Perilymphatic fistula

What Is a Perilymphatic Fistula?

A perilymphatic fistula (PLF) is a small, abnormal opening between the inner ear and the middle ear. The inner ear is an organ completely contained within a bony capsule and filled with a special fluid called perilymph, which plays an essential role in both hearing and balance. In that bony capsule of the cochlea (the inner ear), there are two openings, called windows: the oval window and the round window. These are the weakest points of the inner ear. When the perilymph fluid leaks into the middle ear—usually through a small tear or defect at one of the two thin membranes that separate these spaces, the oval window or round window—the normal pressure balance in the inner ear is disrupted.

To make the term clearer:
A fistula is simply an abnormal connection between two parts of the body that shouldn’t normally communicate. Think of it like a tiny leak in a sealed system—once the leak forms, the system stops working properly.

---

Understanding the Pathophysiology

(How and Why a Fistula Forms)

There are several ways that can lead to the formation of a PLF, and they all revolve around stress or injury to the delicate membranes separating the inner and middle ear.

1. Traumatic Causes

A significant blow to the head, especially around the ear or side of the skull, can cause a tear in the oval or round window. Even without a direct hit to the ear, the sudden pressure wave created by trauma can injure the membrane.

2. Pressure-Related (Barotrauma) Causes

A sudden change in pressure can overwhelm the inner ear’s ability to equalize. This can happen during:

• Scuba diving

• Airplane travel

• Forceful nose-blowing

• Heavy lifting or straining (the Valsalva maneuver)

• Severe coughing or sneezing spells

The pressure difference may stretch or rupture the membrane, creating a leak.

3. Iatrogenic Causes (Medical or Surgical)

Certain ear surgeries, such as stapedectomy (a surgery for otosclerosis), cochlear implantation, or middle-ear procedures, may weaken or disrupt the windows between the middle and inner ear.

4. Congenital Causes (Present at Birth)

Some individuals may be born with weaker membranes or tiny pre-existing openings that become symptomatic later in life with minor triggers.

5. Spontaneous PLF

In some cases, no clear trigger is found. These spontaneous fistulas may occur because of subtle congenital weaknesses or everyday pressure changes that finally exceed the membrane’s resistance. The existence of truly spontaneous PLF remains debated among experts.

---

Clinical Presentation

What Symptoms Does a PLF Cause?

Because the inner ear controls both hearing and balance, a PLF can affect one or both of these systems. The symptoms can be sudden or gradually progressive.

Common symptoms include:

• Sudden or fluctuating hearing loss, often in one ear

• Episodic dizziness or vertigo, especially triggered by straining, lifting, or pressure changes

• Imbalance, unsteadiness, or a “floating” sensation

• Tinnitus (ringing or buzzing in the ear)

• A feeling of fullness or pressure in the affected ear

• Sensitivity to loud sounds, which may trigger dizziness (called Tullio phenomenon)

Some people notice that symptoms are much worse during activities involving pressure shifts, such as going up an elevator, blowing their nose, or even laughing hard.

---

The Medical Work-Up

How ENT Specialists Evaluate a Suspected PLF

Taking a Detailed History

The first step is understanding what the patient experienced. Key questions include:

• Did symptoms start suddenly, especially after trauma or pressure changes?

• Do dizziness or hearing changes fluctuate with physical activity?

• Are there activities that reliably trigger symptoms (lifting, air travel, nose-blowing)?

• Has there been any recent ear surgery?

* Because PLF often mimics other disorders like Ménière’s disease or vestibular migraine, this part of the evaluation is crucial.

Physical Examination
On exam, the eardrum usually appears normal. However, the ENT specialist might trigger eye movements (nystagmus) with certain pressure maneuvers, such as pushing gently on the tragus (the small flap in front of the ear canal), with pneumatic otoscopy (creating small pressure changes in the ear canal), or by asking the patient to perform a Valsalva maneuvre (pinching your nostrils and blowing air into your ears). These tests can indirectly reveal a pressure-sensitive inner ear.

Hearing Tests (Audiometry)
Audiograms often show sensorineural hearing loss, which may fluctuate. A normal hearing test does not rule out a PLF however. To learn more about audiograms, you can read this article.

Vestibular Testing
Tests like VNG (videonystagmography) may show abnormalities, especially if symptoms worsen with pressure changes or certain sound frequencies. You can learn more about VNGs in this article. A vHIT can also be done to evaluate weakness in the balance function in the affected ear. Learn more about vHIT here.

Imaging
CT scans of the temporal bone may show structural issues (such as congenital abnormalities), but they rarely show the fistula directly. MRI may help rule out other inner-ear causes. Unfortunately, no current imaging test can reliably confirm a PLF.

Exploratory Surgery
In very suspicious cases, especially when symptoms are disabling or hearing is deteriorating, the ENT surgeon may recommend exploratory tympanotomy. This allows direct visualization and repair of the suspected leak.

---

Treatment Options

Conservative (Non-Surgical) Management

Many PLFs can heal on their own if the inner ear is given enough time and rest. Conservative treatment often includes:

• Avoiding heavy lifting, straining, or nose-blowing

• Bed rest or reduced activity

• Avoiding air travel or diving

• Sometimes a short period away from work if symptoms are severe

This approach is often tried first, especially when symptoms are mild.

Surgical Repair

If symptoms do not improve with conservative treatment, or if the hearing loss or dizziness is significant, surgery may be recommended. The operation is done through the ear canal under a microscope, under local anesthesia (the patient is awake).

The surgeon places a small graft (often fibrous tissue like perichondrium) over the oval and/or round window to seal the leak and reinforce the membranes. Recovery typically involves several weeks of avoiding pressure-inducing activities.

Most patients experience improvement in dizziness relatively quickly, while hearing recovery is more variable.

---

Living With a Perilymphatic Fistula

Living with a PLF can be frustrating because the symptoms often worsen with routine activities that change pressure—standing up quickly, lifting a child, even laughing or coughing. Many patients learn to modify their daily habits to avoid symptom triggers.

Some individuals may become anxious about worsening their symptoms, especially before diagnosis. Balance problems can impact work, sports, and social life. The uncertainty of hearing changes—especially if fluctuating—can also be stressful.

The good news is that with correct diagnosis and a proper treatment plan, most patients experience meaningful improvement. Dizziness usually responds best to treatment, while hearing recovery can vary. Many patients can return to their normal activities after the leak has been repaired or stabilized.

Regular follow-up with an ENT specialist is important, especially if symptoms recur or if new hearing changes develop.