Dual-mode apparatus and method for detection of embolic device detachment

摘要

An apparatus and method are disclosed for accurately detecting the detachment of both electrically conductive and non-conductive implants which have been introduced to and are intended to remain at a desired therapeutic site. The detachment detection apparatus may include a conductive or an electrically-isolated implant, such as a vasoocclusive coil, connected to a wire by an electrolytically severable joint. The detachment assembly further includes a power supply having a direct current drive circuit for supplying a direct current to the joint, an alternating current drive circuit for independently supplying an alternating current to the joint, and an alternating current monitoring circuit for monitoring an alternating current level of the alternating current supplied to the joint. The detection assembly includes a central processing unit for selecting a first mode and a second mode for determining a detachment threshold level indicating detachment of the implant. Additionally, a direct current monitoring circuit is provided for measuring a direct current impedance level of the direct current supplied to the joint wherein a percentage increase in the direct current impedance level indicates detachment of the implant if the alternating current level is greater than the detachment threshold level.