Protrusion of abdominal viscera through Hesselbach's triangle, inguinal canal and anulus inguinalis superficialis is referred to as direct inguinal hernia. Thus, hernial opening differs from that observed in cases of indirect inguinal hernia.
The most common symptoms that prompt IH patients to present to their physician are a palpable mass in the inguinal area or scrotum or acute, localized pain upon heavy lifting, bending, coughing, defecation or micturition. Mass and pain may only be noticeable in determined positions. Laying down usually provides relieve. Whereas in some cases, intermittent pain is the only symptom , painless hernias have been described, too . Complaints generally aggravate after physical stress, particularly if related to increased intra-abdominal pressure, standing for prolonged periods of time or after eating. Chronic hernia may be associated with few and only mild symptoms, but they tend to grow.
When compared with indirect IH, direct IH are usually less extensive and rarely reach the scrotum. Protruded viscera are typically palpable in the groin. Although less likely, direct IH does not rule out the possibility of strangulation. Systemic symptoms like fever, chills, nausea and vomiting in an IH patient hint at an incarceration and require immediate medical attention. This also applies to abdominal swelling and the inability to pass stool, gases or urine.
Because the majority of IH patients are elder men that present with comorbidities facilitating the development of direct IH, symptoms associated with these diseases may dominate the clinical picture. Prostate enlargement, chronic constipation and chronic pulmonary disorders are among the most frequently observed primary diseases that contribute to hernia formation.
Because both congenital connective tissue disorders as well as increased intra-abdominal pressure due to comorbidities affect both sides' Hesselbach's triangle, a significant share of IH patients presents with bilateral hernia.
Diagnosis of an IH is based on physical examination. If no palpable mass can be detected in the inguinal region, standing, bending and coughing may be required to force abdominal viscera to protrude through the hernial opening.
Diagnostic imaging, particularly sonography, plain radiography and computed tomography scans may be applied to obtain further information as to the origin of protruded organs and possible incarceration. Moreover, imaging techniques are often applied in obese individuals because hernia may not be palpable in these patients. Administration of contrast agents may significantly augment the sensitivity of imaging methods. Care has to be taken upon selection of a suitable contrast agent in patients who are suspicious for perforation or tissue necrosis. Uncomplicated cases of IH do not require workup by means of imaging: The method of choice to determine if a patient does indeed suffer from IH has long since been surgical exploration. However, the possibility of diagnosing IH by means of herniography should not be underestimated and may avoid unnecessary surgical interventions  .
Laboratory analysis of blood samples is generally not required. However, such analyses may be of importance in patients with systemic complications and comorbidities affecting suitability for surgical intervention and risk of relapse.
Surgical repair is the method of choice to treat IH. Only repositioning of protruded viscera and closure of the hernial opening effectively prevent possibly fatal tissue incarceration. Generally, the hernial opening, the weak spot in the abdominal wall, will be additionally reinforced with synthetic tissue.
Surgical intervention and herniorrhaphy is even recommended to most patients presenting with asymptomatic hernia, but conservative treatment may be considered in such cases . Patients should be advised of the risk to become symptomatic, though.
Watchful waiting is usually not recommended in pediatric patients. However, in children, open surgery may be challenging and the risk of permanent damage to anatomical structures passing the inguinal canal is higher than in adult men. Laparoscopic repair may be a valuable alternative to open surgery in such cases if the size of the hernia does not disagree with this technique .
Any strangulated or irreducible IH needs to be considered an emergency and requires immediate surgical intervention.
Many patients experience pain after herniorrhaphy and require analgesics. Also, physical activity should be limited for several weeks. Relapses are not uncommon and require another surgical intervention.
Prognosis associated with direct IH is generally good. However, a significant share of patients presents comorbidities that may have triggered the hernia and that have a worse prognosis.
A direct IH results from the fact that intra-abdominal pressure exceeds the resistance of those anatomical structures forming the Hesselbach's triangle within the medial inguinal fossa. This situation may be provoked either by an increased intra-abdominal pressure or by weakened connective tissue and muscles of the abdominal wall.
With regards to the former, chronic cough (very common in patients suffering from asthma, chronic obstructive pulmonary disease, cystic fibrosis, tuberculosis and in smokers), chronic constipation, urinary retention (in men, most likely due to prostatic hyperplasia or neoplasms) as well as heavy physical strains may all force the patient to build up high intra-abdominal pressure. Similarly, ascites, obesity and pregnancy may be associated with an elevated pressure on the abdominal wall.
On the other hand, anatomical anomalies, e.g., diminished resistance of the abdominal wall due to genetic disorders and undescended testes, may allow for direct IH even without increased intra-abdominal pressure. An increased risk of direct IH has also been shown for certain surgical interventions in the lower abdomen.
Anatomic differences account for high male-to-female ratios in IH patients: Both genders dispose of this weak spot in their abdominal walls, the Hesselbach's triangle. However, in women, the ligamentum teres uteri passes through the inguinal canal, constitutes an additional barrier and therefore reinforces this particular area of the abdominal wall. Furthermore, a non-obliterated processus vaginalis does not contribute to direct IH, but the fact that the man's testicles descend through the inguinal canal leave it wider than in women. Thus, if abdominal viscera pass the Hesselbach's triangle, they may encounter a preformed room that is much more distensible in males than in females. All these anatomical features highly predispose men for this pathology. It has been estimated that less than one out of five patients presenting with direct IH is female.
Age is another factor affecting direct IH incidence. Both connective tissue as well as musculature weaken the abdominal wall and render the Hesselbach's even more prone to give way. According to recent estimates, incidence rates increase more than 10-fold from adolescent males to elder men.
Morbidity and mortality associated with IH mainly result from incarceration of protruded viscera. Venous congestion and hemorrhagic infarction is more common in incarcerated tissues than compression of arteries. However, both conditions contribute to considerable reduction of supply with oxygen and nutrients. Thus, soft tissue gangrene develops and subsequent release of toxins may have lethal systemic consequences . This serious complication is more frequently observed in patients presenting with indirect IH since the hernial opening is wider in direct IH.
Before protruded viscera undergo necrosis, functional impairment manifests. Indeed, difficulties to pass stool or urine may indicate a strangulated hernia before other specific symptoms become noticeable.
Skin of inguinal regions and scrotum may also be compromised by IH. Large hernias significantly stretch the skin, cause tissue damage, inflammation, pain, erythema and swelling. Post-operative management of IH patients should therefore include skin care.
Prolonged pressure on testis, vas deferens as well as vasculature and nerves supplying these anatomical structure may negatively affect spermatogenesis and fertility. In most cases, reduction in fertility is transient and resolves upon successful repair of the hernia. The individual risk of infertility after IH seems to depend on the surgical technique applied .
Individuals can neither change their genetic predisposition for developing IH nor avoid certain pulmonary, gastrointestinal or urogenital diseases. However, behavior and life style largely contribute to the individual risk of IH and thus, according measures may reduce the likelihood of developing this condition. Lifting of heavy objects should be avoided and if unavoidable, such objects should be lifted from ones knees and not from ones back. Any sports requiring building up abdominal pressure should be executed following a professional's instructions regarding breathing. It is generally recommended to maintain a healthy body weight. Smokers should stop their habit. Any pathologic condition that constitutes a risk factor for IH should be adequately treated to avoid prolonged or repeated augments of intra-abdominal pressure.
Both men and women dispose of bilateral inguinal canals and a variety of veins, arteries and nerves passes through it in both genders. However, in men, both testes descend through the ipsilateral inguinal canal before birth and create what is designated the processus vaginalis, a peritoneal diverticulum. This physiological process results in wider inguinal canals in males than in females.
Any protrusion of abdominal viscera into the inguinal canal is referred to as inguinal hernia (IH). In most cases, the hernial opening corresponds to the above described processus vaginalis which should obliterate after testes descent, but which persists in some individuals. Such an hernia is called indirect inguinal hernia. On the other hand, parts of the gastrointestinal tract may protrude through a weak spot of the abdominal wall and come to rest within the inguinal canal. However, there is no physical connection between protruded tissues and the inside of the processus vaginalis and thus, these hernias rarely reach the scrotum and are generally less voluminous than those described before. The aforementioned weak spot is designated Hesselbach's triangle, in honor of the German anatomist who first described it more than 200 years ago . This type of hernia is called direct inguinal hernia.
Because protrusion of abdominal viscera occurs lateral to the epigastric vessels in case of indirect IH but medial to these vessel in patients suffering from direct IH, the terms lateral and medial hernia are sometimes used instead of indirect and direct hernia.
Protrusion of parts of the gastrointestinal tract is most common. However, any soft tissue may pass the Hesselbach's triangle and inguinal canal and consequently, ureter, urinary bladder, urethra, connective tissue and fat may be encountered in an IH sac .
The medical term inguinal hernia (IH) refers to the protrusion of abdominal viscera into the inguinal canal, an anatomical structure that measures a few centimeters in length and is located in the groin.
Men dispose of a wider inguinal canal than women because their testicles pass this canal when descending from their fetal intra-abdominal position into the scrotum. Under physiological conditions, the path taken by men's testicles obliterates afterwards. If that's not the case, soft tissues, mainly parts of the gastrointestinal tract, may pass through this same opening and come to rest in the scrotum. This type of IH is called indirect inguinal hernia.
However, there's a weak spot in the abdominal wall in very close proximity to the inguinal canal. It is called the Hesselbach's triangle. Due to distinct etiological factors, this spot may give way and allow abdominal viscera to pass through. Maybe one could imagine this spot as a semi-open side entrance to the inguinal canal: Soft tissues may protrude through this opening but due to anatomical restrictions such hernias are usually smaller than indirect IH. They are called direct inguinal hernia.
The Hesselbach's triangle may yield under increased intra-abdominal pressure or, less frequently, under physiological pressure if connective tissue disorders cause structural anomalies.
An augmented intra-abdominal pressure, in turn, may result from chronic cough (due to asthma, chronic obstructive pulmonary disease, cystic fibrosis, tuberculosis or smoking), chronic constipation, urinary straining (common in elder men with prostate disorders) and heavy lifting. Obesity and pregnancy may similarly trigger IH.
Although some IH are asymptomatic, many patients either note a palpable mass in their groin or feel pain when adopting certain positions, standing for prolonged periods of time or lifting heavy objects. Bulge and pain may either be intermittent or persistent, neither experience rules out an IH.
Diagnosis of direct IH is generally based on physical examination. The physician may require the patient to stand, bend or cough in order to provoke protrusion of tissues. Diagnostic imaging techniques, namely sonography, plain radiography or computed tomography scans, may be applied if doubts remain as to the origin and condition of protruded tissues.
While watchful waiting may be the treatment of choice in some patients who present with small, asymptomatic IH, the vast majority of patients will need to undergo surgical repair of the abdominal wall. Replacement of protruded tissues into the abdominal cavity is the only way to avoid strangulation and incarceration.