ADHESIVE small bowel obstruction

1. Leslie Kobayashi Trauma Conference 2013 ADHESIVE small bowel obstruction

2. Overview • Background • Pathophysiology/Etiology • Diagnosis • Treatment • Outcomes

3. Small bowel obstruction (SBO) • Mechanical obstruction of the small bowel preventing free passage of intraluminal material • May be due to: • Bowel wall inflammation, edema or tumor • Intraluminal obstruction (bezoar, gallstone, foreign body) • Extrinsic compression (adhesion, hernia, tumor, volvulus)

4. Background • Obstruction is the most common small bowel pathology requiring surgical consultation • Accounts for 20% of acute surgical admissions • Costs $800 million annually

5. Background • Most common causes of SBO • Adhesive 60-75% • Malignancies 9-11% • Hernias 8-18% • IBD 5%

6. SBO in the virgin abdomen • Historically • Primary causes: hernia and volvulus • Currently • Primary causes: malignancy, IBD • All cases of SBO in a virgin abdomen should be taken for operative exploration due to high failure rate of NOM and concern for malignancy

7. Adhesive SBO

8. Pathophysiology Peritoneal Damage • Adhesions are fibrous bands of connective tissue that form in response to trauma, surgical manipulation, or inflammation Bleeding Inflammation Fibrinogen Stable Fibrin matrix Capillaries & Migration of Fibroblasts Adhesion Barmparas et al, J Gastrointest Surg 2010

9. Pathophysiology • Postmortem study • Minor procedure: 51% had adhesions • Major procedure: 72% had adhesions • Multiple operations: 93% had adhesions • 93% of 210 patients with abdominal procedures, had intra-abdominal adhesions at re-laparotomy. Weibel MA. Am J Surg 1973 Menzies D. Ann R Coll Surg Engl 1990

10. Risk factors for SBO • Age • Comorbid conditions • Prior surgery • Stepwise increase with number of prior procedures • Surgical technique • Open technique associated with significantly higher rates of SBO • Risk increased 2-8x’s

11. Procedure related risk Barmparas et al, J Gastrointest Surg 2010

12. Trends over time? • ↓risk of SBO with laparoscopy compared to open • Laparoscopy rate ↑over time • Has this resulted in ↓rate of SBO? • No Scott, et al Am J Surg 2012 and Angenete, et al Arch Surg 2012

13. Etiology • Overall incidence of SBO 4.6% • Top operations leading to SBO • Appendectomy 14-30% • Colorectal 21-34% • Gynecological surgery 12-28%

14. Diagnosis

15. Diagnosis: Clinical presentation • Anorexia, nausea, vomiting, obstipation (90%), constipation (80%), abdominal pain • Abdominal distension, high pitched bowel sounds, tympany, TTP, feculant NGT output/vomitus • Hypocholoremic, hypokalemic metabolic alkalosis

16. Diagnosis: Radiology findings • Plain films • Benefits: rapid, repeatable, no contrast required, patient does not have to be supine for prolonged time period, can be done at bedside

17. Diagnosis: Radiology findings • Findings: • Distended loops of bowel • Air-fluid levels • Step laddering of bowel • Lack of air in colon, rectum

18. Diagnosis: Radiology findings • CT scans • Benefits: high sensitivity and specificity (90%), gives information on intra and extraluminal pathology, highly sensitive for free air/fluid, can identify transition zones, hernias, and bowel ischemia

19. Diagnosis: Radiology findings • Findings: • Dilated bowel • Transition zone from dilated to collapsed • Passage of contrast material (partial) or not (complete) • Bezoars, masses

20. Treatment

21. Treatment • Initial management of all patients should include: • NGT decompression • Judicious fluid resuscitation • Correction of electrolyte imbalances • Foley catheter and close monitoring or UOP • +/- central venous and/or arterial catheters

22. Treatment • Majority of cases (60-82%) can be treated conservatively with non-operative management (NOM) • Three indications for Early Operative Management (EOM):

23. 1: Perforation • Any patient with peritonitis or free air-indicating perforation should go straight to OR

24. Treatment Yes OR

25. 2: Ischemia • Any patients with concerning signs/symptoms for gangrenous or ischemic bowel should also go to the OR ASAP

26. Signs of bowel ischemia • Clinical: sensitivity 40-50% • Hypotension • Tachycardia • Fever or leukocytosis, • Lactic acidosis • SIRS response • Deterioration in exam

27. 1983

28. Clinical symptoms, base deficit, leukocytosis, blood glucose, and SIRS were assessed • →SIRS and base deficit were independently associated with gangrenous bowel • Sensitivity: 92%, Specificity: 96% • PPV: 92%, NPV: 96% 2004

29. Signs of bowel ischemia • Plain films • Bowel wall edema, portal venous gas • CT: sensitivity 85-90% • Thickened bowel wall, target sign, mesenteric stranding, congestion, ascites, pneumatosis, portal venous gas, decreased bowel wall enhancement

30. Treatment

31. 3: High grade, or closed loop SBO • Patients with high grade SBO, or those with closed loop obstruction should be strongly considered for early operative management

32. Signs of high grade SBO > 25mm Air-fluid levels of differential height in the same loop Air fluid width of 25 mm or more

33. Accuracy of plain X-ray to diagnose a high grade SBO • Sensitivity 66-75% • Results of this technique are: • Equivocal in about 20%–30% • Normal, nonspecific, or misleading in 10%–20% Maglinte AJ, AJR Am J Roentgenol 1997

34. Signs of high grade SBO • Sensitivity 80-93% • Contrast does not pass transition zone • Colon with little gas or fluid • Fecalization of small bowel

35. Diagnosis: Radiology findings • EAST Guidelines 2012 • Level 1 recommendation for CT scans in SBO as they can provide incremental increase in information compared to plain films in differentiating grade, severity and etiology that may lead to changes in management

36. Treatment No Closed loop or high grade SBO? Yes-OR

37. Summary: treatment • Three indications for early operative management: • Perforation • Ischemia • Closed loop or high grade obstruction • All others can be considered for NOM

38. Treatment No Closed loop or high grade SBO? Yes-OR No-obs

39. Principles of NOM • Bowel rest, NGT decompression, fluid resuscitation • Serial abdominal exams and blood tests, consider serial abdominal films • Explore if deterioration in clinical exam, or new e/o ischemia or perforation • Keep in mind…

40. NOM • Delay to OR is associated with: • Longer LOS • Increased incidence of bowel necrosis and need for bowel resection • Increased mortality • Increased morbidity

41. NOM • Given risks of delay to surgery: • How long should NOM trial last? • Studies suggest 48hrs although can be longer in pSBO • NIS data suggest delay of ≥4d associated with 64% increase in mortality and increased LOS Schraufnagel et al, J Trauma 2013

42. Are there any decision making aids?

43. NOM • EAST Guidelines 2012 • Level 2 recommendation • Consider water soluble contrast administration for prognosis and/or treatment in patients who fail to improve within 48hrs

44. Water soluble contrast • Hyperosmolar radiopaque agent • Potential aid in prognosis • Passage of contrast into LB may predict successful NOM • Failure of progression predicts need for OR • Theoretically decreases bowel wall edema and may promote resolution of SBO

45. Water-Soluble Contrast (WSCA) – Diagnostic and Therapeuticrole Br J Surg. 2010 Apr;97(4):470-8. • 50–100ml Gastrografin or 40ml Urografin administered orally • Abdominal plain radiographs after 4 h, 8 h or 24 h to follow contrast through the GI-tract

46. Water-Soluble Contrast (WSCA) – Diagnostic and Therapeuticrole Br J Surg. 2010 Apr;97(4):470-8. Meta-analysis of 14 prospective randomized controled studies

47. Water-Soluble Contrast (WSCA) – Diagnostic and Therapeuticrole Br J Surg. 2010 Apr;97(4):470-8. If the contrast reaches the colon within 4–24 h, obstruction will resolve without operation in 99% of patients.

48. Effect of WSCA: Need for surgery

49. Effect of WSCA: Hospital length of stay

50. Water-Soluble Contrast (WSCA) – Diagnostic and Therapeuticrole • Conclusion • Water-soluble contrast was effective in predicting the need for surgery in adhesive SBO (sensitivity 96%, specificity 98%) • In addition, it reduced the need for operation and shortened hospital stay. Br J Surg. 2010 Apr;97(4):470-8.