Globe avulsion due to impact by motor cycle gear shift

Eye globe avulsion is a result of extreme trauma. Although the spectrum of eye globe injuries is wide, however total avulsion of the eye globe is rare [1]. Eye globe avulsions are classified as incomplete and complete [2], [3]. In complete eye globe avulsion there is a disruption of the extraocular muscles and optic nerve resuting in total luxation of the ocular bulb, whereas incomplete avulsion only the optic nerve is damaged severely [2], [3]. We report a case of traumatic avulsion associated with motor vehicle accident.

A 19-year-old male presented to the emergency room. The patient met with a motor cycle accident seven days prior to admission. He was using a helmet without a face cover. He was found with the gear shift of the motorcycle which is present in the foot area, embeded below the eye into the socket and he had to be pulled away from it. At the emergency room, he was conscious with a GCS of 15/15. On physical examination the left eye was positioned outside the eyelid fissure, hanging by an array of tissues that seemed to be superior and inferior oblique muscles as well as orbital fat (Figure 1). The inferior palpebra was lacerated full thickness and hanging by the temporal canthus (Figure 2).

Clinically, the patient also had a blowout fracture and hematosinus in the left maxilary sinus (Figure 3). CT scan images also showed protrusion of the left globe suggestive of avulsion of the optic nerve (Figure 3). Intracranial structures were normal as well as the right eye that had 20/20 vision and no sign of trauma. The patient was hospitalized and intravenous antibiotic and corticosteroid were continued.

The patient underwent surgery. Exploration was done under general anestesia and then enucleation was done due to the improbability of repositioning the eyeball and no possibility of recovering visual function. Before the procedure, further examination was done to evaluate the extent of the trauma. It was found that the rectus muscle was released entirely from the globe except for the superior and inferior oblique muscles. The optic nerve was avulsed at 20 mm posterior to the globe (Figure 4). There was a full thickness wound horizontally in the posterior portion of the globe lateral to the optic nerve which causes the globe to become hypotonous.

Both of the superior and inferior lid was lacerated full thickness. The superior lid was lacerated 10 mm form the lateral canthus. The inferior lid was lacerated full thickness starting at 5 mm from the nasal cantus to the temporal side with a width of 25 mm making the inferior lid avulsed and hanging from the temporal canthus. Both of the superior lid and inferior lid was sutured back to its anatomical position starting at the grey line. The conjunctival part of the palpebra was then sutured, followed by the orbicularis oculi muscles and ending it with a subcuticular suture of the skin for better esthetics. The final follow up showed excellent cosmetic result after prosthetic fitting (Figure 5).

Fifty-five million eye trauma cases happen every year around the world. In Indonesia, eye trauma is the 6th most common trauma [4]. Eye trauma is classified by Birmingam eye trauma terminology (BETTS) and overall classified as open and closed eye globe injury [5]. In this case, the patient has an open eye globe injury due to a high impact collision to a foot gear shift, causing a rupture in the ocular wall, laceration of the lower lid, blow out fracture and avulsion of the eye globe. Avulsion of the eye globe has its own classification; complete avulsion in which there is disruption of the extraocular muscles and optic nerve resuting in total luxation of the ocular bulb, whereas in incomplete avulsion only the optic nerve is damaged severely [2], [3]. Eye globe avulsion can be a rare finding and it is usually caused by severe trauma to the head, face and orbit [4]. The mechanism of trauma that may cause eye globe avulsion are (a) elongated object enters the medial orbit, causing the globe to propel forward, (b) a wedge shape object enters the eye globe forward, displaing the eye globe anteriorly, (c) a sharp object penetrate and directly transect the optic nerve [6]. Several cases have been reported with various mechanism of trauma such as motor vehice accident, bear attack, domestic violence, sport injuries, or trauma due to selfgauging with a finger by patient with drug abuse [2], [7], [8].

The patient was riding a motorcyle when he collided with another motorcycle from the opposite direction. The patient was propelled forward and landed with his face towards the foot gear shift of the opposing motorcycle. He was wearing a helmet, however it was without face cover. This is probably the reason behind the salvaging other structures of the face including bone and soft tissues surrounding the avulsed globe. The foot gear shift has a blunt edge to it, however with a high force, it can serve as a wedge that displace the eye globe anteriorly causing globe avulsion as well as rigged edges laceration at the lower and upper lid and blow out fracture.

With high impact, a blunt object enteres the orbit with high force and damages the ocular muscles. The rupture may happen due to direct impact anterior to the anulus of Zinn, hence all four rectus muscles were damaged. The superior oblique muscle was untouched due to its superior position in anatomy compared to the rectus muscles. Additional damage may also have occured when the patient was pulled away from the foot gear shift. The inferior oblique muscle was unharmed due to the entrance of the object that was lower than its anatomical position.

The fracture occur in the maxillary bone (inferior wall of the orbit) and combined with the bleeding in the orbital area, the blood entered the maxillary sinus making the appearance of hematosinus in the CT scan. The orbit is the bony cavity that contains the globe, extraocular muscles, nerves, fat and blood vessels [9]. This cavity consist of four walls; the roof, the floor, the lateral and medial wall, the weakest point being the lamina papyracea located in the posteromedial portion of the maxillary bone [9].

Globe avulsion is one of the complication of head trauma and is a rare ocular trauma presentation. In Indonesia, safety measures on the road is not taken seriously and laws regarding traffic safety and regulations are not enforced to the fullest extent. Low education and minimal safety promotion increase the possibilty of ocular injuries. With this case report we hope to bring awareness to motorcycle users to always be safe and use protective helmets with adequate protection to the face to prevent such injuries.