Objective: To evaluate the Piezosurgery (PZS) ultrasonic bone dissector as an alternative to conventional drilling to implant the Vibrant Soundbridge transducer in the round window (RW) niche.
Study Design: Prospective noncontrolled study. Audiologic and surgical records analysis.
Methods: Eight patients with mixed hearing loss and previous unsuccessful otologic surgeries were recruited. A transcanal or transmastoid approach was used. Round window osteoplasty was performed with the PZS device to implant the VBS floating mass transducer for cochlear stimulation.
Results: The osteoplasty was performed safely with PZS, and all patients were successfully implanted. No sensorineural hearing deterioration occurred in all but 1 patient. The postoperative air conduction threshold was slightly higher than preoperatively because of minor middle ear transfer function changes. After fitting, patients continue to wear their speech processors full-time. The aided speech discrimination scores at conversational level ranged from 65 to 100%. Aided hearing threshold was 32.2 dB HL (preoperative threshold under earphones, 62.8 dB HL). One patient affected by congenital aural atresia had a posterior canalithiosis on the operated side that was successfully treated by the repositioning maneuver.
Conclusion: The PZS device proved to be effective for RW osteoplasty; floating mass transducer was successfully implanted in all patients. Audiologic results are comparable to those obtained from traditionally operated patients. Relative to conventional drilling, the PZS allows a safer osteoplasty because it does not produce any rotation or torque that reduces the risk of RW membrane injury. Although hearing was preserved in our sample, the potential inner ear risks need to be further evaluated in both experimental and clinical fields.