Spigelian hernia.

The diagnosis of spigelian hernia presents greater difficulties than its treatment. The clinical presentation varies, depending on the contents of the hernial sac and the degree and type of herniation. The pain, which is the most common symptom, varies and there is no typical pain of spigelian hernia. Findings to facilitate diagnosis are palpable hernia and a palpable hernial orifice. Large, easily palpable spigelian hernias are not a diagnostic problem. It is small hernias and hernial orifices that are overlooked because they are masked by the subcutaneous fat and an intact external aponeurosis. In the absence of a palpable orifice or sac, persistent point tenderness in the spigelian aponeurosis with a tensed abdominal wall most strongly suggests the diagnosis. Spigelian hernia can be ruled out in patients without palpable tenderness. Ultrasonic scanning can be recommended for verification of the diagnosis in both palpable and nonpalpable spigelian hernia. The hernial orifice and sac can also be demonstrated by computed tomography, which gives more detailed information on the contents of the sac than does ultrasonic scanning. The treatment of spigelian hernia is surgical, and the risk of recurrence is small. A gridiron incision is excellent for operations for palpable hernias. If the hernia cannot be palpated preoperatively, preperitoneal dissection through a vertical incision is recommended. This gives good exposure, facilitates hernioplasty, and permits preperitoneal exploration and treatment of other abdominal wall hernias. The incision is also suitable for exploratory laparotomy, which should be performed on patients with abnormal ultrasonographic or computed tomographic findings in whom no palpable hernia can be detected preoperatively.