Lumbar Puncture

Complications of lumbar puncture include brain herniation, spinal headache, nerve root injury, infection, and formation of an epidermoid tumor. 

 

Many of the complications of lumbar drain placement are common to all procedures where lumbar puncture is performed:

Table: Neurosurgical Risks & Complications

 

Complications particular to lumbar puncture include:

 

 

herniation

A pressure gradient favors movement of tissue from one compartment one neighboring. 

When it occurs, which is very rarely, herniation is apparent within a few minutes of a lumbar puncture.  

Herniation following lumbar puncture

 

spinal headache

A hematoma in the posterior fossa

Patients complain of headache sometimes during the procedure but more typically in the first few minutes after the procedure when they try to sit of stand up. 

One of the functions of CSF surrounding the brain is to cushion the brain from injury against the skull.  Without CSF the brain sits directly on the dura which is heavily supplied by sensory fibers.  The pressure of the brain on the pain fibers in the dura is thought to be the pathophysiologic basis of headache following lumbar puncture with removal of CSF.

If the lumbar puncture needle makes a big enough hole in the dura there may be a small defect left after the needle has been withdrawn.   A slow leak through a small dural hole may result in symptoms of dural pressure (headache) only several hours after lumbar puncture.   

The cerebrospinal fluid that was taken out through the lumbar puncture needle inserted into your back, into the spinal canal, and through the dura mater left a hole in dura when it was taken out. Cerebrospinal fluid is under higher pressure than the epidural space (the space around the dura mater) and therefore cerebrospinal fluid moves out of the subarachnoid space (name of the cerebrospinal fluid space just inside the dura mater) into the epidural space and beyond. The subarachnoid space is continuous around the spinal cord and up and over the brain. Once the CSF around the spinal cord has completely leaked out the CSF from around the brain will be mobilized and leak out too.

The length of time for the hole to close is shorter the smaller the hole in the dura. Usually after a few hours patients can get up without significant headache. Most clinics keep patients laying down for up to 4 hours after a lumbar puncture.

After 2-3 days of conservative therapy something more invasive may be required:

1. blood patch — blood is withdrawn from a vein (just like taking blood for a lab test). Lumbar puncture is again performed except this time the needle is passed only as far as the epidural space. The blood is then injected into the epidural space where it coagulates over the hole in the dura forming a “patch” that stops further leakage of CSF.

2. surgical closure — never heard of this being necessary but it could be done … blood patch works very well.

Be persistent with your physician — spinal headaches are very unpleasant and there is no reason for you to suffer any longer.

posterior fossa hematoma following posterior fossa decompression

posterior fossa hematoma following posterior fossa decompression

 Normally the CSF around the brain acts as a cushion: it keeps the brain from resting directly on the dura. The dura has many pain receptor fibers that are sensitive generators of head pain. As long as the CSF continues to leak there will be an inadequate cushion, the brain will press on the dura, and the headaches will persist.

The size of the hole left by the spinal needle depends on the size (guage) of the needle: usually the smallest possible needle is used to avoid the complication of “spinal headache” but sometimes even a small hole is enough to allow a large amount of CSF to leak.

The treatment for spinal headaches that are not gone after 8 hours:

1. Bedrest. Patients are usually most comfortable with the head of the bed flat (or even with the feet elevated higher than the head [so-called “Trendelenberg” position]).

2. Oral analgesics. Tylenol, non-steroidals (Motrin, Ibuprofen, Naprosyn, aspirin, Celebrex, etc. — in those who can take them). More severe pain may require opioid medications like codeine, Vicodin, Darvocet, etc.

 

 

 

root injury

Lumbar puncture is usually done between the L4 and L5 vertebral levels.  Where the needle enters the dura there are roots of the cauda equina .  The chances of putting a needle into one of the roots suspended in the thecal sac are about as good as spearing cooked soft spaghetti floating in water with the lumbar puncture needle (or the prong of a fork)..

 

 

epidermoid

An epidermoid is a benign tumor made up of the same kind of cells that make up the skin.

Epidermoid tumor following lumbar puncture takes years to form.

Epidermoid tumor following lumbar puncture is caused by transplantation of cells from the skin to the intradural space.

Epidermoid tumor following lumbar puncture can reach a size sufficient to press on the cauda equina causing neurologic deficit.

 

 

infection

An infection can result from puncture of the skin 

An infection following lumbar puncture usually does not present for several days.