Large Bowel Obstruction Flashcards
MC Cause of Large Bowel Obstruction
- Colorectal carcinoma is the most common etiology
- Diverticular disease is the second most common > Chronic inflammation in the sigmoid can cause a stricture
complicated diverticulitis with significant inflammation > inflammatory stricture, phlegmon, or abscess.
- The third most common cause of large bowel obstruction is volvulus,
involves the mesentery > High risk of strangulation and ischemia - Functional causes of large bowel obstruction are less common > colonic pseudo-obstruction (Ogilvie’s syndrome), narcotic-induced adynamic ileus, and adynamic ileus due to systemic illness such as toxic megacolon from Clostridium difficile infection.
How many cm of Cecum is concerning
Cecal distension of 9 to 12 cm on plain abdominal film is concerning for impending perforation.
MC Procedures associated with Colonic Pseudo obstruction
Recent orthopedic or gynecologic procedures
What causes air-fluid levels of the small bowel with distension.
- Incompetent ileocecal valve > reflux of contents back into the small intestine may reflect as air-fluid levels of the small bowel with distension.
the classic findings of Volvolus on plain films
- Sigmoid volvulus > “bent inner tube” sign or
“omega loop.” - Cecal volvulus > “coffee bean”
Other classic findings of volvulus and obstructing cancer with Contrast Enema
“bird’s beak” deformity at the site of a volvulus
“apple core lesion” at the site of an obstructing cancer.
Contrast Enema Result in Pseudo obstruction and fecal impaction
- Colonic pseudo-obstruction > contrast will freely flow without evidence of transition point.
- fecal impaction > contrast may be therapeutic.
Who requires emergent intervention.
- Patients who present with impending perforation on imaging
- pneumoperitoneum (evidence of existing perforation),
- peritonitis
- clinical signs of sepsis
The Goal of Surgery
Decompress the Bowel
Stoma or No stoma ?
- under emergent setting where the patient is unstable or with gross intraabdominal contamination
> primary anastomosis is contraindicated
Segmental resection with an end stoma is the safest choice.
Rt Side vs Lt Side Lesions
Rt Side, proximal to the splenic flexure
> right hemicolectomy with end ileostomy
Lt Side lesions >
Hartmann procedure should be performed.
When is subtotal colectomy is indicated
- perforation
- large serosal injuries
- or synchronous lesions are found at the time of exploration.
- When performing a subtotal colectomy in the emergent setting, creation of an end ileostomy is often necessary.
when to Consider Diverting loop colostomy ?
- unresectable malignancy
- diffuse carcinomatosis
- severe inflammation
- patients who are extremely unstable
> a diverting loop colostomy proximal to the obstruction is indicated
Loop Vs End Colostomy
- A loop colostomy is preferred over an end colostomy as the blind end that is left in the abdomen may perforate.
- A colostomy relieves patients of their symptoms and limits subsequent concerns for an anastomotic leak.
colostomies associated Morbidity
- high rates of parastomal hernia (50%)
- decreased quality of life
- and low rates of stoma closure.
Non emergent Setting for Rt side Lesion
In the absence of generalized peritonitis, perforation, or sepsis
- Rt side obstruction and the point of obstruction is proximal to the splenic flexure >
right hemicolectomy with primary anastomosis
low anastomotic leak rates (< 5%)
Alternative ?
- Right hemicolectomy with primary anastomosis and proximal diverting loop ileostomy.
- Considered in patients with high Concern for leak and may delay chemo later
> Small bowel dilation
> immunosuppressed
> on steroids
> or malnourished from chronic obstruction
Additionally, reversal of a loop ileostomy is a less morbid surgery than reversal of an end ileostomy.
Obstructing lesion arising in the descending sigmoid colon, rectum, or anus
- Traditionally, primary anastomosis at the initial procedure was avoided because of the higher rates of anastomotic leak (20%).
- Currently, segmental resection with primary anastomosis is a good option for carefully selected patients if the proximal colon is not dilated significantly.
High Risk patient with Left side Obstruction
- Segmental colectomy, anastomosis, and a diverting loop ileostomy.
- This still allows for diversion of the fecal stream
> in the event of an anastomotic leak
intraabdominal sepsis is contained and can usually be managed nonoperatively with percutaneous drainage and antibiotics
Loop ileostomy vs Hartmann’s
- Loop ileostomy reversal is a less invasive operation and patients will more likely undergo this procedure to have their intestinal continuity restored as compared to reversing a Hartmann’s procedure.
Colonic Lavage
- Colonic lavage may permit a single-stage surgery in the setting of a left-sided large bowel obstruction.
- Following the resection
- colon fully mobilized at both hepatic and splenic flexures
- Allow descending colon to extend beyond the abdominal cavity
- Appendectomy is performed, and a catheter is passed into the cecum and secured with a purse-string suture.
- Catheter is attached to a large bag of warmed saline
- If the cecum is thinned, insert the catheter into the terminal ileum
-The staple line at the distal segment of colon is opened and a generous length of sterile corrugated tubing is placed into the lumen of the descending colon. - 3-6 Liters of warmed saline is then flushed through the colon.
- This is continued until the effluent clears
