Pelvic thickness, sex, ethnicity, and age affect pelvic incidence in healthy volunteers of Multi-Ethnic Alignment Normative Study (MEANS) database

Characteristics of Spinal Morphology According to the "Current" and "Theoretical" Roussouly Classification Systems in a Diverse, Asymptomatic Cohort: Multi-Ethnic Alignment Normative Study (MEANS)

STUDY DESIGN

Cross-sectional cohort study.

OBJECTIVE

To classify spinal morphology using the "current" and "theoretical" Roussouly systems and assess sagittal alignment in an asymptomatic cohort.

METHODS

467 asymptomatic volunteers were recruited from 5 countries. Radiographic parameters were measured via the EOS imaging system. "Current" and "theoretical" Roussouly classification was assigned with sagittal whole spine imaging using sacral slope (SS), pelvic incidence (PI), and the lumbar apex. One-way analysis of variance (ANOVA) was performed to compare subject characteristics across Roussouly types, followed by post hoc Bonferroni correction.

RESULTS

Volunteers were categorized into 4 groups (Types 1-4) and 1 subgroup (Type 3 AP) using the "current" and "theoretical" Roussouly systems. The mean PI in "current" Roussouly groups was 40.8° (Type 1), 43.6° (Type 2), 52.4° (Type 3), 62.4° (Type 4), and 43.7° (Type 3AP). The mean PI in "theoretical" Roussouly groups was 36.5° (Type 1), 39.1°(Type 2), 52.5° (Type 3), 67.3° (Type 4), and 51.0° (Type 3AP). The difference in PI between "current" and "theoretical" Roussouly types was significant for Type 1 (P = .02), Type 2 (P < .001), Type 4 (P < .001), and Type 3AP (P < .001). 34.7% of subjects had a "current" Roussouly type different from the "theoretical" type. Type 3 theoretical shape had the most frequent mismatch, constituting 61.1% of the mismatched subjects. 51.5% of mismatched Type 3 become "current" Type 4.

CONCLUSION

The distribution of Roussouly types differs depending on whether the "current" or "theoretical" classification are employed. A sizeable proportion of volunteers exhibited current and theoretical type mismatch, highlighting the need to interpret sagittal alignment cautiously when utilizing the Roussouly system.

Associations between NCLBP, spinal sagittal alignment and age groups: a cross-sectional cohort study

PURPOSE

Nonspecific chronic low back pain (NCLBP) is one of the most common manifestations of degenerative spondylitis. It affects many patients of all ages and seriously interferes with quality of life. However, the associations between NCLBP, sagittal alignment and age remain unclear. We aimed to investigate the typical features of sagittal alignment in individuals with NCLBP and to discuss the relationships between age and these NCLBP-related changes in sagittal alignment.

METHODS

We measured the sagittal parameters of patients with NCLBP and investigated their sagittal alignment and compensatory mechanisms by comparing them with those of asymptomatic individuals.

RESULTS

A total of 905 elderly patients (≥ 50 years old) and 1296 young patients (< 50 years old) were included. An analysis of sagittal parameters revealed that elderly patients with NCLBP had a smaller lumbar lordosis (LL, p = 0.001) and a greater T1 pelvic angle (TPA, p < 0.001). Age was significantly correlated with the TPA (rs = 0.549, p < 0.001) and pelvic tilt (PT, rs = 0.471, p < 0.001). The AUC value of the TPA was 0.782 (95% CI 0.764 to 0.799).

CONCLUSIONS

Although decreased lumbar lordosis is the most typical sagittal feature in patients with NCLBP, there are still differences in sagittal alignment between different ages. Compared with young patients, elderly patients with NCLBP more commonly present with a decompensated pattern of the anterior inclination of the trunk as the main sagittal alignment abnormality. TPA is more predictive than LL for the diagnosis of geriatric NCLBP.

Sacrum1-pubic angle: a novel and alternative morphologic radiological parameter for assessing spinopelvic sagittal alignment in human adults

OBJECTIVE

Spinopelvic sagittal balance ensures efficient posture and minimizes energy expenditure by aligning the spine, pelvis, and lower extremities. Deviations can cause clinical issues like back pain and functional limitations. Key radiographic parameters, including pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), and lumbar lordosis (LL), are essential for evaluating spinal pathologies and planning surgeries. Accurate PI measurement is challenging in certain conditions, necessitating alternative parameters. This study aimed to introduce a new, easily measurable parameter and examine its reliability and correlation with established sagittal parameters.

METHODS

This study analyzed 107 asymptomatic adult volunteers (57 males and 50 females), with an average age of 36.75 years. Whole-spine radiographs in the standing position were taken using EOS technology. The established spinopelvic sagittal parameters and a novel parameter, sacrum1-pubic angle (S1PA), were measured. The correlation coefficient of each parameter, the regression equation of PI using S1PA, and the regression equation of PTα using PTβ were obtained. The intraclass correlation coefficients (ICCs) was calculated to evaluate the measurement reliability.

RESULTS

Morphologic (S1PA, PI) and positional parameters (PTα, PTβ, PTγ, SS, LL) showed no significant gender differences (p > 0.05). S1PA had strong correlations with PI (r = -0.883, p < 0.001) and other parameters. PTα demonstrated a strong correlation with PTβ (r = -0.929, p < 0.001). PI could be predicted according to the regression equation: PI = 71.672 - 4.537 × S1PA (R² = 0.779, p < 0.001). The PTα could be predicted using the following equation: PTα = 67.245 - 0.865 × PTβ (R² = 0.864, p < 0.001). Reliability analysis showed high intra- and inter-rater agreement in all the spinopelvic parameters.

CONCLUSION

The S1PA is a dependable parameter for evaluating the morphology and orientation of the pelvis. PI could be precisely predicted using the S1PA. These insights are valuable for clinicians, enhancing their ability to assess spinopelvic sagittal alignment accurately.

The effect of degenerative scolioisis on segmental thoracolumbar sagittal alignment compared to age- and pelvic incidence-matched reference values

INTRODUCTION

In asymptomatic subjects, variations of sagittal alignment parameters according to age and pelvic incidence (PI) has been reported. The aim of this observational study was to describe thoraco-lumbar sagittal alignment in patients with degenerative scoliosis and to compare them to asymptomatic individuals, seeking for the specific effect of deformity in similar age and PI groups.

MATERIALS AND METHODS

Full spine radiographs of 235 asymptomatic subjects and 243 scoliosis patients were analyzed: cervico-thoracic inflexion point (CTIP), thoraco-lumbar inflexion point (TLIP), lumbar lordosis (LL) L1-S1, LL (TLIP-S1), LL superior arch (TLIP-lumbar apex), LL inferior arch (lumbar apex-S1), PI, thoracic kyphosis (TK) T5-T12, TK T1-T12, number of vertebrae CTIP-TLIPandTLIP-S1. The distribution of parameters was analyzed using a Bayesian inference (significant when Pr > 0.975 or Pr < 0.025). Comparisons between reference (R) and pathologic (P) groups were matched according to age (40-60 years; >60 years) and PI (< 45°; 45-60°; >60°).

RESULTS

LL L1-S1 was significantly lower in the P-group (Pr = 1.0), decreased with age (Pr > 0.99) and increased with PI (Pr < 0.001). In contrast, there was no significant decrease with age for LL (TLIP-S1) or LL (superior arch) (respectively Pr < 0.92 and Pr > 0.19). LL in the inferior arch was significantly lower in the P-group (Pr = 1.0) and decreased with age (Pr = 0.99). The number of vertebrae TLIP-S1 was significantly lower in the P-group compared to the reference group (Pr < 0.001).Thoracic kyphosis T1-T12 was significantly lower in the P-group (Pr < 0.001), without significant influence of age or PI. The number of vertebrae CTIP-TLIP increased significantly in the P-group (Pr < 0.001) and with PI (Pr < 0.004).

CONCLUSION

This observational study highlights specific thoraco-lumbar sagittal alignment adaptations in degenerative scoliosis, matched on age and PI. Beyond the decrease in LL due to aging, degenerative scoliosis leads to a distal migration of the TLIP, an increase in the number of vertebrae in TK and a decrease in LL. This phenomenon was linked to kyphosis at the thoraco-lumbar junction due to scoliosis and was more important in high PI.

Does global spinal alignment affect the use of walking aids after multi-segment spinal fixation for patients with ASD? A multicenter retrospective study

PURPOSE

This study aimed to clarify the relation between global spinal alignment and the necessity of walking aid use in patients with adult spinal deformity (ASD) and to investigate the impact of spinal fixation on mobility status after surgery.

METHODS

In total, 456 older patients with ASD who had multi-segment spinal fixation surgery and were registered in a multi-center database were investigated. Patients under 60 years of age and those unable to walk preoperatively were excluded. Patients were classified by their mobility status into the independent, cane, and walker groups. Comparison analysis was conducted using radiographic spinopelvic parameters and the previously reported global spine balance (GSB) classification. In addition, preoperative and 2 years postoperative mobility statuses were investigated.

RESULTS

Of 261 patients analyzed, 66 used walking aids (canes, 46; walkers, 20). Analysis of preoperative radiographical parameters showed increased pelvic incidence and pelvic incidence-lumbar lordosis mismatch in the walker group and increased sagittal vertebral axis in the cane and walker groups versus the independent group. Analysis of GSB classification showed a higher percentage of walker use in those with severe imbalance (grade 3) in the sagittal classification but not in the coronal classification. While postoperative radiographical improvements were noted, there was no significant difference in the use of walking aids before and 2 years after surgery (P = 0.085).

CONCLUSION

A significant correlation was found between "sagittal" spinal imbalance and increased reliance on walking aids, particularly walkers. However, the limitation of improvement in postoperative mobility status suggested that multiple factors influence the mobility ability of elderly patients with ASD.

Analysis of spinopelvic parameters in adult patients with lumbosacral transitional vertebrae

PURPOSE

Spinopelvic sagittal alignment is crucial for assessing balance and determining treatment efficacy in patients with adult spinal deformity (ASD). Only a limited number of reports have addressed spinopelvic parameters and lumbosacral transitional vertebrae (LSTV). Our primary objective was to study spinopelvic sagittal parameter changes in patients with LSTV. A secondary objective was to investigate clinical symptoms and quality of life (QOL) in patients with LSTV.

METHODS

In this study, we investigated 371 participants who had undergone medical check-ups for the spine. LSTV was evaluated using Castellvi's classification, and patients were divided into LSTV+ (type II-IV, L5 vertebra articulated or fused with the sacrum) and LSTV- groups. After propensity score matching for demographic data, we analyzed spinopelvic parameters, sacroiliac joint degeneration, clinical symptoms, and QOL for these two participant groups. Oswestry Disability Index (ODI) scores and EQ-5D (EuroQol 5 dimensions) indices were compared between the two groups.

RESULTS

Forty-four patients each were analyzed in the LSTV + and LSTV- groups. The LSTV + group had significantly greater pelvic incidence (52.1 ± 11.2 vs. 47.8 ± 10.0 degrees, P = 0.031) and shorter pelvic thickness (10.2 ± 0.9 vs. 10.7 ± 0.8 cm, P = 0.018) compared to the LSTV- group. The "Sitting" domain of ODI (1.1 ± 0.9 vs. 0.6 ± 0.7, P = 0.011) and "Pain/Discomfort" domain of EQ-5D (2.0 ± 0.8 vs. 1.6 ± 0.7, P = 0.005) were larger in the LSTV + group.

CONCLUSION

There was a robust association between LSTV and pelvic sagittal parameters. Clinical symptoms also differed between the two groups in some domains. Surgeons should be aware of the relationship between LSTV assessment, radiographic parameters and clinical symptoms.

LEVEL OF EVIDENCE: 3

Association between posterior tibial slope and anatomic spinopelvic parameters: a retrospective cross-sectional study

PURPOSE

Only a few publications considered the influence of the spinopelvic parameters on below-hip anatomy. There is a lack of evidence about the relationship between the anatomic spinopelvic parameters and the posterior tibial slope (PTS). Therefore, the aim of this study was to analyze the association between fixed anatomic spinopelvic parameters and PTS.

METHODS

Adult patients presenting with lumbar, thoracic, or cervical complaints together with knee pain at a single hospital between 2017 to 2022 with available standing full-spine lateral radiograph and lateral knee radiograph were retrospectively reviewed. The measured parameters included the pelvic incidence (PI), the sacral kyphosis (SK), the pelvisacral angle, the sacral anatomic orientation (SAO), the sacral table angle, the sacropelvic angle and the PTS. Pearson's correlations and linear regression analyses were conducted.

RESULTS

A total of 80 patients (44 women), median age 63 years were analyzed. A strong positive correlation was identified between PI and PTS (r = 0.70, p < 0.001). A strong negative correlation was observed between PI and SAO (r = - 0.74, p < 0.001). A strong positive correlation was observed between PI and SK (r = 0.81, p < 0.001). A univariable linear regression analysis showed that PTS can be deduced from PI according to the following formula: PTS = 0.174 × PI - 1.138.

CONCLUSION

This study is the first to support a positive correlation between the PI and the PTS. We demonstrate that knee anatomy is individually correlated to pelvic shape and therefore influences spinal posture.

Scoliosis Research Society-22r score is affected by standing whole body sagittal alignment, age, and sex, but not by standing balance or skeletal muscle mass in healthy volunteers

PURPOSE

Aging and spinal disease impair standing whole body sagittal alignment (WBS alignment), which leads to stooping. When WBS alignment deteriorates, compensatory mechanisms are activated to maintain standing posture. Increase of the compensation impairs health-related quality of life (HRQOL). The purpose of this research was to determine whether postural factors, age, and sex affect HRQOL.

METHODS

This cross-sectional study evaluated the influence of WBS alignment, standing body sway (balance), skeletal muscle mass (SMM), aging, and sex on HRQOL in healthy volunteers (n = 150; mean age 40.9 years [20-76], 96 women). Age, sex, weight, height, and body mass index (BMI) were obtained. HRQOL was assessed with Scoliosis Research Society-22 (SRS-22r). WBS alignment and balance were measured by EOS imaging with simultaneous force plate measurement. SMM was measured using a medical body composition analyzer. Based on the bivariate analysis between the SRS-22r subtotal and all parameters, selected ten parameters were used for multivariate logistic regression analysis to identify affecting factors to SRS-22r.

RESULTS

Men had significantly higher weight, height, BMI, and SRS-22r score in all domains. The L4-S1 lumbar lordosis angle was greater in men, and pelvic tilt and knee hyperextension were greater in women. Women had a more stable standing posture, whereas men had significantly higher SMM values. Multivariate logistic regression analysis revealed that age, sex, and TPA were identified as significant factors affecting SRS-22r.

CONCLUSIONS

In healthy volunteers, SRS-22r is affected by aging, sex (woman had a lower score), and sagittal malalignment. Neither Standing balance nor SMM, however, affect SRS-22r.4.