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Keywords:

  • Electrical stimulation;
  • Magnetic innervation;
  • Nursing;
  • Radical prostatectomy;
  • Urinary incontinence

ABSTRACT

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

Nurses use several conservative methods for treating urinary incontinence after radical prostatectomy. Functional electrical stimulation (FES) has a recognized role, while extracorporeal magnetic innervation (ExMI) is still under evaluation in the international guidelines. Few data are available in literature, regarding comparisons between these two treatments. The aim of the study is to compare electrical stimulation and magnetic innervation for treating urinary incontinence after radical prostatectomy. Twenty-two patients treated with ExMI and 18 treated with FES were enrolled in a retrospective study. ExMI was available for 6 weeks; the number of times ExMI was required by the patients to reduce their leakages to 10 g/d or less was compared. The groups had comparable age and body mass index. Initial leakages showed clinically relevant differences (median = 80 g/d in the ExMI patients and 150 g/d in the FES group). After 6 weeks, 71·9% of ExMI patients and 29·2% of FES patients had completed rehabilitation. The difference was statistically significant even after adjusting the analyses for initial leakages (p = 0·008). Six patients treated with ExMI had already undergone FES, with no clinically relevant results after five sessions (leakages reduction <50 g/d). The difference remained even after removing the data of these patients from the analysis (p = 0·004). Both FES and ExMI produce muscle strengthening, which is just one step of rehabilitation. Our findings suggest the possibility of using ExMI instead of FES to reduce the times required to improve muscular performance. Pelvic muscle exercises remain essential to develop the ability to automatically perform the contractions needed to avoid leakages.


RATIONALE

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

Radical prostatectomy (RP) is the surgical removal of the whole prostate and the vesciculae. It has several known drawbacks, such as erectile dysfunction (Benson et al., 2012) and urinary incontinence (UI) (Buckley et al., 2012). UI has been defined by the International Continence Society as ‘any involuntary urine loss reported by the patient, or a positive result on a stress test’ (Abrams et al., 2002). Post-RP UI is mainly related to intra-operative damage of the striated urethral sphincter, which is recognized as an important mechanism of continence in men (Stafford et al., 2012). Prevalence of post-prostatectomy UI in literature ranges from 2% to over 60% due to different definitions of continence and discrepancies among the assessment times chosen by the authors (Campbell et al., 2012). These percentages increase when incontinence is reported by patients: in a recent study on 1616 patients (Peterson and Chen, 2012) 90·3% of patients reported UI more than 1 year after prostatectomy.

The International Continence Society recommends conservative management as the first-line intervention for UI in patients without denervation (Abrams et al., 2010). The term ‘conservative management’ refers to pelvic floor rehabilitation, performed without drugs or surgery. The three steps that patients must follow in a rehabilitation process are developing self-awareness of their own pelvic muscles, improving their pelvic muscular performance (strength, endurance and resistance) and developing the ability to automatically perform contractions of the pelvic muscles, to constrict the urethra in situations at risk for urine leakages (e.g. when intra-abdominal pressure raises) (Bortolami, 2009). Conservative treatments include pelvic floor muscle training (PFMT), functional electrical stimulation (FES) and extracorporeal magnetic innervation (ExMI) (Campbell et al., 2012).

After RP, continence recovery is related to perineal body tone recovery (Rigatti et al., 2012); the goal of strengthening the pelvic muscles, rising from this evidence, can be achieved in several ways. Pelvic floor muscle exercises, first proposed by Arnold Kegel for women (Kegel, 1948), can lead to improved performance of the laevator ani group, through the repetition of voluntary contractions performed under the guidance of a rehabilitator (e.g. nurse, physiotherapist). Contractions are performed according to precise sequences of work and recovery times, in specific body positions. Daily repetitions of the exercises allow patients to develop contraction automatisms in situations at risk for leakages (for instance, while the patients get up from sitting, coughs or laughs). Pelvic floor exercises are considered a front-line treatment for UI (Abrams et al., 2009).

Functional electrical stimulation (FES) is a passive rehabilitation technique that uses an electric current, delivered to the pelvic muscles of the patient through a probe inserted in the anus. The probe is connected to a machine that produces specifically designed electric currents, with parameters that can be managed by the rehabilitator (e.g. intensity, duration of each stimulation, duration of recovery times between stimulations, total treatment time). The stimulation can also be performed with self-adhesive surface electrodes attached to the skin, between the patient's scrotum and anus. The electrodes can be used as an alternative to the probe, in patients with external haemorrhoids (Bortolami, 2009). The intention of electrical stimulation is to facilitate the contraction of the periurethral striated muscle (Campbell et al., 2012).

ExMI is a passive, non-invasive rehabilitation technique. It uses an armchair equipped with a device generating a magnetic field, placed under the seat. The patient sits in the armchair with his clothes on; the magnetic field induces an electric field, which causes depolarization and contraction of the pelvic muscles. The field intensity can be adjusted by the therapist through specific controls of the machine; this allows complete control on the intensity and duration of the stimulation.

The final effect of both FES and ExMI is muscle strengthening, through contractions induced by directly applied electric currents (FES) or the indirect action of a magnetic field (ExMI).

Overall, these conservative methods for treating UI after RP still need to be investigated for several reasons. The available literature is based on different definition of continence, making it difficult to compare the results (Campbell et al., 2012). As regards PFMT, even if the recommendations regarding this treatment are supported by the clinical improvements achieved in many trials by samples of patients, the results of the available trials show wide confidence intervals. This prevents the possibility of generalizing the conclusions (Campbell et al., 2012). The clinical trials regarding ExMI have been conducted on small samples. ExMI is currently ‘not rated’ in the latest European guidelines because of the lack of evidence (Thüroff et al., 2011). In particular, there is a lack of evidence regarding the application of ExMI in post-prostatectomy UI. In PubMed, the string ‘Extracorporeal magnetic innervation’ with the limits ‘All adults 19+ years’ and ‘Male gender’ returned only one article regarding ExMI in post-RP UI (Yokoyama et al., 2004). The authors pointed out the positive effects of ExMI and FES on post-RP continence recovery when compared with no treatment. However, the sample size was very limited (12 patients in each of the three groups). Further investigation is therefore needed to evaluate the actual efficacy of magnetic innervation compared to electrical stimulation in the treatment of UI after RP.

AIM OF THE PROJECT

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

The aim of this study is to compare the effects of ExMI and FES on involuntary leakages of urine in post-RP patients.

SAMPLE

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

We retrospectively enrolled a sample of 40 patients, who were under treatment for stress UI in the urology outpatients' service of a teaching hospital in 2010, after RP for organ-confined cancer. All patients had undergone urodynamic testing to assess the type of UI. Patients who were undergoing radiotherapy or had prostheses sensitive to magnetic fields were excluded.

In the above-mentioned service, all patients with post-RP UI are treated first with PFMT, according to the literature recommendations (Abrams et al., 2010). The patients in our sample had been trained in PFMT by a continence nurse.

The ExMI machine has been available for a period of 6 weeks between April and July 2012. Before the arrival of the ExMI equipment, 18 post-RP patients who could not learn the principles of PFMT began treatments with FES, which was already being used at that time. After the arrival of the ExMI equipment, the patients who could not learn the principles of PFMT nor had obtained any clinically relevant results after five sessions of FES (leakages reduction <50 g/d) were candidates for ExMI after a thorough explanation of the treatment. Twenty-two patients accepted and began rehabilitation sessions with magnetic innervation. In both groups, all patients had been performing PFMT without clinically relevant results (leakages reduction <50 g/d) for a median of 5 weeks.

All FES treatments have been administered by using rectal probes (Figure 1), with biphasic currents at 50 Hz for 10 min (first session) or 15 min (from the second session), 6 s of stimulation and 12 s of recovery time. Ramp modulations included in the factory programmes of the machine were applied at the beginning and end of all train of pulses to allow gradual muscular stimulation. Ramp-up times ranged from 20% to 30% of the stimulation time, while ramp-down times ranged from 40% to 50%. These differences in overall times and electric parameters were due to the progression of the FES treatment, according to the rehabilitation programmes of the machine.

image

Figure 1. Rectal probe for functional electrical stimulation (FES).

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The ExMI parameters were pre-set in the machine by the factory. The frequency was 50 Hz, with 5 s of working time, 5 s of rest, 10 min of treatment during the first session and 20 min in the following.

All patients in the two groups received two sessions per week. All treatments have been administered by a continence nurse, who had achieved a university-level certificate of competence in urological rehabilitation.

DATA COLLECTION METHODS

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

In August 2012, data regarding age, incontinence type and urine leakages before and after treatments were retrieved from the nursing records of the outpatients' service. The patients had quantified their leakages by weighing daily pads with a balance provided by the hospital (24-h pad test) (Ostergard, 1996). The treatments were considered successful when patients reported an overall daily leakage of 10 g or less (Smither et al., 2007). As regards ethical issues, the study has been conducted in agreement with the indications of the Helsinki Declaration.

DATA ANALYSIS

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

The Wilcoxon signed-rank test was used to test differences between the groups in terms of age, BMI and leakages before the treatments. Kaplan-Maier's life tables and Cox proportional hazard analysis were used to compare the effects of treatments over time. The statistical significance cut-off was set at 0·05; descriptive statistics are reported with one decimal value, p-values with two. SAS 9.1 for Windows was used to perform the analyses.

RESULTS

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

All patients had stress incontinence. The median ages in the two groups were 70·0 years (FES group: interquartile range, IQR = [67·0; 75·0]) and 68·0 years (ExMI group: IQR = [65·5; 72·0]), with no significant differences (Wilcoxon's test: p = 0·34). The patients had begun rehabilitation after a median of 6 weeks after surgery.

The median body mass indexes were 25·6 kg/m2 (FES group: IQR = [23·4; 26·9]) and 24·8 kg/m2 (ExMI group: IQR = [23·1; 27·0]) with no significant differences (Wilcoxon's test: p = 0·52).

The median urine leakages prior to the treatments showed a clinically and statistically significant difference, being 150·0 g/d in the FES group (IQR = [70·0; 275·0]) and 80·0 g/d in the ExMI group (IQR = [40·0; 100·0]) (Wilcoxon's test: p < 0·01). This difference has been considered during the comparisons between the treatments: during the life table analysis, leakages before treatments have been inserted in the model as covariates in order to evaluate the effects of differences on the rehabilitationoutcomes.

Notwithstanding the difference, magnetic innervation showed a relevant advantage over FES, in terms of time needed to complete rehabilitation. At the beginning of the 6th week, patients who had successfully completed the treatment were 29·2% in the FES group and 71·9% in the ExMI group. This finding was independent from the initial leakage difference: the log-rank test between the two curves, adjusted for initial leakages, returned a p-value of 0·008. The association between initial leakages and rehabilitation outcomes was irrelevant (risk ratio = 0·995).

Six patients in the ExMI group had been treated with FES, without clinically significant leakage reductions (<50 g/d). In order to eliminate this potential bias the analysis was repeated after excluding the six patients from the database. The difference in favour of ExMI remained statistically significant (log-rank test: p = 0·01) and was not affected by the difference between the initial leakages in the two groups (risk ratio = 0·99). Figure 2 shows the difference between the rehabilitation times in the two groups, after the exclusion of the six above-mentioned patients. The FES patient who required the longest treatment period had a leakage of 1200 g/d before treatment. After 28 weeks of electrical stimulation, his 24-h pad test showed a leakage of 750 g/d; FES was suspended, and the patient began non-conservative treatments for UI.

image

Figure 2. Rehabilitation times: functional electrical stimulation (FES) versus extracorporeal magnetic innervation (ExMI) alone.

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CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

ExMI showed a clinically relevant advantage over FES, in the reduction of daily leakages due to stress UI after post-RP. This finding was independent from the difference found in patients' leakages prior to the treatments. A possible explanation could involve the penetration of the magnetic field generated by the ExMI machine in the body tissues. The force lines of the field could reach deep muscular fibres, with enough intensity to induce a current sufficient for contraction, while FES current might reach only the muscular fibres near the region in which the probe is placed. This could result in the simultaneous contraction of more fibres during ExMI, in comparison to the FES treatment. However, this is just a supposition, and needs confirmation by appropriate electromyography studies.

The men who accepted the FES treatments, after an initial period of embarrassment, responded well to the use of the probe. The rehabilitation nurse played a fundamental role in helping them cope with the invasive treatment by guaranteeing their privacy, talking to them, and sometimes joking and playing down the situation. This helped the patients feeling at ease in situations they perceived as very delicate, and probably avoided several potential dropouts.

Given the small sample size and the retrospective study design, this finding needs confirmation by larger, randomized study; considering the relevant difference in recovery times, we think our results deserve further investigation.

Muscle strength is just one of the prerequisites for good rehabilitation outcomes, because patients need to learn how to automatically contract their pelvic muscles in order to avoid leakages in situations at risk. The results of this study suggest the possibility of using ExMI in the initial steps of the rehabilitation process, in order to shorten the period required for improving muscular performance (tone, strength and endurance). Rehabilitation must be individualized, because the situations which lead to leakages are not the same for all patients. Therefore, adapting the exercises to specific patients' needs is a common activity for a rehabilitation nurse. Shortening the time required for strengthening could save valuable time, that rehabilitators could dedicate to further personalization of the rehabilitation sessions, according to the needs of their patients.

CONFLICT OF INTEREST

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

The authors declare no conflict of interest. No funds or grants were used for this study. The picture reported as Figure 1 is the authors' own work.

AUTHOR CONTRIBUTION

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES

S. T. and C. R. involved in study design; C. R. collected the data; S. T. and C. R. analysed the data; S. T., C. R., A. D. and E. M. prepared the manuscript.

WHAT IS KNOWN ABOUT THIS TOPIC

  • Among conservative treatments for post-prostatectomy urinary incontinence, functional electrical stimulation plays a role.
  • The efficacy of extracorporeal magnetic innervation in unclear in literature; this treatment in still ‘not rated’ in the international guidelines.
  • Only one study has compared magnetic innervation and electrical stimulation in patients with urinary incontinence after radical prostatectomy.

WHAT THIS PAPER ADDS

  • ExMI seems to shorten the time required to reduce daily leakages under the 10 g cut-off, if compared to FES, even in the presence of clinically relevant differences between the initial leakages in the two groups.
  • This suggest the possibility of saving time to personalize the rehabilitation programmes, with specific pelvic muscle exercises aiming at the specific continence difficulties of each patient.

REFERENCES

  1. Top of page
  2. ABSTRACT
  3. RATIONALE
  4. AIM OF THE PROJECT
  5. SAMPLE
  6. DATA COLLECTION METHODS
  7. DATA ANALYSIS
  8. RESULTS
  9. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE
  10. CONFLICT OF INTEREST
  11. AUTHOR CONTRIBUTION
  12. REFERENCES
  • Abrams P, Cardozo L, Fall M, Griffiths D, Rosier P, Ulmsten U, van Kerrebroeck P, Victor A, Wein A. (2002). The standardisation of terminology of lower urinary tract function: report from the Standardisation Sub-committee of the International Continence Society. American Journal of Obstetrics and Gynecology; 187 (1): 116126.
  • Abrams P, Cardozo L, Wein A. (2009). Incontinenza. Vol. 1–2. Milan: Edi.Ermes.
  • Abrams P, Andersson KE, Birder L, Brubaker L, Cardozo L, Chapple C, Cottenden A, Davila W, de Ridder D, Dmochowski R, Drake M, Dubeau C, Fry C, Hanno P, Smith JH, Herschorn S, Hosker G, Kelleher C, Koelbl H, Khoury S, Madoff R, Milsom I, Moore K, Newman D, Nitti V, Norton C, Nygaard I, Payne C, Smith A, Staskin D, Tekgul S, Thuroff J, Tubaro A, Vodusek D, Wein A, Wyndaele JJ. (2010). Fourth International Consultation on Incontinence Recommendations of the International Scientific Committee: evaluation and treatment of urinary incontinence, pelvic organ prolapse, and fecal incontinence. Neurourology and Urodynamics; 29 (1): 213240.
  • Benson CR, Serefoglu EC, Hellstrom WJG. (2012). Sexual dysfunction following radical prostatectomy. Journal of Andrology; 33 (6): 11431154. DOI: 10.2164/jandrol.112.016790.
  • Bortolami A. (2009). Riabilitazione del Pavimento Pelvico. MIlano: Masson.
  • Buckley BS, Lapitan MCM, Glazener CM. (2012). The effect of urinary incontinence on health utility and health-related quality of life in men following prostate surgery. Neurourology and Urodynamics; 31 (4): 465469.
  • Campbell SE, Glazener CM, Hunter KF, Cody JD, Moore KN. (2012). Conservative management for postprostatectomy urinary incontinence. Cochrane Database of Systematic Reviews (Online); 1. DOI: 10.1002/14651858.CD001843.pub4.
  • Kegel AH. (1948). Progressive resistance exercise in the functional restoration of the perineal muscles. American Journal of Obstetrics and Gynecology; 56 (2): 238248.
  • Ostergard D. (1996). Urogynecology and Urodynamics: Theory and Practice. 4th edn. Baltimore: Williams & Wilkins.
  • Peterson AC, Chen Y. (2012). Patient reported incontinence after radical prostatectomy is more common than expected and not associated with the nerve sparing technique: results from the Center for Prostate Disease Research (CPDR) database. Neurourology and Urodynamics; 31 (1): 6063.
  • Rigatti L, Centemero A, Lughezzani G, Larcher A, Giraudo D, Scapaticci E, Sangalli M, Lista G, Lazzeri M, Montorsi F, Rigatti P, Guazzoni G. (2012). The relationship between continence and perineal body tone before and after radical prostatectomy: a pilot study. Neurourology and Urodynamics; 31 (4): 513516.
  • Smither AR, Guralnick ML, Davis NB, See WA. (2007). Quantifying the natural history of post-radical prostatectomy incontinence using objective pad test data. BMC Urology; 7: 2.
  • Stafford RE, Ashton-Miller JA, Sapsford R, Hodges PW. (2012). Activation of the striated urethral sphincter to maintain continence during dynamic tasks in healthy men. Neurourology and Urodynamics; 31 (1): 3643.
  • Thüroff JW, Abrams P, Andersson KE, Artibani W, Chapple CR, Drake MJ, Hampel C, Neisius A, Schröder A, Tubaro A. (2011). EAU guidelines on urinary incontinence. European Urology; 59 (3): 387400.
  • Yokoyama T, Nishiguchi J, Watanabe T, Nose H, Nozaki K, Fujita O, Inoue M, Kumon H. (2004). Comparative study of effects of extracorporeal magnetic innervation versus electrical stimulation for urinary incontinence after radical prostatectomy. Urology; 63 (2): 264267.