The Dynesys dynamic stabilization (DDS) system is considered a motion-preserving device. However, studies addressing the change in the range of motion (ROM) are limited. Therefore, this study aimed to investigate the factors influencing ROM change at the index surgical level, supra-index level, and whole lumbar spine, in addition to the association between ROM preservation and the incidence of screw-loosening.
Decompression with instrumented fusion is an effective surgical intervention for lumbar degenerative spondylolisthesis with spinal stenosis. However, the range of motion (ROM) decreased at the index surgical level may lead to an increased ROM at the non-surgical level, increase biomechanical stress at the transitional adjacent segment, and lead to adjacent segment degeneration (ASD) . The Dynesys dynamic stabilization (DDS) system is a pedicle screw-based, motion-preserving, and non-fusion stabilization developed as an alternative to the rigid instrumented fusion for degenerative spondylolisthesis. The aim of the DDS is to maintain segmental motion at index levels and to reduce the incidence of ASD. However, the actual impact of ROM has remained elusive. Prior studies have reported an average ROM loss of 1.1º to 17.3º 7 at index surgical level at an average of 24 months follow-up. The change of ROM at index surgical, supra-index, and whole lumbar spine following DDS remains unclear. This study aims to investigate the factors influencing the ROM change at index surgical level, supra-index level, and whole lumbar spine, and the association between ROM preservation and the incidence of screw-loosening.
Study Type
OBSERVATIONAL
Enrollment
139
All surgeries were performed by a senior surgeon using a traditional midline approach. Stability-preserving lumbar decompression with facet joint undercutting was performed to preserve the facet joints as much as possible. In cases of severe stenosis, a bilateral partial facetectomy (\< 25%) was performed for adequate decompression. Posterior tension of the supra- and inter-spinous ligaments was preserved at the most cranial level. Patients were encouraged to ambulate after drain removal and wear a soft lumbar orthosis for at least 3 months after the operation.
Dep. of Orthopedics and Traumatology, Taipei Veterans General Hospital
Taipei, Taiwan
Range of motion
The ROM change at index surgical level, supra-index level, and whole lumbar spine in degenerative lumbar diseased patients received dynesys dynamic instrumentation
Time frame: All patients completed the follow-up assessment at postoperative 1-, 2-, 3-, 6-, 12-, and 24-months.
Screw loosening
Radiographic screw-loosening was defined as presence of a halo or double-halo sign on plain x-ray films
Time frame: All patients completed the follow-up assessment at postoperative 1-, 2-, 3-, 6-, 12-, and 24-months.
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