EMG Procedure

[TracyB7777]

The purpose is to see how your pudendal nerve reacts, I believe. At least that's the way it was described to me. Truly once I was home and started to relax it got better. Today is just a normal pain day so the good news I guess is it didn't cause a flare for me. Truly sorry if it was TMI.

Tracy

[Violet M]

This link gives a good explanation of the purpose of the EMG:

http://www.neurohaven.com/emg1.htm

Here is a portion of it:


Making Sense of EMG Studies

Many technicaI factors can affect the test
Juan L. Joy, M.D.

Introduction

Clinical electromyography (EMG) consists of nerve conduction studies (NCS) and needle electromyography (needle EMG). In the strict sense of the word, EMG only refers to the needle electrode examination of muscles, however is has traditionally been used to refer to both NCS and needle EMG. EMC is a very powerful diagnostic modality for the evaluating the peripheral nervous system which, in competent hands, can provide invaluable information that may not be obtainable with any other diagnostic test. It can also complement the information obtained from other sources, such as imaging studies, for optimal localization of a lesion.

More so than most electrodiagnostic tests, EMG is extremely dependent on the skill of the examiner. There are many technical factors which can affect the test and produce erroneous results if not recognized5,6,8. It is also important to note that EMC is not a standard test like electrocardiography. There are dozens of muscles and nerves that can be tested, and it is the electromyographer's job to tailor the examination to the patient's particular clinical problem. What is tested is as important as how competently it is done.

How does it work?

Peripheral nerves transmit electrical impulses and can be simplistically thought of as extremely efficient conductive wires. For NCS studies, a noninvasive stimulator applies brief electrical impulses to a peripheral nerve transcutaneously, the nerve then transmits the impulse and a response is recorded by electrodes at some distance away. The time it takes for the stimulus to reach the recording electrodes (latency) can be accurately measured and a velocity of transmission calculated. Both motor and sensory nerves can be examined. Healthy nerves will transmit the electrical impulse faster than diseased ones.

Needle EMG does not introduce any electrical stimulation, instead it records the intrinsic electrical activity of skeletal muscle fibers. The needle is quite slim (about a 25 gauge) and produces minor discomfort which most patients can tolerate. Needle EMG findings suggestive of denervation include:

fibrillations,
positive sharp waves, and
giant motor unit potentials (MUP).
Abnormalities pointing to a myopathy include small short-duration MUP. Since the root and peripheral nerve supply to the muscles is known, needle EMG can be used to localize peripheral nerve or root lesions by noting which muscles show denervation changes.

For most conditions, NCS and needle EMG complement each other and are performed at the same session.

[helenlegs 11]

Thanks Violet, interesting.
Quote EMC is a very powerful diagnostic modality for the evaluating the peripheral nervous system which, in competent hands, can provide invaluable information that may not be obtainable with any other diagnostic test. It can also complement the information obtained from other sources, such as imaging studies, for optimal localization of a lesion. Unquote

So it could be used to find the site of entrapment possibly. Say if imaging shows numerous abnormalities or potential areas of entrapment that could entail separate surgical procedures, the ENG test could confirm the most symptomatic site.

[DonnaOntario]

Tracy thank you for your reply. I admire your courage as well as telling it 'like it is'. Okay, I admit, I'm scared out of my tree now, I had no idea what it endured. To answer PS, Dr. Gordon is doing the EMG. One more questions Tracy, I am going alone to have the test done, I know how much pain I'm in now, should I possibly bring a driver with me, just in case? Sometimes even driving, moving my foot from one pedal to the other can be painful after tests etc.
I cannot say it enough, how helpful everyone has been on this site. Almost feels like family!

[Pelvis Stressly]

Thanks for the info Donna (just e-mailed Gordon to see about having one done myself...even after Tracy's description!).

Any idea how long he's been doing these? (again, this must be a relatively new acquisition for them, as they never had the technology to do this before) Only reason I ask is, Violet's link (thanks V!) seems to stress the importance of a skilled examiner. Just wondering roughly how many tests Gordon's conducted at this point...

[DonnaOntario]

Oh boy, I hope that I'm not the guinea pig on this one! LOL
I have a call into the office to the nurse Leah. If I don't get any answers prior to my appointment I will be sure to post on here my experience. I will try to remember to ask how long they have been doing these at Mt. Sinai. When I met with Dr. Gordon he didn't give any indication that this was new to their facility. Wish me luck, I'm scared silly!

[Pelvis Stressly]

Well, I think the 'skilled examiner' bit referred more to the accuracy of the findings, not so much the potential for any risks or complications during the procedure! Sure you'll be fine
Good luck, PS.

[TracyB7777]

Honestly if you are already in a lot of pain and have problems driving I would suggests a driver just in case. I made the 40 minute trip home but I know my reflexes weren't what they really should have been. I truly didn't mean to scare you, just thought I'd explain mine while it was still fresh. ICK!!!

[DonnaOntario]

Thats okay Tracy. I just wanted to be prepared thats all. I'm glad to know what I'm up against. Its an over 1 hour drive to the appointment, so I think it best I find a driver too, especially if I hit rush hour! Will give you my comments and experience when I get home. Thanks again for your information, it has been very helpful.

[Violet M]

So it could be used to find the site of entrapment possibly. Say if imaging shows numerous abnormalities or potential areas of entrapment that could entail separate surgical procedures, the ENG test could confirm the most symptomatic site.

Dr. de Bisschop, whose father is a neurologist believes he can locate the area of entrapment with the electrophysiological testing but he's the only doc I know of who claims to be able to do that. Funny thing was before my surgery de Bisschop and Bautrant were not in agreement on where the entrapments were but as it turned out during surgery I was entrapped in every one of the places that either of them predicted I would be. Maybe just lucky guesses, right? We really don't know of any test yet that is proven to be 100% accurate all of the time for locating entrapments.