EMG testing
 

Question regarding EMG's to test for nerve damage or entrapment:
Are they painful, and can they cause flares or spread?

Hi swim,
When my neurologist did one on me it felt like a needle sticking me. I didn't feel great pain from the electricity being used but slight pain of being stuck. Very doable in my case. You might experience something different. I didn't have flare ups, spread or triggers but I've read those who have.
The test was needed to measure nerve pain responses and what nerves did and didn't do and which ones were affected. The test was performed on my left arm so that might be a difference.
Since then I've had full body spread but not being related to the EMG.
The test is needed so do it.
Best of luck...

It also depends on who is doing the testing.

I've had four (or maybe 5?) during my lifetime. Two prior to developing CRPS, and two (or three) after.

The only truly bad experience was the last and it was several years into the disorder. My doc had advised against it,since it is considered invasive for CRPS patients, but a WC doc had ordered it, so I felt I didn't have much choice. The technician didn't attempt to finish because she felt it was cruel. I was silently crying, but she could tell I was in agony. I was unsafe to drive after for a few hours. I immediately applied one or two Lidoderm patches and took additional pain meds.

If there is a real chance of it being a different nerve issue, it's probably worth trying. I have to say though, a risk I'd be willing to take for myself--causing potential spread or an exacerbation of symptoms, I wouldn't have considered for my son.

I would encourage you to find a CRPS specialist. A doc whose entire practice is devoted to CRPS patients or someone that comes highly recommended a CRPS support group.

I had an EMG done on my leg a few months ago by my neurologist who said he had lots of experience with them. In my case, it turned out to be excruciatingly painful. I nearly told him to stop a few times, and afterward my leg was much more painful for a couple of weeks until the nerves calmed down. Since the results didn’t tell me anything that I didn’t already suspect, I regret having it done at all.

I asked the neurology office if EMG can cause issues for CRPS patients, and she said they would likely use the electrode adhesive pads instead of needles. So I wonder, does that give equally accurate information?

Hey swim,
Yes. The pads are used instead of needles to lessen a trigger. Just as reliable.
Good luck...:grouphug:

Sticky pads are used for Nerve Conduction Study, they are not painful and are accurate. They do EMG if motor signal is impaired enough on NCS to warrant it. Keep in mind either EMG or NCS will mostly read for larger nerves. Small nerves with damage cannot be read as accurately or sometimes at all. Tests will give a good indication if large nerves are intact but there can still be a problem with smaller ones that doesn't show.

"There are two kinds of EMG: surface EMG and intramuscular EMG. Surface EMG assesses muscle function by recording muscle activity from the surface above the muscle on the skin. Surface electrodes are able to provide only a limited assessment of the muscle activity. Surface EMG can be recorded by a pair of electrodes or by a more complex array of multiple electrodes. More than one electrode is needed because EMG recordings display the potential difference (voltage difference) between two separate electrodes. Limitations of this approach are the fact that surface electrode recordings are restricted to superficial muscles, are influenced by the depth of the subcutaneous tissue at the site of the recording which can be highly variable depending of the weight of a patient, and cannot reliably discriminate between the discharges of adjacent muscles."

http://en.wikipedia.org/wiki/Electromyography

His foot eversion (turning outward) is painful and distinctly weaker than his good foot. I think, from my research, that this points towards a superficial peroneal nerve entrapment. Both EMG and NCS are scheduled. Hopefully, if there is an entrapment, it will show up on testing. Neurology may be able to move up his appointment for testing sooner than mid-July. (Crossing my fingers, and should hear something tomorrow.)

They will get a good read on both superficial and deep peroneal and compare those to the unaffected leg. The superficial branch does drive eversion. Also the cutaneous nerves of the dorsal foot come off the superficial peroneal. It is worth asking if they can read those. They are right there. You can actually see and feel them.

His hardware is on the anterior ankle isn't it?

:hug:

Haha, hardware is pretty much everywhere. :rolleyes: Long plate along the lateral ankle, two huge screws through the anterior ankle in the tibia, another angled screw through the fibula that comes out the other side of the bone into the achilles tendon area, which they said will probably cause tendonitis later if it doesn't come out.

He was fitted for custom orthotic inserts to correct a significant overpronation that is likely increasing pressure on the top of his foot. That could be another possible cause of weak eversion. I'm hoping that will help him tolerate longer periods of weight bearing.

Pain has always been in the band across the top of the foot, the inferior extensor retinaculum. It used to also shoot along the entire top of the foot, stopping short of the toes. Weight bearing and eversion both trigger pain in the band. He's so much better than he was, just very limited still in how much he can do. I'm thankful he's improving, it's just such a long process. The fact that the pain is so localized is what made his doctor suspect an entrapment.