A retrospective European multicenter analysis of the functional outcomes after active middle ear implant surgery using the third generation vibroplasty couplers

Abstract

Purpose: To evaluate the safety and performance of three novel vibroplasty couplers that allow attachment of the floating mass transducer of a transcutaneous active middle ear implant (AMEI) to the round window (RW) membrane, the long process (LP), or the incus body and the short process (SP) of the incus.

Methods: Retrospective multicenter cohort study of 25 AMEI users with sensorineural or mixed hearing loss that were among the first implanted with an AMEI vibrating ossicular prosthesis in combination with the third generation of vibroplasty couplers between 2014 and 2016. Main Outcome Measures were bone-conduction pure-tone and vibroplasty thresholds, postoperative aided sound field thresholds and postoperative aided word recognition score (WRS).

Results: Bone conduction threshold changes of more than 10 dB in 4PTA_BC were observed in two subjects. A mean improvement of 57.8% in speech recognition was observed with a mean WRS at 65 dB SPL improving from 14.8% (SD 21.9%) preoperatively to a mean aided score of 72.6% (SD 18.6%). Sound field thresholds improved from an average 4PTA_SF of 64.1 dB HL (SD 9.8 dB HL) to 37.0 dB HL (SD 8.9 dB HL), resulting in a mean functional gain of 27.1 dB. There was no significant difference in WRS or functional gain between the coupler types.

Conclusion: Initial experience shows that all three third generation vibroplasty couplers represent safe and efficient attachment options for the FMT allowing the surgeon to choose the coupling type based on the present pathology.

Keywords: Active middle ear implant; Couplers; Hearing loss; Vibrant Soundbridge; Vibroplasty.

Fig. 1

Coupler types and placement. a LP-coupler, b SP-coupler, c RW-soft-coupler

Fig. 2

Changes in bone conduction thresholds. Preoperative and the latest available postoperative measurement for 4PTA_BC. Changes above the 10 dB test–retest range (gray lines) are considered significant

Fig. 3

Speech recognition. a Unaided (latest available measurement, open symbols) and AMEI aided (postoperative, closed symbols) WRS at 65 SPL. b. Postoperative AMEI aided WRS at 65 (open symbols) and 80 dB SPL (closed symbols). Horizontal dotted lines indicate the mean WRS and standard deviation. No significant difference in WRS was observed between coupler types at 65 dB SPL (Kruskal–Wallis test, p = 0.23). Please note that the figure assembles results of speech recognitions tests from different languages

Fig. 4

Sound field thresholds. Preoperative unaided 4PTA_SF (open symbols) were compared to postoperative aided 4PTA_SF (closed symbols). Horizontal lines indicate the mean 4PTA_SF and standard deviation

Fig. 5

Coupling quality. The comparison of bone conduction and vibrogram thresholds can be used to assess coupling efficiency. An optimal coupling is indicated by the full line. The larger the perpendicular distance from this line to the left, the poorer is the coupling quality. Limited available data suggest that a difference of greater than 20 dB is associated with a higher risk of unsatisfactory word recognition scores [23]. The 10, 20 and 30 dB differences are shown in gray and dashed as guiding lines