Michael Ruf1, Tobias Pitzen1, Ivo Nennstiel2, David Volkheimer3, Jörg Drumm1, Klaus Püschel4, Hans-Joachim Wilke5. 1. Center for Spine Surgery, Orthopedics, and Traumatology, SRH Klinikum Karlsbad-Langensteinbach, Guttmannstrasse 1, 76307, Karlsbad, Germany. 2. Center for Orthopedic Surgery and Traumatology, SRH Central Hospital Suhl, Albert-Schweitzer-Strasse 2, 98527, Suhl, Germany. 3. Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, 89901, Ulm, Germany. 4. Department of Legal Medicine, University Hospital Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany. 5. Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, 89901, Ulm, Germany. hans-joachim.wilke@uni-ulm.de.
Abstract
PURPOSE: Surgical treatment of thoracolumbar A3-fractures usually comprises posterior fixation-in neutral position or distraction-potentially followed by subsequent anterior support. We hypothesized that additional posterior compression in circumferential stabilization may increase stability by locking the facets, and better restore the sagittal profile. METHODS: Burst fractures Type A3 were created in six fresh frozen cadaver spine segments (T12-L2). Testing was performed in a custom-made spinal loading simulator. Loads were applied as pure bending moments of ± 3.75 Nm in all six movement axes. We checked range of motion, neutral zone and Cobb's angle over the injured/treated segment within the following conditions: Intact, fractured, instrumented in neutral alignment, instrumented in distraction, with cage left in posterior distraction, with cage with posterior compression. RESULTS: We found that both types of instrumentation with cage stabilized the segment compared to the fractured state in all motion planes. For flexion/extension and lateral bending, flexibility was decreased even compared to the intact state, however, not in axial rotation, being the most critical movement axis. Additional posterior compression in the presence of a cage significantly decreased flexibility in axial rotation, thus achieving stability comparable to the intact state even in this movement axis. In addition, posterior compression with cage significantly increased lordosis compared to the distracted state. CONCLUSION: Among different surgical modifications tested, circumferential fixation with final posterior compression as the last step resulted in superior stability and improved sagittal alignment. Thus, posterior compression as the last step is recommended in these pathologies.
PURPOSE: Surgical treatment of thoracolumbar A3-fractures usually comprises posterior fixation-in neutral position or distraction-potentially followed by subsequent anterior support. We hypothesized that additional posterior compression in circumferential stabilization may increase stability by locking the facets, and better restore the sagittal profile. METHODS: Burst fractures Type A3 were created in six fresh frozen cadaver spine segments (T12-L2). Testing was performed in a custom-made spinal loading simulator. Loads were applied as pure bending moments of ± 3.75 Nm in all six movement axes. We checked range of motion, neutral zone and Cobb's angle over the injured/treated segment within the following conditions: Intact, fractured, instrumented in neutral alignment, instrumented in distraction, with cage left in posterior distraction, with cage with posterior compression. RESULTS: We found that both types of instrumentation with cage stabilized the segment compared to the fractured state in all motion planes. For flexion/extension and lateral bending, flexibility was decreased even compared to the intact state, however, not in axial rotation, being the most critical movement axis. Additional posterior compression in the presence of a cage significantly decreased flexibility in axial rotation, thus achieving stability comparable to the intact state even in this movement axis. In addition, posterior compression with cage significantly increased lordosis compared to the distracted state. CONCLUSION: Among different surgical modifications tested, circumferential fixation with final posterior compression as the last step resulted in superior stability and improved sagittal alignment. Thus, posterior compression as the last step is recommended in these pathologies.
Authors: Ory Keynan; Charles G Fisher; Alexander Vaccaro; Michael G Fehlings; F C Oner; John Dietz; Brian Kwon; Raj Rampersaud; Christopher Bono; John France; Marcel Dvorak Journal: Spine (Phila Pa 1976) Date: 2006-03-01 Impact factor: 3.468
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Authors: Stephanus V Viljoen; Nicole A DeVries Watson; Nicole M Grosland; James Torner; Brian Dalm; Patrick W Hitchon Journal: J Neurosurg Spine Date: 2014-08-01