Hernia ١ PDF

 Hernia By: Zaid Hayder Lecturer: Dr. Bassem Rassam Hernia: Definition: A bulging of part of the contents of the abdominal cavity through a weakness in the abdominal wall. Etiology: There are 2 main etiological factors that are required for the development of a hernia: 1) Weakness 2) E...

 Hernia By: Zaid Hayder Lecturer: Dr. Bassem Rassam Hernia: Definition: A bulging of part of the contents of the abdominal cavity through a weakness in the abdominal wall. Etiology: There are 2 main etiological factors that are required for the development of a hernia: 1) Weakness 2) Excessive intra-abdominal pressure In turn, this weakness could be due to: Basic design weakness (e.g: inguinal hernia) Weakness due to structures entering and leaving the abdomen (e.g: the esophagus in hiatus hernia) Developmental failure (e.g: congenital diaphragmatic hernia) Genetic weakness of collagen Sharp and blunt trauma Weakness due to ageing and pregnancy Primary neurological and muscle diseases Pathology: Any hernia consists of: I. Defect in the abdominal wall: through which the sac bulges out. II. Sac: It is a peritoneal pouch protruding through the defect & containing the protruded viscus. It consists of the fundus, body and neck. III. Content: almost any of the abdominal viscera can herniate, but the most common contents are bowel (referred to as enterocele) or omentum (referred to as omentocele)  Omentocele vs Enterocele? Omentocele Enterocele 1. Doughy or firm & slippery 1. Soft. 2. No gurgling on reduction 2. Gurgling on reduction. 3. Percussion → dull 3. Percussion → resonant 4. Easy reduction at first but 4. Difficult reduction at first difficult at the end. but easy at the end.  Basic anatomy of the abdominal wall: The roof of the abdomen is formed by: the diaphragm separating the thoracic from the abdominal cavity. Weakness of the diaphragm can lead to herniation of bowel from the area of positive pressure (abdominal cavity) to the area of negative pressure (thoracic cavity). The bony pelvis forms the floor of the cavity but a muscular central portion, the perineum, may also weaken and allow rectum, bladder and gynaecological organs to bulge downwards, a condition called prolapse. Posteriorly the muscles are strong, but there are two areas of weakness which can lead to rare lumbar hernias. These two areas are the two posterior lumbar triangles. Anteriorly the two powerful rectus abdominus muscles extend vertically from ribs to pelvis. Herniation through these strong muscles does not occur naturally but their central join, the linea alba, is an area of weakness resulting in epigastric and paraumbilical hernias. Classifications of hernia: Hernias can be classified according to: I. Site: External hernia vs Internal hernia II. According to Complexity: Occult – not detectable clinically; may cause severe pain Reducible – a swelling which appears and disappears Irreducible – a swelling which cannot be replaced in the abdomen, high risk of complications Strangulated – painful swelling with vascular compromise, requires urgent surgery Infarcted – when contents of the hernia have become gangrenous, high mortality! Key point… The difference between Irreducible hernia and strangulated hernia is that in irreducible hernias, the blood supply is NOT compromised, unlike strangulated hernias, where the interruption in blood supply may even lead to infarction!  Lecturer’s Notes: 1) To diagnose hernia, Two physical exam findings are characterstic: Reducibility A positive cough impulse, which is defined as expansion of a mass in all directions when the patient is asked to cough. This finding is typical of hernias. 2) However, not all hernias have a positive cough impulse (e.g: In cases where the neck is tight and the hernia irreducible there may be no cough impulse). And vice versa, not every cough impulse = hernia! (Cough impulse can also occur in a saphena varix) 3) Small hernias can be more dangerous than large ones. Diagnosis of hernia: The diagnosis is CLINCAL. Signs that should be sought for in clinical exam include: Reducibility Cough impulse Tenderness Overlying skin colour changes Multiple defects/contralateral side Signs of previous repair Scrotal content for groin hernia Associated pathology Investigations: For most hernias, no specific investigation is required. Only in certain cases are investigations necessary: Plain x-ray – of little value US CT – good for incisional hernias and obturator hernias. MRI – good in sportsman’s groin with pain Contrast radiology – especially for inguinal hernia Laparoscopy – useful to identify occult contra-lateral inguinal hernia Management: Not all hernias require surgical repair. Management of hernias includes either expectant or surgical management, and the choice of this treatment will depend on the type of hernia. This will be discussed in detail later on. In general, there are 3 types of surgical methods used in the Tx of hernia: Herniotomy: Excision of the sac only. Herniorhaphy: Excision of the sac + Edges of healthy muscle are sutured to close the defect. Hernioplasty: Excision of the sac + Re-enforcement by mesh. (the use of propylene mesh in Hernioplasty) All surgical repairs follow the same basic principles: 1) Identification of the sac 2) reduction of the hernia content into the abdominal cavity with removal of any non-viable tissue and bowel repair If necessary 3) excision and closure of a peritoneal sac if present or replacing it deep to the muscles 4) re-approximation of the walls of the neck of the hernia if possible 5) permanent reinforcement of the abdominal wall defect with sutures or mesh. Strangulated hernias: Definition: Interruption of the blood supply of the contents of hernia. It is the most serious complication of hernias!! The commonest hernia seen strangulated is indirect inguinal hernia as it is the commonest hernia, but the most liable hernias to be strangulated are femoral and paraumbilical hernias, due to their narrow neck. Clinical features: Painful, tender, irreducible, tense mass. Absence of cough impulse Fever, N&V. Changes in the overlying skin (erythema, warmth, edema) Features of shock! Features of intestinal obstruction Diagnosis: CLINICAL!!! There is no investigation that can reliably Dx strangulation. Treatment: URGENT TREATMENT PLEASE! Treatment includes: 1) Resuscitation: Hospitalization, IV fluid, ABs, NG decompression, foley catheter 2) Surgery Viable bowel Non-viable bowel Specific Hernia Types Inguinal Hernia Anatomy of the inguinal canal: The inguinal canal is a passage that starts from the deep inguinal ring, extends medially and inferiorly through the abdominal wall and ends in the superficial inguinal ring. As the testis descends from the abdominal cavity to the scrotum in males, it firsts passes through the deep inguinal ring into the inguinal canal. With its descent, the testis will pull a tube of peritoneum along with it. This peritoneal tube should obliterate, possibly under hormonal control, but it commonly fails to obliterate, either in part or totally. This is known as persistent processus vaginalis, and it explains the pathophysiology of indirect inguinal hernia. Walls of the inguinal canal: Anteriorly: skin, superficial fascia and external oblique aponeurosis cover the full length of the canal; the internal oblique covers its lateral third. Posteriorly: the conjoint tendon (representing the fused common aponeurotic insertion of the internal oblique and transversus abdominis muscles into the pubic crest) forms the posterior wall of the canal medially; the transversalis fascia lies laterally. Above (roof): the lowest fibers of the internal oblique and transversus abdominis. Below (floor) : the inguinal ligament. Important anatomical landmarks:  Bony landmarks: ASIS, Pubic symphysis, pubic tubercle (2-3 cm lateral to symphysis)  Mid-point of Inguinal Ligament lies midway between ASIS and pubic tubercle. It serves as a landmark for the deep inguinal ring.  Mid-inguinal point: midway between ASIS and pubic symphysis. Site of femoral artery pulsation  Superficial inguinal ring: 1.25 cm above and medial to pubic tubercle  Deep inguinal ring: 1.25 cm above and medial to mid-point of inguinal ligament  Femoral ring: 1.25 cm below and lateral to pubic tubercle Contents of the inguinal canal: In males: spermatic cord in females: round ligament of uterus Types of inguinal hernias: There are two main types of inguinal hernias; direct (aka medial) and indirect (aka lateral) inguinal hernias, and are best explained by the following table:  Indirect inguinal hernia Direct inguinal hernia Incidence The commonest hernia Less common Age Mostly pediatrics but any age Mostly elderly, never in children group could be affected Sex Males are more affected Only males Passage Passes through inguinal canal Does not pass through inguinal canal. Shape pyriform hemispherical Descent Forwards, medially and downwards. Directly forwards. Cannot descend into Can descend into scrotum. scrotum. Reduction Upwards, laterally and Directly backwards backwards. Defect Deep inguinal ring, lateral to Hasselbach's triangle, medial to inferior epigastric vessels inferior epigastric vessels. Complications Common, surgery recommended Rare, surgery not mandatory, esp. in and Tx early asymptomatic cases Treatment: In infants → herniotomy at 1 year of age In adults, operation is usually advised. This comprises excision of the sac and repair of the weakened inguinal canal, commonly performed either by: plicating the transversalis fascia in the posterior wall with a nylon suture (Shouldice repair) or by reinforcing the posterior wall with a nylon or polypropylene mesh (Lichtenstein repair). Or to place a mesh laparoscopically, covering the hernial orifice. Laparoscopy has particular advantages in the treatment of recurrent or bilateral hernias. Complications: Early – pain, bleeding, urinary retention, anaesthetic related Medium – seroma, wound infection Late – chronic pain, testicular atrophy Femoral Hernia Anatomy of Femoral ring: Borders: Anteriorly: the inguinal ligament. Medially: lacunar part of the inguinal ligament (Gimbernat's ligamentł). Laterally: the femoral vein. Posteriorly: the pectineal ligament (of Astley Cooper), which is the thickened periosteum along the superior pubic ramus. Contents: fat + a lymph node (the node of Cloquet). Femoral hernia: Less common than inguinal hernia It is more common in females than in males However, the most common type of hernia in females is inguinal hernia! Fifty per cent of cases present as an emergency with very high risk of strangulation! Easily missed on examination.  inguinal hernia Femoral hernia Incidence More common Less common Sex Males are more affected Females are more affected Relation to Above and medial to pubic Below and lateral to pubic tubercle pubic tubercle tubercle Strangulation Less common More common Differential diagnosis of femoral hernia: Direct inguinal hernia Lymph node Saphena varix Femoral artery aneurysm Psoas abscess Rupture of adductor longus with haematoma Investigations: In routine cases, no specific investigations are required. However, if there is uncertainty then US or CT should be requested. Treatment: SURGERY IS MANDATORY! It is wise to treat such cases with some urgency. There are three open approaches, in addition to a laparoscopic approach: Low approach (Lockwood) The inguinal approach (Lotheissen) High approach (McEvedy) Laparoscopic approach