Management of conductive and mixed hearing loss intolerant to air-conduction hearing aids: A stepwise algorithm and...

Conductive and mixed hearing loss in the complicated ear, including chronically inflamed ears with recurrent otorrhea, postoperative cavities, tympanic membrane lateralization, canal stenosis/atresia, and congenital malformations, remains a frequent, consequential problem in cases where conventional air-conduction hearing aids (ACHAs) are unusable or provide insufficient functional benefits. The expansion of the therapeutic landscape from non-implantable (e.g., cartilage conduction hearing aids [CCHA] and adhesive bone-conduction systems) to implantable (e.g., bone-conduction implants [BCIs] and active middle ear implants [Vibrant Soundbridge^®︎, VSB]) options has not only increased opportunities for personalized rehabilitation but also created a practical "paradox of choice." Japan provides a distinctive clinical context because major implantable auditory devices are reimbursed under defined indications, whereas access to non-implantable options frequently depends on out-of-pocket purchases and/or subsidy programs.

This Japan-based narrative review synthesized peer-reviewed evidence and integrated the domestic indication framework to propose a pragmatic, stepwise device-selection algorithm for complicated ears with conductive or mixed hearing loss. Step 1 comprises a Gatekeeper Trial using a non-surgical option (e.g., CCHA/adhesive systems or headband/soft band stimulation) to confirm real-world benefits, identify coupling-related limitations, and provide counseling. Step 2 categorizes the cochlear reserve into zones A, B, or C based on bone-conduction thresholds to align the device output capacity with the inner-ear reserve; this step also incorporates Japan-aligned indications and a high-frequency "B-C border" flag (e.g., >65 dB HL at high frequencies) that can shift the balance between BCI and VSB. Step 3 applies clinically decisive modifiers: ear status and infection-control strategy, imaging-based surgical feasibility, high-frequency listening demands, and patient priorities, such as cosmesis, skin tolerance, maintenance burden, and MRI considerations.

Asymmetric hearing loss is managed as a dedicated differentiator. When appropriate, BCI-mediated transcranial stimulation can add useful contralateral cochlear access to improve speech perception in relevant spatial noise configurations, whereas counseling emphasizes situation-dependent benefits and limited binaural restoration.

Finally, we introduce the concept of Device Readiness Surgery, reframing otologic surgery as a staged effort to achieve a safe, dry, and stable ear that enables ACHA use whenever realistic; when ACHA remains ineffective, the ear is optimized for the selected device. This review provides a clinically oriented roadmap to improve the consistency of counseling and device selection in complicated ears and highlights the priorities for prospective validation and comparative-effectiveness research.