The goal of this clinical trial is to find out which surgery works better to treat people with a rare condition called Superior Mesenteric Artery Syndrome (SMAS). This condition causes the duodenum to be squeezed between two arteries, leading to severe nausea, vomiting, and weight loss. The researchers are comparing two types of surgery:

• One Anastomosis Gastric Bypass (OAGB)
• Duodeno-jejunostomy (DJ)

The main questions this study will answer are:

• Which surgery improves symptoms and nutritional status better?
• Which surgery leads to fewer complications and better quality of life?

Participants will:

• Be randomly assigned to one of the two surgeries
• Be followed for 12 months after the operation
• Complete follow-up visits and nutritional assessments
• Answer questions about their symptoms and overall well-being

Superior Mesenteric Artery Syndrome (SMAS) is a rare but serious condition where part of the small intestine (the duodenum) gets compressed between major blood vessels. This can cause severe digestive symptoms and weight loss. Surgery is often needed when other treatments do not work.

This prospective randomized controlled trial compares two surgical options to relieve the compression: One Anastomosis Gastric Bypass (OAGB) and Duodeno-jejunostomy (DJ). Both surgeries aim to improve food passage and relieve symptoms, but they work differently and have different effects on digestion and nutrition.

Participants will be randomly assigned to one of the two surgical procedures. The study will collect data before and after surgery on symptoms, nutritional status, complications, and quality of life. Follow-up will continue for 12 months.

The goal is to help surgeons and patients choose the most effective and safest surgical treatment for SMAS.

Inclusion Criteria:

• Clinical diagnosis of Superior Mesenteric Artery Syndrome (SMAS) based on symptoms and radiologic findings
• No prior gastric or intestinal surgery
• Willingness and ability to participate in follow-up for 12 months

Exclusion Criteria:

• Presence of other gastrointestinal pathologies mimicking SMAS
• Severe comorbidities contraindicating surgery (e.g., advanced cardiac or pulmonary disease)
• History of previous bariatric or upper GI surgery
• Refusal or inability to provide informed consent

De-identified individual participant data (IPD) related to primary and secondary outcome measures will be available to researchers upon reasonable request after the study is published. Data sharing will be considered for academic and clinical research purposes.

Starting 3 months after publication of the primary results and for up to 3 years after publication

De-identified individual participant data (IPD) and supporting documents such as the study protocol and statistical analysis plan will be available to qualified researchers, academic institutions, or healthcare professionals. These individuals must submit a written request with a sound scientific rationale for secondary analysis. Access will be granted at the discretion of the principal investigator. Approved users must sign a data use agreement to ensure confidentiality and appropriate use. All requests should be sent to the principal investigator's official institutional email address.