gms | German Medical Science

67th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Korean Neurosurgical Society (KNS)

German Society of Neurosurgery (DGNC)

12 - 15 June 2016, Frankfurt am Main

Segmental kyphosis after cervical interbody fusion with stand-alone polyetheretherketone (PEEK) cages: A comparative study of two different PEEK cages

Meeting Abstract

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  • Chi Heon Kim - Seoul National University Hospital, Korea
  • Chun Kee Chung - Seoul National University Hospital, Korea
  • Won Heo - Seoul National University Hospital, Korea

Deutsche Gesellschaft für Neurochirurgie. 67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 1. Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS). Frankfurt am Main, 12.-15.06.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocP 065

doi: 10.3205/16dgnc440, urn:nbn:de:0183-16dgnc4405

Published: June 8, 2016

© 2016 Kim et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Objective: Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion (ACDF). Although polyetheretherketone (PEEK) material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design. Two PEEK cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion.

Method: A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round-tube type (Solis™, 18 patients, S-group) or a trapezoidal-tube type (MC+®, 23 patients, M-group) cage was used. The contact area between cage and the vertebral body is larger in MC+ than Solis, and anchoring pins were present in Solis cage. The effect of the cage type on the segmental angle (lordosis vs. kyphosis) at postoperative month 24 was analyzed.

Results: Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (p = 0.84). The segmental angle was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (p = 0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (p = 0.01). The patients in M-group were 7.83 times more likely than patients in S-group (p = 0.04; OR, 7.83; 95% CI, 1.09 - 56.28) not to develop segmental kyphosis.

Conclusions: The design of the PEEK cage used may influence the segmental angle, and this association needs to be considered when using stand-alone PEEK cages.