Asian Spine J.  2012 Sep;6(3):168-177. 10.4184/asj.2012.6.3.168.

Computer-assisted C1-C2 Transarticular Screw Fixation "Magerl Technique" for Atlantoaxial Instability

• Uehara M
• Takahashi
• Hirabayashi H
• Hashidate
• Ogihara N
• Mukaiyama
• Kato H

• KMID: 2270456
• DOI: http://doi.org/10.4184/asj.2012.6.3.168

Abstract

STUDY DESIGN: A retrospective study. PURPOSE: To evaluate the surgical results of computer-assisted C1-C2 transarticular screw fixation for atlantoaxial instability and the usefulness of the navigation system. OVERVIEW OF LITERATURE: We used a computed tomography (CT)-based computer navigation system in planning and screw insertion in Magerl's procedure, which provides the most rigid atlantoaxial fusion, to avoid risk of vertebral artery (VA) tear by avoiding high-riding VA during screw insertion.
METHODS
Twenty patients who underwent atlantoaxial fusion under the CT-based navigation system were studied. The mean observation period was 33.5 months. The evaluated items included the existence of VA stenosis by preoperative magnetic resonance angiography, surgical time, blood loss volume, Japanese Orthopaedic Association (JOA) score and Ranawat's pain criteria before surgery and at final follow-up, postoperative screw position evaluated by CT, and bony fusion.
RESULTS
The mean operation time was 205 minutes, with the mean blood loss volume of 242 ml. The mean JOA score was 11.6 points before surgery and 13.7 at final follow-up. Occipital and/or cervical pain presented before operation was remitted or resolved in all patients. Evaluation of screw insertion by CT revealed correct penetration to atlantoaxial joints, with a perforation rate of 2.6%. There was no complication, including VA tear, and all patients who were followed-up during one year or more after surgery achieved bony fusion. Some subjects who appeared inappropriate for surgery from CT images were assessed as eligible for surgery based on the evaluation results obtained using the navigation system.
CONCLUSIONS
It was demonstrated that the CT-based navigation system is an effective support device for Magerl's procedure.

Keyword

Atlantoaxial joint; Atlantoaxial instability; CT-based computer navigation system; C1-C2 transarticular screw fixation

MeSH Terms

Asian Continental Ancestry Group
Atlanto-Axial Joint
Congenital Abnormalities
Constriction, Pathologic
Follow-Up Studies
Humans
Magnetic Resonance Angiography
Neck Pain
Operative Time
Retrospective Studies
Vertebral Artery
Atlanto-Axial Joint
Congenital Abnormalities