Beyond the surface: exploring contributing factors to bone anchored hearing implant complications

Bone anchored hearing implants (BAHI) are considered for conductive and mixed hearing loss, relying on osseointegration of a titanium implant. Limitations relate to constant skin contact, with resultant percutaneous infections and granulation. This study investigates whether patient characteristics and implant-specifications contribute to BAHIs' skin complications in a cohort with a uniform surgical approach.

A 10 year (2014-2024) retrospective cohort study was conducted on BAHI procedures that were undertaken using a tissue-preserving 'punch' technique. Data on patient demographics, co-morbidities, implant type, surgical approach, and complications were collected. Poisson regression analysis was used to identify predictors of complications.

A total of 53 patients undergoing 55 BAHI surgeries by three ENT consultants were included. Factors that greatly increased implant-related percutaneous infections included the Cochlear™ BIA400 implant when compared to the Ponto™ BHX implant (twofold, CI 2.03-2.16), abutment sizes ≤ 10 mm (fourfold, CI 3.99-4.12) and male gender (9%, CI 1.07-1.12). Granulation episodes were affected by cardiovascular disease (CVD) status (1.5-fold, CI 0.26-0.78), BIA400 implant (threefold, CI 8.8.-9.2) and abutment sizes ≤ 10 mm (fourfold, CI 3.6-3.73). Revision surgery episodes increased with diabetic status (1.2-fold, CI 0.06-0.37) and abutment sizes ≤ 10 mm (threefold, 3.303-3.304).

Larger cohort studies are required to confirm findings, particularly for implant and abutment size contributions. However, the findings suggest that using a larger abutment size when skin thickness meassuremets are borderline, improved hygiene education in male patients, pre-operative optimisation of CVD and diabetes, and adjusted patient follow-up based on risk stratification of the contributing factors to complication rates could reduce complication rates.