0:00

So with that, I'm gonna move on to, um, localization of these leaks. Um, again,

0:05

detectability and accuracy, uh,

0:06

of localization is highly dependent upon the rate of,

0:09

of the leak as well as the consistency. Um,

0:12

and the associated extent of the pseudomeningocele, the sto menil is very focal.

0:16

Then it's, it's not really a big problem, you know, about where the leak is,

0:19

but if it's a really long one that extends along most of the spine,

0:22

then you really have to be a lot more, uh, judicious in your imaging and,

0:25

and image very quickly. If it's a high flow leak. Again,

0:27

high flow acute leaks are easy to detect,

0:29

but clinicians usually don't pick up on them until they're later on in their

0:32

course. The patients don't even suspect it usually. Um, and then, uh,

0:36

chronic leaks, um, that are high flow or easier to detect presence, meaning we,

0:41

we know where they are,

0:42

but accurately localizing them can be extremely difficult just because the

0:45

pseudo meninga seals, again, can be very extensive. Um,

0:48

both acute and chronic slow C S f leaks as well as intermittent leaks are

0:51

difficult to detect and localized because these patients often have more than

0:55

one abnormality of their fecal sac. They'll have multiple perineural cysts,

0:58

so you have to look at multiple different regions and,

1:01

and narrowing it down a little bit can help a lot. Um, so again, um,

1:06

the high flow leaks are typically the type type ones and the type twos. Um,

1:10

low flow leaks, type twos, threes,

1:12

or fours can be kind of slower or low flow leaks. Um,

1:15

I normally do a screening m r i on on both of them, again,

1:18

to evaluate for psdo meningocele and those type two and type one leaks.

1:21

And then looking for peral cysts, uh, in the type twos through fours. Um,

1:25

and then if I'm dealing with a high flow leak or suspected high flow leak based

1:29

on the detection of a pseudo meningocele,

1:30

then I'm gonna do either a very fast pressure neutral ct.

1:34

What that means is I'm gonna put the patient on a bolster in ct,

1:38

do the spinal tap there, and actually put the contrast in,

1:41

pull the bolster out and scan immediately with a large field of view.

1:44

So I can see the contrast as it flows up and I can see the, uh, the,

1:47

the exact moment or the exact location of the leak without filling the entire

1:51

pseudo and inae and obscuring my, my focal area of dehiscence. Um,

1:55

you can also do digital subtraction myography.

1:57

The benefit to digital subtraction is that you can actively watch the contrast

2:01

flow up and, and see where it's leaking from the downside to it.

2:04

Particularly in heavier patients, it can be really difficult to,

2:06

to accurately localize the leak because there there's only, um, uh,

2:11

only so much penetration you can get, um, through the shoulders,

2:14

particularly at the cervical thoracic junction.

2:17

And a lot of these leaks are at the cervical thoracic junction.

2:19

So you can have problems with the shoulders, even on oblique, um,

2:22

seeing exactly where it is, particularly on a heavier patient.

2:24

So on heavier patients, I tend to lean towards, uh,

2:27

a fast pressure neutral CT milligram. Um, whereas on, on thinner patients,

2:31

I tend to go more for digital subtraction myelography and watch the contrast

2:35

come up for slow flow leaks. Um, again,

2:38

I do the screening m R I and I'm looking for, again, perineural cyst. Um,

2:42

and I will normally put them in the lateral de cubit disposition of the side

2:45

that's most suspicious to me and either do, uh, a pressure augmented, um,

2:49

CT gram with plus or minus some delayed imaging and doing everything in ct.

2:53

Or I'll do a digital subtraction and do the same thing.

2:56

Basically I'll watch it with pressure augmentation over time,

2:59

Um, and, and look for, um, uh, those slower leaks. Um,

3:03

you can also do contrast enhanced m r i my myography with or without pressure

3:07

augmentation. You can basically inject gadolinium into the fecal sac,

3:10

which is also a useful tool. And I, I'll go over that in a minute and how,

3:12

how I do it. Um, you can also do nuclear medicine stenography, but I,

3:17

I find that to be of limited value unless you're dealing with fairly large

3:20

perineural cysts. If they're very large and there, there are multiples. Um,

3:24

nuclear medicine actually can be very useful, um, for those cases.

3:27

But for smaller cysts it can be really,

3:29

really difficult 'cause they kind of blend into the fecal sac on nuclear

3:32

medicine cystography. But in patients with massive dur ectasia, like,

3:36

like those with Marfan syndrome, things like that,

3:38

nuclear medicine can be helpful and it can detect it.