1.1 General Principles

1.2 Inguinal Hernia

1.3 Femoral Hernia

1.4 Umbilical Hernia

1.5 Incisional Hernia

1.6 Spigelian Hernia

1.7 Obturator Hernia

1.8 Videos for further understanding

General Principles

Definition

• A hernia is an abnormal protrusion of an organ (or part of an organ) through its containing body wall Table 2.1.

Table 2.1 Classification of Hernias

Incidence (Relative)

• Groin > ventral > pelvic > flank
• Classical distribution (statistics are always changing)
• Inguinal (~75% of all hernias
• repaired) Femoral (~10% of all hernias repaired) Umbilical (~5% of all hernias repaired)
• Ventral: 33% incisional, 67% primary

Uncommon Hernia Types

Richter’s Hernia

• Partial thickness of bowel trapped within sac, usually the antimesenteric part of the bowel Figure 2.1. Leads to partial bowel obstruction with vomiting but the patient continues to pass flatus.

Sliding Hernia

• A peritoneal covered structure such as the colon or urinary bladder slides down extra-peritoneally with the peritoneum adjacent to it and forms the wall of the hernial sac.

Figure 2.1 Richter’s hernia.

Pantaloon Hernia

• Both a direct and indirect hernia occurring simultaneously.

General PathologyReducible

• Contents re-enter their containing cavity (usually the abdomen) either spontaneously or with manipulation.

Irreducible or incarcerated

• Hernia persists despite manipulation.
• Leads to obstruction (i.e., bowel)
• Narrower neck of hernia (i.e., femoral) increases risk
• At risk of strangulation

Strangulated

• Ischemia and necrosis of hernia contents
• Decreased venous/lymphatic flow → increased bowel oedema → impeded arterial flow → infarction → necrosis

Inguinal Hernia

Epidemiology

• Male: female = 8:1
• Median age at presentation
• Men: 50-70 years old
• Women: 60–80 years old

Figure 2.2 Hernia types.

Types of Inguinal Hernia

• Can be direct or indirect according to their anatomical relationship to the inferior epigastric artery, inguinal canal, and Hesselbach’s triangle Figure 2.2.

Indirect Hernias Pass In the Inguinal Canal

• Leave the abdomen via the deep inguinal ring to follow an oblique course through the inguinal canal
• Emerges through the superficial ring, may descend into scrotum.
• May extend to the tunica vaginalis surrounding the testis
• The peritoneal sac may derive from a patent or re-opened processus vaginalis

Direct Hernias Protrude Directly Through (Anteriorly) the Transversalis Fascia In Hesselbach’s Triangle

Pantaloon hernia describes a combination of both

Surgical Anatomy

• Inguinal ligament
• Runs from ASIS to pubic tubercle.
• Hasselbach’s triangle borders
• Inferior–inguinal ligament. Lateral–inferior epigastric artery.
• Medial–rectus sheath
• Deep inguinal ring
• Made from an invagination of transversalis fascia.
• Lies 1–2 cm superior to the midpoint of the inguinal ligament.
• Superficial inguinal ring
• V-shaped defect in external oblique aponeurosis.
• Lies superomedial to the pubic tubercle.
• Inguinal canal: Runs from the deep to superficial ring.

Borders of inguinal canal

• Anterior Wall
• Entire canal–external oblique aponeurosis.
• Lateral third–internal oblique.
• Posterior Wall
• Entire canal–transversalis fascia.
• Medially–conjoint tendon.
• Superior Wall
• Internal oblique, external oblique, and transversus abdominis (conjoint tendon).
• Inferior Wall
• Inguinal ligament (rolled external oblique aponeurosis).

Figure 2.3 Inguinal canal.

Table 2.2 Contents of the Inguinal Canal

Clinical Presentation

• Can often be incidental/asymptomatic.
• Presentations range from a lump +/− pain to acute strangulation/obstruction.
• Discomfort can be worse at the end of day/after prolonged standing.
• Classic indirect takes a few hours to present. Classic direct presents on standing.

Differential Diagnosis

• Femoral hernia
• Lymphadenopathy/lymphoma
• Metastatic lymphadenopathy
• Hydrocele
• Testicular torsion
• Femoral artery aneurysm
• Undescended testicle

Investigations

• Bedside
• Clinical examination is often diagnostic.
• Right : Left incidence = 2 : 1
• Bulge is often better appreciated on standing/cough/Valsalva.
• Incarcerated hernias with visible/palpable lump will persist upon lying down.
• NB: Be sure to examine the scrotum.
• Direct/indirect differentiation is often intraoperative.
• Routine bloods including WBC, CRP, U&E, lactate.
• Groin US–may be useful if occult hernia or obstruction is suspected.

Management

• Emergency
• Strangulated/Obstructed hernias should undergo surgical repair within 6–8 hours from onset to prevent bowel loss.
• Conservative
• Watchful waiting is an option in some cases:
• Elderly patients or significant co-morbidity.
• Uncomplicated, mild symptoms (future elective repair).
• Annual risk of incarceration 0.3% per year.
• Surgical
• Symptomatic inguinal hernias in adults should be repaired.
• Groin pain with exertion.
• Inability to perform ADLs.
• Chronic incarcerated hernia.
• Open Mesh (Tension-Free) Or Non-Mesh (Tissue Approximation) Repair
• Tension- free repair is the preferred operation
• Utilizes a patch of non-absorbable mesh to strengthen the posterior wall of the inguinal canal/deep ring.
• NB: Mesh cannot be used in presence of infection.
• Can be done under local anaesthesia plus sedation, but preferred way is under general anaesthesia
• Laparoscopic Herniorrhaphy
• Cannot be performed if:
  • • • Infection or contamination, Ascites, Patient's intolerance to GA
• Previous Surgery Involving Preperitoneum (I.E., Laparotomy, Lscs, Tah).
• Main indications: Bilateral hernia, recurrent hernia.
• Totally extraperitoneal (TEP) repair and transabdominal preperitoneal patch (TAPP) repair, both are considered tension-free repairs and use a mesh.
• Anatomical sites that must be taken under consideration during laparoscopic hernia repair are depicted in Figure 2.4

Figure 2.4. Concept of inverted Y and 5 triangles of importance during laparoscopic hernia repair

Needs redrawing

Source:Furtado M, Claus CMP, Cavazzola LT, Malcher F, Bakonyi-Neto A, Saad-Hossne R. SYSTEMIZATION OF LAPAROSCOPIC INGUINAL HERNIA REPAIR (TAPP) BASED ON A NEW ANATOMICAL CONCEPT: INVERTED Y AND FIVE TRIANGLES. Arq Bras Cir Dig. 2019 Feb 7;32(1):E1426. Doi: 10.1590/0102-672020180001e1426. PMID: 30758474; PMCID: PMC6368153.

Complications of Inguinal Hernia Repair

• Scrotal haematoma/seroma
• Wound infection
• Urinary retention
• Chronic pain/paraesthesia in the scrotum (or labia majora in females) due to injury of the ilioinguinal nerve (5–10%)
• Chronic pain/paraesthesia on the side of the thigh due to injury of the femoral lateral cutaneous nerve during laparoscopic hernia repair, also known as meralgia paraesthetica (very rare)
• Testicular atrophy caused by damage to the testicular artery (<1%)
• Recurrence <5%
• NB: Infection is the most important risk factor.
• Poor operative technique
• Chronic cough, constipation or bladder outlet obstruction. Avoid heavy lifting for 6–8 weeks post-procedure

Femoral Hernia

Epidemiology

• Female > male
• ~30% of all hernia repairs in women, <1% of all hernia repairs in men
• More common in later life (>70 years old)

Figure 2.5. Femoral hernia

https://www.osmosis.org/learn/Femoral_hernias:_Clinical_sciences

Eric Needs redrawing

Figure 2.5. Borders of femoral canal

https://teachmeanatomy.info/lower-limb/areas/femoral-canal/

ERIC: PLEASE INDCIATE SOURCE FOR 2.6 above (incorrectly listed as 2.5) - Also poor quality.

Figure 2.6. Boundaries of the femoral triangle

Surgical Anatomy

Table 2.3 Boundaries of the Femoral Triangle

Table 2.4 Boundaries of the Femoral Canal

Clinical Features

• Classically, a lump felt inferolateral to the pubic tubercle.
• 40% present as emergencies due to the narrow neck–more likely to strangulate.
• Cough impulse is rarely detected for the same reason.

Differential Diagnosis

• Femoral canal lipoma
• Saphena varix (SFJ varices)
• Lympohadenopathy
• Femoral artery aneurysm
• Femoral artery pseudoaneurysm (post-angiography)
• Sarcoma (leio/rhabdomyosarcoma)

Management

• All femoral hernias should be surgically repaired (high risk of complication).

Figure 2.7 Umbilical hernia. Courtesy of Dr Jaclyn Croyle

Umbilical Hernia

Aetiology

• Female : Male 2:1
• Risk factors: Pregnancy, obesity.
• Up to 50% prevalence in screened patients.

Types of Umbilical Hernia

• True: Always congenital.
• Through umbilical cicatrix
• May close spontaneously by 3 years of age.
• Periumbilical
• Always acquired.
• Not through the umbilicus itself.
• Common in obese patients and multiparous women.

Management

• Most are asymptomatic and can be managed conservatively.
• True umbilical hernias should be surgically repaired after 3 years of age.

Incisional Hernia

Aetiology

• Up to 20% of laparotomy incisions eventually herniate in a lifetime
• Risk factors:
• Post-operative wound
• Infection
• Abdominal obesity
• Poor muscle quality (smoking, anaemia)
• Multiple operations through the same incision
• Poor choice of incision
• Inadequate closure technique

Clinical Presentation

• Lump and defect: Vary from small (more dangerous) to complete defects. May be asymptomatic but tend to progressively enlarge.
• Rarely cause strangulation.

Management

• Repair is usually indicated if symptomatic/strangulated.
• Mesh used for larger defects (>4 cm).

Spigelian Hernia

Key Points

• Defect between lateral border of the rectus abdominis and linea semilunaris.
• The hernial sac comes to lie between the layers of internal oblique, external oblique, and transversus abdominis.
• Hernial sac is found lateral to the rectus sheath, directly behind external oblique. Difficult to diagnose clinically.

Figure 2.8 Spigelian hernia.

Obturator Hernia

• Usually requires imaging (US/CT).
• Direct surgical repair is indicated.

Figure 2.9 Obturator hernia.

Key Points

• Defect through the obturator canal (lateral pelvis into thigh).
• Causes medial thigh pain in cutaneous distribution of the obturator nerve.
• Very challenging diagnosis–CT usually required.
• High risk of incarceration/obstruction.

Videos for further understanding

Click image to view video

Links

• Introduction to Groin Hernias: https://www.youtube.com/watch?v=nmD6nZdJtuU&t=30s
• Anatomy of the inguinal region: https://www.youtube.com/watch?v=JT8-dJyH0XI
• Femoral hernia: https://www.youtube.com/watch?v=HC59nyRKBEE&t=256s
• Spigelian Hernia: https://www.youtube.com/watch?v=RXeDhipaDeA
• Explaining Laparoscopic hernia repair: https://www.youtube.com/watch?v=x1TYXDDQZr4