Sacral neuromodulation (SNM) is a well-established treatment for non-obstructive urinary retention (NOUR) in women. Axonics® launched the first rechargeable SNM device, which has a six-month battery life per charge, in 2019. We aim to evaluate the effectiveness of the Axonics Rechargeable SNM in the treatment of NOUR in women.

This is a prospective, single-centre case series including women over age 18 with a diagnosis of complete or partial NOUR deemed eligible for SNM therapy after discussion in a multidisciplinary functional urology meeting. Patients were enrolled between May 2019 and March 2023. Baseline demographics, symptoms and urodynamic parameters were recorded for descriptive analysis. 

All cases were performed as staged procedures starting with an advanced evaluation with a tined lead. Success was defined as >50% reduction in need for catheterisation, >50% reduction in post void residual and/or >50% improvement of their baseline lower urinary tract symptoms. Successful cases had the implantation of the neurostimulator during the second stage and were followed up at 3, 6, 12 months and then yearly as part of routine care. Patients who failed to respond to SNM underwent explantation of all components during the second stage.

A total of 12 female patients were prospectively included in this study, with a median age of 26 (range 19-47) at the time of surgery. Seven patients (58.3%) were catheter dependent (6 performing intermittent self-catheterisation and 1 with an indwelling catheter). Preoperative symptoms and urodynamic parameters are summarised in Table 1 and 2, respectively. 

Ten out of 12 (83.3%) patients had a successful advanced sacral neuromodulation evaluation using a permanent tined lead. The median length of the evaluation period was 28 days (range 14-42). Of the two failures, one patient still proceeded to a second stage (implant) due to benefits in bowel function but remained with an indwelling urethral catheter. The other one went ahead with removal of the tined lead. 

Four patients became catheter free after the trial. Two patients reduced their catheterisation rate by 50%. The remaining four patients with successful trials all improved by >50% their baseline symptoms. Six out of 10 patients (60%) suffered return of symptoms (ROS), with a median time of 15 months (range 0-63). One of them went ahead with a new trial which was successful, and patient continues to benefit from the therapy after 48 months. Of the five remaining patients who experienced ROS, two had to switch off the device due to leg pain, one switched it off during pregnancy and did not restore benefits upon reactivation after delivery, one had significantly gained weight (20 kg), and one suffered recurrent UTIs obscuring the benefits from SNM therapy.

Four patients (40%) continue to benefit from the therapy, with a median follow-up of 48 months (range 26-75).

Axonics Rechargeable SNS achieved 80% initial efficacy in treating women with NOUR, and the benefit is sustained at least 40% of patients in the medium term. The main limitation of our study is the small sample size. A larger comparison study among rechargeable devices is required.

Our preliminary results suggest that SNM therapy using the Axonics Rechargeable System is an effective treatment for NOUR in women with over 80% initial efficacy, offering sustained benefit in at least 40% of patients in the medium term.