Intratympanic Microwick Placement (Microwick Placement)

Overview of Intratympanic Microwick Placement

Neurotology is a field of medicine focused on disorders of the inner ear, like hearing loss, vertigo (a dizzy sensation), and tinnitus (ringing in the ears). Many people experience these conditions, and treating them can be a bit tricky. Most of the time, regular medications don’t reach the inner ear in strong enough doses to effectively treat these disorders.

So, how do doctors handle this? They use special procedures called intratympanic injections and tympanostomy tubes. These techniques allow medicines to be delivered directly to the hard-to-reach parts of the inner ear. Doctors use these treatments for conditions like sudden hearing loss with no known cause (also called ‘idiopathic sudden sensorineural hearing loss’), Ménière’s disease (which causes vertigo), and autoimmune inner ear disease (a disorder in which the body’s immune system attacks the inner ear).

Another clever tool used by doctors is the MicroWick. Inserting this tiny wick into the ear lets medication be absorbed and spread directly to the inner ear’s round window membrane and perilymph, which are important parts needed for hearing and balance.

Anatomy and Physiology of Intratympanic Microwick Placement

The ear is typically divided into three parts: the outer, middle, and inner ear, with each part carrying out an important role in enabling us to hear sounds. The outer ear includes the part of the ear that you can see, the ear canal and the eardrum. The eardrum, or tympanic membrane, separates the outer ear from the middle ear. Inside the middle ear, there are small structures known as ossicles which help to transmit sound from the eardrum.

Sound waves move from the outer ear to the eardrum and then begin to vibrate with a part of the ossicles known as the malleus. The vibrations move down the chain of ossicles, from the malleus to the incus and then to the stapes. Finally, the stapes connects with the cochlea, a part of the inner ear, at a point called the oval window. The movements at the oval window send vibrations into a fluid within the inner ear. These vibrations eventually end up at another structure known as the round window, which helps to control the vibrations and make the overall sound clearer.

The round window, located behind and to the inside of the oval window, measures around 1.5 to 2.1 mm horizontally, 1.9 mm vertically, and is 0.7 mm thick. The round window may look oval, skewed, or non-flat. It can be found approximately 3.44 mm behind the umbo of the malleus, a part of the ear ossicles, and at an angle of about 113° from the long process of the malleus. There is a membrane at the round window that separates the inner ear from the middle ear space.

This membrane at the round window consists of three layers: an outer ear layer, an inner ear layer, and a layer of connective tissue in between. A thin, bony overhang called the round window niche often covers up the membrane, making direct access to the fluid of the inner ear challenging. In some cases, a thin layer of tissue that obstructs the view of the round window membrane can also be present.

The outer layer of this membrane at the round window decides how permeable, or able to let substances through, it is. This outer layer is made up of cells linked by gap junctions, allowing for the transport of molecules. These features make the round window membrane partially permeable, meaning it can let through substances such as antibiotics, toxins, and local anesthetics. However, the ability of a substance to cross this membrane depends on the thickness of the membrane and the concentration, size, and charge of the molecules. Once molecules cross this membrane, they are absorbed into the fluid within the inner ear. However, if there is local inflammation like an ear infection, it can reduce the permeability of the round window membrane.

Why do People Need Intratympanic Microwick Placement

If you have certain illnesses, your doctor may consider a treatment that involves putting medicine directly into your ear. This happens through an injection or by placing a small piece of absorbent material, known as a “MicroWick”, into your ear. This method can be helpful for a variety of conditions, including:

1. Idiopathic sudden sensorineural hearing loss (ISSNHL), which is a sudden loss of hearing that doctors aren’t sure of the cause. This can be a primary treatment or a backup plan if other therapies aren’t working.
2. Ménière disease (MD), a disorder that affects your inner ear and can cause dizzy spells (vertigo) or hearing loss.
3. Autoimmune inner ear disease (AIED), a condition where your body’s immune system mistakenly targets your inner ear, leading to hearing loss.

Also, if it’s hard for you to travel to the clinic for several ear injections, your doctor may use the MicroWick method. The MicroWick lets you take care of yourself at home by putting ear drops in your ear for a set time period. This type of treatment also helps to avoid side effects related to taking medicines by mouth or injection into veins or muscles (systemic administration).

When a Person Should Avoid Intratympanic Microwick Placement

There are a few reasons why a MicroWick™, a tiny device that’s inserted in the ear, can’t be put in place. These include:

• If a person is unable or not willing to undergo a simple procedure done at the doctor’s office.
• If there are unusual growths in the middle ear, like glomus tumors or cholesteatomas, which are skin growths that don’t belong there.
• If there are abnormal blood vessels, like an off-course internal carotid artery that usually supplies the brain with blood or a high-riding jugular bulb, which is a vein that can sometimes enlarge and press on your ear.
• If the round window membrane, an important part of your ear, is blocked and can’t be accessed.
• If the view of the tympanic membrane (the eardrum) and middle ear space is obstructed, making it hard for the doctor to see properly during the procedure.

Equipment used for Intratympanic Microwick Placement

To carry out a procedure that involves placing a small device known as a MicroWick™ inside your ear (a procedure known as an intratympanic MicroWick™ placement), the doctor typically requires certain equipment. Let’s break them down into simpler terms:

• Binocular operating microscope: A special microscope that doctors use to see very small areas clearly during the procedure.
• 30-degree endoscope (optional): An instrument with a light and a camera that helps doctors see inside your ear.
• Operating ear speculum: This is a tool that helps open your ear, making it easier to perform the procedure.
• Otolaryngology examination chair: A particular chair where you’ll sit during the procedure, specially designed for ear, nose, and throat examinations.
• Local anesthetics such as Phenol, 10% lidocaine topical, or 1% lidocaine with 1:100,000 epinephrine: These medicines will help to make the ear area numb and reduce any pain during the procedure.
• Loop curette, Earpick, Myringotomy knife or CO2 laser: These are all instruments doctors use to help in the procedure, from cleaning the ear to making cuts if needed.
• Frasier suction instruments: A tool used to suction or remove fluid from your ear during the procedure.
• Alligator forceps, Cup forceps: Types of forceps (similar to tweezers) that doctors use to hold or move small objects.
• Tympanostomy tube with a 1.42 mm inner diameter and 3.25 mm flange: This is a small tube that may be placed in your ear during the procedure.
• 1 x 9-mm polyvinyl acetate MicroWick™: This is the tiny device that gets inserted into your ear.
• Otic medications such as dexamethasone solution, prednisone solution, methylprednisolone solution, or gentamicin solution: These are medications that your doctor may use in your ear during or after the procedure.

Who is needed to perform Intratympanic Microwick Placement?

The placement of an Intratympanic MicroWick, a tiny medical device used in ear treatments, is usually done by a special type of doctor known as an otolaryngologist. These are doctors who have special training to handle ear, nose, and throat problems. The otolaryngologist doesn’t do this alone, they usually have help from a nurse or a medical assistant. These are medical professionals who assist doctors during procedures.

Preparing for Intratympanic Microwick Placement

Before any medical procedure, the doctor will have a detailed conversation with the patient. They will discuss the positives and negatives of the operation, any different treatment options that might be available, and what exactly the procedure will involve. This is all part of the process of obtaining ‘informed consent’, whereby the patient understands all these factors and agrees to the procedure. It’s a crucial step to ensure that patients are fully aware of what is happening to them and why.

How is Intratympanic Microwick Placement performed

MicroWick insertion in the ear is a procedure that’s done in the doctor’s office, with the patient reclined and the ear that’s being treated facing upwards. Anything blocking the ear (like ear wax) needs to be removed first so that the doctor can clearly see the eardrum and the structures of the middle ear.

Once the ear is clear, the doctor will use a local anesthetic on a specific part of the eardrum. The doctor makes a small cut (known as a myringotomy) in the eardrum near a part of the ear called the round window niche. The cut can be made with a knife or a laser, but the laser might be preferable because it can reduce bleeding during the procedure.

To see the structures of the middle ear, the doctor uses a special microscope or an endoscope, which is a thin tube with a light and camera. If there’s anything else blocking access to the round window membrane – a thin membrane in the ear – the doctor will remove it. The doctor will then insert a small tube (tympanostomy) in the eardrum. They will use certain parts of the ear to guide the positioning and then slide the MicroWick through the small tube to make contact with the round window membrane.

Once the MicroWick is correctly positioned, the doctor will put the necessary medicines in the ear or inject them directly into the MicroWick. The MicroWick will then expand as it absorbs the medication, securing it within the tympanostomy tube.

The patient is then asked to sit in the operating chair and relax. This allows any dizziness caused by the procedure to pass. Importantly, the MicroWick has to be removed or replaced within four weeks to avoid it sticking to the round window niche. To remove the MicroWick, the doctor will use a small pick.

Possible Complications of Intratympanic Microwick Placement

Putting in a small tube called a MicroWick into a part of the ear called the tympanum is generally a safe medical procedure. However, it doesn’t come without potential issues or side effects. Doctors usually recommend using antibiotic ear drops at the same time as the treatment to lower the risk of infection. After the procedure, patients might feel pain or pressure at the site where the MicroWick was inserted or they might feel a bit dizzy for a short time.

There are other risks that may happen from placing the MicroWick including:

• Middle ear and outer ear infections
• Development of a cholesteatoma, which is a noncancerous skin growth that can develop in the middle part of the ear behind the eardrum
• Hearing loss
• MicroWick sticking to a small part of the ear called the round window niche
• MicroWick getting lost or broken in the middle part of the ear
• A hole in the eardrum that doesn’t heal
• The MicroWick coming out on its own
• Feeling dizzy, usually for a short time
• Possible injury to nearby structures like the small bones in the ear or the facial nerve.

Despite these potential risks, this treatment is generally considered safe and effective.

What Else Should I Know About Intratympanic Microwick Placement?

The MicroWick, a tool used by ear, nose, and throat doctors, is a new way to deliver medication directly to the inner ear, specifically to the round window membrane, which is a thin part of the ear deep inside. This tool allows for more efficient treatment of inner ear diseases.

Instead of taking medication by mouth, which could have side effects throughout your body, the MicroWick allows for direct delivery of medication to your inner ear. This enables higher amounts of the drug to work exactly where it is needed and helps avoid unwanted side effects elsewhere in the body.

Studies have shown that the MicroWick system has been successful in treating issues such as Ménière’s disease, a condition that can cause vertigo or a sense of spinning. In one study, this treatment reduced vertigo symptoms in more than three-fourths of patients. Furthermore, injecting a medicine called methylprednisolone through the MicroWick successfully restored hearing in two-thirds of patients needing fallback treatment for sudden sensorineural hearing loss (a rapid loss of hearing).

Placing a MicroWick inside the ear is a simple procedure that can be done in a doctor’s office using numbing medicine. It not only reduces healthcare costs but also lessens illnesses from various ear and nerve-related conditions. It’s especially beneficial because it reduces travel times and visits to the doctor, and overall discomfort in patients compared to traditional injection methods. This makes the MicroWick a potential treatment option for many patients dealing with diseases of the inner ear.