Bowel surgery

Bowel surgery encompasses all surgical procedures of the small and large intestine. The underlying conditions most commonly requiring bowel surgery are malignancies (especially colorectal cancer) and inflammatory processes (e.g., sigmoid diverticulitis). These surgical procedures may require the creation of an artificial bowel outlet (stoma). Depending on the underlying disease process and the planned surgical procedures, a stoma may be temporary or permanent. A permanent stoma is created following a procedure in which continence could not be preserved, whereas a temporary stoma allows for uninterrupted bowel healing (e.g., following surgery). Intestinal stomas are usually loop stomas, consisting of a proximal and a distal end, while end stomas have one opening which functions as an artificial anus. Major complications of bowel surgery include anastomosis insufficiency, which may lead to abscess formation, peritonitis, and sepsis, and fascial dehiscence, which may lead to organ evisceration and incisional hernias. Common stoma complications include skin irritation and dehydration secondary to high output. Bariatric surgery is an effective treatment for weight loss in patients with obesity and metabolic syndrome. Common complications associated with the procedure include dumping syndrome, strictures, and internal hernias.

Further bowel surgery techniques such as left and right hemicolectomy, transverse colectomy, proctocolectomy, and ileal pouch-anal anastomosis are discussed in the articles on colorectal cancer and ulcerative colitis.

Basic surgical approaches

Bowel surgery can either be performed laparoscopically or as a conventional open procedure. The creation of an artificial bowel outlet or stoma (see below) may be necessary.

Elective surgery

The following factors can help maximize surgical efficacy in planned procedures:

• Time surgery to take place in periods in which possible inflammation is absent or low.
• Optimum treatment of comorbid conditions prior to surgery
• Adequate preoperative measures to prevent abdominal infection (e.g., antibiotic prophylaxis, intestinal cleansing )

Emergency surgery

The acute onset of severe illness requiring emergency surgery typically means that preoperative conditions cannot be optimized (see above). This can considerably increase the risk for intraoperative and postoperative complications.

• Measures to prevent complications: in a two-stage surgical procedure, a temporary stoma is created in a first step to divert stool from diseased portions of the bowel, allowing rest, and is reversed in a second step after healing has occurred.
  • Bowel resection with primary anastomosis (preserving intestinal continuity)
    • Creation of a protective loop stoma
    • Bowel restoration at time of stoma reversal (6–8 weeks following primary anastomosis)
  • Alternative approach: Hartmann procedure
    • Bowel resection and creation of an end stoma with an artificial anus if primary anastomosis is not possible
    • Surgical re-anastomosis with restoration of intestinal continuity (∼ 6 months following initial operation)

Stoma (enterostomy, artificial bowel outlet, artificial anus) ^[1]

• Indication: allows removal of feces from the body
• Procedure
  • The site of the stoma is selected and marked prior to surgery
  • The protruding bowel is secured by a support ring to prevent it from slipping back through the incision.
  • A skin barrier that allows for attaching the collection bag is fitted over and around the stoma.

Loop stoma

• Indications
  • Protective loop stoma: protects distally located parts of the intestine (e.g., inflamed parts, fresh anastomoses)
  • Palliative loop stoma: fecal drainage (e.g., cases of distal bowel obstruction)
• Technique
  • Entire loop of bowel is exteriorized
  • Usually, parts of the ileum are used (ileostoma).
  • Handling: the stoma continually drains bowel contents, requiring continuous use of a stoma bag.
  • A protective loop stoma is reversed a few weeks/months following surgery (after sufficient healing of the anastomosis).

End stoma

• Technique
  • Exteriorization of the proximal end of the bowel. The distal end is sutured or stapled closed and remains as a blind pouch in the abdomen.
  • The bowel is pulled out 1–2 cm and then sutured to the skin.
  • Usually, parts of the colon (colostomy) are used.
• Indications
  • An end stoma is created for incontinent patients (acts as an artificial anus)
  • Hartmann procedure
• Handling ^[2]
  • In colostomy patients, irrigation is an option (controlled evacuation of the bowel to have a period free of output, restoring control)
    • Irrigation involves a lavage of the bowel via the stoma to allow for controlled fecal drainage with subsequent temporary removal of the collection bag and coverage of the stoma with a stoma cap or plug (up to 24–48 hours).
    • This enables the patient to participate in activities (e.g. sports) in which a stoma bag would be inconvenient.
  • In ileostomy, irrigation is pointless, since bowel contents are drained continuously rather than intermittently from the small bowel.
  • Depending on the indications for the initial operation and the underlying condition, re-anastomosis with restoration of intestinal continuity may be possible 3–4 months following surgery.

• General postoperative complications, e.g., postoperative hemorrhage
• Surgical wound-related complications, e.g.:
  • Surgical site infection
  • Wound dehiscence
  • Fascial dehiscence
• Postoperative ileus
• Anastomosis insufficiency (anastomotic leak)
• Bowel obstruction, e.g., due to:
  • Anastomotic stricture
  • Intestinal adhesions
• Fecal incontinence, increased stool frequency
• Ostomy complications, e.g., stoma retraction or prolapse

We list the most important complications. The selection is not exhaustive.

Definition ^[3]

• The separation of a fascial closure following abdominal surgery due to, e.g., increased intraabdominal pressure or wound infection
• Partial fascial dehiscence: partial failure of incision sutures, e.g., deep sutures have failed but superficial skin sutures are intact.
• Complete fascial dehiscence: failure of sutures at all layers of the incision

Risk factors ^[3][4]

• Postoperative intraabdominal infection
• Wound healing disorders
• Poor suturing technique
• Surgical site infection
• Increased intraabdominal pressure, e.g., due to distention or coughing
• Patient-related factors: malnutrition, advanced age, obesity, immunosuppression

Clinical features ^[3]

• Most commonly occurs 6–12 days after surgery ^[3][5]
• Profuse serosanguinous drainage
• Possible “popping” or tearing sensation
• Bulge during Valsalva maneuvers
• Visibly protruding intestine in complete fascial dehiscence
• Clinical features of other complications, e.g., intraabdominal infection

Diagnostics

• Primarily a clinical diagnosis
• Consider imaging if there is diagnostic uncertainty: e.g., CT abdomen and pelvis

Treatment ^[3][6]

• Interim management
  • Cover wound with moist dressing.
  • Use adhesive tapes and abdominal binders to prevent further wound dehiscence.
• Definitive treatment: urgent surgical revision with debridement and reapproximation of the fascial edges

Complications

• Organ evisceration: protrusion of abdominal organs through the outer abdomen
• Intraabdominal sepsis
• Incisional hernia

The risk of mortality in fascial dehiscence after laparotomy is up to 35%. ^[3]

Prevention ^[3][6]

• Preoperative preparation: e.g., nutrition support, smoking cessation
• Good surgical technique
• Avoidance of heavy lifting for 4–6 weeks after laparotomy ^[7]

Definition ^[3]

Anastomosis insufficiency is a complication that occurs after surgical connection of two luminal structures and leads to luminal content leakage.

Risk factors ^[8]

• Emergency surgery
• Prolonged operative time
• Decreased perfusion of the anastomosed bowel segments
• Increased pressure within the anastomosis
• Patient-related factors: e.g., malnutrition

Clinical features ^[3]

• Most leaks manifest 5–7 days following surgery. ^[3][9]
• Postoperative fever, tachycardia, ↓ urinary output
• Abdominal distention, pain, and peritoneal signs
• Tender incision wound, purulent (or feculent) drainage

Signs of gastrointestinal leak include fever, tachycardia, peritonitis, and feculent or purulent drainage. ^[10]

Diagnostics ^[3]

• Laboratory studies: ↑ inflammatory markers
• Imaging: CT abdomen and pelvis with PO and/or rectal contrast
  • Supportive findings include bowel wall thickening, fat stranding, free intraperitoneal air, and/or free fluid > 300 mL.
  • Contrast extravasation is often not visualizable.
• Microbiological studies
  • Wound and/or skin cultures
  • Interventional drainage and culture of drainage leak

Treatment ^[3]

Obtain a surgical consult, as treatment depends on the patient's clinical condition and may include:

• Complete bowel rest
• Surgical drainage or diversion
• Broad-spectrum antibiotics for patients with signs of sepsis
• Treatment of complications: e.g., abscess formation, peritonitis

Risk factors ^[11]

• Patient-related
  • Age > 65 years
  • BMI > 25
  • Female sex
  • Diabetes mellitus
  • Abdominal malignancy
• Surgery-related
  • Emergency surgery ^[12]
  • Lack of preoperative stoma marking

Early complications ^[12][13][14]

• Skin irritation: most common
  • Clinical features: range from dermatitis to ulceration
  • Management: Inspect ostomy bag fit and consult an ostomy specialist if skin appears wet and inflamed.
  • Prevention: Dry skin before applying a new bag and consider using skin barriers.
• High-output stoma: daily output > 1500 mL
  • Clinical features: watery stool in ostomy appliance, signs of dehydration
  • Management
    • IV fluid resuscitation and electrolyte repletion
    • AKI workup
    • Input/output monitoring
    • Consult surgery before administering antidiarrheal medications.
  • Complications: AKI, electrolyte imbalance
• Stoma necrosis: usually occurs 24 hours postoperatively
  • Clinical features: discoloration of stoma and pain around the site
  • Management: urgent surgical consult for stoma revision

Late complications ^[12][14][15]

• Stoma retraction
  • The stoma sinks below skin level, leading to poor stoma fit and skin irritation.
  • Management: stomal plate, stomal revision ^[16]
• Stoma prolapse
  • Bowel protrudes through the stomal opening.
  • Management: usually conservative, unless there is concern for bowel ischemia
• Parastomal hernia: risk of incarcerated hernia with mechanical bowel obstruction (MBO)
• Stomal stenosis
  • Narrowing of the stoma causing noisy flatus
  • Management: urgent general surgery consult if there are signs of MBO, e.g., no ostomy output
• Urostomy-related complications
  • Similar to bowel stomal complications
  • Complications may also be related to the bowel segment used for urine diversion.

Indications ^[17]

• BMI ≥ 35 kg/m²
• BMI ≥ 30 kg/m² and type 2 diabetes mellitus
• BMI 30–34.9 kg/m² if non-surgical treatment for obesity and obesity-related comorbidities has been ineffective

Procedures ^[18][19][20]

• Restrictive procedures ^[21]
  • Goal: Reduce stomach volume and limit oral intake.
  • Examples: sleeve gastrectomy (most common form of bariatric surgery), adjustable gastric banding
• Malabsorptive procedures ^[19][21]
  • Goal: bypass portions of the small intestine, thereby impairing absorption of macronutrients
  • Example: Roux-en-Y gastric bypass

Bariatric surgery is an effective treatment for obesity and metabolic syndrome; however, clinicians must weigh these benefits against the risks associated with surgery.

Complications ^[10][22]

• General complications of bowel surgery, e.g.:
  • Anastomotic leaks
  • Strictures
  • Internal hernias
• Procedure-specific complications, e.g.:
  • Esophagitis and acid reflux in sleeve gastrectomy
  • Marginal ulceration, gastrogastric fistula, dumping syndrome, and choledocholithiasis in Roux-en-Y bypass
  • Esophageal or gastric perforation and band slippage in gastric banding
• Acute management
  • ABCDE survey, NPO, emergency preoperative diagnostics, surgical consult
  • Imaging: CXR and abdominal x-ray and/or CT abdomen and pelvis with IV and oral contrast
  • Further measures depend on the underlying condition, e.g., broad-spectrum antibiotics if a leak is suspected.

Do not attempt nasogastric tube insertion without consulting the surgical team because altered anatomy increases the risk of injury from a blind insertion.

Consider nongastrointestinal etiologies for abdominal pain, such as myocardial infarction, because bariatric patients may have additional comorbidities such as coronary artery disease. ^[23]