Comparative Study between a Curved and a Wedge PEEK Cage for Single-level Anterior Cervical Discectomy and Interbody Fusion

Kim, Hwan Soo; Song, Joon Suk; Heo, Weon; Cha, Jae Hoon; Rhee, Dong Youl

Abstract

OBJECTIVE
This study evaluated the efficiency of a curved polyetheretherketone (PEEK) cage in comparison with a wedge PEEK cage according to radiologic and clinical outcomes in patients with cervical degenerative disease.
METHODS
A total of 37 patients who suffering from cervical disc disease with radiculopathy or myelopathy were reviewed retrospectively. Seventeen patients were underwent anterior cervical discectomy and interbody fusion with a curved shape PEEK cage (curved cage group), and twenty patients with wedge shape PEEK cage (wedge cage group). Clinical assessment was graded using Odom's criteria, NDI score and VAS score. For radiologic analysis, disc height (DH), segmental angle (SA), subsidence were measured at the preoperative and last follow up.
RESULTS
A comparison of the preoperative and postoperative results revealed improvements after the surgery in the DH and SA in both cage groups. The change of postoperative DH between the preoperative and the last follow-up in wedge cage group and curved cage group was 6.85% and 25.5%, respectively. The change of postoperative SA was 1.75degrees and 0.95degrees, respectively. There was no statistically significant difference in the DH and SA between the 2 groups. The subsidence rate in the wedge cage group and curved cage group was 20% and 6%, respectively.
CONCLUSION
The 2 different cage groups showed significant improvements in the disc height, segmental angle and clinical outcomes. However, the shape of PEEK Cage influences the tendency for subsidence. Increasing contact surface area and fitting into two adjacent vertebral body prevent significant subsidence.