The correlation between sagittal spinopelvic alignment and degree of lumbar degenerative spondylolisthesis

Background: Recently, several authors reported that a high pelvic incidence (PI) might be a predisposing factor to the development of anterior slip in the vertebral body in degenerative spondylolisthesis (DS). The purpose of this study was to analyze patients with DS using a multiple linear regression model, in terms of the correlation between the sagittal spinopelvic parameters and the severity of slip in each lumbar spine, including both anterior and posterior directions.

Methods: Standing lateral radiographs were taken of 104 patients (59 women and 45 men) with lower back pain. The spinopelvic parameters, including PI, sacral slope (SS) and pelvic tilt (PT), angle of thoracic kyphosis (TK), angle of lumbar lordosis (LL), and sagittal vertical axis offset (SVA) were measured. Additionally, the %Slip was measured at each level between the L1 and L5. The slip direction was presented as plus to the anterior, and minus to the posterior.

Results: The PI, SS, and/or LL correlate with L3, L4, and/or L5%Slips. The TK and SVA did not correlate with %Slip. A multiple linear regression model shows that PI and LL were significant predictors for L4 %Slip. The ROC curve demonstrated a PI cutoff value of 51.3° and an LL cutoff value of 45.0° to be predictors of anterior slip at L4. Also, our regression models revealed that PI for L3 %Slip and SS for L5 %Slip constitute significant risk factors, while determination coefficients were low.

Conclusions: Our results suggest that high PI and LL are significant predictors for L4 anterior slip. At L4, the anterior slip risk-factor cutoff value was 51.3° for PI and 45.0°for LL. Additionally, our results suggest that high PI and SS could comprise risk factors for L3 anterior slip and L5 anterior slip, respectively.