The comparison of measurement between ultrasound and computed tomography for abnormal degenerative facet joints: A STROBE-compliant article

Abstract

Besides the study on examining facet joints of lumbar spine by ultrasound in normal population, there has not been any related report about examining normal facet joints of lumbar spine by ultrasound so far. This study was aimed to explore the feasibility of ultrasound assessment of lumber spine facet joints by comparing ultrasound measure values of normal and degenerative lumber spine facet joints, and by comparing measure values of ultrasound and computed tomography (CT) of degenerative lumber spine facet joints.This study included 15 patients who had chronic low back pain because of degenerative change in lumbar vertebrae, and 19 volunteers who did not have low back pain or pain in the lower limb. The ultrasound measure values (height [H] and width [W]) of normal and degenerative lumber spine facet joints were compared. And the differentiation between measure values (H and W) of ultrasound and CT of degenerative lumber spine facet joints was also analyzed.The ultrasound clearly showed abnormal facet joints lesion, which was characterized by hyperostosis on the edge of joints, bone destruction under joints, and thinner or thicker articular cartilage. There were significant differences between the ultrasound measure values of the normal (H: 1.26 ± 0.03 cm, W: 0.18 ± 0.01 cm) and abnormal facet joints (H: 1.43 ± 0.05 cm, W: 0.15 ± 0.02 cm) (all P < .05). However, there were no significant differences between the measure values of the ultrasound (H: 1.43 ± 0.17 cm, W: 0.15 ± 0.03 cm) and CT (H: 1.42 ± 0.16, W: 0.14 ± 0.03) of the degenerative lumber spine facet joints (all P > .05).Ultrasound can clearly show the structure of facet joints of lumbar spine. It is precise and feasible to assess facet joints of lumbar spine by ultrasound. This study has important significance for the diagnosis of lumbar facet joint degeneration.

Figure 1

Sonogram of facet joints. (A) Schematic representation of the facet joint in sagittal plane. Black line: parasagittal line. (B) Facet joint of sonography in the parasagittal plane of the facet joint is the greatest dimension from the cranial (line a) to the caudal point (line b) of the hypoechogenic layer between the inferior and superior articular processes.(C) Facet joint of sonography in the transverse plan. W of the hypoechogenic layer is the greatest dimension perpendicular to the facet joints surfaces of inferior and superior articular processes. H = height, W = width.

Figure 2

CT image of facet joints. (A) Facet joint of the CT imaging in the parasagittal plane. Parameter of H of the facet joint was defined as the greatest dimension from the cranial (line a) to the caudal point (line b) between the inferior and superior articular processes. (B) Facet joint of CT imaging in the transverse plan. W of the facet joint was the greatest dimension perpendicular to the posterior portions of the joint surface.

Figure 3

Sonogram of normal facet joints. The left sonogram shows the parasagittal plane of the normal facet joints. Notes: In the left sonogram, S indicates superior articular process, I indicates inferior articular process, and C indicates articular cartilage. The articular surface of the superior and inferior articular processes is smooth, arcuate, and high echoic. Articular cartilage is clear and low echoic, and is located between articular processes. Right sonogram shows the transverse section of the normal facet joints. Notes: In the right sonogram, J indicates spinous process of lumbar vertebrae and F indicates facet joint. There is a low-echoic fissure on the irregular, curved, and high-echoic stripe, which is articular cartilage.

Figure 4

CT image of normal facet joints. The left is the CT image of the parasagittal plane of the normal facet joints. The right is the CT image of the transverse section of the normal facet joints. Notes: S indicates superior articular process, I indicates inferior articular process, C indicates articular cartilage, J indicates spinous process of lumbar vertebrae, and F indicates facet joint. The articular surface of superior and inferior articular process is smooth, regular, and high-density. The low-density fissure between articular processes is articular cartilage.

Figure 5

Pictures of abnormal facet joint on the parasagittal plane. Notes: In the left sonogram, S indicates superior articular process, I indicates inferior articular process, and C indicates articular cartilage. The articular cartilage turns thinner obviously and joint space turns narrow. The right picture is the corresponding CT image.

Figure 6

Pictures of abnormal facet joint on the parasagittal plane. Notes: In the left sonogram, S indicates superior articular process, I indicates inferior articular process, and C indicates articular cartilage. The bone of the inferior articular process is destroyed, so the continuity of articular surface is broken. The right picture is the corresponding CT image.