NOVEL TEST LEAD DESIGNS FOR SACRAL NERVE STIMULATION: IMPROVED PASSIVE FIXATION IN AN ANIMAL MODEL

Abstract

To evaluate the ability of two novel coiled test stimulation lead designs to reduce or eliminate undesired migration and concomitant loss or attenuation of responsiveness to sacral nerve stimulation (SNS) associated with standard percutaneous nerve evaluation (PNE) leads. The two novel leads (Coiled Leads 1 and 2) and a standard PNE lead were inserted bilaterally in sacral foramina of female goats. At various times thereafter threshold voltage responses were measured. Prior to lead removal, distance of lead migration was evaluated by x-ray imaging and the force necessary to displace the leads measured. Thereafter, as the leads were being removed, the force necessary for removal was also measured. Migration was consistently either nil or minimal for both coiled leads. In contrast, migration of the standard lead occurred in all cases and was substantial in magnitude. A significant linear association was evident between the migration distance of the standard lead and the corresponding voltages needed to evoke a response. The forces necessary to displace Coiled Lead 1 and Coiled Lead 2 were both significantly higher (p <0.01) than those for the standard lead. In some cases comparatively high forces were needed for removal of Coiled Lead 1 but not Coiled Lead 2. Coiled lead designs appear to offer a potentially promising alternative to standard leads for PNE, allowing a wider range of patients to be correctly identified as candidates for sacral root neuromodulation. Coiled Lead 2 merits further investigation in human subjects.