Tips on obliquity used to optimize ventral flow with L-TFESI?

[cameroncarter]

Hi all! What oblique angle do you use for your trajectory view for L-TFESIs? How do you determine this angle?

Sometimes I use 30-35deg (fellowship standard) but find my contrast stays dorsal.

Theoretically 20-25deg should position the needle to end at the anterior foramen but sometimes I hit the VB and find myself a touch lateral to mid-pedicle on AP.

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[RoloTomassi]

My RT's muscle memory. I don't know if she even knows. Just "looks right". But it's not uniform--less oblique for upper levels, more for lower levels and osteophytic foramens. You bend your needle? Should be pretty easy to retract a bit and correct.

 

[gaspasser127]

Hi all! What oblique angle do you use for your trajectory view for L-TFESIs? How do you determine this angle?

Sometimes I use 30-35deg (fellowship standard) but find my contrast stays dorsal.

Theoretically 20-25deg should position the needle to end at the anterior foramen but sometimes I hit the VB and find myself a touch lateral to mid-pedicle on AP.

I use way less than 30-35

Closer to 15

 

[lobelsteve]

I rarely oblique. I start true AP and guess depth before going lateral to confirm/adjust. Also, remember the shape of the pedicle and its shadow on Xray are not the same thing. Especially at L5.

 

[cameroncarter]

My RT's muscle memory. I don't know if she even knows. Just "looks right". But it's not uniform--less oblique for upper levels, more for lower levels and osteophytic foramens. You bend your needle? Should be pretty easy to retract a bit and correct.

I do bend! But I’ve been trying to master the 25G needle, which I find a lot harder to steer at depth. That’s why I’m trying to optimize initial oblique angle.

 

[Ducttape]

typically about 20 degrees. i look more at where the pedicle is with respect to the vertbral body before injecting.

typically i try to touch down on the inferior border of the pedicle before rotating to advance, as that gives me a depth before going to lateral.

 

[RoloTomassi]

I do bend! But I’ve been trying to master the 25G needle, which I find a lot harder to steer at depth. That’s why I’m trying to optimize initial oblique angle.

I like 23 ga. Perfect medium.

 

[SSdoc33]

we cant give you a number. every back is different. high riding iliac crests, wide hips on some women, etc

 

[cameroncarter]

I rarely oblique. I start true AP and guess depth before going lateral to confirm/adjust. Also, remember the shape of the pedicle and its shadow on Xray are not the same thing. Especially at L5.

Wow…this is amazing. Not there yet sadly.

 

[SSdoc33]

Wow…this is amazing. Not there yet sadly.

try not to get "there"

he is going too deep or too superficial if not starting the needle entry in oblique. start in oblique, get a good trajectory, then advance in AP.

 

[jwalker12]

why are you guys advancing in AP, whats the advantage? sorry not grasping why this would be beneficial opposed to staying in oblique

 

[runfastnow]

You can advance in oblique. Oblique gives little to no info on true depth. If you're really not paying attention can advance into dural space. I'll typically advance to what I think is ~80% of my final depth in oblique. Then finish in AP to make sure I don't go past the "6 o'clock" position (or just a mm past) on pedicle.

 

[RoloTomassi]

Article on likelihood of ventral spread and pain relief based on anterior-ness of needle tip:

Epidural Contrast Flow Patterns of Transforaminal Epidural Steroid Injections Stratified by Commonly Used Final Needle-Tip Position

Abstract. Objective. To evaluate the relationship between commonly used final needle-tip positions and subsequent contrast flow and patient-reported pain r

academic.oup.com

 

[oreosandsake]

I rarely oblique. I start true AP and guess depth before going lateral to confirm/adjust. Also, remember the shape of the pedicle and its shadow on Xray are not the same thing. Especially at L5.

But why.. why guess? Oblique makes your trajectory so simple

 

[SSdoc33]

why are you guys advancing in AP, whats the advantage? sorry not grasping why this would be beneficial opposed to staying in oblique

so you dont stick the nerve

 

[oneforfighting]

Oblique 10-20 deg. Advance until tissue texture change then go to lateral to advance to foramen. Inject a little dye. Go back to AP and inject more dye sometimes with live imaging.

 

[lobelsteve]

But why.. why guess? Oblique makes your trajectory so simple

I say guess. But truth is I know. MRI pulled up outside the room before i go in. Same as kypho. Know before you go.

 

[Analgesia108]

After squaring off the superior endplate, oblique ipsilaterally until the lateral border of the pedicle is within the lateral border of the vertebral body and go coaxial with a 25G needle aiming to just inferior to 6 'o clock - switch to AP & after injecting contrast under live, you will enjoy the beauty of medial spread 🙂

If hitting osteophytes or unable to enter the foramen & obtain epidural spread, retract a little, go lateral to assess and redirect as needed

 

[MitchLevi]

I only use lateral in a TFESI if I'm doing thoracic.

 

[DrMDAware]

I used to never use lateral. Now I do all the time. Gives me the answer for how deep I am in.

Line up sep. Start oblique. Touch pedicle. Slip under. Advance a bit. Go to lateral. See if I’m ventral enough. Very small amount of dye. If for some reason I need to see the traditional contrast spread I’ll take one AP view with a touch more contrast (not under live).

 

[docpain]

I oblique until the the SAP lateral border is sightly medial the 6 O'clock position of the pedicle above (this is typically around 30 degrees), then I drive the needle until I hit the lateral border of the SAP, then I slip lateral off of the SAP, then I go lateral with C arm, advance my needle until I am 2 mm in the foramen, needle position should divide the foramen into upper 2/3 and lower 1/3. Precise technique and works well.

 

[Forwho]

I oblique until the the SAP lateral border is sightly medial the 6 O'clock position of the pedicle above (this is typically around 30 degrees), then I drive the needle until I hit the lateral border of the SAP, then I slip lateral off of the SAP, then I go lateral with C arm, advance my needle until I am 2 mm in the foramen, needle position should divide the foramen into upper 2/3 and lower 1/3. Precise technique and works well.

i do about the same, oblique can be anywhere from 20-30 degrees. infraneural technique, safer. definitely need lateral though to avoid puncturing the disc. i do feel that contrast spread isn't as good compared to supraneural approach though

 

[powermd]

If they have reasonable disc height and no obvious obstructions in the foramen, I'll do the retro-discal technique at 30° first. If for some reason I'm not getting good dye flow, I'll switch to tunnel view under the pedicle. Last but not least, I'll just go straight squared AP and corkscrew in. My biggest headaches are the unseen osteophytes protruding from the transverse process, or the overgrown SAP that refuses to get out of the way.

 

[SpineandWine]

My technique is as follows for lumbar levels except L5-S1 for supranuclear approach
- get true AP, tilt 15 to 20 degrees
- coaxial needle to hit OS at junction of SAP (of level below) and TP-you’ll be hitting the “pedicle” hitting bone does feel like a deep pressure for patient but better than hitting nerve and causing transient pain aresthesias
- slide off OS and you should be in epidural space
- get AP to test epidural spread- can adjust according to spread- I look for contrast to medialize past pedicle. If you see this, don’t need lateral

For L5-S1, iliac crest may be in the way when you oblique, it that occurs, just do cranial tilt until that’s out of the way

Having the bone as a backdrop has been nice to gauge depth for me. I will say that you need to warn patients of a deep pressure

 

[deleted131481]

- get AP to test epidural spread- can adjust according to spread- I look for contrast to medialize past pedicle. If you see this, don’t need lateral

I used to never use lateral. Now I do all the time. Gives me the answer for how deep I am in.

I only use lateral in a TFESI if I'm doing thoracic.

Oblique 10-20 deg. Advance until tissue texture change then go to lateral to advance to foramen. Inject a little dye. Go back to AP and inject more dye sometimes with live imaging.

Lots of opinions on lateral view. I currently always do lateral out of habit but considering dropping it if AP looks good. I tend to agree with the first quote here. Any reason to do lateral if you are AP not past 6 o'clock position? Will you advance to 6 o'clock and stop if you still don't have medial spread, or go to lateral at that point and consider advancing more?

 

[lobelsteve]

SIS: 5 views.
AP
Lat
AP contrast
Lat contrast
Washout.

 

[DrMDAware]

Lots of opinions on lateral view. I currently always do lateral out of habit but considering dropping it if AP looks good. I tend to agree with the first quote here. Any reason to do lateral if you are AP not past 6 o'clock position? Will you advance to 6 o'clock and stop if you still don't have medial spread, or go to lateral at that point and consider advancing more?

I do lateral to make sure I’m more anterior than posterior in the space. The AP just lets me know I’m in the space.

 

[bedrock]

SIS: 5 views.
AP
Lat
AP contrast
Lat contrast
Washout.

I disagree. I spent part of my fellowship working a private practice with two SIS presidents and they certainly didn't do all of that. It isn't realistic outside of academics and frankly I don't agree with this much radiation for the patient or myself.

Asking everyone to do an AP and lateral is reasonable and I agree that sometimes things are missed if only AP.

Lets shoot for realistic goals.

 

[Baron Samedi]

I rarely oblique. I start true AP and guess depth before going lateral to confirm/adjust. Also, remember the shape of the pedicle and its shadow on Xray are not the same thing. Especially at L5.

Would you mind posting some pics when you get a chance?

I've read about a similar technique for a retroneural approach and have yet to try it. I typically do Scotty Dog supraneural/subpedicular or occasionally infraneural, but am interested in other approaches.

 

[lobelsteve]

I disagree. I spent part of my fellowship working a private practice with two SIS presidents in and they certainly didn't do all of that. It isn't realistic outside of academics and frankly I don't agree with this much radiation for the patient or myself.

Asking everyone to do an AP and lateral is reasonable and I agree that sometimes things are missed if only AP.

Lets shoot for realistic goals.

Tell Tim Maus.

 

[Taus]

Lots of opinions on lateral view. I currently always do lateral out of habit but considering dropping it if AP looks good. I tend to agree with the first quote here. Any reason to do lateral if you are AP not past 6 o'clock position? Will you advance to 6 o'clock and stop if you still don't have medial spread, or go to lateral at that point and consider advancing more?

If young patient/healthy spine except for a central/lat recess hnp…. Ill skip lateral if needle placement is routine and contrast spread is great on initial live run on ap. If not, I will go lateral.

I presume multiple runs of live contrast is more radiation than one or two still shots in lateral, then one run of live contrast in AP.

Old, arthritic spines, scoli, asymmetric collapse, foraminal stenosis, post fusion…. worth a quick lateral shot or two to optimize imho (to get their 2 weeks of relief w dex.…)

 

[epidural man]

Hi all! What oblique angle do you use for your trajectory view for L-TFESIs? How do you determine this angle?

Sometimes I use 30-35deg (fellowship standard) but find my contrast stays dorsal.

Theoretically 20-25deg should position the needle to end at the anterior foramen but sometimes I hit the VB and find myself a touch lateral to mid-pedicle on AP.

About 15 deg.

The worst (likely) outcome for TFESI - apart from an intraneural injection, is a wet tap.

So minimize this risk - less angle.

Also, with 15-20 deg, you will almost always be able to run the needle to the vertebral body and assure you are past the lateral pedicle border and not past the medial pedicle border.

If you want anterior spread, you need an anteriorly placed needle (most of the time).

If you want an anteriorly placed needle, you need a lateral view.

If you don’t care about getting medicine in the right spot and only care about reimbursement, skip the lateral.

If you are past the lateral pedicle border, you mostly will get epidural spread.

If you are talking T12-L2, I don’t rotate hardly at all. I get epidural spread very easily.

Let’s mark this date. I just want to know how long it takes you to abandon using a 25 gauge and go back to 22g. Maybe you’ll stick it out longer than I predict. But eventually you’ll make it back.

I drive in oblique en-face view. Feel for consistency change (or tell the resident/fellow to drive until they are nervous), then check AP, make a mental note of how much pedicle runway I have, then go lateral with a goal of the tip being in the anterior 3rd of foramen. Then to AP for contrast check.

Many of my colleagues do contrast in the lateral. What they are checking for - I can’t even begin to fathom…but they must see something important. (Maybe they think they are confirming anterior spread?)

 

[deleted875186]

About 15 deg.

The worst (likely) outcome for TFESI - apart from an intraneural injection, is a wet tap.

So minimize this risk - less angle.

Also, with 15-20 deg, you will almost always be able to run the needle to the vertebral body and assure you are past the lateral pedicle border and not past the medial pedicle border.

If you want anterior spread, you need an anteriorly placed needle (most of the time).

If you want an anteriorly placed needle, you need a lateral view.

If you don’t care about getting medicine in the right spot and only care about reimbursement, skip the lateral.

If you are past the lateral pedicle border, you mostly will get epidural spread.

If you are talking T12-L2, I don’t rotate hardly at all. I get epidural spread very easily.

Let’s mark this date. I just want to know how long it takes you to abandon using a 25 gauge and go back to 22g. Maybe you’ll stick it out longer than I predict. But eventually you’ll make it back.

I drive in oblique en-face view. Feel for consistency change (or tell the resident/fellow to drive until they are nervous), then check AP, make a mental note of how much pedicle runway I have, then go lateral with a goal of the tip being in the anterior 3rd of foramen. Then to AP for contrast check.

Many of my colleagues do contrast in the lateral. What they are checking for - I can’t even begin to fathom…but they must see something important. (Maybe they think they are confirming anterior spread?)

I never understood lateral contrast. You can see it spread a little superior in the epidural space, but how that is helpful I don’t know.

 

[lobelsteve]

I never understood lateral contrast. You can see it spread a little superior in the epidural space, but how that is helpful I don’t know.

I have seen it IT. Have seen it anterior to foramen. And posterior to spine.

 

[SC Tian]

My technique is as follows for lumbar levels except L5-S1 for supranuclear approach
- get true AP, tilt 15 to 20 degrees
- coaxial needle to hit OS at junction of SAP (of level below) and TP-you’ll be hitting the “pedicle” hitting bone does feel like a deep pressure for patient but better than hitting nerve and causing transient pain aresthesias
- slide off OS and you should be in epidural space
- get AP to test epidural spread- can adjust according to spread- I look for contrast to medialize past pedicle. If you see this, don’t need lateral

For L5-S1, iliac crest may be in the way when you oblique, it that occurs, just do cranial tilt until that’s out of the way

Having the bone as a backdrop has been nice to gauge depth for me. I will say that you need to warn patients of a deep pressure

Nice! Mine is only slightly different, I utilize ipsilateral oblique view to visualize the foramen, needle is advanced to touch sap ant tp junction, this is step 1, change to AP, walk the needle into foramen without leaving the bone to 6 o'clock, just like rfa needle, step 2, inject contrast step 3, check lateral for confirmation, step 4, skipped in most cases in recently years, as there were no modifications of placement.

 

[epidural man]

I have seen it IT. Have seen it anterior to foramen. And posterior to spine.

In a lateral, how could you tell it was IT?

Also, in the cases that you saw it posterior to the spine, or anterior to the foramen, what did the AP look like? Do it flow under the pedicle, and give the fat-bubble look that a typical epidurogram gives? I suspect that if you are getting extra-dural flow, it would be obvious in the AP. I also wonder if an IT injections would be obvious in the AP. The question is, what ADDITIONAL info does the lateral contrast picture give that isn’t contained in the AP?

I could be convinced to do contrast in lateral, just need more convincing info and data.

 

[lobelsteve]

I’m a lateral, how could you tell it was IT?

Also, in the cases that you saw it posterior to the spine, or anterior to the foramen, what did the AP look like? Do it flow under the pedicle, and give the fat-bubble look that a typical epidurogram gives? I suspect that if you are getting extra-dural flow, it would be obvious in the AP. I also wonder if an IT injections would be obvious in the AP. The question is, what ADDITIONAL info does the lateral contrast picture give that isn’t contained in the AP?

I could be convinced to do contrast in lateral, just need more convincing info and data.

Im not making this up. This is what SIS is saying to do. AP will look short of 6 under the pedicle in most cases. I have seen 6 in ap and been anterior to the foramen.

 

[knoxdoc]

Anyone wanna post some pics of their AP approach for an L5/1 TFESI? I always oblique about 20-25 degrees, but Mr. Pelvic Crest can get in my way and annoy the crap outta me. I'd love to have a straight AP technique as an alternative. Or, feel free to just post some APs with a dot indicating your needle target. Gracias.

 

[Taus]

Anyone wanna post some pics of their AP approach for an L5/1 TFESI? I always oblique about 20-25 degrees, but Mr. Pelvic Crest can get in my way and annoy the crap outta me. I'd love to have a straight AP technique as an alternative. Or, feel free to just post some APs with a dot indicating your needle target. Gracias.

Tilt image intensifier to head til iliac crest out of your way.

 

[knoxdoc]

Tilt image intensifier to head til iliac crest out of your way.

Yup, I do that. Just wondering where the target is on AP to avoid the hassle.

 

[SpineandWine]

Bringing up this old thread. Not sure how often people are getting paresthesias, but utilizing technique listed above with hitting Os on pedile and moving southward, I still occasionally get paresthesias (one of my pals claims he gets it less than 5% of times). I have not been able to replicate this as I get it ~20% for transient paresthesias.

Any tips in avoiding paresthesias? That part is the one that freaks patients out the most.

 

[callmeanesthesia]

I’ve noticed overall decrease in paresthesia and increase in rate of perfect epidurogram as I practice, but hard to say specifically what to change. Best advice I have is just to go very slowly when entering the neural foramen and warn patients they may feel a zing down the leg. Do you review and pre-plan your trajectory on MRI prior to procedure, to see whether you need to cranial or caudal tilt, and how much oblique is needed? Particularly above L4-5, the lordosis of the spine may cause your needle to be directed more downward into the foramen if you don’t caudal tilt.

 

[SpineandWine]

I’ve noticed overall decrease in paresthesia and increase in rate of perfect epidurogram as I practice, but hard to say specifically what to change. Best advice I have is just to go very slowly when entering the neural foramen and warn patients they may feel a zing down the leg. Do you review and pre-plan your trajectory on MRI prior to procedure, to see whether you need to cranial or caudal tilt, and how much oblique is needed? Particularly above L4-5, the lordosis of the spine may cause your needle to be directed more downward into the foramen if you don’t caudal tilt.

Don't necessarily utilize MRI for which TFESI, I do square off on fluoro in true AP prior to making any changes.

 

[RoloTomassi]

Bringing up this old thread. Not sure how often people are getting paresthesias, but utilizing technique listed above with hitting Os on pedile and moving southward, I still occasionally get paresthesias (one of my pals claims he gets it less than 5% of times). I have not been able to replicate this as I get it ~20% for transient paresthesias.

Any tips in avoiding paresthesias? That part is the one that freaks patients out the most.

Staying high, right under pedicle, and advancing slowly. The technique above I'm not a fan of, because advancing downward you are going more towards the nerve the further you go, rather than staying horizontal right under the pedicle.

 

[Blackmateria]

About 15 deg.

The worst (likely) outcome for TFESI - apart from an intraneural injection, is a wet tap.

So minimize this risk - less angle.

Also, with 15-20 deg, you will almost always be able to run the needle to the vertebral body and assure you are past the lateral pedicle border and not past the medial pedicle border.

If you want anterior spread, you need an anteriorly placed needle (most of the time).

If you want an anteriorly placed needle, you need a lateral view.

If you don’t care about getting medicine in the right spot and only care about reimbursement, skip the lateral.

If you are past the lateral pedicle border, you mostly will get epidural spread.

If you are talking T12-L2, I don’t rotate hardly at all. I get epidural spread very easily.

Let’s mark this date. I just want to know how long it takes you to abandon using a 25 gauge and go back to 22g. Maybe you’ll stick it out longer than I predict. But eventually you’ll make it back.

I drive in oblique en-face view. Feel for consistency change (or tell the resident/fellow to drive until they are nervous), then check AP, make a mental note of how much pedicle runway I have, then go lateral with a goal of the tip being in the anterior 3rd of foramen. Then to AP for contrast check.

Many of my colleagues do contrast in the lateral. What they are checking for - I can’t even begin to fathom…but they must see something important. (Maybe they think they are confirming anterior spread?)

How deep are people going into the foramen in lateral? I was always taught to aim to be in the superio-posterior portion by a millimeter or two because vasculature is more likely to be anterior, but I have seen some procedure notes document being in 12 o'clock position of the foramen, and it seems like some even try to be in the anterior foramen.

 

[SpineandWine]

Staying high, right under pedicle, and advancing slowly. The technique above I'm not a fan of, because advancing downward you are going more towards the nerve the further you go, rather than staying horizontal right under the pedicle.

Would you square end plates and stay underneath pedicle shadow pointing to pedicle?
Is that what you mean?

 

[Taus]

Staying high, right under pedicle, and advancing slowly. The technique above I'm not a fan of, because advancing downward you are going more towards the nerve the further you go, rather than staying horizontal right under the pedicle.

Agreed. I much prefer to come from a bit of a caudal to cephalad approach, more parallel to the exiting nerve root, as opposed to perpendicular. A nice tip I picked up from a Tim Maus lecture: tilt the II until pars overlaps with tp, seeing one crisp straight line. You’ll find yourself coming in same plane as inferior pedicle when you look under lateral. I focus on that for proper tilt, not endplates.

 

[epidural man]

How deep are people going into the foramen in lateral? I was always taught to aim to be in the superio-posterior portion by a millimeter or two because vasculature is more likely to be anterior, but I have seen some procedure notes document being in 12 o'clock position of the foramen, and it seems like some even try to be in the anterior foramen.

I suggest when you are looking at sagital cuts, start paying attention to where the blood vessels are in the foramen.

What you will see is that they are all over the place. Any attempt to try and miss them in any certain quadrant is a fool’s errand.

 

[RoloTomassi]

How deep are people going into the foramen in lateral? I was always taught to aim to be in the superio-posterior portion by a millimeter or two because vasculature is more likely to be anterior, but I have seen some procedure notes document being in 12 o'clock position of the foramen, and it seems like some even try to be in the anterior foramen.

Ideally superior-anterior. Higher chance of ventral epidural spread

 

[SpineandWine]

Agreed. I much prefer to come from a bit of a caudal to cephalad approach, more parallel to the exiting nerve root, as opposed to perpendicular. A nice tip I picked up from a Tim Maus lecture: tilt the II until pars overlaps with tp, seeing one crisp straight line. You’ll find yourself coming in same plane as inferior pedicle when you look under lateral. I focus on that for proper tilt, not endplates.

Having a hard time imaging PARS overlapping with TP. Do you have a picture demonstrating it?