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Hernia - Complete Surgery Posting Notes
Sources: Schwartz's Principles of Surgery 11e, Maingot's Abdominal Operations, Bailey & Love's Short Practice of Surgery 28e, Current Surgical Therapy 14e, Fischer's Mastery of Surgery 8e
Definition
A hernia is an area of weakness or complete disruption of the fibromuscular tissues of the body wall through which structures from the contained cavity herniate. The hernia refers to the actual anatomic defect; hernia contents are the structures that pass through it. - Maingot's Abdominal Operations
Epidemiology
- Inguinal hernia repair is the most common general surgery procedure performed worldwide
- ~700,000 inguinal hernia repairs/year in the US; an additional 450,000 in ambulatory surgery centers
- ~75% of abdominal wall hernias occur in the groin
- 90% of inguinal hernia repairs are in men, 10% in women
- Lifetime risk: men 27%, women 3%
- Bimodal age distribution: peak before 1 year and after 40 years
- Inguinal > Femoral (5:1)
- ~70% of femoral hernia repairs are in women, but the most common groin hernia in both sexes is still indirect inguinal
- Incisional hernias develop in up to 28% of patients after laparotomy - Current Surgical Therapy 14e
Anatomy of the Inguinal Canal
Digital examination of the inguinal canal (Schwartz's Principles of Surgery)
The inguinal canal is an approximately 4-6 cm long cone-shaped region in the anterior pelvis. - Schwartz's Principles of Surgery 11e
| Boundary | Structure |
|---|
| Anterior | External oblique aponeurosis |
| Posterior | Transversalis fascia + transversus abdominis |
| Superior | Internal oblique + transversus abdominis |
| Inferior | Inguinal (Poupart's) ligament |
| Deep ring | Hiatus in transversalis fascia |
| Superficial ring | Defect in external oblique aponeurosis |
Key Structures
- Iliopubic tract: aponeurotic band from ASIS to Cooper's ligament; forms inferior margin of internal ring
- Cooper's ligament (pectineal ligament): on the superior surface of the pubic ramus; critical for McVay repair
- Lacunar ligament (Gimbernat's): triangular fanning of the inguinal ligament at the pubic tubercle; forms the medial boundary of the femoral canal
- Conjoined tendon: fusion of internal oblique and transversus abdominis aponeuroses; inserts on pubic tubercle
- Hesselbach's triangle: bounded by inferior epigastric vessels laterally, inguinal ligament inferiorly, rectus sheath medially - site of direct hernias
Spermatic cord contents (3-3-2 rule)
- 3 arteries: testicular, cremasteric, artery of vas deferens
- 3 veins: pampiniform plexus, cremasteric vein, vein of vas
- 2 nerves: ilioinguinal nerve, genital branch of genitofemoral nerve
- Vas deferens
Classification
By Etiology
- Congenital (indirect inguinal) - patent processus vaginalis
- Acquired (direct inguinal, incisional, femoral)
By Clinical State
| Type | Description |
|---|
| Reducible | Contents return spontaneously or with gentle pressure |
| Irreducible (Incarcerated) | Contents cannot be reduced; no vascular compromise |
| Obstructed | Bowel in sac with intestinal obstruction, no strangulation |
| Strangulated | Vascular compromise of contents; surgical emergency |
| Richter's hernia | Only the antimesenteric wall of bowel is strangulated - can strangulate without obstruction |
| Maydl's hernia (hernia-en-W) | Two loops in sac, middle loop strangulates inside abdomen |
| Littre's hernia | Meckel's diverticulum in the sac |
| Sliding hernia | Posterior wall of sac formed by a viscus (cecum on right, sigmoid on left) |
| Pantaloon hernia | Combined direct + indirect hernia straddling inferior epigastric vessels |
Nyhus Classification (most widely used grading for inguinal hernias)
| Type | Description |
|---|
| I | Indirect, normal internal ring |
| IIA | Direct, small |
| IIB | Direct, large |
| IIIA | Direct |
| IIIB | Indirect, enlarged ring ± sliding or scrotal |
| IIIC | Femoral |
| IV | Recurrent |
Types of Groin Hernia
Indirect Inguinal Hernia
- Passes through the deep (internal) inguinal ring, traverses the canal, exits the superficial ring
- Lateral to the inferior epigastric vessels
- Congenital: due to patent processus vaginalis
- Most common type in both sexes and all ages
- Sac can reach the scrotum (scrotal hernia)
Varying degrees of closure of the processus vaginalis: A. Closed. B. Minimally patent. C. Moderately patent. D. Scrotal hernia. (Schwartz's Principles of Surgery)
Direct Inguinal Hernia
- Protrudes directly through the posterior wall of Hesselbach's triangle
- Medial to the inferior epigastric vessels
- Acquired; due to weakness in transversalis fascia
- Less likely to strangulate (wide neck)
- Common in older men
Differentiating Direct vs Indirect - Key Points
| Feature | Indirect | Direct |
|---|
| Relation to inf. epigastric | Lateral | Medial |
| Mechanism | Through deep ring | Through Hesselbach's triangle |
| Age | Any (often young) | Older |
| Strangulation risk | Higher | Lower |
| Cough impulse on digital exam | Tip of finger | Dorsum of finger |
| Control on deep ring pressure | Controlled | Not controlled |
Note: Clinical accuracy of differentiating direct from indirect hernia is only slightly better than chance (50%); confirmation is operative. - Schwartz's Principles of Surgery 11e
Femoral Hernia
- Passes through the femoral canal (medial to femoral vein, lateral to lacunar ligament), below the inguinal ligament
- F:M ratio ~3:1 overall; but indirect inguinal is still most common groin hernia in women
- High risk of strangulation due to tight unyielding femoral ring
- Presents as a lump below and lateral to the pubic tubercle (distinguished from inguinal hernia which is above and medial)
- Often presents as an emergency with strangulation
Risk Factors for Hernia
Conditions that raise intra-abdominal pressure
- Chronic cough (COPD)
- Constipation / straining
- Prostatic hypertrophy
- Ascites
- Obesity
- Pregnancy
Connective tissue disorders (Schwartz's)
Marfan syndrome, Ehlers-Danlos, osteogenesis imperfecta, alpha-1 antitrypsin deficiency, polycystic kidney disease, androgen insensitivity syndrome
Other
- Previous surgery (incisional hernia)
- Smoking (collagen defect)
- Family history (hereditary in 3-fold if first-degree relative affected)
- Male sex
Diagnosis
Clinical
- Groin mass that protrudes on standing, coughing, or straining
- May have dragging/aching pain, especially at end of day
- Reducible on lying down
Physical Examination
- Patient examined standing and lying
- Cough impulse test; digital invagination of scrotal skin along the inguinal canal
- Tip of finger impulse = indirect; Dorsum of finger impulse = direct
- For femoral: palpate below the inguinal ligament, lateral to pubic tubercle
- Assess reducibility; if not reducible, assess for strangulation (tenderness, erythema, systemic signs)
Differential Diagnosis of Groin Swelling
Lymph node, lipoma of cord, undescended testis, saphenous varix, femoral artery aneurysm, psoas abscess, hydrocele, sebaceous cyst, hematoma
Imaging
- Not required for obvious hernias
- Ultrasound: sensitivity 86%, specificity 77% for inguinal hernia; first-line imaging
- CT scan: delineates anatomy, detects occult hernias, excludes other pathology
- MRI: best soft tissue differentiation; used for occult/sports hernia
Management
Conservative
- Watchful waiting is acceptable for asymptomatic or minimally symptomatic reducible inguinal hernias in men
- Risk of strangulation: ~0.5-1% per year; decreases from ~5%/year to 1-2%/year after 6 months as defect enlarges
- Watchful waiting is not safe for femoral hernias (high strangulation risk - all should be repaired)
- Trusses: temporary measure only; no evidence of benefit; may worsen matters by preventing natural reduction
Indications for Surgery
- Symptomatic hernia
- Irreducible hernia
- All femoral hernias
- Any complication (obstruction, strangulation)
- Pediatric hernias (repair promptly to avoid incarceration)
- Patient preference
Anesthesia Options (Maingot's)
| Type | Notes |
|---|
| Local (preferred for open) | Ilioinguinal + iliohypogastric nerve block or direct infiltration; least postoperative pain/nausea, shortest recovery; superior in RCT vs regional or GA |
| Regional (spinal/epidural) | Larger operative field; risks: urinary retention, hypotension, prolonged effect |
| General | Required for laparoscopic; complete muscle relaxation needed for insufflation |
Surgical Repair Techniques
Principle: Tension-free repair - the gold standard
Simple suture repair (without mesh) has recurrence rates up to 15%. Mesh repair dramatically reduces recurrence rates.
A. OPEN ANTERIOR REPAIRS
1. Lichtenstein Tension-Free Mesh Repair (Gold Standard for Open)
- Described by Lichtenstein in the 1980s
- A flat synthetic mesh (typically polypropylene) is placed as an onlay on the posterior wall of the inguinal canal
- Keyhole in the mesh accommodates the spermatic cord
- Mesh is sutured to the inguinal ligament inferiorly and conjoined tendon superiorly
- Recurrence rate <1% in experienced hands
- Short learning curve; reproducible regardless of hernia size
- Used for direct, indirect, and combined hernias
2. Tissue-Based (Non-Mesh) Repairs
| Repair | Technique | Notes |
|---|
| Bassini (1884) | Sutures transversalis fascia + internal oblique + transversus abdominis ("triple layer") to inguinal ligament | Revolutionized hernia repair; recurrence ~5-10% |
| Shouldice | Four-layer imbrication of transversalis fascia with running monofilament | Best tissue repair; recurrence ~2-4% at specialist centers; technique-dependent |
| McVay (Cooper's ligament) | Sutures transversalis fascia/conjoined tendon to Cooper's (pectineal) ligament; requires a relaxing incision | Only repair that addresses both inguinal AND femoral defects; used for femoral hernia, large direct hernia |
| Desarda | Uses a strip of external oblique aponeurosis | Newer modification; being evaluated |
The Cooper's ligament repair (McVay) is the only technique that definitively repairs both the inguinal and femoral hernia defects. - Maingot's Abdominal Operations
3. Plug and Patch (Rutkow-Robbins)
- A mesh plug fills the hernia defect + flat mesh reinforces the floor
- Concern about plug migration and chronic pain; less used now
B. LAPAROSCOPIC REPAIRS
The key anatomical difference: laparoscopic approaches repair the hernia posterior to the defect (preperitoneal plane), whereas open approaches repair it anteriorly. - Maingot's Abdominal Operations
Three techniques exist:
1. TAPP - Transabdominal Preperitoneal
- Standard laparoscopy enters the peritoneal cavity
- Peritoneum over the groin is incised and dissected off
- Mesh placed in the preperitoneal space; peritoneum closed over it
- Good visualization; allows concurrent contralateral assessment
- Risk of intraperitoneal injury
2. TEP - Totally Extraperitoneal
- Balloon dissection creates preperitoneal space without entering peritoneum
- Mesh placed directly in preperitoneal space
- Avoids peritoneal entry; less risk of bowel/vessel injury
- Longer learning curve; difficult with previous lower abdominal surgery
- Preferred by many for unilateral primary hernia
3. IPOM - Intraperitoneal Onlay Mesh
- Mesh placed intraperitoneally
- Requires composite/dual-layer mesh to avoid adhesion to bowel
- Less commonly used for inguinal hernia; more for ventral hernias
Laparoscopic vs Open (Key Points)
- Laparoscopic: less postoperative pain, faster return to activity, lower chronic pain rates
- Laparoscopic: longer learning curve (especially TEP), requires GA
- Laparoscopic: preferred for bilateral hernias (both sides repaired through same incisions) and recurrent hernias after open anterior repair
- Open Lichtenstein: preferred for recurrent hernias after laparoscopic repair, heavily scarred preperitoneal space, patients unfit for GA
- Recurrence rates equivalent between laparoscopic and open with mesh
Robotic Repair
- Robotic inguinal hernia repair has grown rapidly: from 0.7% to 28.8% of inguinal repairs (2012-2018, Michigan Surgical Quality Collaborative)
- Provides better ergonomics and 3D visualization
- Similar outcomes to standard laparoscopic; higher cost - Sabiston Textbook of Surgery
C. MESH MATERIALS
Synthetic Mesh
- Polypropylene (most common) and polyester
- Permanent, hydrophobic; induce local inflammatory response leading to fibrosis and incorporation
- Heavyweight: stronger but more scarring, higher chronic pain risk
- Lightweight (titanium-coated PP, PP-poliglecaprone): more elasticity, less surface area contact
- Meta-analysis of 2310 patients: lower chronic pain (RR 0.61) with lightweight; no difference in recurrence
- Lightweight mesh recommended for TEP/TAPP repairs
Biologic Mesh
- Derived from human/animal connective tissue (acellular dermis, porcine SIS, etc.)
- Reserved for contaminated fields or patients with high infection risk
- High cost + high recurrence rates; no single biologic is standard
- Cross-linked grafts more durable than non-cross-linked
Important note from resource-limited settings
- Sterilized polypropylene mosquito nets have similar mechanical properties to commercial mesh
- Meta-analysis of 577 hernioplasties: similar short-term complication (6.1%) and recurrence (0.17%) rates
Special Hernia Types
Umbilical Hernia
- Common in neonates (90% close spontaneously by 3-4 years)
- In adults: acquired, associated with obesity, ascites, multiparity
- Repair indicated if persistent after age 4 in children; symptomatic or enlarging in adults
- Cirrhotic patients: high risk (up to 20% incidence with ascites); 15% mortality with urgent repair; optimized elective repair preferred
Incisional (Ventral) Hernia
- Occurs in up to 28% after laparotomy
- Risk factors: obesity (BMI >40 = 50% recurrence), smoking, diabetes (HbA1c >8), COPD, wound infection
- Watchful waiting acceptable for asymptomatic small hernias; ~10-15% will eventually require repair
- Repair: open (sublay/retrorectus mesh) vs laparoscopic IPOM
- Surgeon volume matters: >40 cases/year associated with 30-40% lower reoperation rate
Epigastric Hernia
- Through the linea alba above the umbilicus
- Often contains preperitoneal fat; symptomatic despite small size
- Simple repair with mesh for larger defects
Spigelian Hernia
- Through the spigelian fascia (lateral border of rectus abdominis, at the arcuate line)
- Interparietal hernia - lies between muscle layers; can be missed on exam
- Ultrasound/CT often required for diagnosis; laparoscopic repair preferred
Obturator Hernia
- Through obturator foramen; rare; most common in thin elderly women
- Presents with bowel obstruction + Howship-Romberg sign (inner thigh pain on hip extension/internal rotation due to obturator nerve compression)
- Usually diagnosed at emergency laparotomy for bowel obstruction
Hiatal Hernia
- Type I (Sliding): GE junction slides into the chest; 95% of all hiatal hernias; associated with GERD
- Type II (Paraesophageal/Rolling): GE junction below diaphragm, fundus herniates alongside
- Type III (Mixed): elements of both
- Type IV: other viscera (colon, spleen) in the sac
Internal Hernia
- Through a mesenteric or peritoneal defect; congenital or post-surgical (Roux-en-Y gastric bypass most common cause now)
- Presents with intermittent bowel obstruction; CT diagnosis; laparoscopic repair if caught early
Complications of Hernia
Acute Complications
| Complication | Features | Management |
|---|
| Incarceration | Irreducible, no vascular compromise; may have obstruction | Emergency surgery if cannot reduce; attempt gentle reduction (taxis) |
| Strangulation | Vascular compromise; tender, erythematous, systemic sepsis | Emergency surgery - no attempt at reduction; resection if bowel non-viable |
| Obstruction | Bowel obstruction without strangulation | Urgent surgery |
Signs of strangulation: local tenderness, erythema, edema of overlying skin, pyrexia, tachycardia, leukocytosis, metabolic acidosis
The larger the palpable defect, the lower the risk of incarceration. Risk is highest in the first few months (5%/year), drops to 1-2%/year after 6 months as the defect enlarges. - Maingot's Abdominal Operations
Post-operative Complications
| Complication | Notes |
|---|
| Urinary retention | Common especially after spinal anesthesia or in elderly men with BPH |
| Wound infection | 1-2% with mesh; higher with contaminated cases |
| Hematoma/seroma | Seroma common after laparoscopic TEP; usually resolves |
| Chronic groin pain (CPIIP) | Most important long-term complication; ~10-12%; due to mesh, nerve entrapment |
| Recurrence | <1% with Lichtenstein; 0.5-2% with laparoscopic; increases with infection, poor technique |
| Mesh infection | Rare (1%); may require mesh removal |
| Vas deferens/testicular injury | Risk of ischemic orchitis 0.5-1%; testicular atrophy rare |
| Nerve injury | Ilioinguinal, iliohypogastric, genitofemoral nerves at risk; numbness/neuralgia |
Pediatric Hernias
- Almost all are indirect (due to patent processus vaginalis)
- ~90% of boys with undescended testis have a patent processus vaginalis
- Hernias in children should be repaired promptly - incarceration risk is high in infants
- Herniotomy (high ligation of sac at internal ring) is sufficient - no floor repair needed in children
- Laparoscopic approach allows inspection of the contralateral side; contralateral repair if patent
Key Surgical Principles (Summary)
- Tension-free repair is the standard - mesh reduces recurrence
- Laparoscopic preferred for bilateral inguinal hernias and recurrent (after open) hernias
- Open Lichtenstein preferred for recurrent (after laparoscopic) hernias and patients unfit for GA
- All femoral hernias should be repaired regardless of symptoms
- Lightweight mesh preferred for laparoscopic repairs - less chronic pain
- Local anesthesia superior in RCT for open inguinal hernia repair
- Watchful waiting is safe for asymptomatic male inguinal hernias; not safe for femoral hernias
- Strangulation = emergency surgery; do not attempt reduction if signs of vascular compromise
- Preoperative optimization: smoking cessation, HbA1c <7%, BMI reduction improve outcomes for ventral hernia
- Cooper's ligament (McVay) repair is the only tissue repair that addresses both inguinal and femoral defects simultaneously
Sources: Schwartz's Principles of Surgery 11e (Chapter 37) | Maingot's Abdominal Operations (Chapter 7) | Bailey & Love's Short Practice of Surgery 28e | Current Surgical Therapy 14e | Fischer's Mastery of Surgery 8e | Mulholland & Greenfield's Surgery 7e