Chao Tang, Ye Hui Liao, Qiang Tang, Fei Ma, Qing Wang, De Jun Zhong

August 2021, Volume 30, Issue 8, pp 2301 - 2310 Original Article Read Full Article 10.1007/s00586-021-06884-3

First Online: 28 May 2021

What is the difference in pedicle morphology of the fifth lumbar vertebra between isthmic and degenerative L5-S1 spondylolisthesis? An anatomic study of 328 patients via multi-slice spiral computed tomography


The purpose of this study was to investigate and determine whether there are differences in L5 pedicles morphology between isthmic and degenerative L5–S1 spondylolisthesis.


One hundred and nineteen patients with isthmic spondylolisthesis and 45 patients with degenerative spondylolisthesis at L5–S1 were enrolled in the IS group and DS group, respectively, and 164 lumbar disc herniation patients without spondylolysis or spondylolisthesis were classified into the normal (NL) group. A series of pedicle parameters of the fifth lumbar vertebra, including pedicle length (PL), pedicle width (PW), pedicle screw trajectory length (PSTL), pedicle height (PH), and the pedicle camber angle (PCA), were measured using multi-slice spiral computed tomography (MSCT). The slip distance of the L5 vertebra was measured on radiography, and the percentage of slip was also recorded.


The pedicles of the fifth lumbar vertebra were shorter and wider, and the PCA was larger in the IS group compared to the DS group and NL group. On the contrary, the pedicles in the DS group were elongated and thinner, and the PCA was smaller. The pedicle parameters of PL were significantly positively correlated with the percentage of slip in the DS group, but PW and PCA were negatively correlated with the percentage of slip. There was no correlation between the percentage of slip and L5 pedicle parameters in the IS group.


The L5 pedicles morphology in L5–S1 isthmic spondylolisthesis shows abduction, shortness, and width, while that in the degenerative spondylolisthesis shows adduction, lengthening, and thinning compared with the normal populations. The morphology changes may be the result of pedicle stress remodelling in the development of spondylolisthesis, which should be taken into consideration when placing at the insertion of pedicle screws.

Read Full Article