Traumatic optic neuropathy: facial CT findings affecting visual acuity

Effects of light perception on visual function recovery in patients with traumatic optic neuropathy

This study aimed to assess the impact of light perception presence or absence on visual function recovery in patients with traumatic optic neuropathy (TON). A retrospective analysis was conducted on the clinical data of 206 TON patients. Based on the presence or absence of light perception after injury, patients were categorized into a light perception group and a non-light perception group. A comparison was made between the two groups regarding visual acuity recovery before and after treatment. The non-light perception group comprised 63 patients, with a treatment effectiveness rate of 39.68%. The light perception group consisted of 143 patients, with a treatment effectiveness rate of 74.83%. The difference between the two groups was statistically significant (χ2 = 23.464, P < 0.01). Subgroup analysis indicated that surgical treatment appeared to be more effective than steroid hormone therapy for patients with light perception. Conversely, for patients without light perception, there was no significant difference in the effectiveness of the two methods. The total effectiveness rate of the light perception group was significantly higher than that of the non-light perception group, suggesting that patients with light perception before treatment experience better outcomes compared to those without light perception. Treatment choices should be individualized to ensure optimal results.

Trauma to the Eye: Diffusion Restriction on MRI as a Surrogate Marker for Blindness

Traumatic optic nerve injury may lead to almost instantaneous blindness. We describe a case of sight loss after a perforating injury to the eye. The case is unusual in that the patient remained conscious and the trauma to the eye was isolated. A full ophthalmological examination was therefore possible within hours as well as early magnetic resonance imaging of the facial skull. High-quality T1-weighted, T2-weighted, and diffusion-weighted imaging could be acquired. The latter included apparent diffusion coefficient maps. There was a loss of the subarachnoid space of the optic nerve, fluid in the retrobulbar fat of the affected eye, and signal changes in the optic nerve. Previous work has been contradictory on the signal of the optic nerve on apparent diffusion coefficient maps in sight loss, with an increase seen by one group and a decrease seen by another. Signal loss on the apparent diffusion coefficient map was seen in the case described here. Signal loss on apparent diffusion coefficient maps may thus be used as a surrogate marker of sight loss in patients who are unconscious or otherwise unable to cooperate in ophthalmological exams.

Evaluation of the neuroprotective effects of methylprednisolone and surgical decompression in a rodent model of traumatic optic neuropathy

PURPOSE OF THE STUDY

Traumatic optic neuropathy (TON) is a rare but serious consequence of head injuries. The optimal therapy for TON remains controversial, and standardized recommendations are lacking. The most common therapies used are steroid administration and surgical decompression procedures. The aim of the present study was to compare two common conservative and surgical therapies in a rodent model with a standardized traumatic optic nerve lesion.

MATERIALS AND METHODS

This study employed 59 male Wistar rats. After exposing the optic nerve, defined trauma was exerted on the optic nerve using a micromanipulator to trigger TON. Rats received either "megadose" methylprednisolone applied perioperatively or decompression via nerve sheath fenestration. The number of neurons was histologically evaluated in retinae explanted as whole mounts. Neuronal size was determined histomorphometrically.

RESULTS

Neuronal loss was significantly lower following perioperative "megadose" steroid therapy (p = 0.017), especially in the central retinal area (p = 0.025). Compared to the control group without therapy, on average more than 400 neurons/mm² were saved. In the central retinal area, more than 600 neurons/mm² were rescued. In contrast, neuronal loss was not significantly affected by surgical decompression; however, this procedure was associated with a reduction in neuron size (p = 0.003).

CONCLUSIONS

The present model revealed significant neuroprotective effects following administration of methylprednisolone for TON treatment. Mitigation of neuronal loss may result in functional benefits. Neuroprotective effects were not observed following surgical therapy, suggesting that this approach should be reserved for individual cases such as hematomas in the area of nerve envelopes.

Surgical Treatment and Visual Outcomes of Adult Orbital Roof Fractures

BACKGROUND

Fractures of the orbital roof require high-energy trauma and have been linked to high rates of neurologic and ocular complications. However, there is a paucity of literature exploring the association between injury, management, and visual prognosis.

METHODS

The authors performed a 3-year retrospective review of orbital roof fracture admissions to a Level I trauma center. Fracture displacement, comminution, and frontobasal type were ascertained from computed tomographic images. Pretreatment characteristics of operative orbital roof fractures were compared to those of nonoperative fractures. Risk factors for ophthalmologic complications were assessed using univariable/multivariable regression analyses.

RESULTS

In total, 225 patients fulfilled the inclusion criteria. Fractures were most commonly nondisplaced [n = 118 (52.4 percent)] and/or of type II frontobasal pattern (linear vault involving) [n = 100 (48.5 percent)]. Eight patients underwent open reduction and internal fixation of their orbital roof fractures (14.0 percent of displaced fractures). All repairs took place within 10 days from injury. Traumatic optic neuropathy [n = 19 (12.3 percent)] and retrobulbar hematoma [n = 11 (7.1 percent)] were the most common ophthalmologic complications, and led to long-term visual impairment in 51.6 percent of cases.

CONCLUSIONS

Most orbital roof fractures can be managed conservatively, with no patients in this cohort incurring long-term fracture-related complications or returning for secondary treatment. Early fracture treatment is safe and may be beneficial in patients with vertical dysmotility, globe malposition, and/or a defect surface area larger than 4 cm2. Ophthalmologic prognosis is generally favorable; however, traumatic optic neuropathy is major cause of worse visual outcome in this population.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

A Systematic Literature Review on Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is an uncommon vision-threatening disorder that can be caused by ocular or head trauma and is categorized into direct and indirect TON. The overall incidence of TON is 0.7-2.5%, and indirect TON has a higher prevalence than direct TON. Detection of an afferent pupillary defect in the presence of an intact globe in a patient with ocular or head trauma with decreased visual acuity strongly suggests TON. However, afferent pupillary defects may be difficult to detect in patients who have received narcotics that cause pupillary constriction and in those with bilateral TON. Mechanical shearing of the optic nerve axons and contusion necrosis due to immediate ischemia from damage to the optic nerve microcirculation and apoptosis of neurons is a probable mechanism. The proper management of TON is controversial. High-dose corticosteroid therapy and decompression of the optic nerve provide no additional benefit over observation alone. Intravenous erythropoietin may be a safe and efficient treatment for patients with TON.

Role of delayed wider endoscopic optic decompression for traumatic optic neuropathy: a single-center surgical experience

BACKGROUND

The aim of the present study was to discuss the efficacy of delayed wider endoscopic optic decompression in traumatic optic neuropathy (TON).

METHODS

A total of 479 patients were treated with corticosteroids and delayed wider endoscopic optic decompression, including the injury-to-surgery interval, within 2 weeks in patients with no light perception (NLP), and within 1 month in patients with residual eyesight. Based on the traditional decompression range, the superior wall of the optic canal was further decompressed. The preoperative and postoperative visual acuities (VAs) were reviewed, and the therapeutic efficacy was analyzed.

RESULTS

The final VA was 0.1 or better in 29 cases, finger count in 79 cases, hand motion in 99 cases, light perception (LP) in 25 cases, and NLP in 247 cases. A total of 136 patients (136/383, 35.5%) recovered after NLP treatment, and 78 patients (69/96, 71.9%) had improved residual eyesight. The improvement rate in patients with residual eyesight was significantly higher than that of patients with NLP (P<0.01). Moreover, the total VA after treatment was better than that before surgery (P<0.01).

CONCLUSIONS

Delayed wider optic nerve decompression plus corticosteroids remains an effective and safe therapeutic strategy for patients with delayed treatment intervals of more than 1 week, especially for those with residual eyesight within 1 month.

CT Features of Posttraumatic Vision Loss

Clinical evaluation of patients with trauma is challenging, especially in the presence of neurologic injuries. Vision loss after trauma is a harmful and usually overlooked consequence that may be avoided with a prompt and accurate intervention. Head CT is commonly performed in patients with trauma. However, radiologists may be unfamiliar with the CT findings associated with injuries that may affect eyesight. Understanding the visual pathway anatomy and its critical landmarks is paramount for recognizing these findings. This article describes the use of head CT to evaluate the visual pathway to help avoid vision loss in patients with trauma. Injuries are presented in terms of those affecting the globe (rupture, hemorrhage, and lens trauma), optic nerve (direct and indirect traumatic optic neuropathy), orbit (orbital compression syndrome), and vasculature (traumatic carotid-cavernous sinus fistula and posterior cerebral artery injury or ischemia). Techniques for measuring the globe on CT to assess for injury are illustrated. Indications for screening CTA of the head and neck in patients with suspicion for blunt traumatic vascular injury are summarized. Emphasis is placed on the CT findings that warrant an emergency intervention to prevent traumatic visual impairment.

Diagnostic imaging in neuro-ophthalmology

Neuro-ophthalmology is a field combining neurology and ophthalmology that studies diseases that affect the visual system and the mechanisms that control eye movement and pupil function. Imaging tests make it possible to thoroughly assess the relevant anatomy and disease of the structures that make up the visual pathway, the nerves that control eye and pupil movement, and the orbital structures themselves. This article is divided into three sections (review of the anatomy, appropriate imaging techniques, and evaluation of disease according to clinical symptoms), with the aim of providing useful tools that will enable radiologists to choose the best imaging technique for the differential diagnosis of patients' problems to reach the correct diagnosis of their disease.

Prognostic Predictors of Visual Outcome in Open Globe Injury: Emphasis on Facial CT Findings

BACKGROUND AND PURPOSE

The present prognostic models for open globe injuries have a limited ability to predict visual outcome before a comprehensive ophthalmologic examination or operation because they depend on the data derived from the ophthalmologic examination and intraoperative findings. The purpose of our study was to determine the specific CT and preoperative clinical data that can predict the prognosis of open globe injury.

MATERIALS AND METHODS

We analyzed the relationship of 29 variables derived from clinical and CT data from 97 globe injuries with visual acuity at 1 month. A prediction model was derived from 49 globe injuries by regression analysis, followed by receiver operating characteristic curve analysis of the best CT predictor.

RESULTS

Four variables with significance on a regression model were the following: posterior segment hemorrhage (β = -0.93, P < .0001), presenting visual acuity (β = 0.28, P = .042), orbital emphysema (β = 0.46, P = .0018), and complex facial fracture (β = -0.43, P = .009). Receiver operating characteristic analysis of the posterior segment hemorrhage predicted profound vision loss (light perception or no light perception) with an area under the curve of 0.97. The receiver operating characteristic table indicated that grade III posterior segment hemorrhage has a strong positive predictive value of 100% for profound vision loss. On the other hand, the absence of posterior segment hemorrhage has a strong positive predictive value of 93% for mild-to-severe vision loss (visual acuity better than light perception).

CONCLUSIONS

Radiologists, with the help of CT and preoperative clinical data, can predict visual acuity after open globe injury.

Direct traumatic optic neuropathy in a temporal laceration: A case report

Facial lacerations are a common presentation in emergency departments. It is important to appreciate the mechanism of injury and the anatomy of structures involved in penetrating lacerations in the maxillofacial region. A 65-year-old man suffered an accidental penetrating injury with a sharp kitchen knife to the right temporal region. There was a single laceration to the right temporal region. The right eye had no perception to light, a total afferent and efferent pupillary defect and partial ophthalmoplegia. Computerised tomography scan revealed signs of penetration through the skin, temporalis, postero-lateral orbital wall and orbital apex. There was no injury to the globe or either retrobulbar or intracranial haemorrhage. A diagnosis of direct traumatic optic neuropathy was made following consultation with opthalmology and neurosurgery teams. Only two similar cases of penetrating trauma in the temporal region resulting in direct traumatic optic neuropathy have been identified in the literature. This case presentation highlights the structures that are at risk of damage from penetrating trauma in the maxillofacial region.

Treatment Outcomes following Traumatic Optic Neuropathy

BACKGROUND

Traumatic optic neuropathy is characterized by sudden loss of vision following facial trauma leading to variable visual deficits. The purpose of this study was to evaluate recent institutional trends in the treatment of traumatic optic neuropathy, evaluate the outcomes of different treatment strategies, and identify factors associated with improved vision.

METHODS

Institutional review board approval was obtained to retrospectively review patients diagnosed with traumatic optic neuropathy at a high-volume trauma center from 2004 to 2012. Pretreatment and posttreatment visual acuity was compared using quantitative analysis of standard ophthalmologic conversion.

RESULTS

A total of 109 patients met inclusion criteria (74.3 percent male patients), with a mean age of 38.0 ± 17.5 years (range, 8 to 82 years). Management of traumatic optic neuropathy involved intravenous corticosteroids alone in 8.3 percent of patients (n = 9), 56.9 percent (n = 62) underwent observation, 28.4 percent (n = 31) had surgical intervention, and 6.4 percent (n = 7) underwent surgery and corticosteroid administration. Only 19.3 percent of patients returned for follow-up. Vision improved in 47.6 percent of patients, with a mean follow-up of 12.9 weeks. Patients younger than 50 years had a trend toward higher rates of visual improvement, 60 percent versus 16.7 percent (p = 0.15).

CONCLUSIONS

The majority of traumatic optic neuropathy patients are unlikely to return for a follow-up examination. Optic nerve decompression has fallen out of favor in the authors' institution, and observation is the most common management strategy. Outcomes following corticosteroid administration and observation are comparable.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Usefulness of Extradural Optic Nerve Decompression via Trans-Superior Orbital Fissure Approach for Treatment of Traumatic Optic Nerve Injury: Surgical Procedures and Techniques from Experience with 8 Consecutive Patients

OBJECTIVE

To describe our experience of extradural optic nerve decompression via the trans-superior orbital fissure approach for traumatic optic neuropathy (TON) and retrospectively analyze its advantages and pitfalls.

METHODS

Between September 2009 and August 2014, 8 consecutive patients with TON underwent extradural optic canal decompression via the trans-superior orbital fissure approach. We retrospectively reviewed medical charts, radiologic findings, surgical techniques, complications, and final surgical results.

RESULTS

All 8 patients presented with visual disturbance caused by head injury; 2 patients had no light perception, 6 had light perception, and 2 had ophthalmoplegia. All patients underwent extradural optic canal decompression and high-dose steroid administration within 24 hours after injury. Postoperative visual acuity on discharge was improved in 6 patients and unchanged in 2. The 2 patients with ophthalmoplegia gradually recovered by 3 months after operation. The postoperative outcome was good recovery in 7 patients and moderate disability in 1 patient. There were no complications related to the surgical procedure.

CONCLUSIONS

Emergent optic canal release has been recommended in patients with TON. The advantage of the extradural optic canal decompression via the trans-superior orbital fissure approach is easy identification of the optic canal after partial removal of the anterior clinoid process, resulting in fewer surgical complications. In addition, this procedure can achieve intraorbital decompression if necessary. We recommend this modified approach with mini-peeling as a safe and reliable procedure in patients with TON.

Significance of post-traumatic maxillary sinus fluid, or lack of fluid, in a level II trauma population

Our goal was to test the predictive value of high-attenuation material within the maxillary sinus for adjacent facial bone fracture. After IRB approval, all blunt trauma facial CTs performed over a 5-month period at a level II trauma center were reviewed in consensus by three radiologists for the presence of facial fractures or high attenuation maxillary sinus opacity (≥30HU, ≥40HU, or ≥50HU). Three classes of fractures were analyzed: any fracture, any fracture contiguous with the maxillary sinus, and only fractures not contiguous with the maxillary sinus. Statistics were calculated using two-by-two tables. A total of 844 cases were reviewed with 273 patients having any fracture. There were 402 hemi-faces with any fracture and 62 hemi-faces with fracture contiguous with the maxillary sinus. Sensitivity, specificity, positive predictive value, and negative predictive value for any fracture (using the ≥40HU threshold) were 13, 99, 85, and 78 % respectively; for fracture contiguous with the sinus, these were 71, 99, 72, and 99 % respectively; and for only non-contiguous fractures, these were 2.3, 96, 13, and 80 %, respectively. We conclude that in this level II trauma population, lack of high attenuation maxillary sinus material nearly ruled out fractures in contiguity with the sinus. High-attenuation sinus material is only moderately predictive of a fracture contiguous with the maxillary sinus. Therefore, if after careful review a fracture is not identified, the radiologist should not be overly concerned that a fracture is being missed. High-attenuation sinus material is a poor marker for fractures not contiguous with the maxillary sinus.