Retrospective study.

To determine the ideal pelvic incidence (PI)-lumbar lordosis (LL) range to prevent pelvic tilt (PT) undercorrection while avoiding PI-LL overcorrection following adult spinal deformity (ASD) surgery.

PI-LL and PT are the important sagittal parameters to be restored to an adequate range by surgery. Ideal PI-LL target without causing PI-LL overcorrection and PT undercorrection has not been documented.

We included patients with ASD undergoing ≥5-level fusion, including the sacrum. Receiver operating characteristic (ROC) curve analysis was performed to calculate the lower limit of the ideal PI-LL without causing PI-LL overcorrection and the upper limit of the ideal PI-LL without causing PT undercorrection. The calculated ideal PI-LL was validated in terms of proximal junctional kyphosis and failure (PJK and PJF) rates and clinical outcomes. Analyses were performed according to age subgroups (below 70 and 70 yr or above).

In total, 426 patients were included in the study. Female patients were predominant (85.4%), with a mean age of 69.8 years. The lower limits of PI-LL were calculated as 4.9° for all patients, 2.3° for patients aged below 70 years, and 7.9° for patients aged 70 years or above. Meanwhile, the upper limits of PI-LL were calculated as 12.7° for all patients, 12.5° for patients aged below 70 years, and 13.3° for patients aged 70 years or above. There were no significant differences in the PJK and PJF rates among the new three PI-LL groups. Clinical outcomes were significantly better in patients with the ideal PI-LL group than those in patients with overcorrection or undercorrection groups for all age groups.

The ideal PI-LL correction target without adversely impacting PT and PI-LL was calculated at 2.3° to 12.5° for patients aged below 70 years and 7.9° to 13.3° for patients aged 70 years or above. These guideline parameters may help ensure optimal clinical outcomes without increasing the risk of PJK/F.

To evaluate the effect of the lower extremities on cone of economy (CoE) calculations as well as to propose a novel assessment of seated balance using traditional CoE measurements.

36 controls and 82 degenerative lumbar disease (LD) patients, (38 patients with unilateral radiculopathy (UR), 44 patients with neurogenic claudication (NC) with bilateral symptoms), were enrolled in the study. Functional balance tests were performed and recorded by 3D motion capture in both the standing (Romberg) and seated positions. Balance effort and CoE dimensions were calculated.

The lower extremities exert a significant impact on balance, as reflected in the total head (UR: 20.9, NC: 31.5 vs. H: 10.0 cm, p < 0.015), pelvis (UR: 73.2, NC: 110.0 vs. H: 36.4 cm, p < 0.002) and CoM (UR: 17.1, NC: 18.7 vs. H: 4.6 cm, p < 0.001) sway differences observed between LD patients and healthy controls. Significant differences in CoE dimensions were observed as captured by sagittal head (UR: 2.8 vs. H: 0.9 cm, p = 0.014) and pelvis (UR: 2.8 vs. H: 1.4 cm, p = 0.019) range of sway (RoS) and coronal pelvic RoS (UR: 1.1, NC: 1.1 vs. H: 0.6 cm, p < 0.012) between LD patients and healthy controls.

This study first provides a novel standardized means of isolating and quantifying the role of the lower extremity on the CoE in patients with LD, which highlights how spinal pathologies may directly impact and/or contribute to compensatory mechanisms in this region. As evidenced by 18.0-93.2 cm of total sway and 1.1-2.8 cm RoS, the lower extremities account for a significant amount of balance effort and CoE dimensions.

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional spinal deformity where sagittal alignment significantly influences clinical outcomes. This study aims to analyze spinopelvic balance parameters in asymptomatic adolescents without scoliosis, examining the correlation between pelvic coronal parameters and sagittal balance parameters to validate their use as preliminary indicators in assessing pelvic rotation.

A prospective study was conducted involving 354 adolescents (199 females, 155 males) aged 6-18 years who underwent full-length anteroposterior (AP) and lateral spine radiographs at The Third Hospital of Hebei Medical University between October 2022 and December 2023. Ethical approval and informed consent were obtained. Radiographic assessments included measuring pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), pelvic sacral angle (PSA), and other related parameters. Statistical analysis was performed using SPSS software.

Significant gender differences were observed in Risser sign distribution and pelvic tilt, with females exhibiting more advanced skeletal maturity. Positive correlations were found between pelvic incidence and pelvic tilt (r = 0.41), and pelvic incidence and sacral slope (r = 0.57), while negative correlations were noted between pelvic incidence and pelvic sacral angle (r = -0.43). Strong correlations between sagittal parameters and newly introduced coronal parameters, such as sacral-femoral-pubic angle and Pubo-Hilgenreiner Distance, were also identified.

The study demonstrates that parameters like Iliac tilt, Pelvic sacral angle, Sacral-femoral-pubic angle, and Pubo-Hilgenreiner Distance correlate well with traditional spinopelvic parameters and can be used to assess pelvic sagittal balance in clinical settings. Future research should focus on longitudinal studies to further validate these findings.

Adjacent segment disease (ASDis) and degeneration (ASDeg) are common complications following lumbar fusion, ranging from asymptomatic radiographic changes to debilitating symptoms requiring revision surgery. While the impact of spinopelvic alignment (SPA) on postoperative outcomes and ASDis prevention is well-studied in long-construct fusions, its role in short-segment lumbosacral fusions, particularly over the long term, remains unclear.

This study aimed to investigate the association between global and distal lumbar SPA with the development of ASDis and ASDeg in the long-term follow-up of patients undergoing short-segment lumbosacral fusion. Secondary outcomes were patient reported outcome measures (PROMs) in relation to adjacent segment changes.

Retrospective single-center cohort study with minimum follow-up of 5 years.

A total of 86 patients who underwent L4-S1 spinal fusion between 2003 and 2015, with a mean follow-up of 12±4 years.

The primary outcome was the development of adjacent segment changes, classified into 2 groups: (1) surgically-treated ASDis, and (2) ASDeg, defined as radiographic evidence of adjacent segment changes without surgical intervention. Secondary outcomes included PROMs: the Oswestry Disability Index (ODI) and the European Quality of Life 5 Dimensions 5 Level (EQ5D5L).

Pre- and postoperative standing radiographs were annotated and the following global lumbar SPA parameters analyzed: Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), PI-LL-mismatch, lumbar pelvic angle (LPA). Additionally, the following distal lumbar SPA parameters were analyzed: Distal lordosis (DL) between L4-S1, lordosis distribution index (LDI=DL/LL), PI-DL-difference, DL-PI-ratio, adjacent segment lordosis (ASL). Postoperative ODI and EQ5D5L were assessed via a telephone interview.

Among 86 patients with a mean follow-up of 12±4 years the incidence of ASDis was 27.9% (n=24), while 7.0% (n=6) showed ASDeg. No significant differences in pre- and postoperative global lumbar SPA were found in patients who developed ASDis or ASDeg compared to patients who did not. PI (53.6° vs. 59.6°) and preoperative SS (34.9° vs. 40.3°) trended to be lower in the ASDis group compared to controls, although non-significant. Pre- and postoperative distal lumbar SPA parameters did not differ between groups. Patients with adjacent segment changes, regardless of whether they underwent revision surgery, reported worse PROMs. ODI scores were elevated in both the ASDis group (28, IQR 15-42) and the ASDeg group (34, IQR 14-47) compared to controls (10, IQR 2-24; p=.005). EQ5D5L scores were lower in both the ASDis (70, IQR 53-83) and the ASDeg groups (60, IQR 55-85) compared to controls (85, IQR 75-90; p=.025).

In this long-term follow-up study of patients undergoing short-segment lumbosacral fusion, neither preoperative nor postoperative SPA was significantly associated with the development of ASDis or ASDeg. These findings suggest that other factors may have a greater influence on ASDis risk. Patients who developed adjacent segment changes, whether or not they required revision surgery, experienced worse long-term postoperative PROMs, indicating the importance of ASDis prevention.

Study DesignRetrospective quantitative analysis study.ObjectivesPelvic incidence has been established as central radiographic marker which determines patient-specific correction goals during surgery for adult spinal deformity. In cases with sacral doming or sacral osteotomy where the PI cannot be calculated, reliable radiographic parameters need to be established to determine surgical goals. We aim to determine multiple radiographic parameters and formulas that can be utilized when the S1 superior endplate is obscured.MethodsRetrospective analysis was performed on 68 healthy volunteers without prior spine surgery with full-length radiographs. Pelvic incidence, sacral slope, and pelvic tilt were calculated for each patient. Additional measurements such as L4, L5, and S2 incidence, tilt, and slope were collected. A new radiographic parameter defined as the L4-Sciatic notch angle was measured. Regression analysis was performed on each value to determine its relationship with S1 based incidence, tilt, and slope.ResultsMean values for L5 incidence, L4 incidence, and L4 sciatic notch angle were 21.8° ± 8.9, 4.4° ± 8.1, and 44.4° ± 12, respectively. The linear regression analysis produced the following formulas which can be utilized to determine deformity correction goals when pelvic incidence can be calculated pre-operatively: L5i = .65*S1i-11.4, L4i = .44*S1i-18.6, and L4SNA = -.34*S1i + 66.5. In settings where pelvic incidence cannot be calculated, the following formulas can be utilized: L5i = .66*S2i-32.3 and L4SNA = -.02*S2i2 + 1.1*S2i + 63.5. P-values for all regression analyses were <.001.ConclusionThis study provides target radiographic alignment values that can be utilized for patients with either pre-operative altered S1 endplates or in cases with intraoperative alteration of S1 (sacral osteotomy).

Study designRetrospective analysis.ObjectivesTo assess the role of paraspinal muscle morphology in predicting complications after adult spinal deformity (ASD) surgery.Materials and MethodsA total of 93 patients who underwent surgery for ASD from 2017 to 2022 were enrolled. Using early postoperative X-ray, they were divided into proportioned (P), moderately proportioned (MP), and severely proportioned (DP) groups based on the Global Alignment and Proportion (GAP) scores. Further, they were classified into two groups: Group A (presence of mechanical complications) and Group B (no mechanical complications). In addition, other parameters including preoperative BMI, smoking status, cross-sectional area (CSA), and grades of paraspinal muscle fatty infiltration (FI) were calculated in all patients using preoperative MRI. These parameters were compared across the groups using a one-way analysis of variance (ANOVA). Post-hoc pairwise testing was done using Bonferroni's method. These were also compared between groups A and B using a 2-sample t-test.ResultsThe mean follow-up period was 32.7 months (24-64 months). 27 (29%) of 93 patients developed mechanical complications following ASD surgery. Of the 27 patients, 6 (22.2%) were proportioned, 10 (37%) were from MP and 11 (40.7%) were from the DP group. Group A had low CSA (P = 0.014), and high FI (P = 0.003) grades compared to group B. Further, 22.2% (6/27) had a history of smoking before surgery (OR = 6.57).ConclusionsWe recommend consideration of preoperative smoking, CSA, and FI of paraspinal muscles in addition to the GAP score to minimize mechanical complications in patients undergoing ASD surgery.

Adult spinal deformity (ASD) is a spectrum of abnormalities of the thoracic and lumbar spine and has an increasing prevalence. It is associated with significant physical and mental disability in symptomatic patients. Given the increased rates and the morbidity associated with this disease, novel innovation in the diagnosis and treatment of such deformity is required. The SRS-Schwab classification system described coronal scoliotic deformity with sagittal modifiers. Other parameters, such as the sagittal vertical axis, pelvic tilt, T1 pelvic angle, pelvic incidence and lumbar lordosis attempted to quantify global sagittal balance. More recently, a focus on more patient specific parameters has been targeted to improve patient outcomes. The Roussouly classification system attempted to predict sagittal alignment parameters based on fixed parameters of the pelvis. Others determined the parameters based on patient age. Technological advances have also enhanced our understanding of ASD. Long cassette films and automated analyses have allowed standardization of these measurements across physicians. 3D printing has been used as an adjunct for both surgical planning and implants, both generic and patient specific, to improve outcomes. With these, advances in minimally invasive approaches have allowed ASD correction with lower complications and blood loss. Intraoperative navigation and the use of robotics has allowed improved accuracy in the care of these patients. Development of complex osteotomies have allowed for correction of advanced deformity. Fusion, however, is the ultimate goal of surgical ASD correction. Advances in biologics such as the use of recombinant Human Bone Morphogenetic Protein-2 have been used to improve fusion rates and combat pseudoarthrosis. Finally, post-operative advances in ASD patient care with emphasis on enhanced recovery after surgery has allowed improvements in hospital length of stay and pain scores. ASD is becoming a more ubiquitous diagnosis for spine surgeons with an increasing aging population. Improvement in the understanding of the diagnosis, spinopelvic parameters, imaging techniques, and post operative care are all aimed toward helping patients in whom care can be extremely difficult. Further study in ASD patient care will target advanced innovation to provide optimal treatment to these patients and allow for best possible outcomes.

Vascular injuries during anterior lumbar interbody fusion (ALIF) are reported in the existing literature with an incidence rate ranging from 1% to 24%, predominantly venous lacerations owing to branch vessel avulsions during mobilization and retraction. Arterial injuries, although less frequent, occur at an incidence of 0.45% to 1.5% and are mainly characterized by thromboses; aortic lacerations remain exceptionally rare. L4-L5 and L5-S1 are the two levels associated with the majority of vascular complications. Preoperative 3D CT angiography is paramount and a gold standard, as it illustrates the anatomic variations of the iliolumbar vein, the aorta, and the vena cava bifurcation, providing the surgeon with valuable information regarding operative trajectories. Regarding preventive measures, venous laceration, the most common vascular injury, occurs less frequently when employing nonthreaded interbody grafts such as iliac crest autograft or femoral ring allograft. Also, left iliac artery thrombosis can be decreased intraoperatively by intermittent release of retraction. Managing vascular complications includes compression for bleeding control, Trendeleburg positioning of the patient and venorrhaphy, and the employment of topical clot-forming enhancement and/or hemostatic agents. Although postoperative lower limb duplex ultrasonography can be an effective tool, magnetic resonance venography (MRV) and intravenous catheterization (IVC) remain the gold standards for diagnosing postoperative pelvic vein thrombosis in cases of iliac vein repair after anterior spine surgery. This paper aimed to highlight the incidence of major vascular injury during ALIF surgery, describe predisposing risk factors, and discuss management techniques while highlighting the requirement for more sensitive and factor-specific studies to attain a more profound understanding of the mechanism of vasculature complications during ALIF procedures.

Reliability analysis.

Vertebral pelvic angles (VPA) are gaining popularity given their ability to describe the shape of the spine. Understanding the reliability and minimal detectable change (MDC) is necessary to determine how these measurement tools should be used in the manual assessment of spine radiographs. Our aim is to assess intra- and interobserver intraclass correlation coefficients (ICC) and the MDC in the use of VPA for assessing alignment in adult spinal deformity (ASD).

Three independent examiners blindly measured T1, T4, T9, L1, and L4PA twice in ASD patients with a 4-week window after the initial measurements. Patients who had undergone hip or shoulder arthroplasty, fused or transitional vertebrae, or whose hip joints were not visible on radiographs were excluded. Power analysis calculated a minimum sample size of 19. Both intra- and interobserver ICC and MDC, which denotes the smallest detectable change in a true value with 95% confidence, were calculated.

Out of the 193 patients, 39 were ultimately included in the study, and 390 measurements were performed by 3 raters. Intraobserver ICC values ranged from .90 to .99. The interobserver ICC was .97, .97, .96, .95, and .92, and the MDC was 5.3°, 5.1°, 4.8°, 4.9°, and 4.1° for T1, T4, T9, L1, and L4PA, respectively.

All VPAs showed excellent intra- and interobserver reliability, however, the MDC is relatively high compared to typical ranges for VPA values. Therefore, surgeons must be aware that substantial alignment changes may not be detected by a single VPA.

Retrospective review.

We sought to characterize complications associated with anterior column release (ACR).

Correction of positive sagittal imbalance was traditionally completed with anterior column grafts or posterior osteotomies. ACR is a minimally invasive technique for addressing sagittal plane deformity by restoring lumbar lordosis.

We conducted a retrospective review of consecutive patients who underwent ACR in a prospectively kept database at a tertiary care academic center from January 2012 to December 2018. The prespecified complications were hardware failure (rod fracture, hardware loosening, or screw fracture), proximal junctional kyphosis, ipsilateral thigh numbness, ipsilateral femoral nerve weakness, arterial injury requiring blood transfusion, bowel injury, and abdominal pseudohernia.

Thirty-eight patients were identified. Thirty-five patients had ACR at L3-4, 1 had ACR at L4-5, and 1 patient had ACR at L2-3 and L3-4. Eighteen patients (47.4%) had one of the prespecified complications (10 patients had multiple). Ten patients developed hardware failure (26.3%); 8 patients (21.1%) had rod fracture, 4 (10.5%) had screw fracture, and 1 (2.6%) had screw loosening. At discharge, rates of ipsilateral thigh numbness (37.8%) and hip flexor (37.8%)/quadriceps weakness (29.7%) were the highest. At follow-up, 6 patients (16.2%) had ipsilateral anterolateral thigh numbness, 5 (13.5%) suffered from ipsilateral hip flexion weakness, and 3 patients (5.4%) from ipsilateral quadriceps weakness. Arterial injury occurred in 1 patient (2.7%). Abdominal pseudohernia occurred in 1 patient (2.7%). There were no bowel injuries observed.

ACR is associated with a higher than initially anticipated risk of neurological complications, hardware failure, and proximal junctional kyphosis.

The effect of skeletal muscle mass of the trunk and extremities on sagittal imbalance of the spine before and after surgery for adult spinal deformity (ASD) has not been elucidated. The purpose of this study was to examine the correlation between reduced skeletal muscle mass of the trunk and extremities, as well as spinopelvic parameters, preoperatively, postoperatively and at least 2 years after surgery for ASD.

This retrospective observational study included 140 consecutive patients who had undergone surgery for ASD and were followed-up for at least 2 years and whose skeletal muscle mass could be measured preoperatively using whole-body dual-energy X-ray absorptiometry. Correlations between skeletal muscle mass and spinopelvic parameters were assessed preoperatively, postoperatively, and after 2 years of follow-up.

All spinopelvic parameters were significantly improved postoperatively compared with preoperatively. Between the postoperative period and two years post-surgery, a significant loss of correction was observed in SVA and GT. Trunk muscles mass showed significant negative correlations with preoperative PT, SS, PI-LL, SVA, GT, and TPA, but there was no significant correlation with postoperative parameters. Through univariate and multivariate regression analysis, lower limb skeletal muscle mass showed a significant negative correlation with SVA at two years postoperatively and the loss of corrected SVA (ΔSVA) over two years.

This study revealed that lower extremity muscle mass was implicated in the loss of corrected SVA 2 years after surgery. This study is clinically meaningful as it suggests that strength training for the lower extremities, performed preoperatively and/or postoperatively, can improve sagittal imbalances of the spine in patients with severe ASD or maintain SVA after corrective surgery.

Retrospective review of prospective multicenter data.

This study aimed to investigate the shape of TK before and after fusion in ASD patients treated with long fusion.

ASD patients undergoing posterior spinal fusions including at least T5 to L1 without prior fusion extending to the thoracic spine were included. Patients were categorized based on the preoperative T1-T12 kyphosis into: Hypo-TK (if < 30°), Normal-TK, and Hyper-TK (if > 70°). Regional kyphosis at T10-L1 (Distal), T5-T10 (Middle), and T1-T5 (Proximal) and their relative contributions to total kyphosis were compared between groups, and the pre-to postoperative changes were investigated using paired t test.

In total, 329 patients were included in this analysis (mean age: 57 ± 16 years, 79.6% female). Preoperative T1-T12 TK for the entire cohort was 40.9 ± 2° (32% Hypo-TK, 11% Hyper-TK, 57% Normal-TK). The Hypo-TK group had the smallest distal TK (5.9 vs 17.1 & 26.0), and middle TK (8.0 vs 25.3 & 45.4), but the percentage of contribution to total kyphosis was not significantly different (Distal: 24.1% vs 34.1% vs 32.8%; Middle: 46.6% vs 53.9% vs 56.8%, all P > .1). Postoperatively, T1-12 TK increased significantly (40.9 ± 2.0° vs 57.8 ± 17.6°). Each group had a decrease in distal kyphosis (Hypo-TK 2.6 ± 10.4°; Normal-TK 8.9 ± 11.5°; Hyper-TK 14.9 ± 12°, all P < .05). The middle kyphosis significantly decreased for Hyper-TK (11.8 ± 12.4) and increased for both Normal-TK and Hypo-TK (3.8 ± 11° and 14.2 ± 11°). Proximal TK increased significantly for all groups by 14-18°. Deterioration from Normal-TK to Hyper-TK postoperatively was associated with lower rate of patient satisfaction (59.6% vs 77.3%, P = .032).

Posterior spinal fusion for ASD alters the magnitude and shape of thoracic kyphosis. While 60% of patients had a normal TK at baseline, 30% of those patients developed iatrogenic hyperkyphosis postoperatively. Patients with baseline hypokyphosis were more likely to be corrected to normal TK than hyperkyphotic patients. Future research should investigate TK restoration in ASD and its impact on clinical outcomes and complications.

The sagittal alignment of the cervical spine and its relationship with spinopelvic parameters plays a crucial role in maintaining overall postural balance. This study aims to provide normative values for these parameters in asymptomatic pediatric subjects, aiding in the enhancement of treatment and evaluation strategies for spinal deformities and disorders. Conducted at the Third Hospital of Hebei Medical University, this retrospective study included 307 asymptomatic pediatric volunteers aged 4-18 years, screened for scoliosis from January 2021 to July 2023. Participants underwent whole-length EOS examinations following a standard protocol. Radiographic measurements of cervical and spinopelvic parameters were taken, and statistical analyses were performed using SPSS software to assess variations by age and gender. Normative values for cervical sagittal and spinopelvic parameters were established, demonstrating significant differences based on age and sex. Key findings include a strong correlation between the C2-7 Cobb angle and T1 and C7 slopes, with an observed increase in cSVA particularly pronounced in boys. Age and gender significantly influenced the normative values of these parameters, suggesting the importance of considering these factors in pediatric spinal assessments. This study establishes crucial normative values for cervical and spinopelvic parameters in a large pediatric cohort, highlighting the influence of age and sex on spinal sagittal alignment. The findings underscore the necessity of tailoring spinal assessment approaches in pediatric populations to improve the clinical evaluation and management of spinal health, providing a foundational benchmark for future research in pediatric spinal deformities and disorders.

Objectives: The aim of this study was to compare the radiographic results, mechanical complications, and clinical outcomes between anterior and posterior lumbar interbody fusion at L5-S1 (ALIF51 and PLIF51 groups, respectively) using a matched cohort of patients undergoing long fusion for adult spinal deformity (ASD). Methods: Patients who underwent hybrid surgery of ≥5-level fusion to the pelvis with a minimum follow-up duration of 2 years were included. The baseline characteristics of the groups were controlled using a propensity score matching analysis. The radiographic results, mechanical complications such as proximal junctional kyphosis/failure and metal failure, and clinical outcomes were compared between the groups. Results: In total, 79 patients were assigned to each group with comparable baseline data, except for a higher frequency of anterior column realignment procedures in the PLIF51 group than in the ALIF51 group (49.4% vs. 31.6%). At the last follow-up, L5-S1 segmental lordosis (SL) was significantly greater in the ALIF51 group than in the PLIF51 group (12.1° vs. 7.3°, p < 0.001). The final C7-sagittal vertical axis (SVA) was significantly smaller in the ALIF51 group than in the PLIF51 group (25.4 mm vs. 35.5 mm, p = 0.032). However, other global sagittal parameters were comparable between the groups. The mechanical complication rates, including metal failure at L5-S1, and the final clinical outcomes were comparable between the groups. Conclusions: ALIF51 has modest advantages over PLIF51 in terms of better restoring L5-S1 SL and C7-SVA with avoiding more invasive procedures above the L5-S1 levels. Other sagittal parameters, mechanical complication rates, and clinical outcomes did not differ between the groups.

This study aims to investigate the impacts of failure of pelvic compensation (FPC), as determined by variations in spinopelvic alignment during the transition from the supine to the upright position, on surgical outcomes in patients with adult spinal deformity (ASD).

A total of 125 ASD patients who underwent posterior correction surgery with a minimum follow-up of two years were enrolled. Radiographic outcomes, including thoracic kyphosis, lumbar lordosis, sacral slope (SS), pelvic tilt (PT), pelvic incidence, T1-pelvic-angle and sagittal vertical axis (SVA), were measured on lateral whole-spine radiographs. Postoperative realignment was assessed using the sagittal age-adjusted score (SAAS). Patient-reported outcomes were collected through Scoliosis Research Society-22R (SRS-22R) questionnaire, alongside data on minimum clinically important difference (MCID) achievement. The incidence of proximal junctional kyphosis (PJK) following surgery was also recorded. Based on the calculated minimum detectable change of SS, FPC was defined as the change in SS of less than 3.9° between supine and upright positions. Patients were divided into the pelvic compensation (PC) cohort and the FPC cohort.

Eighty-eight patients were categorized into the PC cohort and 37 into the FPC cohort. Postoperatively, patients with FPC exhibited significantly lower PT (22.44° vs. 28.57°, p <.001) and higher SVA (57.49 mm vs. 32.57 mm, p =.008) than PC patients. Additionally, the SRS-22R subtotal score was lower in the FPC group (3.68 vs. 3.89, p =.035), and the proportion of MCID achievement in SRS-22R was significantly reduced (45.95% vs. 65.91%, p =.038). While the incidence of PJK was higher in FPC patients, this difference was not significant (40.54% vs. 29.55%, p =.232). Correcting to SAAS matching standard was associated with a reduced risk of PJK (OR 6.50, 95%CI 1.18-35.84) and increased likelihood of achieving MCID (OR 4.50, 95%CI 1.05-19.22) in ASD patients with FPC.

ASD patients with preoperative FPC are more likely to experience worse patient-reported outcomes and a higher incidence of mechanical complications following corrective surgery. To optimize surgical outcomes in these patients, individualized preoperative planning aligned with the SAAS criteria may be particularly beneficial.

Spinal, pelvic, and lower extremity alignment is crucial for maintaining a healthy body posture. However, with aging, this posture becomes challenging to maintain due to muscle weakness and skeletal degeneration. Osteoarthritis (OA) of the hip and knee can also lead to abnormal posture, known as hip-spine and knee-spine syndrome. Total knee arthroplasty (TKA) can help relieve pain and improve lower extremity alignment. This may also improve abnormal posture, such as in knee-hip-spine syndrome. However, the condition of the contralateral knee may affect this improvement. This study evaluated the effects of TKA on clinical outcomes and radiographic body posture.

Patients scheduled for primary one-sided TKA were divided into 2 groups: the unilateral group comprised patients who had contralateral knee OA conditions. The bilateral group included patients who had prior contralateral TKA. Knee range of motion, the Knee Injury and Osteoarthritis Outcome Score, radiographic lateral femorotibial angle, hip and knee flexion angles, and sagittal vertical axis while standing were measured 24 months after TKA.

Both groups showed improved knee extension, the Knee Injury and Osteoarthritis Outcome Score, and radiographical femorotibial angle and hip and knee flexion angles 24 months after TKA. The sagittal vertical axis also improved 6 months after TKA in both groups and was maintained in the bilateral group, while it deteriorated again in the unilateral group 24 months after TKA.

A TKA can improve abnormal body posture due to knee OA as in knee-hip-spine syndrome. However, the condition of a contralateral knee can affect TKA outcomes.

Level III; prospective case-control study.

The purpose of this retrospective cohort study was to compare the 2-year radiological outcome and revision rates in patients with adult spinal deformity treated with either pedicle subtraction osteotomy (PSO) or posterior lumbar interbody fusion (PLIF), when PLIF was used to improve sagittal balance.

In 2016, PLIF was introduced at our institution as an alternative method when restoring lumbar lordosis. We analyzed 2 cohorts of patients with adult spinal deformity undergoing either PSO in 2010-2015 or PLIF in 2016-2020, retrospectively. The rate of mechanical failure was analyzed using competing risk analysis.

We included 141 patients (111 PSO and 30 PLIF). After propensity score matching, 60 patients undergoing PSO and 30 patients undergoing PLIF were included. Baseline demographics were comparable between groups but radiographic parameters differed significantly on Sacral Slope; 23 ± 13 versus 28 ± 10, and segmental lordosis; 7 ± 14° versus. 14 ± 13° (P-value < 0.05) for PSO and PLIF, respectively. Postoperatively, PSO patients had a larger global lordosis; 54 ± 12 versus 48 ± 14 and segmental lordosis of 33 ± 10 versus 26 ± 10 (P-value < 0.05), than PLIF patients. Competing risk analysis showed a cumulative incidence of revision surgery of 38.3% (95% CI 28-43) versus 16.7 (95% CI 3-30), (P-value < 0.05) for PSO, and PLIF at 2-year follow-up.

A significantly lower revision rate was seen for patients undergoing PLIF compared with PSO at a 2-year follow-up. A satisfactory sagittal correction was obtained for both groups regardless of the procedure. Thus, PLIF could be a viable option in selected cases.

To assess the stability of odontoid parameters on flexion-extension motion and to validate the accuracy of the physiological cervical lordosis (CL) predictive formula across different cervical positions.

Standard cervical spine lateral radiographs in neutral, flexion, and extension positions were collected to measure odontoid incidence (OI), odontoid tilt (OT), C2 slope (C2S), CL, T1 slope (T1S), and T1S minus CL (T1S-CL). Friedman's test was used to assess the differences in parameters among the three cervical spine positions. The predictive performance of the formula CL = 0.36× OI - 0.67 × OT - 0.69 × T1S was assessed and validated using the Pearson correlation coefficient (r), coefficient of determination (R²), mean squared error (MSE), and mean absolute error (MAE).

No significant differences were found for OI and T1S among the three different cervical spine positions (p = 0.162 and p = 0.186, respectively). There was a strong, significant positive correlation between the predicted value and actual value of physiological CL at three cervical positions (neutral, flexion, and extension). The predictions for the neutral position were the most accurate, with statistical measures of r = 0.85 (p < 0.01), R²=0.82, MAE = 4.28, and MSE = 27.77.

OI is a stable and reliable anatomic parameter, not affected by cervical spine flexion-extension motion. OI can serve as a supplementary parameter for evaluating cervical sagittal balance and compensatory ability. The formula CL = 0.36×OI - 0.67×OT - 0.69×T1S provides the best predictions for physiological CL in the neutral position.

Retrospective cohort study.

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.

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.

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.

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.

Baseline severities of sagittal malalignment and degrees of pelvic compensation may affect postsurgical outcomes differently after adult spinal deformity (ASD) surgery, even if the patients achieved optimal correction of sagittal malalignment.

To investigate whether postsurgical outcomes vary according to baseline sagittal alignment and pelvic compensation status in patients achieving adequate correction relative to age-adjusted alignment target in ASD surgery.

Retrospective study PATIENT SAMPLE: Patients who underwent ≥ 5-level fusion to the pelvis for ASD; achieved matched correction relative to age-adjusted pelvic incidence (PI)-lumbar lordosis (LL); and completed ≥ 2-year follow-up.

Radiographic results, mechanical failures, and clinical outcomes METHODS: Patients were divided into three groups based on baseline sagittal vertical axis (SVA) and pelvic tilt (PT)/PI ratio (median value of PT/PI ratio = 0.61): Group A (SVA < 5 cm), Group B (SVA ≥ 5 cm and PT/PI ratio <0.61, and Group C (SVA ≥ 5 cm and PT/PI ratio ≥ 0.61). Radiographic results, mechanical failures, and clinical outcomes were compared among the three groups.

A total of 153 patients were included in the study. They were predominantly female (89.5%), with a mean age of 68.3 years. The mean follow-up duration was 49.0 months. There were 50 patients in group A (SVA < 5cm), 53 in group B (SVA ≥ 5cm and low PT/PI), and 50 in group C (SVA ≥ 5cm and high PT/PI). No significant differences were observed in all radiographic parameters at six weeks. At the last follow-up, the PI-LL was comparable among the three groups; however, the SVA was significantly greater in groups B and C than in group A (46.5mm and 46.9mm vs. 31.5mm, p=.039). The PT at the last follow-up was significantly lower in group B than in group A and C (22.4° vs. 26.0° and 28.2°, respectively, p=.001). The rates of mechanical failure and subsequent revision surgery and did not differ among the groups. The final clinical outcomes were comparable among the three groups.

This study revealed that patients in groups B and C were likely to have a suboptimal sagittal alignment status at the last follow-up compared with those in group A. Tailored approaches considering patient's baseline alignment and compensatory status are recommended to optimize the final sagittal alignment status.

Objective  To evaluate the correlation between a radiographic scale of lumbar degenerative disease and the Oswestry Disability Index (ODI). Methods  A cross-sectional study in which the ODI quality of life questionnaire and the radiographic parameters for the classification of lumbar degenerative disease into different grades were compared to try to establish a relationship between them. Results  The relationship between the radiographic parameters and quality of life indicators does not behave homogeneously, considering the different grades of the lumbar grading scale. Grade-2 lumbar degenerative disease showed a statistically significant relationship with the worsening of the ODI quality of life score. Conclusion  The lumbar degenerative disease grading scale used in the present study showed a relevant clinical potential, as it presented a significant relationship with the quality of life measured by the ODI score in part of the groups evaluated.

The Scoliosis Research Society (SRS)-Schwab system does not include a pelvic compensation (PC) subtype, potentially contributing to gaps in clinical characteristics and treatment strategy for deformity correction. It also remains uncertain as to whether PC has differing roles in sagittal balance (SB) or imbalance (SI) status. To compare radiological parameters and SRS-22r domains between patients with failed pelvic compensation (FPC) and successful pelvic compensation (SPC) based on preoperative SB and SI.

A total of 145 adult spinal deformity patients who received deformity correction were analyzed. Radiographic and clinical outcomes were collected for statistical analysis. Patients were classified into 4 groups based on the median value of PT/PI ratio (PTr) and the cutoff value of SB. Patients with low PTr and high PTr were defined as FPC and SPC, respectively. Radiographic and clinical characteristics of different groups were compared.

Patients with SPC exhibited significantly greater improvements in lumbar lordosis, pelvic tilt, PTr, and T1 pelvic angle as compared to patients with FPC, irrespective of SB or SI. No apparent differences in any of SRS-22r domains were observed at follow-up when comparing the SB-FPC and SB-SPC patients. However, patients with SI-SPC exhibited significantly better function, self-image, satisfaction, and subtotal domains at follow-up relative to those with SI-FPC. When SI-FPC and SI-SPC patients were subdivided further based on the degree of PI-LL by adjusting for age, the postoperative function and self-image domains were significantly better in the group with overcorrection of PI-LL than undercorrection of PI-LL in SI-FPC patients. However, no differences in these SRS-22r scores were observed when comparing the subgroups in SI-SPC patients.

Flexible pelvic rotation is associated with benefits to the correction of sagittal parameters, irrespective of preoperative SB or SI status. However, PC is only significantly associated with clinical outcomes under SI. Patients with SI-FPC exhibit poorer postoperative clinical outcomes, which should be recommended to minimize PI-LL.

With an aging population, degenerative spinal diseases are contributing significantly to the healthcare's burden. Spinal alignment in the context of adult spinal deformities has become an important domain of research.

We conducted a narrative review of the latest considerations in spinal alignment within the context of degenerative spinal conditions, discussed current strategies for morphological assessment and finally identified potential areas for future research.

This review reported that degenerative spinal conditions lead to a complex disruption of spinal alignment. It also highlighted the importance of spino-pelvic alignment with specific attention to compensatory mechanisms that occur in response to spinal deformities. Emerging technologies including Artificial Intelligence and epigenetics are showing promises in terms of patient care.

Understanding spinal alignment in degenerative conditions underscores the importance of dynamic and individualized assessments. Future research should integrate emerging technologies along with traditional clinical practices in order to optimize patient outcomes and minimize complications for patients suffering from degenerative spinal diseases.

Patients with adult spinal deformity (ASD) lean forward with their trunks when walking, even if they can remain upright during static standing. However, it remains unclear which part of the spinal column is involved in forward trunk tilt and the details of the relationships between sagittal alignment during static standing and changes in dynamic parameters during walking. Therefore, this study aimed to clarify the above by analyzing the walking motion of ASD patients using inertial measurement units (IMUs).

Preoperative ASD patients were included in this study. Dynamic parameters during gait were measured by IMUs attached on the skin at the T1, T12, and S1 spinous processes, thigh, and lower leg. Walking data were divided into three phases of 10 s each (initial, middle, and final), and the average dynamic parameters at each phase were statistically compared. The relationships between the standing radiographic and dynamic parameters in the final phase were evaluated by linear regression analyses.

A total of 34 patients were included in this study. Their mean age was 72 years. The inclination of IMUs on the T1, T12, and S1 and the flexion angle of T12-S1 IMUs significantly increased over time. Pelvic tilt (PT) of standing radiography was positively correlated with the inclination angles of T12 (r2=0.22, p=0.0048) and S1 (r2=0.16, p=0.0178) and the flexion angle of T12-S1 IMUs (r2=0.29, p=0.0011).

This study showed that anteversion of the trunk in patients with ASD is due to an increase in lumbar forward bending and anterior tilt of the pelvis. Lumbar forward bending was significantly correlated with PT on standing radiography. It is important to consider the presence of poorer posture during gait than during standing when we evaluate patients with high PT.

This study aimed to investigate the association between gait profile and spinal alignment in adolescent idiopathic scoliosis (AIS). The study group consisted of 80 AIS and 80 healthy controls. All participants underwent radiographic imaging and measured gait analysis. The gait profile included gait speed, step length, stance phase, cadence, single leg support, double legs support, gait asymmetry (GA), and phase coordination index (PCI). The spinal alignment parameters included pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), and coronal balance (CB). The mean age of the AIS group was 15.1 years, while the control group was 14.6 years. Significant differences were observed between the AIS patients and controls in gait speed, step length, stance phase, cadence, single leg support, double legs support, GA, PT, TK, SVA, and CB. However, no significant differences were found in PCI, SS, PI, and LL (p > 0.05). Additionally, correlation analysis revealed a close relationship between gait profile and spinal alignment parameters. Step length was significantly related to PT, SS, and LL, while GA was correlated with TK in AIS patients. Multiple regression analysis for predictors of step length found that PT and SS accurately predicted step length. First, the AIS group showed significant differences in gait kinematics and spinal alignment compared to the control group. Second, statistically significant correlations were found between gait profile and spinal alignment parameters. Specifically, PT and SS accurately predicted step length, and TK was correlated with GA in AIS patients.

As the population ages and technology advances, lateral lumbar intervertebral fusion (LLIF) is gaining popularity for the treatment of degenerative lumbar scoliosis (DLS). This study investigated the feasibility, minimally invasive concept, and benefits of LLIF for the treatment of DLS by observing and assessing the clinical efficacy, imaging changes, and complications following the procedure.

A retrospective analysis was performed for 52 DLS patients (12 men and 40 women, aged 65.84 ± 9.873 years) who underwent LLIF from January 2019 to January 2023. The operation time, blood loss, complications, clinical efficacy indicators (visual analogue scale [VAS], Oswestry disability index [ODI], and 36-Item Short Form Survey), and imaging indicators (coronal position: Cobb angle and center sacral vertical line-C7 plumbline [CSVL-C7PL]; and sagittal position: sagittal vertical axis [SVA], lumbar lordosis [LL], pelvic incidence angle [PI], and thoracic kyphosis angle [TK] were measured). All patients were followed up. The above clinical evaluation indexes and imaging outcomes of patients postoperatively and at last follow-up were compared to their preoperative results.

Compared to the preoperative values, the Cobb angle and LL angle were significantly improved after surgery (p < 0.001). Meanwhile, CSVL-C7PL, SVA, and TK did not change much after surgery (p > 0.05) but improved significantly at follow-up (p < 0.001). There was no significant change in PI at either the postoperative or follow-up timepoint. The operation took 283.90 ± 81.62 min and resulted in a total blood loss of 257.27 ± 213.44 mL. No significant complications occurred. Patients were followed up for to 21.7 ± 9.8 months. VAS, ODI, and SF-36 scores improved considerably at postoperative and final follow-up compared to preoperative levels (p < 0.001). After surgery, the Cobb angle and LL angle had improved significantly compared to preoperative values (p < 0.001). CSVL-C7PL, SVA, and TK were stable after surgery (p > 0.05) but considerably improved during follow-up (p < 0.001). PI showed no significant change at either the postoperative or follow-up timepoints.

Lateral lumbar intervertebral fusion treatment of DLS significantly improved sagittal and coronal balance of the lumbar spine, as well as compensatory thoracic scoliosis, with good clinical and radiological findings. Furthermore, there was less blood, less trauma, and quicker recovery from surgery.

Assessment of thoracolumbar spine flexibility is crucial for determining which osteotomy to perform (posterior column osteotomy or 3-column osteotomy) to restore sagittal balance. Although preoperative bolster supine X-rays have been used to evaluate spine flexibility, their correlation with postoperative spinopelvic parameters has not been reported. We aimed to evaluate the predictive value of bolster X-ray for correcting sagittal deformities after thoracolumbar fusion surgery.

We retrospectively evaluated patients who underwent bolster supine radiography before posterior thoracolumbar fusion. Demographic data, operative records, and radiographic parameters were also recorded. The segmental Cobb angle, defined as the angle between the upper endplate of the uppermost and lower endplates of the lowest instrumented vertebrae, was compared between bolster and postoperative X-ray to evaluate the correlation between them. The predictive value of bolster X-ray for postoperative deformity correction was measured using intraclass correlation coefficients (ICC).

Forty-two patients were included. The preoperative segmental Cobb angle (-1.4 ± 22.4) was significantly lower than the bolster segmental Cobb angle (23.2 ± 18.7, P < .001) and postoperative segmental Cobb angle (27.9 ± 22.3, P < .001); however, no significant difference was observed between the bolster and postoperative segmental Cobb angles ( P = .746). Bolster X-ray showed a very strong correlation with postoperative X-ray (r = 0.950, P < .001) for segmental Cobb angle. Bolster supine X-ray had good-to-excellent reliability for postoperative X-ray with an ICC of 0.913 (95% CI, 0.760-0.962, P < .001) for the segmental Cobb angle.

Bolster supine X-rays demonstrate good-to-excellent reliability with postoperative X-rays for segmental Cobb angles. These findings offer valuable insights into the selection of appropriate osteotomy techniques for clinical practice.

Pedicle subtraction osteotomy (PSO) is a technically complex procedure that is effective at improving the sagittal profile in spinal deformity surgery. This case report describes a 64-year-old man with a history of ten previous spinal surgeries, including failed T10-pelvis posterior spinal fusion, undergoing revision with L4 PSO. The patient regained approximately 30° of lumbar lordosis. The procedure was complicated by an uneventful intraoperative durotomy and delayed postoperative surgical site infection requiring two surgical debridements and a prolonged course of antibiotics. At the 14-month follow-up, the patient was ambulating 3 miles per day and had significantly decreased pain with no sign of recurrent infection. PSOs performed in revision cases are more challenging procedures but can achieve similar degrees of correction even in patients with multiple previous revisions.

Previous research has identified a specific subtype known as failure of pelvic compensation (FPC) in patients with adult spinal deformity (ASD). However, the criteria for assessing FPC remain inconsistent, and its impacts on spinal sagittal alignment and health-related quality-of-life (HRQoL) scores remain unclear.

To propose a novel criterion for identifying FPC based on variations in spinopelvic alignment during the transition from the supine to upright position and to evaluate the effects of FPC on patients' spinal sagittal alignment and HRQoL scores.

Retrospective cross-sectional study.

Patients with ASD from a monocenter database.

Radiographic measures, including thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt, pelvic incidence (PI), and sagittal vertical axis (SVA), were measured on lateral whole-spine radiographs. LL and SS were also measured on reconstructed lumbar computed tomography images in the sagittal view taken in the supine position. The relative functional cross-sectional area (rFCSA) of paraspinal muscles was evaluated via lumbar magnetic resonance imaging. HRQoL measures, encompassing visual analog scale for back pain (VAS-BP), Oswestry Disability Index (ODI), and Scoliosis Research Society-22R (SRS-22R), were collected.

A total of 154 patients were enrolled. Based on the calculated minimum detectable change of SS, FPC was defined as the change in SS of less than 3.4° between supine and upright positions. Patients were divided into 3 groups: sagittal balance with pelvic compensation (SI-PC), sagittal imbalance with pelvic compensation (SI-PC), and sagittal imbalance with failure of pelvic compensation (SI-FPC). Radiographic parameters and HRQoL scores were compared among the groups.

Thirty-six patients were categorized into the SB-PC group, 87 into the SI-PC group, and 31 into the SI-FPC group. Patients with low PI and small paraspinal muscles rFCSA were more prone to experiencing FPC accompanied by severe sagittal imbalance. The SI-FPC group exhibited less TK and a larger SS than the SI-PC group exhibited and had a similar SVA as that of the SI-PC group. Additionally, they displayed worse VAS-BP, ODI, SRS-function, and SRS-22 total scores than the SB-PC group displayed.

In patients with ASD, an inherently low pelvic compensatory reserve and a high fatty infiltration in paraspinal muscles are pivotal factors contributing to FPC. Compared with SI-PC patients, SI-FPC patients demonstrate a thoracic-dominant compensatory pattern for sagittal malalignment. In addition, these patients experienced more severe pain and functional decline than the SB-PC patients experienced.

[Purpose] We document the significant improvement in posturography and spinal deformity by Chiropractic BioPhysics® (CBP®) technique methods. [Participant and Methods] A 78-year-old male presented with 20 years of chronic hip and lower back pain and stiffness. The pain was 5/10 and disability was 38%. The patient also complained of walking difficulty and balance problems. Radiographic assessment demonstrated a significant thoracolumbar kyphosis and anterior C7-S1 sagittal vertical axis (SVA). Force plate posturography showed high centre of pressure (COP) parameter values including the total path length, particularly for the vestibular condition of the modified clinical test of sensory integration and balance (mCTSIB). [Results] The patient was treated with 36 sessions of CBP corrective exercises and spinal traction as well as PowerPlate balance and gait exercises. Assessment after 4-months showed improvements in sleep, pain, disability, and mobility. There was a 79 mm reduction in SVA and improved postural control in many parameters including a 49 cm and 22 cm reduction in COP total path length for the vestibular and visual trials on the mCTSIB, respectively. The pain and disability were reduced to 0/10 and 22%. [Conclusion] This case demonstrates the significant improvement in postural control as quantified by the mCTSIB with the reduction of excessive SVA as demonstrated on post-treatment x-rays.

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

To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility.

A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility.

Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline.

Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

This study evaluates the influence of spinal malalignment on health-related quality of life (HRQOL) in a long-level fusion spine.

This was a retrospective analysis of 121 consecutive patients with DLS after long-segment fusion. HRQOL and radiographic parameters were collected at final follow-up. For postoperative residual Cobb angle (CA), patients were divided as follows: group (0) (CA < 10°), group (+) (CA 10°∼20 °), and group (++) (CA > 20°). For postoperative coronal vertical axis (CVA), patients were separated as follows: group (0) (CVA < 2 cm), group (+) (CVA 2 ∼ 3 cm), and group (++) (CVA > 3 cm). Patients were also grouped by the sagittal modifiers as group (0), group (+), and group (++) according to the Scoliosis Research Society (SRS)-Schwab classification, respectively.

Visual analog scale (VAS) for back was significantly lower in CA 10°∼20° group compared to other groups. Patients with remnant CA > 20° showed worse Oswestry Disability Index (ODI), SRS-22 and the 36-item Short Form Health Survey (SF-36) - physical component scores (PCS). Sagittal vertical axis (SVA) showed significant correlation with HRQOLs after surgery, and the statistical significance of ODI, SRS-22 and SF-36 scores was observed among subgroups.

In long-level fused spine, residual CA > 20° resulted in worse clinical outcomes and was recommended to avoid during surgery. And 10° to 20° residual CA was acceptable in DLS patients and even better than Cobb angle < 10° in several HRQOLs, therefore strictly pursing upright alignment seems unnecessary. SVA also showed effectiveness in assessing HRQOL in the fixed spine.

Pelvic tilt (PT) is an important parameter for orthopedic surgeries involving hip and spine, typically determined from sagittal pelvic radiographs. However, various challenges can compromise the feasibility of measurement from sagittal imaging, including obscured landmarks, anatomical variations, hardware interference, and limited medical resources. Addressing these challenges and with the aim of reducing radiation exposure to patients, our study developed a novel method to estimate PT from antero-posterior (AP) radiographs, using vertical distances from the pelvic outlet and obturator foramen. We correlated these measurements with PT, defined both anatomically (anterior pelvic plane, PTa) and mechanically (centers of femoral heads and sacral plate, PTm). The study explored creating linear, exponential, and multivariate regression models based on twelve 3D CT-derived pelvic models (six men, six women), simulating AP radiograph projections with controlled PTs. We then validated these models against 105 pairs of patient stereoradiographs. Statistical analysis revealed that combined exponential-linear models yielded the most accurate results, with Pearson correlation coefficients of 0.75 for PTa and 0.77 for PTm, and mean absolute errors of 3.7° ± 2.6° for PTa and 4.5° ± 3.4° for PTm, showing excellent measurement reliability (all ICCs > 0.9) without significant gender discrepancies. In conclusion, this study presents a validated, simple, and accessible method for estimating PT using AP radiograph parameters, supported by the Supporting Information S1: Excel Tool, showing great potential for clinical application in hip and spine procedures.

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

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

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

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

The relationship of spinopelvic parameters with spondylolisthesis is widely explored. However, there is scarce evidence on correlation of tuberculosis of lumbar spine with respect to spinopelvic harmony. The current study aims to find the association between functional outcomes and spinopelvic parameters in lumbar spine tuberculosis treatment.

A total of 47 patients with active tuberculosis confined to lumbar spine were prospectively analyzed and divided into 2 groups according to mode of intervention. Group A included 26 operatively managed patients and group B had 21 conservatively managed cases. Functional parameters comprising Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) along with spinopelvic radiologic parameters (pelvic incidence [PI], pelvic tilt [PT], sacral slope [SS], lumbar lordosis [LL], PI-LL, sagittal vertical axis) in both groups were analyzed at 0 and 6 months of follow-up.

Both the groups showed significant improvement from initial presentation to final follow-up in ODI (Group A: 85.4 ± 12.1-12.3 ± 3.2, P = 0.02; Group B: 82.5 ± 10.06-36.8 ± 11.9, P = 0.04) and VAS (Group A: 8.1 ± 1.2-1.4 ± 0.9, P = 0.02; Group B: 8.5 ± 0.09-3.5 ± 1.1, P = 0.02). Statistically significant (P < 0.05) difference was observed in both functional outcome parameters between the 2 groups at 2-month and 6-month follow-up, compared with nonsignificant difference (P > 0.05) at presentation. Better improvements of spinopelvic parameters of PT, SS, LL, PI-LL were observed in Group A and in both groups the difference of these parameters correlated with differences of functional outcome parameters, though PI showed no correlation.

The spinopelvic parameters played significant role in functional outcome. There is better functional outcome when LL is adequately restored. Surgical correction offered betterment of spinopelvic parameters like PT, SS, an sagittal vertical axis, which in turn leads to improvement in functional outcome.

There are few data on the impact of periacetabular osteotomy (PAO) on sagittal spinopelvic alignment. Prior studies have attempted to delineate the relationship by performing measurements on AP radiographs and using mathematical models to determine changes in postoperative pelvic tilt. This information is clinically significant to a surgeon when evaluating acetabular/pelvic position intraoperatively and understanding spinopelvic alignment changes postoperatively; therefore, radiographic changes from PAO should be described in more detail.

In this study, we asked: (1) Does the performance of PAO result in consistent changes in spinopelvic alignment, as measured on EOS radiographs? (2) Does this differ for unilateral versus bilateral PAOs? (3) Does this differ in the setting of a mobile spine versus an immobile spine? (4) Does this differ based on preoperative pelvic tilt?

Mean preoperative and at least 1-year postoperative (15 ± 8 months from surgery, minimum 11 months, maximum 65 months) EOS hip-to-ankle standing and sitting radiographs for 55 patients in a prospectively collected registry who underwent PAO with a single surgeon from January 1, 2019, to January 11, 2022, were measured for pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, lateral center-edge angle, L1 pelvic angle, and pubic symphysis to the sacroiliac index. Normality was assessed and paired sample t-tests (normally distributed data) or Wilcoxon signed rank tests (not normally distributed data) were utilized to assess if any measurements changed from preoperative to postoperative. Patients were then divided based on whether they had unilateral or bilateral dysplasia and unilateral or bilateral surgery, and these subgroups were analyzed the same way as the entire cohort. Two more subgroups were then formed based on lumbar mobility, defined as a change in sitting-to-standing lumbar lordosis less or greater than 1 SD from the population mean preoperatively, and the subgroups were analyzed the same way as the entire cohort. Finally, two additional subgroups were formed, preoperative standing pelvic tilt less than 10° and more than 20°, and analyzed the same as the entire cohort.

For the entire cohort, the median (IQR) standing lateral-center edge angle increased 17°, from a median of 21° (10°) to a median of 38° (8° [95% confidence interval (CI) 16° to 20°; p < 0.001). The median sitting lateral center-edge angle increased 17°, from a median of 18° (8°) to a median of 35° (8° [95% CI 14° to 19°]; p < 0.001). Standing pelvic incidence increased from 50° ± 11° to 52° ± 12° (mean difference 2° [95% CI 1° to 3°]; p = 0.004), but there were no changes for other measured parameters. There were no changes in any of the spinopelvic parameters for patients with unilateral dysplasia receiving a unilateral PAO, but patients with bilateral dysplasia who underwent bilateral PAOs demonstrated an increase in pelvic incidence from 57° (14°) to 60° (16°) (95% CI 1° to 5°; p = 0.02) and a decrease in pubic symphysis to sacroiliac index from 84 mm (24 mm) to 77 mm (23 mm) (95% CI -7° to -2°; p = 0.007). Patients with mobile lumbar spines preoperatively did not exhibit any changes in sagittal spinopelvic alignment, but patients with immobile lumbar spines preoperatively experienced several changes after surgery. Patients with less than 10° of standing pelvic tilt demonstrated a median (IQR) 2° increase in pelvic incidence from median 43° (9°) to 45° (12° [95% CI 0.3° to 4°]; p = 0.03), but they did not experience any other changes in sagittal spinopelvic alignment parameters postoperatively. Patients with preoperative pelvic tilt more than 20° did not experience any change in sagittal spinopelvic parameters.

PAO increases pelvic incidence, potentially because of anterior translation of the hip center. There were no changes in other spinopelvic parameters postoperatively except after bilateral PAO. Additionally, patients lacking spine mobility preoperatively, indicated by a minimal change in lumbar lordosis between standing and sitting positions, may experience several changes in spinopelvic alignment, including increased mobility of their spine after PAO. This may be because of decreased compensatory spine splinting after increasing acetabular coverage, but further research including patient-reported outcomes is warranted.

Level III, therapeutic study.