Fluoxetine in Refractory Superior Mesenteric Artery Syndrome by Targeting Comorbid Somatic Symptom Disorder

The goal of this interventional study is to evaluate whether fluoxetine, a selective serotonin reuptake inhibitor (SSRI), can alleviate core symptoms and reduce the need for surgical intervention in patients with refractory superior mesenteric artery syndrome (SMAS) who meet diagnostic criteria for somatic symptom disorder (SSD). The main questions it aims to answer are: Can fluoxetine improve abdominal symptoms and nutritional status in patients with SMAS and comorbid SSD? Can psychiatric intervention targeting SSD reduce the likelihood of requiring duodenojejunostomy in refractory SMAS? Participants will: Receive oral fluoxetine therapy for a planned treatment duration of 6 months. Undergo baseline and follow-up assessments including symptom scoring (pain, nausea, dietary intake), body weight/BMI monitoring, and psychiatric evaluation. Complete psychological questionnaires (PHQ-15, GAD-7, PHQ-9) and resting-state fMRI at baseline and study endpoint.