Association between anatomical subtypes of medullary infarction and clinical outcome: a multicenter cohort study

This multicenter, large-sample retrospective cohort study aimed to investigate the clinical characteristics, early neurological deterioration (END), clinical outcome, and prognostic factors among seven anatomical subtypes of acute medullary infarction, and to examine whether anatomical classification provided independent prognostic value beyond baseline neurological severity.

From January 2019 to October 2024, 352 patients with acute medullary infarction from three centers (the First Affiliated Hospital of Kunming Medical University, West China Hospital of Sichuan University, and Peking University First Hospital Taiyuan Hospital) were enrolled. Based on axial magnetic resonance imaging-diffusion weighted imaging findings, patients were classified into seven anatomical subtypes: lateral medullary infarction (LMI) subtypes (superficial lateral, dorsolateral, oblique lateral, and dorsal types) and medial medullary infarction (MMI) subtypes (ventromedial, centromedial, and dorsomedial types). We compared clinical manifestations, complications, END (defined as an increase in NIHSS score ≥4 points or death), and 90-day functional outcomes (modified Rankin Scale, mRS) among different subtypes. Multivariate logistic regression analysis was performed to identify independent predictors of favorable outcomes (mRS ≤ 2).

Among 352 patients, the most prevalent subtypes were dorsolateral (29.8%), superficial lateral (18.8%), and dorsal (16.5%). Significant heterogeneity was observed in clinical manifestations and END, with the dorsomedial subtype demonstrating the highest rates of limb motor dysfunction (65%), consciousness disturbance (27.5%), and END (25.0%). Regarding 90-day outcomes, the dorsomedial subtype had highest rate of poor favorable outcomes (65%), while the oblique lateral subtype had lowest rate of poor favorable outcomes (16.7%). The admission NIHSS score, age, dysphagia, contralateral limb involvement, and large-artery atherosclerosis were independent predictors of 90-day functional outcomes.

This study demonstrated significant heterogeneity in clinical characteristics and 90-day outcomes among the seven anatomical subtypes of medullary infarction. The certain subtypes (particularly the dorsomedial subtype) were associated with higher rates of early neurological deterioration and poor functional outcomes.