Spigelian hernia has been named after Adriaan van den Spieghel who described the linea semilunaris. Spigelian hernias are hernias of the semilunar line and are mostly located where the latter crosses the semicircular line of Douglas (also known as arcuate line) (location of least resistance). Often the hernia sac is interparietal, in other words it penetrates the transversus abdominis and internal oblique muscles and then courses posterior to the intact aponeurosis of the external oblique or it is found within the rectus sheath along the lateral edge of the rectus abdominis. For this reason, spigelian hernias are hard to detect and quite often are detected only when incarcerated. Once diagnosed, surgery should always be recommended.
Spigelian hernias are rather uncommon and represent only 0.12% of all hernias of the abdominal wall. They become manifest between the fourth and seventh decade of life, with no gender predominance (men : women = 1 : 1.18).
Minimally invasive surgery is an excellent option with significantly lower morbidity and shorter hospital stay. Either transperitoneal or extraperitoneal access may be gained.