@article{oai:niigata-u.repo.nii.ac.jp:00006218,
 author = {Takano, Ko and Hasegawa, Kazuhiro and Kitahara, Ko and Hara, Toshiaki and Sato, Sakae and Endo, Naoto},
 issue = {1},
 journal = {Acta medica et biologica, Acta medica et biologica},
 month = {Mar},
 note = {In vivo quantitative evaluation of lumbar segmental stability has not been established yet. We developed a new measurement system to determine intraoperative lumbar stability. The purposes of this study were to measure in vivo segmental stability and to clarify the relationships between the preoperative radiographic findings and intraoperative measurement parameters. The system consisted of spinous process holders, a motion generator, load cell, optical displacement transducer, and computer. A cyclic displacement (2.0mm/s, 15mm max displacement) of the holders produced flexion-extension with all ligamentous structures intact. Intraoperative measurement parameters, including stiffness, neutral zone (NZ), and absorption energy (AE), were determined via load-deformation data. Twenty lumbar segments in 19 patients (M/F=10/9, mean age 59.3 years, range 21-83 years) with degenerative lumbar disease were studied. Range of motion (ROM) and horizontal displacement (HD) were determined from lateral functional X-ray using the method by Dupuis et al. Magnetic resonance images of all discs were categorized into Thompson's five grades and further into three groups: None (grades 1 and 2, n=6), Mild (grade 3, n=10), and Severe (grades 4 and 5, n=4) degeneration. Relationships between the radiographic findings and the intraoperative measurement parameters were analyzed. In all cases, intraoperative measurement was completed within 10min without complications. There was no significant relationship between the radiographic findings and intraoperative measurement parameters. Stiffness in the Mild group was significantly lower than that in the other groups (None vs Mild p<0.01, Mild vs Severe p<0.05). The NZ of the Mild group was higher than that in the other groups. AE tended to be lower in the Mild group. Our measurement system established a method to determine stiffness, NZ, and AE by obtaining continuous data in vivo. There were no significant relationships between the functional radiographic results and biomechanical data, suggesting that conventional X-ray examinations cannot be used to determine segmental instability. The Mild group had less stiffness and a higher NZ than the other groups, possibly indicating "instability" in patients with mild disc degeneration.},
 pages = {1--8},
 title = {Lumbar Segmental Motion Properties In vivo Determined by a New Intraoperative Measurement System},
 volume = {54},
 year = {2006}
}