[Study of the efficacy and medium-term complications of 41 sacral nerve neurostimulators (Interstim, Medtronic, U.S.A.) in refractory urinary disorders].

Objective: Single-centre retrospective follow-up study (short-term and medium-term efficacy, complications, revisions) of patients treated for refractory urinary disorders by sacral nerve neurostimulation (Interstim, Medtronic, U.S.A.).

Material And Method: A sacral nerve neurostimulation screening test was performed in 79 patients with refractory urinary disorders between 1999 and 2005 and a neurostimulator was implanted in 41 of these patients. Patients were evaluated by bladder diary, MHU urinary disability score, and urodynamic assessment.

Results: The mean follow-up was 20.5 months. A significant improvement of bladder diary parameters and MHU urinary disability score was observed at 6, 12, and 24 months of follow-up. At 20.5 months, 22 (54%) patients were considered to be failures and 3 were explanted. Five patients were considered to be a success, and 14 were improved, i.e. 19 (46%) success/improvement at 20.5 months of follow-up. The only predictive factor of success was a history of symptoms lasting less than 5 years before neurostimulator implantation. A complication was observed in 70% of patients. More than one half of patients reported pain at some time during follow-up. Four infections were observed, one of which required explantation. Ten technical problems due to accidental deactivation or interference with a magnetic field were observed. Seven patients (17%) required revision: repositioning of the leads due to inefficacy in 3 cases, and change of position of the device in 4 cases.

Conclusion: Sacral nerve neurostimulation is an effective treatment in refractory urinary disorders in more than 45% of implanted patients, although this effect tends to wane over time. Our results are less favourable than those described in the literature, but were based on stricter endpoints. A high complication rate, mainly pain, was observed, but most required only symptomatic management. This technique nevertheless remains a good alternative to invasive surgical management of functional disorders.