Inguinal Hernias Case: Mr. Strain, a 45-year-old man, who while trying to show his wife how strong he was, strained to pick up a particularly heavy coffee table. He suddenly felt a sharp pain in his right groin. Later, he noticed that a painful bulge had developed in his groin which disappeared when he was on his back. After several months, the pain and the bulge in his groin increased and he finally agreed to see a physician.
On exam, you observe a swelling which begins about midway between the anterior superior iliac spine and the midline, progresses medially for about 4 cm, and then turns toward the scrotum. Definitions Hernia: Protrusion of any viscus from its normal cavity through an abnormal opening. Hernias may be described as: Reducible Contents easily put back Irreducible Contents cannot be put back Strangulated Contents are stuck, and there is constriction of the tissues at the neck of the hernia, leading to reduced venous drainage and arterial occlusion Types of abdominal wall ernias Description Strangulation Risk IncisionalThrough an area weakened by prior surgery. Low UmbilicalCongenital defect of the abdominal wall seen in infants Low as a swelling at the umbilicus. Paraumbilical Acquired defect above or below the umbilicus. High Femoral Herniation through the femoral canal which appears belowHigh and lateral to the pubic tubercle. More common in women than men. InguinalTypically seen ‘above and medial to the pubic tubercle’. Swelling is Depends caused by weakness in the abdominal wall in the area of Hasselbach’s triangle.
Epidemiology
- Male ; Female by 9 to 1 ratio (indirect inguinal hernia most common for both sexes)
- Lifetime incidence: 5-25% percent of males, 2% of females
- Bimodal peaks before 1 year of age and then again after 40
- Groin hernias (femoral and inguinal) = 75% of abdominal wall hernias
- Inguinal hernias account for 70-95% groin hernias; of these (2/3 of these indirect, see below)
- Bilateral in 20% of cases
90% of cases in children and young adults have indirect inguinal hernias. As age of patient increases, so does incidence of acquired (direct) hernias. Risk factors: chronically increased intra-abdominal pressure (such as caused by obesity, pregnancy, and ascites); reduced muscle tone and deterioration of connective tissue (due to aging, systemic disease, malnutrition, or smoking).
Pediatrics: Approximately 3% to 5% of full-term infants and up to 30% of preterm infants will have an inguinal hernia. Presents within first 6 mths with an asymptomatic groin mass or more acutely with abdominal pain and vomiting due to incarceration. More common in boys, premature infants and on the right.
Bilateral disease incidence between 5% and 30%. An incarcerated inguinal hernia is the commonest cause of intestinal obstruction from the 1st week to the 5th month of life This ILM will focus on indirect and direct inguinal hernias. Inguinal Canal Anatomy
Canal has the following boundaries Anterior – aponeurosis of external oblique Posterior – conjoint tendon, combined tendon of internal oblique and transversus abdominis Roof – arching fibers of internal oblique and transversus abdominis Floor – inguinal ligament
Medially – pubic symphisis Laterally – anterior superior iliac spine Superficial ring – lies superior to the pubic tubercle Deep ring – lies superior to midpoint of inguinal ligament. This point is midway between pubic tubercle and ipsilateral anterior superior iliac spine. From Madden JL: Abdominal Wall Hernias: An Atlas of Anatomy and Repair. Philadelphia, WB Saunders, 1989. Hasselbach’s Triangle defined by Medially – lateral border of rectus abdominis Laterally – inferior epigastric vessels Base – inguinal ligament Inguinal Canal Contents Men – Spermatic cord structures (vas deferens, testicular artery, testicular vein, ilioinguinal nerve, genital branch of genitofemoral nerve, lymphatics and sympathetic plexus)
Women – Round ligament of the uterus, ilioinguinal nerve, genital branch of genitofemoral nerve, lymphatics and sympathetic plexus •Canal courses from lateral to medial, deep to superficial, and cephalad to caudad Indirect Hernia: The hernia develops at the internal ring, which is the site where the spermatic cord in males or the round ligament in females exits the abdomen.
The origin is lateral to the inferior epigastric artery, in contrast to direct hernias which arise medially to the inferior epigastric vessels. •Contents: Sac of peritoneum coming through internal ring, antero-medial to the spermatic cord (or round ligament) through which omentum or bowel can enter.
Course: Sac passes outside Hasselbach’s Triangle, herniates via inguinal canal through both rings into scrotum. Herniates lateral to inferior epigastric artery. May stay in canal, exit ring, and even enter scrotum.
Pathophysiology: Usually congenital (though may not become apparent until later in life).
During embryologic development, the spermatic cord and testis in men (or the round ligament in women) migrate from the retroperitoneum through the anterior abdominal wall to the inguinal canal along with a projection of peritoneum (processus vaginalis). The internal ring normally closes following the migration of the testicle into the canal and then into the scrotum. Failure to close provides the necessary defect (an area of potential weakness) through which an indirect inguinal hernia may form. The processus vaginalis may persist in up to 20% of adults, further predisposing to hernia formation.
- Prematurity and low birth weight are risk factors.
- Risk: Higher risk of incarceration/strangulation if hernia large and extends into scrotum.
- Epidemiology: Often children and young males
- Presentation: Soft swelling in area of internal ring; pain on straining; hernia comes down canal and touches fingertip on examination. Direct Hernia
- Contents: Retroperitoneal fat; less commonly, peritoneal sac containing bowel
Course: Hernia sac passes within Hasselbach’s Triangle; breaches posterior inguinal wall (bulges “directly” through abdominal wall); passes medial to inferior epigastric artery; Goes through external inguinal ring only. Pathophysiology: Acquired defect in transversus abdominis muscle; bulging as a result of weakness of the posterior floor of the inguinal canal, anywhere from the internal ring to the pubic bone. Straining to urinate or defecate, coughing, and heavy lifting have been implicated as causative factors, leading to trauma and weakening of the inguinal floor.
Risk: Usually at low (but not zero) risk for incarceration or strangulation.
Epidemiology: less common than indirect inguinal; males ; females; more common in those ; 40. Presentation: Bulge in area of Hesselbach triangle; usually painless; easily reduced; hernia bulges anteriorly, pushes against side of finger on examination. Symptoms of direct and indirect hernias
- Bulge that enlarges when stand or strain, but can be asymptomatic
- Pain or dull sensation in groin
- Patients can present with complication (obstruction or strangulation–>10-20% of pts with inguinal hernia present with strangulation)
- Extreme pain related to a hernia in the absence of incarceration and intestinal vascular compromise is unusual and should raise the suspicion of an alternative cause of the pain.
- Indirect inguinal Hernia Direct Inguinal Hernia Complications
Bowel incarceration Irreducible, but without signs of obstruction or strangulation Common symptoms include vague discomfort or intestinal issues; possibly pain, edema extending to the scrotum, nausea, vomiting and low-grade fever If the inguinal mass can be palpated separately from the testes, then it is possible to diagnose an inguinal hernia clinically. Causes: adhesions, chronicity, neck that is narrow but wide enough not to strangulate
Small Bowel Obstruction
Nausea, vomiting, abdominal distension, obstipation, and abdominal pain Prominent hernia might be apparent but can be difficult to detect in the obese patient or if the hernia is femoral. Reduction only attempted under adequate sedation and analgesia taking care not to put too much pressure lest you cause an intestinal rupture Usually urgent surgical repair
Strangulation Compromised vascular supply with gangrenous bowel Surgical emergency Presentation: irreducible hernia, inflammation (red, painful, tenderness) signs of obstruction and dehydration… epsis/toxicity 50% indirect, 3-10% direct, These rates remind us of the anatomy (the indirect come through narrow neck; the direct come through wide neck). Treatment
- Incidence of discomfort and complications increase with time
- 66% painful at first presentation–>90% painful for those who have had hernia for ten years
- Likelihood of irreducibility 6. 5% at 1 yr, 30% at 30yrs
- Whether asymptomatic hernias should be surgically repaired is still under debate
- Repaired by traditional tissue-based or by mesh procedures and by either open or laparoscopic approaches. Recurrence: risk factors for tissue deterioration, such as malnutrition, liver or renal failure, steroid therapy, and malignancies.
Questions: (1) Is the mass truly a hernia? (2) Is the hernia reducible or incarcerated? (3) Is the vascular supply to the bowel strangulated? Quiz yourself 1) What abdominal wall layers must be incised at the pubic hairline (near the midline) in order to access the abdominal cavity?
A midline incision would pass through skin, superficial fascia (outer fatty and inner membranous layers), linea alba, transversalis fascia, extraperitoneal connective tissue, median umbilical ligament, and parietal peritoneum. ) What caused the bulge in Mr. Strain? What body layers would surround it as it proceeded into the scrotum and what abdominal layers are they derived from?
Bulge most likely caused by a loop of small intestine that traversed the inguinal canal The body layers surrounding the intestinal bulge in the scrotum are: skin, dartos muscle, membranous layer of the superficial fascia, external spermatic fascia (from the external oblique aponeurosis), the cremasteric fascia (from the internal oblique aponeurosis), and the internal spermatic fascia (from the transversalis fascia)
