Predictive model of global tilt (GT) determined by individual thoracic kyphosis, lumbar lordosis and pelvic incidence in the human degenerative spine

Global tilt angle in spinal alignment of asymptomatic older women with low bone mass

This study investigated the relationship between sagittal spinal alignment and musculoskeletal health in older women, particularly those exhibiting diminished bone density without apparent symptoms. The study assessed the impact of global tilt (GT) and the presence of coronal malalignment on spinal health. The research involved 165 asymptomatic older women with an average age of 68.91 ± 7.25 years and average body mass index of 24.26 ± 3.66 kg/m². Comprehensive standing anteroposterior and lateral spine radiographs were used for assessment. Through multivariate linear regression analysis, the study identified significant correlations between increased GT angles and various factors, including coronal malalignment, the C7 slope, and pelvic incidence. This led to the formulation of a predictive GT model: GT = -9.79 + 0.06 × menopausal period + 0.19 × body mass index (BMI)- 0.81 × average T score - 0.11 × grip strength + 3.03 × (presence of coronal malalignment) + 0.08 × sagittal vertical axis (SVA) + 0.12 × C7 slope - 0.35 × upper lumbar lordosis (ULL) - 0.43 × lower lumbar lordosis (LLL) + 0.70 × pelvic incidence (PI), with an adjusted R² of 0.816. The study findings highlight the prevalence of coronal malalignment in this demographic and its significant associations with critical spinal parameters. The proposed GT predictive model may enable development of personalized treatment plans for older women with low bone mass.

Research of Global Tilt and Functional Independence: Insights into Spinal Health of Older Women

Spinal alignment intricately influences functional independence, particularly in older women with osteopenia experiencing mild neck and back pain. This study elucidates the interplay between spinal alignment, bone mineral density (BMD), and muscle strength in elderly women presenting with mild neck and back pain. Focusing on a cohort of 189 older women, we examined the associations among global tilt (GT), coronal and sagittal alignment, BMD, grip strength, and functional independence as gauged by the Barthel index. Our findings indicate significant associations between functional capacity and grip strength, bone density, GT, and pelvic tilt (PT). Elderly women with a Barthel Index above 80 demonstrated higher grip strength and better bone quality, reflected by less negative average T scores. These individuals also exhibited lower values of GT and PT, suggesting a better sagittal alignment compared to those with a Barthel index of 80 or below. The results highlight that deviations in GT and PT are significantly associated with decreased functional independence. These insights emphasize the importance of maintaining optimal spinal alignment and muscle strength to support functional independence in elderly women. This study underscores the potential for targeted interventions that improve postural stability and manage pain effectively in this vulnerable population.

Predicting thoracic kyphosis morphology and the thoracolumbar inflection point determined by individual lumbar lordosis in asymptomatic adults

PURPOSE

The aims of this study were to explore the correlations between thoracic kyphosis (TK) and lumbar lordosis (LL) parameters and to build corresponding linear regressions to predict TK morphology and the thoracolumbar inflection point (IP) determined by individual LL parameters in asymptomatic adults.

METHODS

A total of 280 adult healthy volunteers were recruited, and full-spine X-rays were performed for each subject in a standing posture. The following sagittal parameters were measured: cumulative TK, LL, proximal LL (PLL), the apices of TK (TKA) and LL (LLA), the IP and the distance from the plumb line of the thoracic apex (TAPL) and the lumbar apex (LAPL) to the gravity line. The correlations between TK and LL parameters were analyzed, and the corresponding linear regressions were conducted.

RESULTS

Extensive variations existed in TK alignment, including angular and morphological parameters. In addition, there were statistical correlations of all cumulative TK angles with LL (r values from - 0.173 to - 0.708) and PLL (r values from - 0.206 to - 0.803), TKA and IP with LLA (rs = 0.359 and 0.582, respectively) and TAPL with LAPL (rs = 0.335). The common predictive formulas employed in ASD surgery could include T10-L1 = - 3.6-0.2*LL (R2 = 0.201), T4-L1 = 3.4-0.5*LL (R2 = 0.457), TKA = - 10.3 + 1.1*LLA (R2 = 0.180) and IP = - 12.7 + 1.6*LLA (R2 = 0.330).

CONCLUSION

There were intimate associations between TK and LL parameters in asymptomatic adults. Moreover, predictive models for thoracic alignment, particularly cumulative TK, based on LL parameters were proposed, which could better delineate anatomical relationships, guide thoracic construction during adult spinal deformity surgery and may help preventing proximal junctional failure.

Relationships between lumbar lordosis correction and the change in global tilt (GT) in adult spinal deformity

PURPOSE

This study aimed to explore the relationships between lumbar lordosis (LL) correction and improvement of postoperative global sagittal alignment and to establish corresponding linear regressions to predict the change in global tilt (GT) based on the corrected LL following adult spinal deformity (ASD) surgery.

METHODS

A total of 240 ASD patients who underwent lumbar correction were enrolled in this multicentre study. The following sagittal parameters were measured pre- and postoperatively: thoracic kyphosis (TK), LL, upper and lower LL (ULL and LLL), pelvic tilt (PT), sagittal vertical axis (SVA) and GT. The correlations among the changes in GT (△GT), SVA (△SVA), PT (△PT), TK (△TK), LL (△LL), ULL (△ULL) and LLL (△LLL) were assessed, and linear regressions were conducted to predict △GT, △SVA, △PT and △TK from △LL, △ULL and △LLL.

RESULTS

△LL was statistically correlated with △GT (r = 0.798, P < 0.001), △SVA (r = 0.678, P < 0.001), △PT (r = 0.662, P < 0.001) and △TK (r = - 0.545, P < 0.001), and the outcomes of the linear regressions are: △GT = 3.18 + 0.69 × △LL (R2 = 0.636), △SVA = 4.78 + 2.57 × △LL (R2 = 0.459), △PT = 2.57 + 0.34 × △LL (R2 = 0.439), △TK = 7.06-0.43 × △LL (R2 = 0.297). In addition, △LLL had more correlations with △GT, △SVA and △PT, while △ULL had more correlations with △TK.

CONCLUSION

Surgical correction of LL could contribute to the restoration of global sagittal morphology following ASD surgery. These models were established to predict the changes in sagittal parameters, in particular △GT, determined by △LL, which has not been previously done and may help to customize a more precise correction plan for ASD patients.

Sagittal alignment cut-off values for predicting future fall-related fractures in community-dwelling osteoporotic women

PURPOSE

Determining the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures is essential for understanding fracture risk and informing clinicians and physical therapists. We determined the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures in this study.

METHODS

In the retrospective cohort study, we enrolled a total of 255 women aged ≥ 65 years who visited an outpatient osteoporosis clinic. We measured participants' bone mineral density and sagittal alignment, including sagittal vertical axis (SVA), pelvic tilt, thoracic kyphosis, pelvic incidence, lumbar lordosis, global tilt, and gap score at the initial visit. The cut-off value for sagittal alignment that was significantly associated with fall-related fractures was calculated after using multivariate Cox proportional hazards regression analysis.

RESULTS

Ultimately, 192 patients were included in the analysis. After a mean follow-up of 3.0 years, 12.0% (n = 23) had fractures due to falls. Multivariate Cox regression analysis confirmed that SVA (hazard ratio [HR] = 1.022, 95% confidence interval [CI] = 1.005-1.039) was the only independent predictor of fall-related fracture occurrence. The predictive ability of SVA for the occurrence of fall-related fractures was moderate (area under the curve [AUC] = 0.728, 95% CI = 0.623-0.834), with a cut-off value of 100 mm for SVA. SVA classified by cut-off value was also associated with an increased risk of developing fall-related fractures (HR = 17.002, 95% CI = 4.102-70.475).

CONCLUSION

We found that assessing the cut-off value of sagittal alignment would be useful information in understanding fracture risk in postmenopausal older women.

Sagittal alignment cut-off values for predicting future fall-related fractures in community-dwelling osteoporotic women

PURPOSE

Determining the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures is essential for understanding fracture risk and informing clinicians and physical therapists. We determined the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures in this study.

METHODS

In the retrospective cohort study, we enrolled a total of 255 women aged ≥ 65 years who visited an outpatient osteoporosis clinic. We measured participants' bone mineral density and sagittal alignment, including sagittal vertical axis (SVA), pelvic tilt, thoracic kyphosis, pelvic incidence, lumbar lordosis, global tilt, and gap score at the initial visit. The cut-off value for sagittal alignment that was significantly associated with fall-related fractures was calculated after using multivariate Cox proportional hazards regression analysis.

RESULTS

Ultimately, 192 patients were included in the analysis. After a mean follow-up of 3.0 years, 12.0% (n = 23) had fractures due to falls. Multivariate Cox regression analysis confirmed that SVA (hazard ratio [HR] = 1.022, 95% confidence interval [CI] = 1.005-1.039) was the only independent predictor of fall-related fracture occurrence. The predictive ability of SVA for the occurrence of fall-related fractures was moderate (area under the curve [AUC] = 0.728, 95% CI = 0.623-0.834), with a cut-off value of 100 mm for SVA. SVA classified by cut-off value was also associated with an increased risk of developing fall-related fractures (HR = 17.002, 95% CI = 4.102-70.475).

CONCLUSION

We found that assessing the cut-off value of sagittal alignment would be useful information in understanding fracture risk in postmenopausal older women.

A 5-year follow-up of the effect of corrective surgery in young adults with idiopathic scoliosis

PURPOSE

The purpose of this study was to determine mid-long-term outcomes (5 years) following surgery for young adult idiopathic scoliosis (YAdIS).

METHODS

This is a retrospective review of a prospective, multicenter adult deformity database including patients operated on idiopathic scoliosis by a single posterior approach, age at surgery between 19 and 29 (considered young adults), and 5-year follow-up. Demographic, radiographic and PROMS were analyzed preoperatively, at 2 years and at final follow-up.

RESULTS

Forty-two patients were included. Mean preoperative major curve angle was 59.65 ± 18.94. Main coronal curve initial correction was 56.38%, with 6% loss at 5 years. From baseline to 5 years after surgery, there was improvement in all PROMs (P < 0.004)-especially self-image-, except NRS-leg pain. This improvement was present at 6 months for all PROMs except for functional outcomes (SRS-Function and ODI) in which the improvement took place between 6 months and 2 years. In the 2- to 5-year follow-up period, no significant changes were seen in any PROMs. The percentage of patients reaching MCID from baseline at 5 years was: 75% for SRS-image, 45% for SRS-pain, 47.5% for SRS-function, 51.3% for SRS-mental, 42.5% for SRS-total and 15.4% for ODI. Patients reaching PASS at 5 years were: 88.1% for SRS-image, 81% for SRS-pain, 92.9% for SRS-function, 57.1% for SRS-mental, 88.1% for SRS-total, 92.7% for ODI and 69% for NRS pain. 11 minor and 4 major complications were identified.

CONCLUSION

YAdIS surgery resulted in an early and significant improvement in PROMs, especially for self-image, significantly reaching MCID and PASS thresholds. These results were maintained during long-term (5-year) follow-up.

Spinopelvic measurements of sagittal balance with deep learning: systematic review and critical evaluation

PURPOSE

To summarize and critically evaluate the existing studies for spinopelvic measurements of sagittal balance that are based on deep learning (DL).

METHODS

Three databases (PubMed, WoS and Scopus) were queried for records using keywords related to DL and measurement of sagittal balance. After screening the resulting 529 records that were augmented with specific web search, 34 studies published between 2017 and 2022 were included in the final review, and evaluated from the perspective of the observed sagittal spinopelvic parameters, properties of spine image datasets, applied DL methodology and resulting measurement performance.

RESULTS

Studies reported DL measurement of up to 18 different spinopelvic parameters, but the actual number depended on the image field of view. Image datasets were composed of lateral lumbar spine and whole spine X-rays, biplanar whole spine X-rays and lumbar spine magnetic resonance cross sections, and were increasing in size or enriched by augmentation techniques. Spinopelvic parameter measurement was approached either by landmark detection or structure segmentation, and U-Net was the most frequently applied DL architecture. The latest DL methods achieved excellent performance in terms of mean absolute error against reference manual measurements (~ 2° or ~ 1 mm).

CONCLUSION

Although the application of relatively complex DL architectures resulted in an improved measurement accuracy of sagittal spinopelvic parameters, future methods should focus on multi-institution and multi-observer analyses as well as uncertainty estimation and error handling implementations for integration into the clinical workflow. Further advances will enhance the predictive analytics of DL methods for spinopelvic parameter measurement.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.