Urology & Urogynecology > Education and Reference

PROCEDURAL NOTES

EMG WITH SURFACE (PATCH) ELECTRODES

DEFINITION:
Electromyography (EMG) is the study of the bioelectric potentials generated by depolarization of skeletal muscle.

INDICATION:
Coordination or discoordination of urethral sphincter activity is directly relevant to detrusor activity. This makes it useful in the diagnosis of incontinence, frequency, urgency and voiding dysfunction.

PURPOSE:
To provide documentation relevant to the neurological coordination of urethral striated muscle associated with urodynamic studies (male urethral sphincter or female urethral striated muscle).
Urodynamic Electromyography is always performed in conjunction with other urodynamic studies.

*NOTE:

Optimum EMG information is obtained by inserting wire or needle electrodes directly into the urethral striated muscle. However, should the practitioner elect not to use invasive procedures to obtainthis information, surface patch electrodes are available. The use of surface (patch) electrodes is based on the assumption that an individual's anal sphincter muscle and urethral sphincter will contract and relax in unison, therefore, an intact Bulbo-cavernosal reflex should be confirmed. Skin preparation, adhesion and proper placement are critical when using patch electrodes. Patches that have gotten wet during leakage or voiding may display a signal consistent with muscle activity, therefore, a diagnosis of dyssinergia should only be made with extreme care when using patch electrodes.

INSTRUMENTS & SUPPLIES NEEDED:
>> Life-Tech Urodynamic System with sufficient operating channels and EMG software
>> 2253A-1 EMG for Urolab Spectrum
>> 2153A-1 EMG for Urolab or UroVision
>> Life-Tech 1309 Audio Monitor (recommended option)
>> Life-Tech SA1012 EMG Electrode Cable
>> Life-Tech EC-18TP (3) Surface Electrode Cables
>> Life-Tech H0959 Pre-gelled Surface Electrodes
>> Life-Tech 8507 Gold Ground Plate Electrode (optional)
>> Paper tape
>> Electrode gel (if using 8507)
>> OmniPrep (if using 8507)
>> Alcohol pads
>> Gauze pads

INSTRUMENT PREPARATION:

1. Insert the EC-18TP surface electrode cables into the SA1012 EMG electrode cable. NOTE: The 8507 (reusable) Gold Ground Plate electrode may be used in place of the green surface electrode cable, as the EMG ground.
2. Snap the electrode patches on all cables. The audio monitor should be “off” at this time to eliminate unwantd noise.
3. Select a procedure configuration on the Urodynamic System that contains an EMG channel.

PATIENT INSTRUCTION AND PREPARATION:
1. Explain to the patient that, as part of a complete urodynamic examination, it is necessary to test the activity of the external urethral sphincter. This procedure will involve the placement of two small adhesive patches on the anal sphincter.
2. Place the patient in the lithotomy position, or turn them on their side.
3. Instruct the patient to relax.

NOTE: If a balloon catheter is going to be inserted in the patient’s rectum to measure
abdominal pressure during urodynamic procedure, it can be inserted either before or after
patch placement, according to the users preference. HOWEVER, it is recommended that a
MINIMUM of lubricant be used on the catheter.

PLACEMENT OF ELECTRODE PATCHES
1. With a gloved hand, spread the buttocks until the entire anal sphincter is visualized. Any hair in that might be under the patches when replaced should be removed.
2. Thoroughly clean the anal sphincter area with alcohol. NOTE: It is extremely important that all oil, hair and foreign material be removed from this area before the electrodes are placed.
3. Without releasing the buttocks, dry the area free of any remaining moisture from the alcohol pad.
4. Place the BLACK and RED electrode patches directly ON opposing sides of the sphincter. The patch should actually be placed ON the darker skinned area of the anus.

ATTACHMENT OF THE GROUND ELECTRODE
1. Thoroughly clean the area of the adductor tendon, as close in to the groin as possible, with Omniprep and a gauze pad. Remove all Omniprep residual.
2. Place the GREEN patch electrode on the cleaned area. The GOLD GROUND PLATE ELECTRODE (as illustrated on the previous page) can also be used as the ground/reference lead for surface EMG. To utilize this electrode as the ground:
    - Tear two pieces of 2” paper tape and place them in a convenient location.
    - Prepare the site as described in #1 above.
    - Apply electrode gel to one surface of the ground plate electrode.
    - Position the ground plate close into the groin with electrode gel surface on the patient’s skin, and tape securely.
3. Tape all the electrode wires in place as shown. Be careful to leave enough slack in the wires to avoid pulling on the patches when the patient moves or is seated on the commode. The taping technique is similar for male and female patients.
4. Turn on the EMG Audio Amplifier and ask the patient contract their pelvic floor at the start of the urodynamic procedure. This will help you to verify that you have adequate EMG signal.
5. Adjust the EMG gain (scale) to show a pencil thin line at EMG rest and a moderate signal increase when the patient coughs or contracts their pelvic floor (Kegel).