The use of flash visual evoked potentials in the early diagnosis of suspected optic nerve lesions due to craniofacial trauma

Acute orbital compartment syndrome due to traumatic hemorrhage: 4-year case series and relevant literature review with emphasis on its management

PURPOSE

Blindness in craniomaxillofacial (CMF) injuries may occur due to acute orbital compartment syndrome (AOCS). Primarily, this article aimed to retrospectively review our 4-year experience in the management of patients diagnosed with AOCS secondary to an orbital hematoma (OH). Furthermore, this paper included up-to-date information regarding the prevalence, diagnosis, management, and prognosis of AOCS.

MATERIALS AND METHODS

We retrospectively screened the medical records of patients who visited our hospital's emergency department (ED) and were examined by an oromaxillofacial surgeon for CMF injuries, between September 1, 2013, and September 31, 2017. The electronic hospital's database was searched to retrieve all cases of CMF trauma admitted or referred to our clinic during this period.

RESULTS

Over a 49-month period, 3,514 patients were managed for CMF injuries in ED; 9 cases (0.26%) were attributed to OCS caused by an OH. This group comprised 5 males and 4 females aged between 32 and 91 years old (mean 65.7, median 70). Seven out of 9 patients were subjected to lateral canthotomy and inferior cantholysis (LCIC), whereas septolysis was applied in 6 of them. Sight was preserved in 3 out of 8 patients (37.5%), since a patient died from a serious intracranial injury. Seven out of 9 patients (77.7%) of the OCS group had a history of hypocoagulable state.

CONCLUSIONS

LCIC, septolysis, and careful dissection within inferotemporal orbital quadrant constitute a reliable approach for emergent orbital decompression. CT scan offers differential diagnosis of acute traumatic proptosis, but it should preferably follow LCIC. In case of OHs without pupillary abnormalities and/or impairment of visual acuity, close monitoring allowing for timely interventions is highly recommended to patients with a history of hypocoagulative status, (uncontrolled or severe) hypertension, head trauma, and decreased level of consciousness or in elderly patients suffering from dementia or without rapid access to follow-up medical care. Clinicians dealing with ED services must maintain high skills in AOCS diagnosis and in LCIC execution.

Prognosticators for Visual Outcome in Indirect Traumatic Optic Neuropathy: A Prospective Cohort Study

Introduction Traumatic optic neuropathy (TON), with indirect TON as its more prevalent form, is a dreadful cause of severe visual dysfunctions. The condition is known to have a contentious treatment plan and poor visual sequelae; hence, the assessment of prognostic signs becomes valuable. Prospective studies evaluating important predictors of visual recovery after traumatic optic nerve injury can particularly be helpful in a longitudinal observation. The possible roles of clinical variables need to be assessed. Absent visual evoked potential (VEP) records as a crucial finding associated with TON has reportedly valuable prognostic significance. This also needs to be explored. Hence, the study sought to determine the role of prognosticators in the visual outcome of the patients, with a focus on evaluating the role of VEPs in the severity and prognosis of indirect TON. Methods A prospective observational study involving 40 patients with indirect TON was conducted. Ocular, neuro-ophthalmological, radiological, and neurophysiological variables, including flash VEP, were investigated at their initial visit and followed up until the end of six months. Final visual acuity was the primary outcome variable studied. Paired t-test was used to perform the comparison between the flash VEP variables for normal and affected eyes at the initial visit. Pearson correlation coefficient was computed for obtaining the association of initial visual acuity and flash VEP variables with the outcome variable. Relative risk was calculated and analysed for the prognosticators in univariate analysis. Statistical significance was defined as p < 0.05. Results Statistically significant variations in mean P100 latency, N75-P100, and P100-N145 amplitudes compared between normal and affected eyes in the patients at the initial visit were obtained (p < 0.0001; paired t-test). Pearson correlation coefficient for initial visual acuity and flash VEP variable as independent variables and final visual acuity as the dependent variable were statistically significant (p < 0.05). The relative risks for prognosticators with a statistically significant range of confidence intervals were poor initial visual acuity, greater relative afferent pupillary defect (RAPD) grades, deranged flash VEP variables (absent VEP, reduction in amplitude ratio (>50%), and increased interocular latency differences), loss of consciousness during injury, age greater than 40 years, and lack of improvement after 48 hours of steroid treatment. Conclusion The identified negative prognosticators may be helpful in deciding the kind of therapeutic approach and predicting the visual outcome in patients with indirect TON.

Factors Affecting Optic Nerve Damage in Le Fort III Osteotomy: A Retrospective Study

The causes of visual impairment following Le Fort osteotomy for syndromic craniosynostosis have not been completely elucidated. The authors investigated the potential causes and means of prevention of optic nerve damage, with particular emphasis on intraoperative blood transfusion volume and operating time. This retrospective study evaluated patients who underwent Le Fort III osteotomy for syndromic craniosynostosis between 2000 and 2020. Data on pupillary reflex, pupil size, operating time, blood transfusion, age at time of surgery, sex, and syndrome type were obtained from medical records. Univariate analysis and multivariate analysis with the level of statistical significance set at P<0.05. For the 86 patients included, the mean values of operating time, amount of blood transfusion based on body weight, amount of blood transfusion per body weight per hour, and age were 6.0 hours (range: 3.5-12.3 h), 30.5 mL/kg (range: 0-322 mL/kg), 5.14 mL/kg/h (range: 0-35.7 mL/kg/h), and 10.0 years (range: 4-38 y), respectively. Crouzon, Apert, and Pfeiffer syndromes were observed in 49, 29, and 8 patients, respectively. Abnormal pupillary findings were observed in 27 patients of whom 25 showed no abnormalities in subsequent visual function and 2 developed blindness. Abnormal pupillary findings correlated with the amount of blood transfused per body weight (P=0.0082) and amount of blood transfused per body weight per hour (P=0.0052). As demonstrated in this study, increased intraoperative bleeding and amount of blood transfused were associated with optic nerve damage, particularly during acute bleeding. Prompt inspection of the pupils following surgery is therefore warranted.

Use of custom fabricated surgical jig to improve surgical outcomes in open reduction internal fixation of unilateral orbital fractures: A prospective clinical study

PURPOSE

The aim of the study was to assess the efficacy of virtual planning and surgical guide jig to improve surgical outcomes of open reduction and internal fixation with restoration and correction of orbital volume (OV) in unilateral orbital wall fractures.

METHODS

Fifteen patients with unilateral orbital fractures were assessed with ophthalmologic and radiographic parameters. The orbit was divided into three zones on computed tomography to localize defects. Fractures were coded into Fx Mx Rx Lx (F = Orbital Floor, M = Medial Wall, L = Lateral wall, R = Orbital Roof) based on pattern and specific wall involved. 1-mm sections were used to make stereolithographic models, design the custom fabricated surgical jig for intraoperative use as a guide.

RESULTS

Pre- and postoperative ophthalmological parameters, OV, were compared with the contralateral normal orbit serving as the reference. Postoperative ophthalmological parameters showed significant improvement in terms of visual acuity, enophthalmos, dystopia, and traumatic optic neuropathy. OV changes were concentrated in Zones 2 and 3. OV showed adequate restoration postoperatively.

CONCLUSION

The surgical jig served as an efficient guide to improve surgical outcomes of open reduction internal fixation. Preplanned intraoperative positioning helped achieve adequate anatomical reduction and fixation with an adequate reconstruction of OV aiding the effective transfer of virtual surgical plan on the table with improved surgical outcomes in clinical performance and functional restitution.Clinical trial registration: The Clinical Trials Registry of India (CTRI) Registration No.: CTRI/2019/11/021929.

Traumatic optic neuropathy in orbital wall fractures- diagnostic parameters and treatment outcomes: A prospective observational study

INTRODUCTION

The aim of the study was to evaluate the associated patterns of orbital wall fractures, diagnostic parameters of Traumatic optic neuropathy and its progress with Mega dose steroid therapy.

MATERIALS AND METHODS

25 patients with unilateral orbital wall fractures of traumatic aetiology were evaluated with ophthalmologic and radiographic parameters. All patients were prescribed Mega Dose Intravenous steroids irrespective of the timing of presentation. Ophthalmic assessment was repeated for same parameters every alternate day upto 2 weeks.

RESULTS

Lateral orbital wall was found to be most commonly involved. Visual acuity, Pupillary Reactivity, Visual Field and Visual Evoked Potential showed statistically significant improvement post steroid therapy in early as well as late presenters.

DISCUSSION

Highest incidence of Traumatic optic neuropathy was noted in multiple linear orbital wall fractures with highest incidence with lateral orbital wall involvement. Literature regarding Choice and timing of initiation of steroids based on timing of presentation is inadequate to justify skipping steroids to observe or undertake surgical intervention. In the present study marked improvement was noted post steroid therapy regardless of timing of presentation. The authors conclude that Visual evoked potential should be objectively tested and Mega dose steroid therapy should be initiated for all patients with Traumatic optic neuropathy for maximum benefit to the patient.

Indirect traumatic optic neuropathy

Indirect traumatic optic neuropathy (ITON) refers to optic nerve injury resulting from impact remote to the optic nerve. The mechanism of injury is not understood, and there are no confirmed protocols for prevention, mitigation or treatment. Most data concerning this condition comes from case series of civilian patients suffering blunt injury, such as from sports- or motor vehicle-related concussion, rather than military-related ballistic or blast damage. Research in this field will likely require the development of robust databases to identify patients with ITON and follow related outcomes, in addition to both in-vivo animal and virtual human models to study the mechanisms of damage and potential therapies.

[Maxillofacial fractures: midface and internal orbit : Part 1: classification and diagnosis]

Fractures of the midface and internal orbit occur isolated or in combination with other injuries. Frequently, the patients are first seen in emergency rooms responsible for the coordination of initial diagnostic procedures, followed by the transfer to specialties for further treatment. It is, therefore, important for all colleagues in traumatology to understand the basic principles of injuries to the midface. Thus, the aim of this article is the description of the anatomy and the current classification systems in use, the related clinical symptoms, and the essential diagnostic measures to obtain precise information about the injury pattern. Issues for treatment will be illustrated and discussed in "Part 2" of this article.

Role of the maxillofacial surgeon in the management of severe ocular injuries after maxillofacial fractures

Aim:

This study was designed to evaluate the incidence of severe ocular injuries associated to maxillofacial fractures and report their management in the Emergency Department.

Patients and Methods:

Among the 1779 patients admitted for maxillofacial fractures, those with partial or total loss of vision at the time of emergency consultation were included in the study. Data collected from the patients’ medical records included age, gender, mechanism of injury, location and type of facial fractures, type of ocular injuries and cause of blindness, methods of treatment, and days of hospitalization.

Results:

Forty patients (2.2%), 32 men and 8 women, ranging from 17 to 85 years of age, presented with severely reduced vision or blindness associated to fractures of the facial middle third with involvement of one or more orbital walls, mainly caused by motor vehicle and work accidents. In 18 patients, severe ocular injuries were determined by direct lesion of the globe, in 14 by direct or indirect traumatic optic neuropathy and in 8 by a retrobulbar hematoma. Direct lesion of the eyeball was treated by prompt repair or enucleation of the globe, though no or little recovery of vision was obtained. Ophthalmologic and/or maxillofacial treatment of the anterior compartment lesions of the eye allowed a partial or total recovery of the vision. A partial or total recovery of the vision was observed in almost all the patients with indirect traumatic optic neuropathy after administration of steroids according to NASCIS II protocol. Likewise, an evident improvement of the vision was obtained by immediate drainage of retrobulbar hematoma.

Conclusions:

Early diagnosis of the nature of the ophthalmic injury and treatment are important, and involvement of the ophthalmologist is mandatory.

Maxillofacial trauma--developments, innovations and controversies

Despite seat belt and alcohol legislation, craniofacial trauma still remains a common health problem and significant workload in many maxillofacial units. Although management has evolved considerably from "wiring teeth together", complex fractures can still result in cosmetic and functional deformity. Today's challenge is to consistently restore patients back to their pre-injury form and function-but this is not always possible. Greater understanding and developments have significantly improved outcomes, although controversy still exists in some areas. This review outlines some of these topics.

Acute proptosis in trauma: retrobulbar hemorrhage or orbital compartment syndrome--does it really matter?

PURPOSE

To review the nature and outcomes of acute severe proptosis in patients after craniofacial trauma, over a 6-year period.

PATIENTS AND METHODS

These were identified prospectively. The mechanism of injury, nature of the proptosis, and visual outcomes in each case were reviewed. Review of the literature was undertaken.

RESULTS

In all cases proptosis, was secondary to retrobulbar edema and not hemorrhage.

CONCLUSIONS

Many cases of "retrobulbar hemorrhage" may, in fact, be secondary to edema. This has significant implications when managing the proptosed eye on an emergent basis. Possible reasons for poor outcomes are discussed. A number of unanswered questions arise from this review.

Diagnosis and treatment of retrobulbar haematomas following blunt orbital trauma: a description of eight cases

Retrobulbar haematoma following blunt orbital trauma is a rare, but potentially serious, complication, since it can evolve rapidly from visual impairment to permanent loss of vision. This sight-threatening situation most commonly arises from orbital bleeding accompanying undisplaced fractures of the orbital walls, an event that increases the pressure inside the orbit and results in vascular damage to the optic nerve. The clinical presentation includes pain, exophthalmos with proptosis, and internal ophthalmoplegia, with impairment or loss of the pupillary reflex. A thin-layer orbital CT scan is an essential diagnostic aid. Any delay between the onset of symptoms and treatment can have a significant effect on functional recovery. Therapy is based on orbital decompression, via different surgical approaches, with the intention of reducing the pressure on the nerve and vascular structures inside the orbit. This paper presents eight cases of retrobulbar haematoma and their follow-up, in detail.

Blindness after facial fractures: A 19-year retrospective study

PURPOSE

We conducted a 19-year review of patients with facial fractures who were treated in the Iranian Maxillofacial Unit at the Mobasher Emergency Hospital, Hamedan Province, Iran, to specifically consider those fractures that resulted in blindness or severe visual impairment.

MATERIALS AND METHODS

During the period of February 16, 1984, to March 20, 2003, a total of 2,503 patients with facial fractures were operatively treated. Of these, 550 (22%) patients had orbital region fractures and were specifically studied.

RESULTS

From our facial fractures database, 83 (3.31%) patients were identified as having ocular or extraocular injuries. Of these, 39 patients (1.56%) had severe visual impairment or blindness.

CONCLUSIONS

Laterally directed forces are implied as major causative factors in blindness or visual impairment. Males (83.3%), left eye (63.3%), third and fourth age decades (53.3%), and motor vehicle accidents (63.3%) were the most commonly involved gender, site, age, and cause of monocular blindness, respectively.

Traumatic optic neuropathy: a review of 61 patients

The outcome of traumatic optic neuropathy was evaluated following penetrating and blunt injuries to assess the effect of treatment options, including high-dose steroids, surgical intervention, and observation alone. Factors that affected improvement in visual acuity were identified and quantified. Sixty-one consecutive, nonrandomized patients presenting with visual loss after facial trauma between 1984 and 1996 were assessed for outcome. Pretreatment and posttreatment visual acuities were compared using a standard ophthalmologic conversion from the values of no light perception, light perception, hand motion, finger counting, and 20/800 down to 20/15 to a logarithm of the minimum angle of resolution (log MAR). The percentage of patients showing visual improvement and the degree of improvement were calculated for each patient group and treatment method. Measurements of visual acuity are in log MAR units +/- standard error of the mean. Patients who sustained penetrating facial trauma (n = 21) had worse outcomes than patients with blunt trauma (n = 40). Improvement in visual acuity after treatment was seen in 19 percent of patients with penetrating trauma compared with 45 percent of patients with blunt trauma (p < 0.05). Furthermore, patients with penetrating trauma improved less than those with blunt trauma, with a mean improvement of 0.4 +/- 0.23 log MAR compared with 1.1 +/- 0.24 in blunt-trauma patients (p = 0.03). The patients with blunt trauma underwent further study. There was no significant difference in improvement of visual acuity in patients treated with surgical versus nonsurgical methods; however, 83 percent of patients without orbital fractures had improvement compared with 38 percent of patients with orbital fractures (p < 0.05). The mean improvement in patients without orbital fractures was 1.8 +/- 0.65 log MAR compared with 0.95 +/- 0.26 in patients with orbital fractures (p = 0.1). Twenty-seven percent of patients who had no light perception on presentation experienced improvement in visual acuity after treatment compared with 100 percent of patients who had light perception on admission (p < 0.05). The mean improvement in patients who were initially without light perception was 0.85 +/- 0.29 log MAR compared with 1.77 +/- 0.35 in patients who had light perception (p < 0.05). There were no significant differences in improvement of visual acuity when analyzing the effect of patient age and timing of surgery. Patients who sustain penetrating trauma have a worse prognosis than those with blunt trauma. The presence of no light perception and an orbital fracture are poor prognostic factors in visual loss following blunt facial trauma. It seems that clinical judgment on indication and timing of surgery, and not absolute criteria, should be used in the management of traumatic optic neuropathy.

Damage to intracranial optic pathways in fatal closed head injury in man

Head injury is a leading cause of visual impairment. This is partly due to direct trauma to the eye and optic nerve but much of the damage involves the intracranial optic pathways. We have studied the frequency, distribution and nature of the intracranial lesions of the optic pathways at autopsy in 45 cases of severe closed head injury, and examined the correlation between these post-mortem lesions and the ante-mortem clinical findings. Twenty-four of the patients had been involved in road traffic accidents. The ages ranged from 9 to 88 years (mean 46.4), the Glasgow Coma Score (GCS) on admission ranged from 3 to 15 (mean 5), and the survival time after injury from 2.5 h to15 days (mean 3.3 days). Skull fractures were present in 75.6% of the cases. Histological assessment included the use of immunohistochemistry for beta-amyloid precursor protein (beta-APP) and the microglial marker CD68. Axonal injury of varying severity was demonstrable in all cases, and in 39 (87%) the optic chiasm, tracts or radiations were involved, usually in more than one region. The severity of axonal injury was mild in 11 (24%), moderate in 9 (20%) and severe in 19 (42%) cases. The optic radiation at the level of the trigone of the lateral ventricle was particularly frequently and severely affected. The least affected parts of the intracranial optic pathways were the optic chiasm and the posterior segment of the optic nerve. The severity of injury to the optic pathways did not always reflect severity of axonal injury elsewhere in the brain and correlated poorly with the type of trauma (high- or low-velocity), presence of skull fractures or evidence of raised intracranial pressure (ICP). Of the 39 patients who survived more than 6 h, histological evidence of ischaemic injury to the primary optic cortex was present in 26 (67%) and was severe in 12. We conclude that the visual pathways are affected in a high proportion of patients with fatal closed head injury, nerve fibres in the optic radiations being particularly vulnerable. The findings suggest that damage to the posterior parts of the optic pathways may be under-diagnosed among patients with head injury.

Delayed post-traumatic visual loss: a clinical dilemma

A 16-year-old female presented with unilateral blindness in her right eye 2 months after blunt head trauma. Optic nerve edema was demonstrated by funduscopic examination, ultrasonography, and magnetic resonance imaging and failed to respond to medical treatment. Delayed post-traumatic blindness may be a severe complication of head trauma. The late appearance leads to delayed diagnosis and resulting unresponsiveness to treatment. Patients who experience head trauma that could involve the optic nerves should undergo ultrasonography of the optic nerves. An abnormal finding should be followed by an intensive evaluation to determine possible damage.

Blindness after reduction of facial fractures

Blindness in patients suffering maxillofacial trauma is usually caused by optic nerve or optic canal injuries. It is, however, an uncommon complication of facial trauma, with a reported incidence of only 2 to 5 percent. Blindness may also follow surgical repair of facial fractures. Many mechanisms, such as intraoperative direct nerve injury, retinal arteriolar occlusion associated with orbital edema, or delayed presentation of indirect optic nerve injury sustained at the time of the initial trauma, have been implicated in causing this blindness. In this article, four cases of visual loss after surgical repair of facial trauma are reported. In a review of the University of Maryland Shock Trauma experience with facial trauma over 11 years, we discovered that 2987 of the 29,474 admitted patients (10.1 percent) sustained facial fractures, and that 1338 of these fractures (44.8 percent) involved one or both of the orbits. One thousand two hundred forty of these patients underwent operative repair of their facial fractures. Three patients experienced postoperative complications that resulted in blindness, a total incidence of only 0.242 percent. Postoperative ophthalmic complications seem to be primarily mediated by indirect injury to the optic nerve and its surrounding structures. The most frequent cause of postoperative visual loss is an increase in intraorbital pressure in the optic canal. When our data were added to the summarized cases, blindness was attributable to intraorbital hemorrhage in 13 of 27 cases (48 percent). In addition, 5 cases in our review attribute the visual loss to unspecified mechanisms of increased intraorbital pressure, bringing the total cases of visual loss caused by intraorbital pressure or hemorrhage to 18 of 27 cases, or 67 percent. Within the restricted confines of the optic canal, even small changes in pressure potentially may cause ischemic optic nerve injury.