Overview
Definition:
Abdominal wall eventration, often referred to as a large ventral or incisional hernia, is characterized by the protrusion of abdominal contents through a defect in the abdominal wall musculature, where the fascial layers have been disrupted and do not approximate well, leading to a loss of abdominal domain
Reconstruction aims to restore fascial integrity and abdominal wall function.
Epidemiology:
Incisional hernias are a common complication of abdominal surgery, occurring in 5-20% of laparotomies
Risk factors include wound infection, obesity, dehiscence, smoking, and poor nutritional status
Eventration specifically refers to larger defects with loss of abdominal domain, posing greater reconstructive challenges.
Clinical Significance:
Abdominal wall eventration significantly impacts patient quality of life due to pain, discomfort, and functional limitations
More critically, it poses risks of incarceration and strangulation of abdominal contents, leading to bowel obstruction or ischemia
Effective reconstruction is vital for symptom relief, preventing complications, and restoring abdominal wall mechanics.
Clinical Presentation
Symptoms:
Visible bulge or swelling in the abdomen, often exacerbated by coughing, straining, or standing
Pain or discomfort localized to the bulge
Feeling of heaviness or pressure in the abdomen
Difficulty with activities of daily living
Nausea and vomiting if bowel obstruction is present.
Signs:
A palpable defect in the abdominal wall, often with a reducible or irreducible bulge
Skin changes over the hernia may include thinning, discoloration, or ulceration
In cases of incarceration, the hernia contents may be tense and tender
Signs of bowel obstruction may include distended abdomen, absent bowel sounds, and peritonitis.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on physical examination revealing a defect and contents protruding
Imaging studies, such as CT scan, are used to assess the size and contents of the defect, evaluate for loss of domain, and identify associated intra-abdominal pathology
No formal "diagnostic criteria" exist beyond clinical and radiological assessment.
Diagnostic Approach
History Taking:
Detailed history of previous abdominal surgeries, including type of incision and any complications
Onset and progression of the bulge
Associated symptoms like pain, bowel changes, or respiratory distress
Patient's comorbidities (obesity, COPD, diabetes) that may affect surgical outcome
Smoking history.
Physical Examination:
Thorough abdominal examination, including inspection for scars and bulges, palpation to define the defect size and contents, and assessment of reducibility
Examine for signs of incarceration or strangulation
Assess for ascites and evaluate respiratory function.
Investigations:
Ultrasound can be useful for initial assessment
CT scan of the abdomen and pelvis with intravenous contrast is the imaging modality of choice
It helps delineate the fascial defect, quantify the hernia sac contents, assess for loss of abdominal domain (using techniques like the "loss of domain ratio"), and identify adhesions or other intra-abdominal pathology
MRI may be used in select cases.
Differential Diagnosis:
Other abdominal wall masses, lipomas, desmoid tumors, rectus sheath hematoma, seroma, abscess, endometrioma of the abdominal wall, and other types of hernias (e.g., spigelian hernia).
Management
Initial Management:
For asymptomatic, reducible hernias without loss of domain, watchful waiting may be considered
For symptomatic hernias, or those with risk of complications, surgical repair is indicated
Urgent surgical intervention is required for incarcerated or strangulated hernias.
Surgical Management:
Surgical repair aims to close the fascial defect and restore abdominal wall integrity
Options include: 1
Simple suture repair (rarely suitable for large defects)
2
Mesh repair (synthetic or biologic mesh) placed either anterior to the fascia (onlay), between fascial layers (inlay), or posterior to the peritoneum (underlay/sublay)
3
Component separation techniques (e.g., Rives-Stoppa, transversus abdominis release - TAR) which involve releasing the lateral abdominal muscles to achieve primary fascial closure, often combined with mesh
4
Robotic or laparoscopic approaches for less complex defects or component separation
5
Free flap reconstruction for very large or complex defects with tissue loss.
Preoperative Preparation:
Optimizing patient health is crucial
This includes smoking cessation, weight loss in obese patients, nutritional support (especially with low albumin), and glycemic control
Antibiotic prophylaxis is standard
Bowel preparation may be necessary for cases with bowel in the hernia sac
Planning for appropriate surgical approach and mesh material.
Postoperative Care:
Close monitoring for pain, infection, wound complications, and recurrence
Early mobilization is encouraged
Adequate analgesia
Management of drains if placed
Respiratory physiotherapy is important, especially after component separation
Gradual return to activity
Consider prophylactic anticoagulation in high-risk patients.
Supportive Care:
Nutritional support is critical for wound healing
Multidisciplinary team approach involving surgeons, anesthetists, dietitians, and physiotherapists
Pain management strategies should be implemented proactively.
Complications
Early Complications:
Wound infection, seroma, hematoma, mesh infection, mesh extrusion, skin necrosis, anastomotic leak (if bowel resection performed), ileus, pneumonia, urinary retention, deep vein thrombosis (DVT), pulmonary embolism (PE).
Late Complications:
Hernia recurrence, chronic pain, meshoma, bowel obstruction due to adhesions, enterocutaneous fistula (rare), mesh migration, incisional hernia at a new site.
Prevention Strategies:
Meticulous surgical technique, appropriate wound closure, use of prophylactic antibiotics, judicious use of mesh, patient optimization (weight loss, smoking cessation), good postoperative care including early mobilization and respiratory physiotherapy
Careful selection of mesh type and placement technique is vital.
Prognosis
Factors Affecting Prognosis:
Size of the defect, presence of loss of domain, patient comorbidities (obesity, diabetes, immunosuppression), history of wound infection, and surgeon's experience
Recurrence rates vary significantly based on technique, with mesh repairs and component separation generally offering lower recurrence rates than simple suture repair for large defects.
Outcomes:
Successful reconstruction leads to resolution of symptoms, improved quality of life, and reduced risk of complications
Recurrence remains a significant concern, particularly for very large defects or in patients with multiple risk factors
Long-term outcomes are generally good with modern reconstructive techniques, but require diligent follow-up.
Follow Up:
Regular follow-up appointments are essential, typically at 1 week, 1 month, 6 months, and annually thereafter
Follow-up focuses on assessing for signs of recurrence, wound complications, and patient satisfaction
Imaging may be performed if recurrence is suspected clinically.
Key Points
Exam Focus:
Understand the indications for different repair techniques (mesh vs
component separation vs
combined approaches)
Be familiar with the principles of component separation (e.g., TAR) and their role in managing loss of domain
Know the complications of mesh repair and strategies to minimize them
Differentiate between large ventral hernias and simple incisional hernias.
Clinical Pearls:
Always consider loss of domain in large ventral hernias, which dictates the need for component separation or staged repairs
Preoperative optimization is paramount for successful outcomes
Be aware of the potential for prosthetic infection and its devastating consequences
Intraoperative assessment of the integrity of the fascial closure and mesh fixation is critical.
Common Mistakes:
Attempting primary fascial closure for very large defects without considering component separation
Inadequate preoperative optimization of the patient
Poor selection of mesh material or inappropriate placement technique
Insufficient postoperative care leading to complications
Underestimating the risk of recurrence in complex cases.