Hernia is a protrusion of the viscus or internal organ through the defect, weakness or abnormal opening of the wall containing its cavity. Hernia is caused by an increase in the intra- abdominal pressure. Condition that may lead to an increase in the intra-abdominal pressure may include chronic cough, COPD sufferer, obese individual, pregnant women , patient with ascites, constipated patient who is straining and forced micturition in case of urinary retention. Appendectomy and poor wound factor may also contribute to hernia. Types of hernia may include inguinal hernia (direct inguinal and indirect inguinal hernia), femoral hernia, incisional hernia, Para umbilical hernia, umbilical hernia and epigastric hernia.
Anatomy of the inguinal canal
Inguinal canal runs from deep /internal inguinal ring to superficial /external inguinal ring. Deep/internal inguinal ring is anatomically located at the midpoint of inguinal ligament and superficial /external ring is anatomically located at the pubic tubercle.
Inguinal ligament runs from anterior superior iliac spine to the pubic tubercle. The pubic tubercle is 1.5 cm lateral to the position of the symphysis pubis. Mid- point of the inguinal ligament is the midpoint between the anterior superior iliac spines and the pubic tubercle. It is different from the mid inguinal point. The mid- inguinal point is the mid- point between the anterior superior iliac spines and the symphsis pubis. Mid- point of inguinal ligament is 1 finger breadth lateral to the mid –inguinal point. Femoral artery and femoral head located 2cm below the mid – inguinal point.
The entry and exit point of the inguinal canal is important for example for the testes to descend into the scrotum by the action of the gubernaculum. The testis itself is dragged by the spermatid cord.
Boundaries of inguinal canal include anterior wall, posterior wall, roof and floor of the inguinal canal. The anterior wall laterally consists of internal oblique muscle and most of the part consists of external oblique aponeurosis.
The posterior wall consists of medially the conjoint tendon and thoroughly covers by the transversalis fascia. What is a conjoint tendon? Conjoint tendon consists of lower edge of the transversus abdominus and external oblique muscle and fascia. The conjoint tendon is inserted into the pectineal line of the pubic bone and the pubic crest.
The floor of the inguinal canal is made up from the inguinal ligament that rolled in to it and reinforced by lacunar ligament medially. Spermatid cord (male) and round ligament(female) run in the inguinal canal. The spermatid cord consists of 3 layers of covering that develop during the descend of the testes. The layers consist of internal spermatid fascia, cremasteric fascia and external spermatid fascia. The internal spermatid fascia consists of transversalis fascia that present on the deep inguinal ring. The cremasteric fascia and muscle consists of trasnversus abdominus muscle and fascia as well as internal oblique fascia and muscle. The external spermatid fascia consists of external oblique aponuerosis.
Spermatid cord consists of arteries such as testicular artery from the aorta, cremasteric artery from the inferior epigastric artery and ductus vas deferns artery from the superior vesical artery. It also consists of sympathetic nerve, ilioguinal nerves and genital branch of the genitofemoral nerve. Besides that it also consists of hernia sac or patent processus vaginalis, venous pampiniform plexus (which is the venous drainage of the testicular), lymphatic system and ductus vas deferens.
Inguinal hernia usually contain small bowel. Inguinal hernia is divided into direct inguinal hernia and indirect inguinal hernia. Direct inguinal hernia occurs due to weakness of the conjoint tendon /medial wall of the posterior aspect of the inguinal canal. It is presented as a bulging of the medial aspect of the posterior wall of inguinal canal. The bowel doesn’t enter the inguinal canal. Direct inguinal hernia doesn’t cause any extension of the scrotum as the bowel doesn’t enter the inguinal canal unless the hernia is extremely large enough .Direct inguinal hernia cannot be controlled after reduction or applying a digital pressure on the deep ring to reduce it. In performing surgery, direct inguinal hernia is located within the Hasselbach’s triangle. The triangle consists of inferior epigastric artery laterally, conjoint tendon medially and inguinal ligament inferiorly. Surgical procedure such as appendectomy may lead to direct inguinal hernia due to division of the ilioinguinal nerve.
Indirect inguinal hernia is caused by weakness at the deep ring of the inguinal canal. The bowel enters the inguinal canal through the deep ring and travel through the inguinal canal within the patent processus vaginalis/hernia sac. Scrotal extension or inguinoscrotal hernia is possible as the bowel leaves the superficial ring to enter the scrotum. The bowel that is herniated can be controlled after applying a digital pressure on the deep ring /midpoint of the inguinal ligament. The bowel also can be controlled after reduction. In surgery, indirect inguinal hernia is identified by the position of the hernia which is lateral to the inferior epigastric hernia.
The direct and indirect inguinal hernia examination may begin in standing and supine position which depends on the patient’s position. The inspection may include, look for any evidence of scrotal bulge, scrotal extension, colour changes, scar from previous surgery and contralateral present of the hernia. Palpation may include to feel for any tenderness, temperature, reducibility of the hernia (better to ask patient to do it), expansile cough impulse and palpate the end of the scrotal mass. Ability to feel the spermatid cord above the mass may exclude the present of hernia. The hernia is also auscultated for the present of any bowel sound.
The differential diagnosis of inguinal hernia may include lipoma on the skin or subcutaneous
tissue, undescended testes, lipoma of the cord, vaginal hydrocele which is continuous with the peritoneum and femoral hernia.
Incarcerated hernia is the form of hernia which is caused by adhesion around the sac. It is irreducible but incarcerated hernia is non-occlusive. Small bowel /mechanical obstruction put the risk of developing incarcerated hernia. The constriction of the hernia neck is a predisposing factor of developing incarcerated hernia. Strangulated hernia is a hernia which consists of ischemic bowel. Strangulated is an irreducible, tense and tender hernia that present with absent of the bowel sound. Reduction en mass is the term used to describe the whole reduction of the hernia sac which includes the constricting hernia neck and strangulated bowel. Reduction en mass carries an increased risk of generalized peritonitis and abdominal perforation.
Other variants of inguinal hernia may include maydl’s hernia, pantaloon hernia and Ritcher’s hernia. Maydl’s hernia is also known as double loop hernia or en W shape hernia because of the shape of the hernia. In maydl’s hernia the distal as well as the proximal part of the central infolded loop of bowel became incarcerated while the cneter infolding loop of bowel is at high risk of strangulation.
Pantaloon hernia is the type of hernia that present as a shape of the legs of the pair of trousers. In pantaloon hernia both the direct and indirect inguinal hernia present and straddling the inferior epigastric artery during the operation.
Littre’s hernia is a hernia which consists of meckel diverticulum while amyand’s hernia is a hernia where the hernia sac consists of inflamed appendix. Hernia sac which is made up from viscus such as bladder or caecum is known as sliding hernia. Richter’s hernia is a hernia that consists of knuckle of bowel. The knuckle of bowel is originated form the border of the anti-messenteric . The knuckle of bowel is constricted at the hernia sac. The constriction doesn’t cause any complete obstruction of the intestinal lumen. Ritcher’s hernia is also known as partial enterocele hernia, levator hernia and nipped hernia.
The treatment option for inguinal hernia may include conservative and surgical approach. The conservative approaches involved the use of truss. Truss is a specialized belt that applies pressure to the hernia defect with the aims to control the hernia. It is only used in elderly patient who is unfit for anaesthetic. However the result is unsatisfactory.
Surgical approaches may include laparoscopic herniorrhapy or open herniorrhapy . The surgery is done electively in cases which are uncomplicated. It may also be performed in emergency situation, where strangulation and obstruction may present. Open herniorrhapy may include shuldice repair and mesh/Lichtenstein repair. In shouldice repair the bowel is reduced, the deep ring is tightened and the posterior walls of the inguinal canal is split, overlap and finally sutures with prolene suture. Mash or Lichtenstein repair follow the same principle as the Shouldice repair but the posterior wall is not split and the prolene mesh is applied to improve the integrity of the posterior wall of the inguinal canal.
lichenstein repair for inguinal hernia
Mesh repair for inguinal hernia
Femoral canal is made up from anterior, posterior, medial and lateral border. The anterior border consists of inguinal ligament, the posterior border consists of pectineal ligament (Gimbernats) and the medial sides consist of lacunar ligament. Lateral part of the femoral canal consists of inferior vena cava. Femoral canal contains deep inguinal node of cloquet that drain the penis and clitoris lymph as well as fatty connective tissue.
Femoral hernia is more common in female (2.5:1) to male. However the inguinal hernia is still the commonest in women. The femoral hernia may contain omentum but in some cases may contain small bowel. The differential diagnosis of femoral hernia may include lipoma of the skin and subcutaneous tissue, ectopic testes, enlargement of the deep inguinal node of cloquet and saphena varix or varicosities of the saphenous vein.
The femoral hernia is different from the inguinal hernia because femoral hernia located below and laterals to the pubic tubercle while the inguinal hernia is located above and medial to the pubic tubercle. Surgery should be done urgently due to increases risk of ischemia as the 3 sides of the femoral canal is a rigid structures which doesn’t allowed any expansion.
Surgical option may include high operation/inguinal operation, low operation, crucal operation, extraperitoneal , andominal and suprapubic operation. The patient who suffers from bilateral hernia, obstruction, strangulation and previous history of groin surgery may require suprapubic /extraperitoneal/abdominal surgical approach. High operation/inguinal operation are performed when concomitant inguinal hernia is present which simultaneously can be repaired. Low operation/crural operation are considered in uncomplicated cases of femoral hernia in female who is lean. This operation is performed in elective cases.
Other variants of hernia
Other form of hernias may include incisional hernia. Incisional hernia is a type of hernia that is associated with poor wound healing. The major factor that determine the development of the incisional hernia may include, immunosuppression, obesity, age, malnutrition, foreign body( stoma/drain), poor wound healing, poor wound closing technique, infection and hematoma. Longitudinal incision has a high degree of developing incisional hernia while pfannensteil incision is the least common.
Gluteal hernia is the type of hernia that herniated through the pelvis greater sciatic notch. Lumbar hernia is the type of hernia which herniated through the obturator canal of the pelvis. Lumbar hernia is more common in female than male. Lumbar hernia is associated with a variation of the Richter’s hernia. The boundaries of lumbar hernia may include anterior latissimus dorsi, iliac crest and posterior external oblique. Spigelian hernia is a form of hernia which herniated through the lateral edges of the fascia (also known as linea semilunaris ) enclosing the rectus abdominus.
Umbilical hernia is a form of hernia which affects 3% of life birth, 3:1000may need to be repaired, and the repair is done at the age of 3 and may recur during pregnancy especially at the 3rd trimester. Afro Caribbeans are more prone in developing umbilical hernia. Umbilical hernia usually contains omentum.
Umbilical hernia is different from the paraumbilical hernia. Paraumbilical hernia usually occurs through a defect which is located lateral to /adjacent to the actual umbilical cicatrix/scar. Umbilical hernia is a hernia which is herniated through the scar/ weakness of the actual umbilical cicatrix.
Umbilical hernia is repaired surgically using a mesh repair or a mayo repair. A mesh repair involved the excision of the hernia sac and reduction of the hernia as well as the use of prolene mesh to close the defect. In mayo repair the edges that had been cut are overlapped and sutured with prolene suture.
Epigastric hernia is a form of hernia that is presented as swelling in the epigastrium region. Patient with epigastric hernia may suffer from the feeling of discomfort but they may rarely complain of any pain. Epigastric hernia is often mistaken with lipoma and epigastric hernia usually contains omentum. Epigastric hernia is treated in a similar fashion as umbilical hernia ( mayo repair or mesh repair ).
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