An implantable lead is provided with at least one extendable member to
position therapy delivery elements, which may be electrodes or drug
delivery ports, after the lead has been inserted into the body. The lead
may formed as a resilient element which is contained in a retainer tube
that may be removed to permit the lead to deploy. Alternatively, a
non-resilient lead may be provided with a slotted retainer tube. A series
of mechanical linkages for expanding and retracting the lead within the
human body may be actuated with various mechanisms. A control system may
be provided for closed-loop feedback control of the position of the
extendable members. The invention also includes a method for expanding an
implantable lead in situ.
