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  • How to Do a Lumbar Puncture – Instructions From a Practising Neurologist

    Introduction
    Even today the word lumbar puncture still strikes fear in patients and practitioners. Like all fear, education will alleviate it! I’ve now done hundreds of LPs, teach about LPs and write LP guidelines. Here’s how I go about it. The information here would be very useful when counselling your patients prior to the test. Any postgraduate physician in training would be expected to have a detailed knowledge of how to do an LP, https://www.mississippimigrainecenter.com/neurologist-southaven-ms/ and it is a core skill for emergency medicine and neurology.

    Before you do an LP, make sure you have observed several successful and unsuccessful procedures. Make yourself aware of the anatomy of the lumbar spine and spinal canal, and the layers that your needle will traverse. An LP will be a lot easier in a calm environment e.g. side room, treatment room, day-case theatre/OR. I strongly advise that you have with you a nurse or nursing auxiliary who has assisted at many LPs before.

    Equipment
    An LP is usually performed on a hospital bed, or treatment couch or procedure table. The room should be well lit, warm and private. You will need, anti-septic (chlorhexidine or iodine-based), sterile drapes, sterile gloves. You will need a hypodermic needle and 5 ml syringe to draw up local anaesthetic, and another hypodermic needle to inject the local anaesthetic. You need a spinal needle (will discuss choice of needle later), and a manometer to measure opening pressure. Specimen containers are required – usually 4 are needed, and a fluoride oxalate tube if glucose is being measured in CSF. Blood bottles and venepuncture equipment for paired blood glucose, protein and serum oligoclonal bands are also needed. Most hospitals will already have pre-packed trays to which you need to add your own manometer. Pre-packed spinal amaesthesia trays usually have very fine (25 or 27G)atraumatic needles. These fine atraumatic needles may not be suitable for diagnostic or therapeutic LP, you will need a 22G atraumatic needle if you are hoping to measure opening pressure. Alternatively you can use an ordinary sterile dressing pack and add your own choice of LP needle and manometer.

    Choice of needle
    There has been debate for years about use of atraumatic needles versus the classic bevelled tip needle. The difficulty with atraumatic needles is that the aperture in the needle is small and the needle is of fine bore making pressure recording (arguably) unreliable and sample collection slow. A bevelled needle will give a more reliable pressure reading and in some cases you actually want to create a dural tear – such as therapeutic LP in Idiopathic Intracranial Hypertension. There is consensus that atraumatic needles do reduce the incidence of post-LP headache. If you can obtain a 22G atraumatic needle, you should use that. There is a technique described where oblique insertion of a traditional bevelled needle can create a self-sealing hole – this is not widely practised but makes a lot of sense. Whichever needle you choose, you should be comfortable with its handling to keep patient discomfort to a minimum.