[Influencing factors of sensory disturbance of lower lip after sagittal split ramus osteotomy].
OBJECTIVE
This study was designed to evaluate the influencing factors of sensory disturbance of lower lip after sagittal split ramus osteotomy(SSRO).


METHODS
We studied 19 consecutive patients that underwent a total of 37 SSROs from September 2004 to September 2005. The follow-up period was 24 weeks. The condition of sensory disturbance was measured using touch test, prick test and two-point discrimination test. The standard of the BMRC grading system was used to evaluate sensory function. SAS6.12 software package was used for Chi-square test.


RESULTS
No significant differences of sensory disturbance was found between male and female(P>0.05). The recovery rates of sensory disturbance of lower lip had significant differences between patients who had intraoperative nerve exposure and patients who didn't have(P<0.05). If distal segment's movement was more than 6mm, the recovery rates of sensory disturbance of lower lip decreased from 100% to 68.2%, the difference was statistically significant (P<0.05).


CONCLUSIONS
Intraoperative nerve exposure and greater amount of distal segment's setback will certainly increase the degree of sensory disturbance of the lower lip. It is suggested that the extent of movement is less than 6mm.
Department of Oral and Maxillofacial Surgery, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China. maxillofacsurg@163.com
Hao
H
Yuan
Guo-fang
GF
Shen
Xu-dong
XD
Wang
D002680:Chin; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008046:Lip / Q000294:innervation / Q000503:physiopathology*; D008297:Male; D008334:Mandible; D059229:Osteotomy, Sagittal Split Ramus; D014110:Touch