Replacing BAHA With BCI 602: Surgeons Agree on International Guidelines

Fewer complications, no permanent wound, intact skin, maximum wearing comfort, and outstanding reliability—the advantages of the active, transcutaneous BONEBRIDGE bone conduction implant speak for themselves.

As opposed to percutaneous bone conduction implants that send vibrations to the bone skull through a screw that penetrates the skin, BONEBRIDGE combines the advantages of active stimulation with transcutaneous technology. The external audio processor sends signals through the intact skin to the implant, which produces vibrations that are transmitted directly to the bone. And because the microphones in the SAMBA 2 audio processor communicate with the BCI 602 via induction—but are physically separated—irritating feedback, which can be an issue for percutaneous systems, is prevented.

International Guidelines for Conversions From BAHA to BCI 602

When it comes to hearing success and reliability, BONEBRIDGE is the clear winner over percutaneous systems.Systematic review and meta-analysis of audiological and patient-reported outcomes with the BONEBRIDGE active bone conduction implant system. MED-EL 2022: https://go.medel.pro/OutcomesBB[1] The increased risk of complications, extrusion and infection that comes with percutaneous bone conduction systems are to replace BAHAs with BONEBRIDGE implants.

Once the decision to explant BAHA and then implant BONEBRIDGE has been made, then the question about “how” arises. In the past, a variety of approaches and methods had been used, but just a few months ago, leading ENT surgeons from Europe and South America reached an international consensus about the recommended approach.

The participating surgeons were:

• Javier Gavilán, Hospital Universitario La Paz, Spain
• Burkhard Schwab, Helios Klinikum Hildesheim, Germany
• Mario Zernotti, Universidad Católica de Córdoba, Argentina
• Carlos Curet, National University of Cordoba, Argentina
• Diego Marcomini, Sanatorio Franchin, Argentina
• Andrea Albera, Città della Salute e della Scienza di Torino, Italy
• Andrea Canale, Città della Salute e della Scienza di Torino, Italy
• Arthur Castilh, Unicamp Hospital de Clinicas Campinas, Brazil

The result is clear: despite the varying backgrounds of the participants (different clinical procedures, surgical schools, healthcare systems, etc.), they were able to come to a consensus about procedures and document them in the form of surgical guidelines: Conversion Type 1 and Conversion Type 2.

Preoperative Analysis and Classification of the Complications as Criteria

About 10% of people with a BAHA report major complications caused by the implant.Safety outcomes of bone conduction and middle ear implants: A systematic review, rev. 5.0. MED-EL 2020.[5] These complications are often infections or inflammation that cause damage to multiple layers of skin and lead to limited or discontinued use of the implant. The decision between Type 1 and Type 2 is made prior to BAHA explantation and is based on the reason for the conversion and the complications diagnosed preoperatively.

To make it easier to assess the severity of the complications, the guidelines rely on the Holgers scale: Grade 0 (no skin reaction), Grade 1 (redness with slight swelling), Grade 2 (redness, moistness, and moderate swelling), Grade 3 (redness, moistness, and moderate swelling with granulation tissue), Grade 4 (profound signs of infection resulting in removal of the implant).Holgers et al.: Soft tissue reactions around percutaneous implants: A clinical study of soft tissue reactions around skin-penetrating titanium implants for bone anchored hearing aids. Am J Otol. 1988, 9: 56- 59.[6]

An exact classification of the preoperative condition is necessary for every case because it determines all of the subsequent surgical steps. The following procedure is outlined in the guidelines: Levels 0-3 indicate Conversion Type 1, Level 4 requires Conversion Type 2. 

Special Consideration in Surgical Planning

Both surgical procedures—Conversion Types 1 and 2—require exact preoperative planning, especially because the BAHA screw results in additional challenges for BCI 602 placement. It is crucial that the area in which the BCI will be placed is not damaged when the incision is made or during explantation of the BAHA. Preoperative visualization using OTOPLAN can offer assistance during planning BONEBRIDGE implantations. Now we will take a closer look at both conversion types.

Conversion Type 1

This procedure is used for grades 0, 1, 2, and 3 on the Holgers scale—when there are no profound signs of infection (Grade 4).

Phase 1: Explantation

Cut a Rhomboid (Limberg) incision as far away as possible from the position where you will later place the BCI. Then remove the BAHA screw. This is especially important when you suspect a bone infection. Tighten and then explant the screw using the appropriate counter torque wrench, forceps, and/or a cutting bur (2, 3, or 4 mm). To have as much control as possible and avoid damage to the dura, be sure to have a clear line of sight to the bone.

Phase 2: Implantation

After a 5-week healing period, BCI 602 can be implanted. The procedure is the same as a conventional BONEBRIDGE implantation—but potentially requires more flexibility when it comes to placement due to previous surgeries. And here an important advantage of the BCI 602 is clear: The implant has a flexible transition between the receiver coil and the transducer that .

Conversion Type 2

This procedure is used when there are clear signs of infection and/or the skin tissue is already dead (Holgers scale Grade 4).

Phase 1: Explantation

Explant BAHA as in Conversion 1—additionally, remove atrophic and poorly circulated skin tissue to achieve good skin vascularity. And this is where there is the most significant difference to Conversion Type 1: Due to the removal of skin, cut a bilobed flap, rotate 45°, and pull into place. It is important that the skin flap is as well-circulated as possible. Using a Z-shaped incision reduces skin tension so it can be sewn up afterward.

Phase 2: Implantation

The healing period is much longer for Type 2—due to the extent of tissue damage, it lasts at least 5 months. Once again, implantation of BCI 602 is done conventionally. But placement may proceed differently than usual due to the past BAHA explantation. And for better preoperative planning, OTOPLAN can help. The horizontal and vertical flexibility of the implant are also advantageous.

Receive More Information

If you would like to know more about these surgical procedures or the BONEBRIDGE bone conduction system, contact your local MED-EL team.[7]