MAUDE Adverse Event Report: CYBERONICS - HOUSTON PULSE GEN MODEL 105; GENERATOR

Model Number 105

Device Problem Energy Output Problem (1431)

Patient Problems Scarring (2061); Seizures (2063)

Event Date 12/13/2018

Event Type  malfunction  

Event Description

It was reported that the patient presented to the clinic due to an increase in seizures, which were attributed to the vns not being set to the settings of the previously implanted device.However, when the physician attempted to increase the settings to 2.50 ma, it was stated that a low output current warning was observed whenever normal and magnet mode were above 2.00 ma.The system and magnet diagnostics showed that impedances were within normal limits and the battery status indicator indicated that 75-100% of the battery capacity was remaining.The surgeon's, physician's, and company representative's tablet data were received and the patient's programming and diagnostics history was reviewed by the manufacturer.While the surgeon also reported a low output current on the date of implantation, an ohm's law calculation verified that it was expected that the device would not be able to deliver that programmed output current with the given lead impedance and normal device variation in impedance accuracy and maximum output voltage.However, at the follow up appointments, when the vns generator was unable to provide the programmed output current.After applying ohms law, it was expected that the device would be able to deliver that programmed output current with the given lead impedance and normal device variation in impedance accuracy and maximum output voltage.A review of device history records revealed that the generator passed quality control inspection prior to distribution.No additional relevant information has been received to date.

Event Description

The explanted products were received by the manufacturer.Lead product analysis was completed.The condition of the returned lead portions was consistent with those typically existing following explant.No obvious anomalies were identified beyond the setscrew marks near the end of the lead connector pin indicating that the lead had not been fully inserted in the generator cavity at one point.However, additional setscrew marks found on the pin provide evidence that a good mechanical and electrical connection was present at one point.No discontinuities were identified during continuity testing.There was no evidence to suggest an anomaly with the return portions of the lead.The generator is still pending product analysis.

Event Description

Further review of the data revealed that, while the low output current with the smaller pulse widths were an expected event due to ohm's law calculations and not considered a device failure, the even lower output currents observed with larger pulse widths were not an expected event.This was determined to be the result of the impedance measurement performed by the generator.Essentially, a longer pulse width can result in a higher effective impedance compared to the measured impedance, resulting in diagnostic information indicating that the output current is not being delivered when it actually is being delivered.However, as previously mentioned, due to the programmed settings and the impedance values of the device, the generator was still likely unable to provide an output current higher than those noted during the diagnostic testing with the smaller pulse width.

Event Description

The patient was referred for vns generator replacement surgery.Follow up with the surgeon revealed that the previous (prior to the current) generator was able to deliver a higher output current even with a higher impedance value.Review of the manufacturer's database confirmed that this was correct.During the replacement surgery, it was reported that the patient's new vns generator was tested outside of the patient at the desired settings with a test resistor.A low output current warning was observed at that time, which was expected as the test resistor impedance value was higher than the patient's current vns lead impedance.The patient underwent a full vns replacement surgery and it was stated that a neuroma had built up under where the vns electrodes were sitting on the nerve.After the surgeon implanted the new vns lead in a new location, the device was able to deliver the desired high output current.The explanted products have not been received by the manufacturer to date.

Event Description

Product analysis was completed on the patient's explanted generator.Proper functionality of the generator in its ability to deliver programmed output currents was successfully verified in the product analysis, or pa, lab.The low output current allegation was not duplicated in the pa lab.The generator was placed in a simulated body temperature environment and monitored for more than 24 hours.No variation in the output signal was observed and the diagnostics were as expected.The generator performed according to functional specifications.There were no performance or other adverse conditions found with the generator.

• Brand Name: PULSE GEN MODEL 105
• Type of Device: GENERATOR
• Manufacturer (Section D): CYBERONICS - HOUSTON; 100 cyberonics blvd; houston TX 77058
• Manufacturer (Section G): CYBERONICS - HOUSTON; 100 cyberonics blvd; suite 600; houston TX 77058
• Manufacturer Contact: njemile crawley ; 100 cyberonics blvd; suite 600; houston, TX 77058 ; 2812287200
• MDR Report Key: 8228780
• MDR Text Key: 132497383
• Report Number: 1644487-2019-00032
• Device Sequence Number: 1
• Product Code: LYJ
• UDI-Device Identifier: 05425025750054
• UDI-Public: 05425025750054
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: P970003
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,health
• Reporter Occupation: Physician
• Type of Report: Initial,Followup,Followup,Followup,Followup
• Report Date: 04/25/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 01/08/2019
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Lay User/Patient
• Device Expiration Date: 07/12/2019
• Device Model Number: 105
• Device Lot Number: 204193
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 03/28/2019
• Is the Reporter a Health Professional?: Yes
• Event Location: Other
• Date Manufacturer Received: 04/23/2019
• Was Device Evaluated by Manufacturer?: No
• Date Device Manufactured: 08/04/2017
• Is the Device Single Use?: Yes
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Initial
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 22 YR