Outcome of Surgery to Improve Swallowing in Patients with Lateral Medullary Syndrome: A Retrospective Cohort Study

The study investigated surgical interventions to improve dysphagia in patients with lateral medullary syndrome (LMS), along with optimal scheduling of surgery and prognostic factors. In this retrospective, single-center cohort study, dysphagia patients with LMS who underwent surgery between January 2010 and December 2021 were enrolled. The National Outcomes Measurement System (NOMS) was used to classify swallowing function (level 1: only tube feeding, level 5: without tube feeding). Patients were divided into four groups. Groups 1 and 2, LMS onset within 1 year, and groups 3 and 4, onset after 1 year. Groups 1 and 3 had infarctions confined to the oblongata. Groups 2 and 4 had infarctions extending to the cerebellum. The primary outcome was the time to achieve NOMS >= 5. The final NOMS level and pathological findings were considered. Nineteen cases were included. Group 4 comprised one case and was excluded. The mean overall preoperative NOMS was 1.11. The mean time to NOMS >= 5 was 9.6 months (95% confidence interval: 5.04-14.2), and that to NOMS >= 5 was 1.67 (1.07-2.26), 11.4 (4.71-18.1), and 7.6 (5.15-10.1) months for groups 1, 2, and 3, respectively. Group 1 achieved NOMS >= 5 earlier than groups 2 and 3 (P = 0.01 and 0.03, respectively). The overall final NOMS value was 4.68. Fourteen patients had atrophy or fibrosis of the cricopharyngeal muscle. In conclusion, surgery was effective for effective for treating dysphagia in LMS patients. However, improvement is prolonged if > 1 year has passed since onset or the infarction extended to the cerebellum.