Sagittal alignment of the spine: What do you need to know?

Automatic 3D pelvimetry framework in CT images and its validation

In the field of spinal pathology, sagittal balance of the spine is usually judged by the spatial structure and morphology of pelvis, which can be represented by pelvic parameters. Pelvic parameters, including pelvic incidence, pelvic tilt and sacral slope, are therefore essential for the diagnosis and treatment of spinal disorders, however, it is a time-consuming and laborious procedure to measure these parameters by traditional methods. In this paper, an automatic measurement framework for pelvic CT images was proposed to calculate three-dimensional (3D) pelvic parameters with the support of deep learning technology. Pelvic images were first preprocessed, and 3D reconstruction was then performed to obtain 3D pelvic model by the Visualization Toolkit. DRINet was trained to segment the femoral head region in the pelvic images, and 3D sphere fitting was performed to locate the femoral heads. In addition, VGG16 was adopted to recognize images containing superior sacral endplate, and the plane growth algorithm was used to fit the plane so that the midpoint and normal vector of the superior sacral endplate could be obtained. Finally, 3D pelvic parameters were automatically calculated, and compared with manual measurements for 15 patients. The proposed framework automatically generated 3D pelvic models, and calculated two-dimensional (2D) and 3D pelvic parameters from continuous CT images. Experiments demonstrated that the framework can greatly speed up the calculation of pelvic parameters, and these parameters are accurate when compared with the manual measurements. In conclusion, the proposed framework demonstrates good performance on automatic pelvimetry measurement by incorporating deep learning technology, and can well replace the traditional methods for pelvic parameter measurement.

Analysis of the reliability of KEOPS version 2 for the measurement of coronal and sagittal parameters in spinal deformity

BACKGROUND

The purpose of the study is to evaluate the updated version of this software in patients with various spinal deformity.

METHODS

Sixty patients were included in this study and were divided into three categories: 20 patients with AIS, 20 patients with ASD, and 20 patients having undergone corrective surgery for spinal deformity. The measurements were performed by two senior and two junior orthopedic surgery residents, and were done at two points in time separated by a 3-week interval with the cases being randomized every time to reduce the risk of memory bias. Measured parameters included coronal, sagittal, global alignment parameters, and pelvic parameters.

RESULTS

When assessing the inter- and intra-observer reliability across all the groups of patients, none of the coefficients was smaller than 0.8 with a very high level of agreement. The standard error ranged from 0.7° to 1.5° demonstrating a high level of accuracy. Fairly similar results were seen when the groups were divided into the three categories except for the post-operative groups where a strong and not perfect level of agreement was reported.

CONCLUSION

This is the first study to assess the reproducibility of the new version of KEOPS, showing a very high agreement in all measurements. In the post-operative group, although it showed a strong agreement, the lower performance can be explained by the presence of surgical material making it harder to identify the anatomical landmarks accurately. Nevertheless, we can recommend the usage of this software in a clinical setting.

Reliability of the Biomechanical Assessment of the Sagittal Lumbar Spine and Pelvis on Radiographs Used in Clinical Practice: A Systematic Review of the Literature

Background: Biomechanical analysis of the sagittal alignment of the lumbar spine and pelvis on radiographs is common in clinical practices including chiropractic, physical therapy, scoliosis-related thoraco-lumbo-sacral orthosis (TLSO) management, orthopedics, and neurosurgery. Of specific interest is the assessment of pelvic morphology and the relationship between angle of pelvic incidence, sacral slope, and lumbar lordosis to pain, disability, and clinical treatment of spine conditions. The current state of the literature on the reliability of common methods quantifying these parameters on radiographs is limited. Methods: The objective of this systematic review is to identify and review the available studies on the reliability of different methods of biomechanical analysis of sagittal lumbo-pelvic parameters used in clinical practice. Our review followed the recommendations of the preferred reporting items for systematic reviews and meta-analyses (PRISMA). The design of this systematic review was registered with PROSPERO (CRD42023379873). Results: The search strategy yielded a total of 2387 articles. A total of 1539 articles were screened after deduplication and exclusion by automation tools, leaving 473 full-text articles that were retrieved. After exclusion, 64 articles met the inclusion criteria. The preponderance of the evidence showed good to excellent reliability for biomechanical assessment of sagittal lumbo-pelvic spine alignment. Conclusions: The results of this systematic review of the literature show that sagittal radiographic analysis of spinal biomechanics and alignment of the human lumbo-pelvic spine is a reliable tool for aiding diagnosis and management in clinical settings.

Artificial intelligence automatic measurement technology of lumbosacral radiographic parameters

Background

Currently, manual measurement of lumbosacral radiological parameters is time-consuming and laborious, and inevitably produces considerable variability. This study aimed to develop and evaluate a deep learning-based model for automatically measuring lumbosacral radiographic parameters on lateral lumbar radiographs.

Methods

We retrospectively collected 1,240 lateral lumbar radiographs to train the model. The included images were randomly divided into training, validation, and test sets in a ratio of approximately 8:1:1 for model training, fine-tuning, and performance evaluation, respectively. The parameters measured in this study were lumbar lordosis (LL), sacral horizontal angle (SHA), intervertebral space angle (ISA) at L4-L5 and L5-S1 segments, and the percentage of lumbar spondylolisthesis (PLS) at L4-L5 and L5-S1 segments. The model identified key points using image segmentation results and calculated measurements. The average results of key points annotated by the three spine surgeons were used as the reference standard. The model's performance was evaluated using the percentage of correct key points (PCK), intra-class correlation coefficient (ICC), Pearson correlation coefficient (r), mean absolute error (MAE), root mean square error (RMSE), and box plots.

Results

The model's mean differences from the reference standard for LL, SHA, ISA (L4-L5), ISA (L5-S1), PLS (L4-L5), and PLS (L5-S1) were 1.69°, 1.36°, 1.55°, 1.90°, 1.60%, and 2.43%, respectively. When compared with the reference standard, the measurements of the model had better correlation and consistency (LL, SHA, and ISA: ICC = 0.91-0.97, r = 0.91-0.96, MAE = 1.89-2.47, RMSE = 2.32-3.12; PLS: ICC = 0.90-0.92, r = 0.90-0.91, MAE = 1.95-2.93, RMSE = 2.52-3.70), and the differences between them were not statistically significant (p > 0.05).

Conclusion

The model developed in this study could correctly identify key vertebral points on lateral lumbar radiographs and automatically calculate lumbosacral radiographic parameters. The measurement results of the model had good consistency and reliability compared to manual measurements. With additional training and optimization, this technology holds promise for future measurements in clinical practice and analysis of large datasets.

Comprehensive assessment of global spinal sagittal alignment and related normal spinal loads in a healthy population

Abnormal postoperative global sagittal alignment (GSA) is associated with an increased risk of mechanical complications after spinal surgery. Typical assessment of sagittal alignment relies on a few selected measures, disregarding global complexity and variability of the sagittal curvature. The normative range of spinal loads associated with GSA has not yet been considered in clinical evaluation. The study objectives were to develop a new GSA assessment method that holistically describes the inherent relationships within GSA and to estimate the related spinal loads. Vertebral endplates were annotated on radiographs of 85 non-pathological subjects. A Principal Component Analysis (PCA) was performed to derive a Statistical Shape Model (SSM). Associations between identified GSA variability modes and conventional alignment measures were assessed. Simulations of respective Shape Modes (SMs) were performed using an established musculoskeletal AnyBody model to estimate normal variation in cervico-thoraco-lumbar loads. The first six principal components explained 97.96% of GSA variance. The SSM provides the normative range of GSA and a visual representation of the main variability modes. Normal variation relative to the population mean in identified alignment features was found to influence spinal loads, e.g. the lower bound of the second shape mode (SM2-2σ) corresponds to an increase in L4L5-compression by 378.64 N (67.86%). Six unique alignment features were sufficient to describe GSA almost entirely, demonstrating the value of the proposed method for an objective and comprehensive analysis of GSA. The influence of these features on spinal loads provides a normative biomechanical reference, eventually guiding surgical planning of deformity correction in the future.

Thoracolumbar Fractures: Comparing the Effect of Minimally Invasive Versus Open Schanz Screw Techniques on Sagittal Alignment

STUDY DESIGN

This is a retrospective comparative cohort study.

PURPOSE

This study aims to compare the effects of minimally invasive surgery (MIS) and open surgery (OS) on global sagittal alignment (GSA) in surgically managed thoracolumbar fractures.

OVERVIEW OF LITERATURE

The optimal treatment of traumatic thoracolumbar fractures (TLF) remains controversial. Both MIS techniques with polyaxial screws and OS techniques with Schanz screws have gained widespread use. The effect of each technique on the global sagittal alignment has not been reported.

METHODS

From 2014 to 2021, 22 patients with traumatic TLF underwent open posterior stabilization using an open transpedicular Schanz screw-rod construct and were compared to 15 patients who underwent minimally invasive surgery using a polyaxial percutaneous pedicle screw-rod construct. The reported radiological parameters measured on preoperative supine CT scan and immediate postop standing X-ray and on final follow-up whole spine standing X-rays included pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), preoperative segmental kyphosis (Preop-K), immediate post-operative segmental kyphosis (postop-Ki), final post-operative segmental kyphosis (postop-Kf), sagittal-vertica-axis (SVA), and spino-sacral angle (SSA).

RESULTS

The average age of the OS group was 42.5 years; 5 patients had AO type B, and 17 patients had AO type A (A3 and A4) fractures. The average follow-up was 16.8 months. The average radiological parameters were: PI = 54.9°, PI-LL = 3°, PT = 17.6°, preop-K = 16.2°, postop-Ki = 8.7°, final postop-Kf = 14.3°, SVA = 4.58 cm, and SSA = 101.8°. The average age of the MIS group was 43.4 years; 5 patients had AO type B, and 10 patients had AO type A fractures. The average follow-up was 25 months. The average radiological parameters were as follows: PI = 51°, PI-LL = 8°, PT = 18°, preop-K = 18.4°, postop-Ki = 11.6°, postop-Kf = 14.3°, SVA = 6.4 cm, SSA = 106°.

CONCLUSION

The fixation technique did not significantly affect the final correction of the local kyphosis and global spine alignment parameters.

Prevalence of spinal deformity development after surgical management of a congenital heart disease among children: a systematic review and meta-analysis

INTRODUCTION

Open heart surgery is the most common treatment for congenital heart disease. Thoracotomy, sternotomy, or a combination of both are the main approaches used in open heart surgeries. In cardiac surgery, there have been concerns that these surgeries increase the likelihood of spinal deformities. Therefore, this systematic review and meta-analysis provided updated evidence on the prevalence of spinal deformities following congenital heart surgery.

METHOD

EMBASE, Medline, ScienceDirect, and Google Scholar were used to search for studies published until 2022. We include randomized clinical trials and observational studies that reported the prevalence of spinal deformities (scoliosis and kyphosis) after congenital heart surgery among participants without these deformities before surgery. Two independent reviewers independently screened literature identified from the databases. Two reviewers independently conducted screening of studies identified during the search, data extraction, and quality assessment of the included studies.

RESULTS

In total, 688 studies were screened; 13 retrospective and one prospective cohort studies were included, encompassing 2294 participants. The pooled prevalence of spinal deformities (scoliosis and kyphosis) after open heart surgery performed on skeletally immature patients was 23.1% (95% confidence interval [CI] = 23.1-35.3; I2 = 97.5%).

CONCLUSION

This review suggests that the prevalence of spinal deformities was high among patients who underwent sternotomy or thoracotomy.

Short-term lumbar disc and lumbar stability changes of one-hole split endoscope technique treatment of spinal stenosis

OBJECTIVE

Investigating the early biomechanical effects of the one-hole split endoscope (OSE) technique on lumbar spine after decompression surgery.

METHODS

A retrospective analysis was conducted on 66 patients with lumbar spinal stenosis (LSS) who underwent OSE technique surgery at the affiliated hospital of Binzhou Medical University from September 2021 to September 2022. The patients had complete postoperative follow-up records. The mean age was (51.73 ± 12.42) years, including 33 males and 33 females. The preoperative and postoperative imaging data were analyzed, including disc height (DH), foraminal height (FH), lumbar lordosis angle (LLA), changes in disc angle, anterior-posterior translation distance, and lumbar intervertebral disc Pfirrmann grading. The visual analogue scale (VAS) was applied to evaluate the severity of preoperative, postoperative day 1, postoperative 3 months, and final follow-up for back and leg pain. The Oswestry Disability Index (ODI) was applied to assess the functionality at all the listed time points. The modified MacNab criteria were applied to evaluate the clinical efficacy at the final follow-up.

RESULTS

In 66 patients, there were statistically significant differences (p < 0.05) in DH and FH at the affected segments compared to preoperative values, whereas no significant differences (p > 0.05) were found in DH and FH at the adjacent upper segments compared to preoperative values. There was no statistically significant difference in the LLA compared to preoperative values (p > 0.05). Both the affected segments and adjacent upper segments showed statistically significant differences in Pfirrmann grading compared to preoperative values (p < 0.05). There were no statistically significant differences in the changes in disc angle or anterior-posterior translation distance in the affected or adjacent segments compared to preoperative values (p > 0.05). The VAS scores for back and leg pain, as well as the ODI, significantly improved at all postoperative time points compared to preoperative values. Among the comparisons at different time points, the differences were statistically significant (p < 0.05). The clinical efficacy was evaluated at the final follow-up using the modified MacNab criteria, with 51 cases rated as excellent, 8 cases as good, and 7 cases as fair, resulting in an excellent-good rate of 89.39%.

CONCLUSIONS

The OSE technique, as a surgical option for decompression in the treatment of LSS, has no significant impact on lumbar spine stability in the early postoperative period. However, it does have some effects on the lumbar intervertebral discs, which may lead to a certain degree of degeneration.

Can the Mismatch of Measured Pelvic Morphology vs. Lumbar Lordosis Predict Chronic Low Back Pain Patients?

Background: Measures of lumbar lordosis (LL) and elliptical modeling variables have been shown to discriminate between normal and chronic low back pain (CLBP) patients. Pelvic morphology influences an individual's sagittal lumbar alignment. Our purpose is to investigate the sensitivity and specificity of lumbar sagittal radiographic alignment and modeling variables to identify if these can discriminate between normal controls and CLBP patients. Methods: We conducted a computer analysis of digitized vertebral body corners on lateral lumbar radiographs of normal controls and CLBP patients. Fifty normal controls were attained from a required pre-employment physical examination (29 men; 21 women; mean age of 27.7 ± 8.5 years), with no history of low back pain, a normal spinal examination, no pathologies, anomalies, or instability. Additionally, 50 CLBP patients (29 men; 29.5 ± 8 years of age) were randomly chosen and matched to the characteristics of the controls. The inclusion criteria required no abnormalities on lumbar spine radiographs. The parameters included the following: ARA L1-L5 lordosis, ARA T12-S1 lordosis, Cobb T12-S1, b/a elliptical modelling ratio, sacral base angle (SBA), and S1 posterior tangent to vertical (PTS1). Two measures of pelvic morphology were determined for each person-the angle of pelvic incidence (API) and posterior tangent pelvic incidence angle (PTPIA)-and the relationships between API - ARA T12-S1, API - Cobb T12-S1, and API - ARA L1-5 was determined. Descriptive statistics and correlations among the primary variables were determined. The receiver operating characteristic curves (ROC curves) for primary variables were analyzed. Results: The mean values of LL were statistically different between the normal and CLBP groups (p < 0.001), indicating a hypo-lordotic lumbar spine for the CLBP group. The mean b/a ratio was lower in the chronic pain group (p = 0.0066). The pelvic morphology variables were similar between the groups (p > 0.05). API had a stronger correlation to the SBA and Cobb T12-S1 than PTPIA did, while PTPIA had a stronger correlation to the S1 tangent and ARA T12-S1 than API did. While CLBP patients had a stronger correlation of ARA T12-S1 and Cobb T12-S1 relative to the pelvic morphology, they also had a reduced correlation of ARA L1-L5 lordosis relative to their SBA and pelvic morphology measures. API - T12-S1, API - L1-L5, and API - Cobb T12-S1 were statistically different between the groups, p < 0.001. Using ROC curve analyses, it was identified that ARA L1-L5 lordosis of 36° and ARA T12-S1 of 68° have a good sensitivity and specificity to discriminate between normal and CLBP patients. ROC curve analyses identified that lordosis ARAT12-S1 < 68° (AUC = 0.83), lordosis ARAL1-L5 < 36° (AUC = 0.78), API - ARA T12-S1 < -18° (AUC = 0.75), API - ARAL1-L5 > 35° (AUC = 0.71), and API - Cobb T12-S1 < -5° (AUC = 0.69) had moderate to good discrimination between groups (AUC = 0.83, 0.78, 0.75, and 0.72). Conclusions: Pelvic morphology is similar between normal and CLBP patients. CLBP patients have an abnormal 'fit' of their API - ARAT12-S1 and L1-L5 lumbar lordosis relative to their pelvic morphology and sacral tilt shown as a hypolordosis.

Assessment of malalignment at early stage in adolescent idiopathic scoliosis: a longitudinal cohort study

INTRODUCTION

Our objective was to assess abnormalities of the odontoid-hip axis (OD-HA) angle in a mild scoliotic population to determine whether screening for malalignment would help predict the distinction between progressive and stable adolescent idiopathic scoliosis (AIS) at early stage.

MATERIALS AND METHODS

All patients (non-scoliotic and AIS) underwent a biplanar X-ray between 2013 and 2020. In AIS, inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10 years; and no previous treatment. A 3D spine reconstruction was performed, and the OD-HA was computed automatically. A reference corridor for OD-HA values in non-scoliotic subjects was calculated as the range [5th-95th percentiles]. A severity index, helping to distinguish stable and progressive AIS, was calculated and weighted according to the OD-HA value.

RESULTS

Eighty-three non-scoliotic and 205 AIS were included. The mean coronal and sagittal OD-HA angles in the non-scoliotic group were 0.2° and -2.5°, whereas in AIS values were 0.3° and -0.8°, respectively. For coronal and sagittal OD-HA, 27.5% and 26.8% of AIS were outside the reference corridor compared with 10.8% in non-scoliotic (OR = 3.1 and 3). Adding to the severity index a weighting factor based on coronal OD-HA, for thoracic scoliosis, improved the positive predictive value by 9% and the specificity by 13%.

CONCLUSION

Analysis of OD-HA suggests that AIS patients are almost three times more likely to have malalignment compared with a non-scoliotic population. Furthermore, analysis of coronal OD-HA is promising to help the clinician distinguish between stable and progressive thoracic scoliosis.

Relationship between spinal structural damage and sagittal balance in axial spondyloarthritis: Is the thoracic spine the starting point?

OBJECTIVES

To assess the relationship between spinal structural damage, sagittal balance parameters and spine curvatures in patients with axial spondyloarthritis (axSpA).

MATERIAL AND METHODS

In this cross-sectional study, the pelvic and sagittal balance parameters were obtained through EOS® (Biospace, Paris, France). Patients were divided into three groups according to the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) tertiles (G1 ≤6, n = 36; G2: 6.1-31, n = 36; G3 >31, n = 35) and pelvic and sagittal parameters were compared across them. Multivariable regression analysis was performed to analyze the impact of spinal structural damage and of other factors on sagittal vertical axis (SVA), an important sagittal balance parameter.

RESULTS

A total of 107 patients was included. G2 and 3 exhibited higher mean values of thoracic kyphosis T1-T12 when compared to G1 (10.5°(12.3) vs. 22.3°(17.3) vs. 35.2°(14.6), p < 0.001), and G3 demonstrated lumbar L1-S1 straightening compared to the other groups (55.7°(9) and 50.7°(19.8), G1 and G2, respectively, vs. 35.7°(13.2), p < 0.001). Mean SVA values showed an increasing gradient from G1 to G3 (21.6(25.1) vs. 41(44.3) vs. 84.3(47.2)mm, p < 0.001). In the multivariable regression, a one-unit increase in total mSASSS was associated with an average 0.8 mm higher SVA.

CONCLUSIONS

Our data showed that more spinal structural damage is associated with a higher SVA, reflecting poorer sagittal balance. Patients with increasing spinal damage have an important increase in thoracic kyphosis suggesting that postural modifications in patients with axSpA might have their origin in the thoracic spine.

Sex-based differences in clinical and radiological presentation of patients with degenerative lumbar scoliosis: a cross-sectional study

BACKGROUND

To evaluate the sex-based differences in clinical and radiological presentation of patients with degenerative lumbar scoliosis (DLS) and to explore whether the difference is helpful in investigating the etiology and progression of DLS.

METHOD

A retrospective review of 199 patients (41 males, 158 females) with DLS was included. Patient demographics including age, gender, bone mineral density were collected. Back and leg pain was assessed by visual analog scale, and general physical condition was assessed by Oswestry Disability Index. Cobb's angle was measured, and direction of scoliosis, position of the superior, inferior and apex vertebrae, number of vertebrae included in the scoliosis, rotation of apex vertebrae (Nash-Mo index), translation of apex vertebrae were recorded. Sagittal longitudinal axis, thoracolumbar kyphosis, lumbar lordosis (LL), pelvic incidence angle (PI), sacral slope, apex of lumbar lordosis and coronal balance distance were measured by whole spine lateral radiographs, and type of coronal imbalance was evaluated in all patients. Fat infiltration rate (FIR) of the paraspinal muscles at the vertebral apex was measured by MRI.

RESULT

Compared to female patients, male patients showed more back and leg pain on clinical presentation and smaller Cobb angle, less parietal rotation, larger LL, smaller PI-LL and lower paravertebral muscle FIR on radiologic features.

CONCLUSION

Gender differences do exist in DLS patients with regard to clinical and radiological presentation, low back pain was more pronounced in male patients, and scoliosis was more severe in female patients based on this cross-sectional study.

Sedentary lifestyle of university students is detrimental to the thoracic spine in men and to the lumbar spine in women

BACKGROUND

Sitting for long periods of time and lack of physical activity in young adults can cause postural deterioration leading to rapid onset of fatigue and increase the risk of back pain. We were interested in whether there are gender differences in spinal curvature among university students with a predominantly sedentary lifestyle.

METHODS

20 sedentary female (age 20 ± 0.73 years) and 39 sedentary male university students (age 20 ± 1.08 years) participated in this study. Their thoracic and lumbar curvatures were assessed while standing and sitting using a Spinal Mouse.

RESULTS

In standing, 80.0% of the females and 69.2% of the males had a neutral position of the thoracic spine (33.25° and 35.33°, respectively). However, more males, 30.8%, than females, 10.0%, had hyperkyphosis (54.27° and 47.0°, respectively). Hypokyphosis was found in 10.0% of the females (18.50°) and none in the males. Similarly, 90.0% of the females and 97.4% of the males had neutral position of the lumbar spine (-33.11° and -29.76°, respectively). Increased hyperlordosis was found in 10.0% of the females and 2.6% of the males (-41.0° and -50.0°, respectively). Hypolordosis was not detected in either females or males. In sitting, on the other hand, 70.0% of the females and only 33.3% of the males had a neutral position of the thoracic spine (30.20° and 30.62°, respectively). Increased hyperkyphosis was found in 46.2% of the males (59.76°) and none of the females. 30.0% of the females and 23.1% of the males had light hypokyphosis (47.50° and 46.67°, respectively). Similarly, 70.0% of the females and only 38.5% of the males had a neutral position of the lumbar spine (7.0° and 6.6°, respectively). 35.9% of the males and only 5.0% of the females had a light hypokyphosis (16.14° and 16.0°, respectively). Slightly increased hyperkyphosis was identified in 25.6% of the males and 25.0% of the females (23.9° and 22.5°, respectively).

CONCLUSION

There are significant gender differences in spinal curvature. While in the thoracic spine it was to the detriment of the males when both standing and sitting, in the lumbar spine it is related to the females only when standing. It is therefore necessary to eliminate these spinal deviations in young adults induced by prolonged sitting during university courses by appropriate recovery modalities.

Achievement and Maintenance of Optimal Alignment After Adult Spinal Deformity Corrective Surgery: A 5-Year Outcome Analysis

OBJECTIVE

We sought to assess factors contributing to optimal radiographic outcomes.

METHODS

Operative adult spinal deformity (ASD) patients with baseline and 5-year (5Y) data were included. Optimal alignment (O) was defined as improving in at least 1 Scoliosis Research Society-Schwab modifier without worsening in any Scoliosis Research Society-Schwab modifier. A robust outcome was defined as having optimal alignment 2 years (2Y) post operation that was maintained at 5Y. Predictors of robust outcomes were identified using multivariate regression analysis, with a conditional inference tree for continuous variables.

RESULTS

Two-hundred and ninety-seven ASD patients met inclusion criteria. Most patients (77.4%) met O at 6W, which decreased to 54.2% at 2Y. The majority of patients (89.4%) that met O at 2Y went on to meet radiographic durability at 5Y (48.5% of total cohort). Rates of junctional failure were higher in O2+5- compared with O2+5- (P = 0.013), with reoperation rates of 17.2% due to loss of alignment. Multivariable regression identified the following independent predictors of optimal alignment at 5Y in those that had O at 2Y: inadequate correction of pelvic tilt and overcorrection of the difference between pelvic incidence and lumbar lordosis (P < 0.05). Increased age, body mass index, and invasiveness were the most significant nonradiographic predictors for not achieving 5Y durability (P < 0.05).

CONCLUSIONS

The durability of optimal alignment after ASD corrective surgery was seen in about half of the patients at 5Y. While the majority of patients at 2Y maintained their radiographic outcomes at 5Y, major contributors to loss of alignment included junctional failure and adjacent region compensation, with only a minority of patients losing correction through the existing construct. The reoperation rate for loss of alignment was 17.2%. Loss of alignment requiring reoperation had a detrimental effect on 5Y clinical outcomes.

Lasso Analysis of Gait Characteristics and Correlation with Spinopelvic Parameters in Patients with Degenerative Lumbar Scoliosis

PURPOSE

This study quantifies the gait characteristics of patients with degenerative lumbar scoliosis (DLS) and patients with simple lumbar spinal stenosis (LSS) by means of a three-dimensional gait analysis system, aiming to determine the image of spinal deformity on gait and the correlation between spinal-pelvic parameters and gait characteristics in patients with DLS to assist clinical work.

METHODS

From June 2020 to December 2021, a total of 50 subjects were enrolled in this study, of whom 20 patients with DLS served as the case group and 30 middle-aged and elderly patients with LSS were selected as the control group according to the general conditions (sex, age, and BMI) of the case group. Spinal-pelvic parameters were measured by full-length frontal and lateral spine films one week before surgery, and kinematics were recorded on the same day using a gait analysis system.

RESULTS

Compared to the control group, DLS patients exhibited significantly reduced velocity and cadence; gait variability and symmetry of both lower limbs were notably better in the LSS group than in the DLS group; joint ROM (range of motion) across multiple dimensions was also lower in the DLS group; and correlation analysis revealed that patients with a larger Cobb angle, T1PA, and higher CSVA tended to walk more slowly, and those with a larger PI, PT, and LL usually had smaller stride lengths. The greater the PI-SS mismatch, the longer the patient stayed in the support phase. Furthermore, a larger Cobb angle correlated with worse coronal hip mobility.

CONCLUSIONS

DLS patients demonstrate distinctive gait abnormalities and reduced hip mobility compared to LSS patients. Significant correlations between crucial spinopelvic parameters and these gait changes underline their potential influence on gait disturbances in DLS. Our study identifies a Cobb angle cut-off of 16.1 as a key predictor for gait abnormalities. These insights can guide personalized treatment and intervention strategies, ultimately improving the quality of life for DLS patients.

The three-dimensional coupling mechanism in scoliosis and its consequences for correction

INTRODUCTION

In idiopathic scoliosis, the anterior spinal column has rotated away from the midline and has become longer through unloading and expansion of the intervertebral discs. Theoretically, extension of the spine in the sagittal plane should provide room for this longer anterior spinal column, allowing it to swing back towards the midline in the coronal and axial plane, thus reducing both the Cobb angle and the apical vertebral rotation.

METHODS

In this prospective experimental study, ten patients with primary thoracic adolescent idiopathic scoliosis (AIS) underwent MRI (BoneMRI and cVISTA sequences) in supine as well as in an extended position by placing a broad bolster, supporting both hemi-thoraces, under the scoliotic apex. Differences in T4-T12 kyphosis angle, coronal Cobb angle, vertebral rotation, as well as shape of the intervertebral disc and shape and position of the nucleus pulposus, were analysed and compared between the two positions.

RESULTS

Extension reduced T4-T12 thoracic kyphosis by 10° (p < 0.001), the coronal Cobb angle decreased by 9° (p < 0.001) and vertebral rotation by 4° (p = 0.036). The coronal wedge shape of the disc significantly normalized and the wedged and lateralized nucleus pulposus partially reduced to a more symmetrical position.

CONCLUSION

Simple extension of the scoliotic spine leads to a reduction of the deformity in the coronal and axial plane. The shape of the disc normalizes and the eccentric nucleus pulposus partially moves back to the midline.

Effect of spinal-pelvic sagittal balance on the clinical outcomes after lumbar fusion surgery

BACKGROUND

Spinal-pelvic sagittal balance is important for maintaining energy-efficient posture in normal and diseased states.Few reports to date have evaluated the effect of spinal-pelvic sagittal balance on clinical outcomes after lumbar interbody fusion in patients with lumbar degenerative diseases (LDD).

METHODS

A total of 303 patients treated with posterior lumbar interbody fusion surgery for lumbar degenerative disease from January 2012 to December 2019 were enrolled in this retrospective study according to the inclusion criteria. Preoperative and postoperative spinal-pelvic sagittal parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL) of the patients were evaluated and compared. 163 patients whose postoperative PI-LL ≤ 10° were divided into the spinal-pelvic match group (Group M), while 140 patients were divided into the spinal-pelvic mismatch group (Group MM). Preoperative and postoperative Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back pain of both groups were compared.

RESULTS

There was no significant difference between the two groups in demographic and surgical data, except for blood loss in surgery. LL, PI, PT and SS of the patients at final follow-up were all statistically different from the preoperative values in the two groups(P < 0.05). There was no significant difference in LL, PI, PT and SS between the two groups before surgery. At the final follow-up, LL, PI and PT differed significantly between the two groups(P < 0.05). Compared with the preoperative results, ODI and VAS of low back in both groups decreased significantly at the final follow-up (P < 0.05). Significant differences in VAS and ODI were found between the two groups at the final follow-up (P < 0.05). The improvement rates of VAS and ODI of Group M are both significantly higher than Group MM. Regression analysis showed that age and spinal-pelvic match had significant effects on the improvement of patients' low back pain at the final follow-up.

CONCLUSIONS

lumbar interbody fusion can significantly improve the prognosis of patients with LDD. In terms of outcomes with an average follow-up time of more than 2 years, the spinal-pelvic match has a positive effect on patients' quality of life and the release of low back pain.

Correlation between Degenerative Thoracolumbar Kyphosis and Lumbar Posterior Muscle

The relationship between spinal alignment, particularly degenerative thoracolumbar kyphosis (DTLK) combined with lumbar spine stenosis (LSS), and paraspinal muscle content remains underexplored. This study aimed to elucidate the characteristics of paraspinal muscle distribution in DTLK patients and its association with lumbar lordosis (LL) and body mass index (BMI).

METHODS

A case-control study was conducted comparing 126 patients with DTLK and LSS against 87 control patients. The lumbar crossing indentation value (LCIV) was introduced as a novel measurement for paraspinal muscle content, and its relationship with thoracolumbar kyphosis (TLK), BMI, and LL was assessed.

RESULTS

LCIV in DTLK patients was found to be lower than in the control group, with a progressive increase from the upper to lower lumbar spine. In the control group, paraspinal muscle content was observed to increase with age and BMI, and LCIV was higher in males. However, the DTLK group showed no gender difference. LCIV in the DTLK group was more pronounced in patients with increased LL. The degree of TLK was not influenced by BMI but was associated with the content of the paravertebral muscle.

CONCLUSIONS

Paraspinal muscle content, as measured by LCIV, is significantly associated with DTLK and LSS. The study emphasizes the importance of considering paraspinal muscle health in DTLK patients and offers valuable insights for diagnosis and therapeutic interventions.

PreOperative Planning for Adult Spinal Deformity Goals: Level Selection and Alignment Goals

Adult Spinal Deformity (ASD) is a complex pathologic condition with significant impact on quality of life, including pain, loss of function, and fatigue. Achieving realignment goals is crucial for long-term results. Reliable preoperative planning strategies, including nomograms, measurement tools, and level selection, are key to maximizing the likelihood of achieving a good outcome following ASD corrective surgery. This review covers recent literature on such strategies, including review of the different targets for realignment and their association with outcomes (both patients-reported outcomes and complications), selection of upper and lower instrumented vertebrae, and the latest innovation in preoperative planning for deformity surgery.

Sagittal balance parameters in achondroplasia

Introduction

Lumbar spinal stenosis (LSS) is the main problem for adult achondroplasia (Ach). Sagittal imbalance of the spine may play a role in LSS causing neurogenic claudication in Ach patients.

Research question

The purpose of this study is to describe the sagittal balance parameters in Ach patients.

Methods

A single-centre retrospective study of Ach patients that visited the Neurosurgery outpatient clinic of the Leiden University Medical Centre (LUMC) between 2019 and 2022 was performed. We defined sagittal imbalance by a C7 sagittal vertical axis (SVA) of more than 10 mm.

Results

There were 13 patients with a spinal sagittal imbalance and 15 patients with a balanced spine. In both groups, the sacral slope (SS) was comparable (45.0° and 49.0°, p = 0.305), but exceeding the mean SS in non achondroplasts (38.0°). Lumbar lordosis (LL) was more pronounced in the balanced group (55.5° versus 41.7°, p = 0.019), and positively correlated to SS in contrast to the absence of a correlation in the imbalanced group. Thoracolumbar kyphosis (TLK) was increased comparably in both groups (19.6° and 24.6°), and far exceeding the TLK in non achondroplasts (circa 0°), and in both groups negatively correlated with the LL, although not enough to compensate for the smaller LL in the imbalanced group.

Conclusion

Only if the LL compensates for both a larger SS and TLK, the Ach spine can maintain sagittal balance. An explanation for the current data can be the failure of the lumbar spine to give sufficient lordosis due to degenerative processes.

Correlation Between Sagittal Balance and Mechanical Distal Junctional Failure in Degenerative Pathology of the Spine: A Retrospective Analysis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

This study aimed to investigate the failure of the caudal end of lumbar posterior fixation in terms of pre-operative and post-operative spinopelvic parameters, correction performed, demographic and clinical data.

METHODS

The lumbar, thoraco-lumbar and lumbo-sacral posterior fixations performed with pedicle screws and rods in 2017-2019 were retrospectively analyzed. As 81% failures occurred within 4 years, an observational period of 4 years was chosen. The revision surgeries due to the failure in the caudal end were collected in the junctional group. Fixations which have not failed were gathered in the control group. The main spinopelvic parameters were measured for each patient on standing lateral radiographs with the software Surgimap. Demographic and clinical data were extracted for both groups.

RESULTS

Among the 457 patients who met the inclusion criteria, the junctional group included 101 patients, who required a revision surgery. The control group collected 356 primary fixations. The two most common causes of revision surgeries were screws pullout (57 cases) and rod breakage (53 cases). SVA, PT, LL, PI-LL and TPA differed significantly between the two groups (P = .021 for LL, P < .0001 for all the others). The interaction between the two groups and the pre-operative and post-operative conditions was significant for PT, SS, LL, TK, PI-LL and TPA (P < .005). Sex and BMI did not affect the failure onset.

CONCLUSIONS

Mechanical failure is more likely to occur in patients older than 40 years with a thoraco-lumbar fixation where PT, PI-LL and TPA were not properly restored.

Prediction of subsequent vertebral compression fractures after thoracolumbar kyphoplasty: a multicenter retrospective analysis

OBJECTIVE

Second fractures at the cemented vertebrae (SFCV) are often seen after percutaneous kyphoplasty, especially at the thoracolumbar junction. Our study aimed to develop and validate a preoperative clinical prediction model for predicting SFCV.

METHODS

A cohort of 224 patients with single-level thoracolumbar osteoporotic vertebral fractures (T11-L2) from 3 medical centers was analyzed between January 2017 and June 2020 to derive a preoperative clinical prediction model for SFCV. Backward-stepwise selection was used to select preoperative predictors. We assigned a score to each selected variable and developed the SFCV scoring system. Internal validation and calibration were conducted for the SFCV score.

RESULTS

Among the 224 patients included, 58 had postoperative SFCV (25.9%). The following preoperative measures on multivariable analysis were summarized in the 5-point SFCV score: bone mineral density (≤-3.05), serum 25-hydroxy vitamin D3 (≤17.55 ng/mL), standardized signal intensity of fractured vertebra on T1-weighted images (≤59.52%), C7-S1 sagittal vertical axis (≥3.25 cm), and intravertebral cleft. Internal validation showed a corrected area under the curve of 0.794. A cutoff of ≤1 point was chosen to classify a low risk of SFCV, for which only 6 of 100 patients (6%) had SFCV. A cutoff of ≥4 points was chosen to classify a high risk of SFCV, for which 28 of 41 (68.3%) had SFCV.

CONCLUSION

The SFCV score was found to be a simple preoperative method for identification of patients at low and high risk of postoperative SFCV. This model could be applied to individual patients and aid in the decision-making before percutaneous kyphoplasty.

Differences in Involvement of Whole-Body Compensatory Alignment for Decompensated Spinopelvic Sagittal Balance

BACKGROUND

The aim of this study was to investigate the differences in the involvement of whole-body compensatory alignment in different conditions of spinopelvic sagittal balance (compensated/decompensated).

METHODS

We enrolled 330 individuals who underwent medical checkups and divided them according to sagittal vertical axis (SVA): for the compensated group, this was <4 cm, (group C) and for the decompensated group, it was ≥4 cm, (group D). The correlation between the lack of ideal lumbar lordosis (iLL), which was calculated by using the Schwab formula, and the compensatory radiographic parameters in each group was analyzed. The threshold value of knee flexion (KF) angle, which indicated spinopelvic sagittal imbalance (SVA ≥ 4), was determined by a ROC-curve analysis.

RESULTS

The correlation analysis of the lack of iLL and each compensatory parameter showed a strong correlation for pelvic tilt (PT) (r = -0.723), and a weak correlation for thoracic kyphosis (TK) (r = 275) in Group C. In Group D, the correlations were strong for PT (r = -0.796), and moderate for TK (r = 0.462) and KF (r = -0.415). The optimal cutoff value for the KF angle was determined to be 8.4 degrees (sensitivity 89%, specificity 46%).

CONCLUSIONS

The present study shows differences between compensated/decompensated spinopelvic sagittal balance in the correlation strength between lack of iLL and whole-body compensatory parameters.

The influence of osteoporotic vertebral fractures on global sagittal alignment in elderly patients: a systematic review and meta-analysis

BACKGROUND

Thoracic kyphosis, or loss of lumbar lordosis, is often equated with osteoporosis because vertebral fractures are assumed to be a major causative factor, in addition to degeneration related to age. Despite the few studies aiming to measure the natural change in global sagittal alignment (GSA) that occurs with advancing age, the overall effect of conservatively managed osteoporotic vertebral compression fractures (OVCF) on the GSA in the elderly remains poorly understood.

OBJECTIVE

To systematically evaluate the relevant literature regarding the influence of OVCF on the GSA compared to patients of similar age without fractures using the following radiological parameters: Pelvic Incidence (PI), Pelvic Tilt (PT), Lumbar Lordosis (LL), Thoracic Kyphosis (TK), Sagittal Vertical Axis (SVA) and Spino-sacral Angle (SSA).

METHODS

A systematic review of the English language literature dating up until October 2022, was undertaken utilizing the PRISMA guidelines.

RESULTS

Of a total of 947 articles, 10 studies met the inclusion criteria (4 Level II, 4 level III and 2 level IV evidence) and were subsequently analyzed. Overall, 584 patients (8 studies) of mean age 73.7 years (69.3-77.1) had acute OVCF of one or more vertebra that were managed conservatively. The male to female ratio was 82:412. Five studies mentioned the number of fractured vertebrae, with a total of 393 in 269 patients (average of 1.4 fractured vertebrae per patient). Their pre-operative radiological parameters on standing X-rays showed a mean PI of 54.8°, PT 24°, LL 40.8°, TK 36.5°, PI-LL 14°, SVA 4.8 cm, and SSA 115°. In addition, 437 patients were used as a control group with osteoporosis without fractured vertebrae, (6 studies) with an average age of 72.4 years (67-77.8) and male to female ratio of 96:210 (5 studies). They all had upright X-rays to assess their global sagittal alignments. Radiological parameters showed an average PI of 54.3°, PT 17.3°, LL 43.4°, TK 31.25°, PI-LL 10.95°, SVA 1.27 cm and SSA 125°. A statistical analysis comparing the OVCF group with the control group (4 studies), showed a significant increase in PT of 5.97° (95%CI 2.63, 9.32; P < 0.0005), a significant increase in TK by 8.28° (95%CI 2.15, 14.4; P < 0.008), an increase in PI-LL by 6.72° (95%CI 3.39, 10.04; P < 0.0001), an increase in SVA by 1.35 cm (95%CI 0.88, 1.83; P < 0.00001), and a decrease in SSA by 10.2° (95%CI 10.3, 23.4; P < 0.00001).

CONCLUSION

Osteoporotic vertebral compression fractures managed conservatively appear to be a significant causate factor of global sagittal imbalance.

Effects of a Pilates programme in spinal curvatures and hamstring extensibility in adolescents with thoracic hyperkyphosis: a randomised controlled trial

AIM

To evaluate the effects of a 9-month Pilates exercise programme on the sagittal spinal posture and hamstring extensibility of adolescents with thoracic hyperkyphosis.

DESIGN

Randomised controlled trial with blinded examiner.

PATIENTS

One-hundred and three adolescents with thoracic hyperkyphosis.

INTERVENTIONS

Participants were randomly placed into an experimental group which participated in a Pilates exercise programme implemented for a total of 38 weeks (two sessions/week, 15 min/session) (Pilates group (PG), sample = 49, or control group (CG), sample = 48).

MAIN OUTCOME MEASURES

The outcome measures were the thoracic curve in sagittal spinal curvature in relaxed standing, sagittal spinal curvatures and pelvic tilt in relaxed standing and sit-and-reach positions, and hamstring extensibility.

RESULTS

There was a significant adjusted mean difference between groups in favour of the PG in the thoracic curve in relaxed standing position (-5.6°, p = 0.003), pelvic tilt (-2.9°, p = 0.03) and all straight leg tests (p<0.001). The PG showed a significant change in thoracic curve (-5.9, p<0.001) and in lumbar angle (4.0, p = 0.001) in relaxed standing position and in all straight leg raise tests (+6.4 to +15°, p<0.0001).

CONCLUSIONS

The adolescents with thoracic hyperkyphosis from the PG had a decreased thoracic kyphosis in relaxed standing position, and improved hamstring extensibility as compared with the CG. More than 50% of the participants obtained kyphosis values inside normality, showing an adjusted mean difference between groups in the thoracic curve of about 73% of the baseline mean, resulting in a large improvement and high clinical importance.

TRIAL REGISTRATION NUMBER

NCT03831867.

Sagittal Spinal Alignment in People with Chronic Spinal Cord Injury and Normal Individual: A Comparison Study Using 3D Ultrasound Imaging

The aim of this study was to compare the sagittal spinal alignment of people with chronic spinal cord injury (SCI) with normal individuals and to determine whether transcutaneous electrical spinal cord stimulation (TSCS) could cause a change in the thoracic kyphosis (TK) and lumbar lordosis (LL) to re-establish normal sagittal spinal alignment. A case series study was conducted, wherein twelve individuals with SCI and ten neurologically intact subjects were scanned using 3D ultrasonography. In addition, three people with SCI having complete tetraplegia participated further to receive a 12-week treatment (TSCS with task-specific rehabilitation) after evaluation of sagittal spinal profile. Pre- and post-assessments were conducted to evaluate the differences in sagittal spinal alignment. The results showed that the TK and LL values for a person with SCI in a dependent seated posture were greater than those of normal subjects for: standing (by TK: 6.8° ± 1.6°; LL: 21.2° ± 1.9°), sitting straight (by TK: 10.0° ± 4.0°; LL: 1.7° ± 2.6°), and relaxed sitting (by TK: 3.9° ± 0.3°; LL: 7.7° ± 1.4°), respectively, indicating an increased risk for spinal deformity. In addition, TK decreased by 10.3° ± 2.3° after the TSCS treatment, showing a reversible change. These results suggest that the TSCS treatment could be used to restore normal sagittal spinal alignment for individuals with chronic SCI.

Sagittal realignment: surgical restoration of the global alignment and proportion score parameters: a subgroup analysis. What are the consequences of failing to realign?

INTRODUCTION

The Global Alignment and Proportion (GAP) score incorporates three domains directly modified with surgery (relative pelvic version-RPV, relative lumbar lordosis-RLL, lumbar distribution index-LDI) and one indirectly restored (relative spinopelvic alignment-RSA). We analyzed our surgical realignment performance and the consequences of domain-specific realignment failure on mechanical complications and PROMs.

MATERIALS AND METHODS

From an adult spinal deformity prospective multicenter database, we selected patients: fused to pelvis, upper instrumented vertebra at or above L1, and 2 years of follow-up. Descriptive, univariate and multivariate analyses were employed.

RESULTS

The sample included 333 patients. RLL-6w showed the highest success rate (58.3% aligned), but 16.5% of patients were classified in the "Severe hypolordosis" and "Hyperlordosis" subgroups. RPV-6w was the most challenging to realign, with 51.6% moderate or severe retroversion. Regarding RSA-6w, 21.9% had severe positive malalignment. Correct alignment of RPV-6w (p = 0.025) and RSA-6w (p = 0.002) proved to be protective factors against the development of mechanical complications. Severe pelvic retroversion (p = 0.026) and severe positive malalignment (p = 0.007) were risk factors for mechanical complications. RSA-6w "Severe positive malalignment" was associated with less improvement in PROMs: ∆ODI (8.83 vs 17.2; p = 0.011), ∆SRS-22 total (0.54 vs 0.87; p = 0.007), and ∆SF-36PCS (3.47 vs 7.76; p = 0.04); MCID for ODI (37.0 vs 55.5%; p = 0.023), and SRS-22 (40.8 vs 60.1%; p = 0.015); and PASS for ODI (17.6 vs 31.7%; p = 0.047).

CONCLUSIONS

RPV was the most underperformed modifiable parameter. Severe pelvic retroversion and severe positive malalignment influenced the occurrence of mechanical complications. Severe positive malalignment affected PROMs improvement.

Isokinetic strength assessment of trunk muscle and its relationship with spinal-pelvic parameters in patients with degenerative spinal deformity

BACKGROUND

The incidence rate of degenerative spinal deformity (DSD) has gradually increased in the elderly. Currently, the relationship between the functional status of trunk muscle and the spinal-pelvic parameters of DSD patients remains unclear.

OBJECTIVE

This paper aims to explore the relationship between the two factors and provide new clues for exploring the mechanism of the occurrence and development of DSD.

METHODS

A total of 41 DSD patients treated in our hospital (DSD group) and 35 healthy volunteers (control group) were selected. Muscle strength was evaluated using an IsoMed-2000 isokinetic dynamometer, and the trunk flexor and extensor peak torque (PT) of subjects was measured at a low, medium, and high angular velocity of 30∘/s, 60∘/s, and 120∘/s, respectively. Hand grip strength (HGS) was assessed using an electronic grip dynamometer and Surgimap software was used to measure the spinal-pelvic parameters, including the sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence rate (PI), and PI-LL, and the relationship between trunk muscle function and various parameters was analyzed.

RESULTS

Under the three angular velocities, the flexor and extensor PT values in the DSD group were lower than those in the control group, and only the extensor PT showed a statistically significant difference (P< 0.05). There was no significant difference in HGS between the two groups (P> 0.05). In the DSD group, the extensor PT at 30∘/s was significantly negatively correlated with SVA (P< 0.05). At 60∘/s and 120∘/s, the extensor PT was significantly negatively correlated with SVA and PT (P< 0.05).

CONCLUSION

Trunk extensor strength is significantly lower in DSD patients than in normal controls. The decline in trunk extensor strength in DSD patients is a type of local muscle dysfunction more closely related to the deformity, which is likely involved in the compensatory mechanism of DSD and may reflect the overall imbalance of the trunk.

Immediate Effects of Isolated Lumbar Extension Resistance Exercise (ILEX) on Spine Posture and Mobility Measured with the IDIAG Spinal Mouse System

Posture and mobility are important aspects for spinal health. In the context of low back pain, strategies to alter postural anomalies (e.g., hyper/hypolordosis, hyper/hypokyphosis) and mobility deficits (e.g., bending restrictions) have been of interest to researchers and clinicians. Machine-based isolated lumbar extension resistance exercise (ILEX) has been used successfully for rehabilitation of patients suffering from low back pain. The aim of this study was to analyse the immediate effects of ILEX on spinal posture and mobility. In this interventional cohort study, the posture and mobility measures of 33 healthy individuals (m = 17, f = 16; mean age 30.0 years) were taken using the surface-based Spinal Mouse system (IDIAG M360©, Fehraltdorf, Switzerland). Individuals performed one exercise set to full exhaustion with an ILEX-device (Powerspine, Wuerzburg, Germany) in a standardized setup, including uniform range of motion and time under tension. Scans were made immediately before and after the exercise. There was an immediate significant decrease in standing lumbar lordosis and thoracic kyphosis. No change could be observed in standing pelvic tilt. Mobility measures showed a significant decrease in the lumbar spine and an increase in the sacrum. The results show that ILEX alters spine posture and mobility in the short-term, which may benefit certain patient groups.

No Significant Radiological Signs of Adult Spinal Deformity Progression after a Mean of 11 Years of Follow-Up Following Harrington Rod Instrumentation Removal and Watchful Waiting

The study aimed to assess long-term radiological outcomes in patients from our institution who were primarily treated for adolescent idiopathic scoliosis with surgical correction using Harrington rod (HR) instrumentation, and afterward with watchful waiting of residual spinal deformity after HR removal, whereby no patient consented to spinal deformity correction. A single-institution case series of 12 patients was retrospectively evaluated. Preoperative and most recent post-instrumentation removal radiographic measurements were compared, along with baseline characteristics. The average age of patients (all females) at the time of HR instrumentation removal was 38 ± 10 years (median 40, range 19-54). The mean follow-up from the HR instrumentation implantation to the HR instrumentation removal was 21 ± 10 years (median 25, range 2-37), with a further mean of 11 ± 10 years (median 7, range 2-36) of follow-up following HR instrumentation removal and watchful waiting. No significant change in radiological parameters was observed: LL (p = 0.504), TK (p = 0.164), PT (p = 0.165), SS (p = 0.129), PI (p = 0.174), PI-LL (p = 0.291), SVA (p = 0.233), C7-CSVL (p = 0.387), SSA (p = 0.894), TPA (p = 0.121), and coronal Cobb angle (proximal (p = 0.538), main thoracic (p = 0.136), and lumbar (p = 0.413)). No significant change in coronal or sagittal parameters was observed in this single-institution long-term radiological outcome study of adults following HR instrumentation removal and watchful waiting of residual spinal deformity.

Loss of CSF-contacting neuron sensory function is associated with a hyper-kyphosis of the spine reminiscent of Scheuermann's disease

Scheuermann's disease, also referred to as Scheuermann's kyphosis, is the second most frequent spine deformity occurring in humans after adolescent idiopathic scoliosis (AIS), both with an unclear etiology. Recent genetic studies in zebrafish unraveled new mechanisms linked to AIS, highlighting the role of the Reissner fiber, an acellular polymer bathing in the cerebrospinal fluid (CSF) in close proximity with ciliated cells and mechanosensory neurons lining the central canal of the spinal cord (CSF-cNs). However, while the Reissner fiber and ciliary beating have been linked to AIS-like phenotypes in zebrafish, the relevance of the sensory functions of CSF-cNs for human spine disorders remains unknown. Here, we show that the thoracic hyper-kyphosis of the spine previously reported in adult pkd2l1 mutant zebrafish, in which the mechanosensory function of CSF-cNs is likely defective, is restricted to the sagittal plane and is not associated with vertebral malformations. By applying orthopedic criteria to analyze the amplitude of the curvature at the apex of the kyphosis, the curve pattern, the sagittal balance and sex bias, we demonstrate that pkd2l1 knock-outs develop a phenotype reminiscent of Scheuermann's disease. Altogether our work consolidates the benefit of combining genetics and analysis of spine deformities in zebrafish to model idiopathic spine disorders in humans.

Characteristics of the paravertebral muscle in adult degenerative scoliosis with PI-LL match or mismatch and risk factors for PI-LL mismatch

Objective

Pelvic incidence (PI) minus the lumbar lordosis (LL) angle (PI-LL) correlates with function and disability. It is associated with paravertebral muscle (PVM) degeneration and is a valuable tool for surgical planning of adult degenerative scoliosis (ADS). This study aims to explore the characteristics of PVM in ADS with PI-LL match or mismatch and to identify the risk factors for PI-LL mismatch.

Methods

A total of 67 patients with ADS were divided into PI-LL match and mismatch groups. The visual analog scale (VAS), symptom duration, and Oswestry disability index (ODI) were used to assess patients’ clinical symptoms and quality of life. The percentage of fat infiltration area (FIA%) of the multifidus muscle at the L1-S1 disc level was measured by using MRI with Image-J software. Sagittal vertical axis, LL, pelvic tilt (PT), PI, sacral slope, and the asymmetric and average degeneration degree of the multifidus were recorded. Logistic regression analysis was done to identify the risk factors for PI-LL mismatch.

Results

In the PI-LL match and mismatch groups, the average FIA% of the multifidus on the convex side was less than that on the concave side (P &lt; 0.05). There was no statistical difference of asymmetric degeneration degree of the multifidus between the two groups (P &gt; 0.05). In the PI-LL mismatch group, the average degeneration degree of the multifidus, VAS, symptom duration, and ODI were significantly higher than that in the PI-LL match group, respectively (32.22 ± 6.98 vs. 26.28 ± 6.23 (%), 4.33 ± 1.60 vs. 3.52 ± 1.46, 10.81 ± 4.83 vs. 6.58 ± 4.23 (month), 21.06 ± 12.58 vs. 12.97 ± 6.49, P &lt; 0.05). The average degeneration degree of the multifidus muscle was positively correlated with the VAS, symptom duration, and ODI, respectively (r = 0.515, 0.614, and 0.548, P &lt; 0.05). Sagittal plane balance, LL, PT, and the average degeneration degree of the multifidus were the risk factors for PI-LL mismatch (OR: 15.447, 95% CI: 1.274–187.269; OR: 0.001, 95% CI: 0.000–0.099; OR: 107.540, 95% CI: 5.195–2,225.975; OR: 52.531, 95% CI: 1.797–1,535.551, P &lt; 0.05).

Conclusion

The PVM on the concave side was larger than that on the convex side in ADS irrespective of whether PI-LL matched or not. PI-LL mismatch could aggravate this abnormal change, which is an important cause of pain and disability in ADS. Sagittal plane imbalance, decreased LL, higher PT, and larger average degeneration degree of the multifidus were independent risk factors for PI-LL mismatch.

Does kyphoplasty affect the global sagittal alignment in patients with osteoporotic vertebral fractures? A systematic review and meta-analysis

BACKGROUND

Osteoporotic vertebral compression fractures (OVCF) are common in elderly patients and may cause local kyphosis due to the vertebral collapse and wedging. Balloon kyphoplasty (BKP) with polymethyl methacrylate is widely used to relieve back pain and restore the height and kyphosis of the destroyed vertebra Johnell (Osteoporos Int 17(12):1726-33, 2006); Wasnich (Bone 18: 179S-183S, 1996); Finnern (Osteoporos Int 14:429-436, 2003). However, the influence of BKP on global sagittal alignment (GSA) in patients with OVCF remains unclear.

OBJECTIVE

To systematically evaluate the relevant literature regarding the influence of BKP on the global spinal sagittal alignment using the following radiological parameters: Pelvic Incidence (PI), Pelvic Tilt (PT), Lumbar Lordosis (LL), Thoracic Kyphosis (TK), Sagittal Vertical Axis (SVA) and Spinosacral Angle (SSA). Visual Analogue Score (VAS) was also recorded.

METHODS

A systematic review of the English language literature dating up until August 2022, was undertaken utilising the PRISMA guidelines.

RESULTS

Of a total of 548 articles, 4 studies met the inclusion criteria (4 level III evidence) and were analyzed. Overall, 201 patients of mean age 73.8 years (69-77) had acute OVCF of one or more vertebra. The male to female ratio was 51:128. The number of fractured vertebrae was 235 (average of 1.17 fractured vertebrae per patient). Their pre-operative radiological parameters on standing x-rays showed a mean PI of 56°, PT 24.1°, LL 44.4°, TK 42.3°, PI-LL 11.7°, SVA 4.9 cm, LL/TK 1 and SSA 114.8°. The average VAS was 7.6 (2.6-10). All the patients underwent BKP and their radiological parameters on standing x-rays post operatively showed a mean PI of 55.3°, PT 23.1°, LL 45.1°, TK 41.4°, PI-LL 10.3°, SVA 4.29 cm, LL/TK 1.07 and SSA 116.8°. Their average VAS post BPK was 2.36 (0-4.8).A statistical analysis comparing the pre/post-operative GSA (111 patients, 3 studies with standard deviations) showed no statistical difference in PT (24.1° vs. 23.5°, P = 0.93), TK (42.3° vs. 42.4°, P = 0.57), PI-LL (14.4° vs.12.4°, P = 0.4), SVA (6.1 cm vs. 5.5 cm, P = 0.19) SSA (114.8° vs. 116.7° P = 0.36). VAS was significantly reduced post BKP (7.1 vs. 2.5 P = 0.004).

CONCLUSION

Performing BKP procedures does not significantly affect the global sagittal alignment in patients with osteoporotic vertebral compression fractures. There was however, a significant improvement in pain scores in patients undergoing BKP at 1 or more levels.

Novel artificial intelligence algorithm: an accurate and independent measure of spinopelvic parameters

OBJECTIVE

The analysis of sagittal alignment by measuring spinopelvic parameters has been widely adopted among spine surgeons globally, and sagittal imbalance is a well-documented cause of poor quality of life. These measurements are time-consuming but necessary to make, which creates a growing need for an automated analysis tool that measures spinopelvic parameters with speed, precision, and reproducibility without relying on user input. This study introduces and evaluates an algorithm based on artificial intelligence (AI) that fully automatically measures spinopelvic parameters.

METHODS

Two hundred lateral lumbar radiographs (pre- and postoperative images from 100 patients undergoing lumbar fusion) were retrospectively analyzed by board-certified spine surgeons who digitally measured lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope. The novel AI algorithm was also used to measure the same parameters. To evaluate the agreement between human and AI-automated measurements, the mean error (95% CI, SD) was calculated and interrater reliability was assessed using the 2-way random single-measure intraclass correlation coefficient (ICC). ICC values larger than 0.75 were considered excellent.

RESULTS

The AI algorithm determined all parameters in 98% of preoperative and in 95% of postoperative images with excellent ICC values (preoperative range 0.85-0.92, postoperative range 0.81-0.87). The mean errors were smallest for pelvic incidence both pre- and postoperatively (preoperatively -0.5° [95% CI -1.5° to 0.6°] and postoperatively 0.0° [95% CI -1.1° to 1.2°]) and largest preoperatively for sacral slope (-2.2° [95% CI -3.0° to -1.5°]) and postoperatively for lumbar lordosis (3.8° [95% CI 2.5° to 5.0°]).

CONCLUSIONS

Advancements in AI translate to the arena of medical imaging analysis. This method of measuring spinopelvic parameters on spine radiographs has excellent reliability comparable to expert human raters. This application allows users to accurately obtain critical spinopelvic measurements automatically, which can be applied to clinical practice. This solution can assist physicians by saving time in routine work and by avoiding error-prone manual measurements.

Reciprocal Changes in the Whole-Body Following Realignment Surgery in Adult Spinal Deformity

The idea of the global balance of spine stems from Jean Dubousset, who first introduced the concept of cone of economy. Through the compensatory mechanisms, the human body maintains an upright posture and horizontal gaze in the setting of the spinal malalignment. Compensation takes place not only in the mobile spine segments, but also in the pelvis and lower extremities. Patients with a malalignment exhibit compensatory changes in the cervical hyper-lordosis, posterior pelvic shift, knee/ankle flexion, hip extension, and the pelvic retroversion. The advent of whole-body stereo radiography has yielded an improved understanding of global changes among the patients. Deformity-induced compensatory changes in the sagittal alignment could be resolved reciprocally after the surgical correction of the malalignment. Thoracolumbar realignment surgery restores the pathologic compensatory changes in the unfused spinal segments, pelvis, and the lower extremities. Similarly, reciprocal changes in the thoracolumbar spine may harmonize global sagittal alignment after the cervical reconstruction. This study reviews the compensatory mechanisms and reciprocal changes in global sagittal alignment caused by the surgical correction and highlights, the factors that should be considered while assessing a patient's compensatory status.

The Differences Between Same-Day and Staged (Circumferential) Fusion Surgery in Adult Spinal Deformity: Protocol for a Systematic Review

BACKGROUND

Adult spinal deformity (ASD) is a deformity in the curvature of the adult spine. ASD includes a range of pathology that leads to decreased quality of life for patients as well as debilitating morbidities. Treatment can range from nonoperative management to long-segment surgical corrections and depends greatly on the deformity and patient profiles. If surgical treatment is indicated, circumferential (a combined anterior and posterior approach) fusion is one of the tools in the spine surgeon's armamentarium. Depending on the complexity, the procedure is either completed on the same day or staged. Determining whether to perform a circumferential surgery in a staged fashion is based largely on the surgeon's preference and perception of the individual case complexity; at present, there is no high-quality evidence that can be used to support that decision.

OBJECTIVE

This paper presents the protocol for a systematic review that aims to investigate the differences between same-day versus staged circumferential fusion surgery in ASD both in patient selection and in outcomes.

METHODS

Searches will be performed on MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus. Gray literature and the reference lists of articles included in the full-text screening will also be screened for inclusion. Results will be exported to Covidence. Data will be collected on demographics, type of procedures performed, surgery levels, blood loss, total operation time, length of stay, disposition, readmissions (30 days and 90 days), and perioperative complications. Patient-reported outcomes will also be assessed. Data quality assessment of randomized controlled trials will be performed using the Cochrane Collaboration's tool for assessing risk of bias in randomized trials, and nonrandomized studies will be assessed with the ROBINS-I (Risk of Bias in Non-randomized Studies of Interventions) tool. All screening, quality assessment, and data extraction will be done by 2 independent reviewers. A descriptive synthesis will be performed, and data will be evaluated for further analysis.

RESULTS

This study is currently in the screening phase. There are no results yet. The search strategy has been developed and documented. Information has been exported to Covidence. Upon conclusion of the critical appraisal stage, screening and extraction, as well as a synthesis of the results, will be performed.

CONCLUSIONS

The intended review will summarize the differences in perioperative outcomes and complications between same-day and staged (circumferential) fusion surgery in adult spinal deformity. It will also describe the patients selected for such procedures based on their demographics and pathology. Identified gaps in knowledge will provide insight into current limitations and guide further studies on this topic.

TRIAL REGISTRATION

PROSPERO CRD42022339764; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=339764.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/42331.

"Reasonable threshold" of spinopelvic parameters after fixation on distal stenosis in patients with degenerative thoracolumbar kyphosis: A STROBE-compliant article

The short-segment instrument for precision treatment of lumbar stenosis syndrome (LSS) combined with degenerative thoracolumbar kyphosis (DTLK) receives more attention and the reasonable range of sagittal parameters is debatable in these elderly patients. This study aimed to include LSS patients combined with DTLK performed short-segmental fixation on LSS, to evaluate the efficacy of this procedure, and to determine the reasonable threshold of sagittal parameters. Overall 138 patients (female, 62.3%) were eligible (mean age of 68.8 ± 7.7 years) with a follow-up time of 24.6 ± 11.1 months. Spinopelvic sagittal parameters containing TLK, lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sagittal vertical axis were obtained at baseline and final visit, where |PI-LL|, PT, and sagittal vertical axis were seen as the main parameters. Quality of life was evaluated by the Oswestry Disability Index (ODI), which were divided into 4 quarters orderly. The reasonable threshold of parameters corresponding to ODI was determined by both linear regression and logistic regression. For all participants, TLK decreased by a mean of 8.3° and cases got TLK correction occupied 40.4%. ODI got improvement by the change of 29.9 ± 9.9. At baseline, ODI was correlated to |PI-LL|, while at final, ODI was correlated to |PI-LL| and PT. The independent factor affecting preoperative ODI was |PI-LL|, with ODI = 0.19 × |PI-LL| + 36.9 and the mean threshold of preoperative |PI-LL| was 10.7°. At final, PT was the influencing factor with ODI = 0.21 × PT + 3.16 and PT = 0.60 × |PI-LL| + 12.22. The mean threshold of postoperative |PI-LL| was 16.0° and PT was 23.1° by both linear regression and logistic regression. With short-segment fixation on LSS, >40% of patients with DTLK acquired TLK correction. |PI-LL| = 16.0° and PT = 23.1° was the "reasonable threshold" of sagittal parameters with the procedure for this population.

The Pelvic Incidence Stratified Sagittal Spinopelvic Alignment in Asymptomatic Chinese Population With Different Age Groups

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To provide the age- and pelvic incidence-related variations of sagittal alignment in asymptomatic Chinese population.

METHODS

This study recruited asymptomatic adult subjects. All subjects undertook the standing whole spinal radiograph and the sagittal parameters were measured: sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI) and pelvic tilt (PT). All subjects were divided into young, middle aged and elderly groups, then each age group was further divided into 5 subgroups (very low, low, average, high and very high) based on PI values. The relations between PI, age and other parameters were evaluated. The differences in sagittal parameters of each PI subgroup were compared.

RESULTS

546 subjects were included with an average age of 38.6 years (18 to 81). The number of subjects over 70 years and with very low PI was relatively small. The average of PI, TPA, PT and LL were 45.9° ± 8.4°, 6.4° ± 6.2°, 11.9° ± 6.6° and 49.2° ± 10.1°, respectively. SVA, TPA, TK and PT increased with age (P < 0.05), while SVA, TPA, PT, PI-LL also increased with PI (P < 0.05). LL, PT, TPA, PI-LL and LL-TK were different among the 5 PI subgroups (P < 0.05). However, the values of LL in elderly subjects with high and very high PI were similar.

CONCLUSION

The age- and PI-related variations in sagittal alignment of Chinese population were provided. The sagittal parameters were significantly influenced by age and PI. The individual pelvic morphology should be carefully considered during the assessment and restoration of sagittal balance.

Sagittal Parameters of Spine-Pelvis-Hip Joints in Patients with Lumbar Spinal Stenosis

Objective

To explore sagittal compensation characteristics, including extra spinal‐pelvic parameters and distal hip parameters, for analysis in middle‐aged to the older patients with lumbar spinal stenosis (LSS) without spinal deformity and clarify the fitting relationship between the main sagittal parameters.

Methods

This retrospective single‐center study included 205 patients with LSS in our department from January 2016 to December 2018, including 153 women (74.6%), with an average age of 67.6 ± 7.1 years. Sagittal parameters were obtained on the whole spinal lateral radiograph. Spinal parameters include thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), and lumbar lordosis (LL). Pelvic parameters include pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Hip parameters include pelvic rotation (PR) and hip inclination angle (HIA). Spine‐pelvic parameter is spino‐sacral angle (SSA). Sagittal balance parameter is sagittal vertical axis (SVA). PI‐LL, PT, SVA, HIA, and TLK were regarded as primary results, and the others were secondary outcomes. The independent sample t‐test was used to compare gender. Pearson correlation analysis was used to evaluate the correlation between primary results and secondary results. We take PI‐LL, PT, SVA, and TLK as dependent variables and include relevant factors for analysis.

Results

In the case of gender, PI, PI‐LL, and PT were found smaller in men than women, but TK is greater in men than women (27.3° ± 6.1° vs 23.3° ± 7.7°, p = 0.033). PI‐LL was positively correlated with PT (r = 0.608, p < 0.001) and negatively correlated with HIA (r = −0.193, p = 0.010); PT was negatively correlated with HIA (r = −0.289, p < 0.01). As to the relationship between primary and secondary results, HIA was positively correlated with SS and PR (p < 0.01). SVA was positively correlated with SSA (r = 0.341, p = 0.010). The positive influencing factors and risk factors of SVA were SSA, and PI‐LL played a negative regulatory role through proximal TK, the distal PT plays a positive regulatory role. The regulation of PI‐LL was compensated through both TK and PT, with a fitting relationship of PI‐LL = 0.5 × PT − 0.2 × TK.

Conclusion

There was a close interaction among spine‐pelvic‐hip sagittal parameters. We found the matching of PI‐LL in the domestic middle‐aged and elderly LSS population is regulated by thoracic spine and pelvis.

Effects of Postural Interventions on Physical and Psychological Aspects of Children in Terms of Secondary Sexual Characteristics

Children with secondary sexual characteristics who experience considerable physical, psychological, and social development are prone to physical and mental imbalances. The effects of postural intervention on physical and psychological aspects in junior high school students in terms of secondary sexual characteristics were investigated in this study. Of the 30 participants in this study, 21 (10 boys, 11 girls) with complete measurements were included. The postural intervention consisted of 1 month of direct muscle stretching for postural maintenance and breathing as well as activities to orient the spinal curvature. The participants’ body arrangement, spinal curvature, and General Health Questionnaire 30 (GHQ) scores were compared before and after the postural intervention. The intervention improved postural alignment (e.g., head−neck angle t20 = 2.33, p < 0.05, 95%CI [0.30, 5.36]) and GHQ scores (e.g., GHQ total t20 = 3.36, p < 0.01, 95%CI [0.79, 3.40]). The postural intervention improved the posture of the students as well as positively affected their mental health. This study showed that students with secondary sexual characteristics can receive physical and psychological care without the use of special facilities or techniques.

Psychometric Properties of the Scoliosis Research Society Questionnaire (Version 22r) Domains Among Adults With Spinal Deformity: A Rasch Measurement Theory Analysis

Objective

Adult spinal deformity (ASD) have lower health-related quality of life (HRQoL) compared to the general population. Applying Rasch measurement theory (RMT), this study tested the revised Scoliosis Research Society-22 (SRS-22r) HRQoL instrument among symptomatic adult patients with degenerative spinal disorders and varying degrees of ASD.

Methods

SRS-22r data from 637 outpatient spine clinic patients with degenerative spine conditions were investigated for unidimensionality, item/scale fit, differential item functioning (DIF), scale coverage/targeting, and person separation index (PSI) using RMT.

Results

Unidimensionality of the SRS-22r was not supported for either the total score or for 3 of its 5 domains. Item fit was acceptable for 11/22 items. The individual domains showed good coverage despite the degree of structural disorders. Ordered thresholds were achieved by merging response categories in some of the items. DIF towards age or sex was found in 11/22 items and in some domain items. The PSI exceeded 0.7 for the SRS-22r total score.

Conclusion

The individual domain scores of the SRS-22r perform better than the total score providing good coverage and targeting among patients with ASD. Refinements of items and domains may improve the structural validity of the instrument to meet the criteria for measuring ASD patients, even when multidimensionality persists.

The Short-Term Changes of the Sagittal Spinal Alignments After Acute Vertebral Compression Fracture Receiving Vertebroplasty and Their Relationship With the Change of Bathel Index in the Elderly

Introduction

Fragility vertebral compression fractures (VCFs) are of major concern due to aging populations worldwide, which may occur after a fall from standing or due to severe osteoporosis, impacting greatly the life quality of the elderly. This study thus determined the factors independently associated with poor functional recovery from a new VCF and changes in sagittal spinal alignment after vertebroplasty in elderly patients with osteoporosis.

Materials and Methods

The data were collected from patients older than 70 years and diagnosed with a new VCF. Logistic regression analysis was performed to determine factors independently associated with function and radiographic status.

Results

We enrolled 8 male and 34 female patients with a mean age of 80.74 ± 8.31 years between January and July 2020. Compared with preoperative data, post-vertebroplasty lumbar sagittal alignments and functional scores improved significantly, and function recovered gradually over 12 weeks. Climbing stairs was the most influential performance indicator at the beginning of the recovery process. At each postoperative follow-up, changes in the C7-sacrum sagittal vertical axis exhibited an influence on functional recovery. Male patients were better able to move from a chair to a bed at the 2-week postoperative follow-up, and positive changes in the spino-sacral angle led to improved function in terms of stair climbing at the 6-week postoperative follow-up.

Conclusions

Vertebroplasty seemed to be effective for functional recovery related to sagittal spinal alignment improvement of the elderly with VCFs during postoperative 12 weeks, which may be a critical stage for the recovery for their life activities. The recovery rate for stair climbing after vertebroplasty was slower than for the other functional performance indicators in our study. In addition, if a patient was unable to demonstrate a marked improvement in sagittal alignment, they were likely to have ongoing impaired function and a poor prognosis after surgery.

Correlation Between Different Sagittal Parameters in Patients With Degenerative Kyphosis

Objective

To explore the relationship between different sagittal parameters and identify the fitting formula of spino-pelvic parameters in patients with degenerative kyphosis (DK).

Summary of Background

Sagittal balance is increasingly recognized as a predictor of clinical outcomes in patients with DK, while the relationship between different sagittal parameters in patients with DK remains unidentified.

Methods

A retrospective study with 279 participants was conducted. There were 168 DK patients which were divided into a sagittal balance group (SB:52 cases) and sagittal imbalance (SIB:116 cases). Radiographic measurements included thoracolumbar kyphosis (TLK), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), and pelvic tilt (PT). The correlations were analyzed between different sagittal parameters.

Results

There were significant differences between the SB and SIB groups in terms of TLK, LL, PI-LL, PT, SVA, sacral slope (SS), and TK. For patients with DK, the LL was correlated with PT and TK. The linear regression was LL = 22.76−0.28 × PT + 0.62 × TK. In the SB group, TK was the influencing factor for LL and the linear regression analysis showed that LL = 33.57 + 0.33 × TK. While in the SIB group, PT and TK were in synergistic effect with PI-LL, the linear regression analysis showed that LL = 22.76−0.28 × PT + 0.62 × TK.

Conclusion

From the present study, we can see that LL has a significant correlation with PT and TK in patients with DK, while in SB, the LL was only correlated with TK. Therefore, the correction of LL in a different group should be calculated to avoid the incidence of proximal junction kyphosis (PJK).

Comparison of Percutaneous Kyphoplasty With or Without Posterior Pedicle Screw Fixation on Spinal Sagittal Balance in Elderly Patients With Severe Osteoporotic Vertebral Compression Fracture: A Retrospective Study

Objective

To compare the effects of percutaneous kyphoplasty (PKP) with or without posterior pedicle screw fixation (PPSF) on spinal sagittal balance in elderly patients with severe osteoporotic vertebral compression fracture (sOVCF).

Methods

From January 2016 to December 2018, 102 elderly patients with single-level thoracolumbar sOVCF were enrolled. Among them, 78 cases underwent PKP (Group A), and 24 cases underwent PPSF+KP (Group B). Clinical evaluation included perioperative parameters, Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back pain; Radiographic evaluation included anterior vertebral height (AVH) and rate (AVHr), local kyphotic angle (LKA), and spino-pelvic sagittal balance parameters.

Results

Perioperative parameters including operation time, blood loss, fluoroscopic time and hospital stay in Group A were less than those in Group B (p &lt; 0.05). Compared with the pre-operative results, the ODI and VAS scores of both groups decreased significantly in the three follow-ups after surgery (p &lt; 0.05). The post-operative ODI and VAS scores of Group A were significantly better than those of Group B, but the results were opposite at the final follow-up (p &lt; 0.05). Compared with the pre-operative values, except that there was no significant difference in pelvic incidence (PI) (p &gt; 0.05), other radiographic parameters of both groups were improved significantly in the three follow-ups after surgery (p &lt; 0.05). The AVH, AVHr, LKA and lumbar lordosis (LL) in Group B were better than those in Group A in the three follow-ups after surgery (p &lt; 0.05). At the final follow-up, the sacral slope (SS) and pelvic tilt (PT) differed significantly between the two groups (p &lt; 0.05).

Conclusions

Both PPSF+KP and PKP can achieve favorable clinical outcomes and maintain the spinal sagittal balance. Compared with PPSF+KP, PKP showed more significant advantages in the early post-operative period. However, in the long-term follow-up, PPSF+KP showed better clinical outcomes and may be better than PKP in maintaining spinal sagittal balance.

Sagittal imbalance of the spine is associated with poor sitting posture among primary and secondary school students in China: a cross-sectional study

Background

Long-term poor posture may affect the morphological development of the spine. However, there is no definite answer as to how writing posture affects students’ spine. This study attempted to compare the sagittal curvature of the spine between sitting and standing postures in adolescents to reveal the variation rule of spinal sagittal curvature of students with learning posture, and to discover the key factors that may affect students’ spinal health.

Methods

1138 participants (male, 604; female, 534; age range, 6–18 years) from three schools in Tianjin, China, including 570 primary school students and 568 secondary school students. This study used SpineScan and PA200 Station Posture Assessment System to assess the sagittal curvature of the spine for three postures: sitting on a chair in upright position, seated at a desk while reading/writing, and standing in natural relaxed position. Analyze the difference between spine angle of the three postures and the correlation between the sagittal plane angle of the spine and body posture.

Results

The mean sagittal angle of the spine changed when the participants were in reading/writing position compared to standing position, with the lumbar lordosis angle significantly decreased (p < 0.05) and the thoracic kyphosis angle significantly increased (p < 0.05). The TKA and LLA angles were abnormal in 33 and 52% of students in reading/writing posture respectively. There was a significant correlation between sitting posture and standing spinal Angle and were positively correlated with the height of the teenager (p < 0.05). By contrast, a higher percentage of TKA and LLA subjects in the standard reading/writing posture reference range maintained normal spinal shape while standing.

Conclusions

The angle of thoracic kyphosis significantly increased from standing posture to upright sitting, reading/writing posture, while lumbar lordosis significantly decreased or even disappeared. There was a significant correlation between sagittal angle of spine in different postures. The poor sitting posture associated with sagittal angle abnormalities impact the shape of the spine such that sagittal imbalance was also observed when students in natural standing posture. Height is an important factor affecting the sitting spine shape of students.

Correlation and Differences in Lumbopelvic Sagittal Alignment Parameters Between Lumbar Radiographs and Magnetic Resonance Images

STUDY DESIGN

Imaging parameter study.

OBJECTIVE

Though lumbar alignment is better evaluated using standing radiograph than supine magnetic resonance imaging (MRI), few studies have researched this. Our study aimed to observe the correlation and difference in alignment between standing radiograph and supine MRI, and assess whether the change of position affects the lumbopelvic parameters.

METHODS

We analyzed 105 patients, measuring lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). Inter- and intraparameter analyses were performed to identify any difference between standing radiograph and supine MRI. Statistical differences between the lumbopelvic parameters were compared.

RESULTS

There was excellent interobserver agreement for each parameter (interclass correlation coefficient > 0.75), and significant differences were observed in each parameter between radiograph and MRI (P < .05). Strong correlations were noted between the equivalent parameters in radiograph and MRI, both SS and PI were strongly correlated with LL in radiograph and MRI image, both PT and SS were strongly correlated with PI in radiograph and MRI image (r = -1.0 to -0.5 or 0.5 to 1.0).

CONCLUSION

Supine MRI obviously underestimated the measurements of lumbopelvic sagittal alignment parameters in standing radiograph. Therefore, standing lumbar radiographs should be obtained preoperatively in all surgical patients, not only supine MRI. In addition, we observed that PI was not a constant morphological parameter.

Association between sagittal spinopelvic alignment and femoral head destruction in the early stage of rapidly destructive coxopathy

Aims

This study aimed to evaluate sagittal spinopelvic alignment (SSPA) in the early stage of rapidly destructive coxopathy (RDC) compared with hip osteoarthritis (HOA), and to identify risk factors of SSPA for destruction of the femoral head within 12 months after the disease onset.

Methods

This study enrolled 34 RDC patients with joint space narrowing > 2 mm within 12 months after the onset of hip pain and 25 HOA patients showing femoral head destruction. Sharp angle was measured for acetabular coverage evaluation. Femoral head collapse ratio was calculated for assessment of the extent of femoral head collapse by RDC. The following parameters of SSPA were evaluated using the whole spinopelvic radiograph: pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), sagittal vertical axis (SVA), thoracic kyphosis angle (TK), lumbar lordosis angle (LL), and PI-LL.

Results

The HOA group showed higher Sharp angles compared with the RDC group. PT and PI-LL were higher in the RDC group than the HOA group. SS and LL were lower in the RDC group than the HOA group. No difference was found in PI, SVA, or TK between the groups. Femoral head collapse ratio was associated with PT, SS, SVA, LL, and PI-LL. A PI-LL > 20° and a PT > 30° correlated with greater extent of femoral head destruction by RDC. From regression analysis, SS and SVA were significantly associated with the femoral head collapse ratio within 12 months after disease onset.

Conclusion

Compared with HOA, RDC in the early stage correlated with sagittal spinopelvic malalignment. SS and SVA may partially contribute to the extent of femoral head destruction by RDC within 12 months after the onset of hip pain. The present study indicates a potential role of SSPA assessment in identification of RDC patients at risk for subsequent bone destruction. Cite this article: Bone Jt Open 2022;3(1):77–84.

Perioperative Predictive Factors for Positive Outcomes in Spine Fusion for Adult Deformity Correction

Purpose: Identifying perioperative factors that may influence the outcomes of long spine fusion for the treatment of adult deformity is key for tailored surgical planning and targeted informed consent. The aim of this study was to analyze the association between demographic or perioperative factors and clinical outcomes 2 years after long spine fusion for the treatment of adult deformity. Methods: This study is a multivariate analysis of retrospectively collected data. All patients who underwent long fusion of the lumbar spine for adult spinal deformity (January 2016–June 2019) were included. The outcomes of interest were the Oswestry disability index (ODI), visual analogic scale (VAS) preoperatively and at 1 and 2 years’ follow up, age, body mass index, American Society of Anaesthesiologists (ASA) score, upper and lowest instrumented vertebrae (UIV and LIV, respectively), length of surgery, estimated blood loss, and length of hospital stay. Results: Data from 192 patients were available. The ODI at 2 years correlated weakly to moderately with age (r = 0.4), BMI (r = 0.2), ASA (r = 0.3), and LIV (r = 0.2), and strongly with preoperative ODI (r = 0.6). The leg VAS at 2 years moderately correlated with age (r = 0.3) and BMI (r = 0.3). Conclusion: ODI and VAS at 2 years’ follow-up had no to little association to preoperative age, health status, LIV, or other peroperative data, but showed a strong correlation with preoperative ODI and pain level.

Postoperative alterations of sagittal cervical alignment and risk factors for cervical kyphosis in 124 Lenke 1 adolescent idiopathic scoliosis patients

BACKGROUND

This study aims to analyze postoperative changes of cervical sagittal curvature and to identify independent risk factors for cervical kyphosis in Lenke type 1 adolescent idiopathic scoliosis (AIS) patients.

METHODS

A total of 124 AIS patients who received all-pedicle-screw instrumentation were enrolled. All patients were followed up for at least 2 years. The following parameters were measured preoperatively, immediately after the operation, and at the last follow-up: pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), global thoracic kyphosis (GTK), proximal thoracic kyphosis (PrTK), T1-slope, cervical lordosis (CL), McGregor slope (McGS), sagittal vertical axis (SVA), C2-7 SVA (cSVA), and main thoracic angle (MTA). Statistical analysis was performed to evaluate postoperative alterations of and correlations between the parameters and to identify risk factors for cervical kyphosis. Statistical significance was set at P < 0.05.

RESULTS

After the operation, PrTK and T1-slope significantly increased (3.01 ± 11.46, 3.8 ± 10.76, respectively), cervical lordosis improved with an insignificant increase (- 2.11 ± 13.47, P = 0.154), and MTA, SS, and LL decreased significantly (- 33.68 ± 15.35, - 2.98 ± 8.41, 2.82 ± 9.92, respectively). Intergroup comparison and logistic regression revealed that preoperative CK > 2.35° and immediate postoperative GTK < 27.15° were independent risk factors for final cervical kyphosis, and △T1-slope < 4.8° for a kyphotic trend.

CONCLUSIONS

Postoperative restoration of thoracic kyphosis, especially proximal thoracic kyphosis, and T1-slope play a central role in cervical sagittal compensation. Preoperative CK, postoperative small GTK, and insufficient △T1-slope are all independent risk factors for cervical decompensation.