[Evaluation of minimally invasive therapy of zygomatic bone fractures with a classification proposal]

The pre- and postoperative symptoms of zygomatic bone fractures were examined in a follow-up study to prepare a classification proposal. A differential indication for minimally invasive therapy modes was looked for with respect to this proposal. Therapy of isolated zygomatic bone fractures consisted in repositioning with a hook and miniplate fixation across the frontozygomatic suture. The aims of this study were clinical and radiological assessment of the repositioning result in terms of aesthetics and stability and quantification of the postoperative remission of disturbances of sensitivity of the infraorbital nerve. A total of 52 patients were examined. After the operation (on average after 3.5 days following the trauma) they were followed-up postoperatively for 12 months according to a strict schedule. Preoperatively, 49 patients reported disturbances of sensitivity of the infraorbital nerve. Other symptoms, such as periorbital haematoma and flattening of the zygomatic prominence, were observed in 49 patients and 45 patients, respectively. All fractures were repositioned well as assessed clinically and radiologically. The aesthetic result was evaluated as symmetric and durable in all cases. Six months postoperatively 41 patients reported normal sensitivity in the area of the infraorbital nerve. In only five patients (10.2%) was the sensitivity loss persistent throughout the entire follow-up period. Patients with primarily lacking diplopia developed neither eye motility disturbances nor postoperative enophthalmus in the following period. It can be concluded that the treatment of an isolated zygomatic bone fracture which satisfies aesthetic and functional requirements is possible by reposition and fixation with one miniplate at the lateral orbital rim. An additional osteosynthesis at the infraorbital rim or at the zygomaticomaxillary crista is not necessary. A routine revision of the orbital floor is only indicated in cases of preoperative diplopia. A zygomatic bone fracture connected with diplopia should be classified as combined zygomatic-/orbital floor fracture.