What are the guidelines for hernia mesh placement in an adult patient with a history of hernia?

Hernia Mesh Placement Guidelines

Primary Recommendation by Wound Classification

For adult patients with hernias, mesh placement is strongly recommended and should be stratified according to CDC wound classification, with synthetic mesh used for clean (Class I) and clean-contaminated (Class II) fields, biological mesh reserved for contaminated/dirty fields (Class III/IV) with defects >3 cm, and primary repair only for small defects <3 cm in contaminated/dirty fields. 1, 2

---

Decision Algorithm Based on CDC Wound Classification

Clean Surgical Fields (CDC Class I)

No intestinal strangulation, no bowel resection

• Synthetic mesh is the gold standard for all clean field repairs, significantly reducing recurrence rates compared to tissue repair (19% vs 0% in some studies) without increasing wound infection rates 1, 2, 3
• Mesh repair prevents one hernia recurrence for every 46 mesh repairs compared with non-mesh repairs 3
• Both open (Lichtenstein) and laparoscopic approaches (TAPP/TEP) are appropriate, with laparoscopic techniques offering faster recovery and lower chronic pain risk when expertise is available 1, 2, 4
• Short-term antimicrobial prophylaxis is recommended 1, 2

Clean-Contaminated Fields (CDC Class II)

Intestinal strangulation and/or bowel resection WITHOUT gross enteric spillage

• Synthetic mesh can be safely used even with intestinal strangulation and/or concomitant bowel resection, with no significant increase in 30-day wound-related morbidity 1, 2
• This approach is associated with significantly lower recurrence risk regardless of hernia defect size 1, 2
• 48-hour antimicrobial prophylaxis is recommended 2

Contaminated Fields (CDC Class III)

Bowel necrosis and/or gross enteric spillage during intestinal resection

• For defects <3 cm: Primary tissue repair is recommended 1, 2
• For defects ≥3 cm when direct suture is not feasible: Biological mesh should be used 1, 2
• The choice between cross-linked (more resistant to mechanical stress, better for larger defects) and non-cross-linked biological mesh (completely remodels into autologous tissue) depends on defect size and contamination degree 1, 2, 5
• If biological mesh is unavailable, polyglactin mesh repair or open wound management with delayed repair are viable alternatives 1, 5
• 48-hour antimicrobial prophylaxis is recommended 2

Dirty Fields (CDC Class IV)

Peritonitis from bowel perforation

• For stable patients with defects <3 cm: Primary repair is recommended 1, 2
• For stable patients with larger defects: Biological mesh may be used when direct suture is not feasible 1, 2
• For unstable patients (severe sepsis/septic shock): Open management without immediate mesh placement is recommended to prevent abdominal compartment syndrome, with intra-abdominal pressure monitoring and attempt at early definitive closure after stabilization 1, 5
• Full antimicrobial therapy (not just prophylaxis) is required 2

---

Mesh Selection and Technical Considerations

Mesh Types and Properties

• Polypropylene (synthetic) mesh remains the most commonly used material due to durability and tissue compatibility, serving as a scaffold for host tissue ingrowth with fibroblast deposition and angiogenesis 5, 6
• Large-pore synthetic meshes demonstrate superior resistance to infection compared to small-pore designs 5
• Biological meshes become vascularized and remodeled into autologous tissue, with cross-linked variants showing lower failure rates in contaminated fields but higher recurrence rates overall compared to synthetic mesh 5

Mesh Fixation

• In TEP (total extraperitoneal) repair, mesh fixation is unnecessary in almost all cases 4
• In both TEP and TAPP, mesh should be fixed in M3 hernias (large medial) to reduce recurrence risk 4
• Mesh should extend beyond defect boundaries by at least 3 cm for adequate overlap 5
• Fixation can be achieved using tackers or transfascial sutures, avoiding tackers near vital structures 5

---

Approach Selection: Open vs Laparoscopic

Laparoscopic Advantages (When Expertise Available)

• Faster recovery times and earlier return to normal activities (mean 2.87 days sooner) 3
• Lower chronic pain risk 4, 7
• Reduced neurovascular and visceral injuries compared to open repair 3
• Shorter hospital stay (0.6 days shorter on average) 3
• Cost-effective when performed as day surgery with minimal disposables 4
• Lower wound infection rates 5

Open Repair Considerations

• Lichtenstein technique is the most well-evaluated open approach and remains highly effective 4, 6
• Local anesthesia has many advantages in open repair and is recommended when surgeon expertise exists 4
• Operating time averages 4 minutes 22 seconds shorter than laparoscopic (though this difference is uncertain due to study variation) 3
• Less seroma formation compared to laparoscopic approach 3

---

Critical Pitfalls to Avoid

Common Errors in Mesh Placement

• Do not avoid mesh in clean or clean-contaminated fields due to fear of infection - evidence shows mesh is safe and significantly reduces recurrence in these settings 2
• Do not use synthetic mesh in grossly contaminated fields (CDC Class III/IV) - infection rates can reach 21% 5
• Do not use plug repair techniques - incidence of erosion is higher with plug versus flat mesh 5
• Do not select mesh based on weight alone - so-called "low-weight" mesh may have slight short-term benefits but are not associated with better long-term outcomes 4

Risk Factors for Complications

• Mesh infection occurs in 1.9-5% of cases but represents a catastrophic complication, with 72.7% requiring complete mesh explantation 5
• Risk factors significantly associated with mesh infection include: emergency operations, smoking, ASA score ≥3, and longer operative duration 5
• Risk factors for recurrence include: higher BMI, immunosuppressant use, surgical site infections, reoperation, and inadequate mesh width 8

---

Special Populations

Female Patients

• Laparoscopic repair is suggested for women with groin hernias to decrease chronic pain risk and avoid missing a femoral hernia 4

Cirrhotic Patients with Ascites

• Aggressive medical ascites control is essential before elective repair through sodium restriction (2000 mg/day) and diuretic therapy 5
• Emergency surgery carries dramatically increased mortality (OR=10.32) compared to elective repair 5
• TIPSS should be considered to facilitate better ascites control and reduce postoperative complications 5
• Mesh repair is superior to primary suture repair but should only be performed once ascites is controlled 5

Pregnant Women

• Watchful waiting is suggested as groin swelling most often consists of self-limited round ligament varicosities 4

---

Postoperative Management and Outcomes

Recovery Expectations

• Patients are recommended to resume normal activities without restrictions as soon as they feel comfortable 4
• Day surgery is recommended for the majority of groin hernia repairs provided aftercare is organized 4
• Expected recurrence rates with mesh repair range from 0-4.3% 5

Chronic Pain Considerations

• Overall incidence of clinically significant chronic pain is 10-12%, decreasing over time 4
• Debilitating chronic pain affecting normal daily activities ranges from 0.5-6% 4
• Risk factors for chronic postoperative inguinal pain (CPIP) include: young age, female gender, high preoperative pain, early high postoperative pain, recurrent hernia, and open repair 4
• Focus should be on nerve recognition in open surgery, with prophylactic pragmatic nerve resection in selected cases 4