| Objective This study was designed to observe in vivo segmental lumbar motion between symptomatic L4 isthmic spondylolisthesis(IS) patients and L4 degenerative spondylolisthesis(DS) patients during functional weight-bearing activities, provide the theoretical basis for the clinical diagnosis, the treatment and the proper operation in patients with lumbar spondylolisthesis.Methods Fifteen symptomatic L4 IS patients(mean age 53) and fifteen symptomatic L4 DS patients(mean age 55) were recruited. Fifteen asymptomatic volunteers(mean age 54) compared as control group. The L3-S1 vertebral segment motion of each subject was reconstructed using three-dimensional computed tomography and a solid modeling software. In vivo lumbar vertebral motion during functional postures(flexion-extension left-right twisting and left-right bending) was observed using a dual fluoroscopic imaging technique. Local coordinate systems were established at the center of L3-S1 vertebral body and the posterior segment of the isthmic spondylolisthesis laminar, to obtain the 6 degree-of-freedom(DOF) intervertebral range of motion(ROM) at L3-4, L4-5 and L5-S1, the ROM between the anterior and the posterior segments of L4 IS.Results 1.The motion pattern at L4/5 with IS was found to be altered. During flexion to extension the migration along sagittal axis was significantly larger than DS group(P 0.05); the migration along vertical axis was significantly larger than normal group(P 0.05). During left-right twisting the migration along sagittal axis was significantly larger than normal group(P 0.05);the rotation along vertical axis were significantly larger than DS and normal groups(P 0.05). During left-right bending the migration along frontal axis were significantly larger than DS and normal group(P 0.05). The intervertebral ROM at L4/5 was no significant difference between DS and normal group. 2. The motion pattern at L3/4 with DS was found to be altered. During left-right bending the rotation along sagittal axis were 4.4 2.8, significantly larger than normal group 2.1 1.7(P 0.05). During left-right twisting the rotation along vertical axis were 4.3 2.8, significantly larger than normal groups 2.1 1.3(P 0.05). During flexion to extension the rotation along frontal axis was 3.9 3.3, larger than DS group 3.2 2.5,but the difference was not significant. However, the motion pattern at L4/5 and L5/S1 with DS were found no significantly difference compared with normal groups. The normal group in L3-4 during flexion-extension, left twist-right twist and left bend-right bend, L5-S1 in left twist-right twist and left bend-right bend, the main motion had increased trend compared with coupled motion, but the trend of spondylolysis group disappeared; during flexion-extension, the main motion of the normal group in L5-S1 had decreased trend compared with coupled motion because of the facet joint oriented more coronal, but the trend of spondylolysis group disappeared. The IS group in L3-4 during flexion-extension, left twist-right twist and left bend-right bend existed translational instability compared with normal group(P 0.05); also the angulations of the IS group in L5-S1 significantly decreased(P 0.05). 3. AIS with respect to PIS, the separation along the sagittal axis at flexion was significantly larger than at standing, and the separation along the coronal axis at standing was significantly larger than at supine.Conclusions A spondylolytic defect does lead to detectable instability or hypermobility in the lumbar spine compared with degenerative spondylolisthesis and normal group, discovered the existence of anterioposterior displacement along sagittal axis from standing to flexion and mediolateral displacement along the coronal axis from supine to standing between the anterior and the posterior segments of L4 isthmic spondylolisthesis. The slipped segments of degenerative spondylolisthesis is stable, however, the ROM of the cranial segment increased. The mode of adjacent segment motion in patients with spondylolisthesis disturbed. DS had angulation instability based at the cephalic segment in L3-4, while IS mainly showed displacement instability; DS did not exist excessive activity at caudal segment in L5-S1, while the angulations of the IS group in L5-S1 decreased significantly. |
PDF Full Text Request