From the standpoint of the general surgeon, a hernia is a structural defect that leads to protrusion of the abdominal contents through the abdominal wall or groin. A hernia is reducible if the abdominal contents can be returned to their normal position, and irreducible if not. The latter represents an incarcerated (i.e., “trapped” like a prisoner) and can be acute or chronic. If acute the process can lead to strangulation of the blood supply and gangrene.
Protrusion with or without pain is a hernia until proven otherwise. Physical exam is the most sensitive diagnostic modality, and imaging is usually unnecessary. Pain especially in the groin without protrusion is usually not a hernia, but exceptions can occur.
The past three decades have witnessed the routine usage of mesh, which can be described as a fiberglass net. Repair tension is minimized by bridging a defect with mesh; the trick is to sew it in flat and tight like a tennis racket—but not too tight. A common analogy is the use of reinforcing steel rods in concrete. The advantages of mesh (less pain,avoidance of tension, less recurrence, and quicker recovery) are far more significant than theoretical infection risks which are very low. Risk factors for recurrence include obesity, heavy lifting, and tobacco usage.
An umbilical hernia is usually the smallest and easiest type of hernia to repair. The defect represents an umbilical cord defect that never closed. The procedure is done as an outpatient and most patients return to work in one week.
Two types of groin hernias exist: femoral and inguinal (by far the most common.) Inguinal hernias are classified as indirect (congenital) or direct (acquired.) Reconstruction is more difficult, and return to work is dictated by the degree of occupational heavy lifting. The procedure is done as an outpatient
Ventral hernias are classified as primary or secondary (i.e., incisional.) Large incisional hernias are sub-categorized as simple or complex. Large complex ventral hernias can be very difficult to repair and are often done in a tertiary (University) care center.