The functional and esthetic defects in the head and neck that result from surgery, trauma, or congenital malformations have led to the development of surgical techniques to reshape cartilage. Conventional reconstructive techniques (e.g., otoplasty, rhinoplasty, tracheoplasty) involve the grafting or shape modification of cartilage (harvested from the ear, nasal septum, or rib). The disadvantages of these approaches include donor site morbidity from graft harvest, waste of excess graft tissue, shape memory effects, and lack of control over warping, particularly in costal cartilage tissue. Alternative approaches include enzymatic digestion in situ and laser reshaping. Of these, laser has received the most attention.
University of California researchers have developed a low cost alternative to laser reshaping. The invention is a method and apparatus for reshaping cartilage via radiofrequency (RF) energy. In the present technology, cartilage is heated by RF energy via electrodes in contact with the cartilage (inserted within or on the surface). The cartilage is heated until the stress relaxation temperature is reached in the tissue as determined by optical and/or acoustical monitoring. Further aspects of the invention include electrodes shaped to the final desired cartilage shape, and wherein the electrodes are integrated with clamps, jigs or scissors to perform the additional roles of holding and deforming both cartilage grafts and cartilage tissue in situ (e.g. tracheal rings in the airway). In other embodiments of the present invention, an array of electrodes are used to heat the cartilage, wherein the array electrodes may be activated either sequentially or in parallel depending upon the desired thermal field. Monitoring of the stress relaxation temperature may occur by various means, including direct measurement of the temperature, measurement of the changes in the light scattering properties of the cartilage as stress relaxation occurs, and measurement of changes in cartilage physical properties (density, electrical resistance and acoustic properties).
|United States Of America||Issued Patent||6,589,235||07/08/2003||2001-388|