1 Principles topenlarge
A key landmark is the alignment of the greater wing of the sphenoid and of the zygoma to form the lateral orbital wall. This landmark should be visualized. This landmark is not reliable if the lateral wall of the orbit is comminuted.
Correct anatomical reduction is required to reproduce the original structure of the zygomaticomaxillary complex and the proper alignment of the orbital walls. In order to achieve proper reduction of the lateral orbital wall the greater wing of the sphenoid and the zygoma must be properly aligned.
The aim is to restore the proper orbital volume and to restore proper width, AP projection, and height of the midface. Proper reduction of the zygoma addresses the issues of AP projection of the width of the midface.
It is possible that the periorbital contents may have been affected by the reduction of the zygomatic-complex fracture. Forced duction tests should be performed before and after reduction of the zygoma to make sure that the patient does not have entrapment of the soft tissues. Pre- and postoperative ophthalmologic exams should be considered in all patients who have sustained periorbital trauma.
For the purpose of this demonstration of a 2-point exposure and fixation technique of the zygomatic complex, plates have been placed on the zygomaticofrontal suture and the fracture at the zygomaticomaxillary buttress.
2 Zygoma reduction method topenlarge
The first step is to obtain proper 3-D reduction of the zygoma using an elevator, hook, screw, or Carroll-Girard type device to mobilize the zygoma into its proper position.
Illustration shows reduction being performed via a transoral (Keen) approach placed through the maxillary vestibular incision using an elevator …
… or using a hook.
Threaded reduction tool
A threaded reduction tool (Carroll-Girard screw) is inserted into the zygoma through the lower eyelid incision or directly through the skin of the face and used for reduction.
3 Placement and fixation of first plate topenlarge
Placement of first plate
The first plate is placed across the frontozygomatic fracture area.
We recommend a minimum of a 5-hole plate with one hole spanning the fracture line. The plate should be properly adapted.
In this illustration, the first screw is placed in the unstable zygomatic fracture. An instrument is then used to pull the plate and zygomatic fragment in the cephalad direction to further reduce the fracture.
Fixation of first plate
Only one screw should be placed on each side of the fracture in the holes nearest to the fracture, until the surgeon has verified the proper 3-D reduction of the zygoma at the other two points. Looking through the upper eyelid incision, it is very difficult to determine the 3-D rotation of the zygoma.
While drilling holes in the periorbital area, it may be desirable to use a drill bit with a stop (commonly 6 mm stop).
The final two screws in the zygomaticofrontal plate should be placed at the end of the intervention.
4 Placement of additional plates topenlarge
Looking through the maxillary vestibular approach, the fracture of the
zygomaticomaxillary buttress is aligned. A larger L-shaped plate is ideal for
the fixation of this fracture. This is the most difficult plate to properly
adapt in a zygoma fracture. It is important that the leg of the L-plate be
placed on the most lateral portion of the lateral maxillary buttress, where the
bone is fairly thick.
It is similarly important that the foot of the L-plate is placed along the alveolar bone in a manner that the screws will not be placed into the dental roots. A common problem with this third plate is failure to properly adapt the L-plate, resulting in screw placement into the thin wall of the anterior maxillary sinus. It is not uncommon for the lateral maxillary buttress to be comminuted. In this instance using a longer L-plate with multiple screw holes may be ideal.
We recommend that lower profile plates are used at the frontozygomatic area. A stronger plate is recommended for the zygomaticomaxillary buttress.