Changes in intervertebral sagittal alignment of the cervical spine from supine to upright

Abstract

Cervical sagittal alignment is a critical component of successful surgical outcomes. Unrecognized differences in intervertebral alignment between supine and upright positions may affect clinical outcomes; however, these differences have not been quantified. Sixty-four patients scheduled to undergo one or two-level cervical arthrodesis for symptomatic pathology from C4-C5 to C6-C7, and forty-seven controls were recruited. Upright sagittal alignment was obtained through biplane radiographic imaging and measured using a validated process with accuracy better than 1°in rotation. Supine alignment was obtained from computed tomography scans. Coordinate systems used to measure supine and upright alignment were identical. Distances between adjacent bony endplates were measured to calculate disc height in each position. For both patients and controls, the C1-C2, C2-C3, and C3-C4 motion segments were in more lordosis when upright as compared with supine (all p < 0.001). However, the C4-C5, C5-C6, and C6-C7 motion segments were in less lordosis when upright as compared with supine (all p ≤ 0.004). There was an interaction between group and position at the C1-C2 (p = 0.002) and C2-C3 (p = 0.001) motion segments, with the controls demonstrating a greater increase in lordosis at both motion segments when moving from supine to upright. The results indicate that cervical motion segment alignment changes between supine and upright positioning, those changes differ among motion segments, and cervical pathology affects the magnitude of these changes. Clinical Significance:Surgeons should be mindful of the differences in alignment between supine and upright imaging and the implications they may have on clinical outcomes.

Targeting GDF15 as a potential therapy for low back pain originating from endplate

“…Previous study showed that, the size of Modic changes and defects of cartilaginous and bony endplate were also strongly related with LBP [10][11][12] . The endplates changed into porous during intervertebral disk degeneration.…”

“…The center of the vertebral endplate is still covered by a thin layer of hyaline cartilage, which is the cartilage endplate 8,9 . In clinical MRI examination, the size of Modic changes and defects of cartilaginous and bony endplate are also strongly related with LBP [10][11][12] . It's reported that, endplates change into porous during intervertebral disk degeneration.…”

In vivo cervical vertebrae kinematic studies based on dual fluoroscopic imaging system measurement: A narrative review

“…Moderate-range joint motion tasks are more favorable than full-range motion tasks for assessing postoperative joint kinematic changes. Post ACDF surgery subjects,50 (29 M, 21F), 48.4 ± 7.6 One level (C5–C6) surgery subject, 19 (8 M, 11F) Two level (C5–C6–C7) surgery subjects, 19 (12 M, 8F) Two level (C4–C5–C6) surgery subjects, 11 (9 M, 2F) Oyekan et al, 2022 [ 40 ] Healthy subjects 47 (23 M, 24F), 35 ± 12 C1–C7 neutral position intervertebral disc height Cervical motion segment alignment changes between supine and upright positioning, those changes differ among motion segments, and cervical pathology affects these changes. Post C4–C5, C6–C7 ACDF surgery subjects 64 (32 M, 32F), 48 ± 8 Yeni.et al, 2022 [ 41 ] Post ACDF surgery subjects 8 (4 M, 4F), 42.5 ± 10.1 C3–C7 Axial rotation, Extension, ROM There is no increase in adjacent segment motion after fusion.…”

“…Various participant positioning (supine vs. sitting) [ 19 , 26 , 40 ], motion speed during data collection (potential differences in muscle forces applied to the vertebrae), initial head position at the start of motion, and variations in applied loads during motion [ 26 ] can all have varying degrees of impact on study results.…”