Indirect inguinal hernia is characterized by intestinal protrusion of the peritoneum and its passage through the internal inguinal ring together with the spermatic cord. It comprises about half of all inguinal hernias and is much more frequent among males. Clinical presentation includes abdominal discomfort and a palpable retractable mass. The diagnosis rests on clinical grounds, while surgery is the main form of therapy.
The clinical presentation of patients invariably includes some form of abdominal discomfort, which is often accompanied by pain, especially during any form of physical activity. Pain when coughing is one of the hallmarks of this condition. A sense of pressure in the groin region, as well as swelling, may be reported . The majority of patients will complain about a prominent bulge in the inguinal region, most often noticed when standing for a prolonged period of time. In the case of indirect inguinal hernia, testicular enlargement is frequent. The indirect inguinal hernia usually develops unilaterally, but a bilateral presentation may occur in some individuals.
The diagnosis of indirect inguinal hernia is generally based on clinical grounds . During a physical examination, the most important part of the diagnostic workup, a retractable bulge is observed and palpated. Palpation should be performed when the patient is both sitting and standing. To confirm the diagnosis, the patient is asked to cough, which will manifest in protrusion of the viscera that can be prevented by external mechanical pressure on the inguinal canal through the testes by the physician. Sometimes, the examination may be difficult to perform (obese patients, those unwilling to cooperate), while unskilled physicians may not differentiate the cause of swelling in the inguinal region. Imaging studies are rarely necessary to confirm the diagnosis, but they may be useful if patients complain of some other symptoms. Abdominal ultrasonography is sufficient in excluding other potential pathologies.
Surgical repair is the only method used in managing indirect inguinal hernia. Insertion of a mesh or sutured repair is the most common method used, either by laparoscopy or open surgery . Studies have established much lower rates of recurrence with the use of a mesh   and is frequently favored over suture repair. There is much debate on the choice of either laparoscopic or open surgery in managing inguinal hernias . Open surgery can be performed by general surgeons, local anesthesia is used and longer recovery time is observed . On the other hand, laparoscopy is shown to result in significantly less postoperative pain and less time away from normal daily activities , which is why both of these procedures are used in general practice.
The overall prognosis of patients with an indirect inguinal hernia is good, as the majority of patients experience mild symptoms that are effectively treated by surgery. In some patients, an inguinal hernia may recur. Indirect forms recur less frequently than direct and factors for recurrent inguinal hernia were established to be female gender and smoking in certain studies . Complications are rarely encountered and are established to occur in less than 1% of patients. However, incarceration or strangulation, the most common complications reported, may have a life-threatening risk for patients, as mortality rates in acute surgery reach up to 7% . Despite the fact that overall mortality rates from surgery are less than 0.5% according to various studies , the diagnosis of an indirect inguinal hernia should be made during the physical examination without hesitation and appropriate surgical procedures, when indicated, should be performed as soon as possible.
Although specific embryologic processes that are involved in the pathogenesis of indirect inguinal hernia have been identified, why this process persists and what are the pathophysiologic mechanisms leading to its development remain unknown. Moreover, persistent (or patent) processus vaginalis and the protrusion of the peritoneum through which indirect inguinal hernia passes was questioned as the sole factor for this abnormality. This brings into question the role of other factors in this condition .
Inguinal hernia repair is considered to be one of the most common surgical procedures performed in medical practice worldwide, with more than 20 million hernia repairs being done every year . Somewhat recent data indicate that more than 700,000 inguinal hernia repairs are being performed in the United States on an annual basis . Certain studies estimate indirect inguinal hernia being slightly more common than direct . Male gender is significantly more affected by this anatomical abnormality, as its occurrence is much more common in males. Additionally, and a significantly increased lifetime risk is established for males - the estimated lifetime risk is around 26%, compared to only 7% for women . Despite these findings, an indirect inguinal hernia is the most common form of a hernia in the female population. In addition to male gender, increasing age is also established in some studies to be a risk factor . On the other hand, the risk of development of an inguinal hernia is reduced among African-American individuals, for unknown reasons .
Indirect inguinal hernias seem to occur due to the incomplete obliteration of processus vaginalis during the testicular descent into the scrotum . During organogenesis, the testes originate in the retroperitoneum and migrate into the deep inguinal ring around the 6th month of pregnancy . Later on, testes slowly start to descend toward the scrotal sacs via the inguinal canal enclosed by a layer of parietal peritoneum, known as processus vaginalis. This process should obliterate shortly after birth, but for some reason, it remains fully preserved, which creates favorable conditions for contents of the peritoneum to protrude through this sac . As a result, the viscera, under various circumstances, mainly due to mechanical pressure, are able to descend through this process into the scrotum and give the characteristic bulging appearance on clinical examination.
Since the events that predispose patients to indirect inguinal hernia occur very early in life, prevention is not possible. Some steps in reducing the risk for complications, however, may be performed. If patients experience even mild symptoms, they should avoid activities which put pressure on the abdominal wall, such as heavy lifting and report to their physician as soon as they notice either swelling or a bulge in their groin or testes. An early diagnosis can facilitate treatment with minimal risk for complications.
An inguinal hernia is considered to be one of the most common surgically managed diseases worldwide, with estimated 20 million surgeries being performed every year . It is considered to be one of the most frequent procedures in the United States, as more than 700,000 hernia repairs are being performed on an annual basis . There are two main types of an inguinal hernia - direct, in which viscera protrude directly through the peritoneal wall and the posterior wall of the inguinal canal; indirect, on the other hand, is distinguished by protrusion through the deep inguinal ring and passage adjacent to the spermatic cord, eventually terminating in the testes. Additionally, the indirect inguinal hernia is recognized by its location in relation to the inferior epigastric artery, by passing laterally from this blood vessel, while a direct hernia passes medially. The pathogenesis of indirect inguinal hernia presumably includes both congenital and acquired factors. During embryonic development, the testes, once they are formed, descend into the scrotum covered by processus vaginalis, a protrusion of the parietal peritoneum created during organogenesis. As the testes descend, processus vaginalis should obliterate, but for some reason, this process does not occur in some individuals, which predisposes visceral protrusion through this processus . This type of hernia is often seen in neonates at birth and infants, but adults are also commonly affected and a significant predilection toward male gender is established. In terms of epidemiology among ethnic groups, African-American individuals are shown to have a reduced risk for the development of hernias in general . Clinical presentation of patients suffering from indirect inguinal hernia usually consists of abdominal pain and discomfort, but the presence of a bulge that retracts on the pressure in the inguinal region is seen in virtually all cases. In most cases, testicular involvement is prominent. In some cases, swelling and significant discomfort may be noted during the physical examination. The differentiation between the two forms of hernias is thought to be of significant importance , primarily because treatment principles may somewhat vary. Physical examination of the inguinal canal can provide means to a definite diagnosis and should be performed when the patient is both standing and sitting . Once the diagnosis is made, surgical therapy is performed in all cases sooner or later. In the setting of acute symptoms and development of complications such as strangulation, surgery is performed immediately, while the debate regarding the timing of surgery in mild or asymptomatic patients is ongoing . This condition can pose a risk for the patient, but an early diagnosis, proper therapy, and follow-up, poses little harm for individuals.
An indirect inguinal hernia is a form of a hernia occurring in the groin region which comprises a protrusion of the organs, mainly intestines, through the abdominal wall and their descent into the scrotum along with the spermatic cord. Normally, during formation of organs in the fetus, the testes slowly descend into their designated place (the scrotum) soon after birth. They descend enclosed in a pouch called processus vaginalis, a part of the sheath enclosing all abdominal organs, the peritoneum. When the testes reach the scrotum, processus vaginalis should degrade, as its function is no longer necessary, but for some reason, this structure persists and enables organs to reside in this pouch that extends to the testes. All types of inguinal hernia, including indirect, are much more common among males while increasing age is an established risk factor, but patients of any age, including neonates, can develop this type of hernia. Patients complain of abdominal discomfort and pain, especially when standing, because of mechanical pressure of abdominal organs. Usually, a bulge in the groin or enlarged testes can be observed during a physical examination. This bulge may be retracted by external pressure from the physician, which is a definite diagnostic sign of the hernia. The bulge, as well as pain, is often aggravated when coughing. This is the reason why patients will be often asked to cough during palpation of the groin and testes. The diagnosis is based on these findings and imaging studies are not necessary. For all patients, surgical repair is indicated. Surgery can be performed by laparoscopy, a procedure that necessitates general anesthesia, somewhat higher rates of recurrence, but lower postoperative pain and quicker return to normal daily activities. Open surgery, on the other hand, is performed under local anesthesia and has lower recurrence rates. Overall, the prognosis is generally good, as complications, such as incarceration (leading to bowel obstruction) and strangulation (obstruction of blood flow to the herniated tissue and is considered as a medical emergency) are very rare. However, they may pose a significant risk to the patient, which is why this condition is usually treated immediately after it is diagnosed.