Lumbar RFA motor testing

[Bsb2015]

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Clarification to post: was doing lumbar RFA and had slight anterior thigh twitching at L3 on motor stim but at 2V. When I checked needle placement in lateral and CLO to determine if needle tip in foramen, it looked to be posterior. I had a similar situation in fellowship and the attending lesioned anyways. He was not concerned as the stim occurred at 2V and the leg was not jumping off the table. Didn’t know if anyone thought this was “ok” too. From this thread the risk is far too great and this is not standard of care and I thank you for reassuring me on this. I did inevitably pull back the needle from what my gut was telling me to do.

 

[lobelsteve]

When doing lumbar RFA motor testing, ok to have anterior thigh twitching at the L3 medial branch as long as not past the knee correct?

No. Get a lateral.
Have seen this at L2 when doing GRC RF, but that was in front of the foramen by an inch.

 

[SommeRiver]

When doing lumbar RFA motor testing, ok to have anterior thigh twitching at the L3 medial branch as long as not past the knee correct?

No, it is not okay. At L3, you're clearly describing...nevermind bruh...It's wrong.

 

[thecentral09]

No, it is not okay. At L3, you're clearly describing...nevermind bruh...It's wrong.

What he said

 

[painfree23]

When doing lumbar RFA motor testing, ok to have anterior thigh twitching at the L3 medial branch as long as not past the knee correct?

What pain fellowship did u do?

 

[Ligament]

what voltage?

 

[Bsb2015]

what voltage?

I test up to 2V

 

[Bsb2015]

What pain fellowship did u do?

Obviously not a good one. That’s why I’m asking. The needle was posterior to the foramen. Isn’t the thigh a referral source for pain? There was slight twitching at 2V. Nevertheless I pulled the needle back. My attending in fellowship didn’t care as long as it didn’t go past the knee. Now that I’m out wanted to see what others thought

 

[Bsb2015]

Obviously not a good one. That’s why I’m asking. The needle was posterior to the foramen. Isn’t the thigh a referral source for pain? There was slight twitching at 2V. Nevertheless I pulled the needle back. My attending in fellowship didn’t care as long as it didn’t go past the knee. Now that I’m out wanted to see what others thought

Just started practicing solo. Learning curve exponential from what I hear

 

[Bsb2015]

I test up to 2V

The twitching was at 2V. So probably would expect this?

 

[Bsb2015]

No, it is not okay. At L3, you're clearly describing...nevermind bruh...It's wrong.

The needle was posterior to the foramen. On CLO at Pedicle.

 

[MD87]

Pain referral patterns and motor twitching are different things. Should not have any extremity twitching during motor testing - that's the entire reason to do motor testing - to make sure the leg does not twitch. If you are doing motor testing and seeing leg twitching and still burning, you may as well not motor test at all. Medial branches due not innervate the anterior thigh musculature, only the nerve roots do. Need to reposition the needle if you see leg twitching.

 

[Bsb2015]

Pain referral patterns and motor twitching are different things. Should not have any extremity twitching during motor testing - that's the entire reason to do motor testing - to make sure the leg does not twitch. If you are doing motor testing and seeing leg twitching and still burning, you may as well not motor test at all. Medial branches due not innervate the anterior thigh musculature, only the nerve roots do. Need to reposition the needle if you see leg twitching.

Thanks so much for this!

 

[oreosandsake]

review your myotome map.

the quadriceps are innervated by the femoral nerve which is comprised of fibers from L2-3-4

dermatome map mnemonic was always, "L3 to the Knee"

long story short - the leg should never be moving.

 

[SommeRiver]

The needle was posterior to the foramen. On CLO at Pedicle.

CLO?

No offense but you make me nervous in general.

 

[Ligament]

You can get leg twitching with good cannulae placement, if you have enough voltage. Try it next time; place a needle properly, crank up the voltage. You will often (not always) get leg contractions, in particular around the L3-4 levels.

 

[BobBarker]

Go to the Stryker beginners RF course

 

[bronchospasm]

When doing lumbar RFA motor testing, ok to have anterior thigh twitching at the L3 medial branch as long as not past the knee correct?

Stop. It is not OK.

 

[swamprat]

I can’t believe this question really got asked - how r u just now solo practice ? Do u practice in the USA? Most / if not all pain fellowships end in June..

 

[MD87]

You can get leg twitching with good cannulae placement, if you have enough voltage. Try it next time; place a needle properly, crank up the voltage. You will often (not always) get leg contractions, in particular around the L3-4 levels.

How high of voltage are you talking? If you get twitching in the leg it’s not from the medial branch. Can’t see how getting an extra millimeter of medial branch is worth being deep enough to get leg twitching and possibly frying ventral nerve root fibers... why not pull back? Seems overly risky for an elective procedure when the extra millimeter of MB being burned would give the patient just a little extra time with less pain. Am I missing something?

 

[SommeRiver]

If I place my probe where SIS says to place it I'm not going to get quad twitching, bc if that is possible I think I would have seen that by now (but I haven't). I've done enough at this point that my sample is big enough IMO.

I have gotten really strong buttock and lateral thigh twitching one time on a very tiny Asian man and my lateral showed me about 2mm ventral to the foramen, and that severe stim took off like a rocket at maybe 0.3V or something. Obviously, I adjusted my placement and wouldn't even consider ablating that bc I don't want to hurt anyone during an elective procedure and I'm not trying to get a phone call 4 days after the procedure bc they're having paresthesias.

Paraspinal twitch is fine, but if you're at L3 and you've got a bouncing thigh you're wrong.

Thread starter makes me nervous and this question is one that I have a hard time believing would be asked by a pain fellowship graduate, at least an ACGME graduate. Before anyone cries about that previous sentence...I know there are many fine, if not elite, nonaccredited programs...

 

[cowboydoc]

If I place my probe where SIS says to place it I'm not going to get quad twitching, bc if that is possible I think I would have seen that by now (but I haven't). I've done enough at this point that my sample is big enough IMO.

I have gotten really strong buttock and lateral thigh twitching one time on a very tiny Asian man and my lateral showed me about 2mm ventral to the foramen, and that severe stim took off like a rocket at maybe 0.3V or something. Obviously, I adjusted my placement and wouldn't even consider ablating that bc I don't want to hurt anyone during an elective procedure and I'm not trying to get a phone call 4 days after the procedure bc they're having paresthesias.

Paraspinal twitch is fine, but if you're at L3 and you've got a bouncing thigh you're wrong.

Thread starter makes me nervous and this question is one that I have a hard time believing would be asked by a pain fellowship graduate, at least an ACGME graduate. Before anyone cries about that previous sentence...I know there are many fine, if not elite, nonaccredited programs...

Disagree with first paragraph. I will occasionally see root stimulation at 2v with sis guidelines placement and pull back a mm or 2 to eliminate lower ext. activation, still get paraspinal twitch. Obviously still on the MB, not worth risk to kill the extra mm of it. Needle sometimes looks posterior to where it "should" be in these instances.

 

[callmeanesthesia]

The needle was posterior to the foramen. On CLO at Pedicle.

If the patient is slightly rotated your c-arm may be at full lateral but the image is not a true lateral, which will make one side look falsely deeper and one side falsely shallower.

 

[SommeRiver]

Disagree with first paragraph. I will occasionally see root stimulation at 2v with sis guidelines placement and pull back a mm or 2 to eliminate lower ext. activation, still get paraspinal twitch. Obviously still on the MB, not worth risk to kill the extra mm of it. Needle sometimes looks posterior to where it "should" be in these instances.

I've never had quad stim (that I know of).

 

[painfree23]

General question about RFs - I’ve seen it done both ways but forcmy L2-L4 I usually oblique to 10-15 ipsilateral and bullseye down to the junction of the sap/tp. I’ve seen colleagues start much lower to lay the active tip flat on the nerve (“parallel”) I guess. Thoughts on differences?

 

[Bsb2015]

CLO?

No offense but you make me nervous in general.

I always check lumbar and cervical RFA with CLO To double check needle tip not in foramen

 

[cbest]

Depends what angle you’re using for the CLO. If you see an anterior needle tip placement on lateral for cervical RF, disregard it because you think CLO looks okay, proceed with the burn, and have a bad outcome, that’s gonna be pretty darn tough to fight in court!

 

[Bsb2015]

You can get leg twitching with good cannulae placement, if you have enough voltage. Try it next time; place a needle properly, crank up the voltage. You will often (not always) get leg contractions, in particular around the L3-4 levels.

I think this is what happened. Because the twitching started at 2V. Nevertheless I pulled back the needle and on follow up phone call the patient is not having any complaints.

 

[Bsb2015]

I can’t believe this question really got asked - how r u just now solo practice ? Do u practice in the USA? Most / if not all pain fellowships end in June..

When you carry twins and are forced on bed rest for 8 weeks to then inevitably deliver early, with childcare unexpectedly falling through at the last minute forcing you to stay home longer than you anticipated you graduate late.

 

[Bsb2015]

General question about RFs - I’ve seen it done both ways but forcmy L2-L4 I usually oblique to 10-15 ipsilateral and bullseye down to the junction of the sap/tp. I’ve seen colleagues start much lower to lay the active tip flat on the nerve (“parallel”) I guess. Thoughts on differences?

SIS recommends coming from a caudal approach to be parallel to the nerve rather than perpendicular, but can also depend on what machine you’re using. As you probably already know, with Coolief you can take a perpendicular approach because of the distal projection of the lesion, but with Cosman etc will be more of an elliptical lesion so would need to be parallel to the nerve.

 

[MD87]

Just to reiterate what I think most people are saying - SIS puts out GUIDELINES. They are GUIDELINES because not everyone’s anatomy is exactly the same. It’s not surprising that sometimes an RF probe could look “textbook” and you’d still get extremity twitching. Use the guidelines as guidelines AND use your brain and you won’t hurt anyone.

 

[DrSpine]

Okay, let's just put a rest to this. Any twitching beyond the multifudus/rotators is not good. If you see something in the gluteal region twitching, or lower extremities, STOP, move your needle. I am not sure how you even got there personally, but I'm not going to judge. I will, however, without being mean and giving legitimate constructive advice, tell you to look at an article describing facets/MBBs, and understanding the anatomy of the medial branch that comes off the dorsal rami. There's a great article actually on PubMed for free. I'll see if I can find it, but I had it in my fellowship and did wonders for me. Just aim for the junction of the SAP meeting the TP.

 

[painfree23]

Okay, let's just put a rest to this. Any twitching beyond the multifudus/rotators is not good. If you see something in the gluteal region twitching, or lower extremities, STOP, move your needle. I am not sure how you even got there personally, but I'm not going to judge. I will, however, without being mean and giving legitimate constructive advice, tell you to look at an article describing facets/MBBs, and understanding the anatomy of the medial branch that comes off the dorsal rami. There's a great article actually on PubMed for free. I'll see if I can find it, but I had it in my fellowship and did wonders for me. Just aim for the junction of the SAP meeting the TP.

Can you post that article?

 

[DrSpine]

Can you post that article?

Clinical Anatomy and Measurement of the Medial Branch of the Spinal Dorsal Ramus. - PubMed - NCBI - It's pretty simple and easy. I always just peruse an article on PubMed daily, on random topics dealing with Pain and Interventional Spine. One article a day will get us all far, and discussing these things with others. As well as Podcasts, Pain Podcast is great, as is the PM&R Podcast. I was never the type to crack open a textbook, that was my biggest problem during Residency. It wasn't until I started doing this that I got more into reading and building my knowledge.