Additional method code: follow up info regarding this pt, who resides and was implanted outside of the usa, was requested but was not made available.
This is the final report.
Clinical summary: mother of 4 year-old boy reported on 28 november 1998 that her son was not reacting to sound anymore since he hit his head on the implant side that day.
This had also caused a little non-bleeding injury - a blue spot on the skin covering the implant was still visible 4 days after the incident.
Integrity test by cochlear staff on 2 december 1998 confirmed device failure - no output.
Visual inspection: the stiffening ring s3 and the electrode ring e17 was observed to br crushed.
The ball electrode was observed to be severed in two locations and had a number of bends.
The electrode array was observed to be severed between the helix and the stiffening rings.
The electrode array was observed to be kinked between the helix and the stiffening rings.
The silicone covering the electrode array was observed to have a cut between th helix and the stiffening rings, exposing electrode wires.
The stimulator case was observed to be dented on both the plate electrode and the logso sides.
The silicone covering the stimulator body was observed to have a tear and a cut.
X-ray of the unit revealed a crack on the ceramic hybrid circuit.
The crack on the ceramic hybrid circuit was confirmed visually after opening the titanium case of the unit.
Electrical tests: the unit failed the telemetry response test.
The unit failed the reflected impedance test.
Conclusion: the implant failed due to a cracked hybrid integrated circuit.
Electrode damage were observed.
It cannot be ruled out that the damages to the electrodes occurred during explantation as the investigation, including clincial evidence, did not yield any other probable cause.
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