**7. Surgical method of implant and timing**

The FDA recommends to apply the device in children not younger than 5 years. Authors say that the ideal age for implanting a BAHI is between 2 and 4 years, because at this age the thickness of retromastoid bone (2.5–3 mm) allows to perform a totally safe surgery, without risk of damaging the dura. Additionally, regarding the age of implant, we have to consider that children need to possess a sufficient manual dexterity to maintain the device and a good psychological tendency to follow the suggestions of parents and caregivers. We usually correct hearing aids before 5 years by using an elastic band (Softband).

The Tjellström et al. technique, proposed in 1977, suggest the creation of a thin muscle-cutaneous flap. The main disadvantage is an altered vascularization that may lead to infection and wound healing problems, dysesthesia in the retroauricular area and alopecia. For solving these problems, a less invasive technique by using a linear retro-auricular incision has been proposed and currently is the mostly used. The main benefit of this new technique is the good preservation of the vascularization in the surgical area that allows to avoid all the problems of muscle-cutaneous flap (infection, healing problems, dysesthesia, etc.). Another suggested low invasive technique is based on the removal of a very small piece of skin in the area in which the titanium implant should be placed. The skin removed has the same dimension of a biopsy. This technique also presents the advantages of the liner incision, due to the reduced trauma on tissue and vascular structures [30].
