Pelvic floor muscle training and electrical stimulation as rehabilitation after radical prostatectomy: a randomized controlled trial (2024)

Abstract

[Purpose] To investigate the effect of electrical stimulation and pelvic floor muscletraining on muscle strength, urinary incontinence and erectile function in men withprostate cancer treated by radical prostatectomy. [Subjects and Methods] One hundredtwenty-three males were randomized into 3 groups 1 month after RP: (G1, n=40) control;(G2, n=41) guideline: patients were instructed to perform three types of home exercises tostrengthen the pelvic floor and (G3, n=42) electrical stimulation: patients in this groupwere also instructed to perform exercises as group G2, and also received analelectro-stimulation therapy, twice a week for 7 weeks. The primary outcome assessment wasbased on the measurement of the recovery of pelvic floor muscle strength between groups.Secondary outcomes were: 1 hour Pad Test, ICIQ-SF, IIEF-5 and IPSS. Data were obtainedpreoperatively and at 1, 3 and 6 months after surgery. [Results] There was no significantdifference in the demographic data among groups. Greater urinary leakage and pelvic floormuscle weakness in the first month compared to pre treatment improved after 3 and 6 monthspostoperative, without difference among groups. [Conclusion] The muscle strength recoveryoccurs independently of the therapy employed. Pelvic floor exercises or electricalstimulation also did not have an impact on the recovery of urinary continence and erectilefunction in our study.

INTRODUCTION

Despite technical refinements and better knowledge of pelvic and prostate anatomy, there isstill great concern about the functional outcomes after radical prostatectomy (RP) to treatprostate cancer, especially regarding urinary incontinence (UI) and erectile dysfunction(ED) that have great negative impact on quality of life1^,2^,3^,4^,5⁾.

Pelvic floor muscles can play a crucial role in the mechanism of male urinary continenceand their strength is also related to erectile function. The contraction of ischiocavernosusand bulbocavernosus muscles may cause an increase in intracavernous pressure improvingpenile rigidity6^,7^,8^,9^,10^,11^,12^,13^,14⁾. The bulbocavernosusmuscle also compresses the deep dorsal vein of the penis to prevent venous leak during theerection process15⁾. However, theimportance of pelvic floor muscle rehabilitation in the recovery of erectile function is notwell elucidated.

Recently, there has been an increasing interest on the action of the pelvic floor musclesas a possible predictor for the recovery of urinary continence and erectile function inpatients undergoing RP. Therefore, preoperative evaluation of pelvic floor muscle strength(PFMS) can also be an important factor to detect the risk of UI and ED post prostatectomy,as well as determine the effectiveness of physical therapy resources. In the presentrandomized, prospective study, the effect of electrical stimulation (ES) and pelvic floormuscle training (PFMT) was investigated after RP on pelvic floor muscle strength, urinaryincontinence and erectile function in men with prostate cancer treated by radicalprostatectomy.

SUBJECTS AND METHODS

One hundred and twenty-three incontinent males, submitted to RP, by a team of experiencedsurgeons from a cancer center hospital, were studied in a prospective controlled trial. Thisstudy was approved by the Medical Research Ethics Committee of the Barretos Cancer Hospital(Protocol CEP 273/2010) and registered in Clinical Trials (www.clinicaltrials.gov)NCT02226237, moreover, all patients gave their informed consent. The protocol for theresearch project has been approved by a suitably constituted Ethics Committee of theinstitution within which the work was undertaken and that it conforms to the provisions ofthe Declaration of Helsinki.

The eligibility criterion was set to patients who presented higher than 2 g in a 1 h-padtest 1 month after RP. Exclusion criteria were: prior pelvic floor muscle dysfunction(urinary or fecal incontinence), stenosis of the anastomosis or not being able to completethe protocol for any reason. No patient had received preoperative radiotherapy orneoadjuvant hormonal blockade.

A computer-generated random list of group assignments was prepared and was blocked with arandom block size, to reduce the possibility of guessing the next assignment. Assignment wasplaced in numbered opaque envelopes and sealed. Envelopes were opened by an individual notdirectly involved with the study. Only one researcher physiotherapist (A.CEL) was informedabout the randomization of the patients and was the one who performed the interventions. Theother evaluators in the study were all blind.

Patients were randomized 1 month after surgery and only one physiotherapist responsible forthe interventions was aware of the group to which the patient was assigned. At that verymoment patients were evaluated for their urinary continence. Patients with minimal loss(less than 2 grams) were considered continents and were not included in our analysis. On theother hand, 77.5%, 73% and 81% of the cases presented moderate and severe UI and wereallocated into groups G1, G2 and G3, respectively.

Patients were randomly distributed into 3 groups 1 month after radical prostatectomy:

Group 1 (Control n=40): Patients assigned to this group received only the routineinstructions about the postoperative period at the time of hospital discharge, given by theUrology and Nursing staff. No type of treatment or orientation of home exercises wasperformed in this group.

Group 2 (Guideline n=41): Patients randomized to this group were instructed to performthree types of home exercises to strengthen the pelvic floor, which are described below: Indorsal decubitus, with flexed lower limbs, perform contraction of the pelvic floor, followedby relaxation. The targeted movements were:

1) Elevation of the hip (bridge), then relaxing muscles while lowering the hip;

2) Contraction of the thigh adductors, “pressing” a ball, then relaxing;

3) Pelvic floor contraction and relaxation during inspiration and expiration,respectively.

Patients in this group were instructed and encouraged to perform these three exercises athome two to three times a day until they completed 6 months of postoperative period.

Group 3 (Electrical stimulation n=42): Patients in this group were also instructed toperform the same home exercises as group G2 group, and also received analelectro-stimulation therapy, always with the same physiotherapist twice a week for 7 weeks,totalling 14 sessions. Anal electrical stimulation was performed using the equipment DualpexUro 961, Quark^® (Registration at Anvisa number 80079190018) using the followingparameters: frequency: 35 Hz; pulse width: 1 milliseconds; rise time: 2 seconds stimulusduration: 6 seconds; fall time: 2 seconds; standing time: 12 seconds. Intensity wasmodulated to promote visible pelvic floor muscle contraction with no discomfort to thepatient.

All patients were evaluated preoperatively and at 1, 3, and 6 months after RP using thefollowing objective methods and validated questionnaires in Portuguese: 1-hour Pad Test asrecommended by the International Continence Society16⁾, evaluation of pelvic floor muscle strength, using a perineometerby one physiotherapist (blind to randomization), quality of life (QoL) using ICIQ-SF17⁾, erectile function using IIEF-518⁾ and urinary symptoms using IPSS. Allmeasurements were applied by a blind researcher.

One hour Pad Test results were classified according to Laycock & Green classification:0 to 2 grams: dry; 3–10 grams: light urinary loss; 11 to 50 grams: moderate urinary loss;>50 grams: severe urinary loss19⁾.

To evaluate the pelvic floor muscular strength (PFMS) a digital perineometer (DM01 model,Dynamed^®) was used with a rectal balloon, with an unlubrificated condom andfilled with air using a Plastipack syringue (Becton Dickinson^®, São Paulo,Brazil), which allowed contact with the anal wall. For such measure, patients were kept in asupine position with bent legs. After the introduction of the balloon, the equipment wasimmediately zeroed, and the patient was asked to hold three PFM contractions for as long aspossible, with approximately 30-second rest intervals between them. Three measurements weremade and an average was considered. The measurement was registered in cmH₂O.

The brand and model of the perineometer used in this study is a reference in our studygroup20^, 21⁾.

The sample size of a minimum of 40 individuals per group was set considering 10% estimationerror (90% sample power) for the primary and secondary endpoint22⁾. Allowing for dropouts and withdrawals, 237 subjects wererecruited.

Participants who dropped out or withdrew for reasons unrelated to treatment protocol (ie,moving to another location) were classified as dropouts. Patients who completed the followup period were analyzed in the groups that they were initially allocated.

Parametric analysis of variance complemented by Tukey test and nonparametric techniquescomplemented by Dunn’s test were used. All tests were discussed at the 5% level ofsignificance.

The primary outcome assessment was based on the measurement of the recovery of pelvic floormuscle strength obtained by perineometry between groups. Perineometry is an objectivemeasure of pressure, which can be obtained in cmH₂O or mmHg. In this study, themaximal peak of each contraction was registered in cmH₂O. Perineometry isconsidered an objective form of muscle strength measurement, frequently used in studiesinvolving the strength of the female pelvic floor. In men undergoing prostatectomy, there isstill no evidence of the relationship between recovery from urinary continence or erectilefunction with recovery of muscle strength from the male pelvic floor.

Secondary outcomes were: 1 hour Pad Test (urine loss), ICIQ-SF score (quality of life),IIEF-5 score (erectile function), and IPSS score (urinary symptoms).

The 1 hour Pad Test is recommended by the International Continence Society (ICS)16⁾ and is an objective measurement of urineloss. It is a practical test and of easy reproducibility.

ICIQ-SF is a simple and brief instrument that assesses the impact of urinary incontinenceon the patient’s quality of life and qualifies urinary loss in patients of both genders. Itwas validated for the use in Portuguese by Tamanini et al. in 200417⁾.Its score ranges from 0 to 21, with 0 being the absence ofan impact of urinary incontinence on quality of life.

IIEF-5 is a summary version of the International Index of Erectile Function (IIEF) and wasdeveloped to diagnose the presence and severity of erectile dysfunction (ED). It is aspecific instrument that evaluates the results of a treatment based on the individual’s ownperception about their sexual life. Its score ranges from 1 (Severe Erectile Dysfunction) to25 (Absence of Erectile Dysfunction)18⁾.

IPSS is the most widely used and internationally accepted method for evaluating urinarysymptoms. It is a good indicator of the degree of discomfort and effect on quality of lifein patients with lower urinary tract symptoms. Their score ranges from 0 (mild symptoms) to35 (severe symptoms).

RESULTS

From October 2011 to September 2014, 237 patients were prospectively screened. Of these, 82refused to participate and 23 patients did not satisfy the inclusion criterion. One hundredand thirty-two patients were randomized and after an exclusion criteria-based step, onehundred and twenty-three post-prostatectomy incontinent men were studied (Fig. 1). There was no significant difference on clinical and pathological variables amongthe studied groups and 77.5%, 73% and 81% presented moderate and severe RPUI and wereassigned to groups G1, G2 and G3, respectively. Therefore, groups were consideredhomogeneous.

The average age was 57.3 (± 6.5), 58.0 (± 5.7) and 58.5 (± 5.4), respectively. The bodymass index between groups was, respectively, 26.4 (± 4.1), 27.1 (± 4.0) and 26.9 (± 4.2). Inthe three study groups, most patients had pathological staging classified into pT2c (67.5%,61% and 64.3%). During the follow-up period of the study (6 months), no patient had lymphnode or distant recurrence. Table 1 shows an overview of the clinical conditions of the patients.

There was a significant worsening of PFMS in all groups in the first month after surgerycompared to preoperatively, demonstrating the impact of surgery on this muscle group. At theend of the follow-up, no statistical difference was observed in muscle strength measurementbetween different groups (p>0.05) (Table2).

In the 1 hour-Pad Test, there was a significant worsening of incontinence, in all groups inthe first postoperative month in comparison to different moments, demonstrating objectiveworsening of urinary loss in the first month after surgery. On the other hand, we alsoobserved a spontaneus recovery of urinary leak in all groups in the third and sixth months.However, there was no statistical difference among groups in different moments (p>0.05)(Table 3).

The measure of quality of life (ICIQ-SF score) showed a significant worsening in all groupsin the first month after surgery compared to preoperatively (p<0.05). This worsening wasmaintained until the sixth month of evaluation with no significant difference between groupsG1, G2 and G3 at the end of follow-up (p>0.05) (Table 4).

In the assessment of erectile function (IIEF-5 score), there was a significant worsening inall groups in the first postoperative month compared to initial evaluation. We also noted asignificant, though partial, improvement in the score of each group in the sixthpost-operative month compared to the first post-operative month. There was no differenceamong different groups at any time (Table5).

In the evaluation of IPSS, there was a significant improvement in the sixth monthevaluation in relation to preoperative in all groups (p<0.05). However, there was nosignificant difference between the groups, even at the end of follow-up: 4 (0–18), 4 (0–23)and 2.5 (0–27) in G1, G2 and G3, respectively (Table6).

DISCUSSION

This study evaluated the impact of different forms of pelvic floor muscle rehabilitation inpatients undergoing radical prostatectomy. Different types of physical therapy did notinfluence the recovery of urinary incontinence and erectile dysfunction. In all groups weobserved an impairment of all studied variables (pelvic floor muscle strength, 1-hour PadTest, ICIQ-SF and IIEF-5) except IPSS scores at 1 month after surgery with recovery at 3months, sustained at 6 months for 1-hour Pad Test and pelvic floor muscle strength and at 6months for ICIQ-SF, IIEF-5 and IPSS, regardless of the physiotherapeutic intervention.

Despite this, in agreement with other authors12^,23⁾ we have observed an associationbetween recovery rates of urinary incontinence and increasing of pelvic floor musclestrength, suggesting an effect of pelvic floor muscles on urinary incontinence recovery,which was more complete than the erectile dysfunction recovery.

Nowadays, the role that pelvic floor muscle strength plays on the recovery of urinaryincontinence and erectile dysfunction is still unclear. Perhaps the most important factor ofthese complications is the direct damage to the sphincter and vascular-nervous bundle duringthe radical prostatectomy. Although, we observed a weakness of perineal muscles in the firstpostoperative month in all groups, there were similar recovery rates in all groups.

The objective evaluation of urinary loss in the first month after radical prostatectomyfound that most patients had moderate and severe urinary incontinence, with no significantdifference among groups, demonstrating that these are homogeneous groups.

While our findings were coincident with the results observed in a meta-analysis by Zhu etal.1⁾, in which the authors concludedthat the use of electrical stimulation associated with pelvic floor muscle training did notprevent urinary incontinence. A late benefit for pelvic floor muscle training was observedby other authors and the preoperative levels returning in the third month, maintained untilthe sixth month are in disagreement with other study10⁾ in which objective improvement in urinary incontinence post radicalprostatectomy was observed earlier.

In erectile function, there was a significant worsening after surgery with no substantialrecovery in all groups. Nevertheless, other authors14^, 24⁾ have observed improvementin erectile function after physiotherapeutic treatment. Perhaps the main limitation of ourstudy is in the fact that urinary incontinence did not improve in all groups, interferingwith erectile dysfunction recovery since urinary incontinence can directly affect sexualrelations attempts, and consequently, sexual satisfaction in this population.

We found a worsening in the quality of life (ICIQ-SF score) in the first monthpostoperatively in all groups, demonstrating the impact of surgery on the patients studied,with improvement attributed to the time effect. Yamanishi et al.25⁾ showed similar results in a controled study. Other authorshave demonstrated the importance of using ICIQ-SF questionnaire validated in Portuguese tostandardize the results obtained in relation of urinary incontinence influencing quality oflife26⁾.

In the literature, some authors have used the IPSS score for evaluation of urinary symptomsin men after RP. Significant improvement at the end of follow-up compared to thepre-operative period was observed in our study, in agreement with other authors27⁾.

None of the patients involved in this study had previously performed any kind ofphysiotherapy for the pelvic floor muscles in their previous history. Perhaps a limitationto be considered in our study is the absence of an instrument to measure the patient’sadherence to perform the exercises at home in the group that received only guidance for homeexercises.

Although there is no knowledge of the patients nerve sparing, or use of PDE5 inhibitorspostoperatively, there is no reason to believe that in the randomization such features mightbe unbalanced between study groups.

Our study is not without limitations, though prospective randomized, it is relativellysmall and limited to the techniques used in the pelvic floor muscle trainnig. Furtherstudies are necessary considering larger cohorts and different interventions.

Our results suggest that muscle strength recovery occurs independently of the therapyemployed. The time factor seems to be the most important marker. Pelvic floor exercises orelectrical stimulation also did not have an impact on the recovery of urinary continence anderectile function in our study.

Funding

This study was funded by the Foundation for Research Support of the State of São Paulo(FAPESP), under registration number 2011/12154-7.

Conflict of interest

There are no conflicts of interest in the study.

REFERENCES