title: Feasibility of intralaminar, lateral mass, or pedicle axis vertebra screws in children under 10 years of age:  a tomographic study.
abstract: BACKGROUND
  There are several techniques for screw insertion in upper cervical spine surgery, and the use of the 3.5-mm screw is usually the standard. However, there is no consensus regarding the feasibility of using these screws in the pediatric population.
  
  
  OBJECTIVE
  To determine the measurement of the lamina angle, lamina and pedicle length and thickness, and lateral mass length of the topographic axial view of the axis vertebra of 2- to 10-year-old children to guide the use of surgical screws.
  
  
  METHODS
  Seventy-five computed tomography scans from 24- to 120-month-old patients were studied. Measurements were taken in an axial view of C2 and correlated with 2 age groups and both sexes. Statistical analysis was performed with the Student t test.
  
  
  RESULTS
  In the 24- to 48-month age group, only 5.5% of the lamina and 8.3% of the pedicles had thicknesses < 3.5 mm. In the 49- to 120-month age group, there were no lamina thickness values < 3.5 mm, and 1.2% of pedicle thicknesses were < 3.5 mm. Both age groups had no lamina and pedicle lengths < 12 mm and no lateral mass lengths > 12 mm.
  
  
  CONCLUSIONS
  In the majority of cases, the use of 3.5-mm lamina and pedicle screws in children is feasible. A base value of 45° for the spinolaminar angle can be adopted as a reference for insertion of screws in the C2 lamina. This information can be particularly useful for decision making during preoperative planning for C1-C2 or craniocervical arthrodesis in children.
authors.affiliation: Spine Division, Orthopaedics and Traumatology Institute, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. aacristante@uol.com.br
authors.forename: Alexandre Fogaça
authors.initials: AF
authors.lastname: Cristante
authors.forename: Alessandro Gonzalez
authors.initials: AG
authors.lastname: Torelli
authors.forename: Rafael Bellucci
authors.initials: RB
authors.lastname: Kohlmann
authors.forename: Ivan
authors.initials: I
authors.lastname: Dias da Rocha
authors.forename: Olavo Letaif
authors.initials: OL
authors.lastname: Biraghi
authors.forename: Alexandre Sadao
authors.initials: AS
authors.lastname: Iutaka
authors.forename: Raphael Martus
authors.initials: RM
authors.lastname: Marcon
authors.forename: Reginaldo Perilo
authors.initials: RP
authors.lastname: Oliveira
authors.forename: Tarcísio Eloy
authors.initials: TE
authors.lastname: Pessoa de Barros Filho
mesh_terms: D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging* / Q000601:surgery*; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed