The Eustachian tube functions to regulate middle ear pressure, drain middle ear secretions into the nasopharynx, and protect the middle ear from sound pressure and build-up of nasopharyngeal secretions. Its function stems from a valve-like region created by the insertion of the tensor veli palatini muscle, distal to the nasopharyngeal orifice. The contraction of the tensor veli palatini initiates the opening of the Eustachian tube via a concerted action with other peri-tubal muscles, regulating the ventilation of the middle ear.

Due to its role in pressure equalization, inadequate function (dysfunction) of the Eustachian tube can result in symptoms such as tinnitus, dizziness, clicking sounds, hearing problems, and fullness of the ear. Eustachian tube dysfunction (ETD) is grouped into three main categories: (1) dilatory ETD, which occurs when obstruction of the valve-like region causes chronic negative pressure and eventual effusion in the middle ear due to the failure of the valve to appropriately open the Eustachian tube ; (2) baro-challenge ETD, which occurs when the Eustachian tube does not adequately regulate acute pressure changes; and (3) patulous ETD, which is when the inability of the Eustachian tube to close causes increased perception of one’s bodily sounds, including autophony. Balloon Dilation of the Eustachian Tube (BDET), first performed by Ockerman et al. in 2009, has since demonstrated effectiveness in multiple randomized controlled trials. It addresses both dilatory and baro-challenge ETD and is the only FDA-approved treatment for Eustachian tube dysfunction.

According to work by Poe et al., the most common cause of dilatory and baro-challenge ETD is mucosal inflammation within the cartilaginous portion of the Eustachian tube, reducing ventilation of the middle ear and resulting in chronic negative pressure. Common symptoms include aural fullness, otalgia, and serous otitis media, which can lead to complications such as atelectasis, retraction pockets, and cholesteatoma.

ETD usually presents with aural fullness or hearing loss secondary to decreased ventilation of the middle ear and is often caused by a combination of inflammatory factors (e.g., allergic rhinitis, chronic rhinosinusitis, laryngopharyngeal reflux, and adenoid hypertrophy). All contributing factors must be considered and addressed when managing ETD ( Fig. 54.1 ). It is also important to evaluate for alternate pathologies that might mimic the symptoms of ETD, including cochlear hydrops, superior canal dehiscence, chronic barosinusitis, and temporomandibular joint disorders, as empirically, dilating the Eustachian tube inappropriately can lead to patulous Eustachian tube dysfunction. To differentiate between these conditions, physicians must perform a thorough history, physical exam, and diagnostic testing, including the ETDQ-7 symptom score, both otoscopy and nasopharyngoscopy, and audiometric testing, including tympanometry.

Aural fullness work up.

Nasopharyngoscopy should be performed with an endoscope directed 45 degrees laterally and superiorly to the nasal floor in the ipsilateral nasal cavity to optimize the view of the Eustachian tube orifice posteriorly to the inferior turbinate, which in turn can be used to evaluate for inflammation and neoplastic disease in the Eustachian tube. The most common findings during endoscopy in dilatory ETD are mucosal inflammation, hypertrophy, high amounts of mucus, and cobble-stoning. Finally, otoscopy may reveal tympanic membrane retraction or effusion, but retraction pockets due to dilatory ETD can still progress because of inflammatory mechanisms regardless of whether the ETD has resolved.

If the patient has been symptomatic for greater than 12 weeks, a positive ETDQ-7 score and impaired ventilation demonstrated by Type B (flat with no clear peak) or C (middle ear pressure > −100 dPa) tympanogram, they are a candidate for BDET, and more testing is usually not necessary unless the patient has an atypical history or unclear pathology. If required, a CT scan can provide further information about anatomical obstructions and the interaction between the internal carotid artery and the Eustachian tube.

However, if the initial workup is normal or inconclusive, but symptoms persist, then a myringotomy can be performed to bypass the Eustachian tube and temporarily improve middle ear ventilation. If symptoms improve immediately postmyringotomy, this is indicative of inadequate ventilation and is consistent with baro-challenge ETD, making the patient a suitable candidate for BDET. These patients usually have strong outcomes following BDET.

For symptomatic patients with type A tympanograms, caution and objective testing should be used before proceeding with BDET. For example, tympanic reflex decay testing can identify tympanic membrane movement with respiration, which would indicate a patulous Eustachian tube.

It is important to distinguish dilatory and patulous ETD. A type A tympanogram with positive reflex decay and worsening autophony/fullness may indicate patulous ETD, while a type B or C tympanogram indicates dilatory ETD. Moreover, tympanic membrane movement and nasal breathing indicate patulous ETD, while dilatory ETD is indicated by a different constellation of symptoms, such as middle ear fluid buildup (effusion) or atelectasis (nonfixed tympanic membrane retraction).

A CT scan of the Internal Auditory Canal and Vestibular Evoked Myopotentials is recommended in all patients with sensitivity or vertigo with loud sounds, as it may confirm a diagnosis of superior canal dehiscence syndrome. In the case of fluctuating hearing loss, electrocochleography can be performed to evaluate cochlear hydrops. In patients with type A tympanograms whose symptoms do not resolve following myringotomy, with normal tympanic reflex decay, cervical and ocular VEMPs may have referred aural fullness secondary to sinusitis, which can be confirmed on a CT scan of the sinuses.

The use of BDET for dilatory ETD was first reported by Ockerman in 2009. Later, Kivekas et al. found evidence that a two-minute balloon dilation causes both shear and crush injury of the epithelium while allowing for rapid healing by sparing the basal layer. In addition, a fibrous scar in the epithelium is caused due to the crushing of lymphoid follicles and lymphocytes. Moreover, Smith et al. recently showed that the balloon creates microfractures in the cartilaginous framework of the Eustachian tube. This combination is believed to improve middle ear ventilation and Eustachian tube dilatory function via a reduction of the inflammatory burden.

Before performing any surgery, medical treatment of Eustachian tube dysfunction should be attempted, including treating underlying inflammatory disorders and a trial of either 4 weeks of nasal steroids or 1 week of oral steroids. While steroids alone have not been shown to significantly improve symptoms of ETD, they are effective when used with the Valsalva maneuver before BDET.

This surgery is typically performed in three steps: (1) insertion of a balloon through the nasopharynx into the Eustachian tube via a catheter; (2) inflation of the balloon for approximately 2 minutes; (3) removal of the system after full dilation of the balloon has occurred.

Overall, this surgery has been demonstrated to be efficacious, with low complication rates and high rates of clinical improvement in ETDQ-7 questionnaires being demonstrated in multiple randomized controlled trials. BDET is currently the only FDA-approved treatment for dilatory ETD.

Before considering BDET under local anesthesia, a nasopharyngoscopy should be performed to evaluate anatomical challenges that may limit surgical access to the nose. Some examples of these challenges may be septal abnormalities, lateral adenoid hypertrophy, extension of the inferior turbinate into the nasal airway, and other conditions that may cause nasal obstructions. If obstructions are found, a physician may choose to use a more controlled environment, such as the operating room, to perform this surgery, in addition to any adjunctive procedures.

Some considerations that must be taken to ensure that adequate anesthesia is administered for BDET. The approach through the nasopharynx requires good topical anesthesia for the nasal cavity, as this will allow for easier instrument insertion into the nasal passages. It is important to disrupt the neuronal reflex arc, which is made up of the mechanical tympanic membrane, the promontory, and the nasopharynx. This arc is uniquely sensitive to barometric changes, as the middle ear pressure may change during this procedure.

To address these concerns and minimize discomfort, anesthesia should be administered with these concerns in mind. Patients should be premedicated with a vestibular suppressant (e.g., 2.5 mg diazepam) 90 minutes before the procedure, followed by another dose of vestibular suppressant and 5 mg hydrocodone. Then, once the patient arrives at the clinic, oxymetazoline should be sprayed into each nostril, and 3–5 drops of 7% lidocaine/7% tetracaine should be compounded into an otic solution and placed on the ipsilateral tympanic membrane via the external auditory canal. Additionally, two cottonoids soaked in 2% tetracaine should be left along both sides of the nasal floor for ten minutes. After removal, 0.5 mL of compounded tetracaine and lidocaine cream should be applied via a cannula to the Eustachian tube orifice. The topical anesthetics of the tympanic membrane will work in conjunction with the lidocaine cream to disrupt the isobarometric reflex. Finally, the tetracaine cottonoids should be once again applied for 5 to 10 more minutes along the nasal floor, after which the physician can continue with surgery ( Fig. 54.2 ).

In-office BDET anesthesia protocol.

In the case of BDET, there are three subsets of FDA-approved balloon catheters available: flexible catheters with a noncompliant balloon, rail-based catheters with noncompliant balloons, and rail-based catheters with semicompliant balloons.

Noncompliant flexible balloon catheters are usually made of polyester or nylon. These devices consist of 6 × 16 mm noncompliant flexible balloon catheters to be introduced by a 55-degree angled guide into the nasopharyngeal orifice of the Eustachian tube. Under endoscopic view, the catheter should be gently advanced upward through the external auditory canal (S-shaped curve of the Eustachian tube) until resistance is met at the isthmus, the narrowest, bony-cartilaginous portion of the canal. Once fully inserted, the yellow mark should be visible along the medial edge of the anterior cushion of the Eustachian tube, to ensure that overinsertion of the balloon has not occurred. While the balloon’s position is maintained by the surgeon, the assistant should then inflate the balloon at 1 ATM every second until the balloon is 12 ATM, where it should be held for 2 minutes. After 2 minutes of 12 ATM, the balloon should be deflated and carefully retracted. Finally, the entire catheter-guide system is removed from the nose.

Rail-based noncompliant balloon catheters consist of a stiff, malleable core made of metal or hard plastic and may also come with sliding rail systems. The procedure for rigid balloon catheters with rail systems usually consists of placing a 45-degree bend at the 2 cm mark on the distal end of the rail or catheter, which will visually indicate the depth of the Eustachian tube cannulation. Under endoscopic view, the rail, or tip of the balloon, will be introduced into the Eustachian tube orifice, and the balloon is then advanced until the rail is even with the medial edge of the anterior cushion of the Eustachian tube. When it cannot be advanced further, it has reached the bend in the rail. Then, while the balloon’s position is maintained by the surgeon, the assistant should inflate the balloon at 1 ATM every second until the balloon is 12 ATM, where it should be held for 2 minutes and deflated. If using an 8 mm balloon, it is recommended to perform two dilations at staggered lengths, due to the length of the cartilaginous Eustachian tube (24 mm). After the dilation is complete, the full dilation system should be removed. The semicompliant balloon systems follow a similar workflow but use an angled guide catheter to insert the balloon within the Eustachian tube Orifice.