What Are the Contributing Factors for Postsurgical Relapse After Two-Jaw Surgery in Patients With Cleft Lip and Palate.

The purpose of this study was to investigate the amount and pattern of postsurgical relapse after 2-jaw surgery in cleft lip and palate patients in terms of the sagittal and vertical aspects. The samples consisted of 21 adult patients who had the similar initial skeletodental pattern before surgery and underwent 2-jaw surgery. They were divided into high relapse (n = 11) and low relapse groups (n = 10) (criteria, 30% forward relapse of the B point). After the cephalometric variables of cephalograms taken at 1 month before surgery (T0), immediately after surgery (T1), and at least 1 year after surgery (T2) were measured, the Wilcoxon test, Mann-Whitney U test, and Pearson correlation test were performed for statistical analysis. When compared with the low relapse group, the high relapse group exhibited significant counterclockwise rotation of the distal segment of the mandible resulting in more forward movement of the mandible and significant labioversion of the maxillary incisors during T1-T2. The amount of postsurgical relapse of the mandible had a positive relationship with the amounts of setback and clockwise rotation of the mandible with surgery. In addition, the more decrease in overbite through surgery occurred, the more relapse (forward movement of the mandible) produced. Therefore, for the prevention of significant postsurgical relapse of the mandible in cleft patients, it is necessary to reduce unnecessary clockwise rotation of the mandible and to increase the vertical stability of maxilla during orthognathic surgery.