Shocking: The new video of an Australian chiropractor cracking a screaming newborn's spine.

Chiropractor Ian Rossborough’s latest YouTube video stars his own newborn daughter, Isla. In one month, it’s had half a million views.

As an obviously doting father, Dr Ian, as he’s known, explains that Isla is having her first chiropractic checkup. They’re on the sofa in his Melbourne living room.

Isla, he says, had a natural birth at home and had been very healthy but had now, at one week old, developed conjunctivitis.

So he would check her spine.

He notes that she has an upper cervical “nerve irritation”. He places two fingers carefully under the base of her skull, at the side, against the top of her neck.  There’s a small but obvious sidewise jolt of Isla’s head, which doesn’t seem to bother her.

Afterwards we see Isla sleeping.

In an interview with Radio National’s Background Briefing, Ian Rossborough explained what he was doing.

“I noticed that there was starting to collect some conjunctivitis in both eyes… Using the spine as a way of maintaining health, I thought, let’s check the spine and see if there’s a problem there.

“As it turned out, I felt something in the upper cervical region which we commonly see if the person has that dysfunction in their spine.”

That particular dysfunction, he said, was associated with conjunctivitis – “along with oh, maybe 100 other potential symptoms”.

The problem, he said, was with Isla’s C1 – the first vertebra in the spine.

"Basically the one the head sits on. It's a very important vertebra from the point of view of chiropractic, because it is a ring of bone... And that's the first entry into the body which the spinal cord goes through. So we do find that there's a lot of dysfunction associated with spinal subluxation of that C1."

The way chiropractors use the term subluxation, as a spinal misalignment which is not necessarily detectable on xrays, is not accepted by medical science. Nor is ‘spinal misalignment’. Nor ‘nerve irritation’, in any sense other than the physical, such as when a disc compresses a nerve and causes pain.

Many chiropractors say their spinal manipulations can affect nerves which in turn benefit a range of conditions. They have recently been warned against making these claims, by their regulator, the Chiropractic Board. But the board seems unable to keep up with a flourishing industry, one stream of which focuses on babies and children.

Many chiropractors who work with babies say their spines can be misaligned during the birth process. This is not supported by medical evidence. They recommend early treatment, and that has included ‘unofficial’ treatments by chiropractors who have snuck into hospitals to manipulate newborns at the mother’s request.

Dr Paul Bauert, the head of paediatrics at Royal Darwin Hospital, and vice-president of the Australian Paediatric Society, watched the Isla video, and was dismayed.

"Oh look... I honestly found that quite unbelievable. I think this person believes what he is doing is right, and that's an additional worry that he is using pseudoscience and believing it," Dr Bauert said.

In another video a four-day-old baby’s back is manipulated, with a loud crack. Dr Bauert says it is far too risky to be doing that.

"A lot of the bone in neonates and young children is not actually ossified, it's not hard, it's soft cartilage. And you really do run the risk of damaging the cartilage, and later on in life causing  problems of skeletal development as the bones ossify.

"If they ossify abnormally you may in fact end up with problems like Sherman's disease or scoliosis."

Chiropractics remains a relatively under-researched field, so long term outcomes are not sufficiently documented.

Critics of chiropractics say if patients are happy with their treatments, particularly with non-muscular skeletal conditions, it may well be the placebo effect, or the effect of a caring practitioner, or the power of belief of the patient.

Chiropractors undoubtedly have devoted followings.

Ian Rossborough says while they might know about him from his YouTube videos, patients are happy simply because of his  diagnosis and treatment.

"Like there's no way that I would have 600 people a week, flying from other countries all over the world, a waiting list of 200-300 people, a five month waiting list for new patients, and four other practitioners in the practice.... People trying 10, 20, 30 years of other therapies... If placebo and state of mind or emotion was going to fix those people, there is one million other opportunities for that to happen."

Listen to the full story here and follow Background Briefing on Twitter here. Ann Arnold is also on Twitter here.