Colon and Small Bowel—Large Bowel Obstruction
Concept
Broad DDx but likely malignancy in older population.
History can be helpful here. You will probably be pushed into an operation on someone with obstruction second- ary to malignancy or diverticulitis related stricture or perhaps a patient that has even perforated secondary to their obstruction.
Way Question May be Asked?
“61 y/o male evaluated in emergency room with recent constipation and change in bowel habits, complaining of sudden onset of diffuse abdominal pain/distension and has free air on AXR. What would you do?” Be prepared to see an x-ray here.
How to Answer?
Have a DDx in Your Mind and Work Through
Obstructing cancer
Diverticular/ischemic stricture Volvulus
Pseudo-obstruction (Ogilvie’s)
Don’t forget about hx of prior operations
Physical Exam
Examine abdomen
Rectal exam, heme occult test
Rigid sigmoidoscopy (unless true peritoneal signs, will have therapeutic value if volvulus)
Surgical Treatment
If no signs of peritonitis:
Gastrografin enema CT scan abdomen
NGT/Foley/IVF/NPO/Serial exams
Try to convert to near-obstructing lesion and perform semi-electively after bowel prep
If signs of peritonitis or complete obstruction:
OR after initial evaluation and resuscitation (lines, IVF, Abx)
In OR:
(1) Right hemicolectomy for obstructing lesions of right and proximal transverse colon (can do primary anastomosis here)
(2) Left hemicolectomy/sigmoidectomy with colostomy and mucus fistula/Hartman’s pouch for lesions obstructing distal transverse colon/left colon/or sigmoid
(3) Subtotal colectomy with primary anastomosis for obstructing lesion in left/sigmoid with perfo- ration of cecum, useful in pts with metachron- cous lesions found after previous resection for pts with synchronous cancers. Not good option in unstable pt given time involved
(4) Right hemicolectomy/ileostomy/mucus fistula for unstable pt with obstructing sigmoid/rectal lesion with perforation of cecum and gross con- tamination! Pt will then need work-up for malig- nancy and second operation to remove disease if survives (careful how close together you put stomas unless you want a situation where the appliance will never seal properly!)
(5) Defunctioning stoma (transverse loop colostomy) and then a later operation to remove obstructing tumor/mass in descending colon/sigmoid
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Common Curveballs
Signs of peritonitis
Perforation of right colon with mass on left
Rigid sigmoidoscopy won’t find cause for obstruction Pt will be unstable intra-op
Pt will have AAA
Pt will develop post-op abscess or abdominal compartment syndrome
Pt will develop ischemia at colostomy site Pt will become coagulopathic during operation
Inability to pass rectal tube for volvulus or keep in place to give pt bowel prep
Cecum will get over-distended in follow-up of pseudo- obstruction or will perforate
Distal cancer will be fixed to pelvic structures
Ureter/duodenal/liver injury while mobilizing right colon Splenic injury will mobilizing splenic flexure
Hard peripheral liver lesion identified at time of emergency operation for peritonitis
Pt will have had prior abdominal/colonic surgery Entering into a discussion of various stoma complica-
tions (stenosis, hernia, retraction, prolapse)
Strikeouts
Doing anastomosis in face of frank contamination Not knowing how to contruct ileostomy/mucus
fistula/Hartman pouch
Talking about on-table bowel lavage
Performing long operation in elderly/unstable pt Using Barium enema rather than water soluble contrast
when concerned about cause of obstruction and pos- sible perforation
Discussing colonoscopically placed stents for malignant obstruction (an option, but risk of perforation high and don’t mention unless really familiar with this modality)
Waiting for CT scan on pt with peritonitis Discussing cecostomy tubes or IV neostigmine
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