Superior Mesenteric Artery Syndrome (SMA Syndrome) Surgery

Superior mesenteric artery (SMA) syndrome is a rare and frequently missed cause of upper intestinal blockage. The third part of the duodenum normally passes between the aorta and the superior mesenteric artery, cushioned by a pad of fat.

When that fat pad shrinks, usually after significant weight loss, the angle between the two arteries narrows and pinches the duodenum. The result is a cycle of pain after eating, nausea, vomiting, and further weight loss (Maria et al., Journal of Gastrointestinal Surgery, 2026).

• How rare: SMA syndrome affects an estimated 0.01% to 0.3% of people.

• Who it affects: most often women aged 10–39 (Saylors and St Peter, Journal of Laparoendoscopic & Advanced Surgical Techniques, 2026).
• Common triggers:
  • Eating disorders, cancer, trauma, and burns (Kirby et al., Annals of the Royal College of Surgeons of England, 2017)
  • Scoliosis surgery (Pappalardo et al., European Journal of Medical Research, 2024)
  • Rapid weight loss after bariatric surgery (Mitchell et al., Obesity Surgery, 2026)
  • Median arcuate ligament syndrome (MALS), which causes profound weight loss of its own (Lozano et al., Surgical Endoscopy, 2026)

Treatment starts with nutrition, to rebuild the fat pad. When nutritional therapy fails, surgery provides durable relief. Duodenojejunostomy, a bypass that connects the dilated duodenum directly to the jejunum beyond the compression, is the preferred operation (Maria et al., Journal of Gastrointestinal Surgery, 2026).

Our practice is a regional referral center for abdominal vascular compression syndromes, including SMA syndrome, Median Arcuate Ligament Syndrome, and Nutcracker Syndrome. We offer laparoscopic, robotic, and magnetic duodenojejunostomy.

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• The anatomy:
  • The normal angle between the aorta and the SMA is 38°–65° (Saylors and St Peter, Journal of Laparoendoscopic & Advanced Surgical Techniques, 2026).
  • In SMA syndrome, the angle narrows to less than 22–25°, and the distance between the vessels falls to less than 8–10 mm. The duodenum gets trapped (Maria et al., Journal of Gastrointestinal Surgery, 2026; Koshy et al., Abdominal Radiology, 2024).

• The bypass: duodenojejunostomy creates a new opening between the dilated duodenum (before the blockage) and the jejunum (after it). Food and digestive juices flow around the compression instead of through it.
• Why bypass instead of release:
  • Strong's procedure divides the ligament of Treitz to let the duodenum drop away from the artery. It avoids a bowel connection but has a symptomatic failure rate of up to 25% (Chang et al., Surgical Endoscopy, 2017).
  • Gastrojejunostomy doesn't drain the trapped duodenum and can cause blind loop syndrome and ulcers, so it has largely been abandoned (Chang et al., Surgical Endoscopy, 2017; Shen et al., Obesity Surgery, 2023).

Magnetic Duodenojejunostomy: A New Approach Developed by Our Team

Dr. de la Cruz-Muñoz and his team developed a new way to perform magnetic duodenojejunostomy using a direct entry approach. The duodenum is connected to the jejunum without sutures or staples at the anastomosis. We believe it represents a step forward in SMA syndrome treatment: the operation is quicker and technically easier to perform, and it is designed to lower the risk of problems at the anastomosis.

How it works:

• Two magnets are positioned, one in the duodenum above the compression and one in the adjacent jejunum, using endoscopic and laparoscopic guidance.

• The magnets attract through the bowel walls, compressing the tissue between them.

• Over the following days to weeks, the compressed tissue heals around the edges and the center separates, forming a smooth, natural-looking connection.

• The joined magnets then pass harmlessly in the stool.

Why it matters:

• No staples or sutures left at the connection. Conventional anastomoses leave staples and sutures that act as foreign bodies in the bowel. A magnetic anastomosis leaves no permanent implant that can contribute to inflammation, scarring, or stricture (Olavarria et al., Surgical Endoscopy, 2025).
• An excellent safety record so far in bariatric surgery. The same magnetic technology has been used for duodeno-ileostomy (MagDI):
  • 43 patients: no anastomotic leaks, bleeding, obstruction, infection, or device-related deaths, and the anastomosis was patent in 100% (Gagner et al., Surgery for Obesity and Related Diseases, 2024).
  • A 24-patient revisional series: again 0% leak, bleeding, or reintervention at 1 year (Gagner et al., World Journal of Surgery, 2024).

• Faster. In early MagDI experience, the anastomosis itself took about 14–17 minutes to create (Nassar et al., Obesity Surgery, 2026).

• Stronger healing in laboratory studies. Magnetic anastomoses showed higher burst pressure, less adhesion formation, and more orderly tissue healing than stapled or sewn connections (Olavarria et al., Surgical Endoscopy, 2025; Xu et al., Scientific Reports, 2026).

• Well suited to SMA syndrome patients. Many arrive malnourished, with fragile tissue and a dilated, thin-walled duodenum. A simpler, staple-free anastomosis can make the operation less demanding for the patient.

Magnetic duodenojejunostomy is a new technique. Published long-term outcome data specific to SMA syndrome are not yet available. Each patient is counseled on whether magnetic or conventional duodenojejunostomy is the better fit.

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• High success rates:
  • Minimally invasive duodenojejunostomy relieves symptoms in more than 90% of patients, with a complication rate of about 7% (Jain et al., Surgical Endoscopy, 2021).
  • After bariatric surgery: 95% of patients had complete resolution, with no SMA syndrome-related deaths and no recurrences during follow-up (Mitchell et al., Obesity Surgery, 2026).

• Durable relief. Duodenojejunostomy provides lasting symptom relief and significantly improves quality of life (Maria et al., Journal of Gastrointestinal Surgery, 2026).
• Less invasive:
  • Shorter hospital stays, less pain, fewer wound infections, and lower cost than open surgery (Jain et al., Surgical Endoscopy, 2021).
  • Median operating time of 98 minutes and hospital stay of 3 days in one long-term laparoscopic series (Cienfuegos et al., World Journal of Surgery, 2020).

• Freedom from feeding tubes and IV nutrition. Patients can eat by mouth again and rebuild weight naturally.

• Magnetic option for a sutureless, staple-free anastomosis designed to reduce leak and stricture risk.

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• Confirmed SMA syndrome, with compatible symptoms plus imaging findings:
  • Aortomesenteric angle under 22–25°
  • Aortomesenteric distance under 8–10 mm
  • Dilated stomach and duodenum above the compression (Manuel Rafael et al., Abdominal Radiology, 2026)

• Failure of nutritional therapy, including nasojejunal or jejunostomy feeding, or parenteral nutrition (Shen et al., Obesity Surgery, 2023).

• Patients who need a durable solution after long periods of tube or IV feeding, or who have recurring electrolyte problems (Shen et al., Obesity Surgery, 2023).

• SMA syndrome after bariatric surgery. 85% of these patients ultimately required surgery (Mitchell et al., Obesity Surgery, 2026).

• SMA syndrome with MALS. Some patients need both conditions treated, sometimes in the same operation (Cienfuegos et al., World Journal of Surgery, 2020).

• Other causes ruled out first, especially gastroparesis and other motility disorders, which can mimic SMA syndrome (Cienfuegos et al., World Journal of Surgery, 2020).

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1. General anesthesia with a minimally invasive approach (laparoscopic or robotic) through several small incisions.
2. Exposure of the duodenum. The colon is lifted to expose the dilated third portion of the duodenum to the right of the superior mesenteric vessels.
3. Selection of a jejunal loop a short distance beyond the ligament of Treitz that reaches the duodenum without tension.
4. Creation of the anastomosis, by one of two methods:
   • Conventional: a side-to-side stapled anastomosis, typically about 40 mm wide, with closure of the openings. A calibrated, uniform stapled anastomosis may reduce stricture risk compared with a non-calibrated hand-sewn connection (Sun et al., Surgical Endoscopy, 2015).
   • Magnetic: two magnets are positioned in the duodenum and jejunum and coupled, beginning gradual compression and formation of the connection without sutures or staples.
5. Testing and inspection for bleeding and leaks.
6. Concurrent procedures when indicated, such as median arcuate ligament release for coexisting MALS (Cienfuegos et al., World Journal of Surgery, 2020).

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• Anastomotic leak or bleeding. These are uncommon. The magnetic technique is designed specifically to minimize them.

• Anastomotic stricture. It is usually treatable with endoscopic balloon dilation (Sun et al., Surgical Endoscopy, 2015).

• Delayed gastric emptying. It is the most common early issue, especially in patients who were depleted for a long time before surgery, and usually resolves (Jain et al., Surgical Endoscopy, 2021).

• Persistent nausea from chronic stomach dysmotility after long-standing obstruction (Maria et al., Journal of Gastrointestinal Surgery, 2026).

• Blind loop syndrome, a theoretical risk of bypassing a short segment of duodenum (Sun et al., Surgical Endoscopy, 2015).

• Incomplete symptom relief. A systematic review reported a 21% failure-to-treat rate after SMA syndrome surgery. That figure underscores how much careful patient selection and complete workup matter (Jonas et al., Langenbeck's Archives of Surgery, 2023).

• Magnetic-specific considerations: magnet passage is monitored with imaging. Patients with magnets in place must avoid MRI until the magnets have passed.

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• Hospital stay: typically 1–3 days after minimally invasive surgery (Cienfuegos et al., World Journal of Surgery, 2020). It can be longer in severely malnourished patients, who need more time to optimize (Jain et al., Surgical Endoscopy, 2021).

• Diet progression: from clear liquids to small, frequent, high-calorie meals.

• After magnetic duodenojejunostomy: the connection forms gradually, so our team tailors the diet and confirms the anastomosis with imaging before advancing.

• Return to light activity: within days.

• Return to work or school: 1–3 weeks.

• Nutritional rehabilitation continues for months. Weight regain restores the mesenteric fat pad and further protects against recurrence.

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• Most patients do well long term:
  • After 94 months of median follow-up, 61.5% had excellent results. Most poor outcomes were linked to underlying gastric emptying disorders (Cienfuegos et al., World Journal of Surgery, 2020).
  • At a median of 5.3 years after laparoscopic duodenojejunostomy, abdominal pain, nausea, and weight loss were significantly reduced compared with before surgery (Wills et al., Surgical Endoscopy, 2025).

• Some symptoms may persist when motility disorders, psychological conditions, or other abdominal disorders coexist. That's why thorough evaluation before surgery matters (Sun et al., Surgical Endoscopy, 2015).

• Weight restoration and freedom from feeding tubes are realistic goals for most patients.

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More in General and Minimally Invasive Surgery

Related procedures: Median Arcuate Ligament Release, Major Surgical Oncology and Complex Benign Tumor Surgery, Robotic Surgery, Laparoscopic Cholecystectomy, Hernia Repair, Inguinal Hernia Repair. For an overview of all options, see Minimally Invasive Surgery.

Conditions treated: SMA Syndrome, Duodenal Obstruction, Median Arcuate Ligament Syndrome (MALS), Malnutrition.

Health Improvements

• Correction of dehydration and electrolyte abnormalities. Recurrent vomiting can cause low potassium and metabolic alkalosis (Pappalardo et al., European Journal of Medical Research, 2024).

• Recovery from protein-calorie malnutrition, with improving albumin, vitamins, and minerals.

• Reduced risk of aspiration pneumonia and other dangerous complications of chronic vomiting (Pappalardo et al., European Journal of Medical Research, 2024).

• Freedom from parenteral nutrition and its line infection and liver risks.

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Preventing Recurrence

• Structured nutrition follow-up until a healthy, stable weight is reached.

• Treating the underlying trigger: eating disorders, MALS, malabsorption, or prior bariatric anatomy.

• Behavioral health support when needed. In one series, all patients with persistent long-term symptoms had preexisting psychological conditions (Sun et al., Surgical Endoscopy, 2015).

• Imaging or endoscopy if symptoms return, to check the anastomosis.

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Dr. Nestor de la Cruz-Muñoz, MD, FACS, DABOM leads a regional referral center for abdominal vascular compression syndromes. He treats some of the most complex SMA syndrome and MALS patients in the region.

• An innovator in SMA syndrome surgery. He and his team developed a magnetic duodenojejunostomy technique. It brings sutureless, staple-free magnetic compression anastomosis to SMA syndrome, making the operation quicker and easier to perform and designed to reduce anastomotic risk.
• Vascular compression expertise:
  • He was the first surgeon in Florida to perform minimally invasive median arcuate ligament release.
  • He has presented his surgical techniques to colleagues.
  • SMA syndrome and MALS frequently overlap. In one 100-patient series, 19% of MALS patients developed SMA syndrome after profound weight loss (Lozano et al., Surgical Endoscopy, 2026). He recognizes and treats both.

• Magnetic anastomosis experience. He uses magnetic anastomosis technology across MagDI, Gastric Outlet Obstruction Surgery, and now SMA Syndrome Surgery.

• Educator of surgeons. He served for 10 years as a surgical fellowship program director, training surgeons in advanced minimally invasive foregut and bariatric surgery.

• Complete foregut and bariatric expertise. That includes SMA syndrome after bariatric surgery, where he can also evaluate Gastric Bypass Reversal for Excessive Weight Loss or Gastric Bypass Reversal for Malnutrition when they're needed.

• Multidisciplinary care with nutrition, gastroenterology, radiology, and behavioral health to rebuild weight and address every contributor to symptoms.

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Treating SMA syndrome surgically calls for broad minimally invasive experience. Dr. de la Cruz-Muñoz has performed over 15,000 such procedures across over 25 years, ranging from complex foregut and abdominal operations to hernia, gallbladder and bariatric surgery.

• Chronic vomiting and a dilated stomach can worsen reflux and esophageal irritation.

• Relieving the obstruction often improves reflux symptoms.

• Persistent reflux after surgery is evaluated separately. See GERD / Acid Reflux and Hiatal Hernia Repair.

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• Anastomotic stricture: Endoscopic balloon dilation, often successful (Sun et al., Surgical Endoscopy, 2015).
• Recurrent or persistent symptoms:
  • Gastric emptying studies to identify gastroparesis.
  • Rarely, distal gastrectomy with Roux-en-Y reconstruction. In one long-term series, a patient whose symptoms returned 4 years after duodenojejunostomy went on to distal gastrectomy (Cienfuegos et al., World Journal of Surgery, 2020).

• Failed Strong's procedure: conversion to duodenojejunostomy. In one bariatric series, a patient with persistent symptoms after ligament of Treitz release later required duodenojejunostomy (Mitchell et al., Obesity Surgery, 2026).

• SMA syndrome after bariatric surgery: revision of the bariatric anatomy when appropriate (Mitchell et al., Obesity Surgery, 2026).

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• SMA syndrome surgery is a medically necessary operation for a mechanical obstruction and is generally covered by commercial insurance and Medicare.
• Documentation typically includes:
  • CT angiography showing the narrowed angle and distance
  • Upper GI contrast study
  • Records of failed nutritional therapy
  • Weight history

• Prior authorization is usually required.

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• Confirmation of the diagnosis:
  • CT angiography (CTA), the gold standard
  • Upper GI contrast study showing duodenal dilation with an abrupt cutoff at the third portion (Pappalardo et al., European Journal of Medical Research, 2024)
• Ruling out mimics:
  • Upper endoscopy
  • Gastric emptying study
  • Evaluation for MALS and nutcracker syndrome. Up to one-third of SMA syndrome patients have concurrent left renal vein compression (Manuel Rafael et al., Abdominal Radiology, 2026).
• Nutritional optimization:
  • Nasojejunal feeding or parenteral nutrition when needed
  • Correction of electrolytes

• Multidisciplinary review, including behavioral health when appropriate (Sun et al., Surgical Endoscopy, 2015).

• GLP-1 medications are managed as directed by the anesthesia team.

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• Stage 1: clear liquids after surgery.

• Stage 2: full liquids and protein shakes.

• Stage 3: soft, high-calorie, high-protein foods.

• Stage 4: a regular diet in small, frequent meals, 5–6 per day.

• Calorie-dense additions: nut butters, healthy oils, full-fat dairy if tolerated.

• Feeding tubes are weaned as oral intake improves.

• Dietitian visits at every stage.

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Weight Restoration After Surgery

• The goal is weight gain, not weight loss.

• Most patients gain weight steadily after surgery once they can eat without obstruction.

• Weight regain rebuilds the protective mesenteric fat pad.

• Time to symptom resolution: a median of 12.5 months among patients with SMA syndrome after bariatric surgery (Mitchell et al., Obesity Surgery, 2026).

• A personalized target weight is set with our dietitians.

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Rebuilding Muscle

• SMA syndrome patients are often severely depleted of muscle as well as fat.

• Body composition testing (InBody or DEXA) tracks rebuilding of lean mass, not just weight.

• High-protein, high-calorie nutrition with supplements as needed.

• Progressive resistance training once healed, to rebuild strength and function.

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• Walk the day of surgery.

• Weeks 1–4: daily walking. No lifting over 15–20 lbs.

• After 4–6 weeks: a gradual return to resistance training, prioritizing muscle rebuilding.

• Activity is matched to nutritional recovery, so patients aren't burning more calories than they can take in.

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SMA syndrome is uncommon, and many patients travel for diagnosis and treatment. Patients are often malnourished, so nutritional support may begin before surgery. Plan on one to two weeks in Miami, and bring CT angiography images and nutrition records.