Core Topics in General & Emergency Surgery: Companion to Specialist Surgical Practice (17 page)
Read Core Topics in General & Emergency Surgery: Companion to Specialist Surgical Practice Online
Authors: Simon Paterson-Brown MBBS MPhil MS FRCS
An epigastric hernia is defined as a fascial defect in the linea alba between the xiphoid process and the umbilicus. The true incidence is unknown but autopsy studies have suggested a prevalence of 0.5–10% in the general population. There is a male preponderance, with a male to female ratio of approximately 4:1, with the diagnosis usually being made in the third to fifth decades.
The aetiology is related to the functional anatomy of the ‘parachute area’. The anterior abdominal wall aponeurosis consists of tendinous fibres that lie obliquely in aponeurotic sheets, allowing for changes in the shape of the abdominal wall, for example during respiration. However, the midline can change only in length and breadth, an increase in one necessitating a decrease in the other. During abdominal distension, the linea alba must increase in both dimensions, the resulting tearing of fibres possibly leading to the development of an epigastric hernia.
The majority of epigastric hernias (probably 75%) are asymptomatic. Typical symptoms, if present, include vague upper abdominal pain and nausea associated with epigastric tenderness. The symptoms tend to be more severe when the patient is lying down, attributed to traction on the hernial contents. Pain on exertion localised to the epigastrium is also a common symptom. Incarceration is common, and strangulation of pre-peritoneal fat or omentum results in localised pain and tenderness. Incarceration or strangulation of intra-abdominal viscera is extremely rare, the symptoms obviously depending on the incarcerated organ.
The presence of a midline mass on physical examination usually confirms the diagnosis. In obese patients, palpation of the mass may be difficult and confirmation of the diagnosis by ultrasound or computed tomography may be helpful.
Epigastric hernias are rare in infants and children, and asymptomatic hernias in children under the age of 10 years may resolve spontaneously. The decision for surgical intervention depends on the presence and severity of symptoms.
Small solitary defects may be approached with either a vertical or transverse incision in the midline, centred over the hernia. For larger hernias, if the defects are multiple or in the emergency setting when a strangulated viscus is suspected, a vertical incision is preferred. The hernia and its contents are dissected free of the surrounding tissues and, if present, the hernial contents examined and dealt with appropriately. If the defect is small (< 2 cm), repair by primary suture closure using non-absorbable material is usually sufficient. The orientation of the suture closure remains controversial, some surgeons preferring a vertical closure and others a horizontal orientation. There are very few data to support one technique over the other and probably the direction resulting in the least tension is the most appropriate. If the defect is large (> 6 cm
2
), or occurs within a divarification of the recti, the hernia should be repaired with prosthetic mesh. This technique is described later in the chapter when considering incisional hernias. The technique applied to intermediate-sized hernias is controversial and suture or mesh techniques are both currently deemed acceptable. Laparoscopic repair of epigastric hernias
9
was first described in 1993 and the technique has grown in popularity. The author prefers an open technique under local anaesthetic whenever possible for smaller hernias (defect < 2 cm), suture or mesh depending on the quality of the tissues, and the laparoscopic approach for larger, multiple, recurrent hernias, or hernias in the obese. At laparoscopic repair, it is important to take down the falciform ligament and remove any pre-peritoneal fat above the linea alba, otherwise the ‘hernia’ may still be palpable following the alleged repair.
Complication rates are low and most are the usual complications associated with abdominal wall incisions (haematoma, infection). There are very few data on recurrence rates, historical series reporting rates around 7%.
10
In perhaps 50% of patients, however, the recurrence probably represents the persistence of a second hernia or area of weakness overlooked at the initial procedure. The laparoscopic technique avoids this problem because all fascial defects are visible laparoscopically if adequate dissection is carried out.
There are several distinct types of hernia that occur around the umbilicus: congenital (omphalocele), infantile, para-umbilical and adult umbilical hernias.
A congenital umbilical hernia occurs when the abdominal viscera herniate into the tissue of the umbilical cord. Normally, the gut returns to the abdominal cavity at 10 weeks of gestation. If this fails to occur, normal rotation and fixation of the intestine are prevented, the umbilicus is absent and a funnel-shaped defect in the abdominal wall is present through which viscera protrude into the umbilical cord. The abdominal wall defect may vary in size from no larger than an umbilical stump to a defect that appears to involve the entire abdominal wall. Congenital umbilical hernia occurs in 1 in 5000 births and is associated with other serious congenital anomalies.
Congenital umbilical hernia may be diagnosed in utero or at birth. On ultrasound examination, foetal abdominal wall defects are not subtle and may be visualised as early as 15 weeks of gestation. The management is surgical correction and one of the most important contributors to the morbidity and mortality of isolated abdominal wall defects is the delay between delivery and appropriate surgical repair. Antenatal knowledge of the existence of a congenital hernia can allow for the birth of the child at a tertiary care institution with the appropriate neonatal and paediatric surgical expertise (see also
Chapter 12
).
Surgical correction should only be undertaken in specialised centres. If the diagnosis is made prenatally, the mother should be transferred to such a centre for delivery. If the diagnosis only becomes apparent at birth, the baby should be kept warm and hydrated, and the sac handled with care to avoid rupture or twisting of the sac. The sac should be wrapped in moist sterile gauze and covered with impervious plastic sheeting or aluminium foil. Mother and baby should then be transferred as soon as feasible to a tertiary centre for further management.
Infantile umbilical hernias occur when the umbilical vessels fail to fuse with the urachal remnant and umbilical ring. It presents with a protrusion of the umbilicus, usually at the superior margin of the ring. The infantile hernia, as opposed to the congenital type, is always covered by skin. It is the third most common surgical disorder in children, occurring in approximately one in five live births.
Clinically, the commonest presenting ‘symptom’ is the cosmetic appearance, the hernia resulting in a cone-like protrusion of the umbilicus that bulges every time the child cries or strains. Infantile umbilical hernias rarely enlarge over time and 90% disappear by the time the child is 2 years of age, although they are unlikely to close spontaneously if they persist to the age of 5 years.
11
Spontaneous resolution of umbilical hernias appears to be directly influenced by the size of the umbilical ring. If, at the age of 3 months, the hernia has a fascial ring of < 0.5 cm, 96% heal spontaneously within 2 years. Defects that have a fascial diameter > 1.5 cm are unlikely to heal spontaneously. Complications of umbilical hernias are rare, occurring in approximately 5%, and include strangulation of the omentum, strangulation of the intestine and evisceration.
Management of the infant with an umbilical hernia is expectant. The majority will resolve spontaneously without surgical correction. The indications for surgery in children less than 2 years of age are the development of complications or tenderness over the site of the hernia. There is no consensus on the appropriate timing of herniorrhaphy in older children but generally repair is performed before school/nursery to avoid the child becoming self-conscious of the umbilical protrusion.
Operative details:
Elective repair of infantile umbilical hernia is performed on an outpatient basis under general anaesthesia. A curvilinear incision is made within a skin fold on the inferior aspect of the hernia. The sac is then encircled by blunt dissection. If there is any concern regarding the contents of the sac, the sac should be opened on its caudal aspect, as abdominal contents usually adhere to the fundus of the sac. Once dealt with appropriately, the contents should be reduced and the incision continued to the cephalic aspect of the sac. If the sac is empty, the fundus may simply be disconnected from the umbilicus and reduced intact. Repair is by simple fascial apposition using horizontal mattress sutures of absorbable material. While the Mayo (‘vest-over-pants’) technique of umbilical hernioplasty is frequently taught, there is no evidence that the results are any better than simple apposition of the fascial edges. The umbilicus is refashioned by leaving a small button of the fundus of the sac attached to the inner surface of the cicatrix and tacking it down to the area of fascial repair.
Complications of umbilical hernioplasty are rare, but include seroma or haematoma formation and infection. Recurrence is possible if large defects are closed under tension or if an associated para-umbilical hernia is overlooked.
Para-umbilical hernias are acquired hernias and occur in all age groups. They occur secondary to disruption of the linea alba and generally occur above the umbilical cicatrix. Aetiological factors include stretching of the abdominal wall by obesity, multiple pregnancy and ascites. Para-umbilical hernias are more common in patients over the age of 35 years and are five times more common in females.
Clinically, para-umbilical hernias are frequently symptomatic. Patients complain of intermittent abdominal pain (possibly caused by dragging on the fat and peritoneum of the falciform ligament) and, when the hernial sac contains bowel, colic resulting from intermittent intestinal obstruction. The hernia tends to progress over time and intertrigo and necrosis of the skin may occur in patients with large dependent hernias. Such symptoms are a good indication for surgery.
It is important to distinguish para-umbilical hernias from true umbilical defects as the latter may resolve spontaneously in the young, whereas the former require surgical correction. Umbilical hernias classically produce a symmetric bulge with the protrusion directly under the umbilicus. This is in contrast to para-umbilical hernias, where about half the fundus of the sac is covered by the umbilicus and the remainder is covered by the skin of the abdomen directly above or below the umbilicus(
Fig. 4.3
). Para-umbilical hernias do not resolve spontaneously and have a high incidence of incarceration and strangulation; therefore, surgical repair is nearly always indicated.
Figure 4.3
Clinical photograph of a para-umbilical hernia. Note the swelling of the right groin of an associated right inguinal hernia – a common finding consistent with a generalised collagen disorder.
Operative details:
For solitary hernias separated from the umbilicus, a transverse incision over the hernia produces the best exposure. In patients with a para-umbilical and umbilical hernia, a midline incision may provide better access. Similarly, if multiple fascial defects are present or there is concern about the integrity of visceral contents of the sac, a vertical incision may be better employed. If the defect simply contains pre-peritoneal fat, this may be reduced. In patients with strangulated or ischaemic pre-peritoneal fat, it is best excised. If there is a sac present, it should be dissected free from the fascial edges, opened and the contents examined. Once the contents have been dealt with appropriately, they may be reduced and redundant sac excised. There is no requirement to close the peritoneum but some authors recommend transfixing the neck of the sac once the contents have been reduced. Repair is performed by fascial apposition either transversely or longitudinally, depending on the defect and the direction of least tension. As this is an acquired defect, non-absorbable sutures are recommended. Indeed, the author usually creates a pre-peritoneal pocket, inserting a 5 cm × 5 cm square (minimum size – bigger if necessary) mesh and closing the fascia over this. The classic Mayo approach
12
overlaps the edges, but there has never been any demonstration that the bursting strength of the wound is improved by imbrications and may actually be impaired to a degree proportional to the amount of overlapping and tension. For larger para-umbilical hernias, with a neck size > 3 cm (or smaller hernias in an obese patient), it is the author's preference to repair these laparoscopically and very large hernias with a neck size > 8 cm by an open sublay technique (described later).
The overlying umbilical skin need not be excised unless it is macerated or infected, although the cosmetic appearance is often enhanced by judicious removal of excess skin and subcutaneous fat. All patients should be warned that it might be necessary to excise the umbilicus. If a new umbilicus is to be created, care should be taken as recurrences may occur at the point on the linea alba where the new umbilicus is fixed to the fascia.
Complications include the development of seromas, haematomas and infection. Sealed suction drains may be employed in the retromuscular and subcutaneous planes to avoid the development of large seromas. In addition to local problems, these patients may have respiratory and cardiovascular complications.
Umbilical hernias in adults represent a spectrum of conditions from the partially unfolded cicatrix to huge dependent sacs. The umbilicus may become partially unfolded in patients with acute abdominal distension. Persistent elevation of intra-abdominal pressure eventually results in the umbilical cicatrix giving way and the development of an umbilical hernia. Although uncommon, causes include ascites from cirrhosis, congestive cardiac failure or nephrosis. Patients undergoing peritoneal dialysis also have a high incidence of these hernias. Management should be non-operative where possible, as the majority of these patients have serious underlying pathology. Operative repair is not indicated unless the hernia incarcerates or becomes extremely large and the overlying skin is thinned down to such an extent that spontaneous rupture is possible.
Umbilical hernias in adults do not represent persistence of infantile hernias but are indirect herniations through an umbilical canal, which is bordered by umbilical fascia posteriorly, the linea alba anteriorly and the medial edges of the two rectus sheaths on each side. They have a tendency to incarcerate and strangulate and do not resolve spontaneously. Umbilical hernias in adults have a high morbidity and mortality. Over 90% occur in females and almost all patients are obese and multiparous.
The clinical presentation, management and complications of adult umbilical hernia are very similar to those of para-umbilical hernia, as described above.