Model Number 302-20
Event Date 11/20/2007
Event Type Malfunction
It was reported to mfr that a sys diagnostic test performed on the vns pts device revealed high lead impedance with output status ok. A second system diagnostic test performed at the same office visit revealed high lead impedance with the out put status at the limit. The pt presented at the physicians office with continuous neck pain and extreme coughing during stimulation of the device, which began the previous day. The pt reported having had pulled his left neck muscle the day prior. Additionally, the physician stated that the pt is a truck driver and does "a lot of movement in his neck, so he may have stretched the leads". It was recommended to set the normal mode and magnet mode output current ot 0ma, however the physician opted to decrease the settings from 1ma to 0. 75ma decrease the pulse width from 500usec to 250usec. The coughing and the pain improved with the setting change. The pt was referred to the implanting surgeon to have the device replaced. Preoperative interrogation of the device revealed that at some point the device output current had been set to 0ma. During surgery, it was observed that the negative coil was a "burnt yellowish color" and that the "nerve was burnt at the site where the negative electrode was in contact with the nerve". The area above and below the burnt area on the nerve was swollen. The entire lead, including the electrodes was removed,and a new lead was implanted. The generator was replaced prophylactically. Additionally, the surgeon reported that the pt was experiencing hoarseness prior to the device being removed. Attempts to obtain the explanted devices for analysis have been made, but have been unsuccessful to date.
Device failure is suspected, but did not cause or contribute to a death.https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=2998029