Functional and aesthetic defects in the head, neck, and airway that result from cancer surgery, trauma, or congenital malformations have led to the development of surgical techniques to reshape cartilage in order to restore or recreate damaged or absent structures. Conventional surgical techniques involve cutting, carving, or even morselizing cartilage tissue—each of which requires classic open operations, with all the attendant medical risks and costs. We are exploring electromechanical reshaping (EMR) as a novel tissue-reshaping technique that combines mechanical deformation with the application of electric fields. In a typical embodiment of EMR, a cartilage sample is held in mechanical deformation by a jig, needle electrodes are inserted into the tissue, and a constant potential is applied for 2-3 minutes. When the electrodes and jigs are removed, the cartilage assumes a new shape that approximates the geometry of the jig (for example, a 90o bend). Although several possible mechanisms may play a role (e.g., non-Faradaic protein and/or ion migration through the tissue caused by applied voltage gradients) our work suggests that the dominant pathway involves water electrolysis (and acidification) at the tissue/solution interface: (1) no EMR occurs unless at least one electrode in contact with the cartilage is held at a potential positive of the water-oxidation limit; (2) EMR does not require a voltage gradient across the tissue; and (3) the magnitude of EMR correlates directly with total anodic charge transferred (as opposed to electrolysis time, applied potential, voltage gradient, etc.). In this talk, we correlate the degree of tissue reconstruction with empirical maps of electrochemically generated pH gradients in mechanically strained tissue; we additionally present landscapes for reactive-oxygen species associated with the electrolysis process. Taken together, these results provide a roadmap for optimizing the conditions for effective shape change while minimizing tissue morbidity and mortality.

Electromechanical tissue reconstruction: A non-invasive surgical modality for reshaping cartilage of the head and neck

249th National Meeting (2015)

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