Electromechanical reshaping of septal cartilage.
OBJECTIVE
This study describes the process of tissue electroforming and how shape changes in cartilage can be produced by the application of direct current (DC). The dependence of shape change on voltage and application time is explored.


METHODS
Basic investigation using ex vivo porcine septal cartilage grafts and electromechanical cartilage deformation focused on development of a new surgical technique.


METHODS
Uniform flat porcine nasal septal cartilage specimens were mechanically deformed between two semicircular aluminum electrodes. DC current was applied to establish charge separation and electrical streaming potential. Voltage (0-3.5 V) and application time (0-5 minutes) were varied. Shape change was measured, and shape retention was calculated using analytic representation. The effect of the direction of applied current on shape change was evaluated by switching the polarities of electrodes and using parameters of 0 to 5.5 V and 5 minutes. Temperature during reshaping was monitored with a thermocouple, and surface features were evaluated using light microscopy.


RESULTS
Reshaped specimen demonstrated mechanical stability similar to native cartilage tissue. Shape retention strongly correlated with increasing voltage and application time. Only a small current (<0.1 A) through the tissue was measured. Temperature change was less than 2 degrees C during electroforming, suggesting that electroforming likely results from some nonthermal mechanisms. Surface features indicated that electrodeposition may occur depending on electrode material and magnitude of the applied voltage.


CONCLUSIONS
These findings demonstrate that cartilage can be reshaped through the process we have described as "electroforming" by generating intrinsic differences in charge separation with negligible heat production.
Ho
Ki-Hong Kevin
KH
Beckman Laser Institute and Medical Clinic, Department of Biomedical Engineering, University of California, Irvine 92612, USA.
Diaz Valdes
Sergio H
SH
Protsenko
Dmitriy E
DE
Aguilar
Guillermo
G
Wong
Brian J F
BJ
D000818:Animals; D001696:Biomechanical Phenomena; D046508:Culture Techniques; D004558:Electric Stimulation / Q000295:instrumentation; D009300:Nasal Septum / Q000601:surgery*; D013552:Swine; D013696:Temperature