Where is spinal puncture made

The clarity and color of the fluid are also checked and it is tested to see whether bacteria, viruses, or abnormal cells are present. Excess CSF may also be removed in people who have an overproduction or decreased absorption of the fluid. A lumbar puncture procedure may be helpful in diagnosing many diseases and disorders, including:. An inflammation of the membrane covering the brain and spinal cord.

The inflammation is usually the result of a viral, bacterial, or fungal infection. An inflammation of the brain that is usually caused by a virus. Bleeding in the area between the brain and the tissues that cover it subarachnoid space. Reye syndrome. A sometimes fatal disease that causes severe problems with the brain and other organs. Although the exact cause of the disease is not known, it has been linked to giving aspirin to children. It is now advised not to give aspirin to children during illnesses, unless prescribed by your child's healthcare provider.

A stage of syphilis during which the bacteria invades the central nervous system. A disorder in which the body's immune system attacks part of the nervous system. Demyelinating diseases. Diseases that attack the protective coating that surrounds certain nerve fibers - for example, multiple sclerosis or acute demyelination polyneuropathy.

Headaches of unknown cause. After evaluation and head imaging if necessary, a lumbar puncture may be done to diagnose certain inflammatory conditions that can result in a headache. Pseudotumor cerebri also called idiopathic intracranial hypertension, or IIH.

In this condition,pressure within the subarachnoid space is elevated for reasons that are not clear. A lumbar puncture is only done in this condition after evaluation and head imaging. Normal pressure hydrocephalus. A rare condition affecting mainly older people in which there is a triad of loss of urinary control, memory problems, and an unsteady gait.

A lumbar puncture is done to see if the pressure of the CSF is elevated or not. In addition, a lumbar puncture may be used to measure the pressure of the CSF. The healthcare provider uses a special tube called a manometer to measure s the pressure during a lumbar puncture.

Finally, a lumbar puncture may be done to inject medicine directly into the spinal cord. These include:. Your healthcare provider may have other reasons to recommend a lumbar puncture. Because this procedure involves the spinal cord and brain, the following complications may occur:. There may be other risks depending on your specific medical condition.

Be sure to discuss any concerns with your healthcare provider before the procedure. I f you are having a lumbar puncture at Johns Hopkins Hospital or Bayview Medical Center, a neuroradiologist or radiology nurse will contact you by phone two or three days prior to your lumbar puncture to discuss the procedure and answer any questions you may have.

Please inform the neuroradiology physician if:. Other options should be discussed with you and your doctor. A gown will be provided for you. However, the procedure may also be done while you remain in your clothes from home.

Cerebrospinal fluid is derived from blood plasma. It is secreted from capillaries within the choroid plexus, which are extensions of the vascular pia mater that dip down into the roof of the third and fourth ventricles Blows, The fluid fills the entire ventricular system inside the brain - the two lateral ventricles and the third and fourth ventricles - as well as the subarachnoid space and the central canal of the spinal cord.

The flow is caused by the action of cilia extending from cells that line these spaces. These provide a beating motion that sweeps the fluid along. The rate of CSF production must be met by an equal rate of CSF reabsorption to prevent any build-up of fluid in the brain and spinal cord. The fluid is reabsorbed by arachnoid villi which return it to the venous blood before it leaves the head Blows, These values, and the concentration of potassium, calcium and bicarbonate in CSF, are lower than the equivalent values found in blood plasma.

CSF has a pH of about 7. The total volume of CSF is ml at any given time. This volume is replaced three to four times a day at roughly eight-hourly intervals. About ml of CSF is produced every day. Normal CSF pressure measured with a manometer is mm of water.

These may occur when a space occupying lesion SOL develops. The differential in production and absorption of CSF, along with changes in blood flow through the brain, help to prevent any major increase in intracranial pressure as an SOL grows in size.

Such compensation can be effective only for a limited time, depending on the rate of growth of the SOL;. This is usually a safe procedure undertaken to acquire a sample of CSF for analysis, and is also sometimes done to measure CSF pressure or to introduce drugs into the CSF, a procedure known as intrathecal injection.

The insertion of a needle under local anaesthetic requires careful positioning to prevent injury to the spinal cord. Since the spinal cord ends as a solid structure around the level of the second lumbar vertebra L2 the insertion of a needle must be below this point, usually between L3 and L4 Fig 2. The spinal cord continues below L2 down into the sacrum as many separate strands of nerve pathways, the cordae equina, bathed in CSF. Putting a needle into the spaces between the strands to collect fluid is much safer than taking the risk of hitting the solid cord higher up the spine.

The spinal vertebrae are held together by ligaments. Those penetrated in a lumbar puncture are the interspinous ligaments which bind adjacent spinous processes together and the ligamentum flavum which binds adjacent vertebral laminae together and, in so doing, lines the posterior wall of the spinal canal. Lumbar puncture must be carried out as a sterile procedure, with full aseptic precautions to prevent the introduction of outside organisms into the spinal canal and the contamination of the specimens collected.

The patient must be either:. The interspace is selected after palpation of the spinous processes at each lumbar level. Once the area for needle insertion has been ascertained, the examiner puts on a mask and sterile gloves — this decreases the risk of infection. The skin is then cleansed with alcohol and usually an iodine based disinfectant and the area is draped with a sterile cloth.

The lumbar puncture needle is typically a 20 — 22 gauge needle and it is inserted into the target area and slowly advanced.

The bevel of the needle is maintained in a horizontal position with the flat portion of the bevel pointing up and it should be parralel to the direction of the dural fibers. Once a subarachnoid space has been reached, a manometer can be attached to the needle to record the opening pressure.

Fluid is then usually obtained for collection. Fifteen millilitres of CSF is usually sufficient for a sample. The fluid is then taken and may be analysed for a number of parameters according to the clinical presentation including:. The minor risks and complications associated with a lumbar puncture include backache, post lumbar puncture headache , radicular pain and numbness.

Major complications that rarely occur include infection, haemorrhage, damage to the spinal cord or nerve roots and herniation of cerebral tissue in patients with pre-existing increased intracranial pressure.

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