Electrodiagnosticians/ Electromyographers, please help with 2 questions

[outpatientcare]

If you want to give input please do!

1) after a "whiplash" injury/ MVA, hit from behind- why is it common to have symptoms in an ulnar nerve distribution and would there be changes on NCS/EMG? I read this in pocketpedia and never paid it any mind until another doc presented such a case to me. I'd be thinking C8-T1 nerve roots but pocketpedia doesn't say that, it says ulnar nerve distribution and apparently this patient had such symptoms, i.e. not C8-T1 and not TOS symptoms, but ulnar nerve. Thanks!

2) Patient with ulnar nerve distribution symptoms (completely separate from case 1). If the ulnar sensory nerve at the wrist looks stellar, e.g. amplitude 40 and peak latency 2.8, and the ulnar motor amplitude at the wrist, below elbow, and above elbow all look great, e.g. all 13, how likely is it that a drop in conduction velocity across the elbow is real versus technical error? Lets say the DUC is stellar also for whatever that is worth. Can one call this an ulnar neuropathy at the elbow effecting the motor fibers or would this scenerio be virtually impossible and more likely technical error whether the technician or even patient anatomy. Thanks!

I looked through available text, limited articles, and did some googling and could not find anything.

Any input would be greatly appeciated.

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[Taus]

1) ? Myofascial referral pattern

2) Could definitely be real- neuropraxia/ myelin injury without conduction block or axon loss. How much of a drop? Were sensory studies done across elbow- should have slowing also

If you want to give input please do!

1) after a "whiplash" injury/ MVA, hit from behind- why is it common to have symptoms in an ulnar nerve distribution and would there be changes on NCS/EMG? I read this in pocketpedia and never paid it any mind until another doc presented such a case to me. I'd be thinking C8-T1 nerve roots but pocketpedia doesn't say that, it says ulnar nerve distribution and apparently this patient had such symptoms, i.e. not C8-T1 and not TOS symptoms, but ulnar nerve. Thanks!

2) Patient with ulnar nerve distribution symptoms (completely separate from case 1). If the ulnar sensory nerve at the wrist looks stellar, e.g. amplitude 40 and peak latency 2.8, and the ulnar motor amplitude at the wrist, below elbow, and above elbow all look great, e.g. all 13, how likely is it that a drop in conduction velocity across the elbow is real versus technical error? Lets say the DUC is stellar also for whatever that is worth. Can one call this an ulnar neuropathy at the elbow effecting the motor fibers or would this scenerio be virtually impossible and more likely technical error whether the technician or even patient anatomy. Thanks!

I looked through available text, limited articles, and did some googling and could not find anything.

Any input would be greatly appeciated.

 

[outpatientcare]

Thanks for the reply.

I am an attending. Did you/ anyone catch in Pocketpedia about "whiplash" injury and ulnar nerve distribution symptoms. It didn't come to the front of my mind until I heard about the case. Wish I knew the page number.

About the "cubital tunnel syndrome" I wonder because I have never seen that with carpal tunnel. I have never heard of a case where there were no sensory nerve changes with presense of motor abnormalities (I have seen normalized NCS with abnormal needle study post release).

 

[lobelsteve]

Thanks for the reply.

I am an attending. Did you/ anyone catch in Pocketpedia about "whiplash" injury and ulnar nerve distribution symptoms. It didn't come to the front of my mind until I heard about the case. Wish I knew the page number.

About the "cubital tunnel syndrome" I wonder because I have never seen that with carpal tunnel. I have never heard of a case where there were no sensory nerve changes with presense of motor abnormalities (I have seen normalized NCS with abnormal needle study post release).

C6-7 disc referral can include ulnar hand.

 

[Gauss]

how severe of a drop? Are the waveforms altered? Did you do inching technique or 10cm? How does it look on the contralateral side?

 

[RUOkie]

About the "cubital tunnel syndrome" I wonder because I have never seen that with carpal tunnel. I have never heard of a case where there were no sensory nerve changes with presense of motor abnormalities (I have seen normalized NCS with abnormal needle study post release).

I see that all the time. Sometimes with denervation on EMG, sometimes not. I always do an inching study when I find slowing across the elbow, and I keep in touch with the surgeons. There is almost always an indentation of the myelin right where the inching study said it should be.

 

[SSdoc33]

to the OP, try one question at a time next time. you'll confuse yourself.

with a whiplash injury, theoretically, you could see a radiculopathy on EMG at any level. however, in practice, seeing any abnormalitites on EMG is very rare.

the "ulnar distribution" symptoms may be secondary to chemical radiculitis, segmental dysfunction, myofascial pain, or a combo.

best thing to look for in ulnar neuropathy is a drop in ulnar amplitude (esp. motor) across the elbow as well as spont activity in FDI and ADM. that way, you wont confuse yourself with those pesky measurements

 

[PMR 4 MSK]

Whiplash can certainly cause damage to the cervical cord, DRG or peripheral nerve, but these are quite uncommon without pre-existing stenosis or significant spondylosis, or without HNP. A pure whiplash injury would not be expect to cause ulnar nerve injury, as the ulnar nerve is formed until out in the shoulder region (terminal brachial plexus). If the ulnar nerve is the culprit, the damage is, by definition outside of the neck.

If it is just sensory symptoms/paresthesias, it could be referred, myofascial or similar.

For question #2, you can get pure demylination of the ulnar nerve at the elbow. Amplitudes that high in the elbow (13) are rare, but if you have a more acute injury, you can see that - low NCS without amplitude drop.

 

[outpatientcare]

Thanks for all of the replies to the original post. I greatly appreciate them.

About case 1: I found what I was referring to in Pocketpedia 2003 (Choi)- the black review book many of us are familiar with- page 19- The main point of interest is the fact that it distinctly says "ulnar nerve" distribution. I never paid it any mind whatsoever until I heard the case. In my mind, why on earth not say C8 or C8-T1 or something that would point to nerve roots as we would think as oppose to "ulnar nerve distribution" which I think can be confusing. Myofascial pain pattern is a very interesting thought though. At any extent, it's just a review book.

About case 2: It's not at all a real case but I have run into this, especially when I was a resident where the patient presentation smelled like an ulnar mononeuropathy at the elbow but the sensory studies would come out looking great with a drop in motor conduction velocity at the elbow. I often wondered if this was just an error with my measurements.

I also wondered because with my CTS cases I always see sensory NCS abnormalities when I find median motor NCS abnormalities (i.e. I have never come across a case of clear median mononeuropathy/ CTS where there were abnormalities with the motor NCS with the sensory NCS looking stellar.

I have not done much in regards to inching studies at the elbow so I need to consider that more.

Thanks

 

[RUOkie]

I also wondered because with my CTS cases I always see sensory NCS abnormalities when I find median motor NCS abnormalities (i.e. I have never come across a case of clear median mononeuropathy/ CTS where there were abnormalities with the motor NCS with the sensory NCS looking stellar.

I have not done much in regards to inching studies at the elbow so I need to consider that more.

Thanks

1) Regarding Motor only CTS. Do enough EMG's an you will see that. Especially (this is anecdotal, not published) in construction workers, and people exposed to vibration.
2) Inching studies are wonderful ways to separate you from the people using techs to do their NCS. The surgeons love that information once they learn how to use it. It is your job to educate them, and see your business grow.

 

[bedrock]

About case 2: It's not at all a real case but I have run into this, especially when I was a resident where the patient presentation smelled like an ulnar mononeuropathy at the elbow but the sensory studies would come out looking great with a drop in motor conduction velocity at the elbow. I often wondered if this was just an error with my measurements.

This happens somewhat frequently with mild ulnar neuropathy at the elbow, agree with rookie that you can rarely see this with median at wrist, but it's more common with mild ulnar neuropathy.

2) Inching studies are wonderful ways to separate you from the people using techs to do their NCS. The surgeons love that information once they learn how to use it. It is your job to educate them, and see your business grow.

Very location dependent. Most private practice ortho docs don't care about inching studies, so do, but most orthopedists don't care.

 

[mdvol]

for question 1) how about lower trunk brachial plexus stretch?

 

[DistantMets]

My advice with UNE (as with all of EMG/NCS) is to err on the side of undercalling, or at least choose your words carefully. For example, If I get a ~10m/s drop in CV on the motor at the elbow with normal amplitude throughout on both the ADM and FDI study, with normal sensory and normal needle. I call it "borderline" rather than "mild" and recommend a repeat study down the road. "Mild" equals cut all to often to some surgeons. Don't be afraid to do another run of your NCS with fresh measurements. Ulnar nerve surgery is just not that great. If the patient is miserable, I'll take some extra time to ultrasound the ulnar nerve at the elbow looking for a sizeable change in area. Practice needling the FDP as well, if abnormal, it tells you the lesion is not at the wrist.

To improve your measurement, don't flex the elbow past 90 degrees, check for a subluxing nerve by holding pressure with a finger on the epidconyle and flex the elbow, you might feel pressure under your finger and the nerve flipping across, possibly with a parathesia illicited, as you let go. If they have a fat flabby arm your measurement with suck regardless and you should really not overcall.

 

[PMR 4 MSK]

My advice with UNE (as with all of EMG/NCS) is to err on the side of undercalling, or at least choose your words carefully. For example, If I get a ~10m/s drop in CV on the motor at the elbow with normal amplitude throughout on both the ADM and FDI study, with normal sensory and normal needle. I call it "borderline" rather than "mild" and recommend a repeat study down the road. "Mild" equals cut all to often to some surgeons. Don't be afraid to do another run of your NCS with fresh measurements. Ulnar nerve surgery is just not that great. If the patient is miserable, I'll take some extra time to ultrasound the ulnar nerve at the elbow looking for a sizeable change in area. Practice needling the FDP as well, if abnormal, it tells you the lesion is not at the wrist.

To improve your measurement, don't flex the elbow past 90 degrees, check for a subluxing nerve by holding pressure with a finger on the epidconyle and flex the elbow, you might feel pressure under your finger and the nerve flipping across, possibly with a parathesia illicited, as you let go. If they have a fat flabby arm your measurement with suck regardless and you should really not overcall.

I don't find any treatment that works well for the majority of cubital tunnel patients. I don't believe steroid injections help, but Imma start doing them under US to see if it makes a difference.

For size differences of nerves on US, there is controversy over whether it really matters for the median nerve at the carpal tunnel. There is less evidence of it's significance on the ulnar nerve at the elbow.

Also, if you truely believe or are concerned they are subluxing, you can easily see it doing so on US.

 

[RUOkie]

I don't find any treatment that works well for the majority of cubital tunnel patients. I don't believe steroid injections help, but Imma start doing them under US to see if it makes a difference.

For size differences of nerves on US, there is controversy over whether it really matters for the median nerve at the carpal tunnel. There is less evidence of it's significance on the ulnar nerve at the elbow.

Also, if you truely believe or are concerned they are subluxing, you can easily see it doing so on US.

provided you do not press too hard on the transducer.

Regarding cubital tunnel, the literature does NOT demonstrate that size matters at all of the Ulnar N. Marko Bodor gave a great review of that literature at the UE-US course this past week.

 

[Finally M3]

best thing to look for in ulnar neuropathy is a drop in ulnar amplitude (esp. motor) across the elbow as well as spont activity in FDI and ADM. that way, you wont confuse yourself with those pesky measurements

I like your thinking. This is my approach as well.

DUC, even during residency when I hunted for it, was spotty enough and enough variance on if it left above/below Guyon's that I don't bother anymore.

MCV across the elbow with decreased amplitude (primarily motor, sometimes sensory) with needle of FDP, ADM, FDIH. Rest of needle should be able to r/o superimposed C8 radic.

If I'm really confused, I will put in my conclusion; "Consider U/S or MRI imaging to localize lesion". Have been to a couple of lectures by Kimura where he really advocates use of inching but never have really tried it.

 

[PMR 4 MSK]

I like your thinking. This is my approach as well.

DUC, even during residency when I hunted for it, was spotty enough and enough variance on if it left above/below Guyon's that I don't bother anymore.

MCV across the elbow with decreased amplitude (primarily motor, sometimes sensory) with needle of FDP, ADM, FDIH. Rest of needle should be able to r/o superimposed C8 radic.

If I'm really confused, I will put in my conclusion; "Consider U/S or MRI imaging to localize lesion". Have been to a couple of lectures by Kimura where he really advocates use of inching but never have really tried it.

Inching can work if you are fastidious about it. It's technically demanding. Too often, I have found it splitting hairs.

 

[RUOkie]

Inching can work if you are fastidious about it. It's technically demanding. Too often, I have found it splitting hairs.

The same can be said for most electrodiagnostics. If you inch every ulnar neuropathy, it gets easier. After >9k studies, inching is not that hard.