Editing Bone conduction (section)

===Surgical devices: active and passive===
An active bone conduction device is one where the implant generates the vibrations that directly stimulate the bone. With a passive bone conduction device, the vibrations are generated by the audio processor before being passed through the skin or an abutment to reach the implant and the bone.<ref name = "NDCS 2022-03-02">{{Cite web |title=Different types of surgical implant {{!}} Bone conduction hearing devices |url=https://www.ndcs.org.uk/information-and-support/childhood-deafness/hearing-implants/bone-conduction-hearing-devices/different-types-of-surgical-implant/ |access-date=2022-03-02 |website=www.ndcs.org.uk |language=en}}</ref> The main active bone conduction devices available are the BONEBRIDGE from MED-EL<ref name="Ears and Hearing UK 2022-03-02" /> and the Osia from Cochlear.<ref>{{Cite press release |last=Limited |first=Cochlear |title=FDA clears Cochlear's innovative new Osia® 2 hearing implant system |url=https://www.prnewswire.com/news-releases/fda-clears-cochlears-innovative-new-osia-2-hearing-implant-system-300970910.html |access-date=2022-03-02 |website=www.prnewswire.com |language=en}}</ref> Both are active transcutaneous devices. The external audio processor picks up sound vibrations and transmits them electronically through the skin to the internal implant, which directly and actively vibrates the bone. These vibrations are conducted through the skull bone to the cochlea and are processed as normal.<ref name="NDCS 2022-03-02" />

The main passive bone conduction devices are the BAHA Attract<ref>{{Cite web |title=Baha® Attract |url=https://ais.southampton.ac.uk/baha-attract/ |access-date=2022-03-02 |website=Auditory Implant Service |language=en-GB}}</ref> and BAHA Connect<ref>{{Cite web |title=Baha – The Implantable Hearing Device |url=https://www.hopkinsmedicine.org/otolaryngology/specialty_areas/hearing/hearing-aids/baha.html |access-date=2022-03-02 |website=www.hopkinsmedicine.org |language=en}}</ref> from Cochlear, the Ponto from Oticon<ref>{{Cite web |title=The Oticon Ponto System {{!}} A Complete Hearing Solution |url=https://berkshearing.com/oticon-ponto-system |access-date=2022-03-02 |website=berkshearing.com}}</ref> and the Alpha 2 MPO from [[Medtronic]].<ref>{{Cite web |title=Sophono Medtronic Alpha 2 MPO Processor |url=https://getremed.gr/προϊόντα/medical-products-en/office-equipment/audiology-equipment/audiological/sofono-alpha2/?lang=en |access-date=2022-03-02 |website=Getremed |language=en-US}}</ref> The BAHA Connect and Ponto are passive percutaneous devices, whereby the audio processor is fixed onto an abutment placed through the skin. The audio processor vibrates, sending the vibrations via the abutment to the implant and then through the bone to the cochlea.<ref name="NDCS 2022-03-02" /> The BAHA Attract and Alpha 2 are transcutaneous devices but they work in a similar way. The audio processor vibrates, sending mechanical vibrations to the implant through the bone. However, unlike with the percutaneous devices, the vibrations from the audio processor pass through the skin before they reach the internal implant. These vibrations are then conducted through the skull bones to the cochlea and are processed as normal, just like with an active device.<ref name="NDCS 2022-03-02" />

Active transcutaneous and passive percutaneous bone conduction devices tend to deliver better sound quality than passive transcutaneous ones. Passive transcutaneous devices send sound vibrations through the skin, and as they pass through the skin, they lose some of their strength, causing [[signal attenuation]] of up to 20[[Decibel|dB]].<ref name="Ellsperman, Susan E. 2021-05-18" /> To counteract this, passive transcutaneous devices may require the use of strong magnets that squeeze the skin to achieve optimal conduction. This can lead to pain and irritation of the skin and [[soft tissue]] between the two magnets, and in worst cases cause [[necrosis]].<ref name="Ellsperman, Susan E. 2021-05-18" /> A study found that major complications—defined as complications requiring active management, such as post-operative [[seroma]], [[hematoma]], wound infections, skin [[ulcer]]ations, and [[Wound dehiscence|dehiscence]]—were found in 5.2% of cases.<ref>{{Cite journal |last1=Cooper |first1=Timothy |last2=McDonald |first2=Brendan |last3=Ho |first3=Allan |date=October 2017 |title=Passive Transcutaneous Bone Conduction Hearing Implants: A Systematic Review |journal=Otology & Neurotology|volume=38 |issue=9 |pages=1225–1232 |doi=10.1097/MAO.0000000000001518 |issn=1537-4505 |pmid=28719403}}</ref>