Abstract: Effect of Polymerization Methods on Peripheral Nerve Regeneration (Plastic Surgery 2011 (September 23-27, 2011))

Sunday, September 25, 2011: 11:05 AM

Colorado Convention Center

Ziya Baghmanli, MD , Surgery/Plastic Surgery, University of Michigan, Ann Arbor, MI

Melanie Urbanchek, PhD , Surgery/Plastic Surgery, University of Michigan, MI

Benjamin Wei, MD , Surgery/Plastic Surgery, University of Michigan, Ann Arbor, MI

Bong Shim, PhD , Material Science, University of Delaware, Newark, DE

Kristoffer Sugg, MD , Surgery/Plastic Surgery, University of Michigan, Ann Arbor, MI

David Martin, PhD , Material Science, University of Delaware, Newark, DE

William Kuzon, Jr, MD, PhD , Plastic Surgery, University of Michigan, Ann Arbor, MI

Paul Cederna, MD , Ann Arbor, MI

Presentation PDF file

Objective: 3,4 polyethylenedioxythiphene (PEDOT) is a conductive polymer being tested for neural-machine interfaces. Two polymerization methods have been described: dry (yields highly conductive, stiff product), wet (yields less conductive, soft product). We tested for the effects of dry and wet PEDOT on regenerating nerves. The goal is to optimize a material for better conduction within the interface while preserving nerve viability.

Methods: A 15 mm rat peroneal nerve gap was reconstructed with various materials (n=8 per group): Sham, Autograft, Decellularized nerve (DN), dry PEDOT polymerized on DN (dry PEDOT), wet PEDOT polymerized on DN (wet PEDOT) and Gap (gap not reconstructed). After 90 days of recovery, nerve specimens were obtained from midgraft and histologically assessed using qualitative techniques. Quantitative analysis was performed on all specimens. The following data were collected: neural area (m2), percent neural area (%), axon counts, and axon density (axon/m2). EMG and muscle force were also measured.

Results: All nerves successfully regenerated under the influence of PEDOT. Dry PEDOT had high action potential velocity, but lower muscle force, nerve score and neural area than autograft. Wet PEDOT demonstrated similar histological outcomes to the sham, although action potential velocity and muscle force were lower. Additionally, wet PEDOT showed better histological outcomes than dry PEDOT, as neural area and axon density were similar to autograft, the gold standard. (Table 1,2)

Conclusion: Peripheral nerve regeneration occurs in the presence of PEDOT. Favorable histological outcomes with wet PEDOT confirm some advantages for this method. Mechanical obstruction to axonal sprouting and elongation by the dry PEDOT is a possible explanation for the observed poorer histology outcomes. On the other hand, dry PEDOT afforded faster conduction. Based upon these results, we conclude that wet PEDOT is qualitatively and quantitatively superior to dry PEDOT, though the cost is some compromise in conductivity.

This work supported by the Department of Defense Multidisciplinary University Research Initiative Program (#W911NF0610218), the Plastic Surgery Educational Foundation Pilot Research Grant (#172613) and the National Institutes of Health T32 Training Grant (#GM0008616-11)

19176 Effect of Polymerization Methods on Peripheral Nerve Regeneration