EMG in Neck and Arm Problems - Part V

Long thoracic nerve vs. dorsal scapular in asymmetric scapulae Top

Question

I have an asymmetric scapula that is low and prominent at the inferior medial edge and looks farther away from the spine than my other scapula and causes me lots of pain and problems. My EMG showed a single repetitive discharge from the LTN at the end of the test. The tester thought that clinically it didn't seem to account for the way my scapula looked. I also showed moderate to severe weakness in all muscles tested on the right side of my back-scapular region. My rhomboids and levator were also tested. This has been ongoing for 2 years and I am quite impaired by the problem.
I really need help to figure this out. I am not improving and although my scapula is not a typical textbook example of winging I have pain and weakness down the arm, and pain and looseness around the scapula.
Could I have some dorsal scapular nerve injury too that is simply hard to find. My trapezius also looks a little sunken in on that side. Thanks

Answer

Sorry for delay in replying. Now, winging of scapula can be due to long thoracic nerve or dorsal scapular injury. It depends on findings clinically and EMG. However, in your case you mentioned that trapezius is sunken a little, this muscle is not supplied by either nerves. This is against those possibilities. I think good neurological examination should help, but we should keep in mind that injury of nerves not the only cause of winging scapula. All the best.

Axonal Peripheral neuropathy        Top

Question

Need help understanding EMG report - please. Ending comment states abnormal EMG exam & nerve conduction studies. Two problems noted - 1) Mixed motor-sensory - but principally sensory neuropathy. With decreased amplitude & normal latencies - axonal in form. Changes shown by low-amplitude conductions and on motor side by marked increase in irritability distally bordering on denervation. Patient also has bilateral carpal tunnel syndrome with prolonged median sensory & palmar latencies. Can anyone put this in non-medical - simple English terms? Having problems understanding what is meant by "decreased amplitude & normal latencies" and also irritability distally bordering on denervation. Is this bad? Also, does anyone know where you can obtain standard nerve msec readings - for instance I have 4.1 msec for sensory distal latency - how bad is that? I really appreciate any and all help on how to understand what is going on.

Answer

You are not alone in your confusion in interpreting this report. You definitely need to post more of the data (amplitudes, latencies and conduction velocities, as well as needle EMG results) to be more definitive. To answer partially...
1. Your nerves are built somewhat like a piece of wire, an insulating outer layer (myelin) and a bunch of small wires on the inside (axons). In general, if the myelin is being affected by some process, the conduction velocity will be slow and latencies will be prolonged. If the inner wires (axons) are being affected, the amplitudes of the response recorded are decreased. The description would indicate that you have some widespread process affecting the axons of the sensory nerves, although without the data I hesitate to say this.
2. The sentence about "marked increase in irritability ..." makes no sense. Sounds like a reference to the EMG study (the needle part) but I can't tell.
3. Normal values are dependent on many factors (technique, temperature etc), so again this is hard to comment on. Generally, 4.1 ms across a 14 cm distance (a typical distance for a distal sensory latency) would be mildly prolonged (but some reports would call this normal).
Confused yet? Again, need more data to be more definitive. Hope this helps.

Comment

Thank you very much for your initial response. I didn't know how much info to give as I am new to all of this but in a nut shell here is the report:
Results: Upper extremities-Irritability was normal, without fibrillations or positive sharp waves.
Lower extremities - Irritability was markedly increased in the intrinsic muscles of the feet with runs of positive sharp waves on needle insertion, but none were sustained with the needle at rest. Irritability elsewhere was normal.
Nerve Conductions: Right Median Nerve - Motor distal latency at 8cm was 4.1 msec; Sensory distal latency at 13cm was 4.1 msec; Palmar sensory latency at 8cmm was 2.6 msec
Left Median Nerve - Motor distal latency at 8cm was 3.0 msec; Sensory distal latency at 13cm was 4.2 msec; Palmar sensory latency at 8cmm was 2.8 msec
Right Ulnar Nerve - Motor distal latency at 8cm was 3.1 msec; Sensory distal latency at 13cm was 2.9 msec
Left Ulnar Nerve - Sensory distal latency at 13cmm was 3.1 msec
Sensory responses for the ulnar nerve were moderately reduced in amplitude and median responses were markedly reduced in amplitude.
Right Sural Nerve - Sensory distal latency at 14cm was 4.0 msec
Left Sural Nerve - Sensory distal latency at 14cm was 3.7 msec
These values were obtained only by the use of averaging techniques and were markedly reduced in amplitude.
The balance were the comments mentioned initially. The patient is my husband and he has been exposed to chemicals at work which we believe is the cause of the peripheral neuropathy as he is not diabetic and has never been a heavy drinker. He is 49 and has been very healthy his entire life - until now. He works construction so has worked hard and while thin is very muscular. He does have allergies (dust, grass, etc) but has also been found to have a 35% loss to his lungs. This was a 2nd opinion doctor required by the workers compensation carrier for a case that has gone on since July 1999. In seeing the various docs we are told that he has nerve damage and not much treatment other than for pain is available. His doc has told him that he is 100% disabled due to the constant pain in hands, arms, legs & feet and nothing to rehab him into. Obviously the W/C carrier wants to fight that diagnosis. The part of this 2nd opinion report that worried me the most was the denervation comment. From the tests in Oct 1999 & Feb 2000 it looks like the condition is getting worse as the numbness/loss of feeling is going higher up the arms and legs. Any insight you can give me is appreciated. (Sorry for the length of this note.) God Bless you!

Possible double crush to ulnar nerve         Top

Question

Two years ago this May 17th 2001. I was rear ended by a drunk driver to make a long story short I have had a long recovery and am still going threw treatment, My question:

After the accident and to date I've had neck pain and numbness in my little and ring fingers. I had very severe pain in my neck so bad that just riding in a car was like having no shocks, feeling jolts to my neck even gravel seamed like boulders, and I would get pains in my collar bone as if it was broken.

I went in and had Ulnar nerve surgery to help the numbness in my arm and fingers and in this area has helped, the perplexing thing is as I awoke in the recovery room I noticed a great improvement in my neck pain? and the pain in my collar bone has not returned, this is all on my left side.

I have been told that the Ulnar nerve should not effect the neck in this way, but, I know the relief I have gotten to the neck area since!

I still have damage at the C6,7, and T1 nerve areas. that I am going threw injections for at present but since the operation have been able to drive fairly well though turning of my neck becomes more painful the longer I do.

A friend of mine who has some knowledge in this area has suggested a "double pinch" of the ulnar nerve that she had heard of?
But I've been unable to find any information in this area of question.

Are there any answers? There must be? Is there any information I can be directed to?

I thank you sincerely for any help in this area.

Answer

The Double-Crush syndrome is well known and has been described by Upton and McComas in their landmark paper in 1973

TITLE: The double crush in nerve entrapment syndromes.
AUTHORS: Upton AR, McComas AJ
SOURCE: Lancet. 1973 Aug 18;2(7825):359-62

The basic premise is that when a nerve is injured proximally (or in this case close to the neck), it makes it more susceptible to injury distally (away from the neck).

What exactly happens to give pins and needles sensation?         Top

Question

When you experience the sensation of "pins and needles" what exactly is taking place? Is it a result of the healing process of the nerve or is it a result of damage to the nerve. I know when your foot is "asleep", the pins and needles come after the numbness but before normalcy, as your foot recovers......so I am wondering if the sensation might indicate a reactivation of proper nerve impulses? I'm experiencing pins and needles in association with lyme disease and am wondering if this could be the reawakening of my damaged nerves and thus a good thing.....or does it result as my nerves are damaged, and thus a bad thing? Thanks. Ruth.

Answer

This is quite interesting question. Any or all of the sensory symptoms (pins and needles) and signs are considered diagnostic for a dysfunctional sensory nervous system or point that some thing going on with sensory nervous system. It could either occur at start or later in the process of nerve affection. Although pins and needles may get less with recovery. But does not basically or necessarily be a bad sign.

I have Left elbow pain. Is it necessary to have EMG?       Top

Question

Do I really need this test? I have been treating what the doc thought was tennis elbow. But the cortisone shot I had didn't help that much. So he wants an EMG. I don't want it if it is not necessary! I have always had left neck and upper arm pain (I have Fibromyalgia and injuries from years ago) The main pain is in the elbow area and runs down the arm...It is different form my usual pain. Hurts to use the arm and hand...gripping and pulling mainly! Any advice out there? Sometimes the hand gets cold and tingles and turns bluish too. I still think it is a joint problem.

Answer

You are right. It sounds like a joint problem. However, only tingling suggests nerve problem. Therefore, EMG may be of help.

Comment

Thanks for the quick response. I am concerned that with the Fibro pain I already have that the test will make my pain worse so if I don't need it I don't want it. The arm is also sensitive to touch. Like skin surface pain...all this seems to lesson when I don't use it. That tells me it is a joint problem but the doc said since the marcaine took the pain away for 3 hours it could be nerve pain??????????? Any input here? It is set up for next Tuesday in the doctor’s office. (A neurologist) Wouldn't the marcaine take any pain away????????

Answer

Marcaine should work as local or regional anesthesia and analgesia for pain of any kind, as you said. However, The EMG study should not worsen your pain, although it does cause little pain by itself, which is quite tolerable. EMG is a diagnostic test only.

Brachial plexus injury & EMG          Top

Question

My fiancée was involved a snow mobile accident in January of this year. He sustained 9 fractured ribs, a fractured scapula, a bruised lung, weakness in one leg and brachial plexus injury - all to his right side. It has been 3 months since his accident and he has not gained any movement or sensation of touch in the right arm. He continues to experience severe nerve pain despite taking 50mg nortriptyline and 3000mg neurontin daily (pain management consult). His first EMG is scheduled for next week and subsequent consult with the neurosurgeon. His initial MRI indicated that root avulsion was not "suspected". Is the EMG test definitive for his type of injury? Will this test tell us if he is likely to gain the use of his arm or not? If there is no sign of peripheral nerve activity - what is the next step? Is there any advantage to repeating the EMG at a future date - the first test being a baseline? At what point is an operative option contemplated and what would they be?

Thank you in advance for your time,

Answer

The answers your questions are as follows: EMG/NCS is very useful in suspected cases of root avulsion. But clinical electrophysiological correlation is needed. I mean the examiner cannot interpret its findings alone but should utilize the clinical findings with EMG results. EMG would also help to determine its severity as well as the prognosis. Also, follow up EMG is useful to see signs of recovery after nerve injury. Another test; somatosensory evoked potential is also useful in such cases. Regarding the surgery, it is up to the neurosurgeon. The neurosurgeon would assess the case and decide accordingly.

Ulnar nerve entrapment       Top

Question

One month ago I had an EMG on my left arm. The results indicated an ulnar nerve entrapment, and recommended elbow surgery. I had
continual pain in my arm and hand before the EMG. The pain greatly increased immediately after the test, and has persisted continuously to date. I understand this is not normal. What could be the cause? Has anyone had a similar experience?

Answer

The nerve stimulation itself does not cause any lasting damage and usually the pain and discomfort resolve within 24 hours. In some instances however, nerve irritation during the test can cause an inflammation around it, especially if the nerve is already irritated because of the damage to it. In those instances, anti-inflammatory such as Aspirin or Motrin might help by reducing the inflammation. If they don't something else is going in and it is best to seek a consultation for that.

Comment from another patient

I would suggest caution on this one. I had numbness/tingling symptoms and a specialist (with good recommendations) diagnosed Ulnar Nerve problems. I had a release & transposition on one elbow and a year or so later on the second. It turns out that more than likely the source of the problem was c4-5-6 problems, not the nerve. I did have an EMG to rule out the neck but my guess is the results were inconclusive or false. This syndrome (from my research) is not that common. Feel free to mail me for more specifics

EMG in CTS and double crush syndrome     Top

Question

Hi, I have had an EMG results show carpal tunnel. I also have cervical radiculopathy from disc bulge and spurs impinging on nerve at C5-6 and C6-7.My neurologist does not believe in the "double crush" theory and states that even if he did, I did not have impingement of the C7 nerve. He obviously did not even look at my MRI report, which clearly states this. He also said that because he tested my median nerve at the wrist and it showed compression this proved only Ct. This is not my understanding of the process. My question is; if it were indeed double crush would the testing of the wrist median nerve still show entrapment? Thank you very much

Answer 1

I would say that neurologists are evenly split on the existence (or lack thereof) of the double-crush syndrome. Let me quickly explain it. The double-crush theory says that if your nerve is compromised proximally (up high near the neck) it is more likely than not to be also damaged distally (below near the hand), meaning that the existence of a proximal lesion makes the nerve more susceptible to damage distally. So in answer to your question, if you are a double-crush believer, the testing of the median nerve at the wrist will show entrapment.

Answer 2

The concept of double crush syndrome is known for many years. I think from seventies. It means, there are 2 lesions along one nerve course, i.e. patients with one peripheral nerve lesion did in fact have a second lesion elsewhere and they implied that both lesions were contributing to the symptoms or on another way, somewhat include symptoms which result from a combination of two separate, local lesions at different anatomical sites in the same nerve, whether or not one actually contributes to the causation of the other. Practically, a patient may have carpal tunnel syndrome (distal) and another lesion (proximal) of plexus/root in addition. So, yes, EMG could show a carpal tunnel syndrome (to answer your question), which is fairly easy to diagnose by such method.

Reflex Sympathetic Dystrophy (RSD) and EMG       Top

Question

My husband has RSD (Reflex Sympathetic Dystrophy) and just started seeing a new Doctor. This Doctor is ordering EMG and We're not sure if he should get this test, as you are never supposed to inject anything into the injured area. This year we didn't even get his Flu Shot, as no one really knows if it will hurt him or make the RSD Spread. When someone has RSD you need to watch what you put into you body. Please get back to me soon as he goes for this test tomorrow.

Answer

In general EMG is not contraindicated in RSD. Although it does not test sympathetic nerves, but it is used to exclude nerve injury. Actually, it is one of the tests in work up in patients with RSD.

Pinched Nerve @ C6 when to operate        Top

Question

After FINALLY getting confirmation that I do have a pinched nerve at C6 (EMG) I'v had steroid injection directly into C6. I’ve experience some relief, but it continues to flare up.

My question: is the next step surgery? And what could that surgery be for this specific location?

Answer

It has to be clear that operation or no operation is a surgical decision. However, the surgeons usually try conservative therapy with medications, if no help and pain is severe with abnormal rediology and usually EMG, then the approach is called anterior approach; anterior cervical microdiskectomy.

Can EMG localize if injury level if it is in the spinal cord or not?  Top

Question

Can EMG show if a nerve injury is from the spinal cord?
I took a fall at home in January. Hurt my neck up high. Slowly, I got weakness in arms with uncoordination, then in the legs, with fasciculations, weakness and heaviness.
I was told after EMG that I had nerve damage in arms and legs, particularly in left hand? Can EMG tell exactly where the nerve damage comes from? Since MRI showed bulging at c34, c45, c56 - and hernia at L4-5, it is assumed that my symptoms are related to the disks. However, I just need to know how sensitive the EMG is and what can it actually rule out?

Answer

There are 2 kinds of nervous system; central nervous system (CNS) and peripheral nervous system (PNS). The CNS consists of brain and spinal cord. EMG has no role in diseases or lesions of CNS. But EMG has important role in diseases of PNS, starting from motor neuron at spinal cord down to roots, spinal nerves, plexuses, peripheral nerves, neuromuscular junction and muscles. In spinal cord lesion, if there is associated root (nerve) lesion or damage, then EMG is useful to localize the involved nerve or "level". However, only at C5 and below. Higher level, EMG does not help.

Comment

What symptoms would c34 and c45 bulging cause if these are two areas that could not be detectable on EMG?

Answer

Level C3-4 (C3 root is intact): muscles are flaccid then spastic (after spinal shock). Breathing is affected (patient cannot breathe on his own). Loss of sensation below the neck. Reflexes are brisk (absent initially with spinal shock).
Level C4-5 (C4 root is still intact): Muscles are paralyzed as above. But patient can breathe on his own but low reserve. Sensations are preserved to upper chest but still not in upper limbs. Reflexes changes as above.

I think I need to explain how the C3 root intact at Level C3-4. This can be explained because of anatomy of the roots to vertebral column. At the cervical level, the root exit ABOVE its corresponding vertebra. That is, C3 root pass above the C3 vertebra. Therefore, in C3-4 level, the C3 root is intact and likewise the C4 root is intact at C4-5 level. This rule is only applied for cervical spine but not for thoracic or lumbosacral spine, as the root passes BELOW its corresponding vertebra.

Weird Symptoms       Top

Question

I have been having some strange symptoms for the past 4 years. In 1998, I was tested for possible MS and passed the MRI and nerve reflex tests. My symptoms are intermittent tingling in hands and feet, pain on left arm like a sunburn, weakness in legs, sometimes twist sentences around, vision looks pixeled when looking at solid colors (white and blue the worst), easily go into a stare (daze). Memory really poor. Repeating patterns such as mini-blinds, striped shirts, louvers cause me to see shimmering/dancing patterns. Intermittent shake to the hands, some days there's none at all. At night, the tingling seems to go away. Some days are much worse than others. I also suffer from Migraine headaches about once a week since 1990.

Just want your thoughts what I should do, if anything? Possibilities what it could be? Thanks.

Answer

Migraine can explain some of your visual symptoms, but it may not explain all of them. I think you need another good neurological examination. EMG may also help to rule out peripheral neuropathy, as you have some symptoms suggesting it (tingling and weakness in legs). Some blood tests would also be useful such as B12 level. All the best.

Doctors say I have spinal cord sprain and I cannot understand that term.         Top

Question

I had an EMG, which showed radiculopathy in c spine and Lumbar spine. I have been getting weakness in arms and legs, tingling and small muscle jumps. Doctors did MRI of neck and found bulges. After symptoms progressed, Doctor said I might have spinal cord sprain. I’m trying to look it up and I can’t find any such thing on the internet. He said his physical exam indicated this. IE: hyper tendon reflex. Ever hear of this. Is this a cervical spine sprain? or something different?

Answer

Well I suspect he may have said spinal stenosis (? or spondylosis) causing the increase in your tendon reflexes and the radiculopathies.

Comment

No, he did not specify stenosis, and it didn’t appear on the MRI as a stenosis. And it seemed that the only leg that had hyper tendon reflex was my left leg. (Because I remember him noting that.) What do you make of this? Also, he seemed to get a lack of reflex at my left wrist. Is that a positive or negative sign?

Answer

Spinal cord sprain is not a diagnosis or a clinical condition. Probably a description of something different that your doctor tried to put in layman's term.

Do not know what to make of your "hypereflexia" on one side, this would be certainly the case when you have a stroke, but in problems originating from the back or the neck and involving roots, the case is hyporeflexia on the other side. The same is true for your left wrist.

EMG for Elbow and failed Carpal Tunnel     Top

Question

Please explain which areas of the limb are tested for these problems, I need to be prepared.

Answer

Presumably by failed Carpal Tunnel, you mean a failed Carpal Tunnel release (surgery). The carpal tunnel is located at the wrist, so if your doctor is planning an EMG for the elbow area, he must be looking into other causes for your pain/numbness. Typically an EMG for any arm/neck problems would involve shocks (nerve conduction studies) in the lower half of your arm, and needle examination (no shocks, but a "microphone" type needle to "listen" to electrical activity present in muscles) of the arm and possibly neck muscles. Discomfort felt during an EMG is quite dependant on the individual. Each exam is different for each patient. Skill of the technician or physician administering the test can also have a great deal to do with the degree of discomfort.

When to operate for radial nerve damage? Top

Question

Hello, I’m wondering if you can give me any insight to the EMG results I got today. I fractured my mid humerus 7 weeks ago. It was a closed fracture, but at high velocity. Radial nerve damage was apparent with severe wrist drop and some sensory loss in my hand and forearm. Sensory seems to be recovering slowly but no sign of motor recovery yet. The EMG showed fibrillations at rest and no MUPs. I know that there are differing opinions on when surgical intervention is necessary, but in your opinion, are these results a good indication for surgical exploration? 

Answer

This is surgical decision. The surgeon takes the EMG results into consideration. He may wait for sometime, perhaps several months, to see whether the patient would recover spontaneously or not. But it's his decision at the end of the day.