[Correlation between the 4th lumbar degenerative spondylolisthesis and radiographic parameters]

To investigate the relationship between radiographic parameters and the 4th lumbar(L4) degenerative spondylolisthesis.

From April 2010 to April 2012, 60 patients with the L 4 degenerative spondylolisthesis (DLS) were enrolled in DLS group, 56 healthy volunteers were recruited in control group. A series of radiographic parameters were measured in the two groups, including disc height (DH), disc degeneration index(DDI), L4 vertebral inclination angle(L4-VA), pelvic incidence (PI), L4 vertebral size (L4-VS), lumbar lordosis angle (LLA), facet joint angulation (FJA) of cephalad and caudad portions, delta FJA of cephlad and caudad portions, asymmetry variation of FJA, bone mineral density(BMD). Student's test was used to compare difference of parameters between two groups. Multivariate logistic regression analysis was used to reveal risk factors of the development of DLS.

Fifty-three cases of L4 spondylolisthesis in DLS group were classified into grade I, 7 cases of L4 spondylolisthesis were classified into grade II. The average Boxall index was 0.17 ± 0.05. There were significant difference of DH, DDI, L4-VS, L4-VA, LLA, PI, FJA, BMD between DLS group and control group (t = 2.28-9.33, P = 0.021-0.043) . There were significant differences of delta FJA of cephlad and caudad portions in L3-4, L4-5 between DLS group and control group (t = 3.398 and 28.122, P = 0.000 and 0.039). There was no significant difference of asymmetry variation of FJA in L3-4, L4-5 between DLS group and control group (t = 0.209-0.465, P = 0.295-0.858). Multivariate logistic regression analysis showed that LDS was more frequent among patients with smaller L4-VS(OR = 1.01, 95%CI = 1.000-1.024, P = 0.048), larger L4-VA (OR = 1.88, 95%CI = 14.000-14.600, P = 0.037), larger LLA (OR = 1.90, 95%CI = 1.600-15.800, P = 0.040), larger PI (OR = 2.58, 95%CI = 18.000-19.600, P = 0.029) and the more sagittal FJA (OR = 2.46, 95%CI = 1.400-16.400, P = 0.035) than those in control group.

DLS is signifantly correlated with L4-VS, L4-VA, LLA, PI, FJA . They may be risk factors of the development of DLS.