Tympanostomy Tube

Anatomy and Physiology

A basic understanding of the external ear and an intimate knowledge of the tympanic membrane and surrounding structures are needed to perform tympanostomy tube insertion safely.

The external ear is comprised of the auricle or pinna, which is a funnel-shaped cartilaginous structure that is continuous with the acoustic meatus and external auditory canal (EAC). The EAC is approximately 2.5 cm in length in adults and has both a lateral cartilaginous and medial bony portion. The tympanic membrane (TM) is located at the medial aspect of the EAC, which also makes up a large portion of the lateral wall of the middle ear space. The TM is a three-layered, concave membrane with a middle fibrous layer (made up of an outer radial layer and a deeper circular layer), giving support to EAC skin laterally and middle ear mucosa medially. The fibrous layers integrate laterally to form the annulus. Attached to the medial aspect of the TM is the manubrium of the malleus, with the tip of the malleus forming a small depression in the TM called the umbo.   The TM has a thinner area superiorly known as the pars flaccida (roughly the upper-posterior quadrant of the TM) and a thicker inferior area known as the pars tensa (the remainder of the TM). The TM is approximately 8.5 to 10 mm vertically and 8 to 9 mm in its horizontal axis in adults, with a mean total surface area of ~85 mm, with only approximately 55 mm of the TM being mobile.[4] The blood supply to the lateral surface of the TM is from the deep auricular branch of the maxillary artery and the medial surface by both the auricular branch of the occipital artery and the anterior tympanic artery branch of the maxillary artery. The auriculotemporal branch of the mandibular nerve (V3), the auricular branch of the facial nerve (CN VII), the auricular branch of the vagus nerve (CN X), and the glossopharyngeal nerve (CN IX) supply sensory innervation to the lateral surface of the TM. The glossopharyngeal nerve (CN IX) supplies sensory innervation to the medial aspect of the TM.[5]  Medial to the TM is the middle ear space, which houses the bony ossicles: the malleus, incus, and stapes. The tympanic segment of the facial nerve runs within the middle ear space from anterior to posterior above the oval window and stapes. It then turns 90 degrees, runs inferiorly at the second genu, and runs through the mastoid portion of the temporal bone before exiting the temporal bone through the stylomastoid foramen. A branch of the facial nerve known as the chorda tympani runs from posterior to anterior behind the TM between the malleus and incus, exiting through the petrotympanic fissure. It joins the lingual nerve and gives a taste sensation to the anterior two-thirds of the tongue.

Indications

In 2013 the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) published guidelines on TT insertion in children:

1. "Bilateral chronic otitis media with effusion (OME) for three months or longer AND documented hearing loss.
2. Unilateral or bilateral OME for three months or longer AND reduced quality of life, ear discomfort, poor school performance, behavioral problems, vestibular problems, or other symptoms that could be attributable to OME.
3. Recurrent acute otitis media (RAOM), defined as three episodes of AOM in 6 months or four episodes in 12 months treated with antibiotics, WITH unilateral or bilateral middle ear effusion at the time of assessment for tube candidacy.
4. At-risk children with unilateral or bilateral OME, which is unlikely to resolve quickly for three months or longer. At-risk children are defined as those with permanent hearing loss independent of OME, speech and language delay, developmental disorders including autism, syndromes or craniofacial disorders which include cognitive, speech, or language delays, blindness or an uncorrectable visual impairment, cleft palate, or developmental delay."[6]

In children undergoing repeat TT placement, or children age four years and older receiving their 1 set of TT, adenoidectomy should be considered at the time of TT placement to decrease the risk of repeat surgery.[6][7] Indications for adult tympanostomy tube placement are less well-defined but include chronic Eustachian tube dysfunction (ETD) leading to chronic OME, an atrophic, retracted, and flaccid drum, or a systemic infection of unknown etiology with fluid within the mastoid or middle ear space.[8] Occasionally, TT is needed during hyperbaric oxygen therapy to treat or prevent otitic barotrauma.[9]

Contraindications

There are no absolute contraindications to TT placement. In patients with chronic OME or RAOM not meeting indications as above, watchful waiting or treatment with antibiotics as medically indicated should be performed. Placement of TT outside of the above indications may be performed based on the surgeon’s judgment and after a thorough discussion of the risks and benefits with the parent or patient. Several anatomic variations can be considered relative contraindications to TT placement; these include dehiscence of the facial nerve within the middle ear space, as well as dehiscence or aberrant course of the internal carotid artery within the middle ear cleft.[10]

Equipment

Equipment for tympanostomy tube placement includes an operating microscope or zero-degree endoscope, ear speculums, cup forceps, cerumen loops, 3, 5, and 7F Fraiser suctions; myringotomy knife, alligator forceps, curved pick-ups, and tympanostomy tube(s). Tympanostomy tubes are made of plastic, metal, hydroxyapatite, or silicone. Tympanostomy tubes are typically classified as short-term (lasting 6 to 12 months) and long-term (lasting greater than one year). Beyond this, selecting a particular TT type/shape is a matter of surgeon preference, as numerous short- and long-term TT types exist and have established results.[11]

Personnel

Personnel required for tympanostomy tube placement in the operating room (OR) include a surgeon, an anesthesiologist, a surgical technician, and a circulating nurse.

In the clinic, TT placement can be accomplished with a surgeon and a medical assistant, or a nurse.

Preparation

If tympanostomy tube placement is the sole procedure in children, then general anesthesia with mask ventilation alone is performed. General endotracheal anesthesia is performed in children undergoing additional procedures, such as adenoidectomy or cleft palate repair.

The majority of adolescent and adult patients can tolerate TT placement in the clinic under local anesthesia with topical lidocaine, phenol, or lidocaine injection.

Technique or Treatment

Using an operating microscope with an appropriately sized ear speculum or 0-degree endoscope, the ear canal and tympanic membrane are visualized. Cerumen and squamous epithelium are removed to facilitate visualization and access to the TM. A myringotomy knife is then used to make a radial incision in the anterior inferior portion of the TM approximately 2 mm in length. If a middle ear effusion is present, it can be aspirated using a 5F or 3F Fraiser tip suction.

Saline can be irrigated into the middle ear space to facilitate the removal of thick mucoid effusions. Using alligator forceps, the tympanostomy tube is placed through the myringotomy. This is positioned using a pick or right angle so that the middle ear mucosa is visualized through the tube. Any bleeding usually stops spontaneously but can also be controlled using oxymetazoline or 1 to 1000 epinephrine applied topically to the area. Antibiotic drops are applied and continued several times a day for a few days after surgery to keep the tube(s) patent and reduce postoperative otorrhea risk.

Complications

Tympanostomy tube otorrhea: The most common complication of TT placement and is seen in nearly 1 in 6 (16%) of children within four weeks of surgery and 26% of children during the entire period, the tube is in place.[12] Immediate treatment after TT placement with antibiotic ear drops alone, typically ciprofloxacin or ofloxacin, has been shown to prevent tympanostomy tube otorrhea (TTO), similar to combination antibiotic-steroid ear drops.[13] Water precautions have not been shown to prevent TTO.[6][14]

Tympanostomy tube obstruction: Occurs in about 6-12% of patients. Treatment of obstructed tympanostomy tubes is mainly empiric by manual removal of the blockage or treatment of ear drops such as 5% sodium bicarbonate, 3% hydrogen peroxide, 0.33% acetic acid, or 0.9% sodium chloride drops, with hydrogen peroxide being the least efficacious.[15]

Granulation tissue: This occurs in about 4% of patients. Treat with antibiotic-steroid drops. However, if persistent, consideration for tube removal should be made to eliminate foreign body reactions.[12]

Premature tube extrusion: This can occur within a few months of tube placement. Patients should be reassessed for candidacy for the replacement of tubes.[12]

TM perforation after TT extrusion: occur in 1% to 6% of patients but has been reported to be as high as 10% after TT, which may require myringoplasty or a formal tympanoplasty for repair.[16]

Displacement into the middle ear: This is a rare occurrence in approximately 0.5% of patients. This can be observed or removed if an inflammatory reaction occurs. The development of a perilymphatic fistula has been reported.[17] 

Retained TT: Defined as persistence beyond 2 to 2.5 years. Concerns regarding retained tympanostomy tubes include otorrhea, chronic perforation, granulation tissue, or the formation of cholesteatomas. Options include observation with the treatment of granulation tissue or otorrhea with topical drops as long as they are not persistent versus removing the tympanostomy tube with possible myringoplasty to prevent persistent TM perforation.[18]

Myringosclerosis, tymapnosclerosis, and other tympanic membrane changes are common after TT placement and do not require intervention.[12]

Clinical Significance

Tympanostomy tube placement is the most frequent ambulatory surgery performed in children in the United States. Primary care physicians must know when to refer patients for consideration of tympanostomy tube placement. Otolaryngologists should have intimate knowledge of the indications, contraindications, and risks associated with this procedure to educate their patient’s caregiver properly. The surgeon should have a keen understanding of the anatomy to promptly avoid complications and understand how to promptly manage any post-operative complications. Tympanostomy tube insertion has been shown to improve the quality of life in children.[16] In patients with chronic OME, the prevalence of middle ear effusion is reduced by 33%, and average hearing is improved by 5 to 12 decibels.[6] Tympanostomy tube placement allows for the application of topical drops directly to the middle ear with higher concentrations and limits the use of systemic antibiotics in children.[3]

Enhancing Healthcare Team Outcomes

With tympanostomy tube placement being the most frequent ambulatory surgery performed in children, an interprofessional team approach is imperative to obtaining optimum outcomes for patients, including clinicians (MDs, DOs, NPs, and PAs), specialists (otolaryngologists), nurses, and other health care professionals. General practice clinicians, including family medicine, pediatricians, and internal medicine physicians, play a crucial role in identifying and referring both children and adults who meet the criteria for tympanostomy tube placement to a specialist who can perform the procedure. Nurses can coordinate activities between the different clinicians, assist with the procedure, and counsel patients/parents. The various clinicians must maintain open communication channels and keep accurate, updated patient records.

Likewise, audiologists are crucial in performing both audiograms and tympanograms to identify those children who meet indications for tympanostomy tube placement or require close surveillance prior to referral to a specialist. Because most patients are seen by general practitioners, the American Academy of Otolaryngology has published clinical practice guidelines regarding diagnosing and managing tympanostomy tubes in children.[6] After tympanostomy tube placement, patients require close observation by all team members to assess for complications, tube extrusion, and, if needed, repeated tympanostomy tube placement.