In June 2003 the National Institute for Clinical Excellence (NICE) issued guidance on the management of head injuries in the UK. The key features of this guidance were that the indications for computed tomography (CT) should be widened and that CT should replace skull radiography in the investigation of minor head injury. Reaction among my colleagues to these guidelines ranged from despair to disbelief.

Despair because this is yet another piece of central guidance that has been issued with little regard for its operational or financial consequences.

For example, an initial assessment of the impact of this guidance in this hospital indicates that an additional 725 CT scans will be required each year, of which about half will be performed outside office hours. Given that there is a national shortage of radiologists, is it a good idea to promote a policy that demands so much additional radiologist input?

Data issued by the National Radiological Protection Board also indicate that a CT head scan exposes a person to 100 chest radiographs’ worth of radiation,¹ and the NRPB has an ongoing campaign to reduce the public’s exposure to medical radiation. How does this square with a policy that would dramatically increase the use of head CT, particularly affecting the brains of young children?

The implementation of these guidelines will also result in patients waiting long periods in A&E for a scan. How will this help A&E departments seeking to achieve the four hour throughput target set by the government? The guidance also encourages patients with minor head injury to dial 999 for an ambulance. What impact will this have on our already hard pressed ambulance services? So much for “joined up” thinking by the NICE advisory panel.

Predictably the NICE guidance does not come with any additional funding, and in this hospital alone the estimated cost of implementation is £30 000. Multiply that by 500 to get some idea of the total cost to the health service.

There is also disbelief. Firstly, because the guidance seems disproportionate to the problem. On a Sunday afternoon most A&E departments are full of children who have fallen a metre or so and banged their head, or who have vomited after a head injury. How many of these children are going to have a CT scan, and how many will need a general anaesthetic to allow this to be performed?

Furthermore, in minor head injury one of the most common abnormalities found on CT is skull fracture.² Given that such fractures are usually visible on skull radiography is there really no future for this inexpensive and low radiation investigation?

The guidance also suggests that normal CT will save beds by avoiding admission. What is the evidence for this, and will A&E departments really send home badly concussed patients just because their CT scan is normal?

All these doubts call into question the scientific basis, and the authorship, of the NICE guidance. Unfortunately the written guidelines issued by NICE do not quote the articles upon which this advice is based. Surely we have moved on from the days when “experts” hand down instructions without providing the supportive evidence. Furthermore, many of the key recommendations are based on level 5 “evidence”—that is, expert opinion only. As to the authorship of the guidance, it would appear that very few of the NICE experts manage minor head injuries on a day to day basis. Perhaps this explains the underlying impracticability of much of their advice.

It is therefore apparent that an objective scientific analysis is required of the NICE guidelines for head injury. Much of the evidence upon which this guidance is based comes from tertiary trauma centres in North America. The case mix at these units will be skewed towards more serious injury, and is likely to be quite different to the sort of head injuries seen in most UK A&E departments. There is a parallel here with trauma centres. In the 1980s, publications from the US seemed to suggest that trauma centres should be established in the UK. But when a formal trial was carried out here no appreciable benefit was demonstrated.³

If the scientific evidence concerning CT minor head injuries can be shown to be applicable to this side of the Atlantic, then a proper cost/benefit analysis should be carried out to assess the probable impact of this guidance in UK hospitals. This analysis should include the radiation risks⁴ and the practical difficulties of CT, particularly in children. Such an analysis could save the health service a lot of money and prevent excessive exposure to radiation.

Ultimately this issue calls into question whether it is either helpful or even possible for a group of “experts” to dictate medical practice. Patient’s interests are best served if their doctor questions received wisdom, and demand compelling scientific evidence before implementing new forms of health care.