The new science of back pain

12 minute read

The way we treat back pain seems seriously messed up. Most treatments don’t work or aren’t supported by the science.

Severe back pain, mostly unremembered thanks to heavy-duty painkillers, cost Liam Mannix’s father the best years of his life. Then he had surgery that experts said shouldn’t have worked, surgery described by one as ‘criminal’.

I’ve suffered from back pain all my life, although it’s never been as bad as my Dad’s. After seeing what Dad went through, I was committed to finding a way to make sure it never would be. But as I dug into the science of back pain, interviewing patients and doctors and scientific experts, a very strange story started to emerge. Back pain, I discovered, is an epidemic of extraordinary scale. About four million Australians will have it every year; about 175 000 will be hospitalised. And the problem seems to be getting worse, not better – despite, or possibly because of, the enormous sums of money we spend on it.

And the way we treat it seems to be seriously messed up. Most treatments simply don’t work, or aren’t supported by the science. Many of them are extortionately expensive and pose real risks, yet because of vested interests we keep giving them to people.

Intradiscal electrothermal annuloplasty (IDET)

Intradiscal electrothermal annuloplasty is one in a long line of treatments designed to treat degenerative discs – all which seem to ignore the evidence that (a) people can have blackened, gnarled discs and not be in any pain, and (b) even if a disc is causing pain, we don’t have any good test to work out which one it is.

Anyway. IDET, as it is known, inserts a catheter into a ‘painful’ disc, and then slowly heats it to 90 degrees Celsius. It will remain this hot for about four minutes. This, we are told, is a ‘non-invasive therapy’.

IDET was introduced in the year 2000 by back pain specialists who were inspired by cauterisation, where surgeons burn some tissue to essentially seal a wound. Could the same thing be done to a damaged disc? they wondered. In experiments on animals they showed that heat could shrink the disc, a bit like what happens when you burn cling wrap.

At first, results looked incredibly promising. The first study reported a success rate of around 75 per cent. Even better, the trial reported zero side effects. Zero!

Clinical trial results that are too good to be true should raise big red flags – especially in things as hard to treat as back pain. The studies were essentially reporting that you could use a hot needle to burn someone’s disc without anything going wrong – not just that, but that their new trick could cure chronic back pain, something no one else was having much success with. But instead of raising red flags, the paper was accepted for publication in the field’s leading journal Spine.

Everyone became very excited, especially as other surgeons started replicating the results in their own practices. ‘It’s like the disc has a facelift. We get rid of the wrinkles and cracks so that it works better,’ one London spine surgeon told the Daily Mail back in 2001 when the procedure was growing popular.

That first paper does not mention, as far as I can tell, that the inventors stood to gain financially from their device. Other IDET papers obliquely noted ‘benefits in some form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript’.

Nortin Hadler was an editorial board member of Spine at the time. ‘I had no idea of the extent of the commercial involvement,’ he writes. The inventors founded a company. By 2001, it was turning over $21 million annually from IDET products. It was later sold for $310 million. The inventors were publishing results, incredibly good ones, about a device sold by a company one of them cofounded.

‘If this was a pharmaceutical, it would never have been licensed on the basis of such information,’ writes Hadler in Stabbed in the Back.

Enter Christopher Cain. ‘If it sounds too good to be true,’ he tells me, ‘it usually is.’ Cain is now a professor in the spine division of the University of Colorado, Denver, but back in 2005 he was working as a spine surgeon in the department of orthopaedics at the Royal Adelaide Hospital. He and his colleagues did not buy the evidence the inventors were selling. ‘They were fairly anecdotal. They weren’t good scientific studies,’ he says.

This scepticism caused quite a fuss, given IDET was becoming very popular. It was marketed as non-invasive, it seemed safe, and it was relatively cheap, so its use was taking off. ‘Medicine is a business,’ says Cain. ‘It’s a business of recruiting patients for treatments to generate revenue for hospitals and doctors. Sometimes it’s hard to differentiate the financial benefit to the providers from the benefit to the patient in terms of relieving symptoms.’

The inventors met the scepticism head-on. You don’t believe us? they said. OK – let’s do a proper study. With funding from their company, Cain and his colleagues put together a very careful experiment. Patients with back pain of exactly the type the inventors said IDET would treat were randomised into two groups. One group received the procedure. The other simply had the catheter inserted but not turned on. Because of the anaesthetic used and the careful set-up in the operating room, neither group was able to tell whether they received the treatment.

When the results came in, the improvement shown in earlier studies disappeared. If there was any improvement, it was so slim as to be attributable to statistical noise – and sometimes patients got worse. The inventors weren’t happy. They pushed the surgeons to change the experiment parameters, look at patients with less damage to their discs. ‘But even when we looked at those patients, there was still no difference,’ says Cain. ‘It did not work at all. There is really very little benefit beyond the placebo effect.’

Then there were the side effects. Cain calls it a low-risk procedure, but things do go wrong. Sometimes the catheter got stuck in the disc and broke off – requiring extensive surgery to remove. Sometimes the catheter damaged a nerve. Sometimes the punctured, burnt disc developed an infection. Sometimes you got a cerebral spinal fluid leak. The technique seems to weaken the disc, increasing the chances of a hernia. One study reported complication rates as high as 15 per cent – much higher than the zero reported in the first study.

IDET is meant to shrink the disc like burning cling wrap. But sometimes it blows up the disc to giant proportions. That happened to a 29-year-old soldier, who turned up at a medical centre after spending a year and a half fighting chronic back pain that radiated into his left thigh. He’d tried everything: chiropractors, opioids, injections. The surgeons decided to apply IDET to two discs that were showing small signs of deterioration. The procedure went perfectly, the surgeons reported. But the soldier came back a few days later – the pain was now much worse than before. The surgeons opted to bump up his opioid doses. Several weeks later, he was back again, eventually convincing the doctors to MRI his spine. The disc had responded to IDET by blowing up, a huge mushroom of dead and damaged material pushing into the delicate spinal cord. The patient – now hooked on fentanyl – was booked in for a spinal fusion; the surgeons spent much of the procedure picking apart the ballooned disc. Perhaps the worst complication I have come across: in rare cases, the heat can get high enough to cause bone surrounding the disc to die, eventually leading to accelerated disc degeneration and bone collapse.

‘If a surgeon proposes it – and there are plenty of places that still offer it – you should ask “Would you undergo this procedure yourself?”’ says Cain. ‘I would not have it done. I would not recommend anyone I care about have it done.’

Radiofrequency denervation

Radiofrequency denervation has a lot of similarities to IDET – although, while IDET has somewhat fallen by the wayside, many enthusiasts of ‘nerve burning’ remain. A needle is inserted at the supposed site of pain – often the facet joints, sometimes the discs themselves – where it is pushed up against nerves thought to be transmitting the pain. The needle is then heated with a burst of electricity or radiation. The heat kills the nerve and, theoretically, ends the pain.

As far as scientists can tell, it also does not work.

Denervation has an incredible history. It starts in 1914, when a young Vincent Nesfield of the Indian Medical Service was stationed on the front lines of World War I in Mesopotamia. Soldiers kept coming to Nesfield’s infirmary with ‘trench back’, back pain caused after a trench collapsed on them. Nesfield decided the problem was a hooked nerve somehow tangled in a muscle or tendon, and determined to cut it free.

He took a thin, long, curved scalpel and made cuts down both sides of the soldiers’ spines, moving the blade back and forth vertically. The treatment was an apparent success, though Nesfield wouldn’t get much of a chance to exploit it – he was soon deregistered by medical authorities for trying to hawk a miracle injection he called ‘Vitalexin’. But by then he’d already passed on the trick to British surgeon William Skyrme Rees. Rees wouldn’t last as a doctor either – he was drummed out after penning an official report claiming British hospitals were the dirtiest in the world. Rees took the trip many ostracised people do: to the Antipodes. He hung out a shingle in the tiny New South Wales town of Tocumwal and started slicing into the spines of farmers with back pain.

Rees penned a letter to an academic journal announcing that he had cured 998 of the first 1000 patients he’d seen – causing a huge stir nationally and internationally. Better, Rees had come to the attention of the then federal health minister Dr Doug Everingham, who was so enamoured of the doctor’s treatment that he installed an extremely high government rebate for the procedure.

Rees, now famous, moved to Macquarie Street, started giving lectures, and became a media darling, now claiming Nesfield’s spine-slicing as his own invention. It wasn’t until 1977 that other surgeons seriously studied what Rees was doing and discovered that, far from slicing a nerve, the scalpel was slicing into muscle. If the muscle was spasming, the cut likely relieved some of the spasm (Rees completely rejected that claim).

That takes us up to 1972, when Rees had a fortuitous meeting with C Norman Shealy, an American neurosurgeon who was fresh off inventing the implantable spinal cord stimulator. Shealy tested Rees’s technique and found it led to too much bleeding for his taste; he replaced the scalpel with electrodes, and radiofrequency denervation was born. Shealy reported a 90 per cent success rate, and back pain doctors once again had a new toy to play with. The procedure took off in popularity and has never stopped.

In a story that will now be familiar to you, it took until 2001 – 25 years after the procedure had been pioneered – for good quality placebo-controlled evidence to be published. Richard Leclaire and his team inserted a catheter into the spine of 70 patients, but only half of the group of 70 patients got a hot catheter. The results were straightforward. After four weeks there were no differences in pain, disability, flexibility or strength between the two groups. Whether the nerve was burnt or not seemed to make no difference. A Cochrane review in 2015 concluded there was no high quality evidence showing the procedure worked at all for chronic low back pain.

The failure of the procedure is borne out in repeat rates; about a third of people who have one ablation will have another within three years, suggesting that if they do provide relief, it is temporary at best.

‘How many more waves of therapeutic zeal must we witness – waves of spine-surgical inventiveness that provide nothing more than testimony to hubris and often greed – before we design a way to abort the next?’ asks Nortin Hadler in Stabbed in the Back.

The problem is how expensive it is to run a proper clinical trial of a new surgical intervention. Why would a company or a treatment pioneer spend millions of dollars to potentially discover their money-making procedure does not work? As patients, this leaves us exposed to medical treatments that are often tested far too late. ‘This is a big problem in medicine,’ says Dr Ralph Mobbs. ‘And I don’t know the answer.’

Spine surgeon Ian Harris is far less charitable. ‘There’s no burden of proof on surgeons,’ he tells me. ‘In surgery, we think up things to do, and we continue to do them until someone goes out of their way to go and do a study to find out if it works or not. There’s no requirement to do the study.’

After writing about all the damage done by inventive procedures given to tens of thousands of people before ever being properly tested, I’m inclined to agree with him. By now, you may be getting sick of this rogues’ gallery of failed treatments and harmed patients. But pay particular attention to this one. I think nerve burning is a clue, a signal among the wreckage of failed back pain treatments that tells us that something strange is going on here.

Nerve burning cuts the transmissions between sensory nerve and brain. If that sensory nerve is in a painful area, the pain should stop, right? But it doesn’t. The pain keeps on and on, despite the cable being severed.

‘It assumes there’s a direct, one-to-one relationship between pain and sensory nerve information,’ says Dr Matthew Bagg, a back pain researcher at NeuRA (Neuroscience Research Australia) who has studied the therapy. ‘And we know that’s just not the case.’

This is an edited extract from Back Up by Liam Mannix, NewSouth Publishing, RRP $34.99. 

Liam Mannix is a multi-award-winning national science reporter for The Age and the Sydney Morning Herald, as well as Nine’s other stable of mastheads.

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