Traumatic avulsion of the globe with optic nerve transection: an unusual presentation

Abstract

Complete globe extrusion, whether traumatic or spontaneous, is a rare clinical entity and if associated with optic nerve avulsion, it has a worse visual outcome, though repositioning of the globe may be attempted. We report a case of road traffic accident, wherein the patient presented with an extrusion of the globe, along with a complete transection of the optic nerve, about 4 cm from the optic nerve head, with only a residual attachment to the orbital rim via the unsevered lateral conjunctival flap, where the enucleation was completed and the conjunctiva was sutured.

Background

Complete extrusion of the globe with or without an associated optic nerve avulsion is a rare presentation that may occur spontaneously or results from severe facial or orbital trauma.¹ Globe avulsions are classified as incomplete, in which only the optic nerve is severed, and complete, wherein there is a disruption of the extraocular muscles and optic nerve resulting in a total luxation of the ocular bulb.² There is a wide range of causes that may lead to a globe and optic nerve avulsion, but a severe maxillofacial trauma associated with globe extrusion should always raise a suspicion of an optic nerve avulsion. Although the spectrum of ocular injuries is vast, an optic nerve transection following a complete globe protrusion is very rare. Herein, we present a case with complete globe avulsion and optic nerve transection following a road traffic accident.

Case presentation

A 41-year-old man presented to the casualty unit of All India Institute of Medical Sciences (AIIMS), Jodhpur, with a history of a road traffic accident, he met while driving a two-wheeled vehicle. Following the road traffic accident, the patient was taken to a nearby hospital where the facial lacerations, that he had sustained were repaired and he was referred to AIIMS, Jodhpur, on the same day. The patient complained of severe pain and complete loss of vision in the left eye immediately after the accident. The patient was conscious and his general condition was stable with a Glasgow Coma Scale score of 15, physical examination revealed an oedematous and bruised face with a nasal pack in situ. The patient was examined by the specialists from departments of ophthalmology, otorhinolaryngology, neurosurgery and oro-maxillofacial surgery. On bedside ophthalmic examination, he could count fingers up to 3 m with his right eye and inspection of the adnexa revealed a wedge-shaped, full-thickness laceration involving the lateral half of upper eyelid associated with oedema and conjunctival chemosis. The anterior and posterior segment was within normal limits. However, the left globe along with the optic nerve, 4 cm length from the optic nerve head was luxated outside the orbital socket leaving only the conjunctiva and lateral rectus muscle attached to the lateral orbital rim and supporting the globe, rest all the muscle attachments of the globe were lost. No direct or consensual pupillary light reflexes or eye movements could be elicited in the left eye (figure 1).

Figure 1.

(A) Clinical photograph of the patient at presentation to the casualty unit, showing sutured facial lacerations and an avulsed left globe. (B) Clinical photograph of the patient, showing an avulsed left globe with completely transected optic nerve stump measuring approximately 4 cm.

Investigations

A non-contrast CT of head and orbit was ordered which was suggestive of subarachnoid haemorrhage with complex Le-Fort’s maxillofacial fracture with involvement of the medial wall and floor of right orbit with fracture line extending through the maxillary midline. Also, fracture of the floor, medial and lateral wall of the left orbit and that of nasal septum associated with extrusion of the left globe from the orbital socket and a transected optic nerve were noted. Avulsion of all extraocular muscles from the globe was seen except that of the lateral rectus muscle (figure 2).

Figure 2.

Non-contrast CT of head and orbit axial view depicting an extrusion of left globe with an attached transected optic nerve stump. Globe is attached to the orbital rim temporally via the lateral rectus muscle. Avulsed medial rectus muscle and multiple fractures of medial wall of orbit and nasal septum can be appreciated.

Treatment

A team consisting of an oro-maxillofacial surgeon, an otorhinolaryngologist, a neurosurgeon and an ophthalmologist examined the patient and formulated the management plan. After an initial evaluation in the emergency unit and ensuring a stable systemic profile a written informed consent was taken and, the patient was shifted to operation room, where enucleation of the protruding left globe was completed under general anaesthesia and the repair of the right upper eyelid laceration was performed along with the transpalatal wiring by an oromaxillofacial surgeon. Postoperatively once the patient was stabilised, the visual acuity of the right eye was evaluated using Snellen chart which was recorded to be 6/6 parts and signs suggesting corneal desiccation due to exposure were noted. This eye was also screened for any retinal pathology after dilatation of pupil, which revealed no anomaly. A course of systemic antibiotics and steroids was administered and steroids were tapered until the facial and orbital oedema resolved along with topical antibiotics and carboxymethyl cellulose drops in both eyes. After the facial oedema subsided in 5 days, facial fractures were repaired with wires.

Outcome and follow-up

The patient has reported symptomatic relief from the complaints of congestion and pain. The conjunctival sutures of left eye are now absorbed with no signs of any residual infection or any signs suggesting a contraction of the socket at present and the orbital volume measured on follow-up at 1 month was 25 cc (figure 3). The laceration on the right upper eyelid healed appropriately. The sutures were removed on seventh day and the final vision on follow-up is 6/6. On follow-up at 1 month, the patient had a complaint of persistent epiphora in the left eye. Syringing and probing were performed and a hard stop was palpable at 12 mm likely to be due to involvement of the nasal bones. The patient was re-evaluated after 4 weeks by an otorhinolaryngologist and is now planned to undergo a nasolacrimal duct stent insertion following reconstruction of the nasal septum.

Figure 3.

Clinical photograph of the patient at 2 weeks post-surgery, showing sutured facial and right upper eyelid laceration and left post-enucleated socket.

Discussion

The optic nerve and the globes are generally resistant to mild-to-moderate magnitude of trauma.² However, globe avulsion may result from trauma as trivial as a finger prick injury, or severe facial and orbital fractures following a road traffic accidents³ or rarely after an animal attack or physical assault.⁴

Maxillofacial injuries and single or multiple orbital fractures are often associated with an extraocular muscle injury, therefore optic nerve avulsion should be suspected in all cases of maxillofacial trauma associated with globe protrusion.⁵ Neurological complications such as orbital infection, meningitis, intracranial or subarachnoid haemorrhage and cerebrospinal fluid leakage are some of the life- threatening complications that may occur following globe avulsion.⁶ Therefore, a neurological examination is essential. Brain and orbital CT scans are imperative to exclude intracranial bleeding, optic chiasmal injury and bone fractures.

Morris et al described several different mechanisms leading to the event of globe luxation:⁷

1. A wedge-shaped or an elongated object invades the medial orbit using the nasal sidewall as a fulcrum, and propelling the globe forward;

2. Sudden marked elevation of intra-orbital pressure due to orbital volume reduction by multiple orbital and facial fractures, leading to the displacement of the globe from its socket;

3. Deceleration force leading to extreme rotation and forward displacement of the globe causing shearing of the optic nerve fibres.

This happens most commonly at the lamina cribrosa, as the loss of myelin and absence of supportive connective tissue septa make the axons highly susceptible to damage at this location.

In our case, the mechanism of injury was a combination of sudden deceleration and multiple facial and orbital fractures reducing the orbital volume, resulting in globe luxation anteriorly.

A spontaneous globe subluxation following trauma has rarely been reported in the literature. There exists one such case report of bilateral globe subluxation with complete optic nerve transection resulting from accident.^{1 2} However, a case like ours, with traumatic auto-enucleation an attached optic nerve stalk has never been reported.

The primary goal of management in such cases is the prevention of visual impairment. If the optic nerve is partially avulsed, partial recovery of visual function is possible.⁸ However, in completely transected optic nerves with the absence of visual function, only cosmetic concerns may become important and its management is controversial. There exist two schools of thought, some authors recommend primary enucleation because of nil visual prognosis,⁷ others suggest repositioning of the globe, presuming that saving the eye reduces the psychological trauma of losing an organ, secondarily we can easily fit an ocular prosthesis with better motility on the phthisical eye.⁹ Although, even globe repositioning is associated with a high risk of the bulbar atrophy due to ischaemia.³ Some of the reported cases of the avulsed globe were replaced into the orbit without later requirement of enucleation, while others needed subsequent enucleation due to pain, prolonged ocular inflammation and an unsatisfying cosmetic result but no signs of sympathetic ophthalmia were noted in these cases.¹⁰ Therefore, keeping in mind that there is no defined treatment protocol for optic nerve avulsion,¹¹ variable visual outcomes can be expected, depending on the visual acuity at the presentation after the injury,¹² thus, it is necessary to have a management plan tailored for each case to optimise the visual prognosis.

In our case enucleating the dislocated globe was considered unavoidable since the patient had an associated complete optic nerve transection with disrupted blood supply and disinsertion of multiple extraocular muscles. The ocular findings mentioned above and the presence of severe maxillofacial trauma and subarachnoid haemorrhage necessitated a comprehensive multidisciplinary approach.

Eye trauma constitutes 7% of all bodily injuries and 10% to 15% of all eye diseases.¹³

Optic nerve avulsion with complete globe protrusion is a very rare presentation of maxillofacial trauma. Optic nerve avulsion causes nerve damage leading to permanent visual acuity impairment. Therefore, the best approach for these patients is organised management for globe preservation for few months aiming for the best outcome, which can help to establish a better psychological impact and cosmetic rehabilitation before further prosthetic eye procedures are attempted.

Learning points.

• We report a case of severe facial trauma following a road traffic accident that presented as a complete globe extrusion with optic nerve transection, a comprehensive multidisciplinary approach is essential to minimise patient’s disability.

• The outcome depends on the visual acuity following the injury. However, optic nerve avulsion causes permanent visual acuity impairment. Therefore, the best approach in such a scenario is devising tailored management for maximising globe salvage wherever possible.

• Repositioning the globe and reattaching the extraocular muscles instead of enucleation can help improve the ocular prosthesis fitting and globe motility and also has a better psychological and cosmetic acceptability.

• Severe maxillofacial trauma and orbital fractures are often associated with an occult extraocular muscle injury and impinging of the optic nerve with fractured bone fragments, therefore an assessment of the pupillary reflexes and optic nerve function should always be carried out in such cases.