Notes on hernias for medical finals in surgery

1. Hernia Revision
Christiane Riedinger September 2014

2. TOC

3. Definitions
● Hernia A condition in which part of an organ is displaced and
protrudes through the wall of the cavity containing it (often involving
the intestine at a weak point in the abdominal wall).
Clinical definition:
A (non)reducible lump with a cough impulse and bowel sounds.
● Abd. hernia The protrusion of a viscus or part of a viscus through the
walls of its containing cavity into an abnormal position.
● Neck The margin of the defect through which the hernia protrudes
● Sliding herniaA hernia of a structure that is partially extraperitoneal, so that
The hernial sac does not completely surround the entire
hernia.
● Irreducible h. May be incarcerated, i.e. irreducible due to adhesions within
the sac, eventually the bowel within may become obstructed.

4. Definitions (2)
● Strangulation Blood supply to the hernia is impaired, first the venous,
then the arterial which causes swelling and pain and
eventually obstruction and gangrene. => surgical
emergency
● Indirect ing.h. Bowel passes through the inguinal canal from the deep
ring to the superficial ring, starting lat. to the inf. epig. a.
● Direct ing. h. Bowel passes through a defect in the abdominal wall
medial to the inferior epigastric vessels.
● Richter’s hernia Only part of the bowel circumference protrudes,
therefore no obstruction, but strangulation!

5. Types of Hernias
● Congenital types Indirect inguinal and umbilical hernias
● C. inguinal h. Patent processus vaginalis resulting in an indirect
inguinal hernia
● C. umbilical h. Often recur spontaneously, surgical repair if >1cm or at
3-4y
● Omphalocoele Developmental abdominal wall defect resulting in the
protrusion of abdominal organs within the peritoneal sac from which
the umbilical cord emerges. Associated with other congenital
abnormalities.
● Gastroschisis Developmental abdominal wall defect resulting in the
protrusion of bowel without peritoneal covering, usually at the R
junction of the umbilicus and the skin. It is less associated with
other abnormalities than the omphalocoele
● Incisional hernia Often managed conservatively with abdominal elastic support
corset or mesh repair.

6. Types of Hernias (2)
● Acquired types Inguinal, femoral, umbilical (more precise: paraumbilical)
● A. indirect ing. h. Viscus exits superomedial to pubic tubercle at superficial ring.
● A. direct ing.h. Viscus emerges medial to the inf. epigastric a. and deep ring, but can
also pass along inguinal canal
● Femoral hernia Viscus passing through the femoral canal, inferolateral to the pubic
tubercle. More common in females and at higher risk of strangulation due to
the sharp edges of the lacunar ligament. It should always be repaired surgically
(herniotomy and herniorrhaphy)
● Epigastric hernia Midline through linea alba
● Spigelian hernia Hernia into post. rectus sheath below arcuate line. Lump near semilunar line.
● Obturator hernia Through obturator foramen, causing pain in obturator nerve (inner
thigh) +/- obstruction. Typical case: old thin lady.
● The key is to reduce the hernia and see where it emerges from! Superomedially to pubic tubercle =
inguinal, inferolaterally = femoral. You can also reduce the hernia and cover the deep inguinal ring,
then ask the patient to cough. If pressure on the deep ring controls the hernia, then it is an indirect
hernia. Final confirmation at OP!

7. Predisposing Factors for abd. Hernias
● Chronic cough
● Chronic constipation
● Prostatism leading to straining to pass urine
● Heavy manual labour including lifting
● Obesity
● Weakening of abdominal wall muscles
● Age
● Previous abdominal surgery
● Post-operative wound infection or haematoma, poor surgical technique
● Multiple pregnancies
● Patent processus vaginalis
● Cirrhosis, ascites

8. Important Surface Anatomy
● Midpoint of the inguinal ligament
○ ½ between ASIS and pubic tubercle
○ Location of deep inguinal ring is at mid-point of the inguinal ligament or ~1.5cm
above the midpoint of the inguinal ligament (surgical book)
○ Direct hernia will be MEDIAL to this! An indirect inguinal hernia emerges lateral to
the inferior epigastric artery and then passes medially along the inguinal canal.
● Mid-inguinal point
○ ½ between ASIS and pubic symphysis
○ FEMORAL ARTERY
○ This is medial and superior to the midpoint of the inguinal ligament

9. Anatomy of the Inguinal Canal
● Inguinal ligament passes from the ASIS to the pubic tubercle. It is formed by the rolled-in lower border of
external oblique.
● The inguinal canal is 4-5cm long and lies ABOVE (i.e. caudal?) the medial half of the inguinal ligament. It
contains the vas deferens, its artery and testicular vessels and the ilioinguinal nerve in males, the round
ligament in females.
● Floor of inguinal canal (caudal side): external oblique forming the inguinal ligament and the lacunar ligament
medially
● Roof of the inguinal canal (cranial side): internal oblique and conjoint tendon medially
● Posterior wall of the inguinal canal is the transversalis fascia and the conjoint tendon medially.
● The anterior wall of the inguinal canal is the external oblique aponeurosis reinforced laterally by the inferior
oblique.
● Lacunar ligament goes from inguinal ligament to the pectineal line (inferiorly to the inguinal ligament).
● The ilioinguinal nerve runs in the same direction as the canal and enters it from in-between inferior and
external oblique muscles on the lateral side.
● The deep ring is an opening in the transversalis fascia superior to the midpoint of the inguinal ligament.
● The superficial ring is a triangular opening in the external oblique aponeurosis protected posteriorly by the
conjoint tendon.

10. Anatomy of the Abdominal Wall
● OUTMOST MUSCLE: External oblique (lower 8th ribs to iliac crest, pubic tubercle and linea alba,
runs DOWNWARDS AND FORWARDS not lower than level of ASIS and umbilicus) becomes
aponeurotic from ASIS medially and inferiorly as inguinal ligament with its lower border in-rolled.
● MIDDLE MUSCLE: Internal oblique (lumbar fascia, lat ⅔ of inguinal ligament and iliac crest to linea
alba and conjoint tendon to pectineal line at the superior ramus of the pubic bone, runs UPWARDS
AT 90* to external oblique, create rectus sheath above the arcuate line). AT SAME LEVEL AS
RECTUS IN TERMS OF DEPTH
● INNERMOST MUSCLE: Transverse abdominus (lumbar fascia, iliac crest, inguinal ligament and
costal cartilages to xiphoid process, linea alba, pubic crest and conjoint tendon to pectineal line, runs
TOWARDS THE MIDLINE.
● The rectus muscle goes from the pubic symphysis to the xiphisternum and is ensheathed by the
aponeuroses of the abdominal muscles: The external oblique aponeurosis passes superiorly, the
internal oblique encloses the muscle superiorly and inferiorly, the transverse abdominus muscle
aponeurosis passes inferiorly up to the arcuate line (inf.) below which the rectus lies on the
transversalis fascia only.

11. Anatomy of the Femoral Canal
● Mid-inguinal point
○ ½ between ASIS and pubic symphysis
○ FEMORAL ARTERY
● The femoral triangle is a subfascial space of the upper thigh bordered laterally by the sartorius
muscle, medially by the adductor longus muscle and superiorly by the inguinal ligament, which
continues as the sharp-edged lacunar ligament medially. It contains the femoral nerve laterally, the
femoral artery and femoral vein more medially, as well as the femoral canal, which contains lymph
nodes and fat and passes lymphatics from superficial to deep. The femoral artery, vein and canal are
embedded within the femoral sheath in three compartments. The femoral sheath is a tunnel-like
continuation of the fasciae lining the abdomen.
● A weakness in the femoral canal can result in viscus passing through where it is at particular risk of
strangulation due to the sharp edges of the lacunar ligament.
● Femoral hernias are present lateral and inferior to the pubic tubercle, inferior to the inguinal ligament
and medial to the femoral vein.

12. Surgical Procedures
● Herniotomy Ligation and excision of the hernial sac, if femoral hernia
then ligation of inguinal ligament and pectineal ligament
● Herniorrhaphy Repair of the hernial defect, e.g. post. wall of inguinal
canal and deep inguinal ring with a nylon mesh, lowering
the risk of recurrence compared to sutures.
● Laparoscopic repair of inguinal hernias is associated with reduced pain
and numbness.