Biomechanical evaluation of segmental instability in degenerative lumbar spondylolisthesis.

Autor: Hasegewa K; Niigata Spine Surgery Center, 2-5-22 Nishi-machi, Niigata 950-0165, Japan. kazu3795jp@yahoo.co.jp, Kitahara K, Hara T, Takano K, Shimoda H
Jazyk: angličtina
Zdroj: European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society [Eur Spine J] 2009 Apr; Vol. 18 (4), pp. 465-70. Date of Electronic Publication: 2008 Dec 10.
DOI: 10.1007/s00586-008-0842-3
Abstrakt: Here we investigated the biomechanical properties of spinal segments in patients with degenerative lumbar spondylolisthesis (DLS) using a novel intraoperative measurement system. The measurement system comprised spinous process holders, a motion generator, a load cell, an optical displacement transducer, and a computer. Cyclic displacement of the holders produced flexion-extension of the segment with all ligamentous structures intact. Stiffness, absorption energy (AE), and neutral zone (NZ) were determined from the load-deformation data. Forty-one patients with DLS (M/F = 15/26, mean age 68.6 years; Group D) were studied. Adjacent segments with normal discs in six patients (M/F = 3/3, mean age 35 years) were included as a control group (Group N). Flexion stiffness was significantly lower in Group D than in Group N. The NZ, however, was significantly greater in Group D than in Group N. Thus, compared to normal segments, spinal segments with DLS had a lower flexion stiffness and a higher NZ. NZs in Group D were, however, widely distributed compared to those in Group N that showed NZ <2 mm/N in all cases, suggesting that the segment with DLS is not always unstable and that the segments with NZ >2 mm/N can be considered as unstable.
Databáze: MEDLINE