Incisional hernias

Question 1

What is an incisional hernia?

In which gender are they most common?

Answer 1

An incisional hernia is an abnormal protrusion of viscus or part of viscus (abdominal contents) through a iatrogenic defect in the fascial layers of the abdominal wall from surgery.

They are most common in men.

Question 2

What percentage of patients undergoing laparotomy will go on to develop an incisional hernia? Over what period of time will these develop?

Answer 2

Rates after laparotomy: 10-20% of patients undergoing laparotomy will eventually develop an incisional hernia.

5% at 5 years, 10% at 10 years

Question 3

What are the three classes of factors that contribute to the development of incisional hernias?

Answer 3

Patient factors
Wound factors
Technique factos

Question 4

List the patient factors that contribute to the development of incisional hernias

Answer 4

• Obesity * highest
• Increased IAP – Obesity, ascites, pregnancy, prostatism, COPD
• Age
• Smoking
• Comorbid
• Malnutrition
• Diabetes mellitus
• Meds – Steroids, immunosuppression, cytotoxicity
• Early return to heavy lifting/ manual labour

Question 5

List the wound factors that contribute to the development of incisional hernias

Answer 5

Local wound complications (e.g. infection, haematoma, foreign body)

Devitalised tissue in wound

Question 6

List the technique factors that contribute to the development of incisional hernias

Answer 6

Incision type – midline vs off midline

Closure Technique – Dissolvable sutures, sutures too tight, sutures too spaced out, wound edges not in apposition.

NB// Ideal = sutures 1cm apart, total length >4x the length of the wound

Placement of drains/ stomas in 1o operative wound

Failure to close fascia of lap port >10mm in size

Question 7

How do incisional hernias present? What percentage will present with incarceration and strangulation?

Answer 7

Range from asymptomatic → emergency presentation

Mild symptoms: Discomfort/ pain with a bulge at surgical scar site

Severe symptoms are associated with complications:
- Incarceration (15%)
- Strangulation (2%)
- Obstruction
- Skin excoriation

Question 8

How are incisional hernias investigated?

Answer 8

Clinical diagnosis

USS / CT

Question 9

What is the role of CT in the management of incisional hernias?

Answer 9

Confirmation of diagnosis when unclear clinically

Pre-op evaluation in large complex ventral hernias

Assess the following:
Exact location and extent of hernia defect
Define contents of hernia sac
Degree of Loss of Domain
Operative planning
Can inform surgical approach
Need for component separation

Question 10

What is the prognosis/natural history of incisional hernias?
-How early can they develop?
-At what postoperative time point are 50% of most incisional hernias apparent?

Answer 10

Hernias can develop as early as 1 month post-op

(c.f. Dehiscence = Develops @ 5-10 days)

Usu occur w/in the 1st year after surgery, but may occur later than this (50% are apparent at 1yr post-op)

Recurrence after repair of a recurrent incisional hernia: >50%

Question 11

What incision locations predispose to formation of incisional hernias?

Answer 11

Choosing Incisions off midline (when possible)

Higher rate of incisional hernia in midline incisions

Upper&raquo_space; lower midline

Question 12

List four principles of suture selection and suturing that contribute to good abdominal wall closure.

Answer 12

1. Continuous running suture
2. Smaller travel 5-10mm
3. Absorbable, monofilament suture
4. 4:1 ratio of suture material to would length

Question 13

Give three methods of abdominal wall closure that can be used to bolster a likely tenuous abdomen

Answer 13

1. Fascial overlap/may style repair - often not possible
2. Prophylactic mesh placement
3. intermittent interrupted non absorbable sutures - not evidence based
4. Fascial release/component separation

Question 14

When is non operative management of incisional hernias acceptable? What is the rate of complications in unrepaired incisional hernias?

Answer 14

Acceptable in asymptomatic, small ventral hernias hernias,

Relatively low rate of complications; approx 1-2% per year in first 5yrs (however still have high lifetime risk of acute complications)

Question 15

What is the location and defect size of incisional hernias with the lowest likelihood of complication?

Answer 15

Those in upper abdomen

<1cm diameter and >7cm diameter

Question 16

What are the contraindications for repair of incisional hernias?

Answer 16

Obesity, BMI >40

Poorly controlled T2DM

Smoking

Other

High-risk patients due to comorbidities: COPD, HF,

Question 17

What are the indications for acute repair of incisional hernias?

What are the indications for elective repair of incisional hernias?

How may patients be preoperatively optimised for repair in the elective setting?

Answer 17

Indication for acute presentation with hernia complications - strangulation or acute incarceration

Indications for elective repair of incisional hernias

Generally, should repair Symptomatic hernias in fit surgical candidate hernias as:

they cont to ↑in size and are difficult to fix when very large

Risk of hernia complications

Symptomatic and unsightly

Pre-op optimization: Stop smoking, lose wt, medical management of ascites

Question 18

When may primary suture repair of incisional hernia be considered?

Answer 18

Consider primary for <2cm hernias
Technique: Direct suture repair +/- Mayo or Keel techniques

Question 19

What is the recurrence rate of a primary repair for large incisional hernias?

What is the recurrence rate in open mesh repair of large incisional hernias?

Answer 19

Recurrence
Primary repair not recommended for larger hernias (recurrence rates 25-50%)

Open mesh repair – Recurrence rates (10-20%)

Question 20

What fascial/mesh overlap is recommended and why?
What are the complications of open mesh repair of incisional hernias?

Answer 20

3cm overlap recommended (as the mesh shrinks)

Complications – Seroma, infection, pain, fistula

Question 21

Define onlay, inlay and sublay mesh placement

Answer 21

Onlay - primary closure of anterior sheath – Mesh superficial to sheath

Inlay - Mesh placed w/in the hernia defect as a bridge and sutured circumferentially

Sublay - (incl. preperitoneal/ retro-rectus) +/- primary closure of anterior sheath – Mesh deep to anterior sheath – Lowest recurrence rates and fewer complications

Question 22

What are the points in favour and against open vs laparoscopic repair of incisional hernias?

Answer 22

Pros:
Open: For very small <1cm and very large >10cm
Shorter operative time

Laparoscopic: Fewer wound complications
Less pain

Cons
Open: Need to wider dissection for mesh insertion

Question 23

What is the rate of recurrence for open vs laparoscopic repair of incisional hernia repair?

Answer 23

There is no difference in the rate of recurrence

Question 24

Give two methods for reducing mesh:bowel interaction

Answer 24

Try to place omentum b/w mesh & intestine to minimize complications … or use “Composite mesh” if mesh is in contact with intestine

Question 25

What are the steps for component separation?

Answer 25

Component Separation If mesh contraindicated Reduce hernia sac, undermine s/c tissue to expose EO laterally beyond midclavicular line, incise EO aponeurosis 1-2cm lateral from the lateral border of rectus (from iliac crest to costal margin), close fascia in the midline w/out tension.

Answer 26

Expect early pain at fixation sites. Bowel injury in incisional hernia ≈ 5%... but ↑ to ≈20% if pt has had prev mesh repair of the hernia Drains usually used to try to minimize post-op seroma formation after open repairs. Seromas usually resolve within 6 months. Currently insufficient evidence to determine whether wound drains are effective in ↓ complications