Inguinal Hernia

Other Names

• Inguinal Hernia
• Direct Hernia
• Indirect Hernia
• Pantaloon Hernia
• Rombert Hernia
• Saddle Bag Hernia

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Background

• This page refers to inguinal hernias, characterized by a defect in the inguinal canal and subsequent protrusion of abbdominal viscera

History

• The first description of an Inguinal Hernia was by Celsus in 1550 BC
• The first case series of inguinal hernias in athletes was published in 1991

Epidemiology

• Lifetime risk is 27% for men, 3% for women
• More common in white than non white patients in the US
• Incidence increases with age, but can affect individuals of all ages
• Bilateral in up to 20% of affected adults
• More common on the right than the left with a ratio of 2:1
  • Possible because of delayed descent of the right testicle, associated patent processus vaginalis
  • Appendectomy scar has been suggested as another reason favoring the right side
• Estimated that 4.5 million people in the united states have an inguinal hernia
• In Jerusalem, there are 18 per 100 men age 25 and greater

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Introduction

Illustration of direct and indirect inguinal hernia. Schematic drawing demonstrates the structures relevant to the occurrence of inguinal hernia. EIA, external iliac artery; GF, genital branch of the genitofemoral nerve; IC, inguinal canal; IEA, inferior epigastric artery; IH, inguinal hernia; IL, inguinal ligament; ILN, ilioinguinal nerve; RAB, rectus abdominis muscle; SC, spermatid cord.

Schematic diagram illustrates the indirect inguinal hernia showing the canal of Nuck and round ligament.

(a) Congenital indirect inguinal hernia and (b) acquired indirect inguinal hernia.

A-Representative scheme of a sagittal section at the neck of an inguinal hernia. B-Representative scheme of the reduction "en masse" of an inguinal hernia. The hernial sac takes an intraabdominal location and the constriction at the hernia neck remains due to fibrotic changes.

Diagram of the inguinal canal (IC) and its contents. The deep inguinal ring is formed by the transversalis fascia, and the IC is lined by the same layers that line the abdominal wall. The external superficial ring is a triangular opening in the oblique aponeurosis. The inferior epigastric artery (a.) and vein (v.) originate from the external iliac artery and vein and lie medial to the internal inguinal ring. Locations of the abdominal wall hernias in relation to the IC are as follows: Indirect inguinal hernias lie lateral to the inferior epigastric arteries (1); direct inguinal hernias lie medial and inferior to the inferior epigastric vessels (2); femoral hernias lie inferior and medial to the femoral vessels (3); and spigelian hernias lie lateral to the rectus abdominus muscle (4)

General

• Characterized by a defect in the inguinal canal with potential protrusion of abdominal viscera
• Can be broken down into medial/direct and lateral/indirect, often treated similarly
• Diagnosis is primarily clinical, with imaging confirming diagnosis/ excluding other pathology
• Some patients can be watched/observed, but generally considered to be a surgical condition

Lateral/ Indirect

• Occur lateral to the inferior epigastric vessels
• Almost all hernias in children are lateral hernias
• More common than medial
• Arise from the internal inguinal ring, presumed to be through a patent process vaginalis
  • Likely from failure of embryonic closure

Medial/ Direct

• Occur medial to the inferior epigastric vessels
• Less common, representing ~25-30% of all inguinal hernias
• Usually occur in men over age 40
• Higher risk to recur after repair
• Medial hernias herniate through a weekend transversalis fascia in the Hesselbach's triangle

Combined

• Mix of both direct/ indirect
• Sometimes called Pantaloon, Rombert, Saddle Bag Hernia

Reducibility

• Reducible: contents can be pushed back into the abdomen with manual pressure
• Irreducible/ Incarcerated: contents can not be pushed back into the abdomen with manual pressure
• Obstructed: lumen of the herniated intestine is obstructed
• Strangulated: blood supply of the hernia contents is compromised, leading to ischemia

Pathophysiology

• Indirect
  • In men, follow the same route as the descending tests
  • They migrate from he abdomen into the scrotum during development of the genitourinary organs
  • One possible reason is the inguinal canal and deep ring are larger to accommodate the descent
  • Generally believed to have a congenital component which requires a potential hernia sac, i.e. processes vaginalis
• Other factors
  • Pinchcock action of internal ring musculature during abdominal muscular straining prohibits protrusion of the intestine into a patent processes
  • Muscle paralysis or injury can disable the shutter effect
  • Transversus abdominis aponeurosis flattens during tensing reinforcing the inguinal floor
  • A congenitally high position of the aponeurotic arch may preclude the buttressing effect
• Iatrogenic
  • Neuropraxic/neurolytic sequelae of appendectomy or femoral vascular procedures may increase incidence
  • Inguinal hernia is a known complication of a radical retropubic prostatectomy, seen in up to 15-21% of patients
  • All lower midline incision of the abdomen also increase risk of inguinal hernia

Etiology

• Indirect
  • Indirect hernia is a congenital hernia regardless of age
  • Occurs because of protrusion of abdominal viscus through an open processes vaginalis
  • Any process which increases intra-abdominal pressure can contribute
• Direct
  • Caused by weakness in the transversalis fascia area of Hasselbech's triangle
• Abnormal collagen
  • Metabolism is though to play a role in the development of primary inguinal hernia
  • Increased type III collagen alters the physical properties of the collagen matrix of the abdominal wall
  • May predispose individuals to the development of inguinal hernias

Anatomy of the Inguinal Canal

• General
  • Short passage that extends inferiorly, medially through the inferior part of the abdominal wall
  • Superior and parallel to the inguinal ligament
  • Serves as a pathway by which structures can pass from the abdominal wall to external genitalia
  • Potential weakness in the abdominal wall, common site of herniation
• Walls
  • Anterior: aponeurosis of the external oblique, reinforced by the internal oblique muscle laterally
  • Posterior: transversalis fascia.
  • Roof: transversalis fascia, internal oblique, transversus abdominis
  • Floor: inguinal ligament, thickened medially by the lacunar ligament
• Contents
  • Spermatic cord (males): contains neurovascular and reproductive structures of the tests
  • Round ligament (female):
  • Ilioinguinal nerve: contributes to sensory innervation of the genitalia
  • Genital branch of the genitofemoral nerve

Associated Conditions

• Varicose Veins
• Benigh Prostatic Hypertrophy
• Hemorrhoids
• Chronic Obstructive Pulmonary Disease
• History of open appendectomy
• Perotoneal Dialysis
• Thoracic or abdominanal aortic aneurysm

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Risk Factors

Patient Risk Factors

• Male Gender
• Old Age
• Patent processes vaginalis
• Systemic connective tissue disorder
• Body mass index
  • High BMI increases intraabdominal pressure, risk of recurrence
  • Low BMI may also increase risk of hernia
• Possibly, Benig Prostatic Hypertrophy
• Family history of groin hernia
• Matrix metalloproteinase (MMP) abnormalities
  • Including Ehlers–Danlos, Marfan’s, Hurler’s, and Hunter’s syndromes

External Risk Factors

• Tobacco use
  • Increases risk of recurrence, less clear regarding primary hernia
• Things that increase intra-abdominal pressure
  • Daily lifting
  • Standing/walking
  • Coughing
  • Jumping

Sports

• Weight Lifting
  • Note, weight lifters do NOT have an increased risk of inguinal hernias

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Differential Diagnosis

Differential Diagnosis Groin Pain

• Intra-articular / Hip Etiology
  • Femoroacetabular Impingement
  • Acetabular Labral Tears
  • Injuries to the Ligamentum Teres
  • Hip Osteoarthritis
  • Avascular Necrosis of the Femoral Head
  • Osteochondral Defect of the Hip (Loose Bodies)
  • Hip Microinstability
• Extra-articular Causes
  • Pelvic Stress Fracture
  • Osteitis Pubis
  • Sports Hernia (Athletic Pubalgia)
  • Avulsion Fractures of the Pelvis
  • Snapping Hip Syndrome
  • Iliopsoas Tendinopathy
  • Rectus Femoris Strain
  • Rectus Abdominal Strain
  • Myositis Ossificans
  • Iliac Apophysitis (AIIS, ASIS, Iliac Crest)
  • Inguinal Hernia
  • Femoral Hernia
  • Adductor Tendonitis
  • Adductor Strain
• Neuropathic/ Nerve Entrapment Syndromes
  • Obturator Neuropathy
  • Femoral Neuropathy
  • Iliohypogastric Nerve Injury
  • Genitofemoral Nerve Injury
  • Ilioinguinal Nerve Injury
  • Meralgia Paresthetica (Lateral Femoral Cutaneous Nerve)
  • Pudendal Neuralgia
• Axial/Spinal Etiology
  • Lumbar Disc Disease
  • Facet Arthropathy
  • Sacroiliitis
  • Sacroiliac Joint Dysfunction
• Pediatric Considerations
  • Legg Calve Perthes Disease
  • Slipped Capital Femoral Epiphysis
  • Transient Synovitis of the Hip
  • Idiopathic Chondrolysis of the Hip
• Intra-abdominal Considerations
  • Abdominal Aortic Aneurysm
  • Appendicitis
  • Diverticulitis/ Diverticulosis
  • Lymphadenitis
  • Inflammatory Bowel Disease
• Genitourinary Considerations
  • Ovarian/Testicular Torsion
  • Ectopic Pregnancy
  • Nephrolithiasis
  • Epididymo-Orchitis
  • Ovarian Cyst
  • Pelvic Inflammatory Disease
  • Round ligament pain
  • Urinary Tract Infection
  • Endometriosis
  • Prostatitis
  • Testicular cancer

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Clinical Features

History

• Often develop slowly overtime, but can happen suddenly
• Patients will endorse a bulge on either side of the inguinal hernia
• Pain can be burning, gurgling or aching
• Patients will complain of more vague groin pain
• Worse with bending over, coughing, lifting, straining
• Pain and swell in the testicles if the intesctines descent into the scrotum
• Incarcerated hernias may not be manipulated thorugh the fascial defect
• Pain nausea and vomiting may be presence, suggesting a bowel obstruction
• Tenderness of an incarcerated hernia indicates strangulatoin
• Systemic toxicity can occur from ischemic bowel

Physical Exam

• Careful inspect the area for bulges while the patient is standing
  • This should be repeated after asking the patient to strain/ valsalva
• It can be more challenging in female patients
• The hand should be placed over the groin area which might feel a bulge or impulse during valsalva
• Introduction of a finger into the scrotum might feel an impulse

Special Tests

• Valsalva Maneuver: asking the patient to cough/strain may recreate the bulge

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Evaluation

Mixed direct and indirect inguinal hernia, that is, pantaloon hernia. (a, b) Axial CT images demonstrate hernial openings (white-dotted line) on either side of the original of the epigastric vessels (white arrow). (c, d) Coronal CT images confirm both hernial openings (arrowheads) located in both superior triangles of the quadrangular myopectineal orifice (white-dotted line)

Clinical

• Most early inguinal hernias can be diagnosed by careful physical examination
• Imaging may be useful to exclude other possible diagnosis

Ultrasound

• Useful to diagnose in patients who report symptoms without a palpable defect
• Can differentiate incarcerated hernia from pathologic lymph node or other firm, palpable mass
• Sensitivity is more than 90%, specificity 82% to 86%

CT

• Role of CT scan is not well defined

MRI

• Most sensitive detection of a hidden hernia in a patient with clinical suspicion for hernia
• Useful to differentiate femoral and inguinal hernias

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Classification

EHS Groin Hernia Classification

Traditional Classification

• Direct
• Indirect
• Combined

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Management

Open Inguinal Hernia Releasing Incisions. Indirect, direct, and femoral hernia spaces are outlined in red. The optimal sites for releasing incisions are marked with blue.

Prevention

• Reducing standing/walking from ≥6 h to <4 h daily about 30% of primary lateral hernia repairs can be prevented

Nonoperative

• Until recently, elective surgery was recommended for all inguinal hernias
  • This was due to fear of incarceration/strangulation
• However, most surgeries are performed at the patients request
• Some surgeons consider watchful waiting a reasonable option for minimally symptomatic hernias
  • Risk of chronic post herniorraphy pain is greater than 10%, risk of incarceration is less than 0.2% per year

Operative

• Indications
  • Many reducible hernias
  • All incarcerated or strangulated hernias
• Technique
  • Open (tension free mesh, tension free suture, tension suture)
  • Laparoscopic

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Rehab and Return to Play

Rehabilitation

• Needs to be updated

Return to Play/ Work

• There are no universally accepted or evidenced based return to play criteria for athletes following inguinal hernia repair
• A few studies suggest the following
  • Most athletes can resume full athletic activity between 2 and 6 weeks
  • Following open mesh repair/ laparoscopic repair, mean return to play was 4 to 6 weeks
  • Some elite athletes return as early as 2 weeks

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Prognosis and Complications

Prognosis

• Overall, the prognosis for athletes returning to sports is excellent
• Most return in 4-6 weeks following surgical repair

Complications

• Strangulation
• Incarceration
• Tumors masquerading as hernia
• Inability to return to sport

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See Also

• Groin Pain Main
• Physical Exam Groin
• Groin Anatomy Main

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