A Modified Technique of Mandibular Ramus Sagittal Split Osteotomy for Prevention of Inferior Alveolar Nerve Injury: A Prospective Cohort Study and Outcome Assessment.
BACKGROUND
Postoperative functional impairment of the inferior alveolar nerve (IAN) has been a common and well-recognized complication. Our study introduced a modified Obwegeser-Dal Pont bilateral sagittal split osteotomy (BSSO) technique and evaluated the subsequent incidence of postoperative neurosensory disturbance of IAN.


METHODS
In this prospective cohort study, 57 patients receiving our modified BSSO during orthognathic surgery were enrolled. The technique contained opening the 2 ramus cortices and inserting the osteotome bypassing the IAN to avoid nerve injury. A 5-point scale self-assessment questionnaire was used to evaluate IAN neurosensory disturbance one week, six months and 12 months postoperatively. Differences between groups were analyzed using χ test for categorical and Wilcoxon signed-rank test for pairwise categorical data.


RESULTS
Complete ramus splitting could be achieved in 109 (95.6%) sides. Lower lip or chin neurosensory disturbances presented in 72 (63.2%) sides 1 week postoperatively and gradually reduced to 9 (7.9%), and 4 (3.5%) at postoperative months 6 and 12, respectively.


CONCLUSIONS
This BSSO technique could be safely performed with low rates of IAN exposure and injury and a low incidence of persistent neurosensory disturbance in 3.5% of patients 12 months postoperatively.
From the *Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan; †Division of Plastic Surgery, Siriraj Hospital, Mahidol University, Bangkok, Thailand; ‡Craniofacial Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan; and §Seran Plastic Surgery Clinic, Incheon, Korea.
Peerasak
P
Chortrakarnkij
Daniel
D
Lonic
Hsiu-Hsia
HH
Lin
Kazuaki
K
Yamaguchi
Sun-Goo
SG
Kim
Lun-Jou
LJ
Lo
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008340:Mandibular Nerve; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods*; D010043:Outcome and Process Assessment, Health Care; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D013624:Taiwan; D061221:Trigeminal Nerve Injuries / Q000517:prevention & control*