Overview
Definition:
A parastomal hernia is the protrusion of abdominal viscera through a defect in the abdominal wall adjacent to a surgically created stoma (colostomy or ileostomy)
Repair with retromuscular mesh involves placing a synthetic or biologic mesh in the plane posterior to the rectus abdominis muscles to reinforce the abdominal wall defect.
Epidemiology:
Parastomal hernias occur in 10-50% of patients with an ostomy, depending on the ostomy type, location, and follow-up duration
Risk factors include obesity, advanced age, stoma creation technique, and increased intra-abdominal pressure
They are most common within 2 years of ostomy creation.
Clinical Significance:
Parastomal hernias can lead to symptoms like pain, nausea, vomiting, and difficulty managing the stoma appliance, significantly impacting quality of life
They can also predispose to bowel obstruction, incarceration, and strangulation, requiring urgent surgical intervention and contributing to significant morbidity.
Clinical Presentation
Symptoms:
A visible or palpable bulge adjacent to the stoma, often more prominent when straining or standing
Discomfort or pain around the stoma site
Nausea and vomiting, especially if the hernia is incarcerated
Difficulty fitting or maintaining the stoma appliance seal
Changes in stool output if bowel is compressed.
Signs:
A reducible or irreducible bulge near the stoma, which may be assessed with Valsalva maneuver
Tenderness over the bulge
Signs of bowel obstruction if incarcerated or strangulated, including distension and absent bowel sounds
Stoma appliance leakage.
Diagnostic Criteria:
Clinical diagnosis based on physical examination
Imaging may confirm the diagnosis and assess for complications
No formal scoring system
diagnosis relies on characteristic physical findings and patient history of stoma creation.
Diagnostic Approach
History Taking:
Detailed history of stoma creation: type, location, date, initial complications
Onset and progression of bulge symptoms
Presence of pain, nausea, vomiting, or changes in bowel habits
Previous attempts at hernia repair
Patient comorbidities and risk factors for recurrence.
Physical Examination:
Careful inspection of the stoma site and surrounding abdominal wall, noting any bulge
Palpation of the bulge to assess reducibility, tenderness, and incarcerated contents
Assess for signs of bowel obstruction
Evaluate the integrity of the stoma itself
Examine the entire abdominal wall for other hernias.
Investigations:
Ultrasound of the abdominal wall can identify the defect and protruding contents, particularly useful for assessing reducibility
CT scan is more definitive, demonstrating the fascial defect, hernial sac contents, and relationship to the bowel
It can also identify incarcerated or strangulated bowel
MRI offers good soft tissue contrast
Laboratory tests may be indicated if obstruction or strangulation is suspected (e.g., CBC, electrolytes, lactate).
Differential Diagnosis:
Subcutaneous abscess or hematoma
Desmoid tumor
Direct stoma complications (e.g., retraction, stenosis)
Richter's hernia at the stoma site
Incisional hernia at a distance from the stoma
Lipoma or other abdominal wall masses.
Management
Initial Management:
For asymptomatic or minimally symptomatic hernias, conservative management with optimization of stoma appliance and avoidance of straining may suffice
For symptomatic or complicated hernias, surgical intervention is indicated
Urgent surgery is required for incarcerated or strangulated hernias.
Medical Management:
Primarily supportive
Pain management with analgesics
Management of nausea and vomiting with antiemetics
Bowel rest and nasogastric decompression if obstruction is present
Management of electrolyte imbalances and dehydration.
Surgical Management:
Repair of parastomal hernias is typically performed with mesh reinforcement
The retromuscular (preperitoneal) approach places the mesh posterior to the rectus abdominis muscles, reducing the risk of mesh-related infection and erosion into the bowel or stoma
Techniques include open or laparoscopic approaches
Mesh types include synthetic (polypropylene, ePTFE) or biologic
Careful dissection is crucial to avoid injury to bowel and vascular structures
Fascial closure of the defect is attempted before mesh placement.
Supportive Care:
Postoperative care includes pain control, early mobilization, and gradual resumption of oral intake
Stoma management education for the patient and caregivers is essential
Monitoring for signs of infection, mesh-related complications, and hernia recurrence
Nutritional support may be required for malnourished patients.
Complications
Early Complications:
Wound infection
Mesh infection
Seroma or hematoma formation
Rectus sheath hematoma
Bowel injury during dissection
Stoma necrosis
Injury to visceral or parietal peritoneum
Recurrence of hernia.
Late Complications:
Chronic mesh infection leading to mesh explantation
Mesh extrusion or erosion into the bowel or stoma
Chronic pain
Adhesions
Recurrence of hernia
Stoma complications (e.g., stenosis, prolapse) unrelated to the hernia repair itself.
Prevention Strategies:
Meticulous surgical technique to avoid bowel injury
Appropriate mesh selection and placement in the retromuscular plane
Secure fixation of the mesh
Careful stoma site selection during initial ostomy creation
Patient optimization (weight loss, smoking cessation) preoperatively
Careful closure of fascial defects
Postoperative mobilization and adequate pain control.
Prognosis
Factors Affecting Prognosis:
Hernia complexity (size, incarcerated contents)
Patient comorbidities
Surgical technique employed
Mesh type and fixation
Surgeon's experience
Adherence to postoperative care instructions.
Outcomes:
Successful repair with retromuscular mesh offers a low recurrence rate and improved quality of life
Recurrence rates vary but are generally lower with mesh reinforcement compared to simple suture repair
Significant improvements in pain and stoma manageability are expected.
Follow Up:
Regular follow-up appointments are recommended, typically at 1 week, 1 month, and 3-6 months postoperatively, and then annually
Monitoring for signs of recurrence, mesh-related complications, and stoma issues
Long-term follow-up may be required for complex cases or those with comorbidities.
Key Points
Exam Focus:
Retromuscular placement of mesh for parastomal hernia repair is preferred to minimize mesh-bowel interface complications
Indications for repair include symptomatic hernias, bowel obstruction, and esthetic concerns
Laparoscopic versus open approaches have different advantages and risks.
Clinical Pearls:
Always consider a parastomal hernia in a patient with a stoma presenting with a bulge and symptoms of bowel dysfunction
Assess reducibility and signs of incarceration carefully
Emphasize meticulous dissection in the retromuscular plane to avoid complications
Educate patients thoroughly on stoma care post-repair.
Common Mistakes:
Placing mesh in the preperitoneal or onlay position directly adjacent to the stoma, increasing risk of erosion
Inadequate fascial closure
Ignoring signs of bowel incarceration or strangulation
Inadequate patient selection or preoperative optimization
Insufficient postoperative follow-up and patient education.