Overview
Definition:
Ventral hernia component separation is a surgical technique used to close large ventral abdominal wall defects by mobilizing and advancing the abdominal wall muscles
Posterior component separation (also known as the transverse abdominis release or TAR) involves incising the posterior rectus sheath to release the transverse abdominis muscle and its associated fascial layers, allowing for greater medial excursion of the rectus abdominis muscles and wider closure of the fascial defect.
Epidemiology:
Ventral hernias, particularly incisional hernias, are common, with reported rates of 3-11% after laparotomy
Large and recurrent ventral hernias often present with significant loss of domain, making primary closure challenging and necessitating advanced reconstructive techniques like component separation.
Clinical Significance:
Failure to adequately close large ventral hernias can lead to impaired respiratory mechanics, reduced core strength, chronic pain, and an increased risk of incarceration and strangulation
Component separation techniques, especially posterior TAR, offer a valuable option for achieving tension-free fascial closure in complex cases, improving patient quality of life and reducing recurrence rates.
Indications
Indications For Tar:
Posterior TAR is indicated for large ventral hernias (typically >10-15 cm), hernias with loss of domain, recurrent hernias after previous repairs, or when primary repair would require excessive tension
It is particularly useful when the rectus abdominis muscles are widely separated, making traditional methods insufficient.
Contraindications:
Absolute contraindications are rare but include active infection at the surgical site, severe malnutrition, and significant comorbidities that render the patient unfit for major surgery
Relative contraindications might include extensive prior abdominal surgery with dense adhesions or a history of abdominal wall ischemia.
Patient Selection:
Ideal candidates are those with adequate nutritional status and no active systemic illness
A thorough preoperative assessment, including imaging to evaluate the defect size and extent of fascial separation, is crucial for selecting appropriate patients and planning the surgical approach.
Preoperative Preparation
Nutritional Optimization:
Ensuring adequate protein intake and addressing any nutritional deficiencies is vital for wound healing
This may involve dietary counseling and nutritional supplements for several weeks preoperatively.
Smoking Cessation:
Patients are strongly advised to quit smoking at least 4-6 weeks before surgery to reduce the risk of wound complications and improve healing.
Bowel Preparation:
Depending on the approach and surgeon preference, mechanical bowel preparation may be instituted the day before surgery.
Anesthesia Considerations:
Anesthesia management should focus on adequate pain control and potential for prolonged surgery
Epidural analgesia may be considered for postoperative pain management and early mobilization.
Procedure Steps Posterior Tar
Incision And Dissection:
A curvilinear incision is made to encompass the hernia sac
The dissection proceeds down to the anterior rectus sheath
The hernia sac is dissected from the anterior rectus sheath and abdominal contents are reduced.
Posterior Fasciotomy:
The key step involves incising the posterior rectus sheath lateral to the rectus muscle
This incision is extended superiorly and inferiorly to release the transverse abdominis muscle and its fascial attachments, allowing the rectus muscles to be mobilized medially.
Mesh Placement:
A large piece of prosthetic mesh (e.g., polypropylene, ePTFE) is typically placed in an underlay fashion, ensuring adequate overlap with healthy anterior fascia
It is secured to the posterior rectus sheath and surrounding healthy abdominal wall.
Fascial Closure:
With the rectus muscles now mobilized medially, the anterior rectus sheath is closed in a single layer using a strong, non-absorbable suture
This closure is performed with significant medial advancement of the rectus muscles, achieving tension-free approximation.
Wound Closure:
Subcutaneous tissues are closed in layers, and the skin is closed using staples or sutures
Drains are often placed in the preperitoneal or subcutaneous space to manage fluid collection.
Postoperative Care
Pain Management:
Aggressive pain management is crucial, often involving patient-controlled analgesia (PCA) with opioids, supplemented by oral analgesics and regional blocks (e.g., epidural or transversus abdominis plane blocks).
Ambulation And Mobilization:
Early ambulation is encouraged to prevent deep vein thrombosis (DVT) and pulmonary complications
Patients are advised to avoid heavy lifting and strenuous activity for at least 6-8 weeks.
Wound Care:
Regular wound inspection for signs of infection, dehiscence, or seroma formation is essential
Drains are typically removed when the output is less than 20-30 ml per 24 hours.
Respiratory Support:
Pulmonary hygiene exercises, including deep breathing and incentive spirometry, are vital to prevent atelectasis and pneumonia, especially given the potential for reduced respiratory excursion post-surgery.
Complications
Early Complications:
Seroma formation, hematoma, wound infection, skin necrosis, and mesh infection are potential early complications
Acute mesh-related complications like extrusion are rare but possible.
Late Complications:
Recurrent hernia formation, chronic pain, mesh migration, bowel obstruction due to adhesions, and chronic seroma are possible late sequelae
Nerve entrapment and fascial dehiscence can also occur.
Prevention Strategies:
Meticulous surgical technique, appropriate mesh selection and placement, adequate antibiotic prophylaxis, aggressive pain control to facilitate early mobilization, and patient education on activity restrictions are key to preventing complications
Careful dissection and tension-free closure are paramount for reducing recurrence.
Prognosis
Factors Affecting Prognosis:
The prognosis is influenced by the size of the defect, patient comorbidities, adherence to postoperative instructions, and surgical technique
Recurrence rates can vary significantly but are generally lower with successful component separation compared to primary repairs of large defects.
Outcomes:
Successful component separation with posterior TAR can lead to durable closure of large ventral hernias, restoration of abdominal wall integrity, and improvement in quality of life, including reduced pain and better functional capacity.
Follow Up:
Regular follow-up appointments are recommended, typically at 1 week, 1 month, 3 months, 6 months, and 1 year postoperatively, to monitor wound healing, assess for early signs of recurrence, and address any patient concerns
Long-term follow-up may be indicated based on individual risk factors.
Key Points
Exam Focus:
Posterior TAR is a crucial technique for managing large ventral hernias
Understanding the anatomy of the transversus abdominis plane and its release is essential
Differentiate it from anterior component separation
Know indications, contraindications, and potential complications.
Clinical Pearls:
Adequate medialization of the rectus muscles is key for tension-free closure
Secure mesh fixation to the posterior sheath minimizes the risk of displacement
Aggressive pain management is vital for early recovery and mobilization.
Common Mistakes:
Inadequate release of the posterior sheath leading to tension on closure
Insufficient mesh overlap or fixation
Premature return to strenuous activity by the patient
Not considering loss of domain and its implications on respiratory function.