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Meckel Diverticulum

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1. Definition and Incidence

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2. Embryology

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3. The "Rule of 2s"

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4. Morphology

• Located on the antimesenteric border of the ileum, 45-60 cm proximal to the ileocecal valve
• It is a true diverticulum (contains all layers of the intestinal wall)
• Ranges from a small bump to a long projection communicating with the umbilicus via a persistent fibrous cord, or (rarely) a patent fistula
• Usual form: wide-mouthed diverticulum, 3-6 cm in length

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5. Ectopic Tissue

• ~50% contain heterotopic tissue
• Most common: gastric mucosa (responsible for acid-induced ulceration and bleeding)
• Followed by: pancreatic mucosa
• Rare: colonic mucosa

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6. Clinical Manifestations

A. Gastrointestinal Bleeding (Most common symptomatic presentation)

• Most common in children ≤2 years of age
• May present as acute massive hemorrhage, chronic anemia, or recurrent self-limited episodes
• Source: acid-induced peptic ulcer in the adjacent ileum caused by ectopic gastric mucosa secreting acid

B. Intestinal Obstruction

1. Volvulus - small bowel twists around the diverticulum attached to abdominal wall by a fibrotic band; may cause strangulation if untreated
2. Intussusception - broad-based diverticulum invaginates and is carried forward by peristalsis; can be ileoileal or ileocolic; presents with obstruction, early vomiting, urge to defecate, and classic currant jelly stools; a palpable mass may be present
3. Littre's hernia - incarceration of the diverticulum in an inguinal hernia

C. Meckel Diverticulitis

• More common in adults
• Clinically indistinguishable from appendicitis (right lower quadrant pain)
• Should be in the differential when appendix is found normal during exploration
• Can progress to perforation and peritonitis
• Key rule: always inspect the distal ileum when the appendix is normal

D. Neoplasms (0.5%-3.2% of cases)

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7. Diagnostic Studies

Note: Surgical intervention should NOT be delayed for imaging in hemodynamically unstable patients with active hemorrhage.

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8. Treatment

Symptomatic Meckel Diverticulum

• Segmental small bowel resection - required for bleeding cases because the ulcer is adjacent to (not within) the diverticulum
• Diverticulectomy - for non-bleeding cases; performed by hand-sewn technique or stapling across the base in a diagonal/transverse line to prevent stenosis
• Laparoscopic resection has equivalent outcomes to open resection (retrospective studies)

Asymptomatic Incidental Meckel Diverticulum

• Controversial in adults
• Historical basis (Soltero & Bill): risk of becoming symptomatic in adults is ≤2%; morbidity of incidental removal was 12% → recommendation was to not resect in adults
• Recent studies argue for resection due to risk of harboring malignancies
• Children found to have Meckel diverticulum during laparotomy: resect
• Factors favoring resection in adults:
  • Age <50 years
  • Male sex
  • Diverticulum length >2 cm
  • Ectopic tissue or palpable abnormalities

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9. Summary Points for Exam

• Most common congenital anomaly of the small intestine (2% of population)
• True diverticulum on antimesenteric border, 45-60 cm from ileocecal valve
• Rule of 2s (2%, 2 feet, 2 inches, 2 years peak age, 2 types of ectopic tissue)
• Most common ectopic tissue = gastric mucosa
• Most common symptom = GI bleeding (children); diverticulitis mimics appendicitis (adults)
• Best diagnostic test = Tc-99m pertechnetate scan in children
• Treatment of bleeding = segmental resection; non-bleeding = diverticulectomy

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Stoma - Classification, Colostomy: Therapeutic Uses and Technique

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PART 1: CLASSIFICATION OF STOMAS

A. By Content Drained

B. By Duration

C. By Configuration

D. By Site of Colostomy

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PART 2: COLOSTOMY - THERAPEUTIC USES

Indications (Bailey & Love + Sabiston)

• To protect a distal anastomosis (usually after anterior resection of rectum)
• After traumatic rectal injury
• To allow healing of a high anal fistula or complex perineal wound
• To defunction an obstructing low rectal cancer prior to long-course chemoradiotherapy

• Acute left-sided colonic obstruction (e.g. sigmoid volvulus, obstructing carcinoma) - as Hartmann's procedure
• Perforated diverticulitis with peritonitis
• Gunshot/stab wound to rectum/colon

• After abdominoperineal resection (APR) for low rectal/anal canal carcinoma - left iliac fossa end-colostomy
• Total proctocolectomy for ulcerative colitis / FAP (when ileal pouch not feasible)
• Severe faecal incontinence in patients unfit for or refusing other procedures
• Bedridden/neurologically compromised patients

• Unresectable rectal cancer causing obstruction
• To prevent obstruction during downstaging chemoradiotherapy in advanced cancers
• Pelvic malignancies invading rectum

• Hirschsprung's disease (in children, as a staged procedure)
• Anorectal malformations
• Radiation proctitis with stricture
• Anal stricture complicating Crohn's disease

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PART 3: SURGICAL TECHNIQUE

Pre-operative

• Stoma siting by stoma nurse: Patient assessed in standing, sitting, and bending positions; avoiding skin folds, scars, bony prominences, and the belt line. Site marked on the infraumbilical fat mound within the rectus abdominis.
• Bowel preparation and antibiotic prophylaxis as appropriate

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Technique 1: END COLOSTOMY (Permanent - e.g., after APR)

1. After bowel resection, the cut end of the sigmoid/descending colon is prepared with adequate mesenteric mobilisation to ensure it reaches the skin without tension
2. A circular disc of skin (2-3 cm diameter) is excised at the pre-marked left iliac fossa site
3. The subcutaneous fat is divided down to the anterior rectus sheath
4. The rectus muscle is split longitudinally (muscle-splitting incision) - NOT cut across
5. The posterior rectus sheath and peritoneum are sharply divided
6. The aperture should admit two fingers comfortably (see figure below)
7. The bowel is delivered through the trephine, ensuring no twisting of the mesentery
8. The colostomy is sutured flush or with slight eversion to the skin (not a spout like ileostomy)
9. End colostomy typically protrudes 0.5-1 cm above skin level

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Technique 2: LOOP COLOSTOMY (Temporary - usually transverse or sigmoid)

1. A loop of colon (most commonly sigmoid; occasionally transverse) is mobilised and brought out through a transverse incision on the anterior abdominal wall (usually right upper or left lower quadrant)
2. The abdomen is closed first
3. A rod or bridge is passed beneath the loop to prevent retraction in the early postoperative period; removed after a few days once adhesions form

1. The colon is incised transversely on the antimesenteric border (about 2/3 of the circumference)
2. The edges of the colonic incision are sutured to the adjacent skin margin (mucocutaneous anastomosis)
3. This creates two openings - proximal (active, efferent) and distal (inactive, afferent)
4. Colostomy function expected within 2-7 days postoperatively

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Technique 3: DOUBLE-BARREL COLOSTOMY (Paul-Mikulicz)

• Used when bowel resection has occurred but patient is too ill for anastomosis
• Both cut ends of the divided colon are brought out as adjacent stomas on the abdominal wall
• Advantage: subsequent closure is easier as ends can be locally mobilised and reanastomosed without full laparotomy

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Key Technical Principles (Sabiston)

• Aperture in abdominal wall must be within rectus muscle (reduces parastomal herniation)
• Large enough to admit two fingers, but not so large as to predispose to hernia
• No tension on the mesentery - for obese patients, full central vascular ligation may be required
• Viability can be assessed intraoperatively with indocyanine green perfusion assessment
• If viability is in question, use a more proximal, well-perfused segment
• Prophylactic mesh around the stoma aperture may reduce parastomal hernia risk by ~40% (recent meta-analysis), though benefit in trials from the last 5 years is less clear

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Post-operative: Colostomy in Left Iliac Fossa

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PART 4: COMPLICATIONS OF STOMA

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Summary

Key surgical teaching: "It is imperative that every stoma must be well made. Proper stoma construction as a prophylactic measure is vastly superior to any therapeutic options to improve upon a suboptimally constructed stoma." - Sabiston

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• Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice, Chapter 95 (Stoma Types, Colostomy)
• Bailey & Love's Short Practice of Surgery, 28th Edition, Chapter 77 (Types of colostomy, Stoma complications)

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Stoma Marking, Classification, Colostomy, and Parastomal Hernia

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SECTION A: STOMA SITING AND MARKING

Who Marks the Stoma?

• Ideally performed by a trained enterostomal therapy (ET) / stoma care nurse preoperatively
• In the absence of an ET nurse, the operating surgeon must perform siting (Fischer's Mastery of Surgery)
• Every gastrointestinal surgeon should be familiar with stoma siting principles

Principles of Stoma Siting

Step-by-Step Stoma Marking

• Skin creases and folds (especially in obese patients)
• Bony prominences (anterior superior iliac spine, costal margin)
• Previous scars or skin grafts
• The belt line and waistband area
• The umbilicus
• Areas not visible to the patient when they look down (patient must be able to see and manage the stoma)

• Within the rectus abdominis muscle - reduces risk of parastomal hernia
• On the infraumbilical fat mound - provides a flat, broad surface for bag adherence (see Sabiston Fig. 95.15 below)
• For ileostomy: right iliac fossa, right paramedian infraumbilical
• For end colostomy: left iliac fossa, left paramedian infraumbilical
• General landmark: midpoint between the anterior superior iliac spine and umbilicus, adjusted for body habitus

Special Considerations

• In obese patients: creases may shift dramatically with position; marking while seated is particularly important
• Clothing preferences (belts, waistbands, religious garments) should be discussed with the patient - stoma must not be under the belt line
• In emergency surgery where marking is not possible: standard landmark of 5 cm lateral to the midline and 4 cm below the umbilicus within the rectus muscle is generally suitable

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SECTION B: CLASSIFICATION OF STOMAS

By Organ/Content

By Duration

By Configuration (Sabiston Fig. 95.18)

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SECTION C: COLOSTOMY - TYPES, THERAPEUTIC USES AND TECHNIQUE

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SECTION D: PARASTOMAL HERNIA

Definition

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Causes and Risk Factors

• Aperture made too large at the time of creation - the most preventable cause
• Stoma placed outside the rectus abdominis muscle (lateral placement dramatically increases hernia risk)
• Tension on the bowel - causes stomal retraction and subsequent enlargement of the defect
• Failure to anchor the bowel to the abdominal wall

• Obesity / high BMI - increases intra-abdominal pressure and makes tissue weaker
• Smoking - impairs collagen synthesis and wound healing
• Poorly controlled medical comorbidities (diabetes, malnutrition, immunosuppression, steroids)
• Weight gain after surgery
• Chronic cough or straining (raised intra-abdominal pressure)
• Previous abdominal wall surgery / scarring

• Risk is directly proportional to length of time the patient has the stoma (Fischer's)
• Rate can reach 50% or more at 5 years

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Clinical Presentation

• A bulge or swelling around the stoma, most visible when the patient coughs or strains
• Difficulty fitting / maintaining the stoma appliance - most common functional complaint
• Appliance bags fit poorly, leading to leakage and peristomal skin excoriation
• Intermittent obstruction of the stoma
• Pain or discomfort around the stoma
• Rarely: acute obstruction or strangulation (surgical emergency)

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Management

Conservative (Non-operative)

• Hernia support belt - reduces symptoms and aids appliance adherence
• Revision of pouching system to accommodate the changed stoma morphology
• Weight loss, smoking cessation, optimisation of comorbidities
• In temporary stomas: conservative management until the stoma can be reversed, with simultaneous repair of the fascial defect at the time of reversal (Fischer's)

Surgical - Indications for Repair

• Significant symptoms (pain, difficulty with appliance)
• Inability to adequately pouch the stoma
• Obstruction, ischaemia, or incarceration of the hernia (emergency)

Surgical Options

• Simple fascial repair around the stoma
• Associated with near 100% recurrence rate - rarely used alone (Bailey & Love)
• Appropriate only as a bridge or in emergency settings

• Stoma is moved to the opposite side of the abdomen
• Previously common, now no longer recommended as parastomal hernia occurs at the same rate at the new site (Bailey & Love)
• The original defect still requires closure

• Mesh infection rate in reported series: only 2-2.6%, and only one case of bowel erosion in 16 studies - much lower than historically feared (Fischer's)
• Retromuscular (sublay) mesh placement is generally preferred over onlay to reduce infection risk
• No RCT has directly compared laparoscopic vs. open repair

• The ideal solution - remove the stoma and restore bowel continuity
• Obliterates the hernia defect and removes the problem entirely
• Not always possible (e.g., permanent colostomy after APR, sphincter deficiency)

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Prophylaxis of Parastomal Hernia

• Place stoma through the rectus abdominis muscle
• Appropriate aperture size (admit two fingers, but no larger)
• Ensure bowel reaches skin without tension

• Large-pore polypropylene mesh placed in the retromuscular space with bowel passing through central hole
• A meta-analysis of 12 RCTs (cited in Sabiston): prophylactic mesh reduces parastomal hernia risk by ~40%
• However, RCTs from the past 5 years show no significant advantage, with comparable complication and mortality rates
• Decision to use prophylactic mesh should be individualised (Sabiston)

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Summary: Parastomal Hernia at a Glance

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• Sabiston Textbook of Surgery, Chapter 95 (Stoma siting, Fig. 95.15, 95.16, 95.17, 95.18, 95.19, 95.20)
• Bailey & Love's Short Practice of Surgery, 28th Edition, Chapter 64 (Parastomal hernia), Chapter 77 (Types of colostomy)
• Fischer's Mastery of Surgery, 8th Edition (Ostomy Marking, Parastomal Hernia)

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SECTION E: STOMA CARE

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1. The Stoma Care Nurse (Enterostomal Therapist / ET Nurse)

• "A stoma is compatible with a normal life" - patients should be told this explicitly preoperatively (Pye's)
• Ileostomy and Colostomy patient associations offer peer support; members meet new patients preoperatively

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2. Preoperative Counselling

• Full explanation of what the stoma is, how it functions, what to expect
• Reassurance regarding body image, relationships, and daily activities
• Introduction to appliance types
• Contact with patient support groups if desired
• Psychological preparation is as important as physical preparation - adapting to life with a stoma can be emotionally taxing

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3. Stoma Appliances

Types of Appliance

Key Points on Appliance Selection

• Bag gasket sizes: 25-100 mm diameter; the aperture is cut to fit snugly around the stoma
• Ileostomy - always use a drainable appliance (liquid, enzyme-rich effluent)
• Sigmoid colostomy - non-drainable bag is suitable (formed faeces)
• Transverse loop colostomy - requires a larger drainable appliance (more liquid output, like an ileostomy)
• Stoma shrinks over the first few weeks; appliance size must be revised accordingly
• Bag should be emptied when half-full to prevent weight detaching the flange

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4. Accessories for Stoma Care

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5. Postoperative Stoma Care - First 24-48 Hours

• Apply a translucent (clear) drainable bag immediately at the end of surgery - allows stoma inspection without bag removal
• Inspect the stoma daily in the first 24-48 hours through the translucent bag for:
  • Colour: healthy stoma should be pink/red and moist
  • Necrosis: black/dusky colour - use a paediatric proctoscope to assess depth of necrosis
  • Bleeding: a viable stoma bleeds when pricked with a needle
  • Retraction: stoma receding below skin level
  • Oedema: common in first week; settles spontaneously
• Colostomy usually acts within 3-5 days (flatus first, then stool)
• Ileostomy acts within 24-48 hours; high output (>1000 ml/day) common initially - monitor electrolytes
• Mucocutaneous sutures (even absorbable) should be removed after day 10

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6. Long-Term Colostomy Management

A. Natural Method

• Some patients develop a predictable, once-daily action (often triggered by a stimulus like tea/coffee)
• Between actions: a simple plastic cap with a belt maintains cleanliness - no bag needed
• Dietary adjustment and antimotility drugs (codeine, loperamide, Lomotil) help establish this routine

B. Appliance Method

• Most common method
• One- or two-piece non-drainable bags used; changed after each action
• One-piece bags can be applied to a Stomahesive base which remains in place for several days

C. Irrigation Method (Colostomy Irrigation)

1. Started 2-4 weeks postoperatively under stoma therapist supervision
2. Patient sits on the toilet
3. A short plastic cone is gently inserted into the stoma (cone prevents perforation risk)
4. The cone is connected to a plastic reservoir suspended at head height
5. 750-1000 ml of water at room temperature are instilled from the reservoir
6. A long plastic sleeve backed by an adhesive flange is applied to the stoma; its open end directed into the toilet bowl
7. The colon evacuates in 10-30 minutes
8. Sleeve is folded and clipped - patient can walk around during residual evacuation
9. Sleeve removed, stoma cleaned, and an adhesive stoma seal applied
10. Repeated every 24-48 hours

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7. Ileostomy-Specific Care

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8. Peristomal Skin Care

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9. Dietary Guidance for Stoma Patients

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10. Psychological and Social Care

• Body image: Patients commonly experience depression, anxiety, and altered body image - particularly young patients and those with permanent stomas
• Sexual function: APR-related nerve damage and stoma placement can impair sexual function; must be discussed preoperatively
• Return to activities: Patients can swim, exercise, travel, and work normally with a well-managed stoma
• Support groups: Ileostomy Association, Colostomy UK - peer-to-peer support is invaluable
• Regular follow-up: Monitor for skin problems, appliance issues, herniation, prolapse, and stenosis

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Summary: Stoma Care at a Glance

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• Pye's Surgical Handicraft, 22nd Edition, Chapter 20 (Stoma care nurses, Appliances, Ileostomy, Colostomy management, Irrigation)
• Bailey & Love's Short Practice of Surgery, 28th Edition, Chapter 77 (Stoma bags and appliances, Stoma complications)
• Fischer's Mastery of Surgery, 8th Edition (Ostomy Marking, Stoma Complications)
• Sabiston Textbook of Surgery, Chapter 95 (Stoma Types, Stoma nurse role)

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1. Definition & Overview
2. Classification tables (by content, duration, configuration, site)
3. Stoma Siting & Marking (4-step process + special patients table)
4. Colostomy - Indications & Operative Technique
5. Stoma Care (appliances, accessories, postop care, irrigation, skin care, diet)
6. Parastomal Hernia (causes, management, all repair techniques with recurrence rates)
7. Complications Quick Reference
8. Exam Revision Key Points

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Stoma Care

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1. The Stoma Care Nurse (Enterostomal Therapist / ET Nurse)

"A stoma is compatible with a normal life" - patients must be told this explicitly before surgery.

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2. Preoperative Counselling

• Full explanation of what the stoma is, how it functions, what output to expect
• Reassurance about body image, relationships, bathing, work, travel, sex
• Introduction to appliance types and demonstration
• Contact with Ileostomy Association / Colostomy UK - peer support from members who have lived with stomas
• Psychological preparation is as important as physical preparation

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3. Stoma Appliances

One-Piece vs Two-Piece

Drainable vs Non-Drainable

Choosing the Right Aperture Size

• Hole in the flange cut to fit snugly around the stoma
• Too small = pressure on stoma → ischaemia
• Too large = effluent contacts skin → excoriation
• Sizes available: 25-100 mm diameter
• Stoma shrinks over the first 4-6 weeks - aperture must be re-measured and resized

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4. Accessories for Stoma Care

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5. Postoperative Stoma Care

Immediate (Day 0-2)

• Apply a translucent (clear) drainable bag at the end of surgery
• Allows daily inspection without removing the bag
• Inspect through the bag for:

Days 3-10

• Colostomy acts within 3-5 days (flatus first, then stool)
• Ileostomy acts within 24-48 hours; initial output often >1000 ml/day - monitor fluid/electrolytes closely
• Water and electrolyte balance must be maintained until output settles
• Remove mucocutaneous sutures at Day 10 (even if absorbable)

Weeks 1-6

• Stoma shrinks progressively - re-measure and resize the appliance aperture regularly
• Aim to change the flange as infrequently as possible (ileostomists: every 4-5 days)
• Teach the patient self-care step by step

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6. Ileostomy-Specific Care

Physiology

High Output Ileostomy Management

• Subacute small bowel obstruction
• Crohn's disease / IBD flare
• Short bowel syndrome
• Drugs: laxatives, antibiotics
• Diet: onions, vegetables, fruits, alcohol

• Loperamide (first line), codeine, diphenoxylate + atropine (Lomotil)
• Oral rehydration solution (high Na content)
• Dietary modification
• Restrict high-oxalate foods (spinach, leafy greens) - reduces renal stone risk

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7. Long-Term Colostomy Management

A. Natural Method

• Relies on a predictable, once-daily action (often stimulus-triggered, e.g. morning tea/coffee)
• Between actions: a plastic cap with a belt maintains cleanliness - no bag needed
• Dietary adjustment + antimotility drugs (codeine, loperamide, Lomotil) help establish regularity

B. Appliance Method (most common)

• One- or two-piece non-drainable bags changed after each action
• One-piece bags applied over a Stomahesive base (base stays in place several days; only the bag is changed)

C. Colostomy Irrigation Method

1. Patient sits on the toilet
2. Attach short plastic cone to the reservoir bag suspended at head height
3. Gently insert the cone into the stoma (cone design eliminates perforation risk)
4. Run 750-1000 ml of water at room temperature from reservoir into the colon
5. Apply a long plastic sleeve (backed by adhesive flange) over the stoma; direct open end into the toilet
6. Colon evacuates over 10-30 minutes
7. Fold and clip the sleeve - patient walks around normally during residual evacuation
8. Remove the sleeve; clean the stoma; apply an adhesive stoma seal
9. Repeat every 24-48 hours

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8. Peristomal Skin Care

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9. Dietary Guidance

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10. Psychological and Social Care

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11. Complications of Stoma Care

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Summary Table: Ileostomy vs Colostomy Care

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What's inside (28 flashcards across 3 sections):

• Ischaemia assessment, retraction, prolapse, stenosis, mucocutaneous separation, high output ileostomy, skin excoriation, allergic dermatitis, fungal infection

• Definition, causes/risk factors, clinical features, repair techniques with recurrence rates, Sugarbaker vs keyhole, prevention

• Master summary table of all complications