F Waves

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topwise

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Sorry, this isn't a case, but I was wondering if you expert EMGers could give me your thoughts on this:

How often do you do F waves on your patients?

When do you do them and why?
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topwise said:
Sorry, this isn't a case, but I was wondering if you expert EMGers could give me your thoughts on this:

How often do you do F waves on your patients?

When do you do them and why?
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I do them much of the time on distal testing - median, ulnar, tibial and peroneal. I'm looking for either info indicating agreement with the distal findings, and seeing if anything proximal shows up in the shadows. In addition to latencies, you can also look at how often they show up, and how variable the are in latency and morphology. They are easy to do and occasionally yield information that helps.

Others will disagree and say they don't yield enough to justify them, they are non-specific (very true), etc.

I've tried looking for them with radial motors - only find them about 25% of the time. I've tried looking for them with proximal stims - such as brachial plexus, peroneal to tib Ant, etc - rarely find them.
 
What they teach you:

F-wave latencies are very reproducible. Good for monitoring disease progression.

Good for examining proximal segments of nerves. Presence of a-waves, noted during F-wave testing, indicates branched motor axons, usually signifies presence of a neuropathy of some sort. May be abnormal in multilevel radics, or polyradics, not usually in a single level radic. Delayed or absent F-waves may be the earliest abnormality noted in things like AIDP or MMN w/ CB.

Practically speaking though, for most of what the average EMG’er sees, F-waves don’t add much more clinical utility over the standard NCS/EMG. Not very specific, as PMR 4 MSK mentioned.

That being said, I do them (median, ulnar, peroneal, tibial) on a regular basis. Where I practice, I see lots of weird stuff, and occasionally I do find things on F-wave testing that come in handy. Never did the radial though, I'll have to try it sometime.
 
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Thanks for your answers.

Preston & Shapiro seems to do F Waves in every case example. I'm just wondering what an F wave adds (if anything) to the study if you're doing a CTS study that's positive.
 
topwise said:
Thanks for your answers.

Preston & Shapiro seems to do F Waves in every case example. I'm just wondering what an F wave adds (if anything) to the study if you're doing a CTS study that's positive.
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$$$$ is what it adds.....
 
Hehe.... that's for sure. Anything else, though? P&S seem to think it's worth doing.
 
Anyone here had trouble with insurance companies not paying the motors w/o F wave when billed with motors w/F (95900 and 95903 together)? They say that were are "unbundling", such as if I billed 2 units of 95900 and 2 of 95903, that we didn't do seperate nerves. Then we have to appeal, send in the report and seperate justification so someone with a high-school education knows why we did what we did.
 
PMR 4 MSK said:
Anyone here had trouble with insurance companies not paying the motors w/o F wave when billed with motors w/F (95900 and 95903 together)? They say that were are "unbundling", such as if I billed 2 units of 95900 and 2 of 95903, that we didn't do seperate nerves. Then we have to appeal, send in the report and seperate justification so someone with a high-school education knows why we did what we did.
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59 modifier should clear that up..
 
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