What is a lumbar puncture?
A lumbar puncture is a procedure where a doctor uses a small needle between the bones of the lower spine (vertebrae) to take a sample of cerebrospinal fluid (CSF) from the spinal canal.
CSF is a special fluid that protects the brain and spinal cord from injury.
Lumbar punctures are usually done at the bedside by a doctor. When it is difficult to do the procedure at the bedside, it can be done using image guidance by a neuro-interventional radiologist. How it is done will be decided after discussion between the referring physician and the interventional radiologist.
Why is lumbar puncture done?
Lumbar puncture may be done to:
- collect CSF to send to the lab for tests
- measure the pressure of your child's CSF
- inject cancer-fighting medications (chemotherapy) or other medications such as antibiotics or anaesthesia
Risks of a lumbar puncture for your child
Lumbar punctures are considered low-risk procedures. The risk may increase depending on your child's condition, age and health.
The risks of a lumbar puncture include:
- infection introduced into CSF
- headache: After the procedure, children sometimes get a bad headache. This happens because the hole where the spinal needle went in stays open and CSF can leak out, causing a headache. In most cases, the hole closes on its own and the headache goes away in few days.
- leakage at the site of the needle insertion
- bleeding
- change in sensation, numbness or weakness in the lower limbs and back
- difficulty peeing or having unexpected accidents after the procedure
- nausea and vomiting
Giving consent before the procedure
Before the procedure, the interventional radiologist will go over how and why the procedure is done, as well as the potential benefits and risks. They will also discuss what will be done to reduce these risks, and will help you weigh any benefits against the risks. It is important that you understand all of the potential risks and benefits of the lumbar puncture and that all of your questions are answered. If you agree to the procedure, you can give consent for treatment by signing the consent form. A parent or legal guardian must sign the consent form for young children. The procedure will not be done unless you give your consent.
How to prepare your child for the procedure
Before any treatment, it is important to talk to your child about what will happen. When talking to your child, use words they can understand. Let your child know that medicines will be given to make them feel comfortable during the procedure.
Children feel less anxious and scared when they know what to expect. Children also feel less worried when they see their parents are calm and supportive.
Food, drink and medicines before the procedure
- Your child's stomach must be empty before sedation or general anaesthetic.
- If your child has special needs during fasting, talk to your doctor to make a plan.
- Your child can take their regular morning medicine with a sip of water two hours before the procedure.
- Medicines such as acetylsalicylic acid (ASA), naproxen or ibuprofen, warfarin, or enoxaparin may increase the risk of bleeding. Do not give these to your child before the procedure unless they have been cleared first by their doctor and the neuro-interventional radiologist. The doctor will also test your child's blood to make sure that their blood clots normally.
On the day of the procedure
Arrive at the hospital two hours before the planned time of your child's procedure. Once you are checked in, your child will be dressed in a hospital gown, weighed and assessed by a nurse. Some freezing cream or a patch may be put on your child's lower back where the lumbar puncture will be. You will also be able to speak to the interventional radiologist who will be doing the procedure and the nurse or anaesthetist who will be giving your child medication to make them comfortable for the lumbar puncture.
During the lumbar puncture, you will be asked to wait in the surgical waiting room.
Your child will have medicine for pain
It is important that your child is as comfortable as possible for the procedure. They may be given local anaesthesia, sedation or general anaesthesia. The type of medicine that your child will have for the procedure will depend on your child's condition.
How a lumbar puncture is done
If your child is having sedation or general anaesthesia during the lumbar puncture, it will be given by a nurse or anaesthetist when they are brought into the procedure room.
Your child will lie on their side with their knees up and their back curved out, so the spaces between the vertebrae are as wide as possible. This makes it easier for the doctor to insert the needle. The interventional radiologist uses X-rays or ultrasound to identify the part of the spine where the needle will be inserted.
A spinal needle is thin and the length varies depending on the size of your child. Your child will not need any stitches. They will have a small bandage over the puncture area that can be removed after 24 hours.
After the lumbar puncture
Once the lumbar puncture is complete, your child will be moved to the recovery area. The interventional radiologist will talk to you about the details of the procedure. As soon as your child starts to wake up, a nurse will come and get you. Your child will be monitored by a nurse for one hour. Your child will need to lay flat for at least one hour after the procedure, even if they wake up earlier. Lying flat reduces the chance of CSF leaking out and headaches. If there are no concerns your child will be ready to go home about one hour after the procedure.
Pain after the lumbar puncture
Your child may have some discomfort in their back immediately after the lumbar puncture. If this happens, your child will be given pain medicine. At home, you can give your child acetaminophen if needed or medications prescribed by their doctor.
Results
The results of the lumbar puncture will be sent to the referring doctor. You should arrange a follow-up appointment with them to discuss the results.
Going home
Most children can have a lumbar puncture and go home the same day. If your child's doctor has arranged this, your child will be ready to go home about one hour after the procedure.
For more details on how to care for your child after a lumbar puncture, see Lumbar puncture: Caring for your child at home after the procedure.
If the procedure was performed in the IGT department
If you have any concerns in the first 48 hours, call the IGT clinic at (416) 813- 7654 ext. 201804 and speak to the IGT clinic nurse during working hours or leave a non-urgent message with the IGT clinic nurse.
If you have concerns and it is after working hours, see your family doctor or go to the nearest Emergency Department or call The Hospital for Sick Children switchboard at (416) 813-7500 and ask them to page your referring doctor or the interventional radiology fellow on call.
If the procedure was performed by another service
If you have any concerns during the 48 hours after the procedure, you can contact the doctor who performed the procedure or a clinic nurse at ________________________________.
If you have concerns and it is after working hours, see your family doctor or go to the nearest Emergency Department or call the Hospital for Sick Children switchboard at (416) 813-7500 and ask them to page your doctor.
For more information on fasting see Eating and drinking before surgery.
For more information on preparing your child for their procedure see Coming for surgery.