Is on-demand sacral neuromodulation in patients with OAB syndrome a feasible therapy regime?

INTRODUCTION: Sacral neuromodulation (SNM) of the lower urinary tract has proven to be safe and effective in patients with complaints of OAB syndrome who are not responding to conservative therapy. After 5 years of treatment the implanted system is still effective in 56-71% of patients. The loss of effect could be caused by adaptation of the nerve system to prolonged stimulation of the sacral nerves. MATERIALS AND METHODS: We set up a pilot intervention study. After a run-in period of 2 weeks patients were randomized into two groups: one group with on-demand neuromodulation (intervention group) and one group with continuous neuromodulation (control group). Patients in the intervention group were instructed to switch their INS off by default and to switch it on again when they felt recurrent symptoms, patients in the control group were asked to use their system as normally. RESULTS: After 2 weeks 10 out of 16 subjects reported a comparable symptom score during on-demand use of their neuromodulation system. Patients appreciated the comfort of being self-determent in the need for therapy. CONCLUSIONS: Possible benefits for patients could be: more autonomy, longer battery life of the implanted INS, decreasing the chance of adaptation by the nervous system.

Results of sacral neuromodulation therapy for urinary voiding dysfunction: outcomes of a prospective, worldwide clinical study.

PURPOSE: This 5-year, prospective, multicenter trial evaluated the long-term safety and efficacy of sacral neuromodulation in patients with refractory urge incontinence, urgency frequency and retention. MATERIALS AND METHODS: A total of 17 centers worldwide enrolled 163 patients (87% female). Following test stimulation 11 patients declined implantation and 152 underwent implantation using InterStim. Of those treated with implantation 96 (63.2%) had urge incontinence, 25 (16.4%) had urgency frequency and 31 (20.4%) had retention. Voiding diaries were collected annually for 5 years. Clinical success was defined as 50% or greater improvement from baseline in primary voiding diary variable(s). RESULTS: Data for all implanted cases were reported. For patients with urge incontinence mean leaking episodes per day decreased from 9.6 +/- 6.0 to 3.9 +/- 4.0 at 5 years. For patients with urgency frequency mean voids per day decreased from 19.3 +/- 7.0 to 14.8 +/- 7.6, and mean volume voided per void increased from 92.3 +/- 52.8 to 165.2 +/- 147.7 ml. For patients with retention the mean volume per catheterization decreased from 379.9 +/- 183.8 to 109.2 +/- 184.3 ml, and the mean number of catheterizations decreased from 5.3 +/- 2.8 to 1.9 +/- 2.8. All changes were statistically significant (p <0.001). No life threatening or irreversible adverse events occurred. In 102 patients 279 device or therapy related adverse events were observed. At 5 years after implantation 68% of patients with urge incontinence, 56% with urgency frequency and 71% with retention had successful outcomes. CONCLUSIONS: This long-term study demonstrates that InterStim therapy is safe and effective for restoring voiding in appropriately selected cases refractory to other forms of treatment.

Medium-term experience of sacral neuromodulation by tined lead implantation.

OBJECTIVE: To describe patient selection for sacral neuromodulation, also known as Interstim therapy, and the results of tined-lead implantation in the medium term. PATIENTS AND METHODS: In all, 49 patients, 39 with refractory overactive bladder symptoms and 10 with urinary retention, were implanted with the tined lead under local anaesthesia. The mean (sd) test period was 12.4 (5.8) days. Patients were implanted when they had a > or = 50% improvement in voiding diary variables during the test period. The mean follow-up for implanted patients was 15.5 (7.9) months. Changes in voiding variables were compared using a t-test. RESULTS: Ten patients had a one-stage and 39 a two-stage implant; of the latter group, 31 (80%) had a positive response and eight (21%) did not. In all, 31 patients were included in the follow-up. At the last follow-up, 28 (90%) patients had a >50% improvement in diary variables and three (10%) did not. In 21 patients with urgency symptoms the mean (sd) number of voids decreased from 11.7 (8.9)/day at baseline to 7.3 (3.4)/day (P = 0.1); the voided volume increased from 160.2 (70.7) mL to 231.1 (119.5) mL (P = 0.001); and the number of leakages decreased from 9.5 (8.7) to 3.3 (2.2)/day (P = 0.17). In the 10 patients with retention, the number of catheterizations decreased from 5.44 (1.6)/day with a volume of 297.6 (76.8) mL, to 1.2 (1.7)/day and 111.6 (158.1) mL; the mean number of voids increased from 3.7 (3.8)/day with a volume of 123.3 (141.7) mL, to 4.2 (2.4)/day and 248.3 (146.0)mL. There were no significant differences in the variables in the patients with retention. Seven patients had an adverse event. There was one incomplete electrode migration that was treated conservatively. CONCLUSION: This new minimally invasive approach gives positive results in the medium term. Two-stage testing with the tined lead seems more reliable than the classic percutaneous nerve evaluation. The lead anchoring method seems sufficient for fixing the electrode in the medium term.