Which describes 'lead impedance drift' in Axonics SNM systems?

• A. Sudden instantaneous change in impedance within minutes.
• B. No change in impedance over time.
• C. Random large fluctuations with no pattern.
• D. Gradual change in impedance over time indicating potential lead fatigue or tissue changes.

Answer: (D)

Lead impedance drift means a slow, progressive change in the measured impedance of the stimulation lead over time. This gradual trend reflects ongoing changes at the electrode–tissue interface and small mechanical factors, such as tissue encapsulation around the electrode or minor lead movement, rather than a sudden fault. That’s why describing it as a gradual change over time that can indicate evolving lead fatigue or tissue changes fits best. In contrast, an instantaneous jump points to a fault or transient issue, no change over time implies perfect stability, and large random fluctuations suggest noise or intermittent faults rather than a steady drift.