Effect of piston diameter in stapedotomy for otosclerosis: a randomized controlled trial.

Rationale: otosclerosis is characterized by bony deposits in the middle ear, resulting in stapes fixation and progressive hearing loss. It can be treated effectively by surgically removing (part of) the stapes and replacing it with a prosthesis/piston. Since Shea first introduced stapes surgery as a treatment option for otosclerosis in 1956, a large number of prostheses or pistons have been developed. Shape, size and type of material have been the main focus in enhancing pistons. The piston shaft diameter ranges from 0.3 mm up to 0.8 mm. Available evidence from clinical studies, mathematical models and temporal bone studies suggests that a larger diameter piston is associated with better hearing outcomes. However, a lack of high quality, clinical studies precludes firm evidence based recommendations.



Objective: the primary objective of this study is to evaluate the effectiveness of two differently sized pistons used in primary stapedotomy for otosclerosis in terms of hearing improvement, general and disease-specific quality of life and complication rate.



Study design: double-blinded randomized controlled trial. Both patients and outcome assessors are blinded.



Study population: adult otosclerosis patients, aged 18 years and over, who are eligible for primary stapedotomy.



Intervention: primary stapedotomy, either with a 0.4 mm diameter piston or a 0.6 mm diameter piston.



Main study parameters/endpoints: primary outcome measure is postoperative air-bone gap closure on pure-tone audiometry at 12 months follow-up. Secondary outcome measures are hearing improvement on pure-tone and speech audiometry, disease-specific and general quality of life and complications (with specific attention for tinnitus and vertigo).



Nature and extent of the burden and risks associated with participation, benefit and group relatedness: compared to routine clinical practice, the study requires that half of the participants receive a 0.6 mm diameter piston instead of a 0.4 mm diameter piston. A larger diameter piston might be more beneficial based on the available evidence with regard to hearing outcome.

The use of a larger diameter piston in stapedotomy for otosclerosis is associated with superior hearing outcomes compared to the use of a smaller diameter piston, while maintaining equal rates of adverse events.

Follow-up directly postoperatively, at three months postoperatively and at one year postoperatively. Furthermore a monthly costs diary will be fulfilled.

Primary stapedotomy, either with a 0.4 mm diameter piston or a 0.6 mm diameter piston.