© Borgis - New Medicine 1/2008, s. 3-7
*Krystyna Garstka-Namysł1, Juliusz Huber 2, Alicja Witkowska2, Magdalena Pisarska3, Kamila Witczak3, Łukasz Sroka3, Stefan Sajdak3, Grzegorz H. Bręborowicz4
INDIVIDUALLY PLANNED FUNCTIONAL ETS AND EMG BIOFEEDBACK AND SUPRASPINAL FES STIMULATION OF PELVIC FLOOR MUSCLES IN WOMEN AFTER GYNAECOLOGICAL OPERATIONS WITH SYMPTOMS OF URINARY INCONTINENCY
1Section of Recreational Sports in the Chair of Pedagogy of Leisure and Recreation of the University School of Physical Education in Poznań Head of Section: Dr Krystyna Garstka-Namysł 2Department of Pathophysiology of Motor Organs of the University of Medical Sciences in Poznań 3Chair and Clinic of Perinatology and Gynaecology of the University of Medical Science in Poznań 4Department of Hygiene of the University School of Physical Education in Poznań
Summary
Background: Women with symptoms of urinary incontinence and after gynaecological operations experience pelvic floor muscle and nerve action disorders which significantly affect their functional state. On the basis of the results of global electromyography, parameters for supraspinal stimulation (FES) and transvaginal electrical muscle stimulation (EMS) can be individually specified and the effects of therapy objectively assessed.
Material and methods: In 25 randomly selected (out of 236) women after gynaecological operations (on average 9 months after operations) with symptoms of micturition disorders the following examinations were carried out: gynaecological, urodynamic, ultrasonographic and psychological. In patients without contraindications for electrotherapy, global electromyography using an intravaginal electrode was carried out as well as examination of motor evoked potentials (MEP) induced by a magnetic field. Parameters for EMS and FES were selected individually, on the basis of the diagnostics results of nervous and muscular disorders. Comparative EMG and MEP were carried out after patients had undergone the therapy for two months at home.
Results: on the basis of diagnostic tests in 85% of patients a neurogenic cause of the complaints was found in the form of axonopathy of motor fibres rather than weakening of impulsation at the level of neurons of the motor centre. Muscle resting tone was on average 2.52 ?V before the therapy and 1.87 ?V after therapy. Action potential in the phase of contraction was 11.41 ?V before and 16.92 ?V after therapy.
Conclusions: EMG tests have shown a beneficial, statistically significant increase in the amplitude of muscle tone measured in exercise conditions. A two-monthly therapeutic cycle of electrostimulation resulted in an improvement of the functional state of motor units (stability) in the conditions of maximum contraction and post-exercise relaxation. Our study demonstrates that therapy of muscle activity disorders using the EMS and FES methods preceded by global electromyography and visualisation of contraction using EMG biofeedback has expected therapeutic effects.
Background
In the literature statistical studies show definitely that a gynaecological operation such as hysterectomy causes a basic change in the life of a woman, in particular if it is related to post-operative micturition disorders. In the study of Ralph and Lichtenegger (1988) [1] it was found that compliance of the bladder deteriorates in 69% and incontinence occurs in 31% of patients after radical hysterectomy. In the long-term studies of Sekido, Kawai and Akaza (1997) [2, 3] it was demonstrated that even ten years after hysterectomy, disorders in the urinary passage can be observed, as well as such dysfunctions as constipation, retention of urine, and detrusor hyporeflexia. Other neurological studies of Chang et al. (2003) [4] showed that damage of somatic and autonomic nerves cause micturition disorders in patients after radical hysterectomy. Taking into consideration the fact that hysterectomy is the most frequently performed gynaecological operation in Poland and in the world [5], it is important to develop effective methods of prevention and treatment of micturition disorders caused by hysterectomy, adjusted individually for a patient´s indications. Physiotherapy is considered by many authors an irreplaceable method in the treatment of pelvic floor muscle disorders, including urinary incontinence [6, 7, 8]. Physiotherapy methods include EMG biofeedback exercises and electrotherapy involving electric stimulation of pelvic floor muscles and supraspinal functional stimulation [9, 10, 11].
The use of global electromyography for diagnosis and treatment of muscle activity disorders allows objectivisation of tests [12, 13] and the use of EMG biofeedback methods significantly increases the effects of therapy [14, 15, 16, 17, 18]. Due to various health components leading to the same symptoms in various patients, we decided to establish individually parameters of the NMES and FES electrotherapy and EMG biofeedback exercises, on the basis of the diagnostic test results and tests of Work/Rest muscle activity carried out under the control of non-invasive global electromyography (transdermal).
Material and methods
The study covered 25 women randomly selected from a group of 236 patients after gynaecological operations, on average M=8.6 months after their operations, with symptoms of urinary incontinence. All women from the experimental group were qualified for the study (gynaecological, ultrasonographic, urodynamic, psychological, neurophysical examinations) and their socio-demographic characteristics were established.
Urodynamic test
UD diagnostics on the basis of natural uroflometry with the measurement of residual urine, water cystometry and urethral profilometry was carried out, using the DUET Logic/MultiP (Medtronic) device, according to medical indications. Before the UD test, general urine and urine culture analysis was carried out. All patients with urinary tract infection symptoms were excluded. In women with a history of recurrent urinary tract infections, anti-inflammatory prophylaxis was started before the urodynamic examination.
EMG test
For the EMG test an integrated Key Point Portable system (Medtronic) and the system of global EMG measurement – NeuroTrac(r)ETS (Verity Medical Ltd.) were used. The first EMG measurement was carried out after the operation, directly before beginning therapy (2 months at the earliest, 18 months at the latest, 8.6 months on average) in order to establish neurogenic components of incontinence symptoms and the degree of muscle activity disorder intensity. The second measurement was carried out directly after the therapy. EMG recordings and later electrostimulation were performed using an intra-vaginal electrode Veriprobe (Verity Medical Ltd.) inserted by the patient herself. Patients were carefully prepared and instructed for this.
The first stage of the EMG test using the 2-channel NeuroTrac(r)ETS device involved assessing the pelvic floor muscle resting tone in lying and standing position followed by the standardised muscle activity test Work/Rest Assessment, including five 5-second contraction cycles (Work) followed by five relaxation cycles (Rest). This test allowed us to establish the average value (expressed in microvolts) of muscle activity in the contraction and relaxation stage (mean and standard deviation for each of the stages separately), which describes the stability of muscle tone in the stage of contraction and relaxation, and the average time (expressed in seconds) of reaction to order of contraction and relaxation. After a three-minute rest, each patient carried out exercise tests as a sequence of ordered activities: retraction of the anus, pressure test, laugh test, cough test in the lying and standing position. There was a 30- second rest after each activity. The results of the resting and exercise tests made it possible to establish muscle efficiency, the range of conscious control over their activity and to adjust individually parameters of FES and NMES stimulation.
The second stage of the EMG test performed using the same intra-vaginal electrode on the Key Point device involved carrying out the same sequences of activities as in the first stage and recording potentials from the muscles characteristic for a given activity.
In the third stage motor evoked potentials (MEP) induced by a magnetic field were recorded within motor units of sacral neurosegments of the spinal cord.
Psychological test
A psychological test was carried out using questionnaires on the sense of quality of life according to S. Kowalik and questionnaires in the authors´ own perspective which measured five functional states of life situation of women, including physical, material, social and mental state as well as state of life activity and fitness. Getting to know these spheres of life and ways of their evaluation makes it possible to establish the psychological consequences (changes in evaluation) of a gynaecological operation and of a specially selected therapy.
Therapeutic activities
On the basis of the collected diagnostic data, parameters of neuro-muscular electrical stimulation (NMES) were set as well as parameters of functional supraspinal stimulation (FES). Significant differences in results of exercise and muscle resting tone and disorders of conduction of motor nerves found in the MEP test required the use of varied parameters of simulation, appropriate for the test results. Patients were equipped with a specialist pelvic floor muscle and nerve stimulator, intra-vaginal electrode (Veriprobe) and a set of self-adhesive electrodes 50x100 mm (Verity Medical Ltd.) for the supraspinal stimulation. The Neuro Trac 4-Continence (Verity Medical Ltd.) stimulator allows one to set individual stimulation parameters and record them in the user´s programme. After thorough training on the use of equipment and providing detailed written indications for the performance of treatment, patients continued the therapy at home for 8 weeks, on average for 10 -15 minutes 2 to 3 times a day.
Results
In urodynamic tests in 85% of subjects, neurogenic disorders in bladder emptying were noted in the form of: urine overflow incontinence (N=15), mixed type (N=4), overactive bladder (N=2), and difficulties in beginning micturition (N=4). In the EMG tests the neurogenic component of disorders was noted which resulted from axonopathy of motor fibres rather than weakening of impulsation at the motor centre neuron level. Preliminary EMG examination established the current potential of power in the phase of conscious contraction and resting tone before and after exercise and was a benchmark for the comparisons after the completion of the therapy. The average value of pelvic floor muscle contraction strength, which guarantees continence, varies and is usually in the range 15-60 ?V. Values below <5 ?V were adopted as the norm for relaxation. Values of contraction above>60 ?V and values of relaxation above>5 ?V suggest spasticity of pelvic floor muscles which often coincides with micturition initiation difficulties, retention of urine, detrusor hyporeflexia, detrusor-sphincter dyssynergia, and chronic infections of pelvic floor structures. In Work/Rest and resting tests performed using EMG biofeedback before the therapy, instability and increase of pelvic floor muscle resting tone was noted (on average 2.52 ?V) compared to the records of healthy patients (on average 1.3 ?V) (Figs. 1-3). In comparison of the EMG test before and directly after the completion of the therapy it was shown that individually for each patient selected NMES and FES therapy beneficially affected the amplitude of resting tone, showing a decrease (on average 26%). Moreover, a significant improvement in the functional state of motor units in the conditions of maximum contraction was noted (by 17%) as well as significantly better stability of contraction (improvement in 69%) (Tables 2 and 3). Also, an improvement in conductivity of motor potentials from the motor centre to the muscle was noted, which was confirmed by the MEP test in all studied women.
Fig. 1. Muscle resting tone of various scale of disorders before the therapy (in the scale of 10 microvolts).
Fig. 2. Effect of electrotherapy on the strength of muscle contraction (effect of therapy before [left]] and after [right]).
Fig. 3. The effect of lack of electrotherapy before (left) and after (right).
Table 1. Effect of electrotherapy on muscle activity.
Stage of study | Relaxation beforeexercise in ?V | % changeability indicator for rest | Mean value of strength in the contraction phase in ?V |
Before the therapy | 2.52 | 11.39 | 11.41 |
After the therapy | 1.87 | 7.83 | 16.92 |
% change | +26% | +69% | +48% |
* own study
Table 2. Comparison of indicators of pelvic floor muscle activity for exercise and rest tests.
Muscle activity Test Work/Rest/Assessment | Mean | N | Standard deviation | Standard error of mean |
Mean contraction strength in I P (?V) | 14.517 | 18 | 8.8915 | 2.0957 |
Mean contraction strength in II P (?V) | 17.667 | 18 | 8.3456 | 1.9671 |
% changeability indicator for relaxation in I P | 11.39 | 18 | 4.159 | 0.980 |
% changeability indicator for contraction in II P | 7.828 | 18 | 2.552 | 0.6018 |
* own study
Table 3. Change in pelvic floor muscle activity in exercise and in rest in the group undergoing electrotherapy
Pelvic floor muscle activity | Difference between measurements | Differences in dependent tests Test Work/Rest Assessment | Bilateral significance |
Mean | Standard deviation | Standard error of mean | t | Df | p |
Contraction strength | 1-2 | 3.150 | 5.3398 | 1.2586 | -2.503 | 17 | 0.023 |
% changeability indicator of relaxation strength | 1-2 | 3.5667 | 4.0827 | 0.9623 | 3.706 | 17 | 0.002 |
* own study
Discussion
The rules of individual setting of stimulation parameters for incontinence therapy are poorly addressed in the literature. Many trials describe positive effects of biofeedback and electrostimulation therapy in patients with genuine stress or mixed incontinence using the same parameters for all patients involved. On the basis of EMG and MEP readings carried out by our patients, we are convinced of the necessity of individual parameter setting. Such stimulation parameters as frequency, work and rest time, pulse width, pulse increase time, oververtebral electrodes application for FES, and overall therapy time, should depend on individual need, stated previously in the EMG biofeedback investigation (resting and exercise test) before the therapy. The use of EMG biofeedback to demonstrate muscle condition and show to the patient her volitional influence on muscle action is irreplaceable. It also helps to teach correct pelvic muscle contractions. After some weeks of stimulation (depending on the effects in the individual) one should perform each second/third muscle contraction together with the stimulator. Not only individually set stimulation parameters are responsible for good effects but the involvement of the patient in the whole therapy too. The use of the same stimulation parameters for all patients with the same symptoms but different nerve and muscle condition can cause in some of them overloading of very weak muscles and lead to failure of the whole therapy.
Conclusions
Pelvic floor muscles are responsible for maintaining the organs of the abdominal cavity and organs of the pelvis minor in the correct position. As a result of strengthening the muscles they may better resist intra-abdominal pressure increase during cough, laugh and physical strain, and guarantee continence. Removal of the uterus (with or without adnexa), as a result of hysterectomy, causes disorders in the statics of pelvic organs and damage of pelvic floor muscle motor axons, leading to axonopathy. Electrotherapy directed at strengthening the muscles and improving the function of motor units seems to be particularly important for women undergoing gynaecological operations. Beneficial effects of individually planned electrotherapy according to the principles described in our study may be understood as an improvement of neuro-muscular co-ordination as a result of better nervous conductivity, partial regeneration of damaged axons of motor nerves and strengthening of power of muscles responsible for continence. The data collected in psychological tests (improvement of sexual satisfaction) and on the basis of regularly decreasing intensity of stimulation needed for a contraction (on average 35% less than at the beginning of the therapy) also indicate a significant improvement in terms of conductivity of sensory nerves. To sum up:
1. The EMG tests show a beneficial, statistically significant increase in the amplitude of muscle potential measured in exercise conditions.
2. A two-month electrostimulation treatment cycle also resulted in an improvement of the functional state of motor units in conditions of maximum contraction and post-exercise relaxation.
3. Our study shows that electrotherapy of disorders in muscle activity using the EMS and FES methods, preceded by global electromyography and visualisation of contraction using EMG biofeedback, has the desired therapeutic effects.
4. The effectiveness of electrotherapy of pelvic floor muscles is greater if the parameters of intravaginal muscle electrostimulation (EMS) as well as supraspinal transdermal FES are individually planned.
5. The preliminary diagnosis of disorders using urodynamic tests and global electromyography (EMG) is of basic significance for clinical practice.
Piśmiennictwo
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