The influence of prosthesis diameter in stapes surgery: a meta-analysis and systematic review of the literature.

OBJECTIVE

To analyze the influence of stapes prosthesis diameter on postoperative hearing results after stapedotomy without interposition in otosclerotic patients.

DATA SOURCES

PubMed search from 1970 to 2009 using the key words stapedotomy or stapedectomy or otosclerosis or stapesplasty.

STUDY SELECTION

Inclusion criteria to select articles and patient groups for meta-analysis and statistical analyses were as follows: otosclerosis as diagnosis, clear description of technique and prosthesis size, calibrated stapedotomy, and complete report of functional results.

DATA EXTRACTION

Five controlled studies were found analyzing the influence of prosthesis diameter and reporting the results in a comparable way for meta-analysis (n = 590). Sixty-two studies not analyzing the influence of prosthesis diameter contained comparable subgroups with a total of 9,536 cases. These cases were pooled according to their diameter (0.3, 0.4, 0.5, 0.6,and 0.8 mm). The results of air conduction, bone conduction, air-bone gap (ABG), and success rate (closure of the ABG within 10 dB as percentage of the total cases) for all groups and frequency-specific ABG results were gathered. Furthermore, 12 clinical and experimental studies were reviewed that did not contribute to the statistical analysis.

DATA SYNTHESIS

A meta-analysis performed for success rate of the 5 controlled studies showed favorable results for 0.6-mm over 0.4-mm prostheses (success rate, 67% versus 58%, p = 0.05). In the statistical analysis of the pooled data, the 0.6-mm prosthesis showed better results compared with 0.4 mm (p < 0.001) in the postoperative air conduction threshold (29 dB versus 35 dB), postoperative ABG (7 dB versus 11 dB), ABG improvement (25 dB versus 21 dB), and success rate (81.1% versus 75.1%). The frequency-specific analysis of the postoperative ABG showed no advantage for the small prosthesis in the high frequencies. There was no difference in postoperative change of bone conduction in the 0.6- and 0.4-mm groups. Statistically significant results could not be assessed for other prosthesis diameters because of the small number of cases reported.

CONCLUSION

A 0.6-mm diameter piston prosthesis is associated with significantly better results than a 0.4-mm prosthesis and should be used if the surgical conditions allow it.