Increased sagittal diameter of the vertebral arch aids in diagnosis of lumbar spondylolysis

Shi-Zheng Chen,He-Hu Tang,Zhen Lv,Jun-Wei Zhang,An-Ni Tong,Shu-Jia Liu,Jie-Sheng Liu

doi:10.1007/s00256-020-03658-8

Abstract

ObjectiveTo identify a diagnostic indicator of lumbar spondylolysis visible in plain X-ray films.MethodsOne hundred and seventy-two patients with low back pain who received X-ray and computerized tomography (CT) examinations were identified and studied. They were divided into three groups: the spondylosis without spondylolisthesis (SWS) group, comprising 67 patients with bilateral pars interarticularis defects at L5 and without spondylolisthesis, the isthmic spondylolisthesis (IS) group, comprising 74 patients with L5/S1 spondylolisthesis and bilateral L5 pars interarticularis defects, and the control group, comprising 31 patients with low back pain but without spondylolysis. The sagittal diameters of the vertebral arch (SDVAs) of L4 and L5 were measured in lateral X-ray image, and the differences in SDVA between L4 and L5 (DSL4-5) in each case were calculated and analyzed.ResultsThere were no significant differences in demographic characteristics among the three groups. In the SWS and IS groups, the SDVA of L5 was significantly longer than the SDVA of L4 (p < 0.001), whereas no significant difference found in the control group (p > 0.05). DSL4-5, in which the SDVA of L4 was subtracted from the SDVA of L5, significantly differed among the three groups (p < 0.001), and the normal threshold was provisionally determined to be 1.55 mm.ConclusionsIn bilateral L5 spondylolysis, the SDVA of L5 is wider than the SDVA of L4, and this difference is greater in isthmic spondylolisthesis. This sign in lateral X-rays may provide a simple and convenient aid for the diagnosis of spondylolysis.

Highlights

Spondylolysis, derived from the Greek words spondylos and lysis [1,2,3], is defined as a unilateral or bilateral defect or abnormality of the pars interarticularis and surrounding lamina and pedicle
Sixtyseven patients (36 males and 31 females; age, median ± interquartile range, 47.0 ± 17.0 years) with bilateral pars interarticularis defects (PID) only at L5, but without spondylolisthesis, were placed in the spondylosis without spondylolisthesis (SWS) group; 74 patients (38 males and 36 females; age: 54.0 ± 18.5 years) with L5/S1 spondylolisthesis and bilateral L5 PID were placed in the isthmic spondylolisthesis (IS) group and 31 patients (19 males and 12 females, age: 58.0 ± 26.0 years) with low back pain (LBP) but no abnormalities in lumbar spine images were classified as the control group (Table 1)
To demonstrate the contribution of differences in sagittal diameter of the vertebral arch (SDVA) between L4 and L5 (DSL4-5) to the diagnosis of spondylolysis, we reviewed all the images once more, divided the patients into two groups on the basis of L4 bilateral PID being directly seen or not seen on the plain X-ray films

Summary

Introduction

Spondylolysis, derived from the Greek words spondylos (vertebra) and lysis (defect) [1,2,3], is defined as a unilateral or bilateral defect or abnormality of the pars interarticularis and surrounding lamina and pedicle. Physicians often order a lumbar X-ray as the primary imaging test. This test may provide direct or indirect evidence of structural lesions in the lumbar spine. If a deformity is found in the X-rays, such as narrowing of the intervertebral space, spondylolysis, or osteoporosis, a diagnosis can be Skeletal Radiol (2021) 50:1125–1130 made. These signs may be absent, and pars interarticularis defects (PID) are often difficult to see in Xrays, especially if there is no spondylolisthesis, in which case the patients are likely to be scheduled for further imaging, such as CT and MRI. The aim of our study was to identify a diagnostic indicator of lumbar spondylolysis visible on plain X-ray films

Methods

Results

Conclusion