1. SUPERIOR MESENTERIC ARTERY SYNDROME
Dr. ST Hung
Princess Margaret Hospital

2. History F/73 Past Health:
Metastatic CA breast ( Lung, Mediastinal LN ), on Femara® (letrozole) since 6/2012 for palliative intent
Admit for repeated bilious vomiting for days
abdominal distension
BO once every 2-3 days
Decrease intake & weight loss

3. Physical Examinations
Cachexic
Afebrile, BP/ P stable
Abdomen: grossly distended, succusion splash+, no mass or hernia
PR: No mass, brownish stool

4. AXR
Supine
Erect

5. CT abdomen & Pelvis with Contrast

7. OGD
Lateral AP

8. OGD

9. Superior Mesenteric Artery Syndrome
(SMAS)

10. Introduction
The superior mesenteric artery syndrome is defined as vascular compression of the third part of the duodenum in the angle between the aorta and the superior mesenteric artery.
First described by Austrian Professor Carl Freiherr von Rokitansky in 1842
Wilkie published the first comprehensive series of 75 patients, after which the eponym “Wilkie’s Syndrome” emerged
Other names: arteriomesenteric duodenal compression syndrome, chronic duodenal ileus and cast syndrome

11. Epidemiology
Unknown incidence; roughly estimated to be around to 0.3% in general population
Females are more commonly affected, in ratio of 3:2
About two thirds of patients are in age group between 10-39
Cases described in preterm male of 23 weeks & 86 years old man
No racial difference

12. Related Anatomy

13. Related Anatomy & Pathogenesis
Aorto-mesenteric angle ≈ 6° to 16° (Normal: 38-65°)
Aorto-mesenteric distance ≈2mm to 8mm (Normal:10-28mm)

14. Congenital Vs Acquired
Etiology
Congenital Vs Acquired

15. Etiology Congenital Causes Anatomical variants:
Short or High insertion of Ligament of Treitz
Congenital peritoneal adhesions and Ladd’s bands
Congenital low origin of the SMA
Short Mesenteric Root
Duodenal Malrotation

16. Etiology Acquired Causes Chronic Wasting Disease Trauma
e.g. Malignancy, paraplegia, AIDS
Trauma
e.g. Polytrauma, burn injury, brain and spinal cord injury
Dietary Disorders
e.g. Malabsorption syndrome, anorexia nervosa
Postoperative States
e.g. IPAA, scoliosis surgery, Cast syndrome
Local pathology
e.g. Neoplastic growth in mesenteric root, dissecting aortic aneurysm

17. Clinical Features
Depend on the cause and grade of duodenal compression
Chronic abdominal complaints with intermittent exacerbation
Rarely, rapid evolving upper intestinal ileus
Intermittent or postprandial abdominal pain (59-81%)* followed by bilious vomiting
Epigastric pain is relieved by a prone, knee-chest, left lateral decubitus position or Hayes maneuver that all reduce small bowel mesenteric tension at aortomesenteric angle
Early satiety with a sensation of fullness, food intolerance, anorexia that trigger a vicious cycle resulting in weight loss
*Ylinen P, Kinnunen J, Hockerstedt K: Superior mesenteric artery syndrome. A follow up study of 16 operated patients. J Clin Gastroenterol 1989; 11: 386–391.

18. Complications
Because of the frequent delay in the diagnosis of SMAS, it can result in life threatening complications*
Pancreatitis secondary to abnormal pancreaticoduodenal reflux within the closed intestinal loop
Gastroparesis is frequently encountered after correction surgery for SMAS
Esophageal tear
Peptic ulcer and perforation of stomach
Aspiration pneumonia, cardiovascular collapse, metabolic alkalosis, electrolyte imbalance
*M. T. Mandarry, L. Zhao, C. Zhang, Z. Q. Wei. A comprehensive review of superior mesenteric artery syndrome. Eur Surg (2010) 42/5: 229–236

19. Investigations and Diagnosis
Diagnosis is difficult and is often delayed because of incomplete obstruction and non-specific symptoms
Diagnosis by exclusion; thus requires high index of suspicious
Rosa Jimenez et al. advocated that the diagnosis should be based on clinical symptoms and radiologic evidences of obstruction*
*U¨ nal B, Aktas
A, Kemal G, et al. Superior Mesenteric artery syndrome: CT and ultrasonography findings. Diagn Interv Radiol 2005;11:90–5.

20. Investigations and Diagnosis
Radiographic criteria
Dilatation of the 1st and 2nd part of the duodenum +/- gastric dilatation
Abrupt vertical and oblique compression of the mucosal folds
Antiperistaltic flow of contrast medium (barium) proximal to obstruction, producing to and fro movements
Delay of 4 to 6 hours in gastroduodenojejunal transit time
Relief of the obstruction when the patient is placed in a prone, knee-chest or left lateral positions
Dietz UA, Debus ES, Heuko-Valiati L, Valiati W, Friesen A, Fuchs KH, Malafaia O, Thiede A: Aorto-mesenteric artery compression syndrome. Chirurg 2000; 71: 1345–1351.
Hines JR, Gore RM, Ballantyne GH: Superior mesenteric artery syndrome. Diagnostic criteria and therapeutic approaches. Am J Surg 1984; 148: 630–632.

21. Radiographic Diagnostic Tools
Plain radiograph
Conventional barium studies
Hypotonic duodenography barium study
Computed tomography (CT) scan
Conventional angiography
3-Dimensional CT angiography
Magnetic resonance angiography
Ultrasonography
Endoscopy

22. Radiographic Diagnostic Tools
Conventional barium studies
Classic diagnostic technique; cheap, easy but non-specific
A dilated proximal duodenum with an abrupt linear cut off at the 3rd part of the duodenum and a collapsed small bowel distal to the crossing SMA
Retention of barium within the duodenum
Hypotonic duodenography barium study
Duodenal peristalsis was suppressed by anti-cholinergics like propantheline bromide

23. Radiographic Diagnostic Tools
Computed tomography (CT) scan
can clearly demonstrate the aortomesenteric angle and distance accurately
the gastric and proximal duodenal dilatation, the duodenal obstruction (site of vascular compression of the duodenum)
local pathologies e.g. aneurysm or neoplasm, etc.
Provide an overall assessment of the abdominal cavity as well as the amount of retroperitoneal fat

24. Radiographic Diagnostic Tools
3-Dimensional CT & MR angiography
Most popular; rapid, non-invasive, eliminate erroneous diagnoses that originate from the angulations of SMA
Calculating the aortomesenteric angle and distance precisely
Can demonstrate the direct pressure of SMA on the entrapped duodenum
Conventional angiography
Gold standard modality in the past
Invasive, time-consuming

25. Radiographic Diagnostic Tools
Ultrasound color doppler
Advocate for detection of reduced aortomesenteric angle
Upper gastrointestinal endoscopy
To rule out intraluminal obstruction and gastric or duodenal ulcer disease that might be secondary to reflux or as a primary pathology mimicking SMAS
Fluid retention in stomach, a dilated proximal duodenum, a pulsatile mass in the third part of duodenum precluding the passage of the scope
Not indicate the diagnosis

26. Differential Diagnosis
Mechanical obstruction
e.g. Pancreatic cysts or neoplasms, paraaortic lymphadenopathy, duodenumal tumor, adhesion, malrotation and Crohn’s disease
Familial neuropathic disease
e.g. megaduodenum
Postoperative paralytic ileus
e.g. general anesthesia, analgesic, electrolyte imbalance or greater splanchnic nerve injury during anterior spinal
Recurrent biliary pancreatitis
Gastroparesis in Type I Diabetes
Psychogenic vomiting
Rare causes with decreased peristalsis
e.g. dermatomyositis, SLE, myxoedema, amyloidosis, myotonic dystrophy or chronic idiopathic intestinal pseudo-obstruction

27. Treatment
Medical Treatment to Surgical Treatment

28. Medical Treatment
In absence of displacement by an abdominal mass, an aneurysm or another pathologic condition that requires immediate surgical exploration, the treatment of the SMAS usually begins with conservative approaches
Aim: Reversal of weight loss; promote the restoration of retroperitoneal fat tissue which consequently increases the aortomesenteric angle*
*Jawad NH, Al-Sanae A, Al-Qabandi W. Superior mesenteric artery syndrome: An uncommon cause of intestinal obstruction; report of two cases and review of literature. Kuwait Med J 2006; 38:241–4.

29. Medical Treatment Nil by mouth
Nasogastric tube with regular aspiration
Correction of fluid and electrolyte balance
Enteral jejunal tube feeding, parental nutrition
Posturing maneuvers
Prokinetic drugs like metoclopramide or cisapride may be used to enhance stomach emptying by improving motility

30. Medical Treatment No clear time limit for medical treatment
Relief of symptoms has been observed from 2 to 12 days; nevertheless, it has been also reported up to 169 days* and even up to 7 months in different cases
*Lee CS, Mangla JC: Superior mesenteric artery compression syndrome. Am J Gastroenterol 1978; 70: 141–150.

31. Surgical Treatment
Indications for surgical intervention (Berner and Sherman, 1963) are:
Failed conservative treatment
Longstanding disease with progressive weight loss and duodenal dilatation with stasis
Complicated peptic ulcer disease and pancreatitis secondary to biliary stasis and reflux
Local pathology requiring laparotomy
Patients’ preference

32. Surgical Procedures Duodenojejunostomy Gastrojejunostomy
Strong’s operation
Laparoscopic duodenojejunostomy
Robotic assisted intestinal bypass surgery
Anterior transposition of the third part of duodenum
Transposition of the SMA to the infrarenal aorta
Duodenal circular drainage

33. Surgical Procedure Strong’s procedure
Mobilization of the duodenum by division of the ligament of Trietz, allowing the duodenum to fall away from the aorta
Avoids anastomosis thus, is less invasive, quicker, safer procedure, and with early postoperative recovery
Failure rate of 25%* presumably due to
Short branches of the inferior pancreaticoduodenal artery not permitting the duodenum to fall inferiorly
Adhesion resulting in difficult dissection
*Lee CS, Mangla JC: Superior mesenteric artery compression syndrome. Am J Gastroenterol 1978; 70: 141–150 .

34. Surgical Procedure Gastrojejunostomy Adequate gastric decompression
Fail to completely release duodenal obstruction leading to persistence of symptoms that necessitated duodenojejunostomy in some cases*
Persisting obstruction may lead to blind loop syndrome, gastric bile reflux and ulceration**
*Lee CS, Mangla JC: Superior mesenteric artery compression syndrome. Am J Gastroenterol 1978; 70: 141–150.
**Geer MA. Superior mesenteric artery syndrome. Mil Med 1990;155:321–323

35. Surgical Procedure Duodenojejunostomy
Was first performed by Stavely in 1910
The most frequent surgical procedure with a success rate of about 90% *
Lee and Mangla * concluded after reviewing 146 cases operated after 1963 that duodenojejunostomy revealed the best results in severe cases and was significantly better compared to gastrojejunostomy and Strong’s procedure
*Lee CS, Mangla JC: Superior mesenteric artery compression syndrome. Am J Gastroenterol
1978; 70: 141–150.

36. Surgical Procedure Laparoscopic duodenojejunostomy
Gersin and Heniford reported the first successful laparoscopic duodenojejunostomy case in 1998
Small series have reported success rates of % with laparoscopic division of the ligament of Treitz or laparoscopic duodenojejunostomy using a retrocolic stapled anastomosis.

37. Surgical Procedure Others
World’s first robotically assisted intestinal bypass surgery for SMAS: was reported in July 2008 at London Health Services Centre
Anterior transposition of the third part of duodenum
Billroth II gastrectomy
Transposition of the SMA to the infrarenal aorta
Duodenal circular drainage

38. Conclusion
SMAS is a very rare entity which has been associated with a wide range of predisposing factors, presenting with features of upper GIT obstruction and a recent abrupt weight loss.
An early recognition of the condition, institution of the appropriate conservative measures and proper timely selection of a definite surgical method are critical to prevent the development of severe complications.
M. T. Mandarry et al. A comprehensive review of superior mesenteric artery syndrome. Eur Surg (2010) 42/5: 229–236

39. Thank You