Objective: The aim of this study was to evaluate in a prospective, randomized setting if the 2-stage implant, compared to a 1-stage implant, leads to a superior subjective or objective outcome of sacral nerve stimulation after implantation of the pulse generator in patients with lower urinary tract symptoms.
Patients and methods: We implanted a sacral (S3) foramen lead and a pulse generator (model 3023, Medtronic Inc, Minneapolis, MN, USA) in 42 patients. They were randomized in a 1-stage or a 2-stage implant if a more than 50% improvement in voided volume or reduction of residual urine was seen during the test stimulation phase as compared to baseline.
Results: At 24 months follow-up, subjective (visual analogue scale) and objective (voided volume or residual urine) assessment were significantly better in the 2-stage group. Ten patients (24%) failed therapy, 7 in the 1-stage implant and 3 in the 2-stage group. Two patients were lost to follow-up. Logistic regression analysis revealed that failure was positively related to the 1-stage implant and negatively to the age of the patients. 76% of the treated patients had sustained clinical benefit with 23 revisions performed. The mean cost is respectively for the PNE (2006 Euro), for the 2-stage implant (10826 Euro) and for the 1 stage implant (8505 Euro).
Conclusion: With this study, we demonstrated that the 2-stage implantation technique of the sacral neuromodulation therapy performed as a longer test stimulation phase has a higher success rate.