title: Occipital-C2 transarticular fixation for occipitocervical instability associated with occipitalization of the atlas in patients with klippel-feil syndrome, using intraoperative 3-dimensional navigation system.
abstract: METHODS
  Retrospective case series.
  
  
  OBJECTIVE
  The aim of this study was to describe the clinical outcomes of cervical reduction and occipital-C2 transarticular (OCTA) fixation with an assistance of intraoperative 3-dimensional navigation system (ITNS) during the treatment of reducible occipitocervical instability (OCI) in patients with Klippel-Feil syndrome (KFS) with occipitalization of the atlas and fusion of C2-C3.
  
  
  BACKGROUND
  Patients with KFS have congenital fusions of at least 2 cervical segments and may gradually develop symptoms at the hypermobile articulations adjacent to the cervical synostosis. This is particularly common in patients with KFS with occipitalization of the atlas and C2-C3 fusion. These patients may be at risk for instability and neurological complications of the occipitocervical junction that require occipitocervical reconstruction and fusion. Numerous treatment techniques are available for this pathological condition. However, there has yet to be a study of reducible OCI, showing successful treatment with intraoperative reduction and posterior OCTA fixation using ITNS.
  
  
  METHODS
  From 2006 to 2011, 9 patients with KFS with reducible OCI attributed to occipitalization of the atlas and C2-C3 fusion were surgically treated. After a limited foramen magnum decompression, reduction of the OCI was conducted by intraoperative cervical traction and extension, followed by OCTA fixation using a direct posterior approach and with the assistance of ITNS. The follow-up period ranged from 6 to 60 months (mean, 31 mo).
  
  
  RESULTS
  Good decompression and bone fusion were achieved in all the patients. The clinical symptoms had improved for all patients. There were no intraoperative or postoperative complications.
  
  
  CONCLUSIONS
  In patients with KFS with occipitalization of the atlas and C2-C3 fusion, manual cervical traction in tandem with cervical extension, followed by posterior OCTA fixation and fusion provides a safe, effective treatment of OCI and ventral brainstem impingement. IFTN is a feasible tool for monitoring cervical reduction and OCTA screw insertion in patients with KFS with this pathological condition.
authors.affiliation: Department of Spine Surgery, Peking University Fourth Clinical Medical College, Beijing Jishuitan Hospital, Beijing, China. orthdanielcw@yahoo.com
authors.forename: Wei
authors.initials: W
authors.lastname: Tian
authors.forename: Chong
authors.initials: C
authors.lastname: Weng
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.forename: Yu-Qing
authors.initials: YQ
authors.lastname: Sun
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yuan
authors.forename: Yong-Gang
authors.initials: YG
authors.lastname: Xing
authors.forename: Da
authors.initials: D
authors.lastname: He
mesh_terms: D000328:Adult; D001268:Atlanto-Axial Joint / Q000601:surgery; D001270:Cervical Atlas / Q000601:surgery; D002574:Cervical Vertebrae / Q000002:abnormalities / Q000601:surgery*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D005539:Foramen Magnum / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007593:Joint Instability / Q000150:complications / Q000601:surgery*; D007714:Klippel-Feil Syndrome / Q000150:complications*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D009777:Occipital Bone / Q000601:surgery*; D012189:Retrospective Studies; D016896:Treatment Outcome