Perforation

9.2.1 Prevalence and Classification

Perforation of the eardrum is a common childhood event (see ▶ 7). Box 9.1 shows the causes of TM perforations in children. The most common is perforation with an acute otitis media (AOM), which will usually heal quickly and spontaneously. Repeated infections can lead to a nonhealing perforation—one form of chronic suppurative otitis media (CSOM). In the developed world, the next most common cause of central persistent TM perforation is following extrusion of short-term ventilation tubes (grommets) and occurs in approximately 2.2% of ears or 4.4% of patients treated with grommets, and in 16.6% of those treated with long-term tympanostomy tubes (see ▶ 8). ¹

Factors that predispose to perforation are poverty, deprivation and low socioeconomic status, recurrent otitis media, Eustachian tube (ET) dysfunction, atrophic segments with poor drum vascularity, and the presence of retractions. Ethnicity also plays a role; the highest prevalence of recurrent otitis media is in Australian Aborigines, Native Americans, Indians, and Inuits. ² Low rates are found in South Koreans. This ethnic variation is independent of socioeconomic factors.

CSOM has traditionally been classified as:

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  Tubotympanic, where there is a central perforation (i.e., of the pars tensa), usually without cholesteatoma, that is, “mucosal” disease.

  
  
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  Atticoantral, in which there may be a marginal retraction, marginal perforation, or attic (pars flaccida) disease with a greater likelihood of cholesteatoma.

The central perforation, tubotympanic, type is traditionally considered “safe”, whereas atticoantral disease with cholesteatoma is considered “unsafe.” If by safe we mean “unlikely to cause deeper erosion of the ossicular chain or temporal bone over the otic capsule,” then this terminology is correct, but if by unsafe we mean a greater likelihood of complicated ear disease leading to meningitis or brain abscess, then the distinction is less clear. Browning ³ showed that both forms of CSOM can lead to brain abscess, although the risk is less after a modified radical mastoidectomy or in mucosal disease and greater in the presence of cholesteatoma.

The risk of intracranial infection in the presence of an untreated active CSOM with or without cholesteatoma has been estimated in a 30-year-old adult to be 1 in 10,000 per annum or a lifetime cumulative risk of 1 in 200. ⁴ The risk for young children is probably higher as intracranial sepsis occurs mainly in children under the age of 3 years.

9.2.2 Pathophysiology and Flora

In association with a persistent perforation, mucosal changes in the middle ear include hyperplasia, metaplasia, increase in goblet cells, tympanosclerosis, bone destruction, and arrest of pneumatization of the mastoid air cells.

A perforation is often quiescent with no active infection but the most common pathogenic organisms cultured in a long-standing perforated ear are Staphylococcus species followed by Proteus species and then by Pseudomonas infections. Escherichia coli and Klebsiella species are also common. In contrast, otorrhea through a grommet is more likely to be caused by Streptococcus pneumoniae, Pseudomonas, Haemophilus, or Moxarella species.

9.2.3 Clinical Features of Tympanic Membrane Perforation

The severity of the hearing loss is highly variable. The child with a small central perforation or anterior perforation may have normal hearing, whereas a large or subtotal perforation may cause a 50-dB conductive loss. In general, the larger the perforation, the larger the air-bone gap. The low frequencies are most affected. In one study, ⁵ the site of the perforation, anterior or posterior, was not a significant factor. Experience, however, suggests a definite trend toward greater conductive loss from posterior perforations. This is usually attributed to loss of the “baffle” effect when the round window membrane becomes exposed to direct in-phase sound waves. However, in the aforementioned study, ⁵ the severity of the conductive hearing loss depended upon the sound pressure differential across the TM, which is inversely proportional to the middle ear and the mastoid air volume. This can be measured from the tympanogram if a good seal is obtained. The smaller the middle ear volume, the greater the air-bone gap seen on the audiogram. ▶ Fig. 9.1 shows a large dry central perforation.

9.2.4 Management of Tympanic Membrane Perforations

Nonsurgical Management

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  Otorrhea is managed as needed if the discharge warrants it, with microsuction in a cooperative child, or by mopping the ear and prescribing topical nonototoxic eardrops with or without steroids.

  
  
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  Use of aminoglycoside-containing ear drops three times daily is generally considered safe in an infected ear for 1 to 2 weeks, but should not be continued for fear of ototoxicity. Topical quinolone drops such as ciprofloxacin or ofloxacin (which in the United Kingdom are available as an eye drop formulation), either given alone or with a topical steroid drops such as betnesol is an effective alternative choice and carries no risks of ototoxicity.

  
  
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  Persistent or repeated discharge despite treatment requires an ear swab for microbiology culture and sensitivity.

  
  
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  If topical antimicrobials alone are insufficient, oral broad-spectrum antibiotics can be added. Co-amoxiclav will usually be effective unless the infection is caused by Pseudomonas, in which case oral ciprofloxacin for a week is advised and is generally safe.

  
  
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  If the child has anything other than a very small perforation, parents should be advised to protect the ear with earplugs when the child is swimming. The author recommends the use of ear protection in the form of over-the-counter earplugs or custom-fitted water protective plugs from an audiologist for swimming in all children under the age of 2 years with a perforation, and in older children if the perforation is estimated to be 3 mm across or larger. Diving should be avoided without fitted plugs. In the bathroom, the head should not be immersed under the water or directly showered. Cotton wool with petroleum jelly (e.g., Vaseline, Unilever) as an earplug may be used in the younger children in the bathroom.

  
  
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  In a child with bilateral perforations and a significant hearing impairment who is not yet suitable for surgical repair, amplification must be offered. If infections are infrequent, conventional acoustic air-conduction hearing aids may be effective with an open or vented mould. Where infections are more frequent or become so, after a trial of an air-conduction hearing aid, a bone-conduction hearing aid, Softband (Cochlear Ltd.) (see ▶ 15) or very occasionally bone-anchored hearing aid (BAHA) can be considered.

  
  
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  A child with unilateral perforation and significant hearing loss but a normal or nearly normal-hearing contralateral ear most commonly prefers to avoid the use of a hearing aid and manages well. The school should be informed about the side of the unilateral loss (see ▶ 14).

Surgery

Terminology

Surgical repair of a persistent TM perforation (myringoplasty) either on its own or in combination with middle ear surgery (tympanoplasty) at the appropriate age is usually a highly successful operation. The common indications for myringoplasty or tympanoplasty are shown in Box 9.2.

In 1956, Wullstein described his classification of tympanoplasties ⁶:

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  Type I (myringoplasty) involves a repair of the TM only; the three ossicles are intact.

  
  
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  Type II tympanoplasty is a reconstruction preserving the middle ear depth, but where there has been erosion of the malleus or incus, some form of ossiculoplasty is undertaken.

  
  
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  Type III tympanoplasty involves a graft laid onto the stapes suprastructure with a shallower middle ear cleft.

  
  
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  In type IV tympanoplasty, all three ossicles are lost, and the graft is on the footplate and covers the round window niche.

  
  
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  Type V operation is for a fixed footplate, now being of historic interest; this was the “‘fenestration” of the lateral semicircular canal used for otosclerosis before the popularization of stapedotomy and stapes prostheses.

Timing of Surgery

The medical literature does not give a clear answer as to the ideal age for reconstructive middle ear surgery. Randomized controlled trials have not been undertaken and expert opinion is derived from large case series and personal experience. Smyth and Hassard ⁷ reported successful surgery at a young age (5 years). Strong suggested that tubal cartilage and tensor palati muscles grow sufficiently after 7 years and so recommended surgery after this age. ⁸ However, Nagai et al felt that myringoplasty is warranted for younger children aged 7 to 12 years only if they have large mastoid pneumatization, ⁹ otherwise it is best to wait until children are 13 years and older. Most of the pediatric published series report a mean age of 10 or 11 years for myringoplasty.

When an eardrum is repaired in a very young child, the risks of sequelae of hearing loss from recurrent persistent otitis media with effusion (OME) behind the repair and of continued AOM perhaps with reperforation become higher.

When the patient has a unilateral perforation, the decision is fairly straightforward. Repair is indicated if the child wishes to undertake frequent swimming, has a significant unilateral hearing loss, or is still getting infections, assuming that the contralateral ear is healthy with a normal or near-normal tympanogram and good ET function. A perforation that has resulted from a ventilation tube will typically show this clinical picture and can be repaired from the age of approximately 7 years. Factors such as a previously repaired cleft palate, a child with Down’s syndrome, or a craniofacial anomaly need to be considered as they will adversely influence ET function, thus reducing the success rate.

The author will occasionally recommend tympanoplasty surgery at a much younger age, at the youngest 18 months, more typically at 3 or 4 years. The reason for operating early in these cases is substantial bilateral hearing loss from subtotal perforations, or unmanageably frequent and troublesome otorrhea. In the latter situation and with an intact eardrum albeit with the likely middle ear effusion, a dry ear will be much more acceptable to the family than chronic or very frequent discharge. Beware the child with a persistent purulent unilateral discharge. Not infrequently this will be caused by an attic cholesteatoma, which can be difficult to identify in a small and fractious child, and the management is very different, as covered in ▶ 10.

The medical literature has been equally contradictory with regard to whether the success rate is influenced by the presence of a discharging ear. The author’s view concurs with that of Lau and Tos ¹¹ that tympanoplasty results are poorer when the ear is actively infected at the time of surgery. A slightly moist but not purulent ear, however, can be operated upon without concern. Sometimes it proves almost impossible to achieve a dry ear preoperatively. Ear swabs, topical agents, and oral antibiotics are all helpful for a planned operation, which can then go ahead despite the discharging ear and with the use of postoperative antibiotics as well.

Adenoidectomy before or with Tympanoplasty

There is a nonsignificant trend in some published series suggesting that tympanoplasty surgery may have better outcomes if adenoidectomy has been undertaken. ¹² The TARGET (Trial of Alternative Regimes in Glue Ear Treatment) trial data ¹³ clearly indicates that ET function is improved in the younger child by adenoidectomy. Therefore, if the clinical suspicion is of persistent adenoids or if tympanoplasty surgery is being undertaken at a young age, concurrent adenoidectomy may be advantageous.

Surgical Outcomes of Tympanoplasty

Most published series of pediatric myringoplasty show a high success rate in terms of closure of the perforation and graft take with figures from 71% to well over 90%. ¹⁴ Over a longer follow-up period, however, the success rates can fall off to approximately 65%. Hearing gain in the author’s experience is usually exceptionally good in pediatric myringoplasty unless there is an ossicular problem or poor middle ear aeration, and normal or near-normal hearing can be expected. Published series, however show closure of the air-bone gap to within 10 dB in only two-thirds of cases. ¹⁰

The risk of the OME persisting after the drum is repaired in the pediatric population will depend upon the patient’s age, but one report gives a figure of 7.8%. ¹⁰ While early drum repair is usually highly successful, there is also a longer-term graft breakdown rate with reperforation, which has been estimated at 12.5% after 2 years. ¹⁵

Smaller permeatal procedures such as “Gelfoam” and fat plug myringoplasty will carry lower success rates but may be suitable for small perforations, and have the advantages of taking little time and avoiding morbidity such as surgical scars.

Surgical Technique

The surgical approach for a tympanoplasty can be permeatal, endaural, or postaural. There is increasing interest in and experience with endoscopic techniques. ¹⁶

Because of the relatively small meatus in childhood and for better access to the anterior mesotympanum, the author recommends a postaural approach. The graft material can be temporalis fascia or perichondrium, but periosteum taken from the immediate postaural mastoid bone also provides an ideal material. (The place for cartilage tympanoplasty is discussed later in relation to retractions.)

The edges of the perforation should be freshened, and an underlay technique with resorbable sponge support in the middle ear is fairly standard. If there is a small-to-moderate posterior perforation, then a “reverse through-lay” repair is very successful ( ▶ Fig. 9.2).

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  In this technique, as the meatal flap is elevated to the annulus, a Plester D-knife is used to continue lifting the epithelial layer off the fibrous surface of the TM, without dislodging the annulus or entering the middle ear.

  
  
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  This flap is continued toward the front of the perforation.

  
  
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  Resorbable sponge is placed through the perforation only under the anterior margin, and the graft is then placed as an onlay on the fibrous layer of the drum posteriorly but under the lip of the perforation anteriorly with the sponge supporting it.

  
  
  
  

  

  
  

  Fig. 9.2 Reverse through-lay myringoplasty: the graft sits on the fibrous layer posteriorly and under it anterior to perforation.

For a larger or anterior perforations and where the ossicular chain requires repair, an underlay technique is required.

Anterior perforations are technically more difficult to repair. There are two danger areas:

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  First, a lot of sponge support is required anterosuperiorly in front of the lateral process of the malleus so that the graft can be tucked tightly under the drum remnant.

  
  
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  The second area requiring attention is the anterior annulus where after freshening the perforation margin, there is only a tiny lip under which the graft can be placed. The option here is either to use a lot of sponge support and feed the anterior edge of the graft into a submucosal pocket down the ET or, as is the author’s preference, to create an anterior canal wall tunnel and draw a small tongue of graft tissue up through this tunnel, thereby ensuring that the graft is secure and cannot fall away.

Finally, antibiotic or antiseptic ear packs are applied to the canal, and it may be helpful to carefully place a small dressing or silastic disc over the grafted drum before using multiple or longer dressings for the ear canal. If the child pulls out the accessible dressing, then the deeper ones will remain in situ. The author’s preference is to use 1-cm-wide ribbon gauze soaked in bismuth iodoform paraffin paste (BIPP) for the ear dressings. Some surgeons do not employ any fiber-based dressings or packs (that need to be removed), instead preferring to fill the ear canal after surgery with antibiotic/antiseptic cream or ointment or even to insert absorbable gelatin sponges soaked in antimicrobial ointment. The wound is closed with resorbable subcuticular sutures so that they do not have to be removed at the first postoperative clinic visit.

9.3 Tubercular Otitis Media

This is now rare in western communities but still presents particularly in the developing world. Infection may occur through the blood-borne route or through the ET. Multiple perforations are described, and pale granulations in middle ear with visible sequestrated bone are typical. Facial palsy may result. Secondary infection and mastoid involvement with pyogenic organisms occurs. Diagnosis is through microbiology and culture and/or typical features on biopsy. Treatment is by limited surgery as dictated by the findings (e.g., removal of granulations and suction clearance) but primarily with antituberculous antimicrobial therapy under the supervision of a pediatric infectious diseases specialist.

9.4 Retraction Pockets

9.4.1 Classification and Natural History

It is helpful to grade the severity of both attic (pars flaccida) and pars tensa retractions in order to document progression or improvement and to allow comparison of treatment regimes in the medical literature. The most commonly accepted classifications are those of Tos and Poulsen for attic retractions (Box 9.3; ▶ Fig. 9.3) ¹⁷ and the Sadé classification (1979) for pars tensa retractions (Box 9.4; ▶ Fig. 9.4, ▶ Fig. 9.5). ¹⁸

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