**5. Available product**

The hearing restoration by bone stimulation did not obtain an immediate success; in fact in 1920 the first electronic implantable device was the preferred method, and bone stimulation prostheses were considered as the last alternative. Furthermore, after the Second World War, with the advent of transistor, the electronic prosthesis became smaller and more manageable, similar to the actual hearing aids. Anyway, in the recent decades, thanks to the new discoveries which better explained the physiologic stimulation of the inner by bone stimulation and to the improved technologies that miniaturize the systems and make the system implantable (BAHI **Figure 3**), the system is widely used for the treatment of hearing impairments [21, 22]. BAHI solved the old problems related to the external bone stimulation as the difficulties in maintaining constant position and correct pressure on the mastoid and, in addition, the reduced bone stimulation due to the skin impedance [23, 24].

In the light of multiple observations and experiments, it was concluded that the bone pathway is a type of natural sound conduction and that the sound characteristics are normal and quite similar to that conducted by air.

The BAHI solves the problems of the traditional retro-auricular bone stimulation as poor performance due to inadequate contact between the vibrator and the skin, pain or decubitus at the site of contact, and poor esthetic acceptance of arch prostheses by combining a pin implanted in the temporal bone with an external transducer; the vibration of the transducer on the bone induces a stimulation of the inner ear cells with consequently sound perception.

**79**

**Figure 5**

**Figure 4.**

*Congenital Aural Atresia: Hearing Rehabilitation by Bone-Anchored Hearing Implant (BAHI)*

*On the top of the image, a semi-implantable transcutaneous device BONEBRIDGE (Medel) and on the bottom* 

*another model of transcutaneous BAHI ALPHA 2 by SOPHONO (Medtronic).*

*DOI: http://dx.doi.org/10.5772/intechopen.88201*

*Percutaneous BAHI (PONTO) produced by Oticon Medical.*

**Figure 3.** *On the left side, the transcutaneous BAHI, and on the right side, the percutaneous.*

*Congenital Aural Atresia: Hearing Rehabilitation by Bone-Anchored Hearing Implant (BAHI) DOI: http://dx.doi.org/10.5772/intechopen.88201*

**Figure 4.** *Percutaneous BAHI (PONTO) produced by Oticon Medical.*

**Figure 5**

*On the top of the image, a semi-implantable transcutaneous device BONEBRIDGE (Medel) and on the bottom another model of transcutaneous BAHI ALPHA 2 by SOPHONO (Medtronic).*

*Advances in Rehabilitation of Hearing Loss*

**5. Available product**

impedance [23, 24].

Based on our experience and according to the Jahrsdoerfer study, we can affirm that patients with CAA and a score of < 7 rarely benefit from an external and middle ear reconstruction with good functional results. In such cases, the implantation of a BAHI is a viable option for obtaining a stable, satisfactory, and long-term result in terms of hearing function recovery [18]. In conclusion we think that BAHI could be quite always the best method for restoring hearing function in patients with CAA,

The hearing restoration by bone stimulation did not obtain an immediate success; in fact in 1920 the first electronic implantable device was the preferred method, and bone stimulation prostheses were considered as the last alternative. Furthermore, after the Second World War, with the advent of transistor, the electronic prosthesis became smaller and more manageable, similar to the actual hearing aids. Anyway, in the recent decades, thanks to the new discoveries which better explained the physiologic stimulation of the inner by bone stimulation and to the improved technologies that miniaturize the systems and make the system implantable (BAHI **Figure 3**), the system is widely used for the treatment of hearing impairments [21, 22]. BAHI solved the old problems related to the external bone stimulation as the difficulties in maintaining constant position and correct pressure on the mastoid and, in addition, the reduced bone stimulation due to the skin

In the light of multiple observations and experiments, it was concluded that the bone pathway is a type of natural sound conduction and that the sound characteris-

The BAHI solves the problems of the traditional retro-auricular bone stimulation as poor performance due to inadequate contact between the vibrator and the skin, pain or decubitus at the site of contact, and poor esthetic acceptance of arch prostheses by combining a pin implanted in the temporal bone with an external transducer; the vibration of the transducer on the bone induces a stimulation of the

even in the case of high score in the Jahrsdoerfer grading system.

tics are normal and quite similar to that conducted by air.

inner ear cells with consequently sound perception.

*On the left side, the transcutaneous BAHI, and on the right side, the percutaneous.*

**78**

**Figure 3.**

The coupling between the pin and the transducer determines the type of BAHI: percutaneous or transcutaneous. Both methods of implant need a surgery.

The difference between the transcutaneous and the percutaneous system is the way in which the titanium screw is placed related to the skin plan; in the first one, the skin is surgically open, and the abutment is placed directly on the mastoid; then the surgical opening is closed by suturing the skin [25]. The percutaneous system instead consists of a titanium implant placed "through" the skin by perforating it [26].

All BAHI systems are composed of three main components:


All systems currently available on the market present these characteristics: high amplification power, working independently in the presence/absence of the ear canal and middle ear, a direct bone transmission giving a clear sound, may be tested preoperatively, and all systems being quite similar in terms of comfort [27–29] (**Figures 3–5**).
