Bowel obstruction & Hernias Hugh Tulloch

Learning objectives Go through the basics of hernias and bowel obstruction Anatomy Dapsicamp Focus on inguinal and femoral hernias

What is the definition of a hernia??

Hernias Definition: A protrusion of a viscus (organ) or part of a viscus through a defect in a wall that contains it.

epidemiology Comprise of 7% of all surgical outpatients 1-3% of young children (congenital) Most common in elderly men (200/10000 person years) – 75 years

Question time Names some common hernias

Common hernias Inguinal, femoral, umbilical, incisional Can further be described: Reducible Irreducible (incarcerated) Strangulated Richter’s – only lumen wall is herniated (strangulation without obstruction)

Inguinal hernias Male > female Indirect (80%) Follows normal course of inguinal canal May have congenital origin – failure of regression of processus vaginalis Direct (20%) Does not go through deep ring. Weakness in abdo wall **Above and medial to pubic tubercle**

Background - anatomy Inguinal ligament

Inguinal canal The anterior wall is formed by the aponeurosis of the external oblique, and reinforced by the internal oblique muscle laterally. The posterior wall is formed by the transversalis fascia. The roof is formed by the transversalis fascia, internal oblique and transversus abdominis. The floor is formed by the inguinal ligament (a ‘rolled up’ portion of the external oblique aponeurosis) and thickened medially by the lacunar ligament.

The two openings to the inguinal canal are known as rings. The deep (internal) ring is found above the midpoint of the inguinal ligament. which is lateral to the epigastric vessels. The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal. The superficial (external) ring marks the end of the inguinal canal, and lies just superior to the pubic tubercle. It is a triangle shaped opening, formed by the evagination of the external oblique

Contents of inguinal canal 3: arteries, nerves, fascial layers, others The structures which pass through the canal differ between males and females: in males : the spermatic cord and its coverings + the ilioinguinal nerve. in females : the round ligament of the uterus + the ilioinguinal nerve.

Spermatic cord 3 arteries: artery to vas deferens (or ductus deferens), testicular artery, cremasteric artery; 3 fascial layers: external spermatic, cremasteric, and internal spermatic fascia; 3 other structures: pampiniform plexus, vas deferens (ductus deferens), testicular lymphatics; 3 nerves: genital branch of the genitofemoral nerve (L1/2), sympathetic and visceral afferent fibres, ilioinguinal nerve (N.B. outside spermatic cord but travels next to it) Note that the ilioinguinal nerve passes through the superficial ring to descend into the scrotum, but does not formally run through the canal.

Femoral Female > male Increased risk of strangulation **Lateral and inferior to pubic tubercle** Femoral canal: Boundaries: ANTERIOR: inguinal ligament POSTERIOR: pectineal ligament MEDIAL: lacunar ligament LATERAL: femoral vein

History Onset, course, duration Painful? (Socrates) Other, previous lumps Symptoms of bowel obstruction Possible causes: COPD, cough, urinary obstruction Increase abdo pressure Does lump disappear? -reducible

Differentials Other hernias – femoral, inguinal etc Enlarged lymph nodes Ectopic testis Femoral aneurysm

Any questions?

Bowel obstruction Aetiology Can be caused by a physical blockage or due to a ‘shocked’ bowel Mechanical Physical object blocking Lumenal, extra luminal Non-mechanical Surgical Postopertaive, peritonitis, ischaemia Medical Electrolyte abnormalities Drugs – opiates, anticholinergics

Causes of mechanical obstruction

intussusception

volvulus

Gallstone ileus - cholecysto-enteric fistula ”an abnormal connection between an organ, vessel, or intestine and another structure”

In general… Small bowel Adhesions and hernias Large bowel neoplasia, diverticulitis, volvulus

Non mechanical obstruction Ileus disruption of the normal propulsive ability of the gastrointestinal tract. Paralytic ileus postsurgical ileus – gastrointestinal surgery Electrolyte imbalance Hypothyroidism Spinal cord injury

Question time What would an obstructed patient complain of?

Clinical features - symptoms 4 cardinal symptoms 1. pain Small bowel – central Large bowel – lower and colicky (if constant worry about perforation) 2. constipation (absolute) 3. vomiting 4. distention

Signs

investigations Imaging Erect CR and AXR U&Es – electrolyte abnormalities

Question time Why would you perform an erect CXR?

Erect chest xray

Abdo xray – small bowel obstruction

Large bowel obstruction

Differences… (first) (second)

Treatment - mechanical Mostly conservative Nil by mouth and NG tube Analgesia Surgery indications: Strangulation or perforation Closed loop obstruction Failure of conservative approach neoplasms

Non mechanical Conservative -prevention (reduce bowel handling in surgery) Analgesia NBM and NG tube Medical – electrolyte restoration

prognosis Depends on type.. Non-complicated have mortality 3-5% If ischaemic can be 30%

Question time What features on a AXR would indicate small bowel obstruction? Fluid levels, central position of loops, valvulae conniventes (all the way across) Where would you see a femoral hernia Below and lateral What is the definition of a hernia? A protrusion of a viscus (organ) or part of a viscus through a defect in a wall that contains it.

Case study Mr X comes in with intramittent central abdo pain. He is constipated, vomiting. On examination his stomach is distended. You also notice a lump in his groin What is your differential Inflamatory – appendicitis? Perforation of ulcer? Vascular - occlusive intestinal ischemia, usually caused by thromboembolism of the superior mesenteric artery What investigations do you order CXR, AXR What more information about the lump would you want to know Reducible? Location? Painful?

Case study Mrs Y has just undergone surgery to remove a colorectal cancer Her chart reads BNO for the last 3 days What does BNO stand for? What do you think the cause is? How should you manage her?