Sacral neuromodulation has been performed for more than 25 years. Lead migration and subsequent lead revision surgery are reported complications, yet little is known about the characteristics of lead migration and forces occurring during lead extraction. The aim of this study was to compare a novel finned stretchable braid reinforced lead to a tined lead in terms of lead extraction forces and extraction behavior in an acute animal model.

The study was performed using one acute sheep model under Institutional Animal Care and Use Committee (IACUC) #1727. Four (4) tined leads and four (4) finned leads  were implanted in the sheep sacrum under fluoroscopic control. Leads were then tunneled laterally to the typically expected location of an implantable pulse generator (IPG). Pulling of leads occurred from this position in order to simulate a lead pull form the IPG pocket site. [1]

A strain gauge (Shimpo FGV-20XY) with stepper motor were used to capture the force and distance recorded to a LabView Vi. Lead pulls were observed simultaneously during pulls via lateral fluoroscopy.

Lead breakage was observed in a tined lead at 14.12N.  This lead failed in a fashion that clinically would have left lead fragments in the body. This site was tested again with an additional tined and finned lead to evaluate the foramen further.

The second tined lead also mechanically separated upon extraction at a peak load of 13.49N.  The additional finned lead in this same location completely extracted without mechanical failure at a force of 19N, the highest observed by a finned lead. [2]

The stretchability of the finned lead may prevent displacement of the tines during traumatic events such as a fall, possibly reducing lead tip migration and loss of neuromodulation therapy in the clinical setting. The braid and fins design allowed the lead to be removed intact without leaving fragments behind in the animal model. The tined lead transferred pull forces more directly to the lead stimulation tip, which could result in migration clinically. Higher pull forces resulted in tined lead tip migration and caused the stimulation contacts to exit the sacral area, also resulting in lead fracture.

In the clinical setting, a sacral neuromodulation lead which is stretchable may have an advantage of reduced lead migration. A finned, stretchable braid enforced lead may reduce lead fracture and allow intact lead removal from the IPG pocket. Further investigation is needed to explore and define sacral lead migration from the distal and proximal lead end.


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The authors receive compensation for services to COMPANY NAME, which is developing products related to the research described in this paper.  Opinions and conclusions herein are solely those of the authors themselves. COMPANY NAME makes no claims regarding the opinions expressed herein.