Neuromodulation and urodynamics in lower urinary tract symptoms Groenendijk, P.M.

Neuromodulation and urodynamics in lower urinary tract symptoms

Groenendijk, P.M.

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Groenendijk, P. M. (2008, December 9). Neuromodulation and urodynamics in lower urinary tract symptoms. Retrieved from

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Chapter 7

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Extracorporeal Magnetic

Innervation therapy: Assessment of clinical efficacy in relation to urodynamic parameters

P.M. Groenendijk, M. Halilovic, D.D. Chandi, J.P.F.A. Heesakkers, P.J. Voorham-van der Zalm and A.A.B. Lycklama à Nijeholt

Scand J Urol Nephrol 2008; 42(5)

Abstract

Objective: clinical efficacy and urodynamic changes in women treated by extracorporeal magne- tic innervation therapy (ExMI) were studied.

Materials and methods: women, presenting with urge, stress and mixed urinary incontinence were included in a prospective study. ExMI was applied by an ‘electromagnetic chair’. To do- cument clinical efficacy, a voiding diary and visual analogue scale were completed prior to and after treatment, together with a pad test. Detrusor overactivity (DO) and urethral instability (URI) were urodynamically documented. Clinical success was defined if more than 50% improvement in symptoms was observed.

Results: sixteen patients were included. At baseline, DO was observed in 10 patients, in 12 pa- tients URI was seen. DO did disappear at follow-up in 60%, in 66% a decrease in URI was seen.

No significant clinical improvement was seen at follow-up.

Conclusion: although significant changes in urodynamic variables were observed, no significant improvement in clinical efficacy was seen after ExMI.

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Introduction

The prevalence of voiding dysfunctions will continue to rise. Reason for this is an increase in expected life span for people in the western world. Furthermore, increasing interest in the media and general public in voiding problems will lead to a greater demand for treatment.

Complaints of an overactive bladder (OAB) have a large impact on patient’s quality of life. For tre- atment, different modalities may be considered, like pharmacotherapy, behavioural therapy, neu- romodulation, and even invasive surgical procedures [1]. All these options have drawbacks, with a high number of complications for some of them. Unfortunately, clinical results of conventional treatment modalities are disappointing for a relatively high percentage of patients presenting with voiding dysfunctions. New non-invasive treatment modalities, with minor side effects are intro- duced. The value of these modern techniques for daily practice and their mode of action however are yet not fully understood [2]. Pulsed magnetic technology is in use for the stimulation of pelvic floor muscles. Nerves are most sensitive to depolarization by the changing magnetic field, causing a propagating impulse that provoke muscle contraction.

A new, non-invasive neuromodulative technique with almost no side effects is extracorporeal magnetic innervation therapy (ExMI). Published results of ExMI show various success rates. The value of urodynamics for both patient selection and evaluation of success is not clear [3]. We studied both clinical efficacy and urodynamic changes at baseline and after ExMI treatment in patients presenting with various voiding complaints.

Materials and methods

Women with a history of urge urinary incontinence, stress and mixed incontinence were included in this prospective study of the electromagnetic chair (Neocontrol®, Neotonus, Marietta, Geor- gia, USA). Before inclusion, urine cultures were taken to rule out (recurrent) urinary tract infecti- ons, patient’s medical history (drug usage, prior treatment) was noted and a physical examination was performed. Cystoscopy was done to exclude intravesical abnormalities. Exclusion criteria included pregnancy, a history of radiotherapy and malignancy, implantation of metals including a pacemaker, or physiotherapy during the study. A voiding diary, pad test and visual analogue score (VAS) were completed at baseline and one week after the last treatment to document voiding patterns. A VAS with a scale of 0-10 from ‘very good’ (10) to ‘terrible’ (0) was used to estimate the quality of life concerning voiding disorders.

Cystometry was performed with the MMS UD-2000 (Medical Measurement Systems, Enschede, the Netherlands) and a Gaeltec (Gaeltec Ltd, Dunvegan, Isle of Skye, Scotland) CTU/2E/L-4 12F catheter, with 3 urethral pressure sensors and 1 bladder sensor. Urethral instability (URI), Detrsuor overactivity (DO) and first sensation of filling (FSF) during filling cystometry were noted. Urethral pressure variations of more than 15 cm H₂O detected on all 3 urethral pressure recordings du- ring filling cystometry were considered pathological. Pressure variations of 16-30 cm H₂O were classified as minor, and those exceeding 31 cm H₂O were considered as major. Pressure variati- ons related to artefacts (mechanical factors, movement of the patient or the catheter, vascular

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pulsations) were disregarded. Urethral pressure variations were studied separately from possible concurrent bladder pressure fluctuations. All other definitions were used according to the guide- lines of the ICS [4].

During treatment, patients sat in the Neocontrol chair (Neocontrol®, Neotonus, Marietta, Geor- gia, USA). Stimulation is provided by an electromagnetic generator in the seat of the chair, con- trolled by an external unit, creating pulses of 275 μs. Frequency and amplitude can be changed by the clinician, thereby controlling the magnitude and strength of the magnetic field. The effect is greatest in the centre of the field and therefore the perineum must be in the middle of the seat. In this position, patients felt the highest contraction of the anal or vaginal sphincter during stimulation. Stimulus intensity was increased up to the limit of patient tolerability. No electricity enters the patient’s body from the device, only magnetic flux. Patients were treated twice a week for 8 weeks. During each session, patients with urge urinary incontinence were stimulated for two episodes of 10 minutes at 10 Hz, with an interval of 1 min. Patients presenting with stress incon- tinence were treated with two episodes of 10 min at 50 Hz, with an interval of 1 minute, while patients with mixed incontinence were treated for 10 min at 10 Hz and 10 minutes at 50 Hz.

Treatment was considered as successful if incontinent episodes, loss of urine, or if voiding fre- quency decreased by more than 50%.

Results

Sixteen female patients, 13 presenting with urge urinary incontinence, 1 with stress incontinence and 2 with mixed incontinence were included and fulfilled the study endpoints. Mean age was 51 years (range 42-76).

Clinical efficacy and Quality of Life

There were no significant differences in voiding diary, pad test and VAS before and after treat- ment. For all patients, a decrease of mean urine loss of 24% was found, as measured by pad test.

Mean urine leakage at baseline was 128 ml (range 3-511), after ExMI this was 103 ml (range 3-439). Voiding frequency did not show a significant improvement after treating with ExMI.

Average voiding frequency pre-treatment was 12, after ExMI treatment an average voiding fre- quency of 13 was found. Quality of life related to micturition, as measured by VAS on a range from 0 (terrible) to 10 (excellent) did not improve. Before treatment a mean score of 6 was noted, after treatment this was 5.5.

Urodynamic studies

DO defined according to the guidelines of the ICS, was seen in 10 patients on urodynamic investi- gation prior to treatment. Minor urethral pressure variations with relatively low amplitude (16-30 cm H₂O) were noted in 8 patients, 4 patients showed major urethral pressure variations exceeding 31 cm H₂O. In all patients presenting with DO, URI was present. Mean baseline FSF was 124 ml (range 31-341) that increased to 183 ml (range 19-400) at follow-up. Of the 8 patients with minor URI at baseline, no urethral pressure variations were seen in 6 at follow-up, in 1 minor URI

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113 was still present, while in the other patient, the amplitude of urethral pressure variations changed from minor URI to major URI. In 4 patients with baseline major URI, URI was still observed in 2 at follow-up, in the other 2 patients no urethral pressure variations were seen. For one patient, who did not demonstrate URI at baseline, major URI was observed after treatment (Table 1). For the patients with urodynamically observed diminished URI after ExMI therapy, there was no positive effect on the clinical outcome by means of voiding diary data or VAS.

Table 1. Urethtral and detrusor behaviour on urodynamic testing, before and after therapy (DO; detrusor overactivity, URI; urethral instability)

Urodynamics at baseline

Urodynamics after ExMI treatment

DO URI

10 absent 4

major 4

4 absent 11

major 4

minor 8 minor 1

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Discussion

Our patient population consisted of 16 females with symptoms of urge, stress and mixed urinary incontinence. We did not find significant benefit of ExMI treatment for quality of life, pad test and voiding diary parameters, or correlation between urodynamic variables and clinical success.

Urodynamic parameters improved after therapy, this however was not related to the clinical out- come.

Non-invasive ExMI therapy is a relatively new technique, with advantages over other neuromo- dulative treatment options. ExMI said to modulate the sacral nerves without invasive vaginal or anal devices [3]. Side effects are minor and no complications are known. However, ExMI is not widely used in daily practice. Reason for this may be economical, since ExMI treatment is rather expensive [3]. Furthermore, long-term efficacy of ExMI is still unclear. The discussion still conti- nues about the efficacy of ExMI with different success percentages reported varying from 44 to 69% [3,5,6]. Only few studies on ExMI report on both urodynamic urethral and detrusor impro- vement after therapy and the relation to clinical efficacy.

We did not find significant clinical benefit for our group of patients. Chandi et al. reported an objective improvement in 58% of 24 patients treated for urge urinary incontinence and mixed incontinence. Significant clinical improvement was only seen in patients with urge incontinence.

Urodynamic parameters did not significantly change after ExMI [3]. For patients with stress in- continence, Galloway et al. reported a significant decrease in urinary leakage measured by pad test, together with a decrease in frequency of leakages. Their urodynamic studies showed DO prior to treatment in 5 patients at follow-up this observation was only present in 1 [6]. Yamanishi et al. found a significant improvement in maximum urethral closure pressure, urgency and QoL after ExMI [7,8]. Fujishiro et al. reported a beneficial effect of magnetic stimulation (15 Hz with 50% intensity) for stress incontinence patients over a sham group [9]. Improvement rate was 74% in the active stimulation group, and 32% in the sham stimulation group on the short-term;

long-term effects are unclear.

The effect of ExMI on pelvic floor function (i.e. pelvic floor rest tone, the basal amplitude re- gistered on electromyography and voluntary or involuntary contraction strength) is studied by Voorham-van der Zalm et al. Again, ExMI did not change pelvic floor function in a group of 74 patients, presenting with a history of urge urinary incontinence, urgency/frequency, stress incontinence, mixed incontinence and defecation problems; the ‘chair’ may be suitable to train awareness of the location of the pelvic floor, but the need for active pelvic floor muscle exercises still remains [5]. In accordance with most presented studies, patients a wide variety of complaints (both men and women) were studied by Voorham-van der Zalm et al.

Prevalence and clinical importance of urethral pressure variations are under debate. In time, the ICS failed to define the observed urethral pressure variations [4]. URI is reported to occur with

115 different prevalence’s in patients with voiding symptoms [10]. As well, it is known that URI may be present in healthy volunteers; a prevalence of 7-14% is found in females without voiding complaints [11]. Prevalence of URI and DO was high in our study group. For patients presenting with different voiding disorders at our department, this is seen before. Venema and Kramer found unstable urethral behaviour in 47 (66%) of 71 incontinent female patients, DO was present in 17 (24%) of these patients [12]. In patients treated with sacral neuromodulation (SNM) at our de- partment, URI was seen in 95%. A significant decrease in URI after SNM was observed, however disappearance of DO was not related to SNM therapy success. URI appeared a better parameter to predict the outcome of SNM compared to DO [13]. Therefore, we were very much interested in both urodynamic and clinical results for patients treated by ExMI. A significant number of pa- tients showed improvement of urodynamic variables in the present study. After ExMI treatment, a decrease in DO of 60% is seen. McFarlane et al. also report this observation; magnetic stimula- tion of S3 acutely abolished unstable contractions in patients with idiopathic DO [14]. Galloway et al. showed DO prior to treatment in 5 patients with stress incontinence, successfully treated with ExMI; at follow-up this observation was only present in 1 [6]. In the present study for URI the same finding occurred; the amplitude of urethral pressure changes decreased. Unlike our previous observations after SNM therapy were mainly major URI diminished after SNM therapy;

this was not true for the present ExMI study where a decrease in URI is mainly seen in minor URI.

One patient with no URI at baseline presented with major URI at follow-up; this observation is reported in previous studies comparing urodynamic data and raises the question of specificity and sensitivity of urodynamic testing [13].

Due to the small sample size, we did not discriminate for the various indications for therapy and urodynamic findings. The FSF, an important parameter for sensory symptoms increased by 47%.

Unfortunately this did not lead to an improvement in quality of life; the VAS did not show a clinical relevant change. Mean score on the VAS did even show a slight worsening in micturition related QoL Reason for this however is not understood and raises the question if the tools used are suitable for ExMI therapy evaluation.

The varying outcomes reported by several investigator groups raise the question if the finding of ExMI treatment is comparable. First of all different regimes are used to treat voiding dysfunctions by ExMI. The frequencies used vary between 10 and 50 Hz; 10 Hz is most effective in inducing bladder inhibition, and 50 Hz is most effective to increase maximum intra-urethral pressure in stress incontinence patients [5]. Secondly, the intensity of stimulation depend on tolerability as indicated by the patient; increasing the stimulus may lead to an unpleasant sensation in the lower abdomen. Stimulation at a lower level of the maximum might cause differences in outcome. The stimulus intensity was not taken into account in the present study, like in most reported studies on ExMI. Thirdly, male and female patients with different voiding (urge, stress and mixed incon- tinence, urgency/frequency), and faecal dysfunctions are treated by ExMI; the result may well be

‘contaminated’ outcome that make it almost impossible to draw conclusions. Better-standardised protocols are needed for evaluation of both therapy and urodynamics.

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Like other investigator groups, we report on short-term results after ExMI; long-term results are fairly unknown. Further long-term efficacy studies are needed for ExMI.

Conclusions

No clinical benefit for patients with stress, urge or mixed incontinence treated by ExMI was observed in our study group. Unfortunately, patients are few. Urodynamic evaluation revealed a significant improvement in parameters, related to voiding symptoms. This however does not lead to an improvement in micturition related QoL. Reason for this is not understood and makes it evident that further research for correlation of clinical success and urodynamic parameters is needed.

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