients (n = 226) 2.2 years (mean) after the accident. There were 128 responses (BO n = 41, ZMC n = 87). Of these, 27 BO and 29 ZMC patients had been treated by observation. An orbital exploration had been carried out in 14 BO patients, and 58 ZMC patients had received malar bone elevation without rigid fixation. At the end of the follow-up period nontreated patients had fewer symptoms than those who had had surgery. This was clearer in the ZCM group (symptom free 69% vs. 52%) than in the BO group (69% vs. 50%). The differences between surgically and nontreated BO or ZMC patients, however, were statistically nonsignificant. According to our findings, exploration of the orbital floor or an attempted elevation of a minimally or nondislocated fracture of the ZMC does not enhance the recovery of the infraorbital nerve. On the contrary, the procedure may itself increase the morbidity and sensory dysfunction. Further studies are needed to determine whether the results could be improved by selective decompression of the infraorbital nerve and a rigid fixation.

The diagnosis and management of orbital blowout fractures: update 2001

A cogent update of orbital blowout history, anatomy, and management are included with a retrospective study of 59 pure orbital blowout fractures which occurred between 1994 and 1998. Our goal is to provide a better understanding of this frequently encountered entity and to help augment the confidence of nonophthalmologists who will often evaluate patients with suspected orbital blowout fractures.

Diagnosis and management of posttraumatic oculorrhea

Posttraumatic cranio-orbital cerebrospinal fluid (CSF) fistula is very rare. Diagnosis of these fistulas may be difficult, and it is possible that this complication of craniofacial injury is underdiagnosed. Early recognition and adequate treatment is of paramount importance to prevent hazardous complications. The authors report the case of a 20-year-old woman in whom a CSF leak developed through the medial canthus area of her eye after she sustained a mild sports-related injury. Clinical examination and chemical analysis of the fluid led to the correct diagnosis, and the leak was stopped with conservative treatment. It is proposed that a CSF leak through the eye be termed “oculorrhea” as compared with otorrhea and rhinorrhea. The mechanism of the fistula in this patient is discussed, as is the pertinent radiologically demonstrated anatomy and the mechanism of injury. Management and controversies are also discussed.

Mechanisms of orbital floor fractures: a clinical, experimental, and theoretical study

PURPOSE

The purpose of this study was to investigate the two accepted mechanisms of the orbital blowout fracture (the hydraulic and the buckling theories) from a clinical, experimental, and theoretical standpoint.

METHODS

Clinical cases in which blowout fractures resulted from both a pure hydraulic mechanism and a pure buckling mechanism are presented. Twenty-one intact orbital floors were obtained from human cadavers. A metal rod was dropped, experimentally, onto each specimen until a fracture was produced, and the energy required in each instance was calculated. A biomathematical model of the human bony orbit, depicted as a thin-walled truncated conical shell, was devised. Two previously published (by the National Aeronautics and Space Administration) theoretical structural engineering formulas for the fracture of thin-walled truncated conical shells were used to predict the energy required to fracture the bone of the orbital floor via the hydraulic and buckling mechanisms.

RESULTS

Experimentally, the mean energy required to fracture the bone of the human cadaver orbital floor directly was 78 millijoules (mJ) (range, 29-127 mJ). Using the engineering formula for the hydraulic theory, the predicted theoretical energy is 71 mJ (range, 38-120 mJ); for the buckling theory, the predicted theoretical energy is 68 mJ (range, 40-106 mJ).

CONCLUSION

Through this study, we have experimentally determined the amount of energy required to fracture the bone of the human orbital floor directly and have provided support for each mechanism of the orbital blowout fracture from a clinical and theoretical basis.

Correlation of preoperative computed tomography and postoperative ocular motility in orbital blowout fractures

PURPOSE

To determine a relationship between preoperative soft tissue disruption and postoperative ocular motility in orbital blowout fractures.

METHODS

This retrospective cohort study reviewed 30 patients who met all criteria: retrievable coronal computed tomography (CT) scans; internal fractures of the orbital floor, with or without medial wall extension; preoperative diplopia; repair by a single surgeon; complete release of entrapped tissues; and postoperative binocular visual fields (BVFs). Motility outcomes were quantified by one group of the authors, who measured the vertical fusion within BVFs. Other authors analyzed CT scans, designating each fracture as either A or B, based on lesser or greater soft tissue distortion relative to the configuration of bone fragments. The interval between trauma and surgery was also determined.

RESULTS

Among the 15 patients with a postoperative motility outcome poorer than the median (86 degrees or less), four (27%) had A fractures; 11 (73%) had B fractures. Among the 15 patients with an outcome better than the median (88 degrees or more), 10 (67%) had A fractures; five (33%) had B fractures. Differences were more defined away from the median. Among five patients with B fractures and better than the median result, three (60%) had surgical repair during the first week after injury. Among the 11 patients with B fractures and less than the median result, one (9%) had repair during the first week.

CONCLUSIONS

Postoperative motility is influenced by soft tissue-bone fragment relationships. Whether the outcome can be altered by earlier surgery in selected cases will be determined by prospective studies.

Real-time interactive MR imaging system: sequence optimization, and basic and clinical evaluations

A real-time interactive MR imaging system (real-time MRI) is an MR scanner which has a fast image updating cycle and the ability to freely change slice orientation, just like an ultrasound imaging system. Recently, such a system has been developed and installed on a clinical 1.5-Tesla system. The purpose of this study was to optimize the pulse sequences for clinical use and to evaluate the clinical usefulness and basic functionality of real-time MRI. For T1-weighted imaging, FLASH (fast low angle shot) can be selected, and up to 5 frames per second can be acquired depending on the matrix size. For T2-weighted imaging, true FISP (fast imaging with steady-state precession) can be selected, and up to 4 frames per second can be acquired. Maximum C/N between liver and spleen was obtained at a flip angle of 20 degrees on FLASH. Maximum C/N between cardiac cavity and wall was obtained at a flip angle of 60 degrees on true FISP. Localization of the right and left coronary arteries could be performed within 30 seconds in three volunteers. Although the present real-time MRI system has drawbacks such as low spatial resolution and relatively low contrast resolution, we expect real-time MRI to be one of the most important tools for future clinical MRI.

Randomized prospective study of the influence of steroids on postoperative eye-opening after exploration of the orbital floor

OBJECTIVE

To find out if giving steroids reduces postoperative swelling in orbital surgery.

DESIGN

Prospective, randomized, double-blind trial.

SETTING

Regional unit, teaching hospital, UK.

SUBJECTS AND INTERVENTIONS

20 patients who require orbital floor exploration after injuries. Patients were given methylprednisolone 250 mg (or placebo identically packaged) at induction of anaesthesia, with a further three doses at 6-hourly intervals postoperatively.

MAIN OUTCOME MEASURE

Differences in interpalpebral width before and after operation.

RESULTS

Those given steroids (n=11) had a significantly increased interpalpebral width compared with placebo (n=9) postoperatively (P < 0.01, 95% confidence intervals of the difference = 1 mm-6 mm).

CONCLUSION

Short courses of steroids therapy should be considered in orbital surgery for appropriate patients. There is an advantage in being able to assess the globe postoperatively.

Intraocular and intraorbital compartment pressure changes following orbital bone grafting: a clinical and laboratory study

Visual loss is an uncommon but catastrophic complication after intraorbital bone grafting for the reconstruction of acute traumatic defects or long-standing enophthalmos. Increased intraocular or intraorbital compartment pressure may be pathogenic in this setting. A two-part study was designed to test the null hypothesis that intraocular and intraorbital compartment pressure values remain constant despite orbital volume reduction with graft material. Laboratory study: Intraocular and intraorbital compartment pressures were measured during sequential orbital volume reduction in New Zealand White rabbits that had been randomized to one of three groups: intact orbits (n = 10), acute orbital wall defects (n = 8), and chronic (3 months) orbital wall defects (n = 11). Intraocular pressure was significantly (p<0.05) elevated in all three groups of orbits undergoing orbital volume reduction compared with control, nonoperated orbits. Intraorbital compartment pressure values did not change significantly from control levels throughout the grafting sequence. Although no significant differences existed between groups in the maximum levels of intraocular pressure attained, the chronic group demonstrated a greater rate of rise and slower rate of decline. Clinical study: Using applanation tonometry, intraocular pressure was measured before and serially after orbital floor exploration and intraorbital placement of split calvarial bone grafts in 19 patients who presented with orbital-zygomatic complex fractures that required surgery. A separate group of 16 patients with orbital-zygomatic complex fractures that required exploration of the orbital floor but not bone grafting was used for comparison. A significant (p<0.05) elevation of intraocular pressure was observed immediately after bone grafting compared with nongrafted orbits, but values returned to normal within 30 minutes and remained stable through the third postoperative day. There were no cases of visual impairment in any patients in either group as the result of surgical treatment. These data indicate that orbital volume reduction with graft material results in significant, temporary elevation of intraocular pressure. No significant elevations of intraorbital compartment pressure were detected in the rabbit orbits. Data from this study may have direct relevance in defining guidelines for "tolerable" changes in orbital tissue and globe pressures after surgery.

A biomechanical analysis of the orbitozygomatic complex in human cadavers: examination of load sharing and failure patterns following fixation with titanium and bioresorbable plating systems

The orbitozygomatic complex (OZC) and zygomatic arch act as key buttresses in the restoration of midfacial projection and width in the treatment of panfacial fractures, yet little is known about the biomechanical and deformational forces placed on this region under applied load conditions. The aims of this project were (1) to study the stress-force relationships and load sharing of the intact human OZC under subfailure loads, (2) to assess load sharing and breaking strength of the OZC when intact and after four-point miniplate fixation with either titanium (1.2 and 1.7 mm) or bioresorbable (1.5 and 2.0 mm) systems, and (3) to analyze failure patterns. Using the MTS machine, fresh frozen human skulls stripped of soft tissue underwent loading with subfailure and failure forces directed in a standard fashion. Electrical resistance gauges applied directly to local and remote bony buttresses demonstrated temporary deformation at local (zygomatic arch, lateral and inferior orbital rim) and remote (supraorbital rim) buttresses under subfailure loading conditions. Breaking strength of the OZC (N = 10) measured before and after four-point application of 1.2- or 1.7-mm titanium or 1.5- or 2.0-mm bioresorbable miniplates demonstrated a significant (p < 0.05) decrease compared with intact controls. Surprisingly, the 2.0-mm bioresorbable miniplate construct provided only 13% of the intact breaking strength of the OZC compared with 39% for the 1.7-mm titanium system (p < 0.05). Plate bending or breakage was responsible for failure of the OZC following rigid fixation. Biomechanical testing of the OZC demonstrates (1) load sharing at regional and remote bony buttresses, (2) significant decreases in breaking strength following miniplate fixation, and (3) deformation of miniplates as a primary cause of failure under load conditions. Data generated from this project may be useful with regard to optimizing fixation of the OZC in the context and treatment of panfacial fractures.

Mechanisms of extraocular muscle injury in orbital fractures

The gross and microscopic events that occur after orbital blowout fractures were evaluated to assess the mechanisms of diplopia and muscle injury. Intramuscular and intraorbital pressures were evaluated in experimental animals, in cadavers, and at the time of orbital fracture explorations for repair of orbital fractures in humans. Histologic and circulatory changes, muscle pressure recordings, and operative observations were evaluated. Creation of a compartment syndrome was evaluated to include a histologic evaluation of the orbital fibrous sheath network for the extraocular muscles and the intramuscular vasculature. These experiments and observations do not support the role of a compartment syndrome in ocular motility disturbances because (1) intramuscular pressures were subcritical in both humans and animals; (2) no limiting fascial compartment could be demonstrated; and (3) microangiograms and histologic evaluations did not confirm areas of compartmental ischemic necrosis. Muscle contusion, scarring within and around the orbital fibrous sheath network, nerve contusion, and incarceration within fractures remain the probable causes of diplopia, with the most likely explanations being muscle contusion and fibrosis or incarceration involving the muscular fascial network.

Management of displaced lateral orbital wall fractures associated with visual and ocular motility disturbances

Impacted fractures of the lateral orbital wall are a type of orbital blow-in fracture that may be accompanied by decreased visual acuity and ocular motility limitations. Eleven patients who suffered this injury triad were retrospectively reviewed to determine the nature of the ophthalmologic injuries and the effect of fracture reduction on recovery of ophthalmologic functions. Two patients with decreased visual acuity owing to trauma to the globe recovered to subjective pretrauma levels following surgery. Nine patients were thought to have a traumatic optic neuropathy with varying degrees of visual loss. Patients with an injury to the intraorbital portion of the optic nerve and a presurgical visual acuity of 20/400 or better recovered to subjective pretrauma levels. Those with visual acuity of less than 20/400 or an injury to the intracanalicular portion of the nerve had responses ranging from no improvement to objective improvement with large field defects. Ocular motility improved in all patients, many in the immediate postsurgical period consistent with removal of a mechanical restriction. No patients had worsening of ophthalmologic deficits as a result of manipulation of fracture fragments. Our experience suggests that early surgical intervention facilitates recovery of vision and eye movement. The traumatic optic neuropathy that accompanies this fracture is distinct from the indirect type of optic nerve injury that may respond to steroids, and the ophthalmoplegia is distinct from the usual traumatic superior orbital fissure syndrome that resolves spontaneously. An understanding of the impacted lateral orbital wall fracture and its ophthalmologic implications is essential for any surgeon who desires to manage craniomaxillofacial injuries.

An unusual variant of a growing skull fracture in an adolescent

A great majority of growing skull fractures occur in infancy and earlychildhood. Since the growth of brain is necessary as a driving force for these lesions to occur, almost all reported cases have been before the first 3 years of life. Although a number of uncommon locations, such as basiooccipital and skull base areas, have been reported, they are commonly located on calvaria. The authors report a growing skull fracture on the orbital roof in a 16-year-old female admitted to hospital with complaints of headache and seizures. She had had an orbital trauma 8 years before. CT scan revealed a hypodense lesion in the right frontal lobe and a diastatic fracture line on the right orbital roof. A right craniotomy was performed. Excision of arachnoid loculations and duraplasty were carried out. This is an unusual condition with respect to the location of the lesion, as well as the age of the patient.

Orbital blow-out fractures: correlation of preoperative computed tomography and postoperative ocular motility

BACKGROUND/PURPOSE

Although the management of orbital blow-out fractures was controversial for many years, refined imaging with computed tomography (CT) helped to narrow the poles of the debate. Many orbital surgeons currently recommend repair if fracture size portends late enophthalmos, or if diplopia has not substantially resolved within 2 weeks of the injury. While volumetric considerations have been generally well-served by this approach, ocular motility outcomes have been less than ideal. In one series, almost 50% of patients had residual diplopia 6 months after surgery. A fine network of fibrous septa that functionally unites the periosteum of the orbital floor, the inferior fibrofatty tissues, and the sheaths of the inferior rectus and oblique muscles was demonstrated by Koornneef. Entrapment between bone fragments of any of the components of this anatomic unit can limit ocular motility. Based on the pathogenesis of blow-out fractures, in which the fibrofatty-muscular complex is driven to varying degrees between bone fragments, some measure of soft tissue damage might be anticipated. Subsequent intrinsic fibrosis and contraction can tether globe movement, despite complete reduction of herniated orbital tissue from the fracture site. We postulated that the extent of this soft tissue damage might be estimated from preoperative imaging studies.

METHODS

Study criteria included: retrievable coronal CT scans; fractures of the orbital floor without rim involvement, with or without extension into the medial wall; preoperative diplopia; surgical repair by a single surgeon; complete release of entrapped tissues; and postoperative ocular motility outcomes documented with binocular visual fields (BVFs). Thirty patients met all criteria. The CT scans and BVFs were assessed by different examiners among the authors. Fractures were classified into 3 general categories and 2 subtypes to reflect the severity of soft tissue damage within each category. "Trap-door" injuries, in which bone fragments appeared to have almost perfectly realigned, were classified as type I fractures. In the I-A subtype, no orbital tissue was visible on the sinus side of the fracture line. In the I-B subtype, soft tissue with the radiodensity of orbital fat was visible within the maxillary sinus. In type II fractures, bone fragments were distracted and soft tissue was displaced between them. In the II-A subtype, soft tissue displacement was less than, or proportional to, bone fragment distraction. In the II-B subtype, soft tissue displacement was greater than bone fragment distraction. In type III fractures, displaced bone fragments surrounded displaced soft tissue in all areas. In the III-A subtype, soft tissue and bone were moderately displaced. In the III-B subtype, both were markedly displaced. Motility outcomes were quantified by measuring the vertical excursion in BVFs. The interval between trauma and surgical repair was also determined.

RESULTS

Among the 15 patients with a motility outcome in BVFs which was poorer than the median (86 degrees or less of single binocular vertical excursion), 4 patients (27%) had type A fractures; 11 patients (73%) had type B fractures. Among the 15 patients with a better outcome than the median (88 degrees or more), 10 patients (67%) had type A fractures; 5 patients (33%) had type B fractures. These differences became more defined as analysis moved away from the median. Among 5 patients with type B fractures and better than the median result in BVFs, 3 patients (60%) had surgical repair during the first week after injury. Among the 11 patients with type B fractures and less than the median result, 1 patient (9%) had repair during the first week.

CONCLUSIONS

When the CT-depicted relationship between bone fragments and soft tissues is considered, a wide spectrum of injuries is subsumed under the rubric of blow-out fractures. In general, greater degrees of soft tissue incarceration or displacement, with presumably greater intrinsic damage and subsequent fibrosis, appear to result in poorer motility outcomes. Although this retrospective study does not conclusively prove its benefit, an urgent surgical approach to selected injuries should be considered.

Early and delayed repair of orbitozygomatic complex fractures

PURPOSE

The goal of this study was to review experience with early and delayed repair of orbitozygomatic complex fractures and develop guidelines for repair based on timing and extent of injury.

PATIENTS AND METHODS

Records of patients with orbitozygomatic complex fractures over a 10-year period were reviewed for cause of injury, signs and symptoms, length of time from injury to repair, and method of repair. Results were evaluated by office examination and telephone interviews at least 6 months to 10 years after surgery.

RESULTS

Seventy-eight patients who had undergone 81 surgical procedures were analyzed. The series consisted of 49 primary repairs (1 to 22 days postinjury), 10 delayed repairs using osteotomies at 21 days to 5 months postinjury, and 22 delayed repairs requiring onlay bone grafting from 4 months to 16 years postinjury. Forty patients (43 procedures) were available for follow-up. Early surgical intervention dramatically improved esthetic and functional outcomes, whereas late repair was less satisfactory. Hypoesthesia was not improved by surgery. Osteotomy and onlay grafting techniques were necessary for delayed treatment.

CONCLUSION

Orbitozygomatic fractures can be repaired up to 21 days postinjury using primary reduction and fixation techniques. Osteotomies are required after 21 days and can be used successfully up to 4 months postinjury. After 4 months, successful repair requires onlay bone grafting.

Management of orbital fractures

Motor vehicle accidents have a high association with orbital injuries. A thorough clinical examination is essential, especially an ophthalmic examination. Radiographic analysis is an important aspect of diagnosis. Plain films can be obtained emergently, but high resolution CT scans with axial and coronal planes provide more accurate information. Zygomatic complex fractures are the most common injuries involving the orbits, with naso-orbito-ethmoid fractures and internal orbital fractures following. Autogenous bone, allografts, or synthetic material can be used for repair of defects located in the anterior or middle part of the orbital floor. Multi-team approach is important in the comprehensive management of these complex injuries.

[Three-dimensional finite element analysis of blowout fractures]

There are a number of theories as to how orbital fractures come about, but there are still a lot of unanswered questions regarding the dynamic characteristics of the orbit at the time of the fracture. To answer these questions, we analyzed the degree and concentration of stress within the orbit depending on the loads placed upon it. We used a computer to create a three-dimensional finite element model which could simulate the orbital fracture process. We found that direct force applied against the inferior orbital rim by forces outside the eye results in increased stress within the lower wall of the orbit, and that stress tends to concentrate in the thin nasal side of the orbital groove as pressure within the orbit mounts. When we compared these findings with clinical cases of orbital fracture, it became clear that the best way to explain the clinical data is by reference to the combined effect of direct force applied against the inferior orbital rim by elements outside the eye and the buildup of internal pressure within the orbit.

Orbital blowout fractures in sport

One-third of orbital blowout fractures are sustained during sport. Soccer is most commonly involved. Though visual acuity recovery is usually complete, permanent loss of binocular visual field is almost universal. Typically high-energy blows by opponent's finger, fist, elbow, knee or boot are responsible. Injuries to the eye itself may also be sustained and should be looked for. Ocular protection may be feasible in some sports, but the main preventive measure to be addressed is the reduction in aggressive play or deliberate injury.

[Mechanism of the formation of orbital floor fractures. Holographic interferometry studies]

To date, it has not been possible to answer the question of whether in the classic blow-out fracture the orbital floor is fractured by hydraulic force exerted by the orbital contents or by force transmission within the bony structures of the skull. The aim of our investigation was therefore to reveal the nature of orbital deformation mediated solely by the bone. In holographic interferometry the holographic image of the unstrained object is superimposed on the image of the same object after deformation. The resulting image of the object contains a pattern of interference lines representing the extent of the deformation. This image can be visualized on a TV screen after digital processing of a picture registered by a video camera. This method was used to analyze the deformation of the bony orbit by contact force applied to several points along the orbital rim (each application consisting of 1 N) and by strain distributed evenly upon the orbital rim of the human skull. In all cases maximal deformation occurred in the medial part of the orbital floor no matter where the stress was applied. This finding coincides with the fact that the majority of clinically diagnosed fractures are found in this area. In conclusion, force transmission within the bone is considered as being one determining factor for occurrence of orbital floor fractures.