Overview
Definition:
Posterior component separation is a surgical technique used in abdominal wall reconstruction to mobilize the abdominal muscles, specifically the transversus abdominis muscle, by incising its posterior sheath
Transversus Abdominis Release (TAR) is a specific technique that involves incising the posterior rectus sheath lateral to the rectus abdominis muscle, allowing for significant medial advancement of the lateral abdominal muscles to close large fascial defects
This technique is crucial for managing complex incisional hernias and large ventral hernias where primary fascial closure is not feasible.
Epidemiology:
Incisional hernias occur in 5-25% of abdominal surgeries, with larger hernias and multiple previous repairs increasing the risk
Complex ventral hernias requiring component separation, including TAR, are seen in a subset of these patients, often after multiple laparotomies or significant tissue loss
TAR is particularly indicated for hernias with fascial defects exceeding 10-15 cm in width or in patients with compromised abdominal wall compliance.
Clinical Significance:
Posterior component separation with TAR allows for the reconstruction of large abdominal wall defects that cannot be closed with tension-free primary repair
It restores the integrity of the abdominal wall, prevents visceral complications like bowel obstruction and incarceration, improves abdominal wall mechanics, reduces chronic pain, and enhances cosmesis
This technique is vital for surgeons managing complex abdominal wall pathologies and for improving patient quality of life.
Indications
Primary Indications:
Large ventral or incisional hernias with fascial defects > 10-15 cm
Recurrent incisional hernias after multiple previous repairs
Hernias with loss of abdominal domain, where intra-abdominal pressure is significantly elevated
Patients with compromised abdominal wall compliance or prior failed abdominal wall reconstructions
Cases requiring wide fascial mobilization for mesh placement or bridging.
Relative Indications:
Severe abdominal wall distension
Certain congenital abdominal wall defects
Need for substantial anterior fascial advancement
Cases where alternative techniques like bridging or primary repair are deemed insufficient.
Contraindications:
Active surgical site infection
Uncontrolled sepsis
Severe malnutrition or immunosuppression that would compromise healing
Significant coagulopathy
Inability to tolerate prolonged anesthesia
Patients with poor compliance for postoperative management.
Preoperative Preparation
Patient Evaluation:
Thorough history and physical examination focusing on hernia characteristics, previous surgeries, comorbidities, and nutritional status
Assessment of abdominal wall compliance and presence of loss of domain
Imaging studies including CT scan (axial and coronal views) to precisely define hernia defect size, location, tissue planes, and relationship to abdominal organs.
Nutritional Optimization:
Address malnutrition by optimizing protein intake and providing nutritional supplements
Smoking cessation is strongly recommended at least 4-6 weeks preoperatively
Management of comorbidities like diabetes and hypertension.
Imaging And Planning:
CT scan with intravenous contrast is essential for accurate measurement of the defect, identification of the transversus abdominis plane, and assessment of the extent of visceral adhesion
3D reconstruction can aid in surgical planning
Preoperative antibiotics are administered as per standard surgical prophylaxis guidelines.
Informed Consent:
Detailed discussion with the patient regarding the rationale for TAR, the procedure itself, potential risks, benefits, alternatives, and the importance of strict adherence to postoperative protocols, including abdominal binders and activity restrictions.
Procedure Steps
Incision And Exposure:
A curvilinear or elliptical incision is made encompassing the old scar and the hernia sac
The dissection proceeds down to the anterior rectus sheath
The hernia sac is dissected free from the anterior fascia and surrounding tissues
The contents are reduced into the abdomen
If significant adhesions are present, lysis may be required
Care is taken to identify and preserve the rectus abdominis muscles.
Transversus Abdominis Release:
The key step involves meticulously incising the posterior rectus sheath lateral to the rectus muscle, extending from the arcuate line to the costal margin
This dissection plane is avascular and allows for mobilization of the transversus abdominis muscle and its associated fascia
The extent of the release is determined by the size of the defect and the required medial advancement of the lateral abdominal wall components.
Fascial Mobilization And Closure:
Following the TAR, the rectus abdominis muscles and their anterior sheaths are mobilized medially
This provides a significant advancement flap
The posterior rectus sheaths are then closed with non-absorbable sutures
The anterior rectus sheaths are approximated in a relaxed, tension-free manner, effectively bridging the defect
In cases of very large defects or compromised tissue, a prosthetic mesh (synthetic or biologic) may be used in conjunction with or after fascial closure to reinforce the repair.
Mesh Placement If Indicated:
If mesh is used, it is typically placed in the retro-muscular or pre-peritoneal space, external to the newly closed fascial layers
This placement minimizes the risk of mesh-related complications
The mesh is secured to the surrounding tissues with appropriate fixation devices
The subcutaneous tissues and skin are then closed in layers.
Postoperative Care
Pain Management:
Aggressive multimodal pain management including patient-controlled analgesia (PCA), epidural analgesia, or regional nerve blocks is crucial
Regular administration of analgesics is essential to allow for early mobilization and prevent pulmonary complications.
Abdominal Binder And Mobility:
A progressive ambulation protocol is initiated as soon as tolerated
Patients are typically instructed to wear an abdominal binder for several weeks (4-6 weeks) to support the reconstructed abdominal wall and reduce tension on the repair
Gradual return to normal activities is guided by the surgeon.
Monitoring And Complication Surveillance:
Close monitoring for signs of infection, seroma formation, wound dehiscence, and deep vein thrombosis (DVT)
Surveillance for hernia recurrence is performed during follow-up visits
Nutritional support and bowel regimen are continued as needed.
Discharge And Follow Up:
Patients are typically discharged once they are ambulating independently, tolerating oral intake, and have adequate pain control
Follow-up appointments are scheduled at regular intervals (e.g., 2 weeks, 1 month, 3 months, 6 months, and annually) to assess wound healing and monitor for recurrence.
Complications
Early Complications:
Wound infection
Seroma formation
Hematoma
Wound dehiscence
Necrosis of fascial flaps
Bowel obstruction due to adhesions
Respiratory compromise
Deep vein thrombosis (DVT) and pulmonary embolism (PE).
Late Complications:
Hernia recurrence
Chronic pain
Mesh-related complications (infection, extrusion, migration) if mesh is used
Persistent abdominal wall weakness or bulging
Nerve entrapment syndromes.
Prevention Strategies:
Meticulous surgical technique to minimize tissue trauma and ensure adequate blood supply to flaps
Strict aseptic technique
Prophylactic antibiotics
Aggressive pain control to promote early mobilization
Judicious use of drains
Careful selection of mesh and fixation methods if applicable
Patient education on postoperative care and activity restrictions.
Prognosis
Factors Affecting Prognosis:
Size and complexity of the hernia defect
Patient's overall health status, nutritional status, and presence of comorbidities
Surgeon's experience with component separation techniques
Adherence to postoperative care protocols, especially regarding activity and binder use
Prevention and management of complications.
Outcomes:
When performed appropriately for selected patients, posterior component separation with TAR offers a high success rate in closing large abdominal wall defects and reducing hernia recurrence
It significantly improves functional outcomes and quality of life
Recurrence rates vary but are generally lower than with less extensive repairs for large defects
Long-term outcomes depend heavily on the factors mentioned above.
Follow Up:
Long-term follow-up is crucial to monitor for hernia recurrence and late complications
Patients should be educated on signs and symptoms of recurrence and encouraged to report any concerns promptly
Periodic clinical examinations and imaging may be warranted for high-risk individuals.
Key Points
Exam Focus:
Understand the indications for TAR, particularly in large or recurrent hernias with loss of domain
Key steps include identifying the transversus abdominis plane, releasing the posterior sheath, and achieving tension-free closure
Know the critical distinction between anterior and posterior component separation
Be aware of common complications like seroma, infection, and recurrence.
Clinical Pearls:
Preoperative CT scan is your best friend for planning TAR
Accurate measurement of the fascial defect is paramount
Aggressive postoperative pain management facilitates early mobilization, which is key to preventing complications
Consider abdominal binders as an extension of the repair.
Common Mistakes:
Underestimating the size of the defect and overestimating the laxity of the abdominal wall
Inadequate release of the posterior sheath, leading to tension on the repair
Insufficient attention to meticulous dissection in the transversus abdominis plane, risking injury to underlying structures
Poor pain control leading to immobility and increased risk of DVT/PE
Ignoring nutritional optimization and wound healing factors.