The Correlation Between Facet Tropism and Intervertebral Disc Herniation in the Subaxial Cervical Spine

Abstract

Study Design. A retrospective case–control study. Objective. Investigating the correlation between the facet tropism (FT) and subaxial cervical disc herniation (CDH). Summary of Background Data. Although debatable, it was widely reported that FT was associated with lumbar disc herniation. However, the exact correlation between FT and subaxial CDH is still unclear. Methods. Two-hundred patients with any disc herniation at C3/4, C4/5, C5/6, or C6/7 and 50 normal participants without CDH (normal control group) were included in this study. For patients, the cervical levels with CDH and the levels without herniation were classified into the “herniation group” and “patient control group,” respectively. Bilateral facet joint angles at C3/4, C4/5, C5/6, and C6/7 on sagittal, axial, and coronal planes were measured on computed tomography (CT). The disc degeneration at each level was assessed on magnetic resonance imaging (MRI). Results. Both the mean difference between left and right facet angles and tropism incidence in herniation group were significantly greater than those in two control groups whenever at C3/4, C4/5, C5/6, or C6/7 level and whenever on sagittal, axial, or coronal plane. The mean differences of angles and tropism incidences in most patient control groups were not significantly greater than those of corresponding normal control groups. The incidence of greater facet angle at the left or right side was not significantly different among the left, central, and right herniation groups. The mean disc degeneration grades in both herniation and patient control groups were significantly higher than those in normal control groups while no difference between herniation and patient control groups. Conclusion. The FT on the sagittal, axial, and coronal planes are all associated with CDH in the subaxial cervical spine. The greater facet angle at the left or right side does not affect the side of herniation. The severity of cervical disc degeneration is not associated with FT. Level of Evidence: 3

Tropism of Sub-Axial Cervical Facet Joints Is Not Related to Segmental Movement during Active Movement or Therapist-Perceived Symptomatic Locations

“…There are conflicting views on the relevance of spinal tropism-in particular, whether tropism in the spine is related to degenerative changes of the facets or discs. A recent systematic review with meta-analysis [6] found that there is a relationship between tropism and degenerative changes for both the lumbar and cervical spines, and a further study in the cervical spine reinforced these findings [7]. Such changes are paradoxically thought to result from tropism either limiting movement [8] or increasing instability [9], but in either case, the result is thought to be increased stresses on the facets and discs [10].…”

A Systematic Review and Meta-Analysis of the Facet Joint Orientation and Its Effect on the Lumbar

“…The facet tropism is interpreted as the asymmetry between the left and the right angles of the facet joints, along with one joint, which has a more sagittal positioning than the other. This was intended to enhance risks for the degradative disorder in the equivalent disc herniation and the rotational variability of the spinal segment [ 7 ]. The degenerative spondylolisthesis is recognized as a lumbar vertebral body sliding ahead of the adjoining vertebral body without the neural arch flaw because of the variable effect of the progressive variation.…”

Are Facet Orientation and Tropism Risk Factors for Cervical Spondylotic Radiculopathy? A Retrospective Study in a Chinese Population

“…Finally, the side of disc herniation was associated with the side of larger axial FO, meaning that the direction of herniation preferred the side of greater FO. It has been demonstrated in a previous cervical study that the greater facet angle at the left or right side did not affect the side of herniation in patients with cervical disc herniation [25]. This could be explained by the different experimental design, study population and methodology.…”

“…A rat model study reported that participating factors to disc herniation were not only axial compression but exion and torsion [39]. It is commonly held that cervical facet joints are 3-dimentional, including that axial cervical spine is responsible for rotation movement, sagittal cervical spine is responsible for exion-extension, and coronal cervical spine is responsible for lateral bending [24,25]. Previous biomechanical ndings proposed that the biomechanical effects of FT rather than FO contributed to the increases in disc stress and facet joint contact at the corresponding segment [32,40].…”

“…1a, b), axial FO (α) was de ned as the angle between facet line and midsagittal line which was draw perpendicular to the posterior wall of vertebral body, using the measurement method of lumbar FO described by Noren et al [12]; on sagittal view (Fig. 1c, d), sagittal FO (β) was de ned as the angle between the superior facet line and a line perpendicular to the posterior wall of inferior vertebral body described by Sebastien et al [24], it was worth noting that this measurement method of sagittal FO is not in uenced by head position and cervical curvature, and more accurate thanks to more straighter line of superior facet than inferior one, compared with other method [25]; on coronal view (Fig. 1e, Measurement data conformed to the normal distribution were expressed as the mean ± standard deviation, while results conformed to abnormal distribution were expressed as median [P 25 , P 75 ].…”