Biomechanical strength of reconstruction plates when used for medial support of MED-El cochlear implants: implications for diagnostic MRI.
OBJECTIVE
It is hypothesized that a mesh reconstruction plate designed to fit a cochlear implant (CI) internal device will provide immediate structural support to the site of the implant and that this strength far exceeds the forces induced by a 1.5-tesla MRI.


METHODS
Human calvarial specimens were drilled and plated with reconstruction mesh. Force was applied until failure was reached.


RESULTS
Mean maximum force, mean force to first failure and mean displacement measures for group 1 (resorbable mesh, n = 10) were 302.9 N, 283.0 N and 3.05 mm, respectively. The mean maximum force for group 2 (0.4-mm titanium mesh, n = 10) and group 3 (0.6-mm titanium mesh, n = 8), were 121.3 and 234.0 N, respectively. Mean force of first failure was 92.0 N for group 2 and 164.8 N for group 3.


CONCLUSIONS
The force required for failure of the mesh is significantly greater than the 0.17 N exerted on a CI magnet by a 1.5-tesla MRI scan.
Poetker
David M
DM
Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Wackym
P Ashley
PA
Yoganandan
Narayan
N
Runge-Samuelson
Christina L
CL
Firszt
Jill B
JB
Pintar
Frank A
FA
D020341:Absorbable Implants; D001696:Biomechanical Phenomena; D001860:Bone Plates; D002102:Cadaver; D003054:Cochlear Implants; D000075202:Contraindications; D004867:Equipment Design; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects; D012886:Skull / Q000502:physiology* / Q000601:surgery; D013314:Stress, Mechanical; D014025:Titanium
D014025:Titanium