Causes

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>> Spinal CSF Leak Causes

1. Iatrogenic – caused by a medical procedure
a. Post lumbar puncture CSF leak (often known as Post Dural Puncture Headache = PDPH)
This is the most common cause of a spinal CSF leak. The lumbar dura is intentionally punctured for various diagnostic and therapeutic reasons. An example would be a diagnostic lumbar puncture (LP) for a patient thought to have meningitis, to analyze and culture the cerebrospinal fluid. Another would be a lumbar puncture for injection of contrast for a type of spinal imaging known as myelography. A common therapeutic reason would be spinal anesthesia. Most often these holes heal over quickly, but in some cases, they do not. We know that there
is a lower risk of PDPH when the procedure is performed by more experienced clinicians, when smaller needles are used and when a less traumatic type of lumbar puncture (LP) needle (pencil-point vs sharp) is used.
b. Dural tears may occur inadvertently at the time of epidural injections. (epidural space is in spinal canal outside of dura and spinal cord)
c. They may occur at the time of spinal or other surgery.
d. CSF shunt over-drainage may cause intracranial hypotension.
e. Chiropractic or other spinal manipulation has been reported as another cause.

2. Traumatic – caused as a result of an injury.
Traumatic leaks have been reported in association with brachial plexus injuries, spinal injuries, sports injuries, falls.

3. Spontaneous – occurring with minimal or no clear precipitant.
Common reported events or mechanical factors associated with the onset of symptoms include lifting small or large items, straining, stretching, positional changes, sporting activities, roller coaster rides and falls. Some of these might be categorized as traumatic.
a. Spontaneous spinal CSF leaks may be associated with spinal pathology such as calcified disc material or bone spurs. These leaks are usually ventral or in front of the spinal cord.
b. There is a growing evidence base suggesting that a significant proportion of spontaneous spinal CSF leaks occur as a result of preexisting dural weakness. A range of dural defects have been reported at surgery. Electron microscopy of dura has revealed abnormalities in a substantial proportion of cases. Heritable Disorders of Connective Tissue (HDCT) occur at a higher frequency in affected individuals; intracranial hypotension may be the first noted manifestation. Marfan syndrome, Ehlers-Danlos syndrome (both classic and hypermobility type) and Unspecified Heritable Disorders of Connective Tissue have been reported. Patients with spontaneous spinal CSF leaks have been shown to have higher risk of intracranial aneurysms, bicuspid aortic valve and thoracic aortic aneurysms and should be evaluated for HDCT.

Spontaneous spinal CSF leaks are uncommon, but not rare. One estimate of annual incidence is 5 in 100,000, however this has not been well-studied. Unfortunately, misdiagnoses and delayed diagnoses are common in this subset.

Key Points
– The use of pencil-point LP needles reduces the risk of post-dural puncture headache.
– Spontaneous spinal CSF leaks are recognized less readily than iatrogenic spinal CSF leaks.
– Spontaneous spinal CSF leaks are often associated with an underlying Heritable Disorder of Connective Tissue; intracranial hypotension may be the first noted manifestation.
– Spontaneous spinal CSF leaks are also associated with pre-existing spinal pathology.