Revolutionary Middle Ear Surgery: An Interview with Prof. Preyer

Professor Serena Preyer, M.D., is a leading expert in the fields of otolaryngology (ENT), head and neck surgery, and facial plastic surgery. Since taking office in 2016 as clinical director at the ViDia Christian Clinics in Karlsruhe, she has not only contributed her vast experience but has also brought together the ear, nose, and throat clinics of two renowned hospitals —the Diakonissenkrankenhaus Rüppurr and the St. Vincentius Clinics—in the “Fan City” of Karlsruhe.

With comprehensive expertise in all areas of otolaryngology and head and neck surgery, Prof. Dr. Preyer has made a name for herself as a clinic director with an international network. Her expertise ranges from the treatment of hearing disorders to complex surgery for head and neck tumors. She relies on interdisciplinary collaboration to ensure her patients always receive the best possible care.

Particularly noteworthy is her focus on hearing disorders of all kinds. Under her leadership, the Karlsruhe Ear Center offers a wide range of treatments for ear conditions. The interdisciplinary team includes experienced ENT physicians, radiologists, audiologists, and other specialists who also treat hearing, language, and speech disorders in children. Prof. Dr. Preyer also places great emphasis on excellence in nursing care.

The highly qualified nursing staff ensures a high standard of care and attracts patients with hearing problems from the region and across Germany. For complex hearing problems, Prof. Dr. Preyer relies on innovative solutions such as implantable hearing systems or cochlear implants to help her patients regain an active social life. She also demonstrates outstanding expertise in the treatment of ear malformations or tumors.

In addition to her specialization in hearing disorders, Prof. Dr. Preyer has extensive experience in treating nasal and sinus problems as well as in head and neck surgery. She successfully performs surgery for various conditions, ranging from thyroid problems to tumors in the larynx and pharynx.

She places a high priority on the plastic and functional reconstruction of the nose following accidents or the removal of tumors. Prof. Dr. Preyer heads the Head and Neck Tumor Center at the Oncology Center of the ViDia Clinics. This ensures individualized treatment in accordance with international standards and provides support to patients even beyond the actual course of therapy.

Prof. Dr. med. Serena Preyer not only studied and earned her doctorate at renowned universities but has also completed numerous research fellowships both in Germany and abroad. This comprehensive expertise and her impressive skills make her a highly respected specialist in her field.

The editorial team of the Leading Medicine Guide wanted to learn more about middle ear surgery and took the opportunity to speak with Prof. Dr. Serena Preyer.

Middle ear surgery is crucial for treating various hearing problems caused by middle ear conditions such as cholesteatoma, tympanic membrane perforations, or otosclerotic changes. Through innovative techniques and minimally invasive procedures, middle ear surgery aims to preserve or restore hearing while minimizing complications. 

The middle ear can be affected by various conditions. 

“One of the most common conditions affecting the middle ear is certainly middle ear effusion, which is a buildup of fluid in the middle ear. This often affects children, but also adults who have an infection in the upper respiratory tract. Generally, a wait-and-see approach is appropriate in these cases at first. However, if the condition becomes chronic, a ventilation tube should be inserted into the eardrum to allow the fluid to drain. If children have had frequent fluid buildup, this can develop into chronic otitis media, which may persist into adulthood. These individuals often have a perforation in the eardrum; they may experience hearing loss or develop a cholesteatoma—a chronic, purulent inflammation of the middle ear accompanied by bone destruction. “In such cases, more extensive surgical procedures are often necessary—for example, to restore the ossicular chain using passive middle ear implants, or to close the eardrum or remove the cholesteatoma,” explains Prof. Dr. Preyer at the beginning of our conversation.

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Middle ear infections (otitis media): These are usually acute infections of the middle ear caused by bacteria or viruses. Surgery is not the first line of treatment in acute cases. However, if recurrent or chronic middle ear infections occur that do not respond to other treatments—such as a cholesteatoma—or if an acute infection leads to complications, surgery may be necessary.

Cholesteatoma: A cholesteatoma is an accumulation of keratinocytes in the middle ear. These cells can erode bone, which can lead to hearing loss and infections in surrounding areas, such as the meninges. Surgical removal is necessary to prevent complications and preserve hearing.

Perforated eardrum: A hole in the eardrum can lead to hearing loss and increase the risk of infections. Small, acute perforations often heal on their own, but larger or recurrent perforations require surgery to repair the eardrum.

Otosclerosis: This is a condition affecting the ossicles, inner ear, and middle ear in which the ossicles stiffen, leading to hearing loss. In many cases, surgery—known as stapes plasty—is an option.

Otobasal fracture: If the middle ear is damaged in a head injury, surgery can restore the ossicular chain and improve hearing.

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The need for surgery depends on the severity of the condition, the associated symptoms, and the response to other treatments. Surgery is considered when other treatments are unsuccessful or when complications arise. An ear, nose, and throat (ENT) specialist should always determine the best treatment option.

Cholesteatomas are abnormal growths or cysts in the ear that most commonly occur in the middle ear and, less frequently, in the external auditory canal. They usually develop as a result of chronic inflammation or an injury to the ear. 

These growths consist of skin flakes or cells that accumulate in the middle ear and can develop into a sac-like structure. “The topic of cholesteatoma is indeed challenging, as cholesteatomas are a hybrid of a tumor and inflammation. Normal skin, structured in layers just like our outer skin, is found in the middle ear. Here, however, flakes cannot be shed, and a tumor-like growth forms as a result. Strictly speaking, however, it is not a tumor, but rather a destructive inflammation similar to the destruction of a tooth caused by tooth decay. The danger here lies in the location of the growth. After all, the ear is situated at the base of the skull, which means the brain is on the other side. The destructive force of the cholesteatoma can also damage the ossicles, causing the patient to become hard of hearing. “If the inner ear is affected, it leads to dizziness and hearing loss; damage to the facial nerve and facial nerve paralysis can also occur,” says Prof. Dr. Preyer at the beginning of our conversation, adding regarding the causes: “On the one hand, the formation of a cholesteatoma can be congenital. Stray skin is present in the middle ear and sits there like a ball of skin. On the other hand, a cholesteatoma can develop due to ventilation problems in the ear. As a result, the eardrum is severely retracted and lies like wallpaper against the opposite wall of the middle ear, which in turn has a rather uneven surface. This surface contains niches and pockets where skin accumulates and skin flakes become trapped, leading to local inflammation and, consequently, bone destruction. Another cause can be a severe accident resulting in traumatic brain injury. This can lead to displacement of the bone in the ear canal, allowing skin to grow from the ear canal into the middle ear.”

It is important that a cholesteatoma be detected and treated early, as left untreated it can lead to serious complications such as infections, hearing loss, and damage to adjacent structures. “If we compare it to a benign acoustic neuroma (a benign tumor on the vestibulocochlear nerve), the latter is less harmful because, unlike a cholesteatoma, it does not cause inflammatory reactions. Inflammation at the base of the skull can subsequently lead, for example, to meningitis or a brain abscess,” emphasizes Prof. Dr. Preyer regarding the effects of a cholesteatoma, and adds further information about the patients’ symptoms: “A congenital cholesteatoma does not cause the patient any pain. The patient is more likely to experience early-stage hearing loss or facial nerve paralysis. A ‘normal’ cholesteatoma manifests as painless ear discharge—which often has a very foul odor—and hearing loss. If these symptoms are present, the patient should definitely see an ear, nose, and throat (ENT) specialist first—ideally one with experience in ear surgery—who will examine the ear using an otoscope. A cholesteatoma could sometimes be overlooked when using an otoscope. Fortunately, cholesteatoma is quite rare—it affects approximately 3 out of 100,000 children and 9 out of 100,000 adults in the European population.”

Eardrum perforations can result from a variety of causes.

A perforated eardrum, or a hole in the eardrum, is a medical condition in which the eardrum is partially or completely missing. This opening can be caused by various factors, such as infections, trauma, changes in pressure, or brief exposure to very loud noises. The effects of a perforated eardrum can range from mild symptoms such as ear pain and ringing in the ears to hearing loss and recurrent infections. The diagnosis and treatment of a perforated eardrum require a careful evaluation by an ear, nose, and throat (ENT) specialist to prevent potential complications and preserve hearing.

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The eardrum, also known as the tympanic membrane, is a thin membrane between the ear canal and the middle ear that plays a crucial role in transmitting sound waves from the outer ear to the middle ear. A perforation or tear in the eardrum can occur for various reasons, affects hearing, and can trigger recurrent middle ear infections.

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“If you ask an ear surgeon, there are two major forms of chronic middle ear inflammation—first, cholesteatoma, or bone abscess, and second, chronic mucosal inflammation, which is primarily characterized by a hole in the eardrum. Even with a perforated eardrum, the ear may drain when it is acutely inflamed, and clear or purulent discharge may flow from the ear. In this case, the patient would be advised to have the perforation surgically closed so that the ear stops draining and to prevent hearing loss in the long term. This is because if a perforated eardrum is not closed, a cholesteatoma may develop over a period of years. As for the recommendation for surgery, a cholesteatoma is an absolute indication for surgery. Surgery to close a hole in the eardrum is an “optional procedure” that is recommended, especially if the patient is still young. For patients with ear conditions who also have other medical conditions and for whom surgery would place too great a physical strain on the body, surgery would generally be avoided. In such cases, the perforation of the eardrum would be monitored and checked once a year. “And if it turns out at some point that there is indeed an imminent risk, surgery can still be performed,” explains Prof. Dr. Preyer.

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• Fresh perforations sometimes heal on their own. The doctor can monitor the healing process. The ear should be protected from water or dirt to support healing.
• In cases of larger or persistent perforations, surgery may be necessary to repair the eardrum. In tympanoplasty, the patient’s own tissue—such as muscle fascia or cartilage—is used to close the hole and restore normal eardrum function. Depending on the findings, the procedure is performed on an outpatient or inpatient basis and requires specialized follow-up care.
• For smaller, recent perforations, the doctor may place a splint over the hole to close the eardrum and promote healing.

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Regarding surgery for a perforated eardrum, Prof. Dr. Preyer notes: “As a rule, ear surgery to repair a hole in the eardrum is complex, simply because the ear has a complicated structure. There are many important structures in the middle ear: the vestibular system, the cochlea, the facial nerve that runs through the ear, and the vagus nerve. These are all structures that one absolutely does not want to damage. For this reason, ear surgeons must undergo extensive training. These surgeries are usually performed under a microscope, especially when a significant amount of bone needs to be removed. This is the case, for example, with surgery for a cholesteatoma, and then—just as a dentist drills out a decayed tooth—the ear surgeon must drill out the ear until it is completely clean. In the second step, the ear is then reconstructed so that it functions properly again. “So first, bone is removed, and then the ear is reconstructed,” she explains. Regarding the duration of the surgery, the ear specialist adds: “The duration of the procedure varies greatly. Sometimes it takes half an hour; in other extreme cases—such as when there is an extensive cholesteatoma—the surgery can sometimes take as long as six hours, especially if the cholesteatoma has already grown toward the brain.”

There are two types of hearing loss: inner ear hearing loss and middle ear hearing loss.

“Inner ear hearing loss” occurs when the inner ear or the auditory nerve is damaged. This can be caused by various factors, including genetic predisposition, aging, noise exposure, certain medications, infections, or diseases such as Meniere’s disease (a chronic disorder of the inner ear). Symptoms of inner-ear hearing loss may include hearing loss, difficulty hearing certain frequencies, tinnitus, and problems understanding speech in noisy environments. Middle ear hearing loss, on the other hand, occurs when there are problems with sound transmission from the outer to the inner ear, typically due to a blockage or a problem with the middle ear structures, such as the eardrum or the ossicles. 

“In chronic otitis media, recurrent inflammation can destroy the ossicles, but toxins produced by the bacteria can also lead to inner ear hearing loss. People who have had chronic otitis media for many years therefore generally have mixed hearing loss. The damage affecting the ossicles can be compensated for quite well with titanium implants. And when the eardrum vibrates, the vibration can be transmitted to the inner ear via the implants. Inner-ear hearing loss, on the other hand, cannot be compensated for with a passive implant, since the inner ear itself acts as an active amplifier that consumes energy,” explains Prof. Dr. Preyer.

A cochlear implant is often used to treat severe to profound hearing loss, which can be caused by various diseases or conditions. 

“If you want to compensate for inner-ear hearing loss, you have to introduce energy into the system, which is done in the form of a conventional hearing aid, an active middle-ear implant, or a cochlear implant. Cochlear implants have been around for about 50 years. In the past, these implants were used exclusively for people who were completely deaf. In the meantime, the digital revolution has also contributed to the development of cochlear implants, which have improved enormously in technical terms over the past few decades. As a result, the indication for a cochlear implant is now established much earlier, for example, even in cases of unilateral deafness. “If both ears are affected and speech comprehension is no longer 60% or higher with optimal hearing aid fitting, then cochlear implant surgery is recommended today,” says Prof. Dr. Preyer regarding the use of a cochlear implant.

A cochlear implant is a highly sophisticated medical device that helps people with severe to profound hearing loss or deafness hear better again. Unlike hearing aids, which merely amplify sound, a cochlear implant works in a completely different way. The device converts sound signals directly into electrical signals that stimulate the auditory nerves and can then be interpreted by the brain. It consists of two main components: an external one and an internal one. The external component includes a microphone, a speech processor, and a transmission coil. The microphone picks up sound signals from the environment and transmits them to the speech processor. There, the sound signals are converted into digital signals and sent via the transmitter coil to the internal component of the cochlear implant. The internal component is surgically implanted and consists of a receiver coil, a stimulator, and an electrode. The receiver receives the digital signals from the external transmitter coil and forwards them to the stimulator. The stimulator sends electrical impulses to the electrodes, which are placed along the length of the cochlea. These electrodes stimulate the auditory nerve fibers in the inner ear, which the brain perceives as sound. In this way, the cochlear implant enables users to hear again by mimicking the natural function of the inner ear and converting sound signals into electrical impulses that the brain can interpret.

For some patients, it may seem strange to have a hearing device anchored inside the skull so that the cochlear implant’s receiver coil can be attached. “Patients react very differently to this option. Many are simply happy that they can hear something again. However, it’s important to note that we normally hear mechanically, which isn’t the case with this implant—here, the person hears electrically, since the mechanical vibration is converted into an electrical signal. So hearing is quite different. The auditory experience is electrical. Patients describe the sound at first as sounding a bit like Mickey Mouse—that is, like a cartoon voice—because there aren’t as many overtones,” explains Prof. Dr. Preyer, but he also outlines upcoming improvements: “Manufacturers are working intensively on improvements, and an incredible amount has been achieved in recent years, so that people with a cochlear implant not only regain their ability to understand speech but can also hear and enjoy music again.”

After a cochlear implant is inserted, a certain amount of time is needed for healing and adjustment. “Since this is a surgical procedure, the site where the implant was placed must first heal. After 1–6 weeks, the initial fitting can take place; that is, the patient returns to the center where the implantation was performed, and the initial settings are adjusted. Here, the level of electrical current is adjusted (the correct amplitude is selected, as the current must not be too high or too low). Eventually, the patient’s brain learns to process these signals, which is a lengthy process. The device is readjusted at regular intervals, as it must be adapted to the new situation—a task performed by audiologists. The implant recipient gradually learns to hear better. This process takes 1–2 years until stable hearing is established. Follow-up visits are then scheduled at least once a year for the rest of the patient’s life,” says Prof. Dr. Preyer, describing the period following cochlear implant surgery.

In middle ear surgery, there are ongoing research efforts and developments aimed at shortening the postoperative recovery period and improving treatment outcomes. 

When asked what’s currently happening in middle ear surgery and what her hopes and dreams are as an ear surgeon, Prof. Preyer replies:

“We’re working to make ear surgeries increasingly minimally invasive. Minimally invasive middle ear procedures can already be performed through the ear canal today. Here at the clinic in Karlsruhe, we were one of the first clinics in Germany to perform endoscopic ear surgery. This technique will certainly continue to improve and become more widespread in the near future, and it will become increasingly rare to have to make an incision behind the ear. The positive side effect for patients is that they experience less postoperative pain, as there is less damage to soft tissues. To reduce the recurrence rate after cholesteatoma surgery, it would be desirable to use chemical treatments in addition to the surgical procedure. This is already partially feasible today, and certain substances can help dislodge a cholesteatoma more effectively. However, the method is not yet fully developed. And with cochlear implants, it would be wonderful if patients could achieve even better hearing quality for speech—but also for music—even in noisy environments. Of course, it would be an absolute dream if we could administer medications into the middle ear that would then travel to the inner ear to repair damaged areas there. “That would be a huge leap forward in our field,” emphasizes Prof. Dr. Preyer, and with that, we conclude our conversation on a hopeful note.

Thank you very much, Professor Dr. Preyer, for this insightful conversation about the complexities of ear surgery!