Epidural Technique

[mille125]

Yes, it really does leave a doubt you are in the epidural space.
Thats why we have fluoroscopy and contrast.


And what percent of patients have no ligamentum flavum to give you that first LOR?

Hanging drop through the dura happens.

Dural puncture can happen with any technique (we have all proved that at some point in our training). During fellowship I did have two dural punctures using this technique. Both had a transient parasthesia with obvious CSF in the tuohy. Thankfully neither patient had a headache. I am convinced that it was due to my inexperience at the time. Those of us that use the hanging drop technique would probably agree that the findings can be subtle sometimes.

I feel that it is a superior technique in experienced hands because there are so many "false losses of resistance" in the cervical spine. I have found that visualizing the disappearance of the drop has had 100% corrolation with being in the epidural space (n>1000). I still inject contrast in all of my patients if for nothing else to see filling patterns. There is one patient that I did omit contrast (anaphylactic reaction of contrast dye). He had a very very good result.

Steve, I dont know which technique you use. My understanding with the hanging drop technique is that it involves tenting the dura. I do not see how having or not having a ligamentum flavum would affect the technique at all. Maybe you can explain that to me.

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[Tenesma]

the LOR is very dependent on gauge of needle and expertise of practitioner... when you use a 14 gauge for a SCS the LOR is very different from a 17g for an epidural cath which is very different with a 20 or 22g needle... and also frequency of procedures within a finite period of time

hanging drop works for some --- but not for all - there are some devices designed to measure pressure changes - but we all have been fooled by false loss of resistance ---

 

[mehul_25]

The Candido study which was first presented at ASRA fall 20066 inspired us to present a study looking at needle placement in either the lateral or medial aspect of the interlaminar space. Although lateral placement was more likely to reach the anterior space it only occured ~35% of the time albeit with limited contrast volumes. Similar findings were published by Wiel et al. in March 2008.

 

[MN1]

It is unclear in this study whether for TFESIs, they placed the needle in the dorsal or ventral neuroforamen.

The last ISIS course I was at, most (not all) of the faculty recommended staying in the DORSAL aspect of the neuroforamen.

 

[Ligament]

The last ISIS course I was at, most (not all) of the faculty recommended staying in the DORSAL aspect of the neuroforamen.

What was the rationale?

 

[MN1]

What was the rationale?

The rationale was to avoid the artery.


In fact, one of the faculty members said the following (and said it very strongly):
"I've done thousands of TF epidurals and never had any problems. If you want to make sure you avoid a spinal cord infarct, do the following four things: 1) always stay dorsal in the neuroforamen, 2) perform a test dose with lidocaine, 3) use a non-particulate steroid, 4) use a 25 gauge needle"

 

[mehul_25]

The rationale was to avoid the artery.


In fact, one of the faculty members said the following (and said it very strongly):
"I've done thousands of TF epidurals and never had any problems. If you want to make sure you avoid a spinal cord infarct, do the following four things: 1) always stay dorsal in the neuroforamen, 2) perform a test dose with lidocaine, 3) use a non-particulate steroid, 4) use a 25 gauge needle"

why not just use saline alone...

 

[dc2md]

2) perform a test dose with lidocaine

Why? What would that do? Why not just use contrast?

 

[Ligament]

The rationale was to avoid the artery.


In fact, one of the faculty members said the following (and said it very strongly):
"I've done thousands of TF epidurals and never had any problems. If you want to make sure you avoid a spinal cord infarct, do the following four things: 1) always stay dorsal in the neuroforamen, 2) perform a test dose with lidocaine, 3) use a non-particulate steroid, 4) use a 25 gauge needle"

There is no evidence that staying dorsal in the neuroforamen is any safer than ventral. Staying dorsal in the neuroforamen would theoretically (since it has not been studied) deliver some or all medication to the dorsal epidural space, which defeats the purpose of the TFESI in the first place.

Secondly, lets say you do a test dose of lidocaine, and 15 minutes later the patient develops weakness in the leg. There was no weakness 2 minutes after the test dose. So what do you have now? How do you know there is no developing epidural hematoma vs. the effects of the local?

The use of non-particulate steroid as a safety mechanism is still a theoretical advantage.

I use a 27 gauge whitacre needle. Thats better than a 25 quincke. Its much safer and you will NEVER have a cord infarct with this needle. 25ga needles are cruel, dangerous, and are malpractice in this day and age. What the heck is ISIS teaching?!

 

[dc2md]

25ga needles are cruel, dangerous, and are malpractice in this day and age.

You use 27 gauge for TF ESI? We're using 22g. What's cruel about that? The only painful part is the initial 1% lidocaine skin anesthesia...except when i accidentally poke the spinal nerve. Oops! But that's been very temporary (<5-10 minutes) so far.

By the way, Ligament, how do you reach the anterior/ventral epidural space doing TFs...what's your approach?

 

[ampaphb]

There is no evidence that staying dorsal in the neuroforamen is any safer than ventral. Staying dorsal in the neuroforamen would theoretically (since it has not been studied) deliver some or all medication to the dorsal epidural space, which defeats the purpose of the TFESI in the first place.

Secondly, lets say you do a test dose of lidocaine, and 15 minutes later the patient develops weakness in the leg. There was no weakness 2 minutes after the test dose. So what do you have now? How do you know there is no developing epidural hematoma vs. the effects of the local?

The use of non-particulate steroid as a safety mechanism is still a theoretical advantage.

I use a 27 gauge whitacre needle. Thats better than a 25 quincke. Its much safer and you will NEVER have a cord infarct with this needle. 25ga needles are cruel, dangerous, and are malpractice in this day and age. What the heck is ISIS teaching?!

NEVER? Got any evidence to back THAT up?

 

[Ligament]

NEVER? Got any evidence to back THAT up?

I was being sarcastic in response to the ISIS instructor who was advocating a 25ga needle. If 25ga is "better" than 22ga then 27ga must be "better" than 25ga right?

Actually, I've been using 27ga whitacres lately and like them, but in no way, shape, or form would I suppose they are better or safer than 25ga or even 22ga needles. Probably safer than 14 gauge needles, however

 

[Ligament]

You use 27 gauge for TF ESI? We're using 22g. What's cruel about that? The only painful part is the initial 1% lidocaine skin anesthesia...except when i accidentally poke the spinal nerve. Oops! But that's been very temporary (<5-10 minutes) so far.

By the way, Ligament, how do you reach the anterior/ventral epidural space doing TFs...what's your approach?

I just use the ISIS subpedicular approach, not the ISIS retroneural approach.

 

[Tenesma]

the 27g are WAY Too flimsy in my adipose-laden patients

the 25g is my weapon of choice

needle position doesn't matter as long as you get good/acceptable contrast spread

i don't think the smaller the needle the lower the likelihood of cord infarction... especially since we presume cord infarction is due to particulate nature of certain steroids..

 

[Mister Mxyzptlk]

In fact, one of the faculty members said the following (and said it very strongly):
"I've done thousands of TF epidurals and never had any problems. If you want to make sure you avoid a spinal cord infarct, do the following four things: 1) always stay dorsal in the neuroforamen, 2) perform a test dose with lidocaine, 3) use a non-particulate steroid, 4) use a 25 gauge needle"

Great. Another unsubstantiated "standard of care". He forgot DSA and blunt needles.

 

[Ligament]

Great. Another unsubstantiated "standard of care". He forgot DSA and blunt needles.

Gorback, you and Algos are ISIS bigwigs...do the ISIS instructors have any direction in what and how to teach techniques at the courses? I would assume yes, but then we hear of statements like the above...

 

[MN1]

There is no evidence that staying dorsal in the neuroforamen is any safer than ventral. Staying dorsal in the neuroforamen would theoretically (since it has not been studied) deliver some or all medication to the dorsal epidural space, which defeats the purpose of the TFESI in the first place.

Secondly, lets say you do a test dose of lidocaine, and 15 minutes later the patient develops weakness in the leg. There was no weakness 2 minutes after the test dose. So what do you have now? How do you know there is no developing epidural hematoma vs. the effects of the local?

The use of non-particulate steroid as a safety mechanism is still a theoretical advantage.

I use a 27 gauge whitacre needle. Thats better than a 25 quincke. Its much safer and you will NEVER have a cord infarct with this needle. 25ga needles are cruel, dangerous, and are malpractice in this day and age. What the heck is ISIS teaching?!

Don't shoot the messenger.....just passing on what is being taught at ISIS courses.

 

[Ligament]

Don't shoot the messenger.....just passing on what is being taught at ISIS courses.

MN1, nothing directed toward you at all, no worries.

 

[Mister Mxyzptlk]

Gorback, you and Algos are ISIS bigwigs...do the ISIS instructors have any direction in what and how to teach techniques at the courses? I would assume yes, but then we hear of statements like the above...

Algos is a bigwig. I am just a gadfly. ISIS wants their instructors to go "by the book", i.e., the Guidelines at the cadaver courses. Unfortunately the instructors can't resist teaching "here's how I do it", which is frowned upon by the leadership.

During the lectures they can say whatever they want.

 

[dc2md]

I can't seem to find a source for the typical placement of the nerve root/DRG/mixed nerve in the IVF. I always learned before that the nerve pretty much hugs along the pedicle and therefore is in the superior aspect of the IVF and therefore immune to only far posterolateral disc bulges/herniation. What do you all know about that?

ALSO, it seems then that a subpedicular needle approach would be more likely to hit the nerve. No??

 

[Aether2000]

I am not an ISIS luminary, but one among many that do what we can to advance the field. The teachings during the courses tend to adhere to the ISIS Guidelines, with the understanding that they represent the expert consensus safest and most effective techniques when they were published. They do not represent the only technique and may require patient specific modification. As we gain more knowledge through scientific studies (such as the many presented during the annual meeting this year), we are able to fine tune the techniques even further. Individual ISIS instructors may have slight variations on the approach, or more often, discuss "pearls" that may make the standard or alternative approaches (when necessary) easier. For many issues, there will always be some personal preferences of physicians that are defined by their experience, patient population, office vs ASC vs hospital venue, skills, and tolerance for change. I personally find 25ga needles too flimsy for some of my nearly spherical patients, that at times require 7 or 8 inch needles to reach the target. Anyway, I diverge...
The ISIS instructors are overall of a very high quality with a significant grey/black hair ratio. ISIS accepts new instructors only after a one on one demonstration of competence and anatomical placement (hands on), so they are fairly fungible.

 

[PMR 4 MSK]

I can't seem to find a source for the typical placement of the nerve root/DRG/mixed nerve in the IVF. I always learned before that the nerve pretty much hugs along the pedicle and therefore is in the superior aspect of the IVF and therefore immune to only far posterolateral disc bulges/herniation. What do you all know about that?

ALSO, it seems then that a subpedicular needle approach would be more likely to hit the nerve. No??

Take some free time and go spend some time with a radiologist reading spinal MRI's - you'll be able to see exactly where they lie - usually a couple mm below the pedicle in the IVF, but with a clear fluid outline on T2.

Far lat HNP certainly can hit the DRG, can even extrude into IVF or sequester into it at times (neurosurgeons love those - easy plucking with micro approach). Nerve root can be hit by any aspect of a HNP except small central HNP in to L-Spine, as typically within the canal they congregate in the posterior aspect of the canal (at least while supine for the 45 min MRI). Typically paracentral HNP hits the nerve root below, far lateral hits the nerve root at the HNP level.

 

[dc2md]

Take some free time and go spend some time with a radiologist reading spinal MRI's - you'll be able to see exactly where they lie - usually a couple mm below the pedicle in the IVF, but with a clear fluid outline on T2.

Thanks PMR 4 MSK. I did a radiology month at the VA my second month of my internship but we didn't have an MRI (post-Katrina situation).

 

[ampaphb]

I am not an ISIS luminary, but one among many that do what we can to advance the field. The teachings during the courses tend to adhere to the ISIS Guidelines, with the understanding that they represent the expert consensus safest and most effective techniques when they were published. They do not represent the only technique and may require patient specific modification. As we gain more knowledge through scientific studies (such as the many presented during the annual meeting this year), we are able to fine tune the techniques even further. Individual ISIS instructors may have slight variations on the approach, or more often, discuss "pearls" that may make the standard or alternative approaches (when necessary) easier. For many issues, there will always be some personal preferences of physicians that are defined by their experience, patient population, office vs ASC vs hospital venue, skills, and tolerance for change. I personally find 25ga needles too flimsy for some of my nearly spherical patients, that at times require 7 or 8 inch needles to reach the target. Anyway, I diverge...
The ISIS instructors are overall of a very high quality with a significant grey/black hair ratio. ISIS accepts new instructors only after a one on one demonstration of competence and anatomical placement (hands on), so they are fairly fungible.

For those not lucky enough to have attended the Las Vegas ISIS meting, let's just say that Algos' minor tangential reference pales in comparison to the multiple topics, multiple hairpin turns, not so subtle and barely hidden agendas, vastly over the time alotted, but exceedingly entertaining talk another speaker/SDN poster presented.

We also use 3 1/2 or 4 11/16" 25's, but when we get to those requiring 6-8" needles, increase our guage to 22 as well.

 

[dc2md]

8" needles?? WOW!! must've been some damn good beignets, gumbo and jambalaya to cause that amount of cajun adipose.

 

[ampaphb]

.

 

[ampaphb]

8" needles?? WOW!! must've been some damn good beignets, gumbo and jambalaya to cause that amount of cajun adipose.

Not sure about your population you see, but mine are far more Creole than Cajun - Acadiana is 2-3 hours west of NOLA.

 

[lovebailey2001]

One rudimentory Q! what position do u guys use for TLESIs, prone or lat. decubitus...

 

[specepic]

Dural puncture can happen with any technique (we have all proved that at some point in our training). During fellowship I did have two dural punctures using this technique. Both had a transient parasthesia with obvious CSF in the tuohy. Thankfully neither patient had a headache. I am convinced that it was due to my inexperience at the time. Those of us that use the hanging drop technique would probably agree that the findings can be subtle sometimes.

I feel that it is a superior technique in experienced hands because there are so many "false losses of resistance" in the cervical spine. I have found that visualizing the disappearance of the drop has had 100% corrolation with being in the epidural space (n>1000). I still inject contrast in all of my patients if for nothing else to see filling patterns. There is one patient that I did omit contrast (anaphylactic reaction of contrast dye). He had a very very good result.

Steve, I dont know which technique you use. My understanding with the hanging drop technique is that it involves tenting the dura. I do not see how having or not having a ligamentum flavum would affect the technique at all. Maybe you can explain that to me.

Are you using a lateral image to go along with the hanging drop tech?