Trial of Continuous Versus Cyclic Stimulation in Interstim Therapy

The components of SNS include a quadripolar lead wire that is placed adjacent to a sacral nerve root (typically S3), and an implantable pulse generator (IPG) that the lead wire is attached to. The IPG provides the electrical impulse and has several parameters that are amenable to adjustment including rate, strength and length of stimulation. Additionally, the stimulation can be programmed to be continuous or cyclic. If the therapy is equally efficacious at both settings, the cyclic setting has the advantage of resulting in a longer battery life. This would prolong the time interval between IPG replacements which would reduce the number of times a patient is exposed to a surgical procedure and may have a substantial impact on reducing cost to the healthcare system.

Participants will be randomized into one of two groups: either cyclic stimulation or continuous stimulation after IPG placement and will continue with this setting for four weeks. Subjects will return to the office 4 weeks post-op. They will complete a 3-day consecutive voiding diary just prior to their study visit. The subject will then undergo reprogramming to change the stimulation to the alternate pattern (from cyclic to continuous or vice versa as appropriate) keeping all other parameters the same. Subjects will be asked to return to the office 4 weeks after being switched to the alternate setting. She will complete a 3-day consecutive voiding diary just prior to the visit. The subject will also be asked their preference of mode of stimulation and the reason for their choice. After this visit, the participant will be switched to the mode of stimulation that is most efficacious for her.

Inclusion criteria

• You are eligible to participate in this study if you have the diagnosis of urge/frequency or urge incontinence and have undergone a successful Interstim trial and are planning on proceeding with IPG placement.
• All subjects must have had a minimum of a 50% improvement of one or more of the parameters being measured on the voiding diary to be considered a candidate for implant.
• Eligibility criteria also include non-pregnant women over the age of 18 who are able to provide informed consent and are willing to accept randomization.

Exclusion criteria

• You are not eligible to participate in this study if:

• you are under 18 years of age;
• pregnant or planning to become pregnant;
• have underlying neurological disease;
• stress incontinence;
• unable to read English;
• inability to complete the voiding diary; and
• inability to complete the follow-up visits.