Hypothesis / aims of study
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.
Study design, materials and methods
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.
Interpretation of results
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.