Department of Plastic and Reconstructive Surgery, Yokohama City University Medical Center,

1. Distraction Osteogenesis of Nasal Bone Including Piriform Aperture Rim for SyndromicCraniosynostosis KatsuyukiTorikai, NagiNishikori, HirokiNaganishi, Mayumi Yamamoto 1, Takeshi Kijima, IkuoYonemitsu 2, Kazuo Shimazaki 2, Keiichiro Watanabe 3, Eiji Tanaka 3, Keiji Moriyama 4, Susumu Omura2 Department of Plastic and Reconstructive Surgery, Yokohama City University Medical Center, 1Department of Plastic and Reconstructive Surgery, Kawasaki Medical School, 2Department of Oral and Maxillofacial Surgery, Yokohama City University Medical Center 3Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences 4Section of Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Graduate School, Tokyo Medical and Dental University

2. Objective of the study • Syndromiccraniosynositosis has various characteristic physical findings. • We are going to report a case withsyndromiccraniosynostosis featuring severe midfacialhypoplasiawithout exophthalmos, who has mild occlusal discrepancy due to dental compensation and characteristic external nose deformity.

3. Materials and Methods: Case；A 15-year-old male Born with syndromiccraniosynostosis . At age 1；Cranioplasty for early release of the coronal suture areas with advancement of the frontal bone. At 5; Another cranioplasty for enlargement of total occipital area . At 15; Referred to our hospital for orthognathic surgery.

4. Photos of the 1st visit to our hospital 15 y.o.

5. Preoperative Cephalometric Radiogram and Profilogram SNA SNB ANB Convexty L1 to mandibular pl. Interincisal angle 64.7 70.6 - 5.9 -10.0 83.8 113.7

6. Preoperative 3D CT

7. Operation Planning；modifiedLeFort II – Le Fort I Distraction osteogenesis of nasal bone including piriform aperture rim was planned.

8. Intraoperative photos In order to get total external nose distraction, distracted bone contained antero-inferior piriform edge with nasal floor bone included.

9. Distraction Osteogenesis (DO)（RED system） DO was initiated on post operative day(POD)6 with a rate of 1mm/day until POD28. Total distraction distance was about 20 mm.

10. Postoperative Cephalometric Radiograms In order to remove RED device earlier, distracted bone was fixed by penetrating Kirschner wire (arrow) from lateral side of zygomatic bone to the other side.

11. Photos after completion of DO Kirchner wire was removed easily 5 months after completion of DO. Nasal deformity remained and we performed nasal repair twice.

12. Nasal augmentation usingcostal cartilage Nasalrepair including bilateral alar reduction 16y8m 17y 5m

13. Results Pre Op. 15 y.o. Post Op. 17 y.o.

14. Results and conclusions Our case displayed severe midfacialhypoplasia, but exophthalmos or severe occlusional discrepancy was not observed. We performed nasal and ethmoidalosteotomy with a small incision on root of nose without using coronal incision. Also, we could improve his feature by distracting nasal area forward. Furthermore, we could improve his quality of living by removing RED device earlier using Kirschner wire for consolidaton.

15. Significance of the findings It is suggested that this method, ‘ modified Le Fort II minus Le Fort I DO -including piriform aperture rim’ , might be effective in the treatment of syndromiccraniosynostosis featuring severe midfacialhypoplasia without exophthalmos, who has mild occlusal discrepancy and severe nasal deformity.