1. 上海交通大学医学院附属瑞金医院普外科

2. Anatomy The jejunal mucosa is relatively thick with prominent plicae circulares; the mesenteric vessels form only one or two arcades with long vasa recta. The ileum is smaller in circumference and has thinner walls; the mesenteric vessels form multiple vascular arcades with short vasa recta.

3. Blood supply to the jejunoileum and distal duodenum is entirely from the superior mesenteric artery, which courses anterior to the third portion of the duodenum. The celiac artery supplies the proximal duodenum.

4. Physiology

5. Motility: Peristalsis consists of intestinal contractions passing aborally at a rate of 1 to 2 cm/sec contractions initiated by the migrating myoelectric complex (MMC) under the control of both neural and humoral pathways

6. ENDOCRINE FUNCTION

7. Obstruction Etiology: Common causes of small bowel obstruction in industrialized countries:

8. Clinical Manifestations and Diagnosis Cardinal symptoms: colicky abdominal pain nausea vomiting abdominal distention failure to pass flatus and feces

9. Physical Exam distended abdomen peristaltic waves minimal or no bowel sounds Mild abdominal tenderness with / without a palpable mass Exam to rule out incarcerated hernias Rectal exam

10. Radiologic and Laboratory Examinations Plain abdominal radiographs: accuracy≈60% - dilated loops of small intestine without evidence of colonic distention -multiple air-fluid levels, often in a stepwise pattern -demonstrate the cause of the obstruction CT: for more complex cases

12. Plain abdominal film shows complete bowel obstruction caused by a large radiopaque gallstone (arrow) obstructing the distal ileum.

13. CT scan of the abdomen of a patient with a mechanical bowel obstruction secondary to an abscess in the right lower quadrant (arrow). Multiple dilated and fluid-filled loops of small bowel are noted.

14. Simple Vs Strangulating Obstruction “Classic” signs of strangulation: -tachycardia -fever -Leukocytosis -a constant, noncramping abdominal pain

15. Differentiation of partial from complete SBO Partial SBO: pass flatus or liquid stools Complete SBO: obstipation

16. Differentiation of Proximal / distal SBO pain: epigastric / periumbilical area vomiting: prominent / later onset distention: no / predominate

17. Treatment Medical and surgical management The overlapping sequence :investigation resuscitation operation The timing of operation depends on three factors: -duration -opportunity of vital organ function -risk of strangulation

18. Medical Management Nasointestinal /nasogastric intubation Intravenous fluids /blood plasma administration Broad-spectrum antibiotics administration

19. Surgical principles The nature of problem determines approach to management of SBO. The criteria of determining bowel viability: color, motility, arterial pulsation If questionable, released and placed,re- examined