Study design, materials and methods
Five (5) standard tined leads
Five (5) novel finned leads
EQUIPMENT
Instron Test System: ISN 01538 with testing software and accessories
Testing Procedure:
Three tests were conducted:
- Cyclic Elongation testing: Test samples were engaged in the Instron tester and pulled to defined elongation values of 1,2,3,4,5,10,5,20,30,40,45 mm, respectively. Samples were returned to initial start point between each cycle of elongation. (see Figure 1)
- Anchor (fixation) Failure testing: Fixation features were constrained in a silicone tube filled with silastic adhesive. Testing was performed by pulling on the fixation area of each lead and the connector end.
- Mechanical Failure testing: Leads were tested for lead body strength from the lead connector end to a point between the fixation feature and the most proximal electrode. Force at mechanical failure was recorded. (See Figure 2)
Interpretation of results
As compared to the tined lead the stretching quality may reduce force transmitted to the lead tip thus requiring higher forces prior to lead migration in the finned design. The finned sacral lead compensates for force on the lead by temporarily stretching.
Force required for anchor failure is similar for both leads however permanent lead deformation is more likely in the tined leads.
The force needed to induce mechanical failure of the tined leads was significantly lower than that of the finned leads.