Minimally-Invasive Bone-Anchored Hearing Aid Screw Surgery Increases Tissue Preservation for Better Patient Outcomes

“On day one of medical school we learned that you have to respect the tissue.”
~
Daniel Coelho MD

British BAHA patient 15 hours post-surgery. Note the very long scar and bruising of the skin flap because the consultant used poor surgical techniques.

During our 1½ day training session at Oticon USA’s headquarters last week, we were made aware of their excellent article on tissue preservation using a minimally-invasive surgical procedure to implant the screw for bone-anchored hearing aid (BAHA) devices using a dermatology biopsy punch, developed by Prof Daniel Coelho MD at Virginia Commonwealth U in Richmond. Given the number of photos we’ve seen of BAHA recipients who have been painfully butchered while under general anesthesia to install the screw, Dr Coelho’s clever method reduces this to just a 10 minute in-office procedure performed under a local anesthetic, with the bonus of reduced risk of infection. Because we believe this vastly improved procedure will expand the universe of candidates who have microtia/atresia, single-sided deafness (SSD), and severe conductive losses, at their request we are reprinting it, adding in our own comments and photos as well as this lede. If you are a BAHA candidate we recommend printing this article and discussing this with your surgeon.

Here is the article:
Progressive surgeons like Dr. Coelho spend a great deal of their time studying outcomes and working together to improve surgical procedures. Yet, very few patients are aware of the surgical implant techniques used for bone anchored hearing devices. Many only know of the traditional skin-graft technique, which causes a visible scar and frequently results in skin overgrowth and post-surgical irritation. Today, we’re sharing information about a new technique that Dr. Coelho uses. It’s a minimally invasive technique to optimize tissue preservation.

Photo courtesy of Oticon Medical

Photo courtesy of Oticon Medical
Click to enlarge in a new window

The procedure takes about 10 minutes and is typically done under local anesthesia. As most users have experienced, patients can expect a bit of soreness for a few days afterward. But, with little pain and no narcotics, patients can go back to work or normal routines the day after the procedure. This is all because the whole process is designed with tissue preservation in mind.

Tissue preservation is important for several reasons. It contributes to a very short amount of recovery time, and there’s little -to-no scaring and no hair removal. The bottom line is that the tissue preservation is minimally invasive, which improves overall results.

The fact that the procedure is minimally invasive is the most important aspect of a surgical procedure. “The more trauma there is, the more inflammation and scarring. While scarring isn’t ideal cosmetically, it also means less predictable tissue – the implant and the abutment are foreign objects that the tissue can work to reject,” Dr. Coelho explained.

It's easy to preserve tissue when you use the right tool, such as a dermatology biopsy punch instead of going hog-wild with a scalpel.

It’s easy to preserve tissue when you use the right tool, such as a dermatology biopsy punch instead of going hog-wild with a scalpel.

Tissue preservation is incredibly important in function—it’s one of the most important aspects of the surgery. And it’s all possible since the introduction of longer abutments. “The Ponto is an excellent product and a major advancement was the development of the longer abutment. With a longer abutment, it’s no longer necessary to thin out the tissue to prevent the processor from touching the skin. If you’re going to be doing tissue thinning and suturing, those are traumatic to the skin and soft tissue and may result in an increased inflammation. Inflammation can lead to scarring, tissue overgrowth, loss of sound quality and eventually to non-use.” As an added benefit, less tissue inflammation also yields excellent cosmetic outcomes. [Link opens a PDF in a new window: Ed.]

In the 70-80’s, an abutment was 5 mm or less. “The only way to get the processors to function without rubbing against the skin (and compromising sound quality) was by undermining the skin” Dr. Coelho recalls. “Once the new, longer abutment came out, and the sound quality was shown to be equal, it showed that any additional skin manipulation was not necessary.” Oticon Medical was a leader in introducing the longer abutments, giving surgeons increased flexibility to adapt to individual variations in skin thickness and accommodating new clinical developments in surgical techniques, including tissue preservation.

The improved technology enables medical providers to focus on other factors like continuously iterating surgery to be as minimally invasive as possible. “Patients are happy with the functionality and the great cosmetic outcomes — it’s truly as minimally invasive as you can get.”

Melissa Tumblin, founder of Ear Community [microtia/atresia support group: Ed.] asked Dr. Coelho, “What are the common concerns about skin irritation? What do you recommend other than the cortisone cream and general cleanly maintenance?”

Photo courtesy of Oticon Medical

Photo courtesy of Oticon Medical
Click to enlarge in a new window

“First of all, hygiene shouldn’t be blamed for everything. Some people just have a more robust reaction to that foreign object—just like people have allergies worse than others.” Dr. Coelho explains that some people even clean too frequently, which can irritate the area even more.

Dr. Coelho has had no skin overgrowth, as of 2-year follow-ups, with his own patients that received their implant via the [dermatology biopsy: Ed.] punch technique. When he does treat overgrowth, it’s in patients who had the traditional technique. For overgrowth, Dr. Coelho uses clobetasol cream, a topical steroid to help reduce the number of surgical revisions. But, he points out that there is a longer term solution. “Surgical revisions only buy time, they do not actually fix the underlying problem. But, the longer abutments theoretically do. Because it’s such a simple procedure to switch, people who were getting the steroid shots are now making the change. The abutment change procedure is done in the office and takes seconds—some insurance companies are covering the abutment switch.” Patients can also immediately go back to wearing their processor unlike some of the corrective treatments.

Overall, more surgeons are slowly, yet surely, implementing the minimally invasive procedure. Dr. Coelho predicts that within 5 years it will be the standard. “Surgeons learn from colleagues, conferences, journals and the industry as well. People expect to see a divide between industry and medical providers, but many technological advances are made by industry organizations or through a collaboration with clinical professionals – this open line of communication benefits everyone.”

References:

  1. Bone Anchored Hearing Aid. August 27th, 2013: Oticon Medical, author not listed.

Bootnotes:

Daniel H Coelho MD FACS specializes in Otologic & Neurotologic Surgery. He is assistant professor of Otolaryngology, Physiology and Biophysics, and he’s the director at the Cochlear Implant Center at Virginia Commonwealth University School of Medicine in Richmond, Virginia. Following his training in Otolaryngology, Dr. Daniel Coelho completed a two-year fellowship in skull-base surgery. He began practicing minimally invasive linear surgery 5 years ago, and was an early developer of the punch method about two years ago.

► Astute readers will notice we did not endorse either Cochlear’s, Sophono’s, or Oticon Medical’s BAHA devices and attachment methods, as each has advantages & disadvantages over each other. We have received numerous user reports that the Oticon Medical Ponto devices have better sound quality than the corresponding Cochlear BAHA’s (probably due to their “Speech Guard” (PDF) processing for speech envelope preservation, which we liked in our listen-testing to the Alta2 Pro-100 BTE’s); however Cochlear now has available the “BAHA attract” way (copied from Sophono) to magnetically attach the device to the scalp, similar to the way a CI coil works. It appears that a compromise must be made when selecting the attachment method, as the sound quality seems to be better when the inertial transducer is directly coupled to the abutment, as opposed to the vibrations being transmitted through the skin. On The Other Hand, according to FDA MAUDE data approximately 4% of BAHA screws are spontaneously extruded.

► Also, we would be remiss to overlook wireless connectivity: As we reported almost three years ago years ago, Cochlear licensed GN ReSound’s 2.45 gHz low-latency digital transmission and Bluetooth 4.0 Low Energy technology, with their BP400 supporting first and second generation Unite peripherals, and the new “Made for iPhone” (MFI) BP-500 supporting the second generation of peripherals and also direct connectivity with their version of the SMART app to the iPhone 5 & up and Apple Watch. The list of which Unite accessories work with which Cochlear devices can be found here (use the LiNX & Enzo column for BP-500 compatibility).

Although the Oticon Ponto apparently has a sound quality advantage, the same cannot be said for its’ wireless connectivity, as their Streamer is required, even for FM. What’s more, users who have an Oticon hearing aid on the other ear cannot share the same streamer, as the hearing aid and BAHA versions are Not Compatible. What’s more, wearing one of each streamer won’t work, as at present a mobile phone will only route Bluetooth audio to one destination at a time. Worse, the Ponto line lacks the 3-pin “Euro” direct audio input (DAI)  socket to use micro-sized Roger or even their own Amigo FM receivers: To use any FM the user must wear the Streamer on a lanyard, which can be troublesome for a child; and as we’ve previously written, all hearing impaired children should use this powerful weapon.

Boiling it all down, audiologically the Ponto devices are better; however for children unable or unwilling to wear the Streamer to access the tremendous signal-to-noise benefits delivered by FM (or even better, using Phonak Roger digital transmission), then the Cochlear BP400 or BP500 with the ReSound Mini Mic should be chosen.

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About the author

Dan Schwartz

Electrical Engineer, via Georgia Tech

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