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C1-C2 Posterior Fixation: Are 4 Screws Better Than 2?

Vergara, Pierluigi MD; Bal, Jarnail Singh MBChB; Hickman Casey, Adrian Thomas FRCS; Crockard, Hugh Alan FRCS; Choi, David FRCS

doi: 10.1227/NEU.0b013e318243180a
Technique Assessment

BACKGROUND: Several types of C1-C2 fixation techniques have been described over the years in order to treat atlantoaxial instability.

OBJECTIVE: To compare the pros and cons of the most popular C1-C2 posterior fixation used today: C1 lateral mass-C2 pedicle screw and rods (Harms) and transarticular screw (Magerl) fixations.

METHODS: Retrospective review of 122 patients who underwent Harms or Magerl fixation for atlantoaxial instability. Surgical, clinical, and radiological outcomes were compared in the 2 groups.

RESULTS: 123 operations were performed, of which 47 were by the Harms technique (group H) and 76 by the Magerl technique (group M). No significant differences were found in duration of surgery, blood loss, postoperative pain, and length of hospitalization. Postoperatively, neck pain, C2-radiculopathy, and hand function improved in both groups, with better, but not statistically significant, results for group H. The intraoperative complication rate was 2.1% in group H and 21% in group M (P < .05); postoperative complication rate was 10.6% in group H and 21% in group M (P > .05). The major complications were vertebral artery injury (2.1% in group H, 13.1% in group M, P = .05) and screw fracture (2.1% in group H, 9.2% in group M, P > .05). Fusion rate at the end of follow-up was not significantly higher in group H. C1-C2 range of movements in flexion/extension at the end of follow-up was lower in group H (P = .017).

CONCLUSION: Magerl with posterior wiring and Harms techniques are both effective options for stabilizing the atlantoaxial complex. However, the Harms technique appears to be safer, to have fewer complications, and to demonstrate a more robust long-term fixation.

ABBREVIATIONS: ADI, anterior atlantodental interval

PADI, posterior atlantodental interval

TIA, transient ischemic attack

Department of Neurosurgery, The National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom

Correspondence: Pierluigi Vergara, MD, Via Napoli 35, 80011-Acerra (NA), Italy. E-mail:

Received February 24, 2011

Accepted November 1, 2011

Copyright © by the Congress of Neurological Surgeons