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Morphological Characteristics of Cervical Spine in Patients With Athetoid Cerebral Palsy and the Accuracy of Pedicle Screw Placement

Kato, So MD*; Shoda, Naoki MD*; Chikuda, Hirotaka MD, PhD*; Seichi, Atsushi MD; Takeshita, Katsushi MD, PhD*

doi: 10.1097/BRS.0000000000000234
Cervical Spine
SLIDE

Study Design. A retrospective study.

Objective. To investigate the morphology of the cervical spine in patients with athetoid cerebral palsy (CP), and to evaluate its relationship with the breach of cervical pedicle screws.

Summary of Background Data. Cervical pedicle screws have been increasingly used in surgery for patients with CP, but screw misplacement is not uncommon. Although the altered morphology of the cervical spine in patients with CP may result in this high breach rate, few studies have examined the cervical pedicle profile.

Methods. We retrospectively analyzed 31 patients with cervical myelopathy with CP, as well as 30 patients with cervical spondylotic myelopathy (CSM), who underwent posterior decompression surgery. The pedicle outer diameter, inner diameter, transverse angle and lateral mass deformity were investigated by obtaining preoperative computed tomographic scans. The accuracy of the placement of 56 pedicle screws used in fusion surgery for 12 patients with CP was also analyzed using postoperative computed tomographic scans.

Results. The outer diameter of the pedicle in CP was in the range from 3.3 to 9.6 mm, and was larger than that in CSM at all cervical levels except for C7. Pedicle sclerosis was more frequently observed in CP than in CSM (23% vs. 7.3%, P < 0.001). The transverse angle at C3 and C4 was larger, and lateral mass deformity was more frequently observed in CP than in CSM. The critical breach of pedicle screws in CP was found in 29%. A multivariate analysis revealed that pedicle sclerosis was associated with an increased risk of breach (odds ratio: 6.3; 95% confidence interval: 1.03–39.0; P = 0.047).

Conclusion. The pedicle diameter in patients with CP was relatively large, but pedicle sclerosis, a wide transverse angle and lateral mass deformity were frequently observed. Sclerotic pedicles were associated with a higher risk of critical breach.

Level of Evidence: N/A

This retrospective analysis of the computed tomographic scans of 31 patients with athetoid cerebral palsy and 30 patients with cervical spondylotic myelopathy who underwent decompression surgery elucidated that the pedicle outer diameter was larger in patients with cerebral palsy and that pedicle sclerosis was associated with an increased risk of screw misplacement.

*Department of Orthopaedic Surgery, Sensory and Motor System Medicine, Surgical Sciences, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan; and

Department of Orthopaedics, Jichi Medical University, Shimotsuke, Japan.

Address correspondence and reprint requests to So Kato, MD, Department of Orthopaedic Surgery, Sensory and Motor System Medicine, Surgical Sciences, Graduate School of Medicine, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-8655, Japan; E-mail: skatou-tky@umin.org

Acknowledgment date: July 31, 2013. Revision date: November 13, 2013. Acceptance date: January 9, 2014.

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

No relevant financial activities outside the submitted work.

© 2014 by Lippincott Williams & Wilkins