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Tympanostomy tubes: Eustachian tube bypass with imperfections
Insertion of tympanostomy tubes is often recommended to improve middle ear ventilation in children with acute otitis media (AOM) and otitis media with effusion (OME). First introduced in 1869 by Dr. Adam Politzer, early hard rubber tympanostomy tubes soon fell into disfavor until vinyl ventilation tubes were introduced in 1954 by B.W. Armstrong. About one of every 110 U.S. children had ventilation tubes inserted in 1996, double the number of tonsillectomies performed. In short, it is now the most common surgical procedure performed in children under general anesthesia.
Bilateral insertion of tympanostomy tubes (myringotomy and tubes) is usually done for three major indications: 1) unilateral or bilateral chronic OME (>three months), especially when accompanied by a conductive hearing loss in excess of 20 dB or by symptoms of persistent middle ear congestion; 2) recurrent AOM (>three separate episodes within three months with at least one recent episode); or 3) two or more breakthrough episodes of AOM during antimicrobial prophylaxis for recurrent AOM.
Tubes are also conservatively recommended for children who have experienced four episodes in a six-month period or six episodes in a 12-month period. Ventilation tubes have achieved longer disease-free intervals and improved hearing in children with OME than myringotomy alone and than medical management alone. Multiple studies have demonstrated a reduced frequency of ear infections in children with a history of recurrent AOM after ventilation tube placement.
Less common indications for the procedure include acute suppurative mastoiditis and Eustachian tube dysfunction with middle ear atelectasis or a persistent tympanic membrane retraction pocket.
The procedure produces large short-term improvements in quality of life for most children. In one survey of changes in quality of life after tympanostomy tube placement, 56% of 224 parents noted a large improvement, 15% moderate improvement and 25% a small or trivial improvement. Much of the parent dissatisfaction with the procedure is due to complications of chronic otorrhea or premature extrusion of the tubes.
The purpose of this article is to present a current overview of tympanostomy tubes. Highlighted will be information about indications, water precautions, use of ototopical antibiotic drops for prevention and treatment of acute otorrhea, and anesthetic and procedure complications. Suggestions will be given for in-office management of an obstructed tympanostomy tube.
Types of tubes and placement
Although most tympanostomy tubes are made of Teflon, stainless steel or similar material, many other materials have been used. There is some evidence that impregnation with silver oxide diminishes postoperative otorrhea and use of ionized, coated fluoroplastic tubes may prevent bacterial colonization and formation of a biofilm. Manufacture with thermoplastic elastomers may reduce early clogging of the lumen of tubes.
Tympanostomy tubes are generally divided into two categories, those that typically function for about nine or 10 months and those that stay in place for several years (Goode T-tube, Paparella tube). The latter group typically includes anchoring to the tympanic membrane by means of wings or toggle bolt design that prevents early extrusion. Depending on the design and anchoring device, long-term tubes have a much higher rate of persistent perforation of the tympanic membrane when the tube is spontaneously extruded or surgically removed.
There are three reasons tympanostomy tubes are optimally inserted in the anterior-inferior part of the tympanic membrane: purported longer interval of tube retention (controversial), location directly opposite the natural opening of the Eustachian tube into the middle ear and avoidance of injury to the round window if the tube were placed in the posterior inferior quadrant.
Complications of tube insertion
Intraoperative complications of performing myringotomy and placing a ventilating tube are few. Dislocation of the incudostapedial joint, severing the facial nerve and puncturing an exposed jugular bulb are serious but rare complications. In children with extremely small external auditory canals, placement and follow-up of ventilation tubes can be a challenge. This is especially an issue in children with stenotic ear canals such as those with Down syndrome. The stenotic external auditory canal may also influence the surgeon to choose a smaller grommet style tube, such as a Tiny-Tef tube. These have the disadvantage of staying in the eardrum for a shorter time. Children with chronic Eustachian tube dysfunction may require repeated insertion of ventilation tubes. This may result in an atretic (thinned out) tympanic membrane. It is not good technique to insert a tympanostomy tube through an atretic section of the tympanic membrane. The tube can be inserted high in the anterior superior quadrant through a stronger part of the tympanic membrane.
One of the major concerns parents have is the safety of the general anesthetic. Hoffmann and colleagues evaluated 4,000 consecutive children who had tubes placed for possible complications of the general anesthesia and found no serious complications. Fewer than 1% had airway obstruction that required intervention with muscle relaxants or insertion of an endotracheal tube. They concluded that myringotomy with ventilation tube placement is an extremely safe procedure.
The most common immediate postoperative complication of tympanostomy tube insertion is otorrhea through the lumen of the tube. Following tube insertion, otorrhea occurs in approximately 10% of cases, most commonly when a mucoid or purulent effusion is aspirated at the time of myringotomy. Post-tube insertion otorrhea typically will clear with ototopical therapy. Most children with tympanostomy tubes will have at least one episode of otorrhea per year that the tubes stay in place. Otorrhea that occurs after the postoperative period usually results from: 1) nasopharyngeal secretion reflux into the middle ear; 2) tube-associated granulation tissue; or 3) contamination within the external canal from swimming in lakes or pools. Ototopical antibiotics alone have shown great efficacy in resolving otorrhea from most causes.
Ofloxacin (Floxin Otic, Daiichi) and ciprofloxacin-hydrocortisone (Cipro HC, Alcon), topical antibiotic preparations with no known ototoxicity, are the newest generations of ototopical agents available for use in patients with draining ears and tympanic membrane perforations. Some investigators suggest that tubes impregnated with silver oxide may reduce the incidence of postoperative otorrhea. Alternatively, tubes manufactured with an ion-balanced method reportedly have theoretical advantage from less biofilm accumulation on the inner surface of the tubal lumen, with presumed decrease in the incidence of postoperative otorrhea.
Malis recently reviewed management of pediatric tympanostomy tube otorrhea and came to several conclusions. His review found that ear canal antisepsis prior to tympanostomy tube placement does not reduce the incidence of early post tympanostomy tube otorrhea. The presence of active AOM at the time of surgery does increase the risk of early otorrhea.
Otorrhea may demonstrate seasonal variation, being associated with upper respiratory infections in the colder months and with immersion under water in the warmer months. Water precautions for surface swimming in children with tympanostomy tubes are now considered unnecessary in most children. Otorrhea rates in swimmers with tubes are comparable with or without dry ear precautions. However, diving, head dunking, exposure to soapy water and specific water types, such as lake or river water, are independent variables that may warrant precautions. Rarely, tympanostomy tubes themselves incite a chronic inflammatory reaction that fails to respond to routine office management and requires removal of the ventilation tube.
| Sequelae related to tympanostomy tube insertion include scarring of the tympanic membrane and tympanic membrane atrophy. |
The average grommet style tube stays in the tympanic membrane for about 10 months (range six months-24 months) and rarely requires surgical removal. Ventilation tube duration and extrusion rates do not appear to be related to quadrant of placement. Most children exhibit normal tube extrusion parameters requiring, perhaps, office management for crusting and debris build-up. After some months, granulation tissue can develop around the orifice of the tube or within its lumen. It may present with a weeping ear or with spots of blood on the child’s pillow. A course of antibiotic-corticosteroid ototopical drops may shrink the granulation tissue, allowing for reventilation of the middle ear. On occasion, a retained tube will require removal under general anesthesia
Sequelae related to tympanostomy tube insertion include scarring of the tympanic membrane (tympanosclerosis) and tympanic membrane atrophy. Tympanosclerosis may occur in 26% to 50% of tympanic membranes with ventilation tubes but the tympanosclerosis is rarely identified within the middle ear and the hearing is not usually affected. Atrophy and atelectasis result from the loss of the middle fibrous layer of the healed tympanic membrane after tube extrusion. Continued Eustachian tube dysfunction after tube extrusion may cause retraction of an atrophic area of the tympanic membrane with a predilection for the region of the pars flaccida. This may increase the risk of cholesteatoma formation within a retraction pocket. A persistent perforation may be noted following extrusion of the tube. Rates of perforation vary depending upon the type of tube, with grommet style tubes having a perforation rate of up to 4% and unmodified Goode T-tubes having a perforation rate as high as 12% to 25%. Rare complications include the development of an implantation cholesteatoma at the site of the tube insertion.
Practice guidelines
In a survey study initiated by the Pediatric Otolaryngology Committee of the American Academy of Otolaryngology-Head and Neck Surgery, 1,200 general and pediatric otolaryngologists responsible for the placement of 75,000 myringotomy and tube insertions in children per year were asked to comment on their current practice for tympanostomy tube follow-up. Based upon the results, practice guidelines for primary care physicians were generated that include an otolaryngology follow-up within the first month and then at regular intervals (every three to six months) until the tubes are out and the Eustachian tube function has normalized. The Committee concluded that earlier referral back to the otolaryngologist should be made when 1) a tube is occluded or cannot be visualized; 2) when otorrhea or granulation tissue fails to resolve after an appropriate course of therapy; 3) when hearing loss or speech or language delays occur in children with ventilation tubes; and 4) when there is evidence of structural ear disease, such as atelectasis, retraction pockets or squamous debris. The AAP has recently adopted these recommendations into published guidelines for their members.
Tympanostomy tubes are neither a panacea nor an example of unnecessary surgery. Application of judicious criteria for insertion of tympanostomy tubes is highly recommended and accepted by most otolaryngologists and pediatricians.