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Case of the week 136  ( October 2013 )
Fracture of the Medial Orbital Wall


This 25 years old young man has had a sever car accident in Saudia Arabia 2 years ago. 2 major operations had been done by fasciomaxillary  surgeons to repair the face and maxilla, now he asks for a treatment to the diplopia and esotropia he suffered since the accident. Apart from the motility disorders, no other ocular abnormalities could be discovered during examination.



 See video of this patient
 


 When an eye fails to fully execute a duction, especially post traumatic,  the question arises whether this limitation of ocular motility is caused by a paresis or paralysis, a mechanical restriction, or a combination of the two.

Provided the patient is cooperative, forced ductions are performed in the office after anesthetizing the conjunctiva with several drops of proparacaine hydrochloride, tetracaine, or 4% lidocaine. The conjunctiva is then grasped with a forceps close to the limbus, and the examiner tries to complete the limited duction while the patient looks into the direction of the apparently underacting muscle. Care has to be taken not to press the eye into the orbit during this test because this may simulate free forced ductions when, in fact, restrictions are present. If passive ductions are free, a paresis or paralysis is assumed to be present. If the ductions are restricted, a mechanical obstacle to ocular motility is present. 

The generated muscle force is estimated.  Saccadic velocity is observed or measured and recorded when the necessary equipment is available.

In patients with restricted forced ductions, generated muscle force may be positive within a limited scope of eye movement. In this case, the intraocular pressure increases when the eye attempts to look in the field of limited movement . This is an indirect measure of generated force. In addition, in this limited area of movement, the saccade may be brisk rather than floating. When intraocular pressure increases in the presence of a limited duction or if a brisk saccade is seen in the limited duction, restriction of motility with intact innervation can be inferred. In such cases, release of the restriction may suffice in realigning the eyes.

If there is no generated muscle force in the presence of restriction, surgical removal of the restriction in addition to muscle transposition procedures may be indicated to restore ocular alignment in primary position.

In evaluating a patient with a possible medial wall fracture of the orbit, certain key points need to be elicited on history, especially since early symptoms may be minimal. Any events associated with the actual trauma, such as loss of vision or loss of consciousness, nose blowing, diplopia, epistaxis and cerebrospinal fluid rhinorrhea should be elicited.

Although data indicate that isolated medial wall fractures are not frequent, concomitant medial wall and floor fractures are more frequent. Common causes for this type of medial wall fracture include fists, elbows, shoe kicks, and tennis balls, all of which have a diameter greater than the orbital rim.  

Clinical findings suggestive of a medial wall fracture include periorbital edema and ecchymosis, subconjunctival hemorrhage, subcutaneous emphysema, epistaxis, CSF rhinorrhea, narrowing of the palpebral fissure, restriction of abduction, limitation of adduction, the acquired retraction syndrome or retraction of the globe on attempted abduction or adduction, horizontal diplopia, and progressive enophthalmos. Medial wall fractures also tend to be commonly associated with nasal fractures. The most striking features of an isolated medial wall fracture are diplopia on medial and lateral gaze and/or enophthalmos.

Medial orbital fractures with true incarceration of the medial rectus muscle are rare. However, diagnosis of a medial wall fracture is often suggested by medial rectus entrapment. Patients with restriction of the medial rectus muscle and its surrounding connective tissue may present with horizontal diplopia, pain on abduction, restriction of abduction and adduction, and positive forced duction test.

A pseudo–Duane retraction syndrome or retraction of the globe and narrowing of the palpebral fissure upon attempted abduction may occur with medial wall fracture associated with medial rectus entrapment, and it is pathognomonic for this complication.

Fractures of the medial orbital wall may cause little, if any, symptomatology. Operative treatment is not necessary if a displaced medial wall fracture shows no clinical diplopia, minimal enophthalmos, and no signs of herniation of orbital contents into the ethmoid sinus. A good functional and cosmetic result can be expected in this situation.

Early enophthalmos of 2 mm or more, which may be cosmetically unacceptable to the patient, is also an indication for repair of the medial wall fracture. However, it should be noted that if an isolated medial wall fracture causes enophthalmos only, it may be advisable to wait until the fracture has healed and then put material on the floor to repair the enophthalmos.

 The goals of surgical treatment for medial wall fractures are restoration of good ocular motility, including single binocular vision in all fields of gaze, and improvement of significant enophthalmos. The primary goal is the complete reduction of the entrapped medial rectus muscle along with any other herniated orbital soft tissues. This may be followed by covering of the bony defect with an implant to prevent prolapse of tissue with possible reincarceration of tissue or late enophthalmos.




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