[Analysis of three dimensional stability of the hypoplastic maxilla after orthognathic surgery in cleft lip and palate patients].
OBJECTIVE
To establish a three dimensional spacial measurement method to analyze the short-term stability of maxilla after orthognathic surgery in cleft lip and palate patients.


METHODS
Twenty-five patients with maxillary hypoplasia secondary to cleft lip and palate seeking for orthognathic surgery were included in this study between January 2008 and September 2012. The spiral CT scan for the skull were taken 6 weeks preoperatively (T0), 4 days postoperatively (T1)，3 months postoperatively (T2), and 6 months postoperatively (T3) and collected. A three dimensional analytic method for measuring maxilla was set up in ProPlan CMF software, and good repeatability of identification of landmarks was confirmed. Twenty-two indicators to describe the maxillary position and three new angles to describe the maxillary orientation were measured and analyzed. Student's t test was used to analyze the difference between T2 and T3 using SPSS 16.0 software package.


RESULTS
In 25 patients with cleft palate there was a translational relapse upwards along vertical axis and a pitch-up relapse of maxilla with an average of 7.46% at the anterior part of the cleft maxilla. The relapse rate was 30.95% in LUCLP, 8.01% in RUCLP, and 34.76% in BCLP, but with no significant difference. Along the horizontal axis, there was a maxillary translational relapse toward noncleft side in both LUCLP and RUCLP group, while a yaw relapse was confirmed with the anterior part of maxilla toward noncleft side and the posterior part toward cleft side.


CONCLUSIONS
There is a three-dimensional relapse tendency for the maxilla in the cleft patient postoperatively. The established three-dimensional analytic method well describes the special position of cleft maxilla especially in the translational and rotational movement of maxilla in three different axes comparing with that from lateral cephalometry, thus providing references for accurate measurements in study of the three dimensional maxillary stability after orthognathic surgery.
Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine; Shanghai Key Laboratory of Stomatology. Shanghai 200011, China. E-mail:ywjz0312@163.com.
Jun-Zi
JZ
Yingwang
Shun-Yao
SY
Shen
Biao
B
Li
Hao
H
Sun
Xu-Dong
XD
Wang
D002508:Cephalometry; D002971:Cleft Lip / Q000601:surgery*; D002972:Cleft Palate / Q000601:surgery*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008437:Maxilla / Q000473:pathology*; D008844:Micrognathism / Q000175:diagnosis*; D057909:Orthognathic Surgery; D019340:Osteotomy, Le Fort; D012008:Recurrence; D012886:Skull; D036542:Tomography, Spiral Computed