Two different types of postoperative sagittal imbalance after long instrumented fusion to the sacrum for degenerative sagittal imbalance

Correlation analysis of spine-pelvis parameters and age with lumbar paravertebral muscle degeneration in middle age and older adults

OBJECTIVE

To analyze the correlation between spine-pelvis parameters, age and lumbar paravertebral muscle degeneration in middle-aged and older adults.

METHOD

This retrospective study involved 143 middle-aged and elderly patients with suspected lumbar paravertebral muscle degeneration treated at The Third Hospital of Hebei Medical University between January 2021 and June 2023. Based on confirmed diagnoses, patients were divided into a degenerative group (57 cases) and a non-degenerative group (86 cases). Clinical data were analyzed to explore the relationship between pelvic parameters, age, and lumbar paravertebral muscle degeneration. Univariate and multivariate logistic regression were used to identify risk factors, and Receiver Operating Characteristic (ROC) analysis was performed to evaluate the predictive value of these factors. Differences in areas under the curve (AUC) for clinical factors were assessed using the DeLong test.

RESULT

No significant differences were found between the two groups in clinical data, except for age (P<0.05). Comparison of spine-pelvis parameters revealed that the pelvic tilt (PT) and pelvic incidence (PI) were significantly higher in the degenerative group than those in the non-degenerative group, while the sacral slope (SS) and lumbar lordosis (LL) were lower (all P<0.05). Additionally, the CSA ratios between the third and fourth lumbar vertebrae (L3/4) and between the fourth and fifth lumbar vertebrae (L4/5) were found to be significantly lower in the degenerative group as opposed to those in the non-degenerative group (all P<0.05). Kendall's analysis showed that age and spine-pelvis parameters (PT, PI) were positively correlated with lumbar paravertebral muscle degeneration (OR=0.733, 0.639, 0.695; P<0.0001). In contrast, spine-pelvic parameters (SS, LL) were negatively correlated with degeneration (OR=-0.695, -0.698; P<0.0001). Pearson's correlation analysis also revealed a positive correlation between age and spine-pelvic parameters (PT, PI) (r=0.826, 0.985, P<0.001), and a negative correlation between age and spine-pelvic parameters (SS, LL) (r=-0.861, -0.942, P<0.001). Additionally, spine-pelvic parameter PT was negatively correlated with CAS ratio of L3/4 disc levels (r=-0.412, P<0.000). Logistic multivariate regression analysis identified age (OR=0.616, P<0.0001), PT (OR=0.827, P<0.0001), SS (OR=1.095, P=0.004), LL (OR=1.148, P=0.019), PI (OR=0.853, P<0.0001), CAS ratio of L3/4 (OR=1.977, P=0.002) and CAS ratio of L4/5 (OR=1.739, P=0.009) levels as independent risk factors for lumbar paravertebral muscle degeneration (all P<0.05). ROC results showed that the AUCs for age, PT, SS, LL, PI, L3/4, and L4/5 in predicting lumbar paravertebral muscle degeneration in middle-aged and elderly people were 0.949, 0.828, 0.642, 0.779, 0.850, 0.683, 0.677, respectively (all P<0.05).

CONCLUSION

Lumbar paravertebral muscle degeneration in middle-aged and elderly individuals is significantly associated with both age and spine-pelvic parameters. These findings suggest that degeneration is not only age-related but also influenced by spine-pelvic configuration, providing a clinical basis for preventing lumbar paravertebral muscle degeneration.

Anterior Column Realignment Through Open Pre-posterior Release-Anterior-Posterior Fusion Versus Hybrid Minimally Invasive-Anterior-Posterior Fusion for Dynamic Sagittal Imbalance of the Spine

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

To investigate the clinical and radiological outcomes after anterior column realignment (ACR) through pre-posterior release-anterior-posterior surgery (PAP) and minimally invasive surgery -lateral lumbar interbody fusion (MIS-LLIF) using hybrid anterior-posterior surgery (AP).

METHODS

A total of 91 patients who underwent ACR with long fusions from T10 vertebra to the sacropelvis with a follow-up period of at least 2 years after corrective surgery for adult spinal deformity were included and divided into two groups by surgical method: AP and PAP. AP was performed in 26 and PAP in 65 patients. Clinical outcomes and radiological parameters were investigated and compared. A further comparison was conducted after propensity score matching between the groups.

RESULTS

The more increase of LL and decrease of PI-LL mismatch were observed in the PAP group than in the AP group postoperatively. After propensity score matching, total operation time and intraoperative bleeding were greater, and intensive care unit care and rod fracture were more frequent in the PAP group than in the AP group with statistical significance. Reoperation rate was higher in PAP (29.2%) than in AP (16.7%) without statistical significance.

CONCLUSIONS

PAP provides a more powerful correction for severe sagittal malalignment than AP procedures. AP results in less intraoperative bleeding, operation time, and postoperative complications. Therefore, this study does not suggest that one treatment is superior to the other.

LEVEL OF EVIDENCE

III.

Sagittal Realignment Following Decompression for Lumbar Spinal Stenosis in Elderly Patients: A Comprehensive EOS Imaging Analysis

BACKGROUND/OBJECTIVES

This study investigated whether decompression surgery for lumbar spinal stenosis can effectively improve sagittal alignment in elderly patients. With the growing focus on sagittal balance in spinal surgery, this study aimed to evaluate post-decompression alignment changes and identify the factors influencing these changes using the EOS imaging system.

METHODS

A retrospective analysis was conducted on 49 elderly patients who underwent decompression surgery alone for lumbar spinal stenosis. Radiologic parameters, measured using the EOS system, and clinical outcomes were assessed preoperatively, at two weeks postoperatively, and at one year postoperatively. Patients were grouped based on the improvement of the sagittal vertical axis (SVA) by 25 mm or more. A multivariate analysis was performed to identify factors affecting sagittal alignment changes.

RESULTS

Significant sagittal alignment improvements were observed postoperatively, including a notable increase in thoracic kyphosis and a decrease in SVA observed at one year. Clinical outcomes, such as the Oswestry disability index (ODI) and EQ-5D, significantly improved at both two weeks and one year postoperatively compared to preoperative values (all p-values < 0.05). Multivariate analysis revealed that greater preoperative SVA and higher ODI were significant predictors of sagittal alignment changes (odds ratio [OR] for SVA = 1.014, OR for ODI = 1.034).

CONCLUSIONS

Decompression surgery for lumbar spinal stenosis in elderly patients can result in significant improvements in sagittal alignment and clinical outcomes. The study suggests that decompression alone is a viable surgical option for elderly patients, particularly those with a greater preoperative sagittal imbalance and disability, even in the absence of major deformities.

An evidence based conceptual framework for the multifactorial understanding of proximal junctional kyphosis

Introduction

Adult spinal deformity (ASD) is a debilitating pathology that arises from a variety of etiologies. Spinal fusion surgery is the mainstay of treatment for those who do not achieve symptom relief with conservative interventions. Fusion surgery can be complicated by a secondary deformity termed proximal junctional kyphosis (PJK).

Research question

This scoping review evaluates the modern body of literature analyzing risk factors for PJK development and organizes these factors according to a multifactorial framework based on mechanical, tissue or demographic components.

Materials and methods

An extensive search of the literature was performed in PubMed and Embase back to the year 2010. Articles were assessed for quality. All risk factors that were evaluated and those that significantly predicted the development of PJK were compiled. The frequency that a risk factor was predictive compared to the number of times it was evaluated was calculated.

Results

150 articles were reviewed. 57.3% of papers were of low quality. 76% of risk factors analyzed were focusing on the mechanical contribution to development of PJK versus only 5% were focusing on the tissue-based contribution. Risk factors that were most frequently predictive compared to how often they were analyzed were Hounsfield Units of vertebrae, UIV disc degeneration, paraspinal muscle cross sectional area and fatty infiltration, ligament augmentation, instrument characteristics, postoperative hip and lower extremity radiographic metrics, and postoperative teriparatide supplementation.

Discussion and conclusion

This review finds a multifactorial framework accounting for mechanical, patient and tissue-based risk factors will improve the understanding of PJK development.