Another complication usually among the elderly or those with a heart condition can be triggered by the infusion of carbon dioxide into the stomach, necessary to allow the laparoscope to "see". Sudden irregular heart beat was reported in 17 per cent of patients when carbon dioxide was introduced, according to one British survey. Another study of 49 patients showed that a third suffered a slowing heart rate when the gas was used (Aust NZ J Obstet Gyn 1993; 31:171-173).

In the US, some states do not allow surgeons to perform minimally invasive surgery unless they have been properly trained. In others, as in the UK, surgeons with little or no experience can carry out the procedure. The Society of American Gastrointestinal Endoscopic Surgeons has suggested that surgeons should first carry out procedures on animals before being allowed to operate on people.

Not surprisingly, a study by the University of Iowa showed that complications during and after surgery reduced if the surgeon concerned had been trained in the procedure (JAMA, 8 December, 1993). They suggest that training needs to include a post residency course and "on the job" experience with other surgeons.

But is it safe, even in experienced hands? While the emphasis has been on the surgeon and his lack of experience, a case in Australia also showed up the inadequacy of some of the microtechnology used. One charge of negligence has been filed because the surgeon had not realized that the field of vision through the laparoscope is limited (The Lancet, 11 September 1993). Because the surgeon could not see, a needle entered the patient's colon during the procedure.

If punctures are the most common complications, the spread of disease is potentially the most dangerous. Open surgery in treating cancer carries a high risk of spreading diseased cells to healthy ones, but that risk increases when using keyhole surgery. This is because the surgeon does not have full visibility or control and also because diseased organs and cells have to be squeezed through small incisions, thus increasing the likelihood of diseased cells dropping off and "planting" into healthy organs. This problem was highlighted recently in Cardiff, Wales, where two women who had keyhole surgery on their gall bladders both died from cancer. As the surgeons pulled the malignant tissue through the small hole in the wall of the abdomen, cancer cells broke off and planted themselves in the abdomen.

Does it help for speedier recovery? One of the first major randomized studies comparing removal of the appendix with laparoscopic techniques and conventional, open appendectomy showed there was no difference in postoperative pain and recovery among patients of either procedure.

This is a devastating finding which kicks away one of the platforms on which laparoscopic procedures have been championed.

The study, by the Prince of Wales Hospital in Hong Kong, was based on a comparison of 70 patients who underwent open appendectomy and 70 on whom laparoscopic procedures were performed. Each study group was similar in age, sex ratio and duration of symptoms.

There were no major complications in either group, although 20 per cent of the laparoscopic group had to convert to an open operation.

The research team, headed by Professor J Tate, found no difference between the groups in terms of severity of pain, the need for painkilling drugs, time in reintroducing normal diet, or hospital stay. Similar numbers from both group attended follow up examinations three weeks after surgery, and similar proportions 79 per cent of laparoscopic patients, and 74 per cent of open surgery patients had returned to work (The Lancet, 11 September 1993).