Pediatric lower urinary tract dysfunctions (LUTD) can be a result of overactive bladder (OAB), neurogenic lower urinary tract dysfunction (NGLUTD) or dysfunctional voiding. The prevalence of LUTD in children ranges widely from 1 to 20% resulting in a substantial economic and psychological burden to patients and their families. Neuromodulation could be of value in some patients in whom previous conservative and pharmacological therapies have failed. Various methods of neuromodulation have been studied. Since most of these techniques are invasive and involve implants, they are less utilized in children. Percutaneous (PTNS) or transcutaneous (TTNS) tibial nerve stimulation are techniques that are minimally invasive treatments for refractory lower urinary tract dysfunction with a response varying between 31–78%. In this review article we aim to study the efficacy, safety and tolerability of PTNS/TTNS in children.

To review the studies published from 2002 to 2023 and conduct a thorough search for relevant data from MEDLINE database using the following PICOs: pediatric PTNS, percutaneous neuromodulation in children, Percutaneous nerve stimulation, Peripheral nerve stimulation, Posterior tibial nerve stimulation. Twenty references were retrieved and found to be relevant to this current review.  Studies that focused on adults and NGLUTD were excluded.

A recent update in the guideline of the American Urological Association/Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction on adult with non-neurogenic OAB considered PTNS as a third-line management in a carefully selected patient. But, despite a growing body of evidence, neuromodulation in the pediatric population is currently used off-label. In 2015 two sham-controlled RCTs were published on the efficacy of TTNS in children with OAB, which eliminates the need for the percutaneous needle insertion, which is not painful but may be less tolerated in pediatric patients. Patidar et al reported a cure rate of 66.66% and an improvement rate of 23.81% in the TTNS group (n=21), compared to 6.2% and 12.5%, respectively, in the sham group (n=16). Boudaoud et al noted no difference in clinical result between TTNS and sham groups (n= 11 and 9), underlining the potential placebo effect. There is a lack of data on PTNS use in NGLUTS. Level 1 evidence exists supporting the efficacy of posterior tibial nerve stimulation (PTNS) in adult patients with non-neurogenic voiding dysfunction based on the SUmiT trial which demonstrated efficacy for this therapy in 220 non-neurogenic patients, with those in the PTNS arm exhibiting a 54.5 % response vs. 20.9 % for sham treatment. Capitanucci et al. in a study of 37 children noted that the non-NGLUTD responded much better than than neuropathic cases (78 versus 14%, p < 0.002) with cures in OAB and dysfunctional voiding (p < 0.01, but higher in the latter group). Treatment success was interpreted differently between studies. Some defined success by change in urodynamic parameters while others assessed symptoms. De Gennaro et al. evaluated percutaneous tibial nerve stimulation (PTNS) in 23 children with unresponsive lower urinary tract symptoms (LUTS) and showed normalization of cystometric bladder capacity in 62.5% with no more unstable contractions in those who became continent and an improved detrusor pressure at maximum flow (p=0.009). While, Hoebeke et al. prospective study on 32 patients with refractory LUTD showed a statistically significant increase in bladder capacity (p 0.001) from 185.16 to 279.19 ml, improvement in daytime frequency in 16 out of 19 (84%), urgency in 17 out of 28 (61%), and daytime incontinence in 16 out of 23 (70%). Ibrahim et al. study on 20 children with Refractory OAB underwent PTNS defined their subjective success as the patient request for continuing treatment. Sixty percent of patients had a better symptom and elected to continue the therapy to maintain the response, while 40% chose not to continue therapy because they did not have any symptomatic improvement. A highly significant difference between bladder capacities was observed and reported as 184.5±59.14 versus 259.5±77.22 before and after sessions, respectively (p=0.001).  De Gennaro et al. showed improvement in nocturnal enuresis in five out of eight patients, daytime frequency urgency in five out of 10 patients, and incontinence in five out of eight patients. Raheem used PTNS in primary resistant monosymptomatic nocturnal enuresis and reported symptomatic and urodynamic improvement of 78.6% in PTNS group (n=11) versus 14.3% in the control group (n=2). However, by follow up evaluation 3 months after the last session, the PTNS group improvement rate had fallen to 42.9%. Van der Pal also reported that 7 of 11 patients with an initially good response had evidence of subjective and objective deterioration after PTNS. This noted deterioration with time in some responders suggests the need for maintenance protocols. Capitanucci et al. also reported that repeating PTNS cycles and eventually using chronic monthly stimulation are necessary to maintain results. Protocol of the number of sessions also varied between studies. Mostly used weekly PTNS for 12 weeks that lasts for 30 min in each session. While Van der Pal participants received PTNS three times a week for 4 weeks. Combination with anticholinergic has also been explored through a randomized study by Souto et al. which showed a comparable efficacy among oxybutynin ER (extended release) 10 mg/day and PTNS +/- oxybutynin ER 10mg/day at 12 weeks. No serious side effects of PTNS in children were observed in studies. Peter, et al. a multicenter, randomized trial demonstrates a significant improvement in OAB patients receiving PTNS with comparable effects produced by extended-release tolterodine (79.5% reporting cure or improvement vs. 54.8%, p = 0.01). Capitanucci et al. reported no significant side effect, good tolerability of PTNS in children using pain scales down to four years of age. Hoebeke et al, reported that only one of 32 children discontinued treatment because of needle fear. Van der Pal reported some bleeding, pain at insertion site and numbness sole of foot. De Gennaro et al. evaluated pain tolerability using certain scoring systems and concluded that PTNS is safe, minimally painful and feasible in children. Recently, De Wall et al a single-center retrospective chart analysis on all children underwent PTNS in a group setting with their parents between 2016–2021. Study showed that facilitating PTNS in a group setting led to a better children’s coping in this stressful situation with an overall improvement of 42%.

Percutaneous tibial nerve stimulation is reliable and effective for refractory lower urinary tract dysfunction in children. Statistically significant improvement was noted in the Lower urinary tract symptoms and in urodynamic parameters by increase in cytometric bladder capacity, reduction of unstable contractions and improvement of detrusor pressure. There is no generally accepted regime for this intervention. Protocol of the pulse duration, stimulation frequency, and number and duration of stimulation sessions differed among studies. But, mostly widely used protocol is weekly PTNS for 12 weeks that lasts for 30 min in each session. The necessity of maintenance therapy due to the deterioration noticed in successfully treated patients. PTNS is safe, minimally painful and feasible in children. However, the time-consuming weekly in- office visits and the percutaneous approach make therapy child-unfriendly.

Despite the diversity of the methodology and outcome measurements among the studies they demonstrate that PTNS is safe and well tolerated to children that had failed previous standard treatments for overactive bladder with minimal side effects. Therefore, new techniques with implants are being explored and show initially promising results.

Continence 7S1 (2023) 100781
DOI: 10.1016/j.cont.2023.100781