Evaluation of clinical performance and safety for the rechargeable InterStim Micro device in overactive bladder subjects: 6-month results from the global postmarket ELITE study.

AIMS: Sacral neuromodulation (SNM) is an advanced therapy option for the treatment of overactive bladder (OAB), nonobstructive urinary retention, and fecal incontinence. The aim of this ongoing prospective, multicenter, global, postmarket study is to confirm safety and clinical performance of the InterStimTM Micro system for SNM in all indications. Reported here are the results for the OAB cohort through 6-month follow-up. METHODS: Eligible OAB subjects that had a successful therapy evaluation were enrolled after implant of an InterStim Micro implantable pulse generator (IPG). Subjects completed voiding diaries and the Overactive Bladder Quality of Life questionnaire (OAB-q) at baseline and follow-up visits occurring at 3 months and 6 months postimplant. Safety was evaluated as device-, procedure-, or therapy-related adverse events. The primary objective for the OAB cohort was to demonstrate an improvement in OAB-q Health Related Quality of Life (HRQL) total score at 3 months postimplant compared to baseline. RESULTS: Sixty-eight OAB subjects were enrolled and implanted with an InterStim Micro IPG. Of those, 67 and 66 subjects completed the 3- and 6-month follow-up visits, respectively. The OAB-q HRQL demonstrated a statistically significant improvement from baseline to 3-month follow-up with an average increase of 33 ± 24 points (n = 67, p < 0.001). The change was also observed at 6-months with an average increase of 31 ± 23 points (n = 65) compared to baseline. Eighty-two percent of subjects achieved the minimally important difference in HRQL score at 3- and 6-month, respectively, with a change of 10 points or greater. The majority of subjects reported that their bladder condition was better at 3-month (92.5%, 62/67) and 6-month (89%, 59/66) compared to before they were treated with SNM therapy delivered by the InterStim Micro system. For subjects with urgency urinary incontinence (UUI), the average change from baseline to follow-up in UUI episodes/day was -3.6 (95% CI: -4.7, -2.6; n = 62) at 3-month and -3.7 (95% CI: -4.7, -2.7; n = 61) at 6-month. Among subjects with urgency-frequency (UF), the average change from baseline to follow up in voids/day was -4.5 (95% CI: -6.3, -2.7; n = 52) at 3-months and -4.4 (95% CI: -6.0, -2.7; n = 52) at 6-month. The cumulative incidence of device-, procedure-, or therapy- related adverse events was 7.4% (5/68). Out of these five related adverse events, there was one serious adverse event (1.5%, implant site pain) at the time of database snapshot. CONCLUSIONS: These data confirm the safety and clinical performance of the InterStim Micro device for subjects with OAB by demonstrating a significant improvement in OAB-q HRQL score at 3-month. Similar improvements were observed at 6 months in addition to an incidence of adverse events that is comparable to previously reported rates for SNM.

Prospective, multicenter study to evaluate performance and safety of a re-engineered temporary lead for InterStim™ therapy evaluation.

AIMS: The basic evaluation or percutaneous nerve evaluation (PNE) is a method to assess pre-implantation therapeutic response in patients considering sacral neuromodulation for the treatment of refractory overactive bladder. A new PNE lead with a more robust design and greater distensibility designed to reduce the possibility of lead migration has recently been introduced to the market. The aim of this prospective, multicenter, global, postmarket study was to evaluate the clinical performance and safety of the new InterStim PNE lead with the foramen needle. METHODS: Patients with overactive bladder were enrolled in this study. The primary objective of this study was to determine the proportion of subjects who demonstrated motor or sensory response(s) during lead placement using the InterStim PNE lead. Additional measures included the Patient Global Impression of Improvement (PGI-I), patient satisfaction at the end of therapy evaluation, and change in bladder symptoms from baseline to the end of therapy evaluation (1-week follow-up visit). RESULTS: One-hundred and ten subjects met the inclusion and exclusion criteria and underwent a lead implant procedure. Of those, 108 had a successful procedure and 107 completed the 1-week follow-up visit. Ninety-nine percent of subjects (109/110) had a motor or sensory response during needle placement (95% confidence interval [CI]: 95%-100%) and 97% of subjects (107/110) had a motor or sensory response during lead placement (95% CI: 92%-99%). The majority of subjects (88%, 95/108) reported their bladder condition was better at the follow-up visit compared to before the PNE implant procedure, as reported in PGI-I. Subjects reported being satisfied with how the therapy impacted their voiding symptoms (82%, 88/108) and that they would recommend this therapy (87%, 94/108) to other patients. Symptom improvement was demonstrated with urinary urge incontinence subjects having an average of 4.2 ± 3.4 urinary incontinence episodes/day at baseline and 2.2 ± 2.5 at follow-up, and urinary frequency subjects having an average of 12.5 ± 4.4 voids/day at baseline and 10.5 ± 4.3 voids/day at follow-up. Lead removal was deemed to be easy and safe by the implanting physician, with a total of three adverse device effects in 3/110 subjects. No event was categorized as serious and all were resolved without sequelae. CONCLUSIONS: The updated InterStim PNE lead with a more robust design and greater distensibility designed to reduce migration was shown to have a high rate of motor or sensory response during lead placement. Furthermore, subjects reported high rates of global improvements and amelioration of symptoms, and the lead was easy to remove with minimal morbidity.