I've seen the most grateful patients I've ever seen in my life

Brian Freeman, Queen's Medical Centre

Patients also have to have gone through physiotherapy, exercise regimes and pain relief treatments before they will be considered for IDET.

The procedure was developed in the US, and is only carried out at around six centres in the UK.

Doctors are still carrying out independent studies to support IDET's marketers' claims.

But Mr Brian Freeman, a spinal surgeon at Nottingham's Queen's Medical Centre, who performs IDET, said that he had seen many patients who had improved after the procedure.

Mr Freeman, who learnt the technique while studying in Australia at the Royal Adelaide Hospital said: "I thought IDET had enormous potential - and I've seen some dramatic improvements."

Scan needed

He said it was suitable for people whose movement was impaired, who may only be able to sit for 10 to 15 minutes before it became too painful.

Mr Freeman added: "The standard patient that would come to see me would be 45, with disabling lower back pain, who had tried all the conventional therapies."

Patients have to undergo a scan and an exploratory investigation to see how badly their discs are affected.

IDET is only suitable for people with one or two discs affected.

A hollow needle is guided into the affected disc, and an electrothermal catheter, a heating wire, passed through it into the disc.

Most of us are waiting for a trial. It's very difficult to evaluate its effectiveness

Philip Sel British Association of Spinal Surgeons

This is heated up to 90�C and tissue temperature goes up to 65 - 70�C.

That is enough to destroy the nerve endings which are sending the pain messages to the brain.

Only the part of the needle which is in the disc is not insulated, so the patient's skin does not get burnt.

The procedure, carried out under local anaesthetic, takes less than an hour and does not need an overnight hospital stay.

The patient then has to wear a corset for the next six weeks and do nothing before starting an intensive course of physiotherapy.

'Kick-start'

Some doctors have suggested it is the physiotherapy rather than the procedure itself which makes the difference.

Philip Sel, secretary of the British Association of Spinal Surgeons, told BBC News Online: "Most of us are waiting for a trial. It's very difficult to evaluate its effectiveness."

But one patient said IDET had given her a "kick-start" to enable her to do the much-needed physio which she had been in too much pain to do before.

The alternative for patients is two-stage spinal surgery where each stage takes two hours.

Patients are then in hospital for a week, and it can take up to 18 months to recover.

The surgery can cost up to �3,000, whereas the needles used in IDET cost around �800 each.

Mr Freeman said: "If we are able to really define who will benefit from IDET, it could completely revolutionise the treatment of back-pain."

He estimated it could help 30% of patients he sees.

"I've seen the most grateful patients I've ever seen in my life."