A direct inguinal hernia refers to an inguinal hernia that protrudes from the medial side of the inferior epigastric artery through the inguinal triangle. Its incidence is lower than that of an indirect hernia, accounting for about 5% of inguinal hernias, and it is more common in elderly males, often occurring bilaterally.

bubble_chart Etiology

The vast majority of direct inguinal hernias are acquired, primarily caused by underdeveloped abdominal walls and weak muscles and fascia in the inguinal triangle. In elderly individuals, muscle atrophy and degeneration widen the inguinal canal, while the supportive and protective functions of the internal oblique, transverse abdominis, and conjoint tendons weaken. When chronic cough, habitual constipation, or difficulty urinating increases intra-abdominal pressure, the transversalis fascia is repeatedly subjected to intra-abdominal stress, leading to injury and thinning. The abdominal organs gradually push forward and protrude, forming a direct hernia. There are no congenital cases.

bubble_chart Diagnosis

It mainly presents as a reducible mass in the inguinal region, appearing as a hemispherical bulge lateral and superior to the pubic tubercle, usually without pain or other discomfort. The hernia becomes visible upon standing and disappears when lying down. The mass does not descend into the scrotum, and due to the wide neck of a direct hernia, incarceration is rare. After reduction, the abdominal wall defect can be directly palpated in the inguinal triangle, with a palpable expansile impulse felt at the fingertips during coughing. If the hernia reappears when the patient stands and coughs while the deep ring is occluded by external pressure, this helps differentiate it from an indirect hernia. Bilateral direct hernias often present with masses close to each other on either side of the midline.

Direct hernias are mostly treated with surgical therapy. The key points of the surgery are to strengthen the resistance of the internal oblique muscle and transversalis fascia to reinforce the posterior wall of the inguinal canal. The repair methods for direct hernias are essentially similar to those for indirect hernias. The Bassini method is commonly used. If a large defect in the transversalis fascia is discovered during the operation and cannot be directly sutured, autologous fascia lata, anterior rectus sheath, or materials like nylon mesh can be used to perform a defect-filling plasty.

Direct hernias are secondary hernias. Preoperative consideration must be given to their causative factors (chronic cough, prostatic hypertrophy, constipation, etc.), which should be addressed. If these factors cannot be controlled or if there are other severe visceral diseases present, surgery is not advisable, and a hernia belt may be used for treatment.