Retrospective study of sacral neuromodulator implantations in a French hospital center: Lifespan and hospital costs assessment.

Purpose: Sacral nerve neuromodulation (SNM) is a safe and effective therapy for the management of fecal and/or urinary incontinence. The generators InterStim™ and InterStim™ II (Medtronic™) are non-rechargeable active implantable medical devices with a limited lifespan. The aims of this study were to assess the generators' median lifespan for all indications and the long-term hospital costs of the therapy.

Methods: This was a retrospective monocentric study that included 215 patients aged over 18 years who were treated by SNM for fecal incontinence and/or urinary incontinence. Lifespan was considered as the amount of time between definitive implantation and observed battery depletion by the surgeon and was assessed by the Kaplan-Meier method. Costs were assessed according to the activity-based pricing of the French public health care system.

Results: The median observed lifetime of stimulators implanted in our center was 7.29 years and 5.9 years for InterStim™ and InterStim™ II, respectively. The difference observed between the two generations was statistically significant. The modelling of primary implantation and renewal costs allowed us to observe that the decrease in the lifetime of Interstim™ II is associated with an increase in hospital costs over time. The retrospective study design is one limitation and we did not take into consideration stimulation's settings.

Conclusions: The InterStim™ II lifespan is shorter than the first-generation device. This is associated with an increase of the long-term hospital costs. Additional information about the new neuromodulator will be required to choose the most appropriate IPG for the patient while optimizing the costs.