and poisoning of the kidneys, particularly among diabetics. In one study, of 319 patients with abnormal kidney function after being given ‘high osmolality contrast agents’, nearly one in 10 required kidney dialysis.73
Contrast agents like iopamidol, used for urographs and angiographs, have also been linked with pulmonary oedema (fluid in the lungs).74 Barium, used for barium enemas, has been known to remain in the bowel and harden. In a patient with with a weakened bowel from diverticulitis, ulcerative colitis or Crohn’s disease, the impacted material could cause the colon to split open.
Many hundreds of thousands of cases of chronic, debilitating back pain have been caused by spinal x-rays, called myelograms. This diagnostic tool involves the use of a contrast medium or dye injected into the canal space and trickled into and around all the discs and nerve roots in the back, which is then x-rayed. Mounting evidence shows that a number of myelogram patients will develop a condition called arachnoiditis, causing permanent, unrelenting pain and rendering many virtually unable to move.
Arachnoiditis is a little-understood condition in which the middle membrane protecting the spinal cord becomes scarred. Nerves atrophy and become enmeshed in dense scar tissue, which presses constantly on the spine. US orthopaedic surgeon Dr Charles Burton of the Institute for Low Back Care in Minneapolis, Minnesota, one of the few doctors to make a study of lumbar sacral adhesive arachnoiditis (LSAA), estimates that it accounts for 11 per cent of patients with ‘failed back surgery syndrome’– where surgery has left them worse off than before.
Although LSAA results from a number of different causes, in Dr Burton’s view it is mainly caused by the introduction of foreign substances into the human sub-arachnoid space. The foreign body most often identified in victims, he says, is iophendylate (known as Myodil in the UK; Pantopaque in the US), the oil-based dye used for myelograms. In LSAA, he says, iophendylate is often found in a cyst within the scar tissue mass.
An estimated one million people worldwide suffer from arachnoiditis caused by this dye, and even this figure could be conservative. Until the 1980s, nearly half a million myelograms were being performed in the US every year.
This is exactly what happened to Brian from Massachusetts. In 1980, after a staphylococcus blood infection causing paralysis, fever and pain, Brian had to undergo back surgery. Before his operation, a myelogram was performed on him, which left residual dye in Brian’s coccyx.
In 1993, after spraining his back, he developed severe muscle spasticity, which caused pain in his legs and lower back. Each night now, the pain forces him out of bed every one or two hours. An MRI scan and x-ray finally revealed that Brian had arachnoiditis and that the myelogram he’d had left residual dye in his coccyx. ‘Eighteen months, and several doctors later, with muscle relaxants, physical therapy, epidermal injections, chiropractic and even seizure drugs like Dilantin, nothing seems to work,’ he says.
Pantopaque was introduced in the US in 1944 after the medical profession was convinced that it was safe. This was despite animal studies showing that Pantopaque caused arachnoiditis (the Swedes banned the product from use in humans in 1948).75 Even though the product was discontinued by Glaxo with the onset of water-based dyes and imaging techniques, iophendylate continued to be used around the world until supplies ran out, and many back specialists continued to maintain that the dye was safe.
At the time, the US Food and Drug Administration and the British government also made no moves to ban oil-based myelograms. ‘Despite the fact that iophendylate was identified as being causally related to the production of arachnoiditis from the time of its introduction, its use in the US has never been restricted by industry, government or the medical profession,’ says Dr Charles Burton.76
It took patients with myelogram-induced LSAA bringing legal suits against the manufacturers before anyone else took notice. In the UK, the Arachnoiditis Society has some 1,000 members, and a class action suit was taken against Glaxo. After detailed negotiations, Glaxo reached a settlement with the 426 plaintiffs of £7 million, without admission of liability.
The water-based dyes now being used instead are not without risk. One woman being investigated for sciatic pain (back-caused leg pain) with iopamidol (Niopam 200), a water-soluble contrast medium, was immediately rendered paraplegic,77 as was another middle-aged woman given a myelogram with itohexol (Omnipaque), another water-soluble dye.78 Dr Burton says that some new mediums have caused such pain that the x-rays have had to be performed under general anaesthesia. ‘The medical profession has not yet succeeded in finding a benign, effective myelographic medium,’ he says.79
BONE SCANS
Besides looking for broken bones, x-rays are now being used to screen for osteoporosis. That might be a good idea – if we had a test that could be relied upon to deliver an accurate result. The problem is, as many medical experts agree, that even the latest techniques in bone scanning should be interpreted with caution, since changes in bone mass may not signify anything.80
The instruments are imprecise, multiple measurements may be wrong, even the assumptions upon which we scan bone are open to question – for example, the very notion that bones have a density that can be measured or that we can treat it and effectively reverse bone loss.
The latest souped-up bone scan is the ‘dual energy x-ray absorptiometry’ or DEXA – a fancy sort of x-ray. Again, you are injected with a radioactive liquid beforehand, then asked to lie flat on a table while you are scanned for between a half-hour to an hour or even more if a full three-dimensional shot is required. Measurements are usually taken from the spine, hip, spine, heel and forearm.
But an accurate reading in this technique can easily be knocked off. ‘A walk around the room causes the measurement to change by up to 6 per cent (at the hip), which corresponds to six years of bone lost at the usual rate,’ says Susan M. Ott, associate professor in the Division of Metabolism, University of Washington in Seattle.81 Poor machine quality-control and a high percentage of operator error also throw off results.
The favoured technique, measuring many different areas of the body at the same time – one shot of the top of the leg produces five separate measurements, for instance – also increases the risk of a false-positive reading.
‘Apparently dramatic changes can be taken as indicating improvement or dramatic bone loss but may simply be due to the precision of the measurement and poor repositioning technique,’ wrote David M. Reid, a rheumatologist at City Hospital in Aberdeen, Scotland, and his colleagues.82
Studies show that DEXA tests are not necessarily very accurate. In one study, the scans failed to detect osteonecrosis in one-sixth of confirmed cases.83 Extremes in weight (under- or overweight), age (over 60) and arthritis can throw off the result of a test. In fact, the entire exercise of measuring bone mass may be useless, because bone mass doesn’t necessarily have anything to do with bone strength. For instance, fluoride causes bone mass to increase dramatically, but decreases its strength. This is why elderly populations in highly fluoridated communities show an increase in osteoporosis. Similarly, some drugs may increase bone mass by 5 per cent, but because bone structure has been damaged, it isn’t strengthened with the drug. New research shows that only half the people considered to be at most danger from a fracture because of their reduced bone density will actually suffer one.84
It’s important to understand that bone in healthy individuals is a dynamic entity, constantly undergoing interior remodelling.