Waldeyer fascia (rectosacral fascia)

What artery is contained within the lateral rectal stalks?

The middle rectal artery

What muscles make up the pelvic floor (pelvic diaphragm)?

Pubococcygeus, iliococcygeus, puborectalis (which form the levator ani)

Where does the pelvic floor (pelvic diaphragm) lie?

Between the pubis, obturator fascia, sacrum, and ischial spines

What artery runs close to the bowel in the mesentery as part of a vascular arcade that connects the superior mesenteric artery and inferior mesenteric artery?

The marginal artery of Drummond

What artery found low in the mesentery, near the root, is part of a vascular arcade that connects the proximal middle colic artery to the proximal inferior mesenteric artery?

The arc of Riolan (meandering mesenteric artery)

What is the most proximal branch of the inferior mesenteric artery?

Left colic artery

Describe the venous drainage of the colon and rectum?

Right and proximal transverse colon drain into the superior mesenteric vein, which joins with the splenic vein to become the portal vein

Distal transverse colon, descending colon, sigmoid, and most of the rectum drain into the inferior mesenteric vein, which drains into the splenic vein that joins with the superior mesenteric vein to become the portal vein

Anal canal drains by way of the middle and inferior rectal veins into the internal iliac veins, which drain into the inferior vena cava

What nodal chain do lymphatics from the colon and proximal two-thirds of the rectum drain into?

Para-aortic nodal chain

What nodal chains do lymphatics from the distal rectum and anal canal drain into?

Para-aortic nodal chain or superficial inguinal nodal chain

What kind of neurologic injury after rectal surgery generally results in sympathetic dysfunction characterized by retrograde ejaculation and bladder dysfunction?

Severing of the hypogastric nerves near the sacral promontory

What kind of neurologic injury after rectal surgery generally results in impotence and atonic bladder?

Injury to the mixed parasympathetic and sympathetic periprostatic plexus

What is the most prevalent species of bacteria in the colon?

Bacteroides species

What is the most common aerobe in the colon?

Escherichia coli

In what colonic segment are bacteria the most metabolically active?

The cecum

>3 loose stools/d

How is constipation defined?

<3 stools/wk

What are absolute contraindications to bowel preparation?

Complete bowel obstruction, free perforation

DIVERTICULITIS

How are the diverticula with colonic diverticulosis formed?

Mucosa herniates through the colon at sites of penetration of the muscular wall by arterioles on the side of the antimesenteric taeniae

What area of the colon is most commonly affected by diverticula?

Sigmoid colon (80%)

What segment of the colon has the smallest intraluminal diameter?

Sigmoid colon

What is the treatment for uncomplicated diverticulitis?

Antibiotics on an outpatient basis; if patient has significant pain (localized peritonitis), admit to the hospital and give intravenous (IV) antibiotics for ~48 hours

How should patients be followed after an episode of uncomplicated diverticulitis?

After symptoms have subsided for at least 3 weeks, a colonoscopic examination should be performed to establish the presence/location of the diverticula and to exclude cancer (mimic diverticulitis)

What is the approximate chance of a patient who recovered from an initial episode of uncomplicated diverticulitis developing a second attack of diverticulitis?

<25%

What is the estimated percentage of patients who recovered from an initial episode of uncomplicated diverticulitis requiring a subsequent emergency colectomy or colostomy?

~5%

Although controversial, what types of patients might you offer an elective sigmoid colectomy?

Young patients with an episode of diverticulitis (<45 years old), patients with 2 episodes of diverticulitis, and immunocompromised patients

What is the treatment for an abscess complicating diverticulitis?

The preferred treatment is computed tomography (CT) or ultrasound-guided percutaneous drainage or drainage of a pelvic abscess into the rectum through a transanal approach followed by elective surgery ~6 weeks after drainage of the abscess when the patient has completely recovered from the infection versus a more undesirable transabdominal approach by laparotomy

What are the 2 causes of generalized peritonitis resulting from diverticulitis?

A perforated diverticulum into the peritoneal cavity that is not sealed by the body’s normal defenses; an initially localized abscess that expands and suddenly bursts into the peritoneal cavity

A Hartmann procedure: resection of the diseased sigmoid colon; creation of a descending colostomy using noninflamed tissue; closure of the divided end of the rectum with suture/staples

What is the usual time period to wait before restoring intestinal continuity by reversing a Hartmann procedure for perforated diverticulitis?

At least 10 weeks (when patient has completely recovered from their illness)

What is the Hinchey classification grading system for diverticulitis?

Stage I Diverticulitis with associated pericolic abscess

Stage II Diverticulitis associated with distant abscess (retroperitoneal or pelvic)

Stage III Diverticulitis associated with purulent peritonitis

Stage IV Diverticulitis associated with fecal peritonitis

VOLVULUS

What is the most common colonic segment to be involved in a volvulus?

Sigmoid colon

What is the least common colonic segment to be involved in a volvulus?

Transverse colon

What is a cecal bascule?

The cecum folds anteromedial to the ascending colon from the presence of a constricting band across the ascending colon

What findings might you see on plain film, CT scan, and barium enema with a sigmoid volvulus?

Plain film: bent inner tube with apex in the right upper quadrant

CT scan: mesenteric whorl

Barium enema: bird’s beak deformity

What is the treatment for sigmoid volvulus?

Appropriate resuscitation; decompression with placement of a soft rectal tube through the proctoscope past the twist of the volvulus and leaving the rectal tube in place

If a rectal tube cannot be passed, detorsion of the volvulus with a colonoscope

If unable to detorse volvulus by rectal tube or colonoscopy, perform Hartmann operation procedure

Confirm the reduction with an abdominal radiograph, attempt a full colonoscopic examination after cleansing the bowel with cathartics, perform an elective sigmoid colon resection

What is the recurrence rate for sigmoid volvulus without surgical intervention?

~50%

What is a cecal (cecocolic) volvulus?

An axial rotation of the terminal ileum, cecum, and ascending colon with concomitant twisting of the associated mesentery from a lack of fixation of the cecum to the retroperitoneum

A gas-filled comma shape with the concavity facing inferiorly and to the right (upside down comma sign), a circular shape with a narrow, triangular density pointing to the right and superiorly, a dilated cecum displaced to the left side of the abdomen

What is the treatment for a cecal volvulus?

The procedure of choice is a right colectomy with primary anastomosis; if frankly gangrenous bowel, resect right colon and create an ileostomy; cecopexy is another option (higher recurrence rates)

OBSTRUCTION

What is the most common cause of large intestinal obstruction in the United States?

Colorectal cancer

What is the most common cause of large intestinal obstruction in Russia, Eastern Europe, and Africa?

Colonic volvulus (high-fiber diets)

What is a closed loop obstruction?

An obstruction featuring the occlusion of the proximal and distal parts of the bowel