Question on Phenol for ablation of lateral femoral cutaneouse nerve

[madhi]

Hi,
I am practicing anesthesia/pain physician in private practice.
Would love to get your advice and suggestions regarding anyone experience using PHENOL for nerve ablation of lateral femoral cutaneous nerve.
If you have used what strength phenol and volume did you inject for ablation.

Thank you
Venu

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[willabeast]

Hi,
I am practicing anesthesia/pain physician in private practice.
Would love to get your advice and suggestions regarding anyone experience using PHENOL for nerve ablation of lateral femoral cutaneous nerve.
If you have used what strength phenol and volume did you inject for ablation.

Thank you
Venu

Suggest not doing it. Phenol is a liquid and travels to unexpected places. Even when it goes to the correct place you can wind up with more neuropathic pain.

 

[thecentral09]

Yea not to keen on the idea. Would suggest Iovera or DRG trial

 

[georgiamd]

Anybody had any luck with pulsed rf

 

[lobelsteve]

Anybody had any luck with pulsed rf

Yes. And one with Nevro after failed RF (history of neurectomy prior to consulting me).

 

[Orin]

I would be hard pressed to pursue chemical neurolytic, but if you must do it, low volumes of 1 - 2 mLs at best with ultrasound guidance. Medial spread onto the femoral would be my major fear.

I have had little luck with pulsed RF
It's an easy PNS target to capture but normally I have had good response to a block in the setting of ongoing PT/weight loss/lifestyle changes

 

[callmeanesthesia]

Agree with concerns about spread with chemical neurolysis. I did one thermal RF. Guy had failed weight loss, antineuropathics, and nerve block with steroid. Counseled him extensively about permanent numbness, risk of worsening pain. Did it under ultrasound, fortunately had a beautiful view of the nerve. Did sensory stim to confirm LFCN distribution paresthesia, then numbed and did 3 or 4 zones of ablation 80 deg, 90 sec, I think). He had pretty much total relief, and was able to get rid of his cane. That was over a year ago and I haven’t seen him since a couple follow ups, so I’m assuming it’s still working.

 

[painfree23]

Agree with concerns about spread with chemical neurolysis. I did one thermal RF. Guy had failed weight loss, antineuropathics, and nerve block with steroid. Counseled him extensively about permanent numbness, risk of worsening pain. Did it under ultrasound, fortunately had a beautiful view of the nerve. Did sensory stim to confirm LFCN distribution paresthesia, then numbed and did 3 or 4 zones of ablation 80 deg, 90 sec, I think). He had pretty much total relief, and was able to get rid of his cane. That was over a year ago and I haven’t seen him since a couple follow ups, so I’m assuming it’s still working.

do you have pictures or resources for how to do this under US?

 

[callmeanesthesia]

do you have pictures or resources for how to do this under US?

Ultrasound-Guided Lateral Femoral Cutaneous Nerve Block - NYSORA

The lateral femoral cutaneous nerve (LFCN) divides into several branches innervating the lateral and anterior aspects of the thigh.Indications are postoperative analgesia for hip surgery, meralgia paresthetica, and muscle biopsy of the proximal lateral thigh.

www.nysora.com

As for ablating it, I pretty much made it up as I went along. Burn a little, move the needle a little cephalad and burn again, a little distal and burn again. The needle lies perpendicular to the nerve with the textbook approach so I did multiple to provide more reliable destruction. You could probably do an out of plane approach though and lay it parallel (didn’t occur to me at the time or I would have)

 

[soccrwz]

Isn't it pretty superficial, are you worried about burning through the skin?

 

[painfree23]

where

Yes. And one with Nevro after failed RF (history of neurectomy prior to consulting me).

where were the nevro leads?

 

[callmeanesthesia]

Isn't it pretty superficial, are you worried about burning through the skin?

Not in patients who get meralgia paresthetica... There was ample subcutaneous tissue.

 

[painfree23]

Not in patients who get meralgia paresthetica... There was ample subcutaneous tissue.

Lol

 

[lobelsteve]

where

where were the nevro leads?

Spanning T9-10 and T10-11 disc spaces. Lowest part of lead was mid T11.

 

[Ducttape]

I'm not sure I would do phenol neurolysis for meralgia paresthetica.

the clinical course tends to be one of gradual remission or resultant anesthesia to the area.

outside of blocks, weight loss, activity changes, ive done a few pulsed RFA with some result. SCS or DRG seems reasonable. the permanence and potential local damage from phenol seems too aggressive...


time takes care of the pain...

 

[painfree23]

Spanning T9-10 and T10-11 disc spaces. Lowest part of lead was mid T11.

Did you intraop test ?

 

[lobelsteve]

Did you intraop test ?

That's not how 10k stim works.

 

[painfree23]

That's not how 10k stim works.

So how’d u decide on this level vs T8-T10?

 

[lobelsteve]

So how’d u decide on this level vs T8-T10?

That's where it goes.

 

[Orin]

The leads go there or it gets the hose again...

 

[SommeRiver]

In fellowship "we" put a Boston stim lead on an ilioinguinal neuralgia. Didn't work. As I sit here I can't remember what we did with the IPG. I didn't participate in the case...I just watched.

 

[joshmir]

You can also ask a peripheral neurosurgeon to divide pouparts/inguinal ligament to decompress the nerve. N=2, both great results

Also ask them to clip nerve and bury end in nine or wrap with vein to prevent neuroma sprouting.

I think if you can isolate it in U/S and confirm that your 1cc doughnut of local blocks it then please convince me why 1cc of phenol or alcohol is dangerous if not Superficially subQ or close to femoral nerve. Especially if you ask them to lay still for 15 minutes afterwards.

 

[painfree23]

In fellowship "we" put a Boston stim lead on an ilioinguinal neuralgia. Didn't work. As I sit here I can't remember what we did with the IPG. I didn't participate in the case...I just watched.

U put it on the lfc or in the spine?

 

[SommeRiver]

U put it on the lfc or in the spine?

I stood there while an attending put one on the ilioinguinal nerve.

BTW - Let me add I have no idea why this pt chose to do this, or why the attending did it when traditional SCS is available. DRG was barely off the ground at that point in time.

Dorsal column stimulation is more than adequate for something like a lower extremity neuralgia, whether you do HF10, Burst, or standard paresthesia circa 1995.