title: Single stage surgery for contouring the prominent mandibular angle with a broad chin deformity: en-bloc Mandibular Angle-Body-Chin Curved Ostectomy (MABCCO) and Outer Cortex Grinding (OCG).
abstract: BACKGROUND
  Various surgical options are reported to address the Asian 'squared face', characterized by a prominent mandibular angle (PMA) associated with an oversized chin deformity; but shortcomings lie in the requirement of multi-stage procedures with the risk of further revision surgery. We have developed a single-stage "Mandibular Angle-Body-Chin Curved Ostectomy (MABCCO) and Outer Cortex Grinding (OCG)" surgical technique to shorten the period of the surgical treatment and minimize the inherent surgical risks in the multi-staged procedures.
  
  
  METHODS
  A retrospective study involving patients (n = 36) presented with prominent mandibular angle and an oversized chin who underwent the operation described from 2010 to 2012 with at least 12 months of follow-up. The surgical and aesthetic outcomes were evaluated through clinical assessment, photography, imaging analysis including preoperative and post-operative patient satisfaction rates.
  
  
  RESULTS
  All the patients were satisfied with the improvement in their appearance following surgery; specifically the 'smoothness' of the mandibular inferior border with no 'second mandibular angle'. The width of the mandible was reduced with G-G distance reduced from 119.9 mm ± 3.9-109.7 mm ± 3.5 (p < 0.05). A significant preoperative and post-operative gonial angle (G-A) was found at the left (110.7° ± 9.6 vs 139.9° ± 11.5, p < 0.05) and right side of mandible (111.3° ± 10.7 vs 140.7° ± 11.8, p < 0.05). There was no iatrogenic inferior alveolar nerve or mental nerve injury and a stable aesthetic outcome beyond the first year.
  
  
  CONCLUSIONS
  We demonstrated favourable surgical and aesthetic outcomes with our single-stage en-bloc curved osteotomy surgical technique to reshape the prominent mandibular angle with a broad chin deformity with no increased in surgical risks but a high satisfaction rate and stable outcomes.
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Teng
authors.affiliation: Department of Plastic and Reconstructive Surgery, Temple Street Children University Hospital, Temple Street, Dublin 1, Ireland.
authors.forename: Fuan Chiang
authors.initials: FC
authors.lastname: Chan
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Jia-Jie
authors.initials: JJ
authors.lastname: Xu
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Jian-Jian
authors.initials: JJ
authors.lastname: Lu
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Xie
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Jing-Yi
authors.initials: JY
authors.lastname: Zhao
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China.
authors.forename: Mei-Bang
authors.initials: MB
authors.lastname: Xu
authors.affiliation: Craniomaxillofacial Surgery Department 2, Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 33 Ba-Da-Chu Road, Shi Jing Shan District, Beijing 100144, PR China. Electronic address: zhengxingwuke2@163.com.
authors.forename: Xiao-Lei
authors.initials: XL
authors.lastname: Jin
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods; D002680:Chin / Q000002:abnormalities* / Q000473:pathology; D017076:Computer-Aided Design; D004954:Esthetics; D005260:Female; D005500:Follow-Up Studies; D063172:Genioplasty / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008334:Mandible / Q000002:abnormalities* / Q000473:pathology; D063168:Mandibular Osteotomy / Q000379:methods*; D010347:Patient Care Planning; D017060:Patient Satisfaction; D010781:Photography / Q000379:methods; D011183:Postoperative Complications; D012189:Retrospective Studies; D016896:Treatment Outcome; D014584:User-Computer Interface; D055815:Young Adult
keywords: Body of mandible; Long curved ostectomy; Mandibular angle ostectomy; Second mandibular angle; broad chin