Diário da Espinha

Correlation of Spinopelvic Parameters in Lumbar Spine Instability

Abstract

Madhan Jeyaraman, Vijay Kumar K, Naveen Jeyaraman, Amarendra Singh, Lokesh Sharma and Kartheek Aradhyula

Introduction: Sagittal spino-pelvic instability is the most common cause for chronic low back pain. Legaye stated that the pelvic incidence (PI) is an anatomical parameter for assessing spinal stability. Pelvic incidence can be calculated by adding pelvic tilt and sacral slope. Sacral table angle (STA) is the angle between the superior sacral endplate and the trailing edge line of sacrum.

Objective: To prove the temporal association of pelvic incidence and sacral table angle and lumbar instability in patients with chronic low back pain.

Materials and methods: A total of 191 cases with nonspecific low back pain with or without lumbar instability were analysed with spinal radiographs. The pelvic incidence and sacral table angle were calculated for L3 – L4, L4 – L5 and L5 – S1 levels.

Results: Out of 191 cases, the levels of L5 – S1 cases showed 5% translation and 10° angulation. We observed a significantly statistical difference between two groups in terms of pelvic incidence (p=0.01) and sacral table angle (p<0.01). The lumbar instability of L5 – S1 segment is associated with lower pelvic incidence and increased sacral table angle. The Spearman’s Rank correlation coefficient (rho ρ) for the study was 0.745 which imply highly positive correlation between pelvic incidence and sacral table angle and lumbar instability.

Conclusion: The spino-pelvic parameters influence the evolution of spinal degenerative disease. We observed that the patients with chronic low back pain without lumbar instability showed normal or decreased PI and increased STA whereas patients with chronic low back pain with lumbar instability showed increased PI and decreased STA. The cases with increased PI and decreased STA are prone to develop degenerative spinal pathology or discogenic pathology which alters the postural balance of spinal column.