title: [Treatment of fixed atlantoaxial dislocation and basilar invagination with C1-2 screw and rod reduction and fixation technique].
abstract: OBJECTIVE
  To introduce a novel technique of reducing fixed atlantoaxial dislocation (FAAD) and basilar invagination (BI) with C1-C2 screw and rod system.
  
  
  METHODS
  From January 2009 to December 2011, 26 patients of FAAD and BI were reduced successfully with an insertion of C1 lateral mass and C2 pedicle/pars screw and rod system. The cohort had 17 females and 9 males. And their most common presenting symptoms were extremity muscle weakness, restricted neck movement and paresthesia.
  
  
  RESULTS
  All of them achieved effective reduction. Among them, 18 attained complete reduction and 8 partial reduction (over 60% extent of reduction). The mean atlanto-dental interval (ADI) value was 2.1 mm postoperatively versus 8.8 mm preoperatively (t = 21.1, P < 0.01) . All of them had relieved compression of dura and medulla oblongata and cervical cord. All clinical symptoms improved. One case had pulmonary infection while another case delayed healing of incision. Both recovered well after symptomatic treatments. Bony fusion reached 100% during a mean follow-up period of 22 months.
  
  
  CONCLUSIONS
  The C1-C2 screw and rod system may achieve effective reduction and fixation for FAAD and BI. Capable of preserving atlanto-occipital joints in patients without atlas assimilation, this procedure provide more solid immobilization than occipitocervical fusion in those with atlas assimilation.
authors.affiliation: Department of Neurosurgery, PLA General Hospital, Beijing 100853 China.
authors.forename: Yiheng
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Department of Neurosurgery, PLA General Hospital, Beijing 100853 China.
authors.forename: Xinguang
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, PLA General Hospital, Beijing 100853 China. Email: qgy301@126.com.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Qiao
authors.affiliation: Department of Neurosurgery, PLA General Hospital, Beijing 100853 China.
authors.forename: Huaiyu
authors.initials: H
authors.lastname: Tong
authors.affiliation: Department of Neurosurgery, PLA General Hospital, Beijing 100853 China.
authors.forename: Dingbiao
authors.initials: D
authors.lastname: Zhou
mesh_terms: D001268:Atlanto-Axial Joint; D001863:Bone Screws; D002574:Cervical Vertebrae; D005260:Female; D006801:Humans; D004204:Joint Dislocations; D008297:Male; D065289:Pedicle Screws; D011184:Postoperative Period; D019651:Plastic Surgery Procedures; D013123:Spinal Fusion