Anterior clinoidectomy and opening of the internal auditory canal using an ultrasonic bone curette

During cranial base surgery, use of a high-speed drill for osteotomy has become common. We performed anterior clinoidectomy and opening of the internal auditory canal using an ultrasonic bone curette, and we report the advantages and clinical applications of this method. The ultrasonic surgical equipment comprises a power supply unit, footswitch, and handpiece (weight, 110 g; diameter, 20 mm; length, 140 mm from tip to angled section). The handpiece tip is 2 mm wide, and the amplitude of longitudinal vibration can be varied from 120 to 365 microm at an ultrasonic frequency of 25 kHz. Cool-controlled irrigation fluid emerges near the tip, through the sheath. We performed anterior clinoidectomy in eight cases of paraclinoid aneurysm and opening of the internal auditory canal in six cases of acoustic neuroma without damage to the dura mater or nearby structures such as brain tissue, blood vessels, and cranial nerves. In addition, no damage to the facial nerve or labyrinthine organ resulted from heat or vibration caused by the ultrasonic bone curette. Ultrasonic bone curettage represents safe instrumentation for performance of anterior clinoidectomy and opening of the internal auditory canal without damage to surrounding structures. This technique allows surgeons to perform procedures on deep areas without incurring psychomotor stress.