Tag: Roussouly classification

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How to Reduce the Risk of Mechanical Failures in Adult Deformity Surgery: Comparing GAP Score and Roussouly Type Restoration

Global Spine Journal 2025, Vol. 0(0) 1–15

DOI: 10.1177/21925682251328285

This study investigates the predictors of mechanical failure in adult spinal deformity surgery, highlighting the significance of the GAP score and Roussouly type restoration in minimizing complications. A proper post-operative GAP Score and spinal alignment restoration are crucial for reducing mechanical failure rates.

Study Design and Methods

• Retrospective cohort study with a 5-year follow-up on adult spinal deformity cases.

• Inclusion criteria: Patients over 18, with at least 4 vertebrae fused.

• Data collected: Demographic, surgical, spinopelvic parameters, and complications.

Key Findings

• Mechanical Complications: Revision surgery rate was 40.6%.

• Higher post-operative GAP scores linked to increased junctional failure risk.

• Roussouly Type Restoration: Failure to restore original type increases mechanical failure risk.

Predictive Analysis

• GAP Score and Roussouly Type are top predictors for mechanical failure.

• Gradient Boosting model showed high predictive accuracy (ASE 0.073).

• Kaplan-Meier Analysis: Higher GAP scores linked to earlier junctional failures.

Recommendations

• Surgical Planning: Restore original Roussouly type and achieve proper lumbar lordosis.

• Avoid Pelvic Retroversion: Ensure proper global balance.

Statistical Analysis

• Logistic regression confirmed GAP score and Roussouly type as significant predictors.

• ROC Curves: Moderate association between GAP score and revision surgery need.

Limitations

• Retrospective design with potential selection bias.

• Asymmetrical sample size of GAP score groups.

Level of Evidence

3 retrospective cohort study

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Can pelvic incidence affect changes in sagittal spino‑pelvic parameters between standing and sitting positions in individuals with lumbar degenerative disease?

European Spine Journal (2024) 33:4598–4604

The aim of this study was to explore the correlation between PI and standing-to-sitting changes of the sagittal alignment in patients with lumbar degenerative diseases, and investigate the differences in posture changes among Roussouly types.

Methods A total of 209 patients with lumbar degenerative disease were retrospectively included in this study. All the patients received lateral full body imaging in both standing and sitting positions. Sagittal parameters including SVA, OD-HA, PT, PI, PT/PI, SS, LL, TK, Upper LL (L1-L4) and Lower LL (L4-S1) were measured in both standing and sitting position, and the parameters were compared between two positions. The correlations between PI and lumbo-pelvic changes were analyzed. The postural changes were compared among different Roussouly types.

Results From standing to sitting, all the parameters except PI significantly changed, including SVA, OD-HA, PT, PT/PI, SS, LL, TK, Upper LL and Lower LL. The contribution of lower LL was greater to global LL than upper LL. PI had a significant correlation with ΔPT, ΔSS, ΔLL, ΔUpper LL and ΔLower LL. From standing to sitting, type 4 patients had the most pronounced ΔPT, ΔSS and ΔLL, and ΔLower LL of types 3 and 4 were greater than that of types 1 and 2.

Conclusions In patients with degenerative disease, PI plays an important role in determining the extent of lumbo-pelvic changes from standing to sitting. Among different Roussouly types, type 4 patients have the most pronounced changes of PT, SS and LL, suggesting the relatively greater flexibility of pelvis and lumbar spine.

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Correlation between the spinopelvic type and morphological characteristics of lumbar facet joints in degenerative lumbar spondylolisthesis

J Neurosurg Spine 38:425–435, 2023

The correlation between the spinopelvic type and morphological characteristics of lumbar facet joints in patients with degenerative lumbar spondylolisthesis (DLS) was investigated.

METHODS One hundred forty-two patients with L4 DLS were enrolled (DLS group), and 100 patients with lumbar disc herniation without DLS were selected as the control group (i.e., non–lumbar spondylolisthesis [NL] group). Morphological parameters of L4–5 facet joints and L4–5 disc height and angle were measured on 3D reconstructed CT images; namely, the facet joint angle (FJA), pedicle–facet joint angle (PFA), facet joint tropism, and facet joint osteoarthritis (OA). The L4 slip percentage, sacral slope, and lumbar lordosis were measured on radiographs. Patients in the DLS and NL groups were divided into 4 subgroups according to Roussouly classification (types I, II, III, and IV).

RESULTS In the DLS and NL groups, as the spinopelvic type changed from type II to type IV, the facet joint morphology showed a gradual sagittal orientation in the FJA, a gradual horizontal orientation in the PFA, a gradual severity in OA, and a gradual increase in the slip percentage, but changes were completely opposite from type I to type II. Additionally, compared with the NL group, the facet joint morphology in the DLS group had more horizontal orientation in PFA, more sagittal orientation in the FJA, and the facet joint tropism and OA were more severe.

CONCLUSIONS Facet joint morphology was correlated with spinopelvic type in the slip segment of DLS. Facet joint morphology was part of the joint configuration in different spinopelvic types, not just the result of joint remodeling after DLS. Moreover, morphological changes of the facet joints and DLS interacted with each other. Additionally, morphological remodeling of the facet joints in DLS played an important role in spinal balance and should be taken into consideration when designing a surgical approach.

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