Overview
Definition:
Abdominal wall reconstruction (AWR) with transversus abdominis release (TAR) and mesh is a surgical technique used to repair large or complex abdominal wall defects, often involving loss of anterior abdominal wall tissue, by mobilizing fascial planes and incorporating prosthetic mesh to bridge the defect and restore anterior abdominal wall integrity
The TAR component specifically involves releasing the transversus abdominis muscle and its fascial layers to achieve superior tissue advancement for primary closure, thus reducing tension and the need for extensive mesh coverage or component separation.
Epidemiology:
Large abdominal wall defects requiring complex reconstruction arise from various causes including ventral hernias (incisional, umbilical, epigastric), loss of domain after extensive laparotomies (e.g., for trauma, ruptured aortic aneurysms, abdominal sepsis), and massive weight loss
Incisional hernias are the most common type, with reported recurrence rates ranging from 10-30% after traditional repairs
Patients often present with significant morbidity and impact on quality of life.
Clinical Significance:
Effective abdominal wall reconstruction is crucial for restoring abdominal wall function, preventing hernias and evisceration, improving respiratory mechanics, and enhancing the patient's quality of life
Techniques like TAR with mesh allow for tension-free repair in challenging cases, reducing recurrence rates and managing defects that were previously unreconstructible
Mastery of these advanced surgical principles is vital for residents preparing for DNB and NEET SS examinations.
Indications And Contraindications
Indications:
Large ventral hernias (>10-15 cm), loss of domain, recurrent hernias after multiple previous repairs, infected mesh explantation requiring significant tissue mobilization, complex abdominal wall defects (e.g., after necrotizing fasciitis, trauma, or abdominal compartment syndrome).
Contraindications:
Active infection at the surgical site, patient refusal or inability to tolerate major surgery, severe malnutrition and coagulopathy (relative contraindications that require correction), unresectable malignancy involving the abdominal wall
Morbid obesity can be a relative contraindication due to increased risk of wound complications.
Diagnostic Approach
History Taking:
Detailed history of hernia onset, previous repairs (types, dates, outcomes), associated comorbidities (COPD, diabetes, immunosuppression), prior abdominal surgeries, nutritional status, and any symptoms of bowel obstruction or incarceration
Assess functional limitations and impact on daily life.
Physical Examination:
Palpate the abdominal wall to delineate the defect size, identify fascial edges, and assess for any associated masses or skin changes
Evaluate for signs of incarceration or strangulation
Assess the overall integrity of the remaining abdominal wall and the presence of diastasis recti
Assess respiratory function, particularly in patients with large defects or loss of domain.
Imaging Studies:
CT scan of the abdomen and pelvis with the patient supine and in the prone position (or with dynamic imaging) is essential to accurately assess defect size, identify fascial planes, evaluate the extent of tissue loss, assess for loss of domain, and detect any intra-abdominal adhesions or pathology
MRI can be useful for detailed assessment of muscle and fascial anatomy
Ultrasound may be used for initial screening of smaller defects.
Differential Diagnosis:
Distinguish from abdominal masses, desmoid tumors, sarcomas, rectus sheath hematomas, and hernias that can be repaired with simpler techniques
Loss of domain must be differentiated from simple large hernias.
Preoperative Preparation
Optimization:
Nutritional optimization (protein, vitamin C), smoking cessation, glycemic control, management of cardiopulmonary comorbidities
Preoperative antibiotics are typically initiated.
Bowel Preparation:
Mechanical bowel preparation may be considered in select cases, especially if significant intra-abdominal adhesions are anticipated.
Anesthesia Considerations:
Careful anesthetic planning is required due to potential for prolonged surgery, large fluid shifts, and postoperative respiratory compromise
Epidural or regional anesthesia may be utilized adjunctively.
Skin Preparation:
Meticulous skin preparation of the abdominal wall is essential to reduce the risk of surgical site infection.
Surgical Technique Tar With Mesh
Operative Steps:
The procedure typically involves wide undermining of the anterior abdominal wall flaps, meticulous dissection to identify the transversus abdominis muscle and its plane, and release of the posterior leaf of the rectus sheath along with the transversus abdominis muscle
The release extends laterally and superiorly to allow significant fascial advancement
Synthetic or biologic mesh is then placed to bridge the defect, often in a retrofascial or prefascial position, depending on the defect and surgeon preference
The released fascial planes and rectus abdominis muscles are then approximated in a tension-free manner
Fascial closure is reinforced with sutures, and the skin is closed.
Mesh Selection:
Choice of mesh (synthetic vs
biologic, absorbable vs
non-absorbable) depends on defect size, contamination status, and surgeon preference
Large macroporous synthetic meshes are commonly used for permanent reinforcement
Biologic meshes may be considered in contaminated fields or when early mesh resorption is desired.
Fascial Release Details:
The extent of transversus abdominis release is tailored to the defect size
It may involve release along the lateral border of the rectus abdominis muscle, extending superiorly towards the costal margin and inferiorly towards the iliac crest
Careful dissection is crucial to avoid injury to the neurovascular bundles.
Closure Technique:
Progressive tension-free closure of the fascial edges is paramount
Staggered suture placement and use of barbed sutures can aid in achieving this
Careful attention is paid to re-approximating the rectus sheath layers and the transversus abdominis fascia.
Postoperative Care And Complications
Postoperative Management:
Close monitoring of vital signs, fluid balance, and respiratory status
Pain management is critical, often involving epidural analgesia or patient-controlled analgesia
Early mobilization is encouraged
Antibiotics are continued postoperatively
Drain management is guided by output.
Early Complications:
Seroma, hematoma, surgical site infection, wound dehiscence, mesh infection, pneumonia, urinary retention, ileus
Significant fluid shifts and electrolyte imbalances can occur.
Late Complications:
Hernia recurrence, chronic pain, meshoma, enterocutaneous fistula (rare), mesh extrusion.
Prevention Strategies:
Meticulous surgical technique, appropriate mesh selection and placement, aggressive infection prophylaxis, vigilant postoperative monitoring, and patient education regarding activity restrictions are key to preventing complications
Early recognition and management of seromas and wound issues are crucial.
Key Points
Exam Focus:
Understand the anatomical basis of TAR, including the fascial planes involved
Be able to describe indications for TAR vs
other component separation techniques
Know the types of mesh used and their potential complications
Recognize key imaging findings of large hernias and loss of domain.
Clinical Pearls:
Adequate mobilization of fascial flaps is essential for tension-free closure
Intraoperative assessment of defect size and fascial laxity dictates the extent of TAR required
Careful management of fluid shifts and respiratory function is critical postoperatively
Always consider the patient's nutritional status and comorbidities preoperatively.
Common Mistakes:
Inadequate fascial release leading to tension closure and high recurrence rates
Over-reliance on mesh without addressing fascial laxity
Failure to recognize and manage loss of domain
Insufficient preoperative optimization
Ignoring potential complications like seroma or mesh infection.