Root search

[Myofascist]

I am very excited about this new forum as EMG/NCS fascinates me more than many of the other facets (no pun intended) of PM+R. So thanks for starting this up.
When it comes to UE and LE root searches for radiculopathy I am wondering what people are doing in other parts of the nation. So i wanted to start a thread regarding this and get some thoughts. Obviously the search can change mid-exam depending on abnormalities but if all is normal what do you all check?

UE: delt, triceps, biceps, PT, EIP/EDC, and FDI
LE: TA, MG, TP or PL, quad, glut med or TFL

---

Members don't see this ad.

 

[axm397]

again, with 10+ different attendings doing EMGs - have a wide variety - some as little as 4 muscles if they're all normal they stop, and others with 6 including paraspinals. (obviously, no paraspinals if hx surgery)

most of the time we do:

UE: deltoid, triceps, biceps, PT/FCR, FDI +/- FCU or paraspinals add on diff muscles depending on pt's complaint

LE: VMO/VL, TA, MG, PL, glut med/TFL or glut max or short head biceps femoris (depends on what we find distally), and +/- paraspinals.

 

[PMR 4 MSK]

My UE screen, assuming normal NCV's - Delt, Triceps, biceps, PT and FDIM. If CTS+, add APB, other problems encountered, add onto that.

My LE screen - Quad, Tib Ant, Med Gastroc, FDIM or AH, EDB

 

[caedmon]

This are some quotes from studies done by Dr. Dillingham at MCW. He recommends six in the leg and six in the arm (including paraspinals), emphasizing covering all root levels, and minimizing harm.

For lumbar:
"When paraspinal muscles were one of the screening muscles, four-muscle screens identified 88–97% of the radiculopathies, five-muscle screens identified 94–98%, and six-muscle screens 98–100%. When paraspinal muscles were not part of the screen, identification rates were lower for all screens, and eight distal muscles were necessary to identify about 90% of the radiculopathies"

-T.R. Dillingham, T.D. Lauder and M. Andary et al., Identifying lumbosacral radiculopathies an optimal electromyographic screen, Am J Phys Med Rehabil 79 (2000), pp. 496–503

For cervical:
"When paraspinal muscles were one of the screening muscles, five muscle screens identified 90% to 98% of radiculopathies, six muscle screens identified 94% to 99%, and seven muscle screens identified 96% to 100%. When paraspinal muscles were not part of the screen, eight distal limb muscles recognized 92% to 95% of radiculopathies"

-T. Lauder and T.R. Dillingham, The cervical radiculopathy screen optimizing the number of muscles studied, Muscle Nerve 19 (1996), pp. 662–665

This work emphasizes the fact that without evaluating paraspinal muscles, one must needle more distal muscles to be confident that there is no radiculopathy. Also the study showed that as long as you were covering all root levels, there was really no difference in the muscles selected.

As for me:
LE screen- ta, med gastroc, vastus medialis/lateralis, TFL/Gmed, GMax, paraspinals
UE screen- FDI (APB/opponens if CTS), pronator, biceps, triceps, deltoid, paraspinals
If there is clearly clinical carpal tunnel syndrome with NCV to confirm, I won't do cervicals.

 

[PMR 4 MSK]

My only arguement against Dillingham on this is what to do with isolated paraspinal PSWs or Fibs. It cannot help you isolate a level with certainty, and by itself is of questionable significance, and then also makes you go back to the limb to needle some more, which I have rarely found fruitful.

 

[axm397]

we just had that case scenario:

a woman with MS - in rehab for new lesions - with 1 wk hx of LBP w radic pain into L Lower Limb (L5 distribution mostly). NCS normal x absent superficial peroneal (sural was normal). EMG normal for VMO, TA, MG, PL, Glut Med. Clean for mid lumbar paraspinals. 1+ PSW in lower lumbar paraspinals.

I thought 1 wk would be too soon but primary team wanted to make sure nothing at baseline related to MS or some other neuropathy. We told them to have pt come back in several weeks if want definitive dx of lumbar radic. Called results "probable" acute lower lumbar radic. not sure what to do w absent superficial peroneal - I guess if DRG is intercanal sensory can be affected....

It is tough

 

[SSdoc33]

i wouldnt call that a "probable" radic. i also wouldnt make much of the absent superficial peroneal. if it was a radic, the sensories would be normal anyway. the paraspinals would probably be the first to show up if this just started recently, but an isolated needle abnormality can be normal.

Haig has a great article on paraspinal mapping that might help this.

 

[axm397]

Yeah - I wasn't sure about calling it either but the mid lumbar paraspinals was so clean and in contrast the PSWs in the lower lumbar paraspinals were very striking. We said "probable" precisely because it's an isolated finding. The superficial peroneal being abnormal and her distribution of pain made us call it. I think if it was just the paraspinals we may not have called it.

In a radic, sensories are not necessarily normal. that's why we said the DRG could be intraspinal.

Author: Levin, K H.

Institution Cleveland Clinic Foundation, Department of Neurology, OH 44195, USA.

Title L5 radiculopathy with reduced superficial peroneal sensory responses: intraspinal and extraspinal causes.

Source Muscle & Nerve. 21(1):3-7, 1998 Jan.

Abstract Thirteen patients were retrospectively identified with the electrodiagnostic pattern of combined L5 radiculopathy by needle electrode examination, and abnormality of the superficial peroneal nerve (SPN) sensory nerve action potential (SNAP) amplitude. To have combined L5-derived sensory and motor axon loss, lesions must be localized at or distal to the L5 dorsal root ganglion (DRG), but also proximal to the sacral plexus. Six patients had evidence of an active intraspinal canal (ISC) lesion, 3 had diabetes, and 4 had nonspecific causes. The ISC localization in at least 6 of our cases is counter to the commonly held electrodiagnostic dogma that L5 radiculopathy spares the SPN SNAP, but recent anatomic studies confirm the ISC location of up to 40% of L5 DRG. Thus loss of the SPN SNAP does not exclude ISC lesions.

 

[SSdoc33]

gotcha. that makes a lot more sense.

 

[PMR 4 MSK]

I've seen many MRIs with HNPs extending far lateral into the neuroforamina, impacting the DRG. There is some variability in how far out the DRG is. Makes sense that those pts would have impaired sensory responses.

However, in the case presented, I would not expect wallerian degeneration to have advanced that far south in 1 week. Partly depends on her age - past 50, many/most have absent peroneal SNAPs. Plus, MS could attack peripheral nerves.

Wasn't an MRI done?