Urinary Incontinence is a clinical problem that most people deny because of shame and because they consider it is a problem of aging (
6). It has great economical, social, and psychological impact (
10), thus effective measures should be taken to solve it.
Biofeedback is a technique by which a physiological process that is usually unconscious is presented to the patient and to the therapist through a visual or audio signal or a combination of both. This signal is subsequently used to teach and correct the physiological process, achieving a therapeutic effect (
8,
11). Biofeedback is considered as an operant conditioning therapy (
12). It is thus an instrumental technique of PFMT with permanent feedback and in a close chain. This operant conditioning therapy is known as Skinner’s type and it is some what different from the classic Pavlov’s conditioning therapy, in which a stimulus is substituted by another (
13). In USA, BFB is supported by extensive evidence and therefore is accepted as a paid treatment for 3 pathologies, migraine and tensional headache (
14), urinary (
6), and faecal incontinence (
15), as the Harvard Pilgrim Health Care Institute states for its medical policies on biofeedback.
Most studies worldwide have stated that EMG-BFB is an effective technique for the treatment of UI (
5-
7,
16,
17). In the case of manometric-BFB and UI, studies are scarce. Most of manometric-BFB studies have been done on the treatment of faecal incontinence. There subsides the importance of this study.
Manometric-BFB is not recommended for patients with vaginal athresia (colpoathresia), in virgin females and in children (
13); in such cases EMG-BFB is the recommended technique, and therefore is currently the most used BFB technique.
Urinary Incontinence is related to aging and is more common in females (
18), as it was observed in the current study. The most common age was between 41 and 60 years, as already stated by Geanini-Yaguez (
5) and Fernandez-Cuadros (
6). The most common UI type in this study was SUI, followed by UUI and MUI, as stated by Espuna-Pons (
19).
The high prevalence and the economic and social impact on public health allows us to study if as many as 6 sessions of manometric biofeedback protocol are effective enough to improve QoL and manometric values of patients with UI. In times of crisis, it is essential to develop effective and low cost treatments.
To date, there has been controversy on treatment protocols related to frequency, intervals of treatment, and type of muscle exercises (tonic or phasic) used for UI (
6,
7). For example, Hay-Smith suggested that the regimen should consist on 3 sets of 8 to 12 tonic contractions sustained for 8 to 10 seconds each, and performed 3 times a day; these must be continued for 15 to 20 weeks (
20). Munoz -Bono reported that the treatment protocol for faecal incontinence might vary from 1 to 15 sessions, which is due to the difference in learning and comprehension between patients, as stated by Rao (
21,
22). Gilliland goes even further and states that BFB effectiveness seems to be related to the number of sessions (
23). Several authors reported that duration, number, and frequency of sessions are variable. Rao supports 3 to 6 sessions, 60 to 90 minutes in duration, while Suarez-Crespo suggests 4 to 6 sessions of 45 to 60 minutes duration (
24). Fernandez-Cuadros et al. demonstrated that 30 minutes of tonic exercises, 2 times a week for up to 20 sessions is effective for diminishing losses and improving QoL in male and female patients with urinary and faecal incontinence (
6,
25).
With respect to BFB protocols, as already stated by different authors worldwide, there is great variation and controversy on treatment protocols; some investigators state that duration should last 30 to 60 minutes (
26). Grosse supports that at the beginning of BFB, the duration per session should not exceed 10 to 15 minutes, including the resting time, because of fatigue and concentration factors (
14). Guerra-Mora stated that frequency of sessions should be 1 or 2 per week. As the exact number of sessions to get the maximal contraction on pelvic floor muscles is not known, Guerra-Mora observed that after 3 sessions of EMG-BFB, there is no greater improvement on pelvic floor contraction, yet, the maximal force was maintained up to 6 sessions (
26). That is the reason why only 6 sessions of manometric-BFB protocol in the current study demonstrated effectiveness in improving manometric values and QoL.
When it comes to deciding the type of BFB, Suarez-Crespo stated that the ideal method depends on the availability, the expertise, and the experience of the caregivers (
24). In the hospital of the current study, there was years of experience using manometric-BFB, so this technique was applied for the patients with UI. Moreover, Suarez-Crespo suggested that EMG-BFB and manometric-BFB are similar regarding efficiency (
24). However, the effectiveness of different BFB techniques is still under debate. Glia stated that manometric-BFB is superior to EMG-BFB, while Heymenn claimed that there is no significant difference between them (
27). What is clear is that BFB shows good efficacy in short term, measured by QoL scales and by psychological state (
28). However, in the long term, follow-up studies indicate a fading effect over time (
28). Even though, a high percentage of patients (up to 50%) continue to report satisfaction even after 12 to 44 months since treatment (
29).
Biofeedback improves UI, yet, the mechanisms are still unclear (
27). The reason why BFB (an instrumental technique of PFMT) is effective on UI might be because: 1) PFMT activates the perineum-detrusor inhibitory reflex (R3 of Mahony) (
13) acting on UUI episodes (
5,
11); 2) PFMT maintains the correct position and mobility of the urethra, which is fundamental especially for female incontinence (
7); 3) PFMT compresses the urethra against the pubic symphisis increasing intra urethral pressure, thus giving resistance to voluntary voiding of urine (
7), acting on SUI; 4) PFMT protects passive containment elements (ligaments and fibrous elements) and nerve structures from exposure to stretch (
13,
30).
Several studies have demonstrated the effectiveness of EMG-BFB on UI basically on SUI and UUI (Robles and Sari) (
9,
17). Recent studies have demonstrated EMG-BFB utility even on UUI in male and female patients (Geanini-Yagüez and Fernandez-Cuadros) (
2,
5,
6). Unfortunately, there are only a few studies on the effectiveness of manometric-BFB on UI and its subtypes. There subsides the originality and the importance of the study. There is no doubt that manometric BFB is effective on faecal incontinence, as almost 60 studies support it (
25). The present study demonstrated that manometric BFB improves manometric values and UI, measured by I-Qol (as already stated by Sari and Garcia-Bascones) (
9,
31) and ICIQ-SF (as Lorenzo-Gomez and Glazer and Lane previously reported) (
7,
32).
The objective to use validated instruments on UI, such as ICIQ-SF and I-QoL, is to provide evidence for the severity of symptoms before treatment and to evaluate the impact of BFB protocol after treatment (
1). This improvement is clearly observed in our study, and with statistical significance.
Whether manometric-BFB produces improvement on manometric values in the contraction of pelvic floor muscles is still a matter of controversy, and the mechanisms involved are still poorly understood (
9). Guerra-Mora stated that improvement of EMG-BFB values showed no clear correlation, neither with symptoms nor with QoL (
26). Seiman observed that in the BFB treatment, the size of improvement in anorectal pressure gradient or in anal electromyography activity does not seem to be relevant to treatment outcome (
33). Fernandez-Cuadros observed that although the shape of exercises on EMG-BFB protocol got better, the intensity of contraction did not increase significantly after treatment (2.97 mV vs. 2.67 mV); in fact, it already diminished, although not significantly (P = 0.28) (
2). According to Grosse, the reason for this observation is that adipose tissue, cutaneous resistance, vaginal impedance and electrodes positioning are very variable, and the obtained measures have no value between sessions. It would be reliable only if the measures are made on the same session and with the electrodes kept on the same position during the evaluation (
13). Even so, Marrinaci claimed that the improvement on strength of muscle contraction is correlated with BFB measures (
13).
Apart from all the controversy on BFB measures, in this study, the manometric-BFB protocol improved the QoL measured by ICIQ-SF and I-QoL scales/questionnaires, and significantly increased maximal and mean manometric values of pelvic floor muscles (P < 0.001).
The execution of manometric-BFB protocol by the supervision of a physiotherapist and the use of visual and/or auditory signals allowed patients a correct execution of the tonic/phasic exercises protocol. The partnership between patient-physiotherapist: a) increases patient satisfaction and improves compliance and adherence to treatment, b) lets a rapid recognition of pelvic floor muscle exercises (
13), and c) enhances learning and comprehension of exercises, since the number of sessions are dependent on patients motivation and cognitive level (
21,
22).
The 6-session manometric-biofeedback protocol implemented at Santa Cristina’s Hospital improved QoL and reduced UI, as compared with other protocols, which are substantially larger, as the one introduced by Fernandez-Cuadros et al. (20-session protocol) (
5,
6). This finding has direct impact on the health care system, because of the shortness and effectiveness of the protocol, and it could therefore be recommended to other public and private institutions, due to its cost/effectiveness properties.
The UI produces an economic impact derived from direct and indirect costs. The direct cost of UI includes diagnosis (specialist consultation and exams), rehabilitation, pharmacologic and surgical treatment, diapers, washing/cleansing products, and transportation expenses to medical facilities. The indirect cost includes labour absenteeism, productivity impairment, quality of life impairment, and caregiver’s salaries. In the USA, the direct cost per patient (diagnosis and treatment) was 600 dollars. In patients older than 65 years of age, the cost can go up to 3,565 dollars per patient. In Spain, a physiotherapist session is valued 53 euros per day (
8). The reduced protocol will have an impact on the health system (less number of sessions and less use of medical resources) and in the economy of patients (less use of diapers).
One important limitation of this study was the absence of control group due to the small sample size (n = 31). Since PFMT and BFB have proven effects on the improvement of UI, it is not ethical to deny such an intervention for patients with UI. A quasi-experimental before-after study, also known as a non-randomized control trial, was used to solve such an ethical problem. Besides, it was an experimental study with recognised medicine-evidence based level (2B, according to the Canadian task force) (
34).
4.1. Conclusions
Manometric BFB protocol is capable of decreasing UI and improving QoL and manometric values, measured by ICIQ-SF/I-QoL scale/questionnaire and by manometric BFB evaluation. This reduced protocol could be applied to other public and private institutions and it could have an economic impact on the health system and on patients’ economy.