Four types of global spine sagittal alignment and compensation mechanism in adult patients with lumbar degenerative disease

The effect of degenerative scolioisis on segmental thoracolumbar sagittal alignment compared to age- and pelvic incidence-matched reference values

INTRODUCTION

In asymptomatic subjects, variations of sagittal alignment parameters according to age and pelvic incidence (PI) has been reported. The aim of this observational study was to describe thoraco-lumbar sagittal alignment in patients with degenerative scoliosis and to compare them to asymptomatic individuals, seeking for the specific effect of deformity in similar age and PI groups.

MATERIALS AND METHODS

Full spine radiographs of 235 asymptomatic subjects and 243 scoliosis patients were analyzed: cervico-thoracic inflexion point (CTIP), thoraco-lumbar inflexion point (TLIP), lumbar lordosis (LL) L1-S1, LL (TLIP-S1), LL superior arch (TLIP-lumbar apex), LL inferior arch (lumbar apex-S1), PI, thoracic kyphosis (TK) T5-T12, TK T1-T12, number of vertebrae CTIP-TLIPandTLIP-S1. The distribution of parameters was analyzed using a Bayesian inference (significant when Pr > 0.975 or Pr < 0.025). Comparisons between reference (R) and pathologic (P) groups were matched according to age (40-60 years; >60 years) and PI (< 45°; 45-60°; >60°).

RESULTS

LL L1-S1 was significantly lower in the P-group (Pr = 1.0), decreased with age (Pr > 0.99) and increased with PI (Pr < 0.001). In contrast, there was no significant decrease with age for LL (TLIP-S1) or LL (superior arch) (respectively Pr < 0.92 and Pr > 0.19). LL in the inferior arch was significantly lower in the P-group (Pr = 1.0) and decreased with age (Pr = 0.99). The number of vertebrae TLIP-S1 was significantly lower in the P-group compared to the reference group (Pr < 0.001).Thoracic kyphosis T1-T12 was significantly lower in the P-group (Pr < 0.001), without significant influence of age or PI. The number of vertebrae CTIP-TLIP increased significantly in the P-group (Pr < 0.001) and with PI (Pr < 0.004).

CONCLUSION

This observational study highlights specific thoraco-lumbar sagittal alignment adaptations in degenerative scoliosis, matched on age and PI. Beyond the decrease in LL due to aging, degenerative scoliosis leads to a distal migration of the TLIP, an increase in the number of vertebrae in TK and a decrease in LL. This phenomenon was linked to kyphosis at the thoraco-lumbar junction due to scoliosis and was more important in high PI.

Early outcomes of oblique lateral interbody fusion with posterior fixation versus posterior interbody fusion with fixation for treating adult degenerative scoliosis

OBJECTIVE

To compare the surgical trauma and outcomes between oblique lateral interbody fusion (OLIF) and posterior fixation and posterior lumbar interbody fusion (PLIF) with fixation for adult degenerative scoliosis (ADS).

METHODS

We included ADS patients who underwent OLIF with fixation or PLIF with fixation treatment from June 2020 to December 2022. The preoperative and postoperative spinal pelvic parameters were measured using X-rays. Clinical symptoms were measured using the Oswestry Disability Index and a visual analog scale. We recorded operation time, intraoperative blood loss, blood transfusion, albumin infusion, surgical fixation segment, surgical osteotomy segment, time, and drainage volume.

RESULTS

Forty patients with ADS were included: 20 with OLIF with posterior fixation and 20 with PLIF matched for age, sex, pelvic incidence, and Cobb angle with the OLIF group. There were no significant differences in age, gender, BMI, preoperative spinal parameters, or preoperative clinical symptoms between the groups (p > 0.05). There were no statistical differences in postoperative spinal parameters or clinical symptoms (p > 0.05). Patients in the OLIF group had less intraoperative blood loss (p < 0.01) and fewer intraoperative blood transfusions (p < 0.001) than the posterior surgery group. The number of fixed segments was fewer (p < 0.01), and there were fewer total osteotomy segments (p < 0.001).

CONCLUSION

OLIF with posterior fixation surgery can achieve the same corrective effect and efficacy as a posterior internal fusion with fixation surgery for treating ADS. OLIF with posterior fixation surgery causes less trauma and reduces the number of fixation segments.

Compensatory classification in spine sagittal malalignment with lumbar degeneration

Objective

To generate a compensatory classification to evaluate sagittal spinal malalignment with lumbar degeneration.

Methods

We included 162 patients with low back pain who underwent full-length spinal radiography in our hospital from August 2019 to October 2021. Using full-length spine X-rays, we measured pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), C7 slope (C7S), thoracolumbar kyphosis (TLK), and C7 sagittal vertical axis (SVA). We also recorded the Oswestry Disability Index (ODI) and visual analog scale (VAS). Patients were divided into four groups based on the SRS-Schwab classification and four other groups based on the compensatory classification.

Results

ODI correlated with age, SS, LL, TK, C7-SVA, SRS-Schwab classification, and compensatory classification. Lumbar VAS score correlated with LL, TK, C7-SVA, SRS-Schwab classification, and compensatory classification. Leg VAS score only correlated with LL. Hidden imbalance and imbalance with compensation had more significant PT and larger TK than balance patients. The symptoms of the four compensatory classification groups gradually worsened.

Conclusion

The spinal-pelvic sagittal balance in patients with lumbar degeneration based on pelvic and thoracic compensation can reflect spinal balance and symptoms. This parameter might help evaluate spine sagittal alignment in elderly patients with lumbar degeneration.

Mechanisms of compensatory for cervical lordosis changes after laminectomy with fusion

Background

The compensatory mechanisms for cervical lordosis change after laminectomy with fusion was not clear. The objective of this study was to evaluate the compensatory behaviors for cervical lordosis change after laminectomy with fusion.

Methods

This was a retrospective radiological analysis of 43 patients with cervical spondylotic myelopathy who underwent laminectomy with fusion (LCF). The following cervical parameters were measured: C2-7 Cobb angle (C2-7), occiput-C2 angle (O-C2), the cervical sagittal vertical axis (cSVA), and T1 slope (T1S). The difference was calculated for all angle parameters between the two time points using the following formula: the amount of change (Δ) = (value at the follow-up)—(preoperative value). Non-parametric tests and the t-test were used to compare the difference. The Pearson correlation test was performed, and stepwise multiple regression analysis was performed to determine the best correlation between ∆cSVA and ∆T1S.

Results

The mean age of 43 patients was 65.51 ± 9.80 years. All patients were classified into two subgroups based on ΔcSVA: Group M (maintained) and, Group I (increased). The preoperative O-C2, C2-7, T1S, and cSVA were similar between Group M and group I (p = 0.950, p = 0.731, p = 0.372, and p = 0.152, respectively). Postoperative O-C2 and postoperative cSVA were significantly different (p = 0.036 and p = 0.004, respectively). ∆O-C2, ∆T1S and ∆cSVA were significantly different between the two groups (p = 0.006, p = 0.000, and p = 0.000, respectively). ΔcSVA had significant correlations with ΔO-C2 neutral angle (r = 0.377) and ΔT1S (r = 0.582). A linear regression equation was established: ΔcSVA = 0.602 + 0.103 * ΔT1S (R = 0.582, R² = 0.339).

Conclusions

The decrease of TIS should be the first and foremost compensation for the loss of lordosis in C2-7 segments after LCF. When the change of T1S alone can not prevent the deterioration of cervical sagittal balance, further increases in the O-C2 segment occur.