Steigbügelchirurgie

Audiological outcome after stapes surgery in relation to prosthesis type

PURPOSE

Different techniques are used to fix crimp and CliP® Piston stapes prostheses to the long process of the incus (LPI). The CliP® Piston provides a stiff connection in contrast to the static bended loop of the crimp prosthesis, which imitates the physiological incudostapedial joint (ISJ) and thereby potentially leads to different hearing outcome.

METHODS

In a retrospective single-center study of German-speaking one hundred and ninety patients who underwent stapes surgery CliP® Piston or crimp prostheses between the years of 2016 and 2019 by the same surgeon and in the same setting. Pre- and postoperative bone- (BC) and air-conduction (AC) pure-tone thresholds, pre- and postoperative air-bone gap (ABG) for 0.5, 1, 1.5, 2, 3, 4 kHz and the surgery time were examined.

RESULTS

The postoperative bone conduction thresholds were significantly lower in the frequencies between 0.5 and 3 kHz and the mean ABG was < 10 dB in most cases independent of the prosthesis used. Crimp prosthesis showed a significantly better closure of the ABG at 0.5 kHz.

CONCLUSIONS

The audiological outcome after stapes surgery is dependent on the type of prosthesis used, as reflected by the frequency-specific air-bone gap. The better ABG closure with the crimp prosthesis might be the result of the connection to the LPI imitating the physiological ISJ. The crimp prosthesis may be the better choice if use of hearing aids is expected postoperatively.

[Stapes surgery for otosclerosis using a new titanium prosthesis with a superelastic nitinol clip: First experiences]

BACKGROUND

Coupling of the prosthesis to the long process of the incus is a critical step in stapes surgery. We report first experiences with the NiTiFLEX® stapes prosthesis, a further development of the Soft CliP® stapes prosthesis (Kurz, Dusslingen, Germany). Instead of pure titanium, the CliP® now consists of nitinol, a superelastic nickel-titanium alloy. This further reduces the pressure exerted on the long process of the incus, aiming to improve coupling and minimize the risk of incus luxation.

METHODS

In a monocentric, retrospective cohort study, we evaluated air-bone gap reduction (4PTA0.5-4 kHz), understanding of monosyllables at 65 and 80 dB SPL stimulation levels, and adverse effects, such as changes in bone conduction (4PTA0.5-4 kHz). During a 12-month period (May 2014 to April 2015), stapes surgery was performed in 21 otosclerosis patients using the NiTiFLEX® prosthesis. The footplate was perforated using a CO2 laser (scanning mode; 0.7 mm; 20-21 W) in almost all cases. The diameter of the titan piston was 0.4 mm. Immersion at an angle of almost 90° thus results in a gap between the footplate perforation and the piston of 0.15 mm. Positioning onto the long incus process was performed with a 90°microhook (0.6 mm).

RESULTS

In all cases the NiTiFLEX® stapes prosthesis was inserted without complications. The mean bone conduction threshold did not change significantly postoperatively and the mean air-bone gap (4PTA0.5-4 kHz) improved on average from 29.0 to 9.5 dB HL. Handling of the prosthesis was rated as very good.

CONCLUSION

The limited experience of this study suggests that the NiTiFLEX® stapes prosthesis is a successful further development of the Soft CliP® technique with very good intraoperative handling qualities. While long-term results from larger studies are needed, this case series demonstrates that the hearing outcome is comparable to other prostheses.