Evidence-based risk factors for complications and reoperations in inguinal hernia surgery have been defined:
1. Age >80 years: High mortality risk with existing comorbidities; more seromas, urinary retention, and readmissions. Even at age > 60 years, more urinary retention and complications.
2. ASA III and higher: More complications and reoperations, increased mortality risk.
3. Female gender: Increased risk of pain.
4. Obesity: Tendency towards more complications.
5. COPD: More complications, increased mortality in outpatient surgery.
6. Diabetes mellitus: Independent risk factor for postoperative complications.
7. Anticoagulation/antiplatelet agents: 4-fold increased risk of postoperative bleeding. Even after discontinuation of anticoagulant medication, the risk of rebleeding is significantly increased.
8. Immunosuppression/corticosteroid medication: Increased risk of recurrence.
9. Liver cirrhosis: Significant increase in complication rates.
10. Nicotine abuse: Significant increase in general and surgical complication risk.
11. Bilateral inguinal hernia: Increased perioperative risk, therefore no prophylactic operation on a healthy side.
12. Increased complication rate in recurrent procedures and femoral hernias.
13. Preoperative pain frequently leads to acute and then chronic groin pain postoperatively.