References
Audiological Aspects
Maximum stable gain (feedback noise)
1. "(...) [percutaneous bone conduction devices] are known to have limited gain due to feedback problems. Feedback oscillations occur when increasing the gain over a certain point as sound is radiated back from cranial bone and housing to the microphone."
2. "Main acoustic shortcomings included wind noise, speech in noise, and feedback." (Medical Advisory Secretariat 2002)
More: Busch et al. 2015
Medical Aspects
Problems with loss of abutment
1. "During a mean follow-up of 39 months (range, 0 to 144 months), 16 of the 248 implants were lost (6.5%). The causes were failed osseointegration in 9 cases, trauma in 6 cases, and implant loss in irradiated bone in 1 case." (de Wolf Maarten et al. 2009)
2. "Osseointegrated implants require frequent maintenance care from the surgeon. Complication rates are higher for children with a diagnosis of a craniofacial syndrome, and the risk of a complication increases significantly over a prolonged period of time." (Ida et al. 2011)
More: Wazen et al. 2008
Medical Aspects
Aesthetics / cultural issues
1. "The percutaneous abutment connection system is disadvantageous in terms of aesthetics, and regular hygiene and care of the surgical site are necessary." (Cho et al. 2020)
2. "Most patients found it unpleasant (...) to have an abutment in their skull that required diligent care." (Müller-Isberner et al. 2015)
More: Cooper et al. 2017, Lindsey 2009
Patient-reported Aspects
Skin complication / permanent wound care required
1. "Multiple studies reported postoperative skin irritations and wound infections due to the permanent skin penetration of the fixation screw." (Schilde et al. 2017)
2. "Surgically implanted bone anchored hearing aids that are directly anchored in the temporal bone circumvent these problems, but their use is associated with an increased risk of dermatological complications due to the penetration of the skin surface necessitating constant wound care." (Skarzynski et al. 2019)
3. "Approximately 20% of the patients suffered from skin irritations and in 5% of the cases surgical interventions were necessary to rehabilitate the skin complications." (de Wolf Maarten et al. 2008)
4. In this study with over 600 patients the Baha complication rate was 23,9%. (conclusion / Hobson et al. 2010)
5. Schwab et al. showed, that complications with a percutaneous device that necessitate revision surgery are also high - rates vary between 5,8% and 12,1% of cases. depending on study (conclusion / Schwab et al. 2019)
6. "Although some complications seem to decrease with new implant systems, one main issue is that it needs lifelong daily care."
7. Reyes et al. found that 30% of the patients with either an osseointegrated percutaneous bone conduction hearing implant or auricular prosthesis had at least one adverse skin reaction (conclusion / Reyes et al. 2000)
More: Shirazi et al. 2006, Wazen et al. 2008, Gluth et al. 2010, Shapiro et al. 2018, Kiringonda et al. 2013, Dun et al. 2012, Peters et al. 2014