**6. Temporal bone anatomy and BAHI**

Surgeons have to keep in mind the normal anatomy of temporal bone because it is helpful for remembering the anatomic landmarks when severe malformations occurred in the patient that should be implanted.

When CAA is associated with microtia, the main anatomic landmarks are the zygomatic process (image 7 sagittal plane view); in fact this structure is generally quite preserved also in the case of craniofacial malformation.

In the case of the absence of zygomatic process, the squamosal suture should be identified as alternative landmarks (**Figure 6**).

#### **Figure 6.**

*The normal anatomy of human temporal bone in sagittal and coronal views. The red circle indicates the zygomatic process, the only landmark that may be present in the case of CAA associated with craniofacial malformation (Figures 7***–***9).*

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**Figure 9.**

*used as an alternative to zygomatic arch.*

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

*The image shows the squamosal suture in a normal head. In the left side the cranium of a child before the* 

*CT scan high-resolution images. (A) Type D CAA with preservation of the normal mastoid pneumatization. The red arrow indicates the squamosal suture. (B) Type D CAA with absence of mastoid pneumatization; the* 

*(A) CAA in a non-syndromic patient with complete preservation of zygomatic arch anatomy (red rectangle). (B) CAA in a syndromic patient; the zygomatic arch is extremely malformed (red rectangle) and cannot be used as a surgical anatomic landmark. The squamosal suture is well identifiable (yellow arrow) and can be* 

*closure of the suture; in the right the squamosal suture as appears in the adult head.*

*red arrow shows the clear presence of the squamosal suture that is still not closed.*

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

**Figure 7.**

**Figure 8.**

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

**Figure 7.**

*Advances in Rehabilitation of Hearing Loss*

behind the ear

**6. Temporal bone anatomy and BAHI**

occurred in the patient that should be implanted.

identified as alternative landmarks (**Figure 6**).

quite preserved also in the case of craniofacial malformation.

The coupling between the pin and the transducer determines the type of BAHI:

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].

1.An internal titanium fixture that is surgically anchored to the temporal bone

2.An external abutment that is connected to the implant at the time of surgery

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**).

Surgeons have to keep in mind the normal anatomy of temporal bone because it is helpful for remembering the anatomic landmarks when severe malformations

When CAA is associated with microtia, the main anatomic landmarks are the zygomatic process (image 7 sagittal plane view); in fact this structure is generally

In the case of the absence of zygomatic process, the squamosal suture should be

*The normal anatomy of human temporal bone in sagittal and coronal views. The red circle indicates the zygomatic process, the only landmark that may be present in the case of CAA associated with craniofacial* 

percutaneous or transcutaneous. Both methods of implant need a surgery.

All BAHI systems are composed of three main components:

3.An external sound processor that is snapped on to the abutment

**80**

**Figure 6.**

*malformation (Figures 7***–***9).*

*The image shows the squamosal suture in a normal head. In the left side the cranium of a child before the closure of the suture; in the right the squamosal suture as appears in the adult head.*

#### **Figure 8.**

*CT scan high-resolution images. (A) Type D CAA with preservation of the normal mastoid pneumatization. The red arrow indicates the squamosal suture. (B) Type D CAA with absence of mastoid pneumatization; the red arrow shows the clear presence of the squamosal suture that is still not closed.*

#### **Figure 9.**

*(A) CAA in a non-syndromic patient with complete preservation of zygomatic arch anatomy (red rectangle). (B) CAA in a syndromic patient; the zygomatic arch is extremely malformed (red rectangle) and cannot be used as a surgical anatomic landmark. The squamosal suture is well identifiable (yellow arrow) and can be used as an alternative to zygomatic arch.*
