In the last five years we have corrected nearly 750 cases of severe malocclusion by bimaxillary surgery. 76% were Angle class II patients, 5% had an open bite, 19% were Angle class III patients.

In the anamnesis the TMJ was compromised in 3,6% of the cases. Probably these patients underwent a period of juvenile osteoarthritis during puberty. Most of the cases had a class II malocclusion and an open bite. We have seen more unilateral cases than bilateral ones. More than 90% were female. On the X-rays we found an impressive posterior rotation of the mandible with increasing of the overjet. In the last five years we found reasons for this phenomenon in 13 patients before operation: professional sports, such as athletics, golf, tennis and professional playing the violin. All of them underwent gynaecological examination. There was found amenorrhoea, irregular menorrhoea, inadequate contraceptive. Hormonal treatment was done to normalise the cycle period.

The amount of jaw advancement was determined our treatment success. The more we elongated the mandible, the more condylar resorption was found.

Because of this risk factor we changed our protocol of planning surgery:

We reduced the distance of jaw movement in bimaxillary surgery. For example we reduced the maxillary advancement in class II patients. In severe cases the correction was performed in two surgical steps within one year. At first vertical ramus distraction or SARPE and after one year bimaxillary surgery. One year after surgery we have seen stable results in more than 97% of our patients.

In the post op follow up we found only one case of unilateral progressive condylar resorption. Two different corrections by distraction and secondary BSSO were performed. We reached an improved but not a sufficient result.