title: C1 lateral mass screw insertion with protection of C1-C2 venous sinus: technical note and review of the literature.
abstract: METHODS
  This is a technical note and review of the literature.
  
  
  OBJECTIVE
  We propose to describe a revised surgical technique of C1 lateral mass screw insertion with protection of C1-C2 venous sinus surrounding the C2 nerve root.
  
  
  BACKGROUND
  During C1 lateral mass screw insertion and in posterior C1-C2 fixation, iatrogenic injury of C1-C2 venous sinus results in bleeding, which is troublesome. Appropriate management of the venous sinus in this region is critical to successful surgery in this complex anatomic region.
  
  
  METHODS
  We reviewed 48 patients who underwent posterior C1-C2 fixation at our institution between September 2001 and October 2008. Twenty-four atlas screws were inserted by the originally described C1 lateral mass screw technique (group A), and 28 through a revised posterior arch and lateral mass screw technique (C1 transpedicular screw) (group B). The final group of 44 atlas screws was placed with our newly revised technique (group C).
  
  
  RESULTS
  Bleeding of venous sinus was encountered in 3 group A, 2 group B, and 1 group C atlas screw insertions. The incidence rate was 12.50% (A), 7.14% (B), and 2.27% (C). Statistical comparison showed no significant difference between the groups. All the cases were followed for a mean period of 28.1 month. Four patients in group A complained of postoperative numbness in occipitocervical region. No patients in group B or group C voiced this complaint. A high fusion rate was found in all 3 groups with no signs of implant failure.
  
  
  CONCLUSIONS
  Bleeding of C1-C2 venous sinus is vigorous and frustrating. The revised technique we describe provides theoretical and practical protection of venous sinus. In addition, the firm bony purchase of screws afforded by this technique contributes to achieving stabilization of the upper cervical spine and a high fusion rate.
authors.affiliation: Department of Orthopedics and Traumatology, Shanghai East Hospital, Tongji University, Shanghai, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Pan
authors.forename: Lijun
authors.initials: L
authors.lastname: Li
authors.forename: Lie
authors.initials: L
authors.lastname: Qian
authors.forename: Jun
authors.initials: J
authors.lastname: Tan
authors.forename: Guixin
authors.initials: G
authors.lastname: Sun
authors.forename: Xin
authors.initials: X
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000098:blood supply* / Q000473:pathology / Q000601:surgery*; D001863:Bone Screws / Q000592:standards*; D001270:Cervical Atlas / Q000098:blood supply* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*; D014680:Veins / Q000033:anatomy & histology / Q000601:surgery