Continuing Education Activity

An abdominal wall hernia is 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 occurring at weak areas of abdominal wall fascia. Typically, a hernia consists of visceral contents, a peritoneal sac, and overlying tissue (eg, skin, subcutaneous tissue). This activity describes the pathophysiology that leads to inguinal hernias and reviews the indications, contraindications, and techniques involved in performing open inguinal hernia repair. This activity highlights the role of the interprofessional team in the care of patients undergoing this procedure.

Objectives:

• Identify the anatomical structures pertinent to open inguinal hernia repair.

• Assess the presentation of a patient with an inguinal hernia.

• Determine how to perform an open inguinal hernia repair.

• Communicate some interprofessional team strategies to optimize care coordination and communication to enhance the management of inguinal hernias and improve patient outcomes.

Introduction

An abdominal wall hernia is 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 occurring at weak areas of abdominal wall fascia.[1] Typically, a hernia consists of visceral contents, a peritoneal sac, and overlying tissue (eg, skin, subcutaneous tissue). Hernias may be reducible where the protruding contents can be replaced spontaneously or with manual pressure into the abdominal cavity. Hernias may also be irreducible where the protruding contents cannot be reduced. There are 2 classifications of irreducible hernias: incarcerated and strangulated. An incarcerated hernia has irreducible protruding content that is usually due to a small hernia neck.[2] 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.[3]

Anatomy and Physiology

Inguinal anatomy is essential knowledge for the general surgeon. The canal exists between 2 openings within the abdominal wall: the internal (deep) inguinal ring and the external (superficial) inguinal ring.[4] The internal inguinal ring is a lateral hiatus within the transversal fascia, whereas the external inguinal ring is a medial hiatus within the external oblique fascia. The canal can range from 4 to 6 cm long and is typically cone-shaped in adults. However, in younger children, the superficial and deep inguinal rings overlap. The inguinal canal is bordered anteriorly by the skin, superficial fascia, and external oblique aponeurosis to its entire extent. The internal oblique muscle fibers are also present on the lateral one-third of the canal. The posterior wall is bounded by the fascia transversalis, extraperitoneal tissue, and parietal peritoneum to its entire extent. The conjoint tendon (made from transversus abdominis and internal oblique) is also 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 grooved surface of the inguinal and lacunar ligaments forms the floor. The spermatic cord (males) and round ligament (females) pass through the inguinal canal. The spermatic cord consists of the vas deferens, 3 arteries/veins, the genital branch of the genitofemoral nerve, lymph vessels, and the pampiniform plexus. The ilioinguinal nerve, 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 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 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: direct and indirect. An indirect hernia passes through the deep (internal) inguinal ring and is lateral to the inferior epigastric vessels. A direct hernia passes through a weakened area of transversalis fascia in the Hesselbach 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.

Indications

History and clinical examination determine the diagnosis; no supplemental imaging is needed unless extenuating circumstances exist. CT imaging or ultrasound may be useful in the face of possible bowel obstruction; however, they are not required for surgical intervention.[5][6]

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, 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 palpating protruding tissue to diagnose a hernia.

A gray zone or debate exists among surgeons, especially pediatric surgeons, regarding contralateral inguinal exploration and hernia repair. Contralateral exploration can be performed in children with raised intraabdominal pressure due to increased peritoneal fluid, such as in children with ventriculoperitoneal (VP) shunts, those undergoing peritoneal dialysis, etc. 

Contraindications

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:

• Inability to tolerate general anesthesia; however, this procedure can be performed under local anesthetic
• Coagulopathy
• Obesity (body mass index greater than 35)
• Current tobacco use

Equipment

A standard open surgical tray should be adequate for the procedure. This procedure has many variations that may require special equipment; however, some essential equipment has been listed below.

• Syringe/needle
• Scalpel with blade
• Electrocautery
• Skin forceps, non-traumatic forceps
• Self-retaining retractor
• Metzenbaum scissor
• Mosquito clamps
• Penrose drain/Umbilical tape
• Needle driver
• +/- Mesh (pending selected repair) [7]
• Suture (absorbable/nonabsorbable)

Personnel

A single operating surgeon may perform this procedure, although an assistant usually exists. A surgical tech or circulating nurse is required, and an anesthesiologist also needs to be present.

Preparation

Preparation of an open inguinal hernia repair includes:

• The patient should be preoperatively medically optimized. 
• Laterality should be noted, consented to, and marked in the preoperative area.
• The patient is positioned supine on the operating table. The correct surgical site is clipped free of hair and prepped in the standard sterile fashion.
• The operating surgeon should stand on the side of an inguinal hernia with the assistant standing on the opposing side.[8]

Technique or Treatment

There are 2 options for repair: open and laparoscopic.[8] The open repair is discussed below.[9] Please see the laparoscopic inguinal hernia repair chapter for further information.

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 hernia site (usually 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 a hernia (herniotomy), which is routine in children, is rarely performed in adults. However, it is indicated in cases of gross contamination from a strangulated inguinal hernia or 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 covers the fascial defect and recreates and strengthens 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.

General surgeons perform a few popular non-mesh procedures. These include Shouldice repair and Bassini repair. The former is an anterior approach and is preferred due to its low recurrence rates. A systematic review by Simons et al. concluded that Shouldice repair is the best conventional method of inguinal hernia repair.[10] The other procedure is Bassini repair. It includes suturing the conjoint tendon to the inguinal ligament, thus supporting the inguinal canal floor.

In the present era, most surgeons have resorted to mesh hernioplasty, and very few are still performing conventional non-mesh procedures. Thus, it is very difficult to compare the 2 techniques. However, a systematic review (published in 2001 and updated in 2018) compares the 2 techniques regarding 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 cost and mesh availability issues.[11]

Complications

Recurrence of hernias is the biggest concern with this surgical technique. Most commonly, the hernia recurs at the pubic tubercle, and this recurrence is more likely without proper technique. Patient compliance with avoiding heavy lifting or strenuous activity is also vital to reduce the recurrence rate. In children, the recurrence of inguinal hernia is noticed in those with poor tissue healing capacity, such as connective tissue disorders, Mucopolysaccharidosis, etc. Many patients have described chronic pain, and it is the main driving point of the great debate between the preservation and sacrifice of nerves during dissection. 

Clinical Significance

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, and regional or local anesthetic.[12]

Postoperatively, the patient is instructed to avoid lifting objects heavier than 10 pounds (4.5 kg) and avoid strenuous activity for a minimum of 4 to 6 weeks.[12] The procedural technique of open inguinal hernia repair is highly variable. However, the overall goal is accomplished with the basic methods described above.

Enhancing Healthcare Team Outcomes

Inguinal hernias are often first encountered by the primary care provider 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 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 must be educated that recurrences can occur without changing their lifestyle or reducing body weight.