Bowel Obstruction

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Information about Bowel Obstruction

Published on January 17, 2009

Author: andreamd1963

Source: slideshare.net

Small Bowel Obstruction Liane S. Feldman, MD, FRCSC October 25, 2000

Small Bowel Obstruction One of the most common problems we face Partial or complete blockage of lumen Our Goal = intervene before gangrenous bowel develops

One of the most common problems we face

Partial or complete blockage of lumen

Our Goal = intervene before gangrenous bowel develops

Classification of SBO Paralytic (ileus) Mechanical Partial Complete SBO

Causes of Mechanical SBO Extrinsic Intrinsic Intraluminal Intramural

Extrinsic

Intrinsic

Intraluminal

Intramural

SBO: Extrinsic Causes Adhesions postop, congenital, postinflammatory Hernias external, internal Volvulus Mass effect abscess, carcinomatosis, endometriosis, pseudocyst

Adhesions

postop, congenital, postinflammatory

Hernias

external, internal

Volvulus

Mass effect

abscess, carcinomatosis, endometriosis, pseudocyst

SBO: Intraluminal Causes Gallstone Intussusception Polypoid lesion Bezoar Enteroliths Foreign body Meconium ileus Parasites Inspissated feces Inspissated barium

Gallstone

Intussusception

Polypoid lesion

Bezoar

Enteroliths

Foreign body

Meconium ileus

Parasites

Inspissated feces

Inspissated barium

SBO: Intramural Causes Congenital atresia, stricture, web, duplication, Meckels Inflammatory Crohn’s, radiation, diverticulitis, postischemic stricture, meds (NSAID, KCl) Neoplasm primary, secondary Traumatic

Congenital

atresia, stricture, web, duplication, Meckels

Inflammatory

Crohn’s, radiation, diverticulitis, postischemic stricture, meds (NSAID, KCl)

Neoplasm

primary, secondary

Traumatic

Etiology of SBO Adhesions……..60% Malignancy…….20% Hernia…………….10% IBD………………….5% Volvulus…………..3% Miscellaneous…2%

Adhesions……..60%

Malignancy…….20%

Hernia…………….10%

IBD………………….5%

Volvulus…………..3%

Miscellaneous…2%

Approach to SBO How can we recognize SBO? Is it partial or complete? Is it simple or strangulated?

How can we recognize SBO?

Is it partial or complete?

Is it simple or strangulated?

Recognition of SBO: History Previous surgery, esp. pelvic Abdominal pain Colicky early on Vomiting: the more distal, the later the onset Obstipation

Previous surgery, esp. pelvic

Abdominal pain

Colicky early on

Vomiting: the more distal, the later the onset

Obstipation

Recognition of SBO: Exam Distention: Varies with level Bowel sounds: may be hypoactive if late R/o incarcerated groin, femoral, obturator (on rectal) hernia !!! Rectal exam: masses, blood

Distention: Varies with level

Bowel sounds: may be hypoactive if late

R/o incarcerated groin, femoral, obturator (on rectal) hernia !!!

Rectal exam: masses, blood

Radiology: plain films Supine and upright Distended loops of SB, air-fluid levels, paucity of colonic air But diagnostic only 50-80% of the time Remember gasless abdomen with closed loop obstruction (air can’t accumulate in loop)

Supine and upright

Distended loops of SB, air-fluid levels, paucity of colonic air

But diagnostic only 50-80% of the time

Remember gasless abdomen with closed loop obstruction (air can’t accumulate in loop)

Radiology: CT Scan Discriminates mechanical vs ileus Fluid or air-filled loops proximally Transition zone Collapsed bowel distally Can look for extrinsic causes Note that obstructing ileocecal lesion can look like ileus

Discriminates mechanical vs ileus

Fluid or air-filled loops proximally

Transition zone

Collapsed bowel distally

Can look for extrinsic causes

Note that obstructing ileocecal lesion can look like ileus

New modalities Ultrasound SB loop dilated > 3 cm Dilated loop > 10 cm Peristalsis of dilated loop Collapsed colon MRI

Ultrasound

SB loop dilated > 3 cm

Dilated loop > 10 cm

Peristalsis of dilated loop

Collapsed colon

MRI

Partial or Complete Obstruction? Can be diagnostic challenge Important because risk of strangulation and thus initial management differs Partial: negligible risk of strangulation (except Richter’s), so nonoperative first Complete: 20-40% risk of strangulation, so early operation required

Can be diagnostic challenge

Important because risk of strangulation and thus initial management differs

Partial: negligible risk of strangulation (except Richter’s), so nonoperative first

Complete: 20-40% risk of strangulation, so early operation required

Partial or Complete Obstruction? Partial suggested by: Flatus 6-12 hrs after onset Colonic air 6-12 hrs after onset Patients with complete obstruction may still pass gas early on due to distal peristalsis

Partial suggested by:

Flatus 6-12 hrs after onset

Colonic air 6-12 hrs after onset

Patients with complete obstruction may still pass gas early on due to distal peristalsis

Partial or Complete Obstruction? Barium test: 50 ml of barium via NG Clamp tube x 1 hour (unclamp if vomits, etc) Repeat x-rays over next 12-24 hrs See if get to colon Contraindicated if suspect LBO: inspissates CT scan can also be useful Degree of distention, amount of distal air

Barium test: 50 ml of barium via NG

Clamp tube x 1 hour (unclamp if vomits, etc)

Repeat x-rays over next 12-24 hrs

See if get to colon

Contraindicated if suspect LBO: inspissates

CT scan can also be useful

Degree of distention, amount of distal air

Simple vs Strangulated SBO Presence of strangulation increases mortality to 20% and morbidity to 40% So why not just operate on the ones with strangulation? Problem: we can’t diagnose strangulation on clinical grounds!!!

Presence of strangulation increases mortality to 20% and morbidity to 40%

So why not just operate on the ones with strangulation?

Problem: we can’t diagnose strangulation on clinical grounds!!!

“ Classic” signs of strangulation? ...Continuous pain ...Fever ...Tachycardia ...Peritoneal signs ...Leukocytosis ...Elevated K, amylase, alk phos, LDH, CK PREDICT NECROSIS, NOT ISCHEMIA

...Continuous pain

...Fever

...Tachycardia

...Peritoneal signs

...Leukocytosis

...Elevated K, amylase, alk phos, LDH, CK

PREDICT NECROSIS, NOT ISCHEMIA

Predicting Reversible Ischemia Unfortunately, reversible ischemia is not discernable clinically CT: thickened bowel wall, pneumatosis, PV air, bowel wall nonenhancement Most are signs of necrosis not ischemia

Unfortunately, reversible ischemia is not discernable clinically

CT: thickened bowel wall, pneumatosis, PV air, bowel wall nonenhancement

Most are signs of necrosis not ischemia

Management Resuscitation Tube decompression Timing of surgery Operative strategy Specific examples

Resuscitation

Tube decompression

Timing of surgery

Operative strategy

Specific examples

Resuscitation All patients have intravascular depletion: Decreased po intake Vomiting Fluid sequestration Aggressive resuscitation with IV isotonic solution required Urine output, pulse guide resuscitation CVP line in some cases

All patients have intravascular depletion:

Decreased po intake

Vomiting

Fluid sequestration

Aggressive resuscitation with IV isotonic solution required

Urine output, pulse guide resuscitation

CVP line in some cases

Tube decompression NG tube: removes swallowed air and gastric fluid Symptomatic relief: vomiting, pain Can give barium down tube Prevent aspiration during induction Longer tubes not better than NG tubes

NG tube: removes swallowed air and gastric fluid

Symptomatic relief: vomiting, pain

Can give barium down tube

Prevent aspiration during induction

Longer tubes not better than NG tubes

Timing of surgery: Partial SBO Usually patients suspected of adhesions from previous surgery Initial nonoperative treatment for few days 60-85% will resolve without operation Repeat physical exam and AXR q12 hours Reassess decision to operate or not q12 hours Worsening status or failure to improve are indications for OR

Usually patients suspected of adhesions from previous surgery

Initial nonoperative treatment for few days

60-85% will resolve without operation

Repeat physical exam and AXR q12 hours

Reassess decision to operate or not q12 hours

Worsening status or failure to improve are indications for OR

Timing of surgery: Complete SBO The issue 20-40% incidence of strangulation Cannot predict reversible ischemia clinically The Strategy Operation after initial 12 - 24 hours of resuscitation

The issue

20-40% incidence of strangulation

Cannot predict reversible ischemia clinically

The Strategy

Operation after initial 12 - 24 hours of resuscitation

Operative Strategy May involve: Lysis of adhesions Resection of obstructing lesion with anastomosis Intestinal bypass Rarely, stoma placement

May involve:

Lysis of adhesions

Resection of obstructing lesion with anastomosis

Intestinal bypass

Rarely, stoma placement

Operative Technique 1. Clear adhesions to anterior abdominal wall Avoid blind finger dissection and excessive countertraction; careful, sharp dissection best 2. Inspect region of cecum If distended, is this really a LBO? 3. Work back from collapsed bowel to point of obstruction Don’t need to free adhesions proximal to point of obstruction

1. Clear adhesions to anterior abdominal wall

Avoid blind finger dissection and excessive countertraction; careful, sharp dissection best

2. Inspect region of cecum

If distended, is this really a LBO?

3. Work back from collapsed bowel to point of obstruction

Don’t need to free adhesions proximal to point of obstruction

Assessing viability of intestine Place back in abdomen with warm towel Conventional clinical criteria: normal color, peristalsis, marginal arterial pulsations Doppler probe does not improve this impression IV fluorescein dye (1 amp) with Wood lamp more reliable than clinical judgement alone for borderline bowel (Bulkley, Ann Surg , 1981) Rarely, second look in 24 hours

Place back in abdomen with warm towel

Conventional clinical criteria: normal color, peristalsis, marginal arterial pulsations

Doppler probe does not improve this impression

IV fluorescein dye (1 amp) with Wood lamp more reliable than clinical judgement alone for borderline bowel (Bulkley, Ann Surg , 1981)

Rarely, second look in 24 hours

Adhesions Pathophysiology Transudated fibrinogen activated by tissue factor Forms fibrin clot which initiates adhesion formation Peritoneal trauma and ischemia promote adhesion formation by release of tissue factor

Pathophysiology

Transudated fibrinogen activated by tissue factor

Forms fibrin clot which initiates adhesion formation

Peritoneal trauma and ischemia promote adhesion formation by release of tissue factor

Prevention of Adhesions Avoid serosal trauma Avoid lysis of nonobstructing adhesions Avoid spillage in peritoneal cavity Aggressive irrigation of debris Adjuvent agent: bioresorbable membrane of hyaluronic acid and carboxymethylcellulose Reduced adhesions to anterior abdominal wall in RCT (Becker, JACS , 1996)

Avoid serosal trauma

Avoid lysis of nonobstructing adhesions

Avoid spillage in peritoneal cavity

Aggressive irrigation of debris

Adjuvent agent: bioresorbable membrane of hyaluronic acid and carboxymethylcellulose

Reduced adhesions to anterior abdominal wall in RCT (Becker, JACS , 1996)

Incarcerated hernia Acutely incarcerated nonreducible hernia = early operative management Site of incarceration is external ring - make sure bowel does not reduce prior to direct examination If suspect strangulation, consider midline incision

Acutely incarcerated nonreducible hernia = early operative management

Site of incarceration is external ring - make sure bowel does not reduce prior to direct examination

If suspect strangulation, consider midline incision

Intraabdominal abscess Severe localized ileus near abscess mimics SBO Drainage of abscess often sufficient to relieve SBO May be amenable to CT-guided drainage

Severe localized ileus near abscess mimics SBO

Drainage of abscess often sufficient to relieve SBO

May be amenable to CT-guided drainage

Malignant tumor Primary or secondary neoplasm with SBO - in general, treat like any other obstruction History of cancer or suspected carcinomatosis- may be challenge Don’t assume the worst: up to 40% due to benign causes (adhesions, radiation, stricture) Individualize treatment

Primary or secondary neoplasm with SBO - in general, treat like any other obstruction

History of cancer or suspected carcinomatosis- may be challenge

Don’t assume the worst: up to 40% due to benign causes (adhesions, radiation, stricture)

Individualize treatment

Radiation enteritis Acute enteritis (within few wks of radiation): Try tube decompression, steroids Chronic Laparotomy usually required Bowel looks fibrotic, gray-white, thick adhesions Local resection or bypass if resection difficult To ascending colon - outside of pelvic radiation field Avoid anastomosis of radiated bowel

Acute enteritis (within few wks of radiation):

Try tube decompression, steroids

Chronic

Laparotomy usually required

Bowel looks fibrotic, gray-white, thick adhesions

Local resection or bypass if resection difficult

To ascending colon - outside of pelvic radiation field

Avoid anastomosis of radiated bowel

Acute postoperative obstruction Risk of obstruction 1% within 4 weeks Causes: adhesions (90%); internal hernia, abscess, volvulus, intussusception (10%) Challenge is to differentiate ileus and SBO CT with oral contrast very useful R/o abscess Delineate degree, site of obstruction

Risk of obstruction 1% within 4 weeks

Causes: adhesions (90%); internal hernia, abscess, volvulus, intussusception (10%)

Challenge is to differentiate ileus and SBO

CT with oral contrast very useful

R/o abscess

Delineate degree, site of obstruction

Acute postoperative obstruction Management: like late obstructions Partial: initially nonoperative, NG decompression Complete: early surgery Laparotomy required in up to 50% As interval from first operation approaches 2-3 weeks, character of adhesions worsens and operation is much harder

Management: like late obstructions

Partial: initially nonoperative, NG decompression

Complete: early surgery

Laparotomy required in up to 50%

As interval from first operation approaches 2-3 weeks, character of adhesions worsens and operation is much harder

Recurrent Obstruction Risk of SBO after surgery is about 5% Recurrence rates vary from 5-30% Initial nonoperative trial usually safe Bowel less mobile and apt to twist due to dense adhesions Evaluate each patient to formulate plan Bowel fixation procedures largely abandoned

Risk of SBO after surgery is about 5%

Recurrence rates vary from 5-30%

Initial nonoperative trial usually safe

Bowel less mobile and apt to twist due to dense adhesions

Evaluate each patient to formulate plan

Bowel fixation procedures largely abandoned

Role of laparoscopy in SBO Key is careful selection: (1) mild distention (2) proximal obstruction (3) partial obstruction (4) “single band” anticipated Best chance of cure: recurrent abdominal pain in localized area with adhesions at same site

Key is careful selection:

(1) mild distention

(2) proximal obstruction

(3) partial obstruction

(4) “single band” anticipated

Best chance of cure: recurrent abdominal pain in localized area with adhesions at same site

Take Home Messages How to diagnose SBO History, physical, radiology Classify it as partial or complete Operate early in complete SBO (12-24 hrs) because we cannot diagnose strangulation clinically

How to diagnose SBO

History, physical, radiology

Classify it as partial or complete

Operate early in complete SBO (12-24 hrs) because we cannot diagnose strangulation clinically

Proximal or Distal?

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