Combined Sensory Index - CTS

[drusso]

For those of you who trained at UW or use the combined sensory index for CTS studies, can you walk me through it. I've read one of Larry Robinson's papers and attended one of his workshops at the Academy, but I'd like to hear how you actually use it in your practices.

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[SSdoc33]

there are nuances that im sure someone will correct, but this is how i understand it:

-do 3 sensory studies: the radial/median difference to the thumb, the transcarpal using median/ulnar, and the ring finger using median/ulnar. add up the changes as compared to the median conductions (for ex: if the transcarpal showed a median latency of 2.0 and the ulnar showed 1.5, then you'd have a 0.5 difference). if the sum is > 0.9, then you've got CTS. needle for axonal damage.

apparently its the most sensitive for CTS when there is a doubt or if ther eis a mild case. still need to do needle to deteremine axonal damage. also, there have been a few more recent papers (by robinson i think) that looked at which of the three studies to do first and the best algorythm. i dont remember exactly, but i think you do the ring finger first and then if the difference is greater than a certain number you stop. not 100% sure on that, though

 

[SSdoc33]

i dont really use it, though. it seems a bit cumbersome and doesnt add much. only rarely when the diagnosis is really borderline.

 

[neglect]

i dont really use it, though. it seems a bit cumbersome and doesnt add much. only rarely when the diagnosis is really borderline.

If you cast the net wide enough, you'll eventually find something. Personally, if the median sensory and motor are normal, then I find comparison studies useful only in the setting of clinical CTS. Otherwise, let's face it, these are the mildest cts cases and will likely get better no matter what.

 

[axm397]

We work with over 10 different attendings over the course of our EMG months and fortunately or unfortunately, they all have very different styles.

The one that trained at UW likes to start his CTS work up with median & ulnar motor (APB and ADM) - so if there's abn there, might expect some sensory abn and perhaps even absent sensories so don't waste time hunting for them.

Then, he goes on to median and ulnar sensory to the 4th digit - if there's more than 0.9 difference there, bingo stop right there. if not, go on to "numb thumb" - radial and median sensory to the thumb. if the sum of the difference is still not 0.9, then do the transcarpals.

 

[spondy14]

just curious as someone can justify to bill that many sensory nerves, or are they just billing for 3 when doing all three exams?

 

[db36jp78]

I actually asked one of our senior techs about this and I was told that you can not bill for a full 6 sensory studies when using the CSI-you can only bill for 3.

 

[spondy14]

I actually asked one of our senior techs about this and I was told that you can not bill for a full 6 sensory studies when using the CSI-you can only bill for 3.

That sounds more reasonable than 6.

 

[Disciple]

Typically, I'll do the Med/Uln motor/sens

If the it doesn't show and the presentation suggests CTS I'll go to the palmar sensory comparison.

If it still doesn't show, then Med/Rad (thumb) and Med/Uln (Dig III) and add up the 3 values.

Useful prior to surgical eval or establishing a diagnosis for a comp case/disability rating.