Analysis of Spinal-Pelvic Sagittal Plane Parameters in Patients With Highly Upward-Migrated Lumbar Disc Herniation

Retrospective cohort study.

To investigate spinopelvic sagittal alignment characteristics in patients with highly upward-migrated lumbar disc herniation (HUM-LDH).

Abnormal spinopelvic sagittal morphology is associated with lumbar degenerative disorders. However, sagittal alignment features specific to HUM-LDH remain unclear.

We retrospectively analyzed 110 hospitalized HUM-LDH patients treated between January 2020 and June 2024. Two control groups were included: 138 asymptomatic adults without low back/leg pain undergoing health examinations (control group 1) and 110 patients with nonmigrated lumbar disc herniation (control group 2). On standing full-spine radiographs, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), PI-LL mismatch (PI-LL), and sagittal vertical axis (SVA) were measured and compared among groups.

Compared with control group 1, the HUM-LDH group had significantly lower LL and significantly higher PI, PT, TLK, TK, SVA, and PI-LL (all P<0.05), with no difference in SS. Compared with the age-matched control group 2, HUM-LDH showed significantly higher PI and TK (P<0.05), whereas PT, SS, LL, TLK, SVA, and PI-LL were not significantly different. In the HUM-LDH group, LL correlated strongly with SS and moderately with PI; PI correlated moderately with SS and PT; SVA correlated weakly with LL. The Roussouly classification showed type II predominance in HUM-LDH (60.0%); its distribution was similar to control group 2 but differed from control group 1 (P<0.05).

HUM-LDH is associated with distinct spinopelvic sagittal alignment. Higher PI and greater TK are associated with this subtype and may help identify HUM-LDH.