Orbital Trauma and Facial Fracture Repair
What is the Orbit?
The eye socket, or orbit, is a bony cavity that houses the eye, the muscles that move the eye, the surrounding blood vessels, nerves, and fat. Shaped like an empty ice cream cone it is composed of 7 facial bones. Each orbit can be described by the four orbital walls: the orbital roof superiorly (which lies between the orbit and the brain and frontal sinus), the medial orbital wall (which lies between the orbit and the nose, ethmoid and sphenoid sinuses), the orbital floor (which lies between the orbit and the maxillary or cheek sinus), and the lateral orbital wall (which lies between the orbit and temporal fossa). Some of the bone that makes up the medial orbital wall and the orbital floor is very thin (like an eggshell) and can be easily fractured from trauma.
What is an Orbital Floor Fracture or Blow Out Fracture?
Blunt force (like a fist) may be transmitted to the eye socket and cause an orbital fracture by two mechanisms. The object may push on the eye causing the eye to move back in the socket, increasing pressure in the orbit. This increased pressure may apply force to the thin walls and they may bend and break (fracture) or “blow out.” Alternatively, blunt force to the edge of the eye socket, the orbital rim, may cause the orbital walls to buckle and fracture.
What Problems May be Associated with an Orbital Fracture?
All patients with blunt trauma to the eye and eye socket should undergo a complete eye exam to make sure the eye was not damaged during the trauma. Sometimes the eye, muscles that move the eye, and orbital fat will become stuck, or entrapped, in the fracture. If this happens patients will develop double vision and may have severe pain and nausea. Additionally, fractures typically increase the size of the orbit and after the initial swelling resolves the eye can sink back into the orbit (enophthalmos). Most patients will discover they have an orbital fracture after they undergo a computed tomograph (CT) scan.
How are Orbital Fractures Repaired?
Depending on the size of the fracture it may need to be repaired to release entrapped orbital fat and muscle, relieve double vision, or prevent a sunken eye. Repair of orbital fractures is accomplished through small incisions on the inside of the eyelids and placement of an orbital implant (typically a very thin sheet of plastic, high-density porous polyethylene) to cover the fracture.
What is a ZMC Fracture?
The term ZMC refers to the zygomaticomaxillary complex, a large bony structure in the cheek that serves as a strut for the overlying soft tissues of the face. ZMC fractures occur from blunt trauma to the cheek or side of the face. Typically patients will develop pain with chewing and a flattening of the cheek from the fracture. These fractures also run through the lateral orbital wall and the orbital floor. These fractures may need to be repaired through incisions in the inside of the eyelid, through the mouth, and sometimes through the scalp. The displaced piece of bone is put back in place (reduced) and fixed into position with small titanium plates that hold the bone into position until it heals.