Superior mesenteric artery syndrome(SMA syndrome)

Joint hospital surgical grandround 19/7/2014

Cheung Hing Fong

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Case presentation 41/F Phx

Scoliosis with OT done >20years ago SMA syndrome diagnosed in 2011, on

conservative treatment c/o: increased vomiting and weight loss for 3

months In hospital care for dehydration PE: thin body build, BMI 15

CTA 10/2013: narrowed aortomesenteric angle(~16*) and distance (5mm) with compression over third part of duodenum and left renal vein

CTA: dilated left ovarian veins and pelvic side veins, compatible with Nutcracker syndromeDx: SMA and nutcracker syndrome

Infrarenal SMA transposition

Repeated vomiting early post OT

Recovered gradually and tolerated normal diet

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Pathophysiology

Vascular compression of third part of duodenum(D3) by angle formed by SMA and aorta (aortomesenteric angle)

Third part of duodenum

SMA syndrome

Left renal vein

Nutcracker syndrome

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Predisposing conditions

1. loss of aortomesenteric fat (catabolic state)

2. Post operative state ileoanal pouch bariatric surgery e.g lap roux en Y gastric bypass spinal surgery

3. local pathology abdominal aortic aneurysm

Ligament of Treitz

Predisposing conditions(local anatomy)

low origin of SMA high or short

insertion of ligament of Treitz cranial

displacement of duodenum

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Post-prandial epigastric pain then bilious vomiting

with prone/ knee chest/ left lateral position

Food fear weight loss and anorexia

Patient presentation

Diagnosis is usually delayed Rare disease

Diseases with similar presentation anorexia duodenal/ pancreatic tumour irritable bowel syndrome megaduodenum

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Management

8. Summary

Epidemiology

Prevalence: 0.01-0.3% (1 in 330-7690)

More affected female age 10-39 chronic illness

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Investigations

Barium studyCT angiogram (abdomen)Upper endoscopy+/- EUS

Barium study 1. dilatation of D1 and D2 +/- gastric dilatation 2. abrupt vertical and oblique compression of

mucosal folds 3. antiperistaltic flow of contrast proximal to

the obstruction 4. delay in transit of 4-6hours through the

gastroduodenal region 5. relief of obstruction in prone, knee-chest or

left lateral decubitus position

CT finding Aortomesenteric angle <22-25*

(43% sensitivity, 100% specificity)

Aortomesenteric distance <8mm (100% sensitivity and specificity) for at least one symptom of SMA syndrome respectively

Rule out other causes of compression E.g. neoplasia or aneurysm or annular

pancreas

Proximal gastroduodenal dilatation

Endoscopy finding pulsatile D3 obstruction proximal duodenal dilatation gastric retention with reflux

esophagitis

Rule out structural lesion

EUS: similar finding and demonstrate loss of aortomesenteric fat

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Treatment

***medical treatment*** Gastroduodenal decompression Correction of fluid and electrolyte Nutritional support

High caloric enteral nutrition via feeding tube (jejunum)

Parenteral nutrition

Positive response: 83% (majority)

Surgery is only indicated when medical treatment failUsually for patients with chronic

course (persistent symptom/ deterioration after medical treatment)

No clear time limit

Surgery

Gastrointestinal

Vascular

Type

Approach

bypass

open

lap

Infrarenal SMA transposition

Strong’s OT

Others

Gastrojejunostomy

Duodenojejunostomy

Anterior transposition of D3

Roux en Y duodenojejunal Bypass

Duodenal circular drainage

Duodenojejunostomy(DJ)

Side to side anastomosis between dilated proximal duodenum and jejunum

Strong’s procedure

division of ligament of Treitz duodenum was separated from pancreas

and posterior retroperitoneal attachment D4 became intra-peritoneal structure caudal displacement of duodenum

away from the aortomesenteric angle

DJPros Success rate 80-90%

Cons Blind loop (modification: division of 4th part of duodenum; to eliminate blind loop)

Most frequently performedSuperior result than GJ and strong’s OT

DJ GJPros Success rate 80-

90%Common GI procedure

Cons Blind loop (modification: division of 4th part of duodenum; to eliminate blind loop)

Fail to relieve duodenal obstructionbile reflux, peptic ulcer and blind loopSome need further OT, DJ

Most frequently performedSuperior result than GJ and strong’s OT

Severe dilated stomach and duodenumDuodenal ulcer

DJ GJ Strong’s OTPros Success rate 80-

90%Common GI procedure

No anastomosis Less invasiveOT time decreasedFaster recovery

Cons Blind loop (modification: division of 4th part of duodenum; to eliminate blind loop)

Fail to relieve duodenal obstructionbile reflux, peptic ulcer and blind loopSome need further OT, DJ

-adhesion

-branches of inferior pancreatico-duodenal artery

25% fail to achieve caudal displacement of duodenum

Most frequently performedSuperior result than GJ and strong’s OT

Severe dilated stomach and duodenumDuodenal ulcer

Limited by local anatomy

Laparoscopic approach Both DJ and Strong’s OT reported to be done

under laparoscopic approach

Lap DJ systematic review of 9 papers; total 13 cases Length of stay 4.5days10 days (open DJ) 1 case(7%) trocar site bleeding reoperation no case in open approach need reoperation

Vascular surgery--Infrarenal SMA transposition A therapeutic procedure for chronic

mesenteric ischemia

Not a common surgery for SMA syndrome

caudal transposition of compressing SMA to infrarenal aorta compression over D3

Infrarenal transposition of SMA Omentum and

transverse colon retracted cranially

SB retracted to right

Division of ligament of Treitz and mobilize D4 and DJ flexure to right

Infrarenal transposition of SMA Infrarenal aorta

cross clamp after iv heparin

End to side anastomosis between SMA and infrarenal aorta with 5/0 prolene

Far less common than GI surgery Only one case report (Germany)

data regarding its outcome not available Merit

no bowel anastomosis treat concomitant Nutcracker syndrome

Higher risk compared with GI surgery Anastomotic break downBleeding Bowel ischemia Embolism

Infrarenal transposition of SMA

In the case presented Before proceed to SMA transposition Other alternatives: conservative, GI bypass

and left renal vein stenting

She opted for SMA transposition GI complications like bowel anastomotic

leaks, blind loop syndrome treat both SMA and Nutcracker

syndrome by a single operation

Despite surgery

Small number--developed persistent symptom after surgery

Postulations duodenal atony after massive dilatation strong reverse peristalsis after prolong

obstruction

1. Case presentation

2. Pathophysiology

3. Predisposing conditions

4. Presentation

5. Epidemiology

6. Diagnosis and imaging finding

7. Treatment

8. Summary

Points to note

Diagnosis not to missVicious cycle starving

Different treatment options Depend on patients’ condition Selection of optimal treatment

First line: Medical treatment GI bypass surgery—DJ

unless with DU

Strong’s OT: mainly pediatric patients Likely due to congenital anatomic

predispositon High risk of failure(1/4)

Phx surgery of upper abd (e.g. bariatric surgery) due to adhesion

END