Modified Incisions for Reduction of Soft Tissue for One‐Stage, Bone‐Anchored Hearing Aid Implantation

The majority of patients who require a hearing aid can be fitted with an air-conduction hearing aid. If an air-conduction hearing aid cannot be used because of recurrent otorrhea or atresia of the auditory canal, it may be possible to fit a bone-conduction hearing aid. An alternative to the conventional bone-conductor aid is the bone-anchored hearing aid (BAHA). The BAHA has both cosmetic and acoustic advantages over any conventional aid and hence is a popular choice today. 1. The BAHA is coupled to a percutaneous titanium implant anchored in the temporal bone. The absence of interposing soft tissues (direct bone conduction) gives better quality sound, requires less energy, and offers much greater comfort. 2. A skin graft of thin non–hair-bearing skin is required at the implant site. Insertion of percutaneous implant into the temporal bone for the coupling of a BAHA can be performed in two stages. Most centers perform a one-stage procedure in adults and a two-stage procedure in children. We have found that a one-stage procedure with the following modification allows the avoidance of a two-step procedure and reduces other wound-related complications. We believe this enables quicker healing and ensures timely fitting of the BAHA. The surgical steps can be divided into anesthesia and skin preparation, incision and soft tissue reduction, placement of fixtures, skin graft replacement, abutment positioning, and dressings and aftercare. 1. The procedure is performed with the patient under local anesthesia (except in children). 2. We describe modified incisions to facilitate soft tissue reduction under direct visual control. An area of circular skin 1.5 to 2 cm in diameter is excised and subcutaneous tissue under this area is removed to allow the edges of the skin to drop down to the periosteum without any tension (as an alternative, a split-thickness skin graft or an inferiorly based skin flap can be harvested or raised at the implant site). 3. Soft tissue reduction around this circular island is facilitated by four radial incisions 1 cm in length extending from the circumference (Fig. 1). 4. Soft tissue reduction is performed under direct visual control with a cutting diathermy and hemostasis is achieved using a coagulation diathermy (Fig. 2). The soft tissue reduction must be generous, especially in the superior semicircle. Ignoring this step would result in the soft tissue's sagging with gravity, which may interfere with the fit of the aid. 5. The drilling procedure and insertion of the flange fixture are performed by the standard Branemark technique. 6. A free skin graft is harvested from the postauricular skin, thinned to remove roots of hair follicles, and sutured over the fixture. The skin around the implant then makes direct contact with bone tissue. 7. A skin biopsy punch is used to puncture the graft and the abutment is placed on the fixture, which penetrates through the skin graft. 8. A healing cap is fitted over the abutment. A dressing is placed around the cap that includes half-inch ribbon gauze soaked in steroid-antibiotic ointment. This is carefully and meticulously packed around the healing cap to appose the skin graft to the periosteum. A pressure dressing is applied for at least 24 hours. Clinical appearance of the circular island for skin and soft tissue excision and the markings for the four-flap soft tissue reduction technique. Operative view showing elevation of the flaps to facilitate circumferential soft tissue reduction (doughnut shaped) under direct visual control. The surgery is performed as a day case and the patient is advised to remove the bandage the following day. The dressing is removed after 7 days and the patient and partner are advised regarding care of the wound and skin around the prosthesis. The hearing aid is fitted in 3 months' time. Reduction of soft tissue around a circumferential incision (back-cuts and under-cuts to the free skin edge) on a vascular area such as the scalp could be quite difficult unless carried out under direct visual control. The management of soft tissue around the implant site is a crucial step in the surgery to achieve immobility of the skin around the penetrating abutment. This is vital for long-term care and maintenance of the fixture-abutment assembly by the patient. 3. If this is not undertaken adequately and accurately, the soft tissues including the temporalis and occipitalis muscles tend to sag and prolapse onto the abutment, with time. 3. We believe the described technique is a useful method of avoiding wound revision surgery at the implant site. Since 1994, the senior author (t.n.r.) has used this modified incision to achieve soft tissue reduction under direct vision in 34 patients. Figure 3 shows the postoperative appearance of the operated area in one patient. To date we have not had any patient requiring revision surgery for further soft tissue reduction at the implant site. Postoperative view showing satisfactory apposition of skin graft and circumferential flaps to underlying periosteum.