Laser-assisted fixation of a nitinol stapes prosthesis.

BACKGROUND AND OBJECTIVE: Otosclerosis is an inner ear bone disease characterized by fixation of the stapes and consequently progressive hearing loss. One treatment option is the surgical replacement of the stapes by a prosthesis. When so called "smart materials" like nitinol are used, prosthesis fixation can be performed using a laser without manual crimping on the incus. However, specific laser-prosthesis interactions have not been described yet. The aim of the present study was to elucidate the thermo-mechanical properties of the NiTiBOND® prosthesis as a basis for handling instructions for laser-assisted prosthesis fixation. STUDY DESIGN AND MATERIALS AND METHODS: Closure of the NiTiBOND® prosthesis was induced ex vivo by either a diode laser emitting at λ = 940 nm or a CO2 laser (λ = 10,600 nm). Total energy for closure was determined. Suitable laser parameters (pulse duration, power per pulse, distance between tip of the laser fiber and prosthesis) were assessed. Specific laser-prosthesis interactions were recorded. RESULTS: Especially the diode laser was found to be an appropriate energy source. A total energy deposit of 60 mJ by pulses in near contact application was found to be sufficient for prosthesis closure ex vivo. Energy should be transmitted through a laser fiber equipollent to the prosthesis band diameter. Specific deformation characteristics due to the zonal prosthesis composition have to be taken into account. CONCLUSION: NiTiBOND® stapes prosthesis can be closed by very little energy when appropriate energy sources like diode lasers are used, suggesting a relatively safe application in vivo. Lasers Surg. Med. 50:153-157, 2018. © 2017 Wiley Periodicals, Inc.

Promising clinical results of an innovative self-crimping stapes prosthesis in otosclerosis surgery.

OBJECTIVES: This clinical study was performed to retrospectively analyze the hearing improvement of patients with otosclerosis who underwent stapesplasty with a novel nitinol prosthesis in comparison with the use of already established prostheses (titanium and clip prostheses) and to evaluate the suitability of the nitinol prosthesis for ear surgeons with limited experience in otosclerosis surgery. STUDY DESIGN: Retrospective data analysis. SETTING: Tertiary referral center. PATIENTS: Sixty patients who underwent otosclerosis surgery between July 1, 2010, and June 30, 2012, in the ENT department of the University of Munich. Two patients were operated on both sides. For four patients, the stapesplasty was a revision surgery. INTERVENTIONS: Sixty-two procedures of otosclerosis surgery were performed by 6 ear surgeons, one of whom with profound experience in stapesplasty. MAIN OUTCOME MEASURES: 1) Postoperative air-bone gap, determined for all surgeons together as well as itemized for the experienced and the nonexperienced stapes surgeons; 2) closure of the air-bone gap in 10 dB bins; and 3) change of high-tone bone-conduction level. RESULTS: Pure-tone audiometry documented less postoperative air-bone gap and a higher percentage of air-bone gap closure when using the nitinol prosthesis, especially in comparison with the clip prosthesis. Also, nonexperienced stapes surgeons received better audiometric results when using the novel nitinol prosthesis. CONCLUSIONS: Clinical evaluation suggests the novel nitinol prosthesis to be a promising tool in otosclerosis surgery for experienced stapes surgeons as well as for ear surgeons with limited experience in stapes surgery.