MPR-CT Imaging for Stapes Prosthesis: Accuracy and Clinical Significance.

OBJECTIVES

The aims of this article are: 1) to re-evaluate the accuracy of multiple planar reconstruction computed tomography (MPR-CT) imaging on stapes-prosthesis parameters, and 2) to clarify possible relationships between prosthesis intravestibular depth and postoperative hearing outcomes.

PATIENTS: Seventy patients (46 women and 24 men; 32 right and 38 left sides) with the mean age of 40 years (range, 19-62 yr) with clinical otosclerosis.

INTERVENTION(S): All patients underwent stapedotomy and were implanted with the same type of titanium piston prosthesis by the same surgeon.

MAIN OUTCOME MEASURE(S): Postoperative MPR-CTs were obtained at patients' follow-up visits. The length and intravestibular depth of the stapes prosthesis (including absolute and relative depth) were calculated from the MPR-CT imaging. Relationships between the intravestibular depth of the prosthesis and hearing outcomes (pre- and postoperative audiograms) were analyzed using Spearman correlation analyses.

RESULTS

The length of the prosthesis was overestimated by 1.8% (0.1 mm) by the MPR-CT imaging. Axial and coronal measurements were significantly correlated (p < 0.05). There was great intersubject variability in hearing outcomes differed insignificantly, regardless of intravestibular depth within the security range. No relationships were found between the intravestibular depth of the stapes prosthesis, as measured with MPR-CT, and postoperative hearing results.

CONCLUSIONS

MPR-CT can provide an accurate estimation of stapes prosthesis parameters. However, the prosthesis intravestibular depth did not seem to affect postoperative hearing outcomes.