Consequently, many causes of disastrous residual pain are caused by inappropriate surgery. The most popular operations include: laminectomy, in which a disc and nearby bone are removed to give the nerve branching off the central spinal cord more space to move without getting trapped or compressed by the spine; and fusion, in which one vertebrae is surgically joined to another to minimize what has been diagnosed as too much movement between them. After the operation, this segment of the spine will be unable to move.

Henry La Rocca, clinical professor of orthopaedic surgery at Tulane University in New Orleans, examining six studies of back operations found that removing discs only relieved back pain in about half of all patients (The Lumbar Spine, as above). He quotes a study in 1980 of 105 cases of failed spinal surgery, primarily disc removal. In 68 per cent of the patients, they concluded, surgery wasn't indicated (Spine, 1980; 5: 87-94). Three out of four studies comparing operating with or without lumbar (lower back) spinal fusion surgery found no advantage for fusion and that complications, including chronic pain, were common (JAMA, 19 August 1992).

US orthopaedic surgeon Dr Charles Burton of the Institute for Low Back Care in Minneapolis, Minnesota, in analyzing failure of surgery on the spine over 10 years, quotes from a June 1981 interinstitutional orthopaedic and neurosurgical study of 'failed-back surgery syndrome'. In more than half of all such cases, the diagnosis missed or the surgery itself caused a condition called 'lateral spinal stenosis', or narrowing of a portion of the spine causing compression of the spinal cord or an abnormally tight fit.

Finally, postsurgical scarring ('epidural fibrosis') can itself cause failed surgery and chronic pain. La Rocca also found substantial evidence that surgeons cause nerve root injury as the nerve is being separated from herniated disc material, causing scarring and therefore long-term pain and pressure on the nerve. 'Damage to the dura or the cauda equina [membranes covering the spinal cord] from poor surgical technique yielding possibly catastrophic results completes the list,' he writes.

This is precisely what happened to Sarah of Woking. Her back problems developed after a hysterectomy, so she consented to further surgery on her spine. The delicate layers of the spinal cord (meninges) became inflamed, and then thickened. This thickened membrane now presses constantly on her spine, incapacitating her with unbearable pain.

At Gordon Waddell's clinic in Glasgow in Scotland, '60 per cent believe or have been told that they have a disc prolapse, although only 11 per cent show any evidence of nerve root involvement,' he says. Gordon Waddell and others conclude that if there is a specific problem correctly identified, such as a spinal deformity or fracture or disc herniation, then surgery can help, but not for simple relief of unspecified back pain (Spine, 1986; 11: 712-19).

Many hundreds of thousands of cases of chronic, debilitating back pain were - and still are - caused by myelograms used purely for diagnosis. This diagnostic tool involves the use a contrast medium or dye. This is injected into the canal space and trickles into and around all the discs and nerve roots in the back, which is then x-rayed. Mounting evidence shows that a good percentage of myelogram patients will develop a condition called arachnoiditis, causing permanent, unrelenting pain and rendering many virtually unable to move.