Pelvic floor EMG (synonym: pelvic floor electromyography) is a diagnostic procedure used in urology and proctology to detect micturition disorders caused by nerves or muscle disorders.Micturition describes the process of urination. With the help of electromyography, it is possible to quantify and subsequently assess the electrical impulses of the pelvic floor muscles. As a rule, pelvic floor EMG is used as an additional procedure in uroflowmetry (collection of different procedures to assess a patient’s micturition). With the help of pelvic floor EMG, it is possible to perform simultaneous recording and assessment of muscle action potentials (electrical currents triggered by muscle activity) of both the striated pelvic floor muscles and the sphincter muscles of the urinary bladder during micturition by electromyogram (EMG). In addition to conventional detection of neurologic or muscular dysfunction in the pelvic floor area, the procedure can be used for therapeutic biofeedback training by additional equipment with acoustic amplifier or a video screen.
Indications (areas of application)
- Micturition disorders – performing a pelvic floor EMG is important in the evaluation of micturition disorders. Unlike other procedures, it is not necessary to use contrast material to visualize the urinary tract, so the risk of complications is very low.
- Stress incontinence (formerly: stress incontinence) – especially in women, stress incontinence is an important mainly psychological problem. With the help of needle EMG, both a qualitative and quantitative assessment of micturition is possible, so the procedure can be used in the causal research in stress incontinence.
- Anal incontinence – outside urology, the procedure is used in the assessment of anal dysfunction.
- Constipation (constipation) – in addition to anal incontinence, the procedure is also used in proctology to diagnose the presence of constipation.
Contraindications
There are no contraindications to performing pelvic floor EMG.
The procedure
For the evaluation of micturition disorders, functional flow EMG is the most important screening examination that should be performed in every child with micturition disorders. However, when evaluating the results, it is important to keep in mind that the urinary flow rate changes according to both age and sex and, therefore, unadjusted comparisons are not possible. For adequate assessment of pelvic floor function, a minimum micturition volume of 150 milliliters should be aimed for. Procedure of pelvic floor EMG
- To achieve optimal assessment of the pelvic floor muscles, care must be taken to ensure precise positioning of the adhesive electrodes for EMG derivation. For conduction, two adhesive electrodes must be positioned in the anus area (in the region of the anus) and another must be positioned on the thigh as an indifference electrode (grounding electrode). For needle pelvic floor EMG, needle electrodes are applied to the tissue instead of the adhesive electrodes.
- The recordings of the EMG are made using a 2-channel recorder. During the micturition phase, the recording of the urinary flow curve and the activity of the pelvic floor muscles can now be measured and subsequently assessed.
Distinguish between different methods of electromyography to assess the pelvic floor.
- Pelvic floor EMG can be used to evaluate the entire striated musculature of the pelvic floor. However, two different methods can be distinguished in pelvic floor EMG.
- It is possible to perform a nonspecific and simple surface EMG as well as an accurate, but very complex pelvic floor EMG using needle electrons. The surface EMG is usually sufficient for the majority of questions.
- However, although needle pelvic floor EMG produces significantly more accurate results, the procedure is used less frequently because it is far more painful than surface EMG. Nevertheless, needle EMG can by no means be dispensed with, since this procedure makes it possible to determine the spontaneous activity of each individual muscle.Based on this, it is possible to perform a so-called “mapping” of neurological dysfunction or even scars in the area of the pelvic floor.
- Despite this precise assessment of tissue structures, it can be seen in clinical studies that the examination results of both methods vary greatly and are further examiner-dependent. This is based in particular on the fact that the procedure requires some experience. As a result, it can be stated that needle EMG in particular is reserved for very specific questions. As a result of the difficult comparability of results, the procedure is not an optimal routine method, but can be outstanding for the individual in the assessment of proctological and urological pathological processes.
- A special feature of the procedure is that with the help of the pelvic floor EMG both an acoustic and graphic assessment of the electrical signals is possible, so that neurological or muscle disorders can be detected more quickly.
Examination findings during a pelvic floor EMG.
Physiological examination findings
- When physiologic urinary bladder function is considered, an increase in motor activity of the pelvic floor muscles can be observed simultaneously with urinary bladder filling. Here, a maximum activity is reached shortly before the onset of micturition.
- Since a relaxation of the sphincter mechanism occurs at the beginning of micturition, a significant reduction in action potentials can be detected in the EMG, which in the optimal case causes a complete silence of activity. Coughing, for example, can significantly increase activity in the electromyogram, so care must be taken in the interpretation of such disturbances.
Pathological examination findings
- Consistent or increased activity during the micturition phase should be considered pathological. The presence of continuous or alternating increases in activity indicates dysfunction of the muscles involved in micturition.
- However, a non-physiological decrease in activity may indicate denervation (lack of supply of electrical control stimuli to the tissues). To be able to confirm the diagnosis, possible artifacts (erroneous measurements) must be excluded beforehand. In addition, the findings must be demonstrated in different potentials.
Possible complications
No complications are expected with surface EMG. Only through the electrodes can skin irritations occur. Needle EMG, on the other hand, is associated with a higher risk of complications, which can nevertheless be considered very low. The use of needle electrodes can cause injury to nerves and blood vessels. Injury to nerves may result in a mostly temporary effect on sensation but is usually not detectable.
