380 - Lumbar Stenosis Severity Predicts Worsening Sagittal Malalignment on F...

Oral Posters: Cervical

Presented by: A.J. Buckland - View Audio/Video Presentation (Members Only)

Author(s):

A.J. Buckland(1), S. Ramchandran(1), L.M. Day(2), S. Bess(3), T.S. Protopsaltis(1), P.G. Passias(1), B. Diebo(4), B. Liabaud(5), R. Lafage(4), V. Lafage(4), T.J. Errico(1)

(1) Hospital for Joint Diseases at NYU Langone Medical Center, Department of Orthopaedic Surgery, New York, NY, United States
(2) SUNY Downstate College of Medicine, New York, NY, United States
(3) Denver International Spine Center, Denver, CO, United States
(4) Hospital for Special Surgery, New York, NY, United States
(5) SUNY Downstate Medical Center, Brooklyn, NY, United States

Abstract

Summary: Patients with degenerative lumbar stenosis lean forward to relieve symptoms of neurogenic claudication or radiculopathy. Standing alignment was assessed with full-body stereoradiographs, and severity of stenosis with supine MRI. Spinopelvic alignment progressively worsens with increasing MRI graded severity of lumbar stenosis. The changes in PI-LL mismatch between standing and sitting imply this mismatch is a compensatory mechanism. Increasing levels of stenosis did not predict worse alignment, nor did severity of foraminal stenosis. Severity of stenosis did not predict worse HRQoL.

Hypothesis: Patients with increasing severity of degenerative lumbar stenosis will have worsening sagittal spinal malalignment. Design: Retrospective clinical and radiological review.

Introduction: Patients with degenerative lumbar stenosis adopt a forward flexed posture to relieve symptoms of neurogenic claudication and radiculopathy. The relationship between sagittal alignment and the severity of lumbar stenosis on MRI has not previously been studied.

Methods: Degenerative lumbar stenosis (DLS) patients were identified from a retrospective clinical database with corresponding full-body stereoradiographs. Exclusion criteria included coronal malalignment, prior spine surgery, spondylolisthesis >grade 1, non-degenerative spinal pathology or skeletal immaturity. Central stenosis severity, graded (0-3) (Lee, 2011) and supine lordosis were measured on MRI. Standing pelvic, regional, lower limb and global sagittal alignment was measured with validated software. Patient reported outcome measures (PROMs) were also analyzed including ODI, VAS Back and Leg, and EQ5D. Sagittal alignment and PROMs were compared between stenosis groups with one-way ANOVA and statistical significance set at p< 0.05.

Results: 125 patients were identified with DLS and appropriate imaging. No patients had grade 0, 28 had grade 1, 44 grade 2 and 53 grade 3 stenosis. As the grade of stenosis increased, patients displayed stepwise significantly increasing standing PI-LL mismatch, PT, Sagittal Vertical Axis and TPA (p< 0.05, table 1). No significant difference was found in Pelvic Incidence, supine lordosis, thoracic kyphosis, or T1SPi between stenosis groups. Despite similar supine lordosis between stenosis groups, patients with grade 2 and 3 stenosis had less standing lordosis suggesting antalgic posturing. Increasing stenotic segments did not predict worse alignment. Stenosis grading did not predict worsening PROMs.

Conclusion: Severity of lumbar stenosis as graded on MRI correlates with severity of sagittal malalignment. These findings add support to theories of sagittal malalignment as a compensatory mechanism for lumbar degenerative stenosis.

Table 1