THE VERMIFORM appendix – to give it its full title – is a narrow worm-like protrusion of the gut at a point where the small intestine joins the large bowel.
Originally thought to be a vestigial organ with no known use, the appendix was somewhat rehabilitated two years ago when researchers proposed it did, after all, have a defined immune system function: as a storage area for “good” bacteria until they were needed to repopulate the gut after a period of illness such as a bout of severe diarrhoea.
A blind pouch, the appendix wins no prizes for good design. At its opening into the gut it is very narrow and is easily blocked. This leads to an initial inflammation of the appendix (appendicitis). Pressure builds up within, bacterial infection sets in, the appendix swells up and it eventually becomes gangrenous as its blood supply is cut off.
If left untreated, it then perforates, leading to peritonitis – the spread of pus and infection throughout the abdomen and pelvis.
A newly published study of the appendix through the ages has concluded that Charles Darwin, who said the organ was simply an evolutionary remnant, was wrong. Researchers from Duke University Medical Center in North Carolina said the appendix has been around for at least 80 million years.
And using the latest approaches to evolutionary biology, they have found that more than 70 per cent of primates and rodents contain species with an appendix. Dr William Parker, assistant professor of surgical sciences at Duke University, says appendicitis is not the result of a faulty appendix but is the product of improved sanitation.
“This change left our immune systems with too little work and too much time on their hands – a recipe for trouble.”
Despite the latest theory, the incidence of acute appendicitis has halved in the past 20 years, for reasons that remain unclear. This decline has been mirrored by changes in the approach to managing the condition.
Back in 1889, Charles McBurney presented a classic report to the New York Surgical Society on the importance of early operative intervention for acute appendicitis. He described the point of maximal tenderness in the abdomen which helped to define an accurate diagnosis and, five years later, he devised a particular surgical incision which today bears his name.
The diagnosis of acute appendicitis can be quite difficult to make – not all show the classic findings of tenderness over the lower right side of the abdomen, accompanied by nausea and vomiting.
A test called “rebound tenderness” – in which the doctor places his hand over the left side of the tummy, presses down and lifts away suddenly with the patient experiencing worse pain “on the rebound” – is helpful. The doctor may also perform a rectal examination, which will reveal tenderness on the right side as his finger presses against the inflamed appendix.
Probably the single greatest advance in surgical practice in the past two decades has been the introduction of the laparoscope. It has significantly changed the management of acute appendicitis.
Like a miniature telescope, the laparoscope is inserted through the belly button, allowing the surgeon to directly view the appendix. If the appendix is inflamed, it can be removed, using instruments passed through the laparoscope. If it looks normal, unnecessary surgery is avoided and other causes for the symptoms sought.
A systematic review of trials of laparoscopic versus open appendectomy has confirmed the advantage of the minimally invasive option. Laparoscopic appendectomy halved the number of wound infections and reduced post-operative pain, the length of hospital stay and the time taken to return to work.
Its principal disadvantage is a threefold increase in the number of post-operative abscesses which occur.
The laparoscopic approach comes into its own when there is a diagnostic dilemma. It is especially useful in young women in whom the difficulty in making an accurate diagnosis is often greatest, and it has the advantage of being able to detect an ovarian cyst and other gynaecological causes of abdominal pain.
Meanwhile, the Duke researchers hope to develop a method of preventing appendicitis by challenging our immune systems in a similar manner to the way they were challenged in the Stone Age.
A diet of grubs and berries, anyone?