Patterns of failure in heat-activated crimping prosthesis in stapedotomy.

Objective: To understand potential causes of failure in heat-activated crimping prosthesis in stapedotomy.

Study Design: Retrospective chart review of all primary and subsequent revision stapedotomy operations performed by the senior authors with heat-activated-crimping prosthesis between June 2003 and September 2009. Patients who had history of previous stapedotomy performed elsewhere were excluded.

Setting: Private neurotologic tertiary referral center.

Patients: The 335 primary stapedotomies reviewed included 190 with a SMart prosthesis and 145 with a manual-crimp De La Cruz prothesis. Twenty-one patients in the SMart prosthesis group underwent revision stapedotomy. Six patients in the De La Cruz prosthesis group underwent revision stapedotomy. Average length of time between initial and revision surgery for each prosthetic group was 16.5 months and 11 months, respectively.

Intervention: Primary and revision stapedotomy using heat-activated nitinol (SMart) or manual crimp-on platinum (De La Cruz) prosthesis.

Results: A total of 190 primary stapedotomies using heat-activated crimping prosthesis were performed between this period. There were 21 patients who had initial good hearing results that required revision or replacement with a different type of prosthesis. A common finding was lateral displacement of the prosthesis from the stapedotomy with detachment of the nitinol hook from the incus. This group of patients was compared with a control group that used manual-crimp prosthesis.

Conclusion: Heat-activated crimping prosthesis has been reported to enhance stapedotomy hearing outcomes on short- and long-term follow-up studies. Longitudinal analysis on its complications has not been reported. This case series demonstrated 11% rate of possible lateral displacement of the prosthesis out of the vestibule and/or incus. Reopening of the nitinol hook off the incus also was a common associated finding. Failure rates are classified. The advantages and disadvantages of this popular prosthesis are reviewed.