title: Three-dimensional assessment of zygomatic malunion using computed tomography in patients with cheek ptosis caused by reduction malarplasty.
abstract: BACKGROUND
  Reduction malarplasty is one of the most popular aesthetic surgical procedures for reshaping facial contour in oriental people. Especially for those who have a wide midface and a prominent zygoma. Although malunion and cheek ptosis are known as major complications in reduction malarplasty, but there have been few reports about their causes and patterns. The authors experienced many revision reduction malarplasty using the coronal approach to correct cheek ptosis with malunion and were able to categorize the types of malunion by analyzing 3-dimensional CT imaging prior to revision surgery.
  
  
  METHODS
  A total of 24 patients underwent revision reduction malarplasty with the coronal approach to correct the unfavorable result after primary malarplasty. Most patients complained of various degrees of cheek ptosis associated with malunion. In all cases, the status of zygomatic malunion was evaluated through 3D CT imaging. The operative procedures during revision surgery including repositioning of the inferolaterally displaced malar complex to the appropriate position and obtaining bone-to-bone contact with rigid fixation. If bony absorption at non-union margin was found during the operation, bihalved calvarial bone was grafted into the bony gap. Midface and forehead lifts were also performed when indicated.
  
  
  RESULTS
  The types of zygomatic malunion could be categorized into four patterns according to the shape of displacement. The degree of displacement was relevant to the condition of the fixation in all cases. The higher the grade of malunion was evaluated in 3D CT imaging, the more difficult procedures it required during revision surgery. The postoperative results in all cases were satisfactory without any complications.
  
  
  CONCLUSIONS
  In reduction malarplasty, inappropriate fixation and the ignorance of repositioning vector can lead to cheek ptosis and malunion by the action of masseter muscle. The malunion types apprehended by the preoperative 3D CT scanning enabled precise operative planning before revision surgery. In all grades of zygomatic malunion with cheek ptosis, revision reduction malarplasty with coronal approach was a very useful solution because it offers a wide surgical field, enables accurate repositioning along with firm fixation and easily allows simultaneous midface lift.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Sungnam-si, Gyeonggi-do 463-707, Republic of Korea.
authors.forename: Rong-Min
authors.initials: RM
authors.lastname: Baek
authors.forename: Jino
authors.initials: J
authors.lastname: Kim
authors.forename: Baek-Kyu
authors.initials: BK
authors.lastname: Kim
mesh_terms: D000328:Adult; D044466:Asian People; D002610:Cheek; D004954:Esthetics; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D011183:Postoperative Complications; D019651:Plastic Surgery Procedures / Q000379:methods*; D012086:Reoperation; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D015050:Zygoma / Q000000981:diagnostic imaging / Q000601:surgery*