Clinical PapersA Modified Technique of Mandibular Ramus Sagittal Split Osteotomy for Prevention of Inferior Alveolar Nerve Injury A Prospective Cohort Study and Outcome AssessmentChortrakarnkij, Peerasak MD; Lonic, Daniel MD; Lin, Hsiu-Hsia PhD; Yamaguchi, Kazuaki MD; Kim, Sun-Goo MD; Lo, Lun-Jou MDAuthor Information 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. Received October 19, 2016, and accepted for publication, after revision December 16, 2016. This study was presented at the 10th Asian Pacific Craniofacial Association Conference in Adelaide, October 3–5, 2014. This trial is registered with clinicaltrials.gov, number NCT02634840. This study was performed in the Imaging Lab, Chang Gung Craniofacial Research Center, and supported by a grant from Chang Gung Memorial Hospital, CRRPG5C0271-3 and CRRPG5C0281-3. Conflicts of interest and sources of funding: none declared. Reprints: Lun-Jou Lo, MD, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital. 5 Fu-Shin Street, Kwei Shan, Taoyuan, Taiwan 333. E-mail: [email protected]. P.C., D.L., S.K., and L.J.L. conceived and designed the experiments. P.C. and D.L. performed the experiments. D.L., P.C., H.H.L., and K.Y. analyzed the data. D.L. and P.C. wrote the article. L.J.L. did the final editing and project supervision. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.annalsplasticsurgery.com). Annals of Plastic Surgery: March 2017 - Volume 78 - Issue 3 - p S108-S116 doi: 10.1097/SAP.0000000000001015 Buy SDC Metrics Abstract 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 χ2 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. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.