jkss Journal of Korean Society of Spine Surgery Journal of Korean Spine Surg 2093-4378 2093-4386 Korean Society of Spine Surgery 10.7469/JKSS.2009.16.4.251 jkss-16-251 Original Research More Than 5 Year Follow-Up of Thoracolumbar Fractures Treated By Pedicle Screw Fixation ShinByung-JoonM.D. LeeJae-ChulM.D. KimYon-IlM.D. LeeJae-SangM.D. Department of Orthopaedic Surgery, Soonchunhyang University College of Medicine, Seoul, Korea Address reprint requests to Jae-Chul Lee, M.D. Department of Orthopaedic Surgery, Soonchunhyang University College of Medicine, Seoul, Korea Tel: 82-2-709-9808, Fax: 82-2-794-9414, E-mail: jlee@hosp.sch.ac.kr 1 2009 18 1 2009 16 4 251 258 14042009 27072009 Copyright © 2009 Korean Society of Spine Surgery 2009 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Study Design

This is a retrospective study.

 Objectives

We wanted to analyze the frequency of instrument breakage and the long term reduction loss for patients who received pedicle screw fixation for thoracolumbar fractures. Summary of the Literature Review: A pedicle screw fixation system for thoracolumbar fractures has become popular since the late 1980s, but it is difficult to find articles mentioning its mid and long term results.

 Materials and Methods

Twenty-seven patients those received pedicle screw fixation for thoracolumbar fractures and dislocations and who were followed up more than 5 years were included. The average follow-up period was 139.0 months. We compared the anterior column height, the kyphotic angle and the local kyphotic angle on serial radiographs, and we measured the changes of the intervertebral disc height and the changes of the angle between screws. We also investigated the breakage and loosening of instruments.

 Results

The breakage of screws was observed in 11 cases (40.7%) and it had a statistical correlation with the loss of the lower intervertebral disc height and the loss of angles between the screws. During the follow-up, the kyphotic angle, the upper and lower disc height and the interscrew angle were decreased over time, whereas the anterior column height and wedge angle of the vertebra were maintained after the operation. There was no statistical correlation between the breakage of instruments and the degree of lower back pain.

 Conclusions

On the mid and long-term follow-up of the patients who were treated by pedicle screws for thoracolumbar fractures, the correction of the kyphotic angle was lost over time and breakage of screws may eventually occur. The loss of the kyphotic angle was mainly due to the continuous loss of the intervertebral disc height.

 Thoracolumbar Fracture Pedicle screw fixation Breakage Loss of correction REFERENCES Denis F The three column spine and its significance in the classification of acute thoracolumbar spinal injuries Spine 1983 8 817831 McAfee PC Yuan HA Fredrickson BE Lubicky JP The value of computed tomography in thoracolumbar fractures. An analysis of one hundred consecutive cases and a new classification J Bone Joint Surg Am 1983 65 461473 Sjo¨stro¨m L Jacobsson O Karlstro¨m G Pech P Rauschning W CT analysis of pedicles and screw tracts after implant removal in thoracolumbar fractures J Spinal Disord 1993 6 225231 Yue JJ Sossan A Selgrath C The treatment of unstable thoracic spine fractures with transpedicular screw instrumentation: a 3-year consecutive series Spine 2002 27 27822787 Mahar A Kim C Wedemeyer M Short-segment fixation of lumbar burst fractures using pedicle fixation at the level of the fracture Spine 2007 32 15031507 Carl AL Tromanhauser SG Roger DJ Pedicle screw instrumentation for thoracolumbar burst fractures and fracture-dislocations Spine 1992 17 317324 Knop C Fabian HF Bastian L Blauth M Late results of thoracolumbar fractures after posterior instrumentation and transpedicular bone grafting Spine 2001 26 8899 McLain RF Burkus JK Benson DR Segmental instrumentation for thoracic and thoracolumbar fractures: prospective analysis of construct survival and five-year follow-up Spine J 2001 1 310323 McLain RF Sparling E Benson DR Early failure of short-segment pedicle instrumentation for thoracolumbar fractures. A preliminary report J Bone Joint Surg Am 1993 75 162167 Wang XY Dai LY Xu HZ Chi YL Kyphosis recurrence after posterior short-segment fixation in thoracolumbar burst fractures J Neurosurg Spine 2008 8 246254 Butler JS, Walsh A, O'Byrne J Functional outcome of burst fractures of the first lumbar vertebra managed surgically and conservatively Int Orthop 2005 29 5154 Blumenthal SL Gill K Can lumbar spine radiographs accurately determine fusion in postoperative patients? Correlation of routine radiographs with a second surgical look at lumbar fusions Spine 1993 18 11861189 Dai LY, Yao WF, Cui YM, Zhou Q Thoracolumbar fractures in patients with multiple injuries: dagnosis and treatment J Trauma 2004 56 348355 Cinotti G Rocca CD Romeo S Vittur F Toffanin R Trasimeni G Degenerative changes of porcine intervertebral disc induced by vertebral endplate injuries Spine 2005 30 174180 Osti OL Vernon-Roberts B Fraser RD 1990 Volvo Award in experimental studies. Anulus tears and intervertebral disc degeneration. An experimental study using an animal model Spine 1990 15 762767 Daniaux H Transpedicular repositioning and spongio-plasty in fractures of the vertebral bodies of the lower thoracic and lumbar spine Unfallchirurg 1986 89 197213 Karl R Megan W Anna M Zachary V Clinical and radiographic results after implant removal in idiopathic scoliosis Spine 2007 32 21842188 Andress HJ Braun H Helmberger T Schu¨rmann M Hertlein H Hartl WH Long-term results after posterior fixation of thoracolumbar burst fractures Injury 2002 33 357365 Louis CA Gauthier VY Louis RP Posterior approach with Louis plates for fractures of the thoracolumbar and lumbar spine with and without neurologic deficits Spine 1998 23 20302040 Shen WJ Liu TJ Shen YS Nonoperative treatment versus posterior fixation for thoracolumbar junction burst fractures without neurologic deficit Spine 2001 26 10381045 Leferink VJ Zimmerman KW Veldhuis EF ten Verg-ert EM ten Duis HJ Thoracolumbar spinal fractures: radiological results of transpedicular fixation combined with transpedicular cancellous bone graft and posterior fusion in 183 patients Eur Spine J 2001 10 517523 Figures

Relative heights of body and disc.

Measuring methods of kyphotic and screw angle. α : kyphotic angle β: interscrew angle

Preoperative radiograph shows burst fracture of L2 vertebra. (B) Immediate postoperative radiograph shows a good correction of kyphosis by posterior instrumented fusion. (C) On postoperative 6 year radiograph, decrease of upper and lower disc height and breakage of lower pedicle screws.

Changes of anterior body height of fractured vertebra (B) Changes of kyphotic angle of fractured vertebra (C) Changes of wedge angle of fractured vertebra (D) Changes of upper disc height of fractured vertebra (E) Changes of lower disc height of fractured vertebra (F) Changes of interpedicular angle of fractured vertebra. Total : whole patients, None: patients without screw breakage, Failure: patients with pedicle screw breakage.