is a complex structure composed primarily of muscle, bone and fascia . Its major function is to protect the enclosed organs of the gastrointestinal and urogenital tracts but a secondary role is mobility, being able to flex, extend, rotate and vary its capacity
THE ABDOMINAL WALL
Anatomical causes of abdominal wall herniation1-natural weaknesses caused by inadequate muscular strength are the lumbar triangles and the posterior wall of the inguinal canal e.g inguinal hernia, oesophagus hiatus hernia, femoral vessels femoral hernia, obturator nerve obturator hernia, sciatic nerve sciatic hernia. 2- developmental failure of the processus vaginalis to close (inguinal hernia), other examples are diaphragmatic, umbilical and epigastric hernias. 3-The risk of inguinal hernia is related to the anatomical shape of the pelvis and is higher in patients having a wider and shorter pelvis. 4-sharp trauma. 5-Primary muscle pathology and neurological conditions can lead to muscle weakness and occasionally present to the surgeon as a ‘hernia’ 6-Genetic weakness of collagen 7-Weakness due to ageing and pregnancy 8-Excessive intra-abdominal pressure?
ABDOMINAL HERNIA
A hernia is the bulging of part of the contents of the abdominal cavity through a weakness in the abdominal wall.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
Neck of the sac is the narrowest part of the hernial defect. A small defect with rigid walls traps the content and prevents it from freely moving in and out of the defect, increasing the risk of complications.
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 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 mortalityAn interstitial occurs when the hernia extends between the layers of muscle and not directly through them e,g a Spigelian herniainternal is a termed used when adhesions form within the peritoneal cavity leading to abnormal pockets into which bowel can enter and become trapped
Clinical diagnosis
Historya lump on the abdominal wall under the skinPainless, aching or heavy feeling -Severe pain should alert the surgeon to a high risk of strangulation -recurrence after previous surgery - General questions regarding the cardiac and respiratory systems are necessary to assess a patient’s anaesthetic risk. - In a male with a groin hernia, history of prostatic symptoms indicates a high risk of postoperative urinary retention.Examination for hernia The patient should be examined lying down initially and then standing as this will usually increase hernia size.Check for (reducibility)The patient is asked to cough (cough impulse), when an occult hernia may appear. It may be –ve in irreducible herniaIf bruising of the overlying skin is present this may suggest venous engorgement of the contentoverlying cellulitis and tenderness then hernia content is strangulatingSigns of previous repairScrotal content for groin herniaInvestigations1-Plain x-ray of the abdomen is of little value2-Ultrasound scan may be helpful in cases of irreducible hernia3-Computed tomography scanning is helpful in complex incisionalhernia4-Contrast barium radiology is occasionally useful in the absence of CT,a herniagram5-Magnetic resonance imaging (MRI) can help in the diagnosis of sportsman’s groin6-Laparoscopy can determine the presence of an occult contralateral hernia
Management Not all hernias require surgical repair Patients :relief of symptoms of discomfort, cosmesis or to establish the diagnosis when in doubt The surgeon: should recommend repair when complications are likely, the most worrying being strangulation with bowel obstruction and bowel infarction. All cases of femoral hernia, with high risk of strangulation, should be repaired surgically Surgery should be offered to younger adult patients as symptoms and complications are likely over time
Operative approaches to hernia
All surgical repairs follow the same basic principles: 1- Reduction of the hernia content into the abdominal cavity with removal of any non-viable tissue and bowel repair if necessary; 2- Excision and closure of a peritoneal sac if present or replacing it deep to the muscles; herniotomy 3- Reapproximation of the walls of the neck of the hernia if possible; herniorraphy 4- Permanent reinforcement of the abdominal wall defect with sutures or mesh. hernioplasty
Inguinal hernia
is the most common hernia in men and women but much more common in menTypes – lateral (oblique, indirect, congenital); medial (direct, acquired), sliding, pantaloon hernia 1-Indirect herniaAs the testis descends through the inguinal canal, a tube of peritoneum is pulled with the testis and wraps around it ultimately to form the tunica vaginalis. This peritoneal tube should obliterate, possibly under hormonal control, but it commonly fails to fuse either in part or totally. Inguinal hernia in neonates and young children is always of this typeis lateral as its origin is lateral to the inferior epigastric vessels. Types: 1- Bubonocele 2- Funicular 3- Complete2- direct , medial or acquired inguinal hernia. is a result of stretching and weakening of the posterior wall of the inguinal canal just medial to the inferior epigastric (IE) vessels where there is only transversalis fascia covered by the external oblique aponeurosis (hasselbach’s triangle).is more likely in elderly patients. It has a wide neck and therefore unlikely to strangulate. The medially placed bladder can be pulled into a direct hernia 3-Sliding herniaoccurs at the deep inguinal ring lateral to the IE vessels. The posterior wall of the sac is a viscous like sigmoid colon or cecum so great care is taken during repair to avoid damage to the colon.
(pantaloon hernia). both lateral (indirect) and medial (direct) hernias are present in the same patient. 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. A patient with a single hernia has a lifetime 33 % risk of developing a hernia on the other side. Differential diagnosis of an inguinal hernia
Management of inguinal hernia
No surgery is required for early, asymptomatic, direct hernia, particularly in elderly patients who do not wish surgical intervention. Surgical trusses are not recommended but may be required for occasional patients who refuse any form of surgical intervention.Elective surgery for inguinal hernia is a common and simple operation. It can be undertaken under local regional or general anaesthesiaHerniotomy In children who have lateral hernias with a persistent processus, it is sufficient only to remove and close the sac. This is called a herniotomy. In adult surgery, herniotomy alone has a high recurrence rate and some form of muscle strengthening is added (herniorrhaphy). Open suture repair 1- Bassini –Simple interrupted sutures approximating transversalis fascia and conjoint tendon to the inguinal ligament (three lines) 2- Shouldice modification of Bassini --- double breasting of the transversalis fascia (four lines) 3- Darning – continuous non absorbable suture between the conjoint tendon and inguinal ligament. 4-Desarda repair– 1-2 cm strip of external oblique apponeurosis is used to reinforce posterior wallOpen flat mesh repair Lichtenstein mesh repairOpen plug mesh repair A two-layered mesh (‘hernia system’)Open preperitoneal repairLaparoscopic inguinal hernia repair totally extraperitoneal (TEP)transabdominal preperitoneal (TAPP) approach The mesh covers Hasselbach’s triangle, the deep inguinal ring and the femoral canal.