Blow out fracture is one of the common injuries of orbit. This is commonly caused due to frontal blunt injury to orbit causing fracture of the floor of the orbit. Orbital fat / extraocular muscles may be entrapped within the fracture fragments. Commonly entrapped extraocular muscle is inferior oblique muscle. Usually entrapment of these muscles causes diplopia when the patient attempts to look down. Blow out fracture also creates enophtholmos since prolapse of orbital contents into the maxillary sinus through the fractured floor causes reduction in the volume of orbital contents.
Clinical features of blow out fracture orbit:
1. Orbital swelling immediately
3. Step deformity of infraorbital rim and crepitus on palpation
4. Entrapment of infraorbital nerve will cause anesthesia over the chin on that side
5. Positive forced duction test - in patients with entrapment of inferior oblique muscle
6. Diplopia on looking down
Should ideally be performed after reduction of orbital oedema.
Caldwell Luc procedure should be performed. Through the opening in the anterior wall of maxillary sinus the fractured floor of orbit is elevated. The fractured fragments can be held in position by placing plate and screws via a subciliary incision. Two incisions are necessary for successful reduction of blow out fracture conventionally. The first one is the sublabial incision to perform caldwell luc procedure, and the second one is the subciliary incision to stabilize the fractured fragments.
Endoscopic reduction of blow out fracture:
Advent of endoscopes have helped in the management of blow out fracture under vision.
Step 1: A caldwell luc procedure is first performed by creating an opening in the anterior wall of maxilla. An endoscope is introduced through the opening and the fracture is reduced under vision
Step 2: Inferior meatal antrostomy is performed using Miles retrograde gouge.
Step 3: Foley's catheter is introduced into the maxillary antrum through the inferior meatal antrostomy and its bulb is inflated with air. The inflated bulb holds the reduced fractured fragments in position and it should be retained for atleast 6 weeks.