Abdominal hernia

ABDOMINAL HERNIA

Professor Maitham AL khateeb Consultant surgeon 2017

Definition: A hernia is the bulging of part of the contents of the abdominal cavity through a weakness in the abdominal wall. Or A protrusion of a viscus or part of a viscus through a defect in the abdominal wall musculature or a weak natural pathway in the abdominal wall.

Anatomical causes of abdominal wall Herniation

Inspite of the complex design of the abdominal wall, the only natural weaknesses caused by inadequate muscular strength are the lumbar triangles and the posterior wall of the inguinal canal

Many structures pass into and out of the abdominal cavity creating weakness which can lead to hernia Most common example is the inguinal canal in the male along which the testis descends from abdomen to scrotum at the time of birth. The testicular artery, vein and vas pass though this canal (the round ligament in the female). 80 per cent of all hernia repairs are for inguinal hernia 
Other examples are: oesophagus ( hiatus hernia ), femoral vessels ( femoral hernia ), (obturator nerve ( obturator hernia ), sciatic nerve ( sciatic hernia


Common principles in abdominal hernia:An abdominal wall hernia has two essential components: a defect in the wall and content, that is tissue which has been forced outwards through the defect.The weakness may be entirely in muscle, such as an incisional hernia It may also be In fascia, like an epigastric hernia through the linea alba, or the defect may have a bony component, such as a femoral hernia.The defect varies in size and may be very small or indeed very large.The content of the hernia may be tissue from the extraperitoneal space alone, such as fat within an epigastric hernia or a part of urinary bladder wall as in a direct inguinal hernia. However, if such a hernia enlarges then peritoneum may also be pulled into the hernia secondarily along with intraperitoneal structures such as bowel or omentum; a good example is a ‘sliding type’ of inguinal herniaMore commonly, when peritoneum is lying immediately deep to the abdominal wall weakness, pressure forces the peritoneum through the defect and into the subcutaneous tissues. This ‘sac’ of peritoneum allows bowel and omentum to pass through the defect easily .

Types of hernia by complexity: - Occult – not detectable clinically; may cause severe pain- Reducible – a swelling which appears and disappears- Irreducible – a swelling which cannot be replaced into 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- Obstructed- irreducible hernia with intestinal obstruction- Incarcerated- irreducible non obstructed may complicate In most hernia cases, the intraperitoneal organs can move freely in and out of the hernia, a ‘reducible’ hernia, but if adhesions form or the defect is small, bowel can become trapped and unable to return to the main peritoneal cavity, an ‘irreducible’ hernia, with high risk of further complications.The narrowest part of the sac,( is at the abdominal wall defect ), is called the ‘neck of the sac’When tissue is trapped inside a hernia it is in a confined Space The narrow neck acts as a (constriction ring) impeding venous return and increasing pressure within the hernia the resulting tension leads to pain and tenderness. If the hernia contains bowel then it may become ‘obstructed’, partially or totally.If the pressure rises sufficiently, arterial blood will not be able to enter the hernia and the contents become ischaemic and may infarct. The hernia is then said to have ‘strangulated’.The risk of strangulation is highest in hernias which have a small neck of rigid tissue leading first to irreducibility and then to strangulation.

The term ‘incarcerated’ hernia is not a clearly defined nomenclature and used to imply a hernia which is irreducible and developing towards strangulation . In Richter’s hernia only part of the bowel wall circumference will enters the hernia Bowel obstruction may not be present but the bowel wall may still become necrotic and perforate with life-threatening consequences. Femoral hernia may Present in this way often with diagnostic delay and high risk to the patient .

An interstitial hernia: occurs when the hernia extends or passes between the layers of the abdominal wall muscles and not directly through them. This is typical of a Spigelian hernia


An internal hernia: is a term used when adhesions form within the peritoneal cavity leading to abnormal pockets into which bowel can enter and become trapped another example is the passage of a loop of small bowel through the foramen of winslow or the mesentery of large or small bowel leading to mechanical intestinal obstruction . As there is no defect within the abdominal wall muscles the name of hernia may be cofusing

Clinical history and diagnosis in hernia cases : Patients are usually aware of a lump on the abdominal wall under the skin, therefore Self-diagnosis is common

The hernia is usually painless but patients may complain of an aching pain or heavy feeling Sharp, intermittent pain suggest pinching of tissue Severe pain should alert the surgeon to a high risk of strangulation The surgeon should determine whether the hernia reduces spontaneously or needs to be helped ,and the patient should be asked about symptoms which might suggest bowel obstruction (pain, vomiting ,distention ,and constipation) It is important to know if this is a primary hernia or whether it is a recurrence after previous surgery. Recurrent hernia is more difficult to treat and may require a different surgical approach.


Examination for hernia The patient should be examined lying down flat initially and then standing as this will usually increases the hernia size and becomes more obvious. In some cases no hernia will be apparent with the patient lying flat. The patient is asked to cough, when an occult hernia may appear, this is called visible cough impulse . Gentle pressure is applied to the lump and the patient is asked to cough again In most cases a cough impulse is felt palpable cough impulse , In cases where the neck is tight and the hernia is irreducible there may be no cough impulse, This can lead to failure of diagnosis and this is typical of femoral hernia where lack of an impulse leads the clinician to misdiagnose the case as a lymph node. In contrast cough impulse can also occur in a saphena varix which may be referred to a surgeon as a suspected Inguinal hernia. The overlying skin is usually of normal colour. If bruising is present this may suggest venous engorgement of the content and If any sign of inflammation is found over the swelling the case should be treated as an emergency( strangulation )

Examination- A swelling with a cough impulse is not necessarily a hernia- A swelling with no cough impulse may still be a hernia If the patient, on lying down flat, the hernia does not reduce spontaneously, the surgeon should ask the patient to attempt self reduction of the hernia as he may be well practised in this task while the surgeon might cause unnecessary discomfort. If neither the patient nor surgeon can reduce the hernia then treatment should be more urgent (incarcerated hernia)Investigations- Plain x-ray – of little value- Ultrasound scan – low cost, operator dependent- CT scan- in complex incisional hernia- MRI scan – good in sportsman’s groin with pain- Contrast radiology – in absence of CT scan- Laparoscopy

Plain x-ray: of the abdomen is of little value, although useful in hiatus hernia and other diaphragmatic Hernia which may be seen on chest x-ray . Ultrasound scan : may be helpful in cases of irreducible hernia, where the differential diagnosis includes a mass or fluid collection, or when the nature of the hernia content is in doubt. Computed tomography scanning: is helpful in complex incisional hernia, determining the number and size of muscle defects, identifying the content, giving some indications of the presence of adhesions and excluding other intra-abdominal pathology such as ascites, occult malignancy, portal hypertension, etc. Contrast barium radiology: is occasionally useful in the absence of CT scan. Magnetic resonance imaging (MRI): can help in the diagnosis of sportsman’s groin where pain is the Presenting feature and the surgeon needs to distinguish an occult hernia from an orthopaedic injury. Laparoscopy: it self may be used. In incisional hernia, initial laparoscopy may determine that a laparoscopic approach is feasible or not depending on the extent of adhesions.

Mesh in hernia repairThe term ‘mesh’ refers to prosthetic material, either a net or a flat sheet which is used to strengthen a hernia repair.Mesh can be used :• to bridge a defect: the mesh is simply fixed over the defect as a tension-free patch• to plug a defect: a plug of mesh is pushed into the defectA well-placed mesh should have good overlap around all margins of the defect, at least 2 cm but up to 5 cm if possible( on lay). Suturing a mesh edge-to-edge into the defect with no overlap, is not recommended Mesh plug operations are fast, but plugs can form a dense ‘meshoma’ of plug and collagen. Other complications include : - migration, - erosion into adjacent organs, - fistula formation - Chronic pain

Mesh types: 1-Synthetic mesh: The majority of meshes used today are synthetic polymers of: Polypropylene polyester polytetrafluoroethylene (PTFE) Polypropylene: makes a strong monofilament mesh It does not have any antibacterial properties but its hydrophobic nature and monofilament microstructure impede bacterial ingrowth


The term ‘mesh shrinkage’ is often used to describe a progressive decrease in size of a mesh over time. It is due to natural contraction of fibrous tissue embedded in the mesh, reducing the area of mesh itself. This Can lead to tissue tension and pain ,which is a complication of mesh repair, It can also lead to hernia recurrence if the mesh no longer covers the defect. Meshes can shrink by up to 50 percent of it’s original size and, in occasional cases, even more.

Meshes with (thinner strands and larger spaces between them) ‘lightweight, large-pore meshes’, are preferred as they have better tissue integration, less shrinkage, more flexibility and improved comfort.2-Biological meshwhich are sheets of sterilised ,decellularised , non-immunogenic connective tissue. They are derived from human or animal dermis, bovine pericardium or porcine intestinal submucosa. They provide a ‘scaffold’ to encourage neovascular in-growth and new collagen deposition. Host enzymes eventually break down the biological implant which is replaced and remodelled with ‘normal’ host fibrous tissue.Mesh characteristics:- Woven , knitted or sheet- Synthetic or biological – mainly synthetic- Light, medium or heavyweight – lightweight becoming more popular- Large pore, small pore – large pore causes less fibrosis and pain- Intraperitoneal use or not – non-adhesive mesh on one side- Non-absorbable or absorbable – mainly non-absorbable


Positioning the mesh:The strength of a mesh repair depends on host–tissue in-growth .Meshes should be placed on a firm, well-vascularised tissue bed With generous overlap of the defect. The mesh can be placed:• just outside of the muscle in the subcutaneous space (on lay);• within the defect (inlay) – only applies to mesh plugs Small defects;• between fascial layers in the abdominal wall (intraparietal or sublay);• immediately extraperitoneally, against muscle or fascia (also sublay);• Intraperitoneally.At open surgery all of these planes are used, but laparoscopic surgeons currently only use intraperitoneal or extraperitoneal planes

Limitations to the use of mesh: The presence of infection limits the use of mesh, particularly heavyweight types. If a mesh becomes infected then it often needs to be removed. Some infected meshes can be salvaged using a combination of debridement of non-incorporated mesh, appropriate antibiotics and modern vacuum-assisted dressings.

Divarication herniais nothing but attenuated stretched linea alba above the umbilicus usually, which bulges out with any rise in intra abdominal pressure like coughing or sneezing and is best seen by asking a supine patient to simply lift his head off the pillow (head raising test) there is no sac and no contents just stretched weak linea alba .It is common in multiparous females, for cosmetic reasons it can be treated conservatively by abdominal binder or surgically by the open or closed repair .

Inguinal herniaIs the most common hernia in men and women but much more common in men. There are two basic types which are fundamentally different in anatomy, causation and complications However, they are anatomically very close to one another, surgical repair techniques are very similar and ultimate reinforcement of the weakened anatomy is identical so they are often referred to together as inguinal herniaThe congenital inguinal hernia is known as indirect, oblique or lateral while the acquired hernia is called direct or medial. There is a third ‘sliding’ hernia which is acquired but is lateral in position Basic anatomy of the inguinal canalAs the testis descends from the abdominal cavity to the scrotum in the male it first passes through a circle shaped defect called the deep inguinal ring in the transversalis fascia, just deep to the abdominal musclesThe inferior epigastric vessels lie just medial to the deep inguinal ring

Three important nerves pass through the inguinal canal: 1 - the ilioinguinal nerve 2 - the iliohypogastric nerve 3 - the genital branch of the genitofemoral nerve As the testis descends down to the scrotum, a tube of peritoneum(processus vaginalis) is pulled with the testis and wraps around it ultimately to form the tunica vaginalis.This peritoneal tube should be obliterated, possibly under hormonal control before delivery, but it commonly fails to fuse either in part or totally , leading to indirect inguinal hernia later on. Inguinal hernia in neonates and young children is always of this congenital type. However , in other patients, the muscles around the deep inguinal ring are able to prevent a hernia from developing until later in life when under the constant positive abdominal pressure, the deep inguinal ring and muscles are stretched and a hernia becomes apparent(indirect inguinal hernia) As the hernia increases in size, the contents are directed down into the scrotum. These hernias can become massive and may be referred to as a scrotal hernia

The second type of inguinal hernia, referred to as direct or medial, is acquiredIt is a result of stretching and weakening of the abdominal wall just medial to the inferior epigastric (IE) vessels

A direct, medial hernia is more likely in elderly patients. It is broadly based and therefore unlikely to strangulate. The medially placed bladder can be pulled into a direct hernia

The third type of inguinal hernia is referred to as a sliding hernia. This is also an acquired hernia due to abdominal wall weakness but this occurs in deep inguinal ring lateral to the IE vessels. On the left side, sigmoid colon may be pulled into a sliding hernia and on the right side the caecum. Surgeons need extra caution during repair.Occasionally, both lateral and medial hernias are present in the same patient (pantaloon hernia).


Surgeons will often accept the diagnosis on history alone but re-examination at a later date or investigation by ultrasound scan may be requested. If an inguinal hernia becomes irreducible and tense there may be no cough impulse.
Differential diagnosis of inguinal hernia: -a lymph node -groin mass -abdominal mass -a hydrocele or other testicular swelling -Femoral hernia or spigelian hernia -a saphena varix -a varicocoele



Ten per cent of all patients will present with bilateral inguinal hernias and up to 20 per cent more will have an occult contralateral hernia (on laparoscopic evaluation)

Ninety-five per cent of inguinal hernia patients present at clinics as a cold case and only 5 per cent present as an emergency with a painful irreducible hernia which may progress to strangulation and possible bowel infarction and should be dealt with as emergency
Complications of surgery: Early – pain, bleeding, urinary retention, anaesthetic related complications Medium – seroma, wound infection Late – chronic pain, testicular atrophy ,skin paraesthesia

Femoral hernia:The walls of a femoral canal are : - The femoral vein laterally - The inguinal ligament anteriorly - The pelvic bone covered by the ileopectineal ligament (Astley Cooper’s) posteriorly - the lacunar ligament (Gimbernat’s) mediallyThe lacunar ligament is a strong curved ligament with a sharp unyielding edge which impedes reduction of a femoral hernia

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Differential diagnosis: Direct inguinal hernia Lymph node Saphena varix Femoral artery aneurysm Psoas abscess Rupture of adductor longus muscle or tendon with a haematoma All patients with unexplained small bowel obstruction should undergo careful examination for a femoral hernia, in suspicious cases CT scan may be indicated There is no alternative to surgery for femoral hernia and it is wise to treat such cases with some urgency There are three open approaches and in the appropriate cases can be managed laparoscopically 1-Low approach (Lockwood) : This is the simplest operation for femoral hernia but only suitable when there is no risk of bowel resection


VENTRAL HERNIA:- Umbilical – paraumbilical- Epigastric- Incisional- Parastomal- Spigelian- Lumbar-TraumaticThis 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 dorsolateralUmbilical herniaThe umbilical defect is present at birth but closes as the stump of the umbilical cord heals, usually within a week of birth. This process may be delayed, leading to the development of herniation in the neonatal period. The umbilical ring may also stretch and reopen in adult life This common condition occurs in up to 10 per cent of infants, with a higher incidence in premature babies. The hernia appears within a few weeks of birth and is often symptomless but increases in size on crying and assumes a classical conical shape. Sexes are equally affected but the incidence in black infants is up to eight times higher than in white. Obstruction and/or strangulation are extremely uncommon below the age of three years.

Treatment: Conservative treatment is indicated under the age of two years when the hernia is symptomless. Parental reassurance is all that is necessary Ninety-five per cent of hernias will resolve spontaneously If the hernia persists beyond the age of two years it is unlikely to resolve and surgical repair is indicated Conditions which cause stretching and thinning of the midline raphe (linea alba), such as pregnancy, obesity and liver disease with cirrhosis, predispose to reopening of the umbilical defect In adults Mayo repair. Two -layered (double breasted) repair Non-absorbable sutures are used. For defects larger than 2 cm in diameter, mesh repair is recommended Repair can be either open repair or laparoscopic repair. Laparoscopic umbilical hernia repair

Epigastric hernia These arise through a defect in 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 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 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 patients are often fit, healthy males between 25 and 40 years of age. These hernias can be very painful even when the swelling is the size of a pea due to the fatty contents becoming nipped sufficiently to produce partial strangulation. The pain may mimic that of a peptic ulcer but symptoms should not be attributed to the hernia until gastrointestinal pathology has been excluded On examination: A soft midline swelling can often be felt more easily than it can be seen. It may be locally tender. It is unlikely to be reducible because of the narrow neck. It may resemble a lipoma. A cough impulse may or may not be felt. Very small epigastric hernias have been known to disappear spontaneously, probably due to infarction of the fat. surgery should only be offered if the hernia is sufficiently symptomatic.


Incisional hernia:These arise through a defect in the musculofascial layers of the abdominal wall in the region of a postoperative scar. Thus they may appear anywhere on the abdominal surface, Incisional hernias have been reported in 10–50 per cent of laparotomy incisions and 1–5 per cent of laparoscopic port-site incisionsFactors predisposing to their development are:- Patient factors : obesity, (general poor healing) due to malnutrition, immunosuppression or steroid therapy, chronic cough, cancer-wound factors : (poor quality tissues, wound infection)-Surgical factors : (inappropriate suture material, incorrect suture placement)An incisional hernia usually starts as disruption of the musculofascial layers of a wound in the early postoperative period. Many incisional hernias may be preventable with the use of good surgical technique. The classic sign of wound disruption is a serosanguinous discharge.These hernias commonly appear as a localised swelling involving a small portion of the scar but may present as a diffuse bulging of the whole length of the incisionIncisional hernias tend to increase steadily in size with time. The skin overlying large hernias may become thin and atrophicio

Attacks of partial intestinal obstruction are common as there are usually coexisting internal adhesions. Strangulation is less frequent


Spigelian hernia:These hernias are uncommon although are probably underdiagnosed. They affect men and women equally and can occur at any age, but are most common in the elderlyThey arise through a defect in the Spigelian fascia which is the aponeurosis of the transversus abdominis muscleMost Spigelian hernias appear below the level of the umbilicus near the edge of the rectus sheath but they can be found anywhere along the ‘Spigelian line’

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

Less commonly, the sac comes through the superior lumbar triangle, which is bounded by the 12th rib above, medially by the sacrospinalis and laterally by the posterior border of the internal oblique muscle, Primary lumbar hernias are rare, but may be mimicked by incisional hernias arising through flank incisions for renal operations or through incisions for bone grafts harvested from the iliac crest.A lumbar hernia must be distinguished from:• a lipoma• a cold (tuberculous) abscess pointing to this position;• pseudo-hernia due to local muscular paralysis ,the most common cause being injury to the sub costal nerve during a renal operationsurgery is recommended because the natural history for these hernias is to increase in size Lumbar hernias can be approached by open or laparoscopic surgery. The defects can be difficult to close with sutures and mesh is recommended Lumbar incisional hernias: can be approached in the same way

Parastomal hernia When surgeons create a stoma, such as a colostomy or ileostomy, they are effectively creating a hernia by bringing bowel out through the abdominal wall The rate of parastomal hernia is over 50 % The ideal surgical solution for the patient is to rejoin the bowel and remove the stoma altogether but this is not always possible Various open suture and mesh techniques have been described to repair parastomal hernia but failure rates are high. Laparoscopic repair is also possible

Traumatic hernia: These hernias arise through non-anatomic defects caused by injury. They can be classified into three types: 1- Hernias through abdominal stab wound sites.(These are effectively incisional hernias) 2- Hernias protruding through splits or tears in the abdominal muscles following blunt trauma. 3- Abdominal bulging secondary to muscle atrophy which occurs as a result of nerve injury or other traumatic denervation The key to the aetiology is in the history and the non-anatomic location of the hernia Surgery may be justified if the hernia is sufficiently symptomatic or it has a narrow neck

Rare external hernias:Perineal herniaThis 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. A combined abdominoperineal operation is generally the most satisfactory for the last two types of hernia

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 The swelling is liable to be overlooked because it is covered by the pectineus muscle It seldom causes a definite swelling . Strangulated obturator hernia occurs in more than 50% of the cases. pain is referred along the obturator nerve by its geniculate branch to the knee joint On vaginal or rectal examination the hernia can sometimes be felt as a tender swelling in the region of the obturator foramen These hernias have often undergone strangulation, frequently of the Richter type, by the time of presentation Operation is indicated: The diagnosis is rarely made preoperatively and so it is often approached through a laparotomy incision It is best closed using a mesh plug

Gluteal and sciatic hernias:Both of these hernias are very rare. A gluteal hernia passes through the greater sciatic foramen, either above or below the piriformis muscle A sciatic hernia passes through the lesser sciatic foramenDifferential diagnosis must be made between these conditions and:• a lipoma or other soft tissue tumour beneath the gluteus maximus;• a tuberculous abscess• a gluteal aneurysmAll doubtful swellings in this situation can be characterized with CT scanning but, if in doubt, they should be explored by operation