Document Detail


Radiostereometric analysis of postoperative motion after application of dynesys dynamic posterior stabilization system for treatment of degenerative spondylolisthesis.
MedLine Citation:
PMID:  20072031     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY DESIGN: Prospective case series OBJECTIVE: This was designed to precisely measure motion after posterior dynamic stabilization using Dynesys instrumentation. SUMMARY OF BACKGROUND DATA: The Dynesys posterior dynamic stabilization system, which stabilizes the spinal segment while potentially decreasing the risk of adjacent segment disease, is undergoing evaluation by the US Food and Drug Administration for treatment of degenerative spondylolisthesis without fusion. Evaluation of adjacent segment disease requires precise characterization of motion on the surgical level. Unfortunately, routine clinical radiographic techniques are imprecise and unreliable for full characterization of spinal segment motion. Radiostereometric analysis, which is very precise and reliable for in vivo measurement of motion, was used to examine spinal segment motion after dynamic stabilization with Dynesys. METHODS: Six patients (age 59+/-7 y) underwent posterior decompression followed by posterior stabilization using Dynesys instrumentation (4 one-level, 2 two-levels). Three to 5 tantalum beads were placed in each vertebral body. Postoperative biplanar radiographs were obtained in flexion, extension, right, and left lateral bending, and 3-dimensional reconstruction was performed using radiostereometric analysis at 3, 6, 12, and 24 months postoperatively. The translations and rotations of the superior vertebral body were measured relative to the inferior vertebral body. RESULTS: Over the 24-month follow-up period, mean flexion, extension, left, and right lateral bending of the motion segments were noted to be 1.0 degrees, 2.4 degrees, 0.6 degrees, and 0.6 degrees or less, respectively. There were no statistically significant changes in the degree of motion. During follow-up, no significant changes in neutral position of the device were noted in any of the 3 planes, and minimal translation was noted in the postoperative period. CONCLUSIONS: The Dynesys dynamic instrumentation system seems to stabilize degenerative spondylolisthesis. As expected in the degenerative lumbar spine, the segmental motion of the implanted level in this study was limited and considerably less than normal spinal motion.
Authors:
Amir H Fayyazi; Nathaniel R Ordway; Soo-An Park; Bruce E Fredrickson; Kenneth Yonemura; Hansen A Yuan
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of spinal disorders & techniques     Volume:  23     ISSN:  1539-2465     ISO Abbreviation:  J Spinal Disord Tech     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-06-07     Completed Date:  2010-09-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101140323     Medline TA:  J Spinal Disord Tech     Country:  United States    
Other Details:
Languages:  eng     Pagination:  236-41     Citation Subset:  IM    
Affiliation:
Penn State College of Medicine, Center for Advanced Healthcare, PA, USA. amirfayyazi@yahoo.com
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MeSH Terms
Descriptor/Qualifier:
Aged
Decompression, Surgical / methods
Female
Humans
Lumbar Vertebrae / radiography,  surgery*
Male
Middle Aged
Prospective Studies
Range of Motion, Articular*
Recovery of Function
Spinal Fusion / methods
Spondylolisthesis / radiography,  surgery*
Treatment Outcome

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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