THE SUNDAY TELEGRAPH – 14 January 1996
What a piece of work is the human body
THE HUMAN body in its prime is a masterpiece of elegant design where even its apparently insignificant features prove to be indispensable. Without tears to keep the cornea moist, the immensely complex visual system would be useless. Without earwax we would be prone to recurrent ear infections. There are perhaps two faulty features: the appendix serves no function other than to give budding young surgeons the opportunity to practise their skills in removing it when it becomes inflamed, while the female pelvis is generally too small for the large head of the human foetus.
These faults aside, it is very difficult to see how the body could be improved on – as indeed a group of experts concluded. James Drife, an obstetrician suggested that the human race would be better off if women ovulated only once a year. "An annual mating season would release humans from their morbid year-round obsession with sex," he said. There were some useful suggestions that perhaps our nerves should have the capacity to regenerate completely – as they do in flatworms – and that our teeth should constantly renew themselves throughout life. But the general view expressed was that of biologist Stephen Jay Gould: "There is nothing to fix so we should leave well alone."
Thus, each aspect of the human body seems precisely suited to fulfil its purpose, and an appreciation of this miracle of design is essential when some part does break down and needs fixing.
Recently this has been demonstrated quite dramatically in major advances in the treatment of two conditions – sinusitis and cleft palate. The purpose of the sinuses is to humidify inspired air on its way down to the lungs while filtering out bacteria, viruses and other potentially noxious substances. Consequently, sinuses themselves are vulnerable to infection, which, if persistent, leads to the state of chronic sinusitis in which they become filled with a sort of infected glue that drips down the back of the throat, while the head feels heavy and bunged up – all very unpleasant.
The standard operation for the condition has been to make a hole at the base of the sinuses so they can drain by gravity, while periodically washing them out to get rid of the accumulated gunge. This sounds plausible enough, but the results have never been very satisfactory and sinusitis has a rather dismal reputation of being "difficult to treat".
However, this situation has now been transformed because of a much better appreciation of the ingenious design of the sinuses. The inspired air enters the sinuses through an opening in the back of the nose and passes over the mucociliary membrane which lines them. This is a combination of mucus glands, whose secretions trap bacteria and pollutants, and millions of minute hairs, or cilia, whose rhythmic movements extrude them back out through the opening into the nasal cavity. If this mechanism is damaged, the infected secretions cannot be eliminated, resulting in chronic sinusitis.
Thus, rather than making a hole at the base of the sinuses to allow the secretions to drain, it would be much more logical to widen the opening from the nose into the sinuses, thus ensuring the free flow of air, facilitating the elimination of noxious substances and permitting the damaged membrane to recover. And, indeed, just such a procedure – known as functional endoscopic sinus surgery, in which a thin tube is passed up the nose and the entry to the sinuses is widened – has proved to be much a more effective treatment.
It is a similar story in children with cleft palate, who usually have a repair operation in the first week after birth, when the skin and muscle on either side of the cleft is sewn together. Initially there is a good aesthetic result, but as the child grows other physical anomalies become apparent: the nose and the centre of the face flattens, the jaw protrudes and the teeth develop poorly, and these in turn require further corrective operations.
It used to be thought that these anomalies were caused by the same genetic abnormality that had given rise to the cleft palate initially, but an appreciation of the way the face grows shows that this is not the case. The crucial point is that the facial tissues must all grow in harmony; that is, the skin and muscle, the teeth and the gums must all interact while moulding the shape of the bony skeleton underneath.
The complications of cleft palate repair, therefore, are not due to the original defect but rather to a failure of the initial operation to fully restore the anatomical relations of the tissues on each side of the cleft in such a way as to permit them to grow harmoniously together. Working on this assumption, some British surgeons have switched to performing a much more extensive and thorough repair of the cleft palate with much better results.
The main characteristic of both these operations is how they flow with the tide of Nature, releasing the potential within the affected body parts to heal themselves and function normally. The technical skills of the surgeons are certainly impressive, but the credit for their success belongs to Nature alone.
Copyright: Telegraph Group Ltd