Association Between Radiological Severity of Lumbar Spinal Stenosis and Spinopelvic Parameters in Adult Patients With Achondroplasia

Abstract

BACKGROUND AND OBJECTIVES: Adults with achondroplasia are more vulnerable to suffer from neurogenic claudication because of a congenital narrow spinal canal, which makes them susceptible to lumbar spinal stenosis (LSS). The study aims to investigate the correlations between sagittal alignment parameters and the degree of LSS in patients with achondroplasia with LSS. METHODS: The radiological data of adult achondroplasts presented to the neurosurgical clinic of our medical center from 2019 to 2022 were collected. Lumbar stenosis was graded using the Schizas scale, and the dural sac cross-sectional area (DSCA) was measured. The angles defining the spinopelvic parameters comprising lumbar lordosis, thoracolumbar kyphosis, sagittal vertical axis, pelvic tilt, sacral slope, and pelvic incidence were measured. Spearman or Pearson correlation was used to investigate the association between sagittal misalignment and LSS. RESULTS: A total of 34 achondroplastics were enrolled, with a median age of 44.3 ± 15.5 years, ranging from 18.6 to 78.5 years. Larger thoracolumbar kyphosis was associated with more severe stenosis according to the Schizas scale of the L12 lumbar level (r = 0.44, P = .020, 95% CI [0.08, 0.70]). Larger sagittal vertical axis correlated with a smaller DSCA at L23 (r = −0.53, P = .036, 95% CI [−0.81, −0.04]) and L45 (r = −0.66, P = .004, 95% CI [−0.87, −0.26]). Larger pelvic tilt was demonstrated to be associated with a smaller DSCA of the L34 lumbar level (r = −0.42, P = .027, 95% CI [−0.68, −0.05]) and the L45 lumbar level (r = −0.47, P = .011, 95% CI [−0.71, −0.12]). CONCLUSION: The upper LSS may be attributed to an increased kyphosis of the thoracolumbar spine. On the contrary, the lower LSS seemed to be correlated with a more backward tilt of the pelvis.