An improved apparatus and method of securing body tissue may be performed with a robotic mechanism. The robotic mechanism may be utilized to tension a suture with a predetermined force and urge a suture retainer toward body tissue with a predetermined force. Ultrasonic vibratory energy may be transmitted to the suture retainer to effect a gripping of the suture by the suture retainer. The body tissue may be secured with a staple. Legs of the staple may be bonded together to secure the staple. The legs of the staple may be bonded together by transmitting ultrasonic vibratory energy to the legs of the staple. A tissue positioning assembly may be used to hold the body tissue in a desired position. Images of the body tissue being secured may be obtained using various known devices including one or more endoscopes, a fluoroscope, a magnetic resonance imaging device, and/or other known imaging devices.