An instrument for ablation of tissue. The instrument including: a body
having at least one surface for contacting a tissue surface, the at least
one surface being substantially planar; an ultrasonic transducer disposed
in the body for generating ultrasonic energy and directing at least a
portion of the ultrasonic energy to the tissue surface, the ultrasonic
transducer being operatively connected to an ultrasonic generator; at
least one radio-frequency electrode disposed on the at least one surface
for directing radio frequency energy to the tissue surface, the at least
one radio-frequency electrode being operatively connected to a power
source; and one or more switches for selectively coupling at least one of
the ultrasonic transducer to the ultrasonic generator and the at least
one radio-frequency electrode to the power source.