Nick Seddon's intriguing description of the innovative cataract surgery being delivered by SalaUna in Mexico is the latest radical healthcare model from a low or middle income country to be held up as an example to the NHS.

In India, Aravind Eye Care and the cardiac surgery offered by Narayana Hrudayalaya in Bangalore have been recognised as similarly mould breaking. They have in common a desire to extend healthcare to uninsured and low-income patients by driving down the cost of treatment, and have developed new methods of delivery characterised by high volumes and novel uses of staff.

This has sometimes meant taking on the vested interests of the medical profession, and Seddon's description of SalaUna suggests that power lies with the managers of the business, who use contracts, incentives, data and dismissal as tools to shape the behaviour of clinicians.

Faced with examples of this kind, it is very easy to follow Seddon's logic: the NHS suffers from inertia, which is undeniable in some areas. And it would follow that bringing in new entrants to the market and giving them autonomy over staff terms and conditions will banish this inertia and innovation will flow.

But two observations can be made here. The first is that the NHS has already hosted some experiments with private sector companies developing and refining high-volume surgical procedures. Independent sector treatment centres, which have steadily grown in number since Labour introduced them in 2003, have proved popular with patients, as their increasing volumes of surgery have shown.

They have produced some different ways of working; in some cases, managers have been able to run a tighter ship with their clinicians than has been possible in the NHS. But as a whole, they have yet to demonstrate that they are much more efficient or high quality than their NHS counterparts.

The second observation is that there may only be a limited number of discrete, surgical procedures that lend themselves to this sort of innovation.

Most hospital care is complex and there can be considerable ambiguity about the right course of treatment. In the US, Atul Gawande recently explored whether large, chain-style ownership of hospitals and physician groups might lead to a greater evidence-based standardisation of treatment procedures and drive out some of the over-utilisation that has proved so costly for the US health care system.

The example of the US should serve as a counterweight to those who argue that new entrants will always lead to innovation.

In the US, benevolent innovation by the private sector (be it for profit or not for profit) to improve quality and reduce costs is still very rare when compared with the relentless drive of hospitals and physicians to make money and expand, regardless of underlying health care needs or the reality of limited family, employer or state budgets. So much so, that the government is now taking a leading role in enabling and spreading innovation with its Medicare and Medicaid Innovation centre.

Many are watching with interest to see if any of the good ideas that are emerging can be scaled up across hospital and physician groups across the US. But it is worth noting that the private sector can also suffer from considerable inertia when faced with the need to contain costs.

Ruth Thorlby is a senior fellow in health policy at the Nuffield Trust

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