Risk factors for incisional hernia?
2. Preoperative straining factors:
- 1. Poor surgical technique:
- a. Non-anatomic incision:
- − Battle's pararectal incision damaging number of nerves has high incidence of incisional hernia
- − Vertical incision (midline or paramedian) has high chance of developing hernia than the transverse incision
- b. Method of closure: Layered closure has higher incidence of developing incisional hernia than wound closed in single layer.
- c. Inappropriate suture material: The wound gains about 85% of normal strength in 6 months. Maximum strength is gained in 1 year. Sutures are responsible for maintaining wound strength for 6 months. Wound closed with nonabsorbable suture material are followed by a far lesser incidence of postoperative hernia than wound closed with absorbable suture.
- d. Suturing technique: Closing abdominal incision with suturing under tension causes pressure necrosis of intervening tissues and is an important cause for development of incisional hernia.
- e. Drainage tube: When drain tubes are brought out through the main wound the chance of developing incisional hernia is increased.
Chronic cough, chronic constipation and urinary obstruction.
3. Postoperative complications:
Abdominal distension, cough, respiratory distress due to pneumonia or lung collapse, and postoperative wound infection.
4. General factors
: Age (elderly patients), malnutrition, hypoproteinemia, jaundice, malignancy, diabetes, chronic renal failure, steroid or immunosuppressive therapy and alcoholism.
5. Tissue failure
: Late development of hernia after 5, 10 or more years after operation is usually associated with tissue failure. Abnormal collagen production and maintenance has been shown to be associated with increased incidence of incisional hernia.
Incisional Hernia Staging System?
- Stage I - <10 cm,clean
- Risk: low recurrence, low SSO (Surgical site occurance)
- Stage II - <10 cm and contaminated, 10-20 clean
- Risk: moderate recurrence, moderate SSO
- Stage III - ≥10 cm and contaminated, Any ≥20 cm
- Risk: high recurrence, high SSO
Treatment of incisional hernia?
- Primary repair - defect ≤2 to 3 cm in diameter and there is viable surrounding tissue or in cases in which the hernia was clearly a result of a technical error at the initial operation, such as a suture fracturing.
- Mesh Repair - for Larger defects (>2 to 3 cm in diameter)
Featueres of ideal mesh?
- Chemically Inert
- Resistant to Mechanical stress while maintaining compliance
- Should incite minimal inflammatory reaction
- HypoAllergenic [@ SIMCA]
Features of prolene mesh?
- Polypropylene mesh is a hydrophobic macroporous mesh that allows the ingrowth of native fibroblasts and incorporation into the surrounding fascia.
- It is semirigid, somewhat flexible, and porous.
- Placing polypropylene mesh in an intraperitoneal position directly apposed to the bowel is avoided because of unacceptable rates of enterocutaneous fistula formation.
- The definition of lightweight mesh was arbitrarily chosen at less than 50 g/m2, with heavyweight mesh weighing more than 80 g/m2.
Features of composite mesh?
- This product combines the attributes of polypropylene
- and PTFE by layering the two substances on top of one another. The PTFE surface serves as a permanent protective interface against the bowel and the polypropylene side faces superficially to be incorporated into the native fascial tissue.
- Visceral side that is microporous (3 μm) and an abdominal wall side that is macroporous (17 to 22 μm) and promotes tissue ingrowth.
- This product differs from other synthetic meshes in that it is flexible and smooth.
- Some fibroblast proliferation occurs through the pores, but PTFE is impermeable to fluid. Unlike polypropylene, PTFE is not incorporated into the native tissue. Encapsulation occurs slowly, and infection can occur during the encapsulation process.
Biological materials for hernia repair?
These products are largely composed of acellular collagen and theoretically provide a matrix for neovascularization and native collagen deposition. These properties may provide advantages in infected or contaminated cases in which synthetic mesh is thought to be contraindicated.
Describe the surgical techniques used for the repair of incisional hernia and enumerate the complications of mesh repair. [TU 2062]
Operative techniques of ventral hernia repair?
- Onlay technique -
- - Primary closure of the fascia defect and placement of a mesh over the anterior fascia.
- - Advantage - mesh is placed outside the abdominal cavity, avoiding direct interaction with the abdominal viscera.
- - Disadvantage - large subcutaneous dissection, the increased likelihood of seroma formation, the superficial location of the mesh (which places it in jeopardy of contamination if the incision becomes infected), and the repair is usually under tension.
- Sublay or underlay technique
- - Prosthetic below the fascial components. The mesh can be placed intraperitoneally, preperitoneally, or in the retrorectus (retromuscular) space.
- - With a wide overlap of mesh and fascia, the natural forces of the abdominal cavity act to hold the mesh in place and prevent migration.
Intraperitoneal Onlay mesh (IPOM) repair
- Inlay - in-between fascial edges.
- - The inlay technique, which bridges the fascial defect with mesh, is used only when the onlay and sublay techniques cannot be performed because the fascial defect is too large to primarily close.
- Component separation- Posterior component separation.
- - Anterior component separation
Complications of mesh repair?
- Mesh infection
- Seroma formation
- Intestinal injury during adhesiolysis
What is component separation?
The component separation technique is a type of rectus abdominis muscle advancement flap that allows reconstruction of such large ventral defects. The advantages of the component separation technique are that it restores functional and structural integrity of the abdominal wall, provides stable soft tissue coverage, and optimizes aesthetic appearance.
The component separation technique can restore abdominal wall functionality for defects up to 20 cm at the level of the umbilicus. In some patients with extremely large defects, the component separation technique alone may not allow restoration of the abdominal wall without tension. If the defect is too large to allow the flaps to be brought together at the midline, supplemental mesh can be used to bridge the residual defect.
- Indications for a component separation technique
- ●Repair of large, midline abdominal wall incisional hernias (or open abdomen) that cannot be closed primarily
- ●Repair of recurrent, large midline abdominal wall incisional hernias that have failed suture closure or mesh repair
- ●Reconstruction of abdominal wall defects resulting from trauma or abdominal wall resection related to infection or malignancy
- ●Reconstruction of giant omphalocele
●Extensive destruction of the components of the abdominal wall – Compromise of the superior epigastric artery and/or deep inferior epigastric artery, which are the main blood supply to the rectus muscle flap, is a relative contraindication.
●Contaminated operative field – Although synthetic and biologic mesh have reportedly been used successfully in the presence of contaminated field, active infection is a relative contraindication to mesh placement.
- The success of the component separation technique is attributed to the following five characteristics of the repair
- ●Translation of the muscular layer of the abdominal wall to enlarge the tissue surface area
- ●Separation of muscle layers to allow maximal individual expansion of each muscle unit
- ●Disconnection of the muscle unit from its fascial sheath envelope to facilitate expansion
- ●Use of abdominal wall musculature to cover intra-abdominal contents
- ●Use of bilateral mobilization rather than unilateral advancement for equilibrating forces of the abdominal wall and centralizing the midline
Technique of Anterior component separation?
Anterior component separation involves isolation and division of the external oblique muscle.
●The skin and subcutaneous tissues are carefully elevated from the underlying rectus and external oblique fascia, extending from the costal margin cephalad to the pubis caudally and to the anterior axillary line and iliac crest laterally.
●An incision is made in the external oblique aponeurosis 2 cm lateral to the border of the rectus and external oblique muscles (ie, semilunar line) and extending from the costal margin to the inguinal ligament.
●The external oblique muscle is bluntly dissected from the underlying internal oblique muscle, which should result in approximately 5 cm of advancement in the upper third of the abdomen, 10 cm in the midabdomen, and 3 cm in the lower third of the abdomen. Care is taken not to disrupt the neurovascular supply, located in the plane between the internal oblique and the transversus abdominis muscles.
●If advancement of the musculofascial flap to the midline is not sufficient, the rectus muscle can be dissected free of its posterior sheath. This secondary release should produce an additional 2 to 4 cm of flap advancement. Thus, in the middle third of the abdomen, a total of 20 cm of advancement is often possible
Technique of Posterior component separation?
- Posterior component separation involves isolation and division of the transversus abdominis muscle.
- ●A generous midline incision is made, followed by removal of old meshes (if present) and a complete adhesiolysis.
●The posterior rectus sheath is incised at approximately 0.5 to 1 cm from the medial edge of the rectus muscle. The retrorectus plane is developed laterally until the neurovascular bundle is visualized just medial to the semilunaris line. The neurovascular bundle and any perforators to the rectus muscle are preserved.
●Starting in the upper third of the abdomen, the posterior rectus sheath is incised at approximately 0.5 cm medial to the anterior/posteriorrectus sheath junction to expose the underlying transversus abdominis muscle. The transverse abdominis muscle fibers are then isolated with a right-angle clamp and divided with cautery along the entire length of the abdominal wall (the release) in a cephalad to caudal direction.
●A plane is bluntly developed between the transverse abdominis muscle ventrally and the transversalis fascia/peritoneum dorsally, with extension laterally toward the retroperitoneum/psoas muscle. The plane can reach to the costal margin superiorly and the space of Retzius/Cooper's ligament inferiorly.
●The same procedure can be repeated on the other side when indicated.
●Once a similar release is performed on both sides, the posterior rectus sheaths are reapproximated in the midline with a running, nonabsorbable suture. A sublay mesh is typically placed behind the rectus muscles and secured with full-thickness, transabdominal sutures with the aid of a suture passer. The anterior rectus sheaths are then reapproximated at the midline to restore linea alba anterior/ventral to the mesh.
Short note on Spigelian Hernia? [TU 2072]
- A spigelian hernia occurs through the spigelian fascia, which is composed of the aponeurotic layer between the rectus muscle medially and semilunar line laterally.
- Almost all spigelian hernias occur at or below the arcuate line.
- The absence of posterior rectus fascia may contribute to an inherent weakness in this area.
- Most spigelian hernias are small (1 to 2 cm in diameter) and develop during the fourth to seventh decades of life.
- Patients often present with localized pain in the area without a bulge because the hernia lies beneath the intact external oblique aponeurosis.
- Diagnosis - Ultrasound or CT
- Treatment -
- - Should be repaired because of the risk for incarceration associated with its relatively narrow neck.
- - Primary repair for smaller defects, Larger defects are repaired with a mesh prosthesis.
Boundary of superior lumbar triangle (Grynfeltt)?
- Superior - 12th rib
- Medial - Quadratus lumborum (Paraspinal muscles)
- Lateral - Internal oblique muscle.
- Floor - Transversalis fascia
- Roof - External oblique
Boundary of inferior lumbar triangle (Petit)?
- Inferior - Iliac crest
- Posterior - Latissimus dorsi muscle
- Anterior - External oblique muscle
- Floor - Internal oblique
Describe obturator hernia and its surgical management. [TU 2056]
- The obturator canal is formed by the union of the pubic bone and ischium. This canal is covered by a membrane pierced at the medial and superior border by the obturator nerve and vessels.
- Weakening of the obturator membrane may result in enlargement of the canal and formation of a hernia sac, which can lead to intestinal incarceration and strangulation.
- The patient can present with evidence of compression of the obturator nerve, which causes pain in the anteromedial aspect of the thigh (Howship-Romberg sign) that is relieved by thigh flexion.
- The hernia sac usually contains small bowel, but may contain large bowel, omentum, fallopian tube, or appendix.
- In >90 percent of cases, the diagnosis is made intraoperatively during exploration for bowel obstruction.
- Nonstrangulated obturator hernias can be repaired using mesh via a posterior preperitoneal approach (open or laparoscopic), which provides direct access to the hernia. Reduction of the hernia may require incision of the obturator membrane. When strangulation is suspected, an abdominal approach is used.
- Index finger in deep ring
- Middle finger in Superficial ring
- Ring finger in Sapheneous opening
Deep ring occlusion test?
Hernia is reduced and the deep inguinal ring is occluded by the thumb and patient isasked to cough. Test is positive when no impulse or hernial bulge is seen medial to thedeep inguinal ring on coughing after the deep ring is occluded, suggesting this to bean indirect inguinal hernia
Complete diagnosis of hernia?
- Side: right or left
- Inguinal or Femoral
- Direct or Indirect
- Complete or Incomplete
- Reducible or Irreducible
- Content: Intestine or omentum
- Complicated or Uncomplicated
For example: This is a case of right-sided reducible complete indirect inguinal hernia containing intestine without any features of complication at present.
Bubonocele, funicular and complete hernia?
- Bubonocele - is an incomplete inguinal hernia where the hernial sac is confined to the inguinal canal
- Funicular - hernial sac goes beyond the superficial inguinal ring and reaches upper pole of testis.
- Complete hernia - the hernial contents reaches up to the bottom of scrotum.
- Richter’s hernia - hernial sac contains a portion of the circumference of the bowel
- Sliding hernia - an internal organ composes a portion of the wall of the hernia sac. The most common viscus involved is the colon or urinary bladder. The primary danger associated with a sliding hernia is the failure to recognize the visceral component of the hernia sac before injury to the bowel or bladder.
- Littre’s hernia - containing Meckel’s diverticulum
- Pantaloon (or saddle bag) hernia - having both a direct and indirect inguinal hernial sac lying on either side of inferior epigastric vessels