An abdominal wall hernia consists of a protrusion of intra-abdominal tissue through a fascial defect in the abdominal wall. Inguinal hernias are very common (approximately 75% of abdominal wall hernias) with other types of hernias occurring at weak areas of abdominal wall fascia. Typically a hernia consists of visceral contents, a peritoneal sac, and overlying tissue (e.g., skin, subcutaneous tissue). Hernias may be reducible where the protruding contents can be replaced into the abdominal cavity either spontaneously or with manual pressure. Hernias may also be irreducible where the protruding contents are unable to be reduced. There are two classifications of irreducible hernias, incarcerated and strangulated. An incarcerated hernia is irreducible protruding content that is usually due to a small hernia neck. The tissue or contents protruding remain viable and are not causing an obstruction or inflammation. A strangulated hernia is an irreducible hernia in which the blood supply has been compromised. Ischemia, often progressing to necrosis of the protruding tissue or contents, is considered a surgical emergency.
Inguinal anatomy is essential knowledge for the general surgeon. The canal exists between two openings within the abdominal wall known as the internal (deep) inguinal ring and the external (superficial) inguinal ring. The internal inguinal ring is a lateral hiatus within the transversalis fascia, where the external inguinal ring is a medial hiatus within the external oblique fascia. The canal can range from 4 cm to 6 cm in length and is typically cone-shaped in adults. However, in younger children, both the superficial and deep inguinal rings overlap each other. The inguinal canal is bordered anteriorly by the skin, superficial fascia, and the external oblique aponeurosis in its entire extent. Additionally, the fibers of the internal oblique muscle are present on the lateral one-third of the canal. The posterior wall is bounded by the fascia transversalis, extraperitoneal tissue, and parietal peritoneum in its entire extent. Additionally, conjoint tendon (made from transversus abdominis and internal oblique) is located on the medial two-thirds of the posterior wall. The roof is formed by the arching fibers of the internal oblique and transversus abdominis, while the floor is formed by the grooved surface of the inguinal ligament and lacunar ligament. The spermatic cord (males) and round ligament (females) pass through the inguinal canal. The spermatic cord consists of the vas deferens, three arteries/veins, the genital branch of the genitofemoral nerve, lymph vessels, and the pampiniform plexus. The ilioinguinal nerve, which is a content of the inguinal canal, enters the inguinal between the external and internal oblique muscles distal to the deep ring but comes out of the superficial ring along with other structures.
Several additional structures are important to identify during open inguinal hernia repair. The iliopubic tract is an aponeurotic band that begins at the anterior superior iliac spine and courses medially before inserting on the superior aspect of the Cooper's ligament. The shelving edge of the inguinal ligament is the superior attachment of the inguinal ligament to the iliopubic tract. The iliopubic tract forms the inferior border of the internal inguinal ring as it courses medially before becoming part of the femoral canal. Additionally, the lacunar ligament in the medial aspect of the inguinal ligament as it fans out and inserts on the pubic tubercle. Lastly, the conjoined tendon inserts on the pubic tubercle as the culmination of the internal oblique and transversus abdominis fibers.
Two types of inguinal hernias may occur. These are classified as direct and indirect hernia. An indirect hernia passes through the deep (internal) inguinal ring and is located lateral to the inferior epigastric vessels. A direct hernia passes through a weakened area of transversalis fascia in Hesselbach’s triangle (lateral edge of rectus abdominis, the inferior edge of the inguinal ligament, and medial to inferior epigastric vessels). A Pantaloon hernia is a combination of a direct and indirect hernia.
History and clinical examination determine the diagnosis, and no supplemental imaging is needed unless there are extenuating circumstances. CT imaging or ultrasound may be useful in the face of possible bowel obstruction; however, they are not required for surgical intervention.
Inguinal hernias typically are asymptomatic until a bump or swelling of the groin is noted. Some patients may report pain when straining or during heavy lifting. Pain and discomfort are mostly associated with larger hernias usually requiring manual compression for reduction or lying supine with manual compression. Bilateral examination of the groin may reveal a mass that is either reducible or irreducible. An examination should be done supine, as well as, standing, with coughing and straining to identify small reducible hernias. The practitioner palpates the external ring by invaginating the scrotum with an index finger to a point lateral and superior to the pubic tubercle. Coughing or straining during this examination is critical to the palpation of protruding tissue to diagnose a hernia.
A gray-zone or debate regarding the contralateral inguinal exploration and hernia repair exists among the surgeons, especially pediatric surgeons. Contralateral exploration can be performed in children with raised intraabdominal pressure due to increased peritoneal fluid such as children with ventriculoperitoneal (VP) shunt, those undergoing peritoneal dialysis, etc.
There are no absolute contraindications to open inguinal hernia repair. As in all elective surgery, the patient must be optimized medically before surgery.
Some relative contraindications would be:
A standard open surgical tray should be adequate for the procedure. This procedure has many variations that may require special equipment; however, some of the essential equipment has been listed below.
A single operating surgeon may perform this procedure; although, usually there is an assistant. A surgical tech or circulating nurse is required. An anesthesiologist will need to be present as well.
After appropriately selected anesthesia is delivered, the surgeon makes a 5 cm to 6 cm linear incision parallel to the inguinal ligament overlying the proposed region of the external ring. The surgeon dissects until the fibers of the external oblique are identified. The external oblique fascia is opened parallel to the fibers and carried through the external ring revealing the spermatic cord and possible site of a hernia (usually located in an anteromedial position). The ilioinguinal nerve may be found at this juncture. There is great debate on the preservation vs sacrifice of this nerve, and the surgeon's preference or experience dictates the choice. The surgeon then mobilizes the spermatic cord from the pubic tubercle and identifies the hernia sac as indirect or direct. The primary repair of hernia (Herniotomy), which is the routine in children, is rarely performed in adults. However, it is indicated in cases of gross contamination from a strangulated inguinal hernia or in the presence of a femoral hernia. The Lichtenstein tension-free hernioplasty is the preferred method of repair. Many meshes exist, and each mesh procedure varies based on the product. The basic concept is that the mesh will cover the fascial defect and recreate and strengthen the inguinal floor to prevent further hernias following repair. The external oblique fascia may be reapproximated, as per surgeon preference, as well as the re-creation of the external ring.
There are a few popular non-mesh procedures performed by general surgeons. These include Shouldice repair and Bassini repair. The former is an anterior approach associated and is preferred due to low recurrence rates associated with it. A systematic review by Simons et al. concluded that Shouldice repair is the best conventional method of inguinal hernia repair.  The other procedure is Bassini repair. It includes the suturing of the conjoint tendon to the inguinal ligament, thus providing support to the floor of the inguinal canal.
In the present era, most of the surgeons have resorted to mesh hernioplasty, and very few are still performing the conventional non-mesh procedures. Thus, it is very difficult to compare the two techniques. However, a systematic review (published in 2001 and updated in 2018) compares the two techniques in terms of recurrence, complications, operating time, total hospital stay, and the time taken to resume daily activities. It shows that mesh repairs have a low recurrence rate and are associated with a low risk of injury to vital structures including vessels, nerves, and visceral organs. There is a reduced hospital stay associated with mesh repair of inguinal hernia. However, the non-mesh repair is still performed in developing countries due to the issues of cost and availability of mesh. 
Recurrence of hernias is the biggest concern with this surgical technique. Most commonly, the hernia will recur at the pubic tubercle, and without proper technique, this recurrence is more likely. Patient compliance with avoidance of heavy lifting or strenuous activity is also vital to reduce the rate of recurrence. In children, the recurrence of inguinal hernia is noticed in those having poor tissue healing capacity, for e.g. connective tissue disorders, Mucopolysaccharidosis, etc. Chronic pain has been described by many patients and is the main driving point of the great debate between preservation and sacrifice of nerves during dissection.
Surgical repair is recommended electively to avoid incarceration or strangulation. However, reducible inguinal hernias can be safely observed in the elderly population with a sedentary lifestyle or high morbidity for surgery. Open inguinal hernia repair can be performed under general anesthesia, sedation, regional, or local anesthetic.
Postoperatively, the patient is instructed to avoid lifting objects heavier than ten pounds and avoiding strenuous activity for a minimum of four to six weeks. There is much variation in the procedural technique of open inguinal hernia repair. However, the overall goal is accomplished with the basic methods described above.
Inguinal hernias are often first encountered by the primary care provider, nurse practitioner, or internist. In all cases, the patient should be referred to a general surgeon for definitive treatment. All hernias have a potential risk of strangulation and incarceration and thus asymptomatic patients need to follow up. Over the years many types of surgical procedures have been developed to treat an inguinal hernia. The open repair is effective but it also results in significant post-operative pain. Patients do need to be educated that if they do not change their lifestyle or reduce body weight, recurrences can occur.
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