1. Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized commercial reproduction of this slide is prohibited Supplemental PowerPoint Slides Clinical Significance of Achieving a Flexion Limitation with a Tension Band System in Grade 1 Degenerative Spondylolisthesis: a minimum 5- year follow-up Sang-Ho Lee, MD, PhD,* Ho-Yeon Lee, MD, PhD,* Oon Ki Baek, MD, PhD, † Jun Seok Bae, MD,* Seung-Hwa Yoo, ME,‡ and June-Ho Lee, MD* Department of *Neurosurgery, Wooridul Spine Hospital, Seoul, Korea Department of †Neurosurgery, Daegu Wooridul Spine Hospital, Daegu, Korea ‡Wooridul Institute for Biomedical Science and Technology, Seoul, Korea

2. C D A B A and C, Preoperative flexion radiographs of patients in the flexion-limited group showing kyophotic derangement at the index level. D and F, Postoperative flexion radiographs of B and D, respectively. Although anterior translation progressed to some extent, the flexion kyphosis was limited. ISS with a tension band system tied through one level above and one level below the interspinous spaces in a figure-of-eight fashion. Sixty-one patients who underwent ISS following decompression for grade 1 DS with stenosis between 2002 and 2004 were analyzed. Statistically significant improvements were noted only in the flexion- limited group in all clinical scores. In the flexion-unlimited group, there were significant deteriorations in flexion angle, axial thickness of the ligamentum flavum, and the foraminal cross-sectional area. The preoperative extension angle was identified as the most influential variable for the flexion limitation and the clinical outcomes.

3. Conclusions B A D C F E H G A, C, E, and G, Preoperative sagittal MR images. B, Postoperative image of a patient in the flexion-limited group. The foraminal area remained unchanged (arrow). D, F, and H, Postoperative images of patients in the flexion-unlimited group. The narrowing of the neural foramen was due to LF hypertrophy (arrows) combined with facet osteoarthritis, a pseudo-disc bulge, and additional forward slippage of the upper vertebrae. The effects of the limitation of flexion rotation achieved through ISS using a tension band system following decompression were related to the prevention of late recurrent stenosis and resultant radicular pain caused by flexion instability. The extension potential at the index level was recognized as a major prognostic factor that can predict the flexion limitation and the clinical results.