Hernias occur when an organ or tissue pushes through a weak spot in the surrounding muscle or connective tissue. While many types exist, some are less common and present unique diagnostic and treatment challenges. Among these is the Spigelian hernia, a rare abdominal wall hernia often hidden due to its unusual location.
Understanding Spigelian Hernias
A Spigelian hernia forms in a distinct area of the abdominal wall, through the Spigelian fascia. This fascial layer is found between the lateral edge of the rectus abdominis muscle and the linea semilunaris, a curved line that runs from the ribs to the pelvis. Unlike more common hernias that create an obvious external bulge, a Spigelian hernia is often interstitial, developing between layers of the abdominal wall muscles.
The hernia typically involves the protrusion of fatty tissue, a portion of the intestine, or omentum through a small defect in this fascia. Spigelian hernias are rare, accounting for only about 0.12% to 2% of all abdominal wall hernias. Their small size, usually measuring 1 to 2 centimeters, and deep location make them difficult to detect.
Recognizing the Signs
Identifying a Spigelian hernia can be challenging because its symptoms are often subtle and non-specific. Individuals may experience vague abdominal pain or discomfort, which is frequently localized to one side of the lower abdomen. This pain can be intermittent and may intensify with activities that increase abdominal pressure, such as coughing, straining, or heavy lifting. Some people report a sharp pain when bending or standing.
While a palpable lump or bulge may be present, it is often not visibly apparent and can be difficult to feel due to the hernia’s deep position between muscle layers. The lump might only become noticeable when standing and may disappear when lying down. In some cases, a Spigelian hernia may be asymptomatic until it leads to more serious complications.
Causes and Risk Factors
Spigelian hernias develop when a weak spot in the abdominal wall, the Spigelian fascia, forms. This weakness can be present from birth or develop over time due to various factors. Conditions that increase pressure within the abdomen contribute to their formation.
Common factors include chronic coughing and chronic straining during bowel movements. Other risk factors involve heavy lifting, obesity, and pregnancy, which all place increased stress on the abdominal wall. Previous abdominal surgeries or trauma to the area can also create weak points, and the natural weakening of abdominal muscles with aging increases susceptibility. While they can affect anyone, Spigelian hernias are more common in women.
Diagnosis and Treatment Approaches
Diagnosing a Spigelian hernia can be complex due to its hidden location and non-specific symptoms. A physical examination by a healthcare provider may reveal tenderness in the lower abdomen, sometimes accompanied by a subtle bulge that becomes more apparent when the patient stands or performs a Valsalva maneuver. However, imaging studies are often necessary to confirm the diagnosis.
Ultrasound is frequently the initial imaging test. Computed tomography (CT) scans provide more detailed images of the abdominal wall and can accurately identify the hernia’s contents. Magnetic resonance imaging (MRI) may be used for further clarity. Once diagnosed, surgical repair is the recommended treatment to prevent complications.
Surgical options include open repair, which involves a single incision over the hernia site, or minimally invasive laparoscopic surgery, utilizing small incisions and a camera. Robotic-assisted surgery is also an option for repair. During the procedure, the protruding tissue is gently returned to its proper position within the abdomen, and the weakened area is reinforced. This reinforcement often involves placing a surgical mesh to strengthen the abdominal wall and reduce the risk of the hernia returning. Laparoscopic approaches often lead to less pain and a faster recovery compared to open surgery.
Potential Complications
If a Spigelian hernia is left untreated, it carries a risk of serious complications. One such complication is incarceration, where the trapped tissue becomes stuck and cannot be pushed back into the abdominal cavity. This occurs in a significant percentage of cases.
A more serious complication is strangulation. This happens when the blood supply to the incarcerated tissue is cut off, leading to tissue death. The risk of strangulation in Spigelian hernias is high. Symptoms of strangulation include severe, continuous abdominal pain, nausea, vomiting, and changes in bowel habits like severe constipation. Strangulation is a medical emergency that requires immediate surgical intervention to restore blood flow and prevent further damage. Bowel obstruction can also occur if a portion of the intestine becomes trapped, blocking the passage of digested food.