Paradoxical Radiographic Changes of Coflex Interspinous Device with Minimum 2-Year Follow-Up in Lumbar Spinal Stenosis

Nam Lee, Dong Ah Shin, Keung Nyun Kim, Do Heum Yoon, Yoon Ha, Hyun Chul Shin, Seong Yi

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Objectives: Studies have yet to investigate long-term radiologic changes in lumbar spinal stenosis patients treated with interspinous device (Coflex). This study aimed to evaluate which radiologic parameters change significantly after surgery with Coflex and identify which parameter most affects the radiologic outcome. Methods: Of 101 patients with lumbar spinal stenosis treated by Coflex insertion on L4-5, the radiologic parameters of 30 patients were measured before and at least 2 years after surgery. On the basis of the development of bony erosion around Coflex, patients were divided into the erosion group (n = 14) or the nonerosion group (n = 16). Results: The mean anterior disc height (ADH) and range of motion (ROM) were significantly decreased after surgery (15.161 mm vs. 13.788 mm and 9.63° vs. 7.13°). The erosion group showed substantially higher values in preoperative ADH, postoperative posterior disc height (PDH), and intervertebral foramen height (6.52 mm vs. 8.05 mm; 5.80 mm vs. 8.03 mm; 19.20 mm vs. 21.06 mm). Postoperative ROM and ROM ratio were higher in the erosion group (5.95° vs. 8.47° and 0.659 vs. 0.938). However, only ADH showed a significant change in the erosion group after surgery (15.86 mm vs. 14.29 mm). On the contrary, ADH and PDH, as well as ROM, were significantly decreased in the nonerosion group (14.55 mm vs. 13.34 mm; 6.52 mm vs. 5.82 mm; 9.46° vs. 5.95°). Conclusion: The preoperative state including relatively higher ADH, PDH, and larger ROM could induce erosion. The long-term preservation of disc height and ROM may also induce erosion. That reduction of most radiologic parameters seems to be natural after surgery, and insufficient reduction of disc height and ROM may induce adverse effects, which can increase the possibility of spinous process fracture or device malposition.

Original languageEnglish
Pages (from-to)177-184
Number of pages8
JournalWorld Neurosurgery
Publication statusPublished - 2016 Jan 1

Bibliographical note

Funding Information:
This study was supported by a faculty research grant of Yonsei University College of Medicine for 2014 (6-2014-0189) and 2015 (6-2015-0043) , the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF-2014M3A7B4051596) , and the Yonsei University Yonsei-SNU Collaborative Research Fund of 2014.

Publisher Copyright:
© 2016 Elsevier Inc. All rights reserved.

All Science Journal Classification (ASJC) codes

  • Surgery
  • Clinical Neurology


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