Extracorporeal magnetic stimulation is of limited clinical benefit to women with idiopathic detrusor overactivity: a randomized sham controlled trial.

Objectives: To observe the effect of both acute and medium-term magnetic stimulation of the pelvic floor on detrusor function amongst women with idiopathic detrusor overactivity (IDO).

Methods: Two separate studies were undertaken amongst women with a sole diagnosis of IDO. The first study assessed the acute effect of magnetic stimulation (provided by Neocontrol ) on detrusor function during the filling phase of standard cystometry. Multiple filling cycles were performed with stimulation at a different key moment in each. This was done to establish that the device could influence the detrusor. Subsequently, a randomized sham control trial was performed to assess clinical efficacy. A total of 20 treatments, each of 20 minutes duration, were administered over six weeks with follow-up six weeks thereafter. Half the patients received therapy from a genuine device, the others receiving fake treatment on an identical looking/sounding sham device. The sham device contained a deflector plate to degrade the magnetic field and was located in a separate room. Outcome measures included changes in a 24 hour fluid volume chart, urine loss (24 hour pad test) and quality of life instruments.

Results: Amongst 10 patients receiving stimulation during cystometry, volume at first involuntary detrusor contraction during filling rose from a median value of 240ml (Inter-quartile range (IQR) 210-300) to 285ml (IQR 231-320), p = 0.03 and maximum detrusor pressure decreased from 40cm water (IQR 34-45) to 33cm water (IQR 25-41), p<0.01. The RCT was completed by 29 of 44 (66%) recruits. Of these, 15 of 29 (52%) received active treatment and 14 of 29 (48%) sham therapy. Active therapy significantly reduced the number of urge episodes per day, p<0.01. With respect to baseline, actively treated patients experienced significant reduction in voids per day and quality of life but this trend did not reach significance when compared to the sham group, partly due to unexpected difficulty in recruitment which yielded an underpowered sample size for these outcome measures.

Conclusions: Magnetic stimulation reduces detrusor contractility in the acute phase of administration. Although the treatment was well tolerated and urge episodes reduced following prolonged therapy, no statistically significant improvement was observed in quality of life indices or measured 24 hour urinary loss. The treatment cannot be recommended for women with IDO.