Lumbar Puncture

To keep discomfort from an LP to a minimum, it is important to be fully aware of the range of experiences an LP may bring.  Having performed many LPs in his career, he would vouch that many patients will have virtually no pain, except for the sting of local anaesthetic injection.  “There is no doubt that some people are very distressed by their LP.  Usually this is becasue it is not possible to find a pathway for the needle which avoids contact with the bones of the spine.  This can be a particular problem in people who are very overweight, and we all know that the trends in obesity will make LPs more difficult for more patients in the coming years”

If there is a problem with the needle path or trajectory, why don’t doctors use x-rays to guide their needles?  One reason is that the majority of LPs are done easily and it is perhaps unreasonable to expose people to x-rays without good cause. However, a recent review by Dr Michael Murphy Dr Arun Nagdev of the American College of Emergency Physicians outline the value of using ultrasound  to guide needles in difficult cases.  This technique may be useful in children or obese patients, or people who have previously had back surgery.  At present x-ray guided LPs are rarely used except in the most difficult cases.  Ultrasound may become more widely used, but this will involve provision of new equipment to financially stretched hospitals and additional training for doctors.

In the next 5 years I expect that image guided LP with ultrasound will become more commonplace - I’ve yet to use it in my own practice, but can see the advantages and hope to try it very soon.  Better patient information is also needed.  We have to move away from telling people that there will be a ‘wee scratch’ and make sure that before LP our patients are properly informed. Using best available technology they should then go on to have a technically competent procedure.

There is more information, being added to weekly at www.lumbarpuncture.net, and I am indebted to the IIH forum www.iihsupport.org for personal descriptions of LP.