title: Placement of C-7 intralaminar screws: a quantitative anatomical and morphometric evaluation.
abstract: OBJECTIVE
  Crossing laminar screws at C-7 have been recently described as a method for the fixation of C-7. In this study the authors measured locations on axial CT scans to determine the feasibility of placing a screw in the C-7 lamina, and they evaluated the reliability of the surface of the dorsal arch of C-7 as a landmark for determining the optimal site of screw entry.
  
  
  METHODS
  A total of 207 axial CT scans of C-7 spines were evaluated, and 4 critical measurements were determined for screw entry points, trajectories, and lengths for placement of intralaminar screws.
  
  
  RESULTS
  The mean width of the right C-7 lamina was 5.9 mm (range 4.2-9.3 mm). The mean width of the left C-7 lamina was 6.0 mm (range 4.2-10.2 mm). The laminar width was too small (< 5.5 mm) in 37.7% of cases to accommodate a 3.5-mm diameter screw, given the desire for at least 1 mm of play on each side of the screw.
  
  
  CONCLUSIONS
  These measurements provide guidelines for operating on the posterior aspect of C-7 and enhance the confidence of the surgeon. Viewing the anatomy of the C-7 laminae in detail through preoperative CT scanning can greatly assist the surgeon in choosing the fixation method. The width of the C-7 lamina is sufficient for intralaminar screw placement in more than 60% of patients.
authors.affiliation: Departments of Neurosurgery, Kahramanmaraş Sütçüimam Universitesi School of Medicine, Kahramanmaraş, Turkey. mehmetsenoglu@hotmail.com
authors.forename: Mehmet
authors.initials: M
authors.lastname: Şenoğlu
authors.forename: Fuat
authors.initials: F
authors.lastname: Özkan
authors.forename: Mustafa
authors.initials: M
authors.lastname: Çelik
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed; D055815:Young Adult