Percutaneous tibial nerve stimulation (PTNS) is an alternative therapy for refractory overactive bladder. The need for maintenance therapy to sustain positive clinical results has been proposed in some papers, as well as logistics issues [1] At present, there is no standardized treatment regimen[2]. We describe the long term follow up of a cohort of patients with refractory OAB after first PTNS treatment, and offering one re-tretament cycle before manteinance therapy.

It is a  longitudinal study of a  cohort in a tertiary-level teaching hospital where adult patients underwent PTNS treatment for refractory OAB. All patients were treated with a course of 12 weekly 30-min sessions. The PTNS technique was performed using a low-voltage electrical stimulator and a 34-gauge acupuncture needle, following a standard protocol (210 µseg, 20 Hz, and maximum amplitude bellow pain or discomfort level). 
The assessments performed were: OABq-SF questionnaire, bladder diary of 3 days (Spanish version) and Treatment Benefit Scale (TBS) questionnaire. The evaluation were performed one week before the treatment and one month after PTNS treatment finished. Patients contacted the department when they experienced recurrence of OAB symptoms, then  they were offered for a re-treatment of 6 weekly 30 minutes sessions, or Botulinum toxin or Sacral neuromodulation or Standard of care (SOC). If patients experienced recurrence of symptoms again, they were offered maintenance therapy, PTNS 30 minutes session every one month, or Botulinum toxin or Sacral neuromodulation or SOC. Follow-up was done at the outpatient clinic, and the global clinical response was evaluated according to TBS.

In our study 58 patients were evaluated, with mean (SD) age was 56,7 (14,7) years, and 47 (81%) were female.  The  median follow-up was 46 months. TBS was greatly improved in four (6,9%), improved in forty-two (72,4%) and not changed in twelve patients (20,7%). Variables that experienced an statistically significant improvement were OABq-SF, episodes of urgency, voids in 24 hours, nightly void and episodes of incontinence (Table 1).
46 patients (79,3%) experienced improvement of symptoms. 34 patients with successful treatment experienced relapse of symptoms and received re-treatment (6 weekly 30-min sessions), the median (IQR) for the relapse of symptoms were 8,5 (8-14) months.  After re-treatment, twenty-four patients asked for maintenance and six patients didn´t stay in maintenance. During maintenance 4 patients have lost efficacy. Of the 46 patients with successful treatment, 12 didn´t receive re-treatment and 7 remain asymptomatic with a median (IQR) of 44 (32,8-55,8) months.
Therefore 11 patients of 46 with improvement of symptoms, that represented 23,9%, were asymptomatic without need for maintenance and with a median follow-up of 46 months. Figure 1

This study showed a subjective success in 79,3%, and objective success according to the bladder diary, after 12-week PTNS. Patients did not experience significant side effects, similar to findings from previous studies demonstrating safety and efficacy of PTNS for the management of OAB. Panicker et al [3] showed that patients with successful PTNS that did not return to maintenance  had higher perception of satisfaction than group that returned to maintenance. They suggested a mismatch between improvements in objective measures and subjective measures. The question is that the option to return to maintenance depends on subjective evaluation. We propose the idea of administering re-treatment of 30 minutes sessions over 6 weeks, when patient complaint of relapse of symptoms, before to decide maintenance, according to subjective perception on TBS. Patients that did not return to maintenance were comfortable with symptoms, with a median follow-up of 44 months. With this strategy, we have been able to avoid maintenance in 19% of patients.

In our experience, some patients (up to 19%) may benefit from a more conservative strategy, offering observation and re-treatment cycle after relapse of symptoms before starting  maintenance therapy.

F. Van Der Pal, M. R. Van Balken, J. P. F. A. Heesakkers, F. M. J. Debruyne, and B. L. H. Bemelmans, “Percutaneous tibial nerve stimulation in the treatment of refractory overactive bladder syndrome: Is maintenance treatment necessary?,” BJU Int., vol. 97, no. 3, pp. 547–550, 2006.
L. L. de Wall and J. P. F. A. Heesakkers, “Effectiveness of percutaneous tibial nerve stimulation in the treatment of overactive bladder syndrome,” Res. Reports Urol., vol. 9, pp. 145–157, 2017.
J. N. Panicker et al., “Factors influencing return for maintenance treatment with percutaneous tibial nerve stimulation for the management of the overactive bladder,” BJU Int., pp. 0–3, 2018.