A Spigelian hernia is a hernia

Hernia

A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm....

 through the spigelian fascia

Fascia

A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...

, which is the aponeurotic layer between the rectus abdominis muscle

Rectus abdominis muscle

The rectus abdominis muscle, also known as the "six pack", is a paired muscle running vertically on each side of the anterior wall of the human abdomen . There are two parallel muscles, separated by a midline band of connective tissue called the linea alba...

 medially, and the semilunar line

Linea semilunaris

The linea semilunaris is a curved tendinous line placed one on either side of the rectus abdominis.Each corresponds with the lateral border of the rectus, extends from the cartilage of the ninth rib to the pubic tubercle, and is formed by the aponeurosis of the internal oblique at its line of...

 laterally. These hernias almost always develop at or below the linea arcuata

Arcuate line (anterior abdominal wall)

The arcuate line of the abdomen, Linea semicircularis or Douglas' line is a horizontal line that demarcates the lower limit of the posterior layer of the rectus sheath. It is also where the inferior epigastric vessels perforate the rectus abdominus.Superior to the arcuate line, the internal oblique...

, probably because of the lack of posterior rectus sheath. These are generally interparietal hernias, meaning that they do not lie below the subcutaneous fat but penetrate between the muscles of the abdominal wall; therefore, there is often no notable swelling.

Spigelian hernias are usually small and therefore risk of strangulation

Strangulating

Strangulating is the process of constricting blood vessels which cause arrest in the flow of blood to a tissue....

 is high. Most occur on the right side. (4th-7th decade of life). Compared to other types of hernias they are rare.

Symptoms and diagnosis

Patients typically present with either an intermittent mass, localized pain, or signs of bowel obstruction

Bowel obstruction

Bowel obstruction is a mechanical or functional obstruction of the intestines, preventing the normal transit of the products of digestion. It can occur at any level distal to the duodenum of the small intestine and is a medical emergency...

. Ultrasonography or a CT scan can establish the diagnosis, although CT scan provides the greatest sensitivity and specificity.

Treatment

These hernias should be repaired because of the high risk of strangulation; fortunately, surgery is straight-forward, with only larger defects requiring a mesh prosthesis.Varied Spigelian hernia mesh repair techniques have been described, although evidence suggests laparoscopy results in less morbidity and shorter hospitalization compared with open procedures. Mesh-free laparoscopic suture repair is feasible and safe. This novel uncomplicated approach to small Spigelian hernias combines the benefits of laparoscopic localization, reduction, and closure without the morbidity and cost associated with foreign material.

Eponym

Adriaan van den Spiegel

Adriaan van den Spiegel

Adriaan van den Spiegel, name sometimes written as Adrianus Spigelius was a Flemish anatomist who was born in Brussels. For much of his career he practiced medicine in Padua, and is considered one of the great physicians associated with that city...

, a surgeon

Surgeon

In medicine, a surgeon is a specialist in surgery. Surgery is a broad category of invasive medical treatment that involves the cutting of a body, whether human or animal, for a specific reason such as the removal of diseased tissue or to repair a tear or breakage...

-anatomist born in Brussels

Brussels

Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

, described this hernia. The first publication was in 1645, twenty years after Spiegel's death.