9. Forms of Surgical Deviations of the Intestinal System: Stomas

I. Surgical Deviation of Intestinal Flow

Surgical deviation: Operative alteration of the normal passage of intestinal content
Goal → Divert feces/gas, bypass obstruction, protect anastomosis, allow healing, palliate symptoms, or provide nutrition
Main forms → Stoma and bypass
Can be temporary or permanent

Stoma

Stoma: Surgically created opening between intestine and skin surface, usually on abdominal wall
Allows external diversion of feces/gas or delivery of enteral nutrition
Output depends on bowel segment → Ileostomy liquid, colostomy more formed, jejunostomy usually feeding access
Can be planned/elective or emergency

Bypass

Bypass: Rerouting intestinal contents around a diseased/obstructed segment without bringing bowel to skin
Creates internal diversion/anastomosis
Indications → Obstructed or strictured bowel, palliative GI cancer, congenital anomaly, selected Crohn strictures, bariatric surgery
Examples → Gastrojejunostomy for gastric outlet obstruction, ileotransverse bypass, biliodigestive bypass, gastric bypass for morbid obesity

II. Main Types of Stomas

Classification by Bowel Segment

Type	Definition / site	Output and practical point
Colostomy	Colon opened to abdominal wall	More formed stool, less fluid/electrolyte loss than ileostomy Common site → Sigmoid colostomy in left lower quadrant
Ileostomy	Ileum opened to abdominal wall	Liquid/semi-liquid output, digestive enzymes irritate skin Risk → Dehydration, Na/K/Mg loss, renal injury
Jejunostomy	Jejunum opened to abdominal wall	Usually feeding jejunostomy; not mainly fecal diversion High-output fistula/stoma risk if used for diversion
Urostomy	Urinary diversion, often ileal conduit	Urine diverted to skin after cystectomy or urinary tract disease; not intestinal fecal stoma but often examined together

Classification by Construction

1. End Stoma

Divided proximal bowel end is brought out and matured to skin
Distal bowel may be removed, closed as a rectal stump, or brought out as mucus fistula
Can be permanent or temporary

End colostomy → Hartmann procedure, abdominoperineal resection, obstructing left colon/rectal cancer
End ileostomy → Total proctocolectomy, severe IBD, FAP, bowel necrosis/perforation

2. Loop Stoma / Double-Lumen Stoma

Loop of bowel is brought through abdominal wall and opened
Both proximal and distal lumens are visible in one stoma
Usually temporary
Purpose → Divert fecal stream while distal bowel/anastomosis heals

Loop ileostomy → Common protective stoma after low anterior resection/coloanal anastomosis
Loop colostomy → Temporary decompression/diversion, often transverse or sigmoid
Distal limb may pass mucus

3. Double-Barrel Stoma

Both divided bowel ends are brought separately to the skin surface
Proximal stoma → Functional fecal diversion
Distal stoma → Mucus fistula
Often used when later re-anastomosis is planned but primary anastomosis is unsafe

Indications → Trauma, ischemia, perforation, severe contamination, emergency resection

Classification by Duration

Temporary stoma → Reversal planned after healing/recovery or after oncological treatment
Permanent stoma → Reversal not possible or not appropriate

Temporary examples → Protective loop ileostomy, Hartmann colostomy planned for reversal, diversion for trauma/perforation
Permanent examples → End colostomy after abdominoperineal resection, severe anal sphincter destruction/incontinence, incurable anorectal malignancy

III. Main Indications for Stoma Creation

1. Temporary Fecal Diversion

Protect distal anastomosis → Especially low colorectal/coloanal anastomosis
Allow healing of distal bowel/rectum/perineal wound
Reduce consequences of anastomotic leak
Bridge patient through sepsis, trauma or poor general condition
Later re-anastomosis/reversal possible if distal bowel and patient condition allow

2. Colorectal Cancer and Anorectal Disease

Obstructing colorectal cancer → Decompression/diversion or Hartmann procedure
Rectal cancer after abdominoperineal resection → Permanent end colostomy
Low anterior resection → Temporary protective loop ileostomy/colostomy
Incurable anorectal/pelvic malignancy → Palliative diversion for obstruction, fistula, pain, contamination
Severe anal sphincter dysfunction/incontinence → Permanent diversion in selected cases

3. Emergency Situations

Bowel obstruction with unsafe primary anastomosis
Perforation with peritonitis/fecal contamination
Necrotic/gangrenous bowel
Traumatic bowel injury
Ischemic colitis or mesenteric ischemia after resection
Complicated diverticulitis → Hartmann procedure or diversion in selected cases

4. Inflammatory and Congenital Diseases

Ulcerative colitis → Staged proctocolectomy, ileal pouch-anal anastomosis with protective ileostomy, emergency colectomy
Crohn disease → Temporary diversion for severe perianal disease, fistulas, sepsis, selected resections
Familial adenomatous polyposis (FAP) → Proctocolectomy with ileostomy or pouch surgery
Congenital anomalies → Hirschsprung disease, anorectal malformations, neonatal obstruction in staged surgery

5. Jejunostomy / Enteral Access

Long-term enteral nutrition when oral/gastric feeding is impossible or unsafe
After esophagectomy or gastrectomy to support postoperative nutrition
Upper GI obstruction when stomach/duodenum cannot be used for feeding
Severe dysphagia or aspiration risk when jejunal feeding is preferred

IV. Practical Considerations and Complications

Preoperative Planning

Explain reason, expected duration and possible reversal to patient
Preoperative stoma marking by surgeon/stoma nurse when possible
Choose site visible to patient, away from scars, folds, bony prominences and belt line
Assess sitting, standing and lying positions
Psychological preparation and family/social support are important

Basic Stoma Care

Stoma should be pink/red, moist and well perfused
Educate patient → Pouch change, skin care, output monitoring, diet, hydration, warning signs
Ileostomy patient must monitor fluid and salt intake
High-output ileostomy can cause dehydration and renal failure
Stoma nurse support improves adaptation and reduces complications

Early Complications

Ischemia/necrosis → Dark/black stoma, urgent assessment
Retraction → Stoma sinks below skin, leakage and skin damage
Bleeding → Usually minor mucosal bleeding, but major bleeding must be evaluated
Edema → Common early, should improve
Skin irritation → Leakage, poor appliance fit, ileostomy enzymes
High output → Especially ileostomy/jejunostomy; dehydration, electrolyte disturbance
Obstruction/ileus → No output, pain, distension, vomiting

Late Complications

Parastomal hernia
Prolapse
Stenosis
Retraction and chronic leakage
Peristomal dermatitis/skin ulceration
Fistula or recurrent Crohn disease near stoma
Psychological, sexual and social adaptation problems

Stoma Reversal

Possible only if distal bowel/anastomosis healed and patient is fit
Before reversal → Clinical assessment, endoscopy/contrast study/imaging if needed
Timing depends on indication, sepsis resolution, oncological treatment and patient condition
Reversal also has risks → Anastomotic leak, ileus, wound infection, bowel dysfunction

Exam focus: Define stoma, separate end, loop and double-barrel stomas, know colostomy vs ileostomy vs jejunostomy, list temporary/permanent/emergency indications, and mention preoperative marking, stoma nurse education, dehydration risk with ileostomy, and major complications.