Inguinal hernias

Abstract

Abdominal wall hernias are common, with a prevalence of 1.7% for all ages and 4% for those aged over 45 years.Inguinal hernias account for 75% of abdominal wall hernias, with a lifetime risk of 27% in men and 3% in women. 1 Repair of inguinal hernia is one of the most common operations in general surgery, with rates ranging from 10 per 100 000 of the population in the United Kingdom to 28 per 100 000 in the United States. 2 In 2001-2 about 70 000 inguinal hernia repairs (62 969 primary, 4939 recurrent) were done in England, requiring more than 100 000 hospital bed days.Ninety five per cent of patients presenting to primary care are male, and in men the incidence rises from 11 per 10 000 person years aged 16-24 years to 200 per 10 000 person years aged 75 years or above.3 How do inguinal hernias present?Inguinal hernias present with a lump in the groin that goes away with minimal pressure or when the patient is lying down.Most cause mild to moderate discomfort that increases with activity.A third of patients scheduled for surgery have no pain, and severe pain is uncommon (1.5% at rest and 10.2% on movement).4 Inguinal hernias are at risk of irreducibility or incarceration, which may result in strangulation and obstruction; however, unlike with femoral hernias, strangulation is rare.National statistics from England identified that 5% of repairs of primary inguinal hernia were emergency operations in 1998-9.Older age and longer duration of hernia and of irreducibility are risk factors for acute complications.Gallegos and colleagues studied the presentation of inguinal hernias with a "working diagnosis of strangulation."Only 14 of their 22 patients with an acute hernia had compromised tissue at operation, with one of 439 patients requiring bowel resection.5 Though the study numbers are small, these findings emphasise the rarity of strangulation.A recent larger study estimated the lifetime risk of strangulation at 0.27% for an 18 year old man and 0.03% for a 72 year old man.6 How is an inguinal hernia assessed clinically?A hernia is reducible if it occurs intermittently (such as on straining or standing) and can be pushed back into the abdominal cavity, and irreducible if it remains permanently outside the abdominal cavity.A reducible