Spinal Tap (cont.)
During the Procedure
Most spinal taps can be completed within 10-15 minutes.
You are asked to lie on your side with your legs and hips bent (flexed) up toward your chest and your neck slightly bent forward. This position is often called the fetal position. (Some doctors place you in a seated position, where you lean forward and rest your arms on a tray or back of a chair. This is an acceptable alternative position.)
The doctor always uses sterile technique including wearing sterile gloves.
The spinal tap is performed using sterile technique, meaning that everything used is sterilized to minimize any risk of infection.
The doctor next identifies the correct place to insert the needle by orienting herself toward landmarks on your body. Frequently, the doctor does this by feeling the top of the pelvis bone (on your side). This area corresponds with the fourth and fifth lumbar space where the needle is inserted.
Once the area is identified, it is prepared in a sterile fashion, which usually involves applying a liquid cleansing solution and drapes.
A numbing medication (lidocaine) is injected first into your skin and then into the deeper tissues of your lower back to numb the area completely. This injection causes some minor discomfort, which is usually brief and has been described as a burning sensation.
You should inform the doctor at any time if you feel pain when the procedure is being performed.
The needle is then inserted in your lower back, usually at the third and fourth lumbar or fourth and fifth lumbar level. The needle passes between the two vertebrae to enter the space where the fluid is contained. Placing you in the fetal position allows the vertebral spaces to open more widely to make needle passage easier.
Occasionally, the doctor may measure the pressure within the fluid containing area. This does not change the procedure nor does it affect the results.
The fluid is then allowed to collect into a series of three or four vials that are then sent to the lab for evaluation.
The fluid collects passively, meaning it is allowed to drip out into each vial at its own pace. This step can take several minutes for a full specimen collection.
After the fluid is collected, the needle is removed and a bandage or small dressing is placed over the area.
Medically Reviewed by a Doctor on 11/13/2014
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