Pelvic floor muscle exercises with or without electric stimulation and post-prostectomy urinary incontinence : a systematic review

Introduction: Urinary incontinence (UI) after prostatectomy is dif icult to treat and causes profound adverse impacts on the individual’s quality of life. The main clinical treatments available for post-prostatectomy UI consist of behavioral techniques and physical therapy techniques, such as exercises, electrical stimulation and biofeedback for pelvic loor muscles (PFMs). Objective: To investigate the effectiveness of PFM exercises with or without electrical stimulation for reducing post-prostatectomy UI. Methods: We included only randomized controlled trials (RCTs) which used PFM exercises with or without electrical stimulation. The search was conducted in August of 2013 in the databases of the U.S. National Library of Medicine (MEDLINE), Scienti ic Electronic Library Online (SciELO), Physiotherapy Evidence Database (PEDro) and Virtual Health Library (VHL). We searched for RCTs published between 1999 and 2013. As keywords for our search, we used the following descriptors from the Health Sciences Descriptors (DeCS): urinary incontinence, pelvic *Z: Doctoral Student, e-mail: patriciazaidan@gmail.com EBS: PhD, e-mail: elirezsilva@cosmevelho.com.br


Introduction
In Brazil, prostate cancer is the second most common cancer among men (the most common being non-melanoma skin cancer).In absolute numbers, it is the sixth most common in the world and the most prevalent among men, representing about 10% of all cancers.Its incidence is approximately six times greater in developed countries when compared to developing countries.The increase in incidence rates in Brazil may be partially explained by evolution of diagnostic methods (examinations), improvement in the country's information systems, and an increase in life expectancy.The estimated number of new cases in 2014 was 68.000, and the number of deaths up to 2011 was 13.129 (1).
Radical prostatectomy is a signi icant surgical procedure and the most effective treatment for prostate cancer (2).However, this surgery presents several consequences, among which urinary incontinence (UI) is the most distressing (3).As radical prostatectomies have become more frequent as a means of treating prostate cancer, more men have presented with UI.In general terms, it emerges due to an intrinsic weakness of the sphincters, a possible complication which patients must be aware of.The International Continence Society de ines UI as a condition in which involuntary urine loss occurs (4).
The post prostatectomy UI is a complication of dif icult treatment that causes a profound negative impact on quality of life of the individual.In the treatment of benign disease, this complication occurs in less than 1% of cases, while in radical prostatectomy, the incidence ranges from 2% to 87% (5).
There are several UI treatment options, such as pelvic loor rehabilitation, pharmacological treatments, transurethral injections and arti icial urinary sphincters (6).Clinical options for treatment of UI are becoming better known due to their results in reducing UI, as well as the low incidence of side effects and cost reduction.The main clinical treatments for UI consist of behavioral techniques and physical therapy techniques, such as PFM exercises, pelvic loor electric stimulation and biofeedback (7).
Pelvic loor muscle exercises promote increased urethral resistance and urinary control.The objective is to increase awareness of the existence and function of the pelvic loor (8).Functional electric stimulation of the pelvic loor has been described as a conservative treatment available for UI after radical prostatectomy.It arti icially stimulates the pudendal nerve and its rami ications to provoke direct responses and re lexes of the urethral and periurethral striated muscles (9).Electric stimulation is used to passively contract pelvic loor muscles, increasing the awareness of this muscle's contraction for patients who have dif iculty sensing that contractions (10).Physical therapy techniques such as PFM exercises, pelvic loor electric stimulation and biofeedback are therapies which treat this disorder by improving the muscle and nerve components of the support mechanisms of the pelvic organs (11).
This systematic review aimed at verifying the effectiveness of PFM exercises with or without electric stimulation for reducing UI after prostatectomy.

Methods
This systematic review was written according to PRISMA Statement recommendations, duly registered in the PROSPERO, International Prospective Register of Systematic Reviews, number CRD42013006171, accessible at: http://www.crd.york.ac.uk/PROSPERO/

Inclusion criteria
In this systematic review, we included only randomized control trials (RCTs), published in Portuguese or English, which used PFM exercises with or without electric stimulation treatment to investigate the reduction of UI in men after prostatectomy.

Exclusion criteria
We excluded RCTs written in languages other than Portuguese and English; with treatment techniques other than PFM exercises with or without electric stimulation to investigate the reduction of UI in men after prostatectomy; which conducted pre-surgical exercises; and whose sample consisted of patients who underwent transurethral resection of the prostate before radical prostatectomy surgery.

Search strategy
The search was conducted in August of 2013 in the databases of the U.S. National Library of Medicine (MEDLINE), Scientific Electronic Library Online (SciELO), Physiotherapy Evidence Database (PEDro) and Virtual Health Library (VHL).We searched for RCTs published between 1999 and 2013.As keywords for our search, we used the following descriptors from the Health Sciences Descriptors (DeCS): urinary incontinence, pelvic diaphragm, prostatectomy, pelvic floor exercises, electrostimulation and electrical stimulation.We also used the following descriptors from the Medical Subject Headings (MeSH): electrical stimulation, pelvic floor, urinary incontinence, prostatectomy, physiotherapy and exercise therapy.These keywords were combined using AND and OR logic operators.

Selection criteria
The PEDro scale was used for selection, and only studies which obtained a minimum score of 5.0 were chosen, this being one of the most frequent scores of the RCTs with the studied methodological quality (12).Studies were evaluated by the PEDro database.

Results
Below, we present a lowchart of RCT recovery and the selection and exclusion process (Figure 1).The results of studies which used PFM exercises are shown in

Discussion
There are a reasonable number of studies in the literature with strong evidence regarding the effects of PFM exercises with or without electric stimulation on UI after radical prostatectomy.However, this number is considerably reduced upon gathering studies with homogeneous methodologies regarding patients, interventions, comparison, results and study design (PICOS) and/or selecting those of best methodological quality.Our review recovered 33 RCTs, of which only ive met our selection criteria (Figure 1).The European Association of Urology states in its guidelines on urinary incontinence that supervised PFM training is the most recommended conservative, non-invasive treatment for accelerating the recovery of continence after prostate surgery (41).This recommendation is strengthened by the studies of Filocamo et al. ( 2) and Overgard et al. (37), which showed great strength of evidence.2) study used the pad test, but did not present its results or a comparison between groups.Also notable is that the pad test is of Level C recommendation and Level 3 evidence according to the ICS, which suggests that it is a de icient assessment method (44).
Electric stimulation aims at facilitating PFM contractions by promoting their passive contraction (45), thus contributing to strengthening the PFMs and increasing urinary continence.Some authors report that electric stimulation is a method which can augment the success of PFM exercises in patients with UI after radical prostatectomy (46,47,48).However, these results were not displayed by the studies of Moore et al (39) or the Kakihara et al. (40).
Moore et al. ( 39) investigated whether men who received PFM exercises in addition to electric stimulation were able to attain continence faster than those who only received PFM exercises, after 12 weeks of treatment.Fifty-eight patients were randomized into three groups: a control group, a PFM exercise group, and a PFM exercise and associated electric stimulation group.Urinary incontinence was assessed by a 24-hour pad test in the 16th and 24th weeks after the 12-week treatment.Before the intervention, the groups presented, respectively, 385.9 ± 256.9 g, 565.6 ± 403.3 g, and 452. 5 ± 385.1 g of urine loss.Twenty-four weeks after the intervention, they presented 54.1 ± 103.1g, 69.9 ± 113.5g and 98.2 ± 132.1g, respectively.The authors concluded that incontinence was reduced in all three groups, with no signi icant difference among them (P = 0.80).
The Kakihara et al. (40) study investigated the additional improvement of treatment by associating electric stimulation with PFM exercises.The sample comprised 20 patients, of whom10 performed only PFM exercises and the other 10 performed PFM exercises and received associated electrical stimulation.Before the intervention, the groups presented 9.0 ± 8.1 g and 28.0 ± 33.8 g of urine loss, respectively, and after intervention, 3.5 ± 2.4 g and 9.4 ± 12.7 g.The authors concluded that there was no additional improvement by associating electric stimulation with functional training of the pelvic loor (P = 0.47).Nonetheless, both groups presented a signi icant improvement of UI (P = 0.001).
Filocamo et al. ( 2) conducted a randomized trial with 300 men, of whom 150 performed PFM exercises and 160 did not receive any intervention.The authors concluded that there was consistent improvement or complete cure in these patients after one and six months of physical therapy intervention for (respectively) 19% and 94.6% of the intervention group versus 8% and 65% of the control group.This study concluded that pelvic physical therapy after surgery can be considered a good, safe method for treating post-prostatectomy IU and, thus, improving quality of life for these patients (2).
Overgard et al. (37) concluded that after 12 months, urinary continence, measured by the number of disposable guards used per day, was attained by 92% of the group of patients who conducted PFM exercises and 72% of the control group (P = 0.028).The authors report that during the one-year period following surgery, regular, supervised PFM training by a physical therapist specializing in pelvic loor rehabilitation signi icantly reduced UI when compared to those patients who trained on their own.However, this study presented an inconsistency in its urinary continence results, when measuring the 24h pad test after 12 months: The average urine loss of the PFM exercise group was 2 (0 -55) gand of the control group,1(0 -14)g (P = 0.95).
Contradicting the recommendations of the European Association of Urology, Dubbelman et al. (38) concluded that a PFM exercise program is lengthy and costly and, therefore, intensive orientation by a physical therapist is not necessary.However, the authors stated that they were not able to recruit the planned sample size, and thus, the results should be viewed with caution as there is a good chance they have not found where the true difference could exist (type II error).This systematic review found that three of the analyzed studies presented very distinct protocols, some lacking in information about the technique used, thus making it dif icult to evaluate the effectiveness of the intervention.Only the Overgard et al. (37) study presented a complete description of the applied intervention protocol, conducted once a week.This frequency can justify the increase in urinary continence observed after only 12 months of PFM exercises, since exercise programs for the skeletal striated muscles are more effective when conducted two or more times a week (42,43).It is interesting to observe that two of the studies summarized in Figure 1  studies presented some methodological weaknesses that may have compromised their internal validity.

Financial support
The author of this study received a scienti ic research grant from the National Council for Scienti ic and Technological Development (CNPq) to inancially support this study.
It is important to emphasize some important methodological aspects which may have contributed to the results displayed by Moore et al. (39) and Kakihara et al. (40).These studies presented distinct protocols; however, the same parameter of 50 Hz was used for electrical stimulation.The literature suggests that when treating UI caused by muscular weakness, the most commonly used frequencies are 65 Hz or 70 Hz, which stimulate fast twitch ibers; 50 Hz is most commonly used for proprioception of PFM contractions or when preparing muscles to receive a higher frequency (49,50,51).Urinary continence depends not only on the integrity of the internal sphincter and the passive urethral mechanism, but also on the external urethral sphincter, which depends on the integrity of the fast twitch striated muscle ibers (40,52,53).In addition, the initial values of urine loss (g) in both studies are very different among groups and the standard deviation is too high, sometimes greater than the group average, which demonstrates that the samples may have been too heterogeneous, thus compromising the results of these studies.
In a similar study, different in its use of metaanalysis, Zhu YP et al. (54) concluded that associating electric stimulation with PFM exercises did not increase urinary continence more than PFM exercises in isolation.However, this clinical decision must be analyzed carefully: (a) Only four studies were metaanalyzed, a low number which reduces the statistical power for providing a de initive answer (55); (b) The studies presented weak methodological qualitythree of the four studies included in the meta-analysis scored less than ive on the PEDro scale; (c) The Moore et al. (39) and Wille et al. (31) studies used anal surface electrodes for stimulation, which may have contributed to the ineffectiveness of electrical stimulation, as skin resistance is too high and patients feel extreme pain before the pelvic loor muscle contraction ( 56) and (d) All the patients in the Yamanishi et al. ( 24) study performed pre-surgery PFM exercises.

Conclusion
Pelvic loor muscle exercises can be effective for treating urinary incontinence after radical prostatectomy, especially if begun soon after surgery.Associating PFM exercises with electric stimulation did not show additional bene it.However, the selected

Figure 1 -
Figure 1 -Flowcharts and Overgard et al. (37) -used different pad test values to determine continence, and that neither study followed International Continence Society (ICS) recommendations.The Filocamo et al. ( -Dubbelman et al.

Table 1c -
Studies That Used Pelvic Floor Muscle Exercises (PFME) for Treating Post-Prostatectomy Urinary Incontinence (To be continued)

Table 1d -
Studies That Used Pelvic Floor Muscle Exercises (PFME) for Treating Post-Prostatectomy Urinary Incontinence Pelvic fl oor muscle exercise.UI -Urinary incontinence.PEDro -Physiotherapy Evidence Database.(*)This study selected only the more objective assessments.

Table 2a -
Studies Which Used Pelvic Floor Muscle Exercises (PFME) and Electric stimulation for Treating Post-Prostatectomy Urinary Incontinence

Table 2b -
Studies Which Used Pelvic Floor Muscle Exercises (PFME) and Electric stimulation for Treating Post-Prostatectomy Urinary Incontinence