Biomechanical and functional variation in rat sciatic nerve following cuff electrode implantation.
BACKGROUND
Nerve cuff electrodes are commonly and successfully used for stimulating peripheral nerves. On the other hand, they occasionally induce functional and morphological changes following chronic implantation, for reasons not always clear. We hypothesize that restriction of nerve mobility due to cuff implantation may alter nerve conduction.


METHODS
We quantified acute changes in nerve-muscle electrophysiology, using electromyography, and nerve kinematics in anesthetized Sprague Dawley rat sciatic nerves during controlled hindlimb joint movement. We compared electrophysiological and biomechanical response in uncuffed nerves and those secured within a cuff electrode using analysis of variance (ANOVA) and regression analysis.


RESULTS
Tethering resulting from cuff implantation resulted in altered nerve strain and a complex biomechanical environment during joint movement. Coincident with biomechanical changes, electromyography revealed significantly increased variability in the response of conduction latency and amplitude in cuffed, but not free, nerves following joint movement.


CONCLUSIONS
Our findings emphasize the importance of the mechanical interface between peripheral nerves and their devices on neurophysiological performance. This work has implications for nerve device design, implantation, and prediction of long-term efficacy.
Stephen M
SM
Restaino
Erkinay
E
Abliz
Kelliann
K
Wachrathit
Victor
V
Krauthamer
Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA. sbshah@ucsd.edu.
Sameer B
SB
Shah
D000818:Animals; D001696:Biomechanical Phenomena; D004599:Electric Stimulation Therapy / Q000009:adverse effects* / Q000295:instrumentation*; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004576:Electromyography; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000502:physiology*