Hernia.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 Ventral Hernias Ventral hernias: This term refers to hernias of the anterior abdominal wall. Inguinal and femoral hernias are not included even though they are ventral. Lumbar hernia is included despite being dorsolateral. Ventral hernias include: Umbilical Paraumbilical Epigastric Incisional Spigelian Parastomal Lumbar Traumatic Umbilical hernia: in children: Common in infants and most resolve spontaneously. Rarely strangulates. in adults: Common in overweight men or multiparous women. Progressively increase in size and may get very large indeed. Round defect with rigid fibrous margins. Surgery advised because of risk of strangulation Para-umbilical hernia: This is an acquired hernia that occurs just above or below the umbilicus (usually above). It especially occurs in obese, multiparous, middle-aged women. The neck is narrow and, like a femoral hernia, it is particularly prone to become irreducible or strangulated. The contents are nearly always the omentum, and often in addition transverse colon and small intestine. A characteristic feature of paraumbilical hernias on clinical exam is the “crescent sign” Paraumbilical hernia Umbilical hernia Key point… The main difference between umbilical and para-umbilical hernias is the location of defect; In para-umbilical hernias, the defect is in the linea alba. In umbilical hernias, the defect is in the umbilical scar itself. Treatment of para-umbilical hernia: For defects < 2 cm: The sac is excised and the edges of the rectus sheath are overlapped above and below the hernia (Mayo's operation). For defects > 2 cm: mesh repair is recommended Epigastric hernia: These arise through the midline raphe (linea alba) anywhere between the xiphoid process and the umbilicus, usually midway. When close to the umbilicus they are called supraumbilical hernias. Epigastric hernias begin with a transverse split in the midline raphe so, in contrast to umbilical hernias, the defect is elliptical. It has been hypothesised that the defect occurs at the site where small blood vessels pierce the linea alba or, more likely, that it arises at weaknesses due to abnormal decussation of aponeurotic fibres related to heavy physical activity.  Epigastric hernia defects are usually less than 1 cm in maximum diameter commonly contain only extraperitoneal fat which gradually enlarges, spreading in the subcutaneous plane to resemble the shape of a mushroom. When very large they may contain a peritoneal sac but rarely any bowel. More than one hernia may be present. The most common cause of ‘recurrence’ is failure to identify a second defect at the time of original repair. Peptic ulcers are a DDx! Incisional hernia: Incidence: 10–50 per cent after laparotomy Causation due to patient, wound and surgeon factors Wide variation in size Often multiple defects within the same scar Obstruction is common but strangulation is rare Open and laparoscopic repairs possible Treatment: Both open and laparoscopic options are available. A number of principles apply, irrespective of the technique used: 1. The repair should cover the whole length of the previous incision. 2. Approximation of the musculo-fascial layers should be done with minimal tension and prosthetic mesh should be used to reduce the risk of recurrence. 3. Mesh may be contraindicated in a contaminated field, e.g. bowel injury during the dissection but, in a clean-contaminated field, such as after an elective bowel resection, mesh may be used if placed in a different anatomical plane to the contamination, such as in the extra-peritoneal/retro-muscular space. 4. Appropriate systemic antibiotics should be used Spigelian hernia: Rare. Often misdiagnosed. affects men and women equally Can occur at any age, but are most common in elderly. They arise through a defect in the Spigelian fascia which is the aponeurosis of the transversus abdominis muscle. High risk of strangulation, so surgery is recommended. Lumbar hernia: Most primary lumbar hernias occur through the inferior lumbar triangle of Petit bounded below by the crest of the ilium, laterally by the external oblique muscle and medially by the latissimus dorsi. Parastomal hernia: When surgeons create a stoma, they are effectively creating a hernia by bringing bowel out through the abdominal wall. The muscle defect created tends to increase in size over time and can ultimately lead to massive herniation around the stoma. Traumatic hernia: These hernias arise through defects caused by injury. They can be classified into three types: 1. Hernias following abdominal stab wounds. 2. Hernias following blunt trauma. 3. Hernias secondary to muscle atrophy which occurs as a result of nerve injury or other traumatic denervation. Akin to the lumbar pseudo-hernia seen after open nephrectomy, these can arise following chest injury with damage to the intercostal nerves. Diagnosis: The key to the aetiology is in the history and the non- anatomic location of the hernia. Treatment: Surgery may be justified if the hernia is sufficiently symptomatic, or if investigations suggest a narrow neck and hence a risk of obstruction or strangulation. Stab wound traumatic hernias are straightforward to repair using open or laparoscopic techiques as for other ventral hernias. Other hernias/conditions: Divarification of the recti: It is the condition where the linea alba stretches laterally as the two rectus muscles separate. It occurs in the upper abdomen in middle-aged, over- weight men but also as a result of birth trauma in the female when it occurs below the umbilicus. Perineal hernia: This type of hernia is very rare and includes: postoperative hernia through a perineal scar, which may occur after excision of the rectum median sliding perineal hernia, which is a complete prolapse of the rectum anterolateral perineal hernia, which occurs in women and presents as a swelling of the labium majus posterolateral perineal hernia, which passes through the levator ani to enter the ischiorectal fossa. Sportsman’s hernia: This specific entity is well described and presents as severe pain in the groin area, extending into the scrotum and upper thigh. It is almost entirely restricted to young men who play contact sports such as football and rugby. The pain can be debilitating and prevent the patient from exercising. In most cases, the pain is due to an orthopaedic injury, such as adductor strain or pubic symphasis diastasis. However, some believe that it can be due to muscle tearing (Gilmore’s groin) or stretching of the posterior wall of the inguinal canal. Other causes of pain should be excluded, such as hip, pelvic or lumbar spinal disease and bladder/prostate problems. MRI is the Ix of choice but ultrasonography, herniography or even laparoscopy may be used. Richter hernia: Richter hernia (partial enterocele) is the protrusion and/or strangulation of only part of the circumference of the intestine's antimesenteric border through a rigid small defect of the abdominal wall. Obturator hernia: Obturator hernia, which passes through the obturator canal, occurs six times more frequently in women than in men. Most patients are over 60 years of age. These hernias have often undergone strangulation, frequently of the Richter type, by the time of presentation. Physical exam may show the Howship- romberg sign (inner thigh pain on internal rotation of leg). Diagnosis: CT scan Treatment: Surgery is indicated. Amyand hernia: a hernia that contains appendix. Littre hernia: a hernia that contains mickel’s diverticulum. Pantaloon hernia: presence of both direct and indirect inguinal hernias in the same patient.  The Anki deck for this lecture will be available on the telegram channel!