Targeting a Safe Entry Point for C2 Pedicle Screw Fixation in Patients with Atlantoaxial Instability.
10.3340/jkns.2011.49.6.351
- Author:
Hyoung Joon CHUN
1
;
Koang Hum BAK
Author Information
1. Department of Neurosurgery, Hanyang University Medical Center, Seoul, Korea. pkh2325@hanyang.ac.kr
- Publication Type:Original Article
- Keywords:
Atlantoaxial instability;
C2 pedicle screw;
Entry point;
Technique
- MeSH:
Ganglion Cysts;
Humans;
Ligaments;
Magnetic Resonance Imaging;
Mandrillus;
Neuralgia;
Spinal Canal;
Spinal Cord;
Vertebral Artery
- From:Journal of Korean Neurosurgical Society
2011;49(6):351-354
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVE: This investigation was conducted to evaluate a new, safe entry point for the C2 pedicle screw, determined using the anatomical landmarks of the C2 lateral mass, the lamina, and the isthmus of the pars interarticularis. METHODS: Fifteen patients underwent bilateral C1 lateral mass-C2 pedicle screw fixation, combined with posterior wiring. The C2 pedicle screw was inserted at the entry point determined using the following method : 4 mm lateral to and 4 mm inferior to the transitional point (from the superior end line of the lamina to the isthmus of the pars interarticularis). After a small hole was made with a high-speed drill, the taper was inserted with a 30 degree convergence in the cephalad direction. Other surgical procedures were performed according to Harm's description. Preoperatively, careful evaluation was performed with a cervical X-ray for C1-C2 alignment, magnetic resonance imaging for spinal cord and ligamentous structures, and a contrast-enhanced 3-dimensional computed tomogram (3-D CT) for bony anatomy and the course of the vertebral artery. A 3-D CT was checked postoperatively to evaluate screw placement. RESULTS: Bone fusion was achieved in all 15 patients (100%) without screw violation into the spinal canal, vertebral artery injury, or hardware failure. Occipital neuralgia developed in one patient, but this subsided after a C2 ganglion block. CONCLUSION: C2 transpedicular screw fixation can be easily and safely performed using the entry point of the present study. However, careful preoperative radiographic evaluation, regardless of methods, is mandatory.
