Rechargeable batteries help reduce the overall size of implantable neurostimulators. Approved rechargeable devices weigh only 1 oz and are 10-mm thick.

Inductive Flex-Coils facilitate recharging, communications telemetry and are less vulnerable to breakage than discrete coils. Flex-Coils minimize the amount of space that must be allocated to battery and can extend the device life to about 10 years before replacement surgery is required. Without rechargeability, higher-power pain management devices must be much larger and batteries would require surgical replacement in 2–5 years. Rechargeable battery designs are now practical using inductive Flex Coils manufactured by Minco (www.minco.com).

Multilayer flexible circuits can fold in 3-D configurations and enable miniaturization of the implant’s motherboards. Rigid-flex circuits allow mother and daughter circuits to combine with electromechanical devices without connectors. Eliminating connectors not only frees up space in neurostimulators, it cuts costs.