Transcutaneous sacral electrical stimulation versus oxibutynin for the treatment of overactive bladder in children

Nowadays there is still no ideal treatment for paediatric overactive bladder. Initial management measures (urotherapy and constipation control), resolve 40% of cases. The second line of treatment in overactive bladder is anticholinergic drugs, above all oxybutynin. Although most patients improve with these therapies, the complete resolution rate is around 30-40%. Sacral transcutaneous electrical nerve stimulation has recently emerged as a new alternative in the management of patients with refractory paediatric overactive bladder. However, only a few studies have been done to compare the effectiveness of this therapy versus conventional drugs.

The objective of the present study is to compare, in children with overactive bladder, the efficacy of the sacral transcutaneous electrical nerve stimulation versus oxybutynin therapy.

We performed a prospective and randomized study of patients with diagnosis of overactive bladder treated with sacral transcutaneous electrical nerve stimulation versus oxybutynin, during the period July 2018-July 2020. Patients refractory to standard urotherapy and constipation management randomly received one of the therapeutic alternatives. Treatment was maintained for 6 months.

86 patients were included in the study: 40 patients received electrotherapy (group 1) and 46 patients received oxybutynin (group 2). Before starting the treatment assigned both groups were comparable related to the voiding symptomatology as well as the severity of the overactive bladder. Sacral transcutaneous electrical nerve stimulation was significantly more effective than oxybutynin, with a higher percentage of complete resolution of symptoms in the management of paediatric overactive bladder.

All the parameters obtained with the voiding calendar significantly improved in both groups at the end of the treatment. The increase in MaVV was significantly higher in group-1.

We observed a progressive decrease in the mean score obtained in the DVISS questionnaire over time in both groups. This decrease was significantly higher in group-1 compared to group-2 (p < 0.005). The mean value obtained in the DVISS questionnaire in group-1 was 6 (interquartile range: 3-9) at the end of the treatment (lower than the diagnostic cut-off point for daytime condition in the DVISS, 8.5). In group-2, the mean value obtained in the DVISS questionnaire was 10 (interquartile range: 8.75-13.25), higher than the cut-off point.

A greater number of adverse effects was obtained in group-2 (26.1% versus 15%, p < 0.05). Constipation (n: 6, 10.9%), and abdominal pain (n: 2,4.3%) were the most frequent adverse effects in this group. The adverse events reported in group-1 were contact dermatitis (n: 1.2%) and fecal losses [2] or urgency [5].

Oxybutynin and sacral transcutaneous electrical nerve stimulation are both effective therapies in the management of paediatric overactive bladder. However, electrotherapy has been shown to be a more effective therapy with a complete clinical resolution rate in a larger number of patients. Furthermore, the rate of adverse effects secondary to electrotherapy is significantly lower than those treated with oxybutynin.