Interscalene block - general consensus on where to needle?

[propadex]

Where do you guys routinely put your needle tip when performing your interscalene blocks? I've read resources that say multiple conflicting things:

-"Needle aimed in between nerve roots instead of directly at them in order to minimize risk of accidental nerve injury" (Nysora). But then the same resource goes on to say
"It is prudent to avoid injecting between the nerves coming from a single root, as this may result in an intraneural injection"

So when you are looking at 3-5 black circles in the interscalene groove, how do you differentiate which ones are C5, C6, C7 vs. multiples coming off the same root? For example how do we know in the picture below that we are not looking at C5, C6, C6, C7 (or any other anatomical variant).

Or do you simply inject tangential to the posterior border of the cluster of 3 "stoplights"?

Or do you inject tangential to the superior border of the cluster? In my mind this is incorrect because superior deposition I think will likely lead to anterior spread and increased phrenic nerve blockade.

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[GaseousClay]

If there’s a nice gap between upper and middle trunk will place some on one side then go inbetween then go to other side and inject if upper and middle trunk are tight then will inject near the upper middle trunk then hydrodissect over the top and go to other side.

 

[GassYous]

I just go wherever the spread looks good and the patient isn't complaining

 

[Arch Guillotti]

I just go wherever the spread looks good and the patient isn't complaining

Exactly. Keep it simple.

 

[DocVapor]

I just go wherever the spread looks good and the patient isn't complaining

Quoting for out-of-context applications.

 

[abolt18]

I initially learned, trying to get local all around. Then we had a guy who did a regional fellowship come to our university and he taught me you can just deposit all your local posterior to the nerves, no need to chase your needle between the nerve roots. Apparently this gives you less risk of damaging nerves as well as slightly less phrenic involvement.

I perceived no difference in the block quality when I started just dumping it all posterior, and it's easy, so I'll keep doing it.

 

[Barleycorn]

I initially learned, trying to get local all around. Then we had a guy who did a regional fellowship come to our university and he taught me you can just deposit all your local posterior to the nerves, no need to chase your needle between the nerve roots. Apparently this gives you less risk of damaging nerves as well as slightly less phrenic involvement.

I perceived no difference in the block quality when I started just dumping it all posterior, and it's easy, so I'll keep doing it.

This is what I do as well, just a little pocket behind the stoplight. No need to go jabbing the needle all around the roots like we learned in residency.

 

[deleted697535]

Wait whats that straight line bright object in your images? Never seen that before on ultrasound

 

[GassYous]

Wait whats that straight line bright object in your images? Never seen that before on ultrasound

Reverberation artifact from the ultrasound beam

 

[DrOwnage]

When you say posterior what exactly do you mean? Since the block is an inplane block lateral to medial.

 

[Gnarvin]

When you say posterior what exactly do you mean? Since the block is an inplane block lateral to medial.

I would not say that the block is done in a purely lateral to medial plane. It is done in a more posterolateral to anteromedial fashion. The person meant to keep the needle on lateral/posterior part of the plexus. Or if you want to go by anatomy, the portion of the plexus that is bordered by the middle scalene muscle.

 

[anbuitachi]

 

[vector2]

When looking at it in anatomic position, the plexus ("stoplight") lies almost totally horizontal, but yet our U/S anatomy shows the stoplight vertically. This means our needle approach is both L->M and P->A, anatomically speaking, as the previous poster said.

 

[Groove]

Where do you guys routinely put your needle tip when performing your interscalene blocks? I've read resources that say multiple conflicting things:

-"Needle aimed in between nerve roots instead of directly at them in order to minimize risk of accidental nerve injury" (Nysora). But then the same resource goes on to say
"It is prudent to avoid injecting between the nerves coming from a single root, as this may result in an intraneural injection"
View attachment 341009
So when you are looking at 3-5 black circles in the interscalene groove, how do you differentiate which ones are C5, C6, C7 vs. multiples coming off the same root? For example how do we know in the picture below that we are not looking at C5, C6, C6, C7 (or any other anatomical variant).
View attachment 341016

Or do you simply inject tangential to the posterior border of the cluster of 3 "stoplights"?
View attachment 341014

Or do you inject tangential to the superior border of the cluster? In my mind this is incorrect because superior deposition I think will likely lead to anterior spread and increased phrenic nerve blockade.
View attachment 341010

EM here. I routinely do interscalene for shoulder reductions but I'm sure my frequency with the procedure is far less than anesthesia. I think you're overthinking it. I keep the volume under 10cc and infiltrate just inferior and posterior to the nerve roots. I have a thorough discussion with the pt before hand about alerting me if they feel any lancinating pain and if they report it during injection, I adjust accordingly. I used to really get bent out of shape about the phrenic nerve palsy and would routinely ultrasound the diaphragm after the block while making subtle adjustments for each procedure to see if any particular technique would decrease the incidence. What I found was that if you keep the deposition to the top nerve root at a minimum (and still under 10cc total for the procedure, ~3cc per root) and keep the deposition inferior and posterior, it seems to minimize the phrenic nerve palsy. To consistently avoid phrenic nerve palsy, I found myself suffering inefficient blocks to the point where I felt phrenic nerve paralysis was unavoidable. Which...one of you guys on here had told me that a long time ago when I started doing these and it's true. Someone from here said "You'll bag the phrenic 100% of the time if you want a good block" or something to that effect and they were right in my experience.

 

[sevoflurane]

25cc’s .25 percent. I make sure to dump some of that anterior/posterior and superior to *C5 for quick onset. The rest can go anywhere.
Supraclav if bad COPD.

 

[Arch Guillotti]

Supraclav if bad COPD.

It doesn’t make a difference. Fake news.

 

[sevoflurane]

It doesn’t make a difference. Fake news.

What’s the incidence of hemidiaphragmstic paralysis in ISB vs SCB?

 

[sevoflurane]

It doesn’t make a difference. Fake news.

I’ll just leave this here @Arch Guillotti

 

[Volatile]

I’ll just leave this here @Arch Guillotti

View attachment 341483

34-52 ml?? They’ll be numb for their follow up appt 😂

I always aim for the upper most nerve root on in interscalene, whether that’s c4, c5, c6 who really knows but in mind I’m trying to cover the shoulder which is mostly c5, so I see no point in directing my needle lower on the “stop light.” That’s also why I feel I absolutely should get phrenic nerve paralysis w/ a good interscalene block for a shoulder procedure. If you’re not getting the phrenic, you’re probably getting an inferior block for the procedure.
I stopped splitting c5 and c6 after training, haven’t found that it’s necessary, I dump the local posterior and it seems to work fine.

if I’m worried about their lungs, I do a suprascapular w/ an axillary. I’m probably at an N of 12 or so, doesn’t work quite as well but much better than I thought it would 🤷🏼‍♂️

 

[GassYous]

34-52 ml?? They’ll be numb for their follow up appt 😂

I always aim for the upper most nerve root on in interscalene, whether that’s c4, c5, c6 who really knows but in mind I’m trying to cover the shoulder which is mostly c5, so I see no point in directing my needle lower on the “stop light.” That’s also why I feel I absolutely should get phrenic nerve paralysis w/ a good interscalene block for a shoulder procedure. If you’re not getting the phrenic, you’re probably getting an inferior block for the procedure.
I stopped splitting c5 and c6 after training, haven’t found that it’s necessary, I dump the local posterior and it seems to work fine.

if I’m worried about their lungs, I do a suprascapular w/ an axillary. I’m probably at an N of 12 or so, doesn’t work quite as well but much better than I thought it would 🤷🏼‍♂️

Interscalene should be 10-20 lol

 

[sevoflurane]

34-52 ml?? They’ll be numb for their follow up appt 😂

I always aim for the upper most nerve root on in interscalene, whether that’s c4, c5, c6 who really knows but in mind I’m trying to cover the shoulder which is mostly c5, so I see no point in directing my needle lower on the “stop light.” That’s also why I feel I absolutely should get phrenic nerve paralysis w/ a good interscalene block for a shoulder procedure. If you’re not getting the phrenic, you’re probably getting an inferior block for the procedure.
I stopped splitting c5 and c6 after training, haven’t found that it’s necessary, I dump the local posterior and it seems to work fine.

if I’m worried about their lungs, I do a suprascapular w/ an axillary. I’m probably at an N of 12 or so, doesn’t work quite as well but much better than I thought it would 🤷🏼‍♂️

Who TF uses 40-50+ mls!?!? 😂😂

That is 1990 style ISB.

 

[sevoflurane]

and yeah… suprascapular 100% doesn’t work as well and is def. a harder block in the obese.

 

[sevoflurane]

I’ll go low dose supraclav over axillary/suprascapular 100% of the time

 

[sevoflurane]

ISB from this morning. Do it this way pretty much every time. Start by hydrodissecting keeping the needle away from the B.P. Then move up and over C5. This particular patient’s block set up in about 7 minutes, so no intraop norcotics necessary.

 

[GassYous]

ISB from this morning. Do it this way pretty much every time. Start by hydrodissecting keeping the needle away from the B.P. Then move up and over C5. This particular patient’s block set up in about 7 minutes, so no intraop norcotics necessary.

View attachment 341583

That's how I like to do it too. Doesn't always come out so pretty

 

[anbuitachi]

ISB from this morning. Do it this way pretty much every time. Start by hydrodissecting keeping the needle away from the B.P. Then move up and over C5. This particular patient’s block set up in about 7 minutes, so no intraop norcotics necessary.

View attachment 341583

we need a video

 

[Arch Guillotti]

I’ll just leave this here @Arch Guillotti

View attachment 341483

Non u/s guide interscalene block with 50+ cc’s of local? Nice.

 

[deleted126335]

Non u/s guide interscalene block with 50+ cc’s of local? Nice.

Like Sevo said.

1990 type block. Nerve stimulator. Different approach with needle. Worked great. Except for the odd disaster or near disaster. Which was about 1-2 orders of magnitude more common with that technique.

 

[sevoflurane]

Non u/s guide interscalene block with 50+ cc’s of local? Nice.

Lol…. that’s not the point.

 

[Skribbles]

I'll address your points individually:

Where do you guys routinely put your needle tip when performing your interscalene blocks?

I routinely inject under the "stoplight", that is under the C6 nerve root. I look for either posterior or anterior spread (ideally, you want both).

"It is prudent to avoid injecting between the nerves coming from a single root, as this may result in an intraneural injection

What they mean is typically the C6 nerve root appears to split, but it's actually still a single nerve. I have seen some people attempt to inject between the "two" C6 roots and I cringe so hard as that is definitely an intraneural injection. It's still a single nerve root, but it appears under ultrasound to be 2 distinct nerves, it's not. Don't split C6

Additionally, there is evidence that the C5 and C6 nerve roots share an epineurium, which is why some hesitate to even split C5 and C6 as shown in one of your images. You're likely not goin to do much damage doing so, but why do an intra-epineural injection if you don't have to?

So when you are looking at 3-5 black circles in the interscalene groove, how do you differentiate which ones are C5, C6, C7 vs. multiples coming off the same root? For example how do we know in the picture below that we are not looking at C5, C6, C6, C7 (or any other anatomical variant).

You continue to scan cephalad and watch the nerve roots dive into their foramen. The cervical spinal column have anterior and posterior tubercles that you can see the nerve roots diving inbetween. But the C7 vertebra has prominent posterior tubercle, it has basically no anterior tubercle which allows you to definitively track the C7 root back to the brachial plexus.
1-s2.0-S2211568414000217-gr2.jpg

Or do you simply inject tangential to the posterior border of the cluster of 3 "stoplights"?

Sure you can do that too. Having posterior spread is sufficient for a successful block.

Or do you inject tangential to the superior border of the cluster?

Some people do it this way as well, but I tend not to do this on my first approach it's much harder to direct your needle inferiorly to pierce through fascia without bending the needle or staying far enough away from surrounding important structures.

In my mind this is incorrect because superior deposition I think will likely lead to anterior spread and increased phrenic nerve blockade.

Phrenic nerve blockade will occur regardless of where you deposit the local anesthetic with the interscalene technique. If you're really worried, you can do a more distal block. Supraclav will generate a phrenic nerve block roughly 50% of the time per classic teaching / data. A suprscapular technique is nice and is sufficient for analgesia, but can be difficult to identify the nerve if you don't have someone showing you initially. But it's traceable back to the C5 nerve root to verify. 5-10 cc around the suprascap nerve will produce enough alagesia for TSA, RCRs etc without a phrenic nerve palsy.