0:00

So categorizing them, like I said earlier,

0:03

alluded to earlier into high and low flow is what the, the main role of MRI is.

0:07

The other secondary role of MRIs is to get a general region because digital

0:11

subtraction myography, uh,

0:13

and rapid CT myography for these high flow leaks is kind of the mainstay of

0:17

evaluation.

0:18

You really only get a very short temporal period to detect these leaks.

0:22

So you have to be in the right area, um,

0:24

because you're gonna be injecting only a finite amount of contrast,

0:26

you only inject three grams of contrast in the fecal sac.

0:29

And when you do a digital subtraction image,

0:31

you really only get two shots at seeing the leak.

0:33

So you really need to know about where it is. 'cause your detector for your, um,

0:36

your digital subtractions only gonna be about 20 centimeters,

0:39

so you're not gonna cover the whole spine in,

0:41

in a digital subtraction myelogram. Um, so if you can,

0:43

if you can see a pseudomeningocele that's tracking along the fecal sac,

0:47

you can get a general region where the leak is probably at,

0:49

and then you can focus on that region when you're doing either A D S M or

0:52

rapidly acquired CT gram, which I'll,

0:54

I'll go through that a little bit later as well.

0:55

They most frequently occur at either the cervical,

0:58

thoracic or thorac lumbar junction. The ventral epidural space, and again,

1:01

it's usually caused by disc herniation or visco osteophyte complex, um,

1:04

they focally leak directly into the epidural space in the acute setting,

1:08

but they're rarely caught in the acute setting because clinicians usually don't

1:11

pick up, uh,

1:12

on C S F leaks in the acute setting unless there's some inciting event like

1:16

trauma. Um, so oftentimes when they present,

1:18

they already have a chronic PST meningocele, low flow leaks. Um,

1:22

both acutely and chronically do tend to persistently leak into the epidural

1:26

space and rarely form chronic PST meninga seals.

1:29

Type twos occasionally will do that,

1:30

and it does make them harder to detect the exact location,

1:33

but it's easier to detect that there is a C S F leak because a pseudomeningocele

1:37

is easier to see than basically a focal pinpoint leak into the epidural space

1:41

without a pseudomeningocele. Um,

1:43

they typically occur in the lower thoracic region,

1:45

either laterally or posteriorly. Uh,

1:47

and they're often associated with a perinatal cyst or diverticulum, um,

1:52

and or osteophytes associated with the facet joints. So those are the,

1:55

the different types of leaks, and again,

1:57

categorizing into high and low flow based on the presence of a pseudo and anse

2:00

or a perineural cyst is critical for the next steps for those patients.