Confused about nerve conduction studies.

I'm confused about nerve conduction studies-- I've recently had one on my neck and shoulder muscles to help determine the cause of a two year long pain syndrome. ( i am a no longer practicing dentist) On the one hand, I was told that these studies can detect nerve root impingement or decreased innervation to muscles before the patient even realizes there is something wrong-- the tests are apparently that sensitive.

On the other hand, I was also told muscle spasm and pain could indeed be from entrapped nerves (or nerve roots) that slip under the detectability of these tests. so, what's the real deal??

Will issues that are strictly myofascial show up on these tests???

Could a nerve root still require surgical intervention even if this test was negative for a radiculopathy?? ie, can someone get pain from a nerve root impingement and still have a negative test??  

I had nerve root blocks that seemed to be diagnostic, but if the problem(s)were distal to the block (ie in the neck musculature for instance) wouldn't these blocks be positive even though the entrapment (or myofascitis) is not of the root itself??

I had both my shoulders scoped, and I had a c5/6 c6/7 minimally invasive foraminotomies--- no help.    sorry for so many questions.  I'm just trying to get the facts straight.

Symptoms are pain/tightness -- sometimes into chest muscles/always in neck, posterior shoulders and sometimes anterior shoulders. Some relief w/ stretching.  

Thanx again,

[CCF-Neuro-M.D.-PW]

Nerve conduction studies are a limited test in neuromuscular neurology, even more limited if done and interpreted without a needle EMG.

NCS are quite limited also in assessing upper limb nerve problems as these nerves/muscles are technically harder to stimulate. The main are of detection of problems before symptoms in in carpal tunnel syndrome, a pinched nerve at the wrist where NCS are most effective. NCS are not good for nerve root prolems also where needle EMG is more effective.
NCS or EMG does not provide a clinical diagnosis either and must be used as an adjunctive test along the with history and exam which provide 90% of the diagnosis.

There may be negative NCS and a nerve root problem as above. Nerve root blocks are not an accepted way of diagnosing or localizing a nerve problem as you state above. From the description of your symptoms, it does not sound like a nerve or nerve root problem on the surface, although a needle EMG or neck MRI may be useful to exclude a mid cervical nerve root problem, ie the cause may be musckuloskeletal.

Good luck

[mike1105]

i should mention that MRI and CT MYelogram showed disc protrusions, stenosis (Moderate) and Moderate foraminal stenosis in the c5/6/7 areas. The Myelogram showed that the Right c5/6/7 foramens did not allow the solution to penetrate. I do also get pain in the arm muscles sometimes. If the surgery did not help, should I conclude that it probably did not address more distal,muscular sources of pain?