title: Freehand C1 lateral mass screw fixation technique: our experience.
abstract: BACKGROUND
  Although C1 lateral mass fixation technique is frequently performed in upper cervical instabilities, it requires the guidance of fluoroscopic imaging. The fluoroscopy guidance is time-consuming and has the risks of accumulative radiation. Biplane fluoroscopy is also difficult in upper cervical pathologic conditions because of the use of cranial fixations. This study aimed to demonstrate that unicortical C1 lateral mass screws could be placed safely and rapidly without fluoroscopy guidance.
  
  
  METHODS
  Between 2002 and 2008, 32 C1 lateral mass screws were inserted in 17 consecutive patients with various pathologic conditions involving either atlantoaxial or occipitocervical instability.
  
  
  RESULTS
  C1 screw lengths ranged from 18 to 32 mm. The atlantoaxial fixation was performed in 13 patients, and C1 lateral mass screws were added to the occipitocervical construct in 3 patients, to the posterior cervical construct in 2 patients, and to the cervicothoracic construct in 1 patient. In 2 patients, because C1 lateral mass screws could not be inserted unilaterally, C1 pedicle screw analogs were inserted. There were no screw malpositions or neurovascular complications related to screw insertion. Operation time and intraoperative bleeding of the isolated atlantoaxial fixations were retrospectively evaluated. The mean follow-up was 32.3 months (range, 7-59 months). No screw loosening or construct failure was observed within this period. Postoperatively, 4 patients complained of hypoesthesia, whereas one patient had superficial wound infection.
  
  
  CONCLUSIONS
  C1 lateral mass screws may be used safely and rapidly in upper cervical instabilities without intraoperative fluoroscopy guidance and the use of the spinal navigation systems. Preoperative planning and determining the ideal screw insertion point, the ideal trajections, and the lengths of the screws are the most important points.
authors.affiliation: Neurosurgery Department, Ministry of Health, Diskapi Educational and Research Hospital, Ankara 06110, Turkey.
authors.forename: Serkan
authors.initials: S
authors.lastname: Simsek
authors.forename: Kazim
authors.initials: K
authors.lastname: Yigitkanli
authors.forename: Hakan
authors.initials: H
authors.lastname: Seckin
authors.forename: Cetin
authors.initials: C
authors.lastname: Akyol
authors.forename: Deniz
authors.initials: D
authors.lastname: Belen
authors.forename: Murad
authors.initials: M
authors.lastname: Bavbek
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000473:pathology / Q000601:surgery*; D001269:Atlanto-Occipital Joint / Q000473:pathology / Q000601:surgery*; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D002648:Child; D005260:Female; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis; D013122:Spinal Diseases / Q000175:diagnosis / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D014057:Tomography, X-Ray Computed; D055815:Young Adult