Although asymptomatic adults stood with stable global balance, the sagittal spinal alignment of healthy subjects, newly divided in 5 sagittal types, varied significantly. Type 3 AP appears as a new and unusual sagittal shape with low-grade PI, very low or negative PT, and hyperlordosis. Whereas most asymptomatic adults stood with C7PL behind the hip axis, a sizeable portion had C7 in front of the hip axis. This could be a new controversial aspect of ideal spinal balance.

Level IV.

It seems that keeping the physiological morphology is the treatment of choice. For patients with degenerative scoliosis, reducing the kyphosis could work. We do not recommend to increase the lordosis and obtain a type 3 morphology with an anteverted pelvis because of the risk of PJK and poor functional results.

Level IV (e.g. case series).

Study Design: Retrospective cross-sectional study. Objective: The aim was to describe existing global sagittal alignment parameters across ages and to analyze differences according to gender and pelvic incidence (PI). Summary of Background Data: Variability with age has been reported. It remains unclear how gender and spinopelvic morphology could additionally influence global alignment parameters. Materials and Methods: Radiographs of 2599 individuals (5–93 y) were analyzed. Translation parameters were: Sagittal Vertical Axis (SVA)-C7, SVA-C2, SVA-Center Acoustic Meatus (CAM), C7/Sacrofemoral Distance (SFD) ratio. Inclination parameters were: C7-Vertical Tilt (VT), T1-VT and T9-VT, Odontoid-Hip Axis (OD-HA), OD-CAM. Pelvic compensation parameters were: T1-Pelvic Angle (TPA), Global Tilt (GT), Spino-Sacral Angle (SSA). Global sagittal alignment (GSA) was considered among formulae. The distribution of parameters was analyzed using a Bayesian inference. Correlations with spinopelvic parameters were investigated. Results: SVA-C7, SVA-C2, SVA-CAM were larger in males and high PI, and increased significantly after 50 years (Pr>0.9999). C7/SFD decreased during growth and was larger in low PI (Pr=0.951). There was no correlation with spinopelvic parameters. Age-related variations of inclination parameters were nonsignificant. T1-VT and T9-VT increased with PI and were significantly larger in high PI (Pr>0.95). C7-VT was significantly larger in low PI (Pr>0.9999). OD-HA and OD-CAM were constant and increased after 80 years. TPA and GT increased with PI (Pr>0.9999) and age after 35 years (Pr>0.9999). SSA decreased nonsignificantly after 50 years. TPA correlated with PI (ρ=0.6130) and pelvic tilt (PT) (ρ=0.8375). GT correlated with PI (ρ=0.5961) and PT (ρ=0.8996). SSA correlated with sacral slope (ρ=0.9026). GSA was larger in high PI (Pr>0.9999) and increased after 35 years (Pr>0.9999). GSA correlated with PT (ρ=0.7732). Conclusion: Translation parameters increase with age, more prominently in males and high PI. Variations of inclination parameters are smaller. Pelvic compensation parameters and GSA increase with age and are closely related to PT and spinopelvic morphology. Level of Evidence: Level III.

This study underscores the influence of the type of sagittal curvature on the clinical results of LTDR, with type 4 patients showing inferior clinical results because of a higher rate of residual lower back pain. The indication in LTDR should be reconsidered for discogenic lower back pain in type 4 patients.

Study design Descriptive radiographic analysis of a prospective multi-center database. Objective This study aims to provide normative values of spinopelvic parameters and their correlations according to age and pelvic incidence (PI) of subjects without spinal deformity. Methods After Institutional Review Board (IRB) approval, 1540 full spine radiographs were analyzed. Subjects were divided into 3 groups of PI: low PI < 45°, intermediate PI 45–60°, high PI > 60°, and then stratified by age (20–34, 35–49, 50–64, > 65 Y.O). Pelvic and spinal parameters were measured. Statistical analysis between parameters was performed using Bayesian inference and correlation. Results Mean age was 53.5 years (845 females, 695 males, range 20–93 years). In low PI group, lumbar lordosis (LL) decrease was mainly observed in the 2 younger age groups. In medium and high PI groups, loss of lordosis was linear during aging and occurred mainly on the distal arch of lordosis. Moderate PI group had a stable lordosis apex and thoracolumbar inflection point. High PI group had a stable thoracolumbar inflection point and a more distal lordosis apex in elderly subjects. For all subjects, kyphosis and pelvic tilt (PT) increased with age. There was a constant chain of correlation between PI and age groups. Proximal lumbar lordosis (PLL) was correlated with kyphosis and sagittal vertical axis (SVA C7), while the distal lumbar lordosis (DLL) was correlated with PI and PT. Conclusion This study provides a detailed repository of sagittal spinopelvic parameters normative values with detailed analysis of segmental kyphosis and lordosis distribution according to gender, age, and PI.

Learning targets• Posterior approach for vertebral body access