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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

Classification According to Anatomical Location		Classification According to Aetiology
Ventral	Umbilical/periumbilical, parastomal, epigastric, spigelian	Congenital	Defect is present from birth (+perinatal repair) Persistent processus vaginalis– risk of indirect inguinal hernia Gastroschisis–risk of periumbilical hernia Omphalocoele–risk of umbilical hernia
Groin	Inguinal, femoral, pantaloon	Acquired– primary	Increased abdominal pressure or weakened abdominal wall Risk factors: Ageing, smoking, steroid use, pregnancy, obesity, chronic cough, connective tissue disorders, heavy lifting
Pelvic	Obturator, sciatic, perineal	Acquired– primary
Flank	Superior/inferior lumbar triangle hernias	Acquired– incisional (secondary)	Iatrogenic wall damage Post-surgical–surgical site infection increases risk

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The Triangles In Hernia Anatomy Are Crucial Landmarks That Guide Surgeons In Distinguishing Hernia Types And Avoiding Injury To Vessels And Nerves During Repair. Their Boundaries Highlight Areas Where Hernias Occur And Where Careful Dissection Is Needed To Prevent Complications, Especially To Avoid Vessels Andor Nerves.

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.

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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

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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

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Inguinal Hernia Can Be Indirect–Passes In the Inguinal Canal (Through Deep Inguinal Ring And Emerges Through the Superficial Ring), Or Direct–Protrudes Through the Transversalis Fascia

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A Direct Inguinal Hernia Occurs Medially To the Inferior Epigastric Vessel, While An Indirect Inguinal Hernia Occurs Laterally To the Inferior Epigastric Vessels

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).

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Figure 2.3 Inguinal canal.

Table 2.2 Contents of the Inguinal Canal

Three Vessels

Testicular artery and vein (pampiniform venous plexus)
Artery and vein to the vas deferens
Cremasteric artery and vein

Four Nerves

Nerve to the cremaster
Sympathetic nerves
Ilioinguinal nerve
Genital branch (genitofemoral nerve)

Three Fasciae

External spermatic fascia
Cremasteric muscle and fascia
Internal spermatic fascia

Three Others

Spermatic cord
Vas deferens
Lymphatics

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.

A diagram of the femoral triangle

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Figure 2.6. Boundaries of the femoral triangle

Surgical Anatomy

Table 2.3 Boundaries of the Femoral Triangle

Superior	Inguinal ligament
Lateral	Medial border of sartorius muscle
Medial	Medial border of adductor longus
Floor	Iliacus, psoas major, pectineus, adductor longus
Roof	Superficial fascia and great saphenous vein
Contents of the Femoral Triangle
From medial to lateral	Canal, vein artery, nerve (CVAN)

Table 2.4 Boundaries of the Femoral Canal

Anterior	Inguinal ligament
Lateral	Femoral vein
Medial	Lacunar ligament
Posterior	Pectineal ligament
Contents of the Femoral Canal
Lymphatics (Cloquet’s node) and fat

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).

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If a patient has saphena varix, ask them to lie flat and it should disappear; you should feel a thrill on coughing. the patient will likely have varicose veins elsewhere.

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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.

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Figure 2.8 Spigelian hernia.

Obturator Hernia

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

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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

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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