Erector Spinae Degeneration and Gait in NPH: An MRI-Based Retrospective Study.

Abstract

Normal pressure hydrocephalus (NPH) is a reversible condition characterized by gait disturbance, cognitive decline, and urinary incontinence. While shunt surgery often improves gait, postoperative (PostOP) recovery varies, suggesting that factors beyond cerebrospinal fluid dynamics may affect outcomes. Therefore, this study aims to evaluate whether preoperative paraspinal muscle degeneration predicts gait function in patients with NPH before and after surgery. We retrospectively reviewed 33 patients with lumboperitoneal shunts who were followed for ≥12 months. Preoperative L3-level T2-weighted magnetic resonance imaging was used to assess total and lean cross-sectional area (CSA) and fatty infiltration of the psoas major, quadratus lumborum, spinotransverse, and erector spinae muscles. Gait was measured using the Timed Up and Go test, 10-m walk speed, and modified Rankin Scale. Greater fatty infiltration (β = -0.255, P = 0.015) and smaller lean erector spinae CSA (β = -0.394, P = 0.022) were associated with poorer preoperative Timed Up and Go (TUG) performance. Smaller lean CSA also correlated with higher modified Rankin Scale scores (β = -0.123, P = 0.008). At 12 months, lean CSA predicted TUG performance but not functional outcome changes. Preoperative erector spinae degeneration correlates with reduced baseline mobility in NPH but does not predict PostOP improvement, though it may indicate lower functional status.