Increased pelvic incidence may lead to arthritis and sagittal orientation of the facet joints at the lower lumbar spine

Abstract

BackgroundCorrect sagittal alignment with a balanced pelvis and spine is crucial in the management of spinal disorders. The pelvic incidence (PI) describes the sagittal pelvic alignment and is position-independent. It has barely been investigated on CT scans. Furthermore, no studies have focused on the association between PI and facet joint (FJ) arthritis and orientation. Therefore, our goal was to clarify the remaining issues about PI in regard to (1) physiologic values, (2) age, (3) gender, (4) lumbar lordosis (LL) and (5) FJ arthritis and orientation using CT scans.MethodsWe retrospectively analyzed CT scans of 620 individuals, with a mean age of 43 years, who presented to our traumatology department and underwent a whole body CT scan, between 2008 and 2010. The PI was determined on sagittal CT planes of the pelvis by measuring the angle between the hip axis to an orthogonal line originating at the center of the superior end plate axis of the first sacral vertebra. We also evaluated LL, FJ arthritis and orientation of the lumbar spine.Results596 individuals yielded results for (1) PI with a mean of 50.8°. There was no significant difference for PI and (2) age, nor (3) gender. PI was significantly and linearly correlated with (4) LL (p = < 0.0001). Interestingly, PI and (5) FJ arthritis displayed a significant and linear correlation (p = 0.0062) with a cut-off point at 50°. An increased PI was also significantly associated with more sagitally oriented FJs at L5/S1 (p = 0.01).ConclusionPI is not correlated with age nor gender. However, this is the first report showing that PI is significantly and linearly associated with LL, FJ arthritis and more sagittal FJ orientation at the lower lumbar spine. This may be caused by a higher contact force on the lower lumbar FJs by an increased PI. Once symptomatic or in the event of spinal trauma, patients with increased PI and LL could benefit from corrective surgery and spondylodesis.

Characterisation of the correlation between standing lordosis and degenerative joint disease in the lower lumbar spine in women and men: a radiographic study

“…For instance, the female lumbar spine is morphologically suited to increased lordosis [ 33 ], and in young women decreased lumbar lordosis correlates with disc degeneration [ 34 ]. This has also been recently shown in men [ 20 ]. Similarly, Increased or prolonged loading of the intervertebral disc is thought to contribute to its degeneration through compromising its nutrient supply [ 35 – 37 ].…”

“…It has long been known that decreased lordosis increases the load on the intervertebral discs and increased lordosis increases the load on the facet joints [ 9 , 10 ]. More importantly, it is known that increased pelvic incidence (PI), which increases lumbar lordosis, correlates with DJD of the facet joints [ 20 – 22 ], which in turn is associated with low back pain [ 23 ]. Increased PI is also associated with wedging of intervertebral discs, spondylolysis and spondylolisthesis [ 24 ].…”

Spinopelvic alignment predicts disc calcification, displacement, and Modic changes: Evidence of an evolutionary etiology for clinically‐relevant spinal phenotypes

“…PI is generally thought to be unaffected by lumbar degenerative changes . Association of increased PI with spondylolisthesis and facet joint degeneration has been reported by several studies. Previously, a decreased PI was noted with degenerative disc disease, lumbar disc displacement, and chronic LBP .…”

“…Balanced sagittal alignment of the spine is vital for spinal function and is crucial to maintain upright postures . The neutral upright sagittal alignment is achieved only when the spine and pelvis are in sync . The harmonious connection of the pelvis with the spine, also known as “spinopelvic balance,” contributes considerably to overall sagittal balance.…”

“…14,15 The neutral upright sagittal alignment is achieved only when the spine and pelvis are in sync. 16,17 The harmonious connection of the pelvis with the spine, also known as "spinopelvic balance," contributes considerably to overall sagittal balance. The three main defining spinopelvic parameters are pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) (Figure 1).…”