What is Lumbar Puncture
The term lumbar puncture is more commonly known as a spinal tap. Lumbar puncture is a procedure that takes a sample of cerebrospinal fluid.
Reasons for a Lumbar Puncture Procedure
The reasons for having a lumbar puncture procedure may be to perform analysis of cells or to relieve intracranial pressure. Intracranial pressure is pressure exerted by the cranium (skull) on brain tissue, cerebrospinal fluid (the liquid substance that flows around the brain to act as a cushion or to protect it) and the brain’s blood volume. Many factors can cause intracranial pressure ranging from exercising to coughing and breathing.
Patients who may be demonstrating signs of meningitis will likely undergo lumbar puncture or similarly, infants who have an unexplained fever, but are too young to show typical or common signs of meningitis will undergo lumbar puncture.
Another cause to have lumbar puncture may be to administer medication into the cerebrospinal fluid. The two most common reasons for injection of medication is for spinal anesthesia or chemotherapy.
Are there Risks or Side Effects Involved with Lumbar Puncture
As with all medical procedures, there are risks involved. One of the most common complications or side effect is for the patient to suffer from a headache that is usually accompanied with nausea. Depending on the severity of the headache, it has been noted that a patient may find relief with an intravenous caffeine injection. A persistent headache that occurs when the patient moves to a sitting position may be due to a leak of fluid from the lumbar puncture. Generally, a longer period of bedrest may treat the leak, however some patients may require a procedure that involves injecting the patient’s blood where the leak occurs. In so doing, the blood forms a clot and seals the leak.
Another risk may be temporary paralysis in the leg that typically lasts during the length of the procedure.
While serious complications during a lumbar puncture procedure are rare, they can occur. These may include spinal bleeding, or trauma to the spinal cord or spinal nerve roots. If there is trauma to these areas of the spine, the result can range from loss of sensation or weakness to permanent paralysis, though it should be noted that this is extremely rare.
Who Should Avoid Lumbar Puncture Procedures
Any patients who demonstrate signs or have been diagnosed or receive confirmation that they have any epidural or topical infection at the puncture site should not have this procedure. Similarly, for patients who may be at risk of infection in that area due to skin conditions, this procedure should not be performed.
Lumbar Puncture Procedure, Preparation and Aftercare
A lumbar puncture procedure’s first step is to instruct the patient to lie on their left side, legs brought up and in to the fetal position and the head/neck tucked in so the chin is pointing to the chest. The patient is then covered with a sterilized covering. The opening is positioned at the puncture site. This area is then cleansed and sterilized and a local anesthetic is administered to minimize pain.
A thin, hollow needle is then inserted between two vertebrae in the lumbar region and is slowly inserted toward the spine. At that point, a clear flow of cerebrospinal fluid will fill the needle. The doctor will usually take multiple vials of fluid for analysis. Depending on the level and flow of fluid, the needle may need to be removed and repositioned.
In advance of the lumbar puncture, patients are not asked to cease performing their normal day to day activities, though it is recommended that the patient relax before the procedure. The reason for this is to have the muscles relaxed to allow for the needle to easily pass through the tissue to the spinal canal.
The aftercare of lumbar puncture is relatively simple. It involves the patient lying down up to six hours after the procedure and to help prevent lumbar puncture headaches, the patient is instructed to drink fluids. The doctor will cover the lumbar puncture site with a bandage and it is usually recommended that the patient leave this bandage on for 24 hours.