Keywords

Background

Acute otitis media (AOM) and secretory otitis media (SOM) or otitis media with effusion (OME) [1] is fairly well defined in international recommendations. The difference basically is that while AOM is an infectious disease with acute onset, SOM is the presence of effusion in the middle ear without any associated signs of acute ear infection. It is thus different from AOM, which causes pain and symptoms of acute illness, in having much less obvious symptoms and not having an acute onset. SOM might cause a substantial hearing loss which if present for longer periods can affect both speech development and behavior [2].

Most children experience a few episodes of AOM, while almost all will suffer SOM for shorter periods during and after upper airway infections [3]. Also, most episodes of AOM are followed by an episode of SOM. In most countries, the recommended treatment for both uncomplicated sporadic AOM and SOM is watchful waiting. This is since they tend to be self-limiting, healing well in most cases without treatment or sequele.

In some instances, however, the child will experience recurrent episodes of AOM. The definition of recurrent AOM (rAOM) is agreed to be when there is three or more episodes in 6 months, or four in 1 year with the most recent in the last 6 months [4]. These children and their families experience a substantial impact on quality of life that actually has been shown to be comparable to childhood asthma [5]. Repeated episodes of AOM are also related to frequent antibiotic use, since most guidelines recommend antibiotic treatment of these children. Children with rAOM will also suffer frequent, perhaps prolonged, periods of SOM.

SOM might also have a more complicated course with repeated or perhaps long-standing periods of hearing loss. It has been suggested that these episodes could affect not only hearing but also speech development, general behavior, and perhaps vestibular function [6, 7]. No long-term effect of antibiotics has been shown in the treatment of SOM [8], and no other medical treatments are recommended [9].

History of Ventilation Tubes

Already in 400 BC, the Hippocratic school described middle ear effusion that could be relieved by incising the eardrum [10]. Myringotomy was practiced to relieve “deafness” with various success during the centuries thereafter. A more scientific approach to myringotomy was begun in the late eighteenth century, and in 1801 Astley Cooper presented two papers to the Royal Society showing that myringotomy indeed could improve hearing. He was aware that bone conduction must be present and to ensure this he placed a watch on the patients’ incisors or mastoid and made sure they could hear it better than when it was held near the outer ear [11]. Later in the nineteenth century, Adam Politzer is credited with the first use of suction to remove fluid [12]. He is also thought to have designed the first ventilation tube, in an attempt to overcome the problem of keeping the perforation open for a longer period. Several other attempts were done to keep the perforation open. They however met with very little success, and the attempts were abandoned. It was not until 1954 that a vinyl tube that was successful in airing the middle ear was introduced by Beverly Armstrong [13], and the use of ventilation tubes was introduced worldwide.

Effect of Ventilation Tubes

Ventilation tubes have now been used in the treatment of middle ear problems for many years. The tubes are not supposed to drain the ear but to overcome the pressure differences and ventilate the ear. In this way, they fulfill the double purpose of preventing collection of fluid in the middle ear and create a better environment for the middle ear mucosa.

Ventilation tubes are used in both rAOM and SOM, and indeed many of the children treated with ventilation tubes will suffer from a combination of both. When used in rAOM, the main indication is reducing the numbers of AOM episodes while in SOM the main indication is to better the hearing [9].

In a Cochrane review [14] published in 2018, it is concluded that children receiving grommets are less likely to have AOM recurrences compared to those managed by active monitoring or placebo medication. However, the effect is modest already during the first six months and even lower after 12 months.

Another Cochrane review [15] states that no effect was seen on speech development in otherwise healthy children after ventilation tube placement.

Some studies have however shown a positive effect on quality of life (QoL) of children with OM after insertion of ventilating tube [16], especially in those suffering from both rAOM and severe SOM. There are also indications in all studies that ventilation tubes should be considered earlier in otherwise impaired children. In several studies, it has been stated that ventilation tubes for rAOM should only be considered if there are persistent SOM in one or both ears [17,18,19,20]. There is also an ongoing discussion on the additive effect of ventilation tubes and adenoidectomy in the treatment of rAOM. There seems indeed to be a modest effect on the number of recurrences, especially in children under the age of two years, if adenoidectomy is done when placing tubes [21, 22].

Since keeping antibiotic use low in children is strongly suggested to reduce the risk of antibiotic resistance in upper airway pathogens, prolonged antibiotic treatment is not recommended as first-line treatment in rAOM. It has also been suggested that ventilation tubes may reduce the severity of AOM recurrences and allow for topical rather than oral antibiotic treatment of AOM episodes which would make the impact on antibiotic use greater than the reduction in numbers of episodes would suggest.

SOM mostly resolves spontaneously; thus, all current guidelines recommend a three-month period of watchful waiting in children with SOM who are not at particular risk for speech, language, or learning problems. Medical treatments such as decongestants, antihistamines, and oral/intranasal corticosteroids are either ineffective or may cause adverse effects [23,24,25]. Ventilation tubes are thus the main option in children with SOM and hearing impairment lasting more than 3 months [26, 27].

The most common problem in children treated with ventilation tubes is ear discharge. It has been shown that in small children, it is often caused by an AOM while in older children it is more often caused by contamination through the ear canal. It has also been shown that topical treatment with ear drops is sufficient in most cases and oral antibiotics seldom are needed [28, 29]. Probably due to biofilm formation, some patients will experience prolonged periods of otorrhea, sometimes resulting in the need for removal of the tube [30].

The other major risk is that of persistent perforation of the tympanic membrane. When using modern tubes, it has been shown to be low. The long-term results after ventilation tube treatment are good, although more tympanosclerosis are seen in patients treated with ventilation tubes [31, 32]. Some have claimed that the use of ventilation tubes might cause more cholesteatomas to develop, while others have claimed that tubes could prevent the formation of cholesteatomas. No conclusive evidence has been found of either theory [33, 34].

Different types of ventilation tubes have been tried both concerning design, material, and coating. Tubes designed to stay longer have a greater risk of causing persistent perforations and tympanosclerosis [35]. On the other hand, early extrusion is a problem in some patients causing re-operations. This risk seems to differ with different kinds of tubes [36].

It is interesting to note that there are great regional differences in the use of ventilation tubes, indicating that indications vary not only over time but also regionally. Denmark is probably the country where most tubes are used with a prevalence as high as almost 30% during the first three years of life [37], while neighboring Sweden have much lower rates. It is also interesting to note that although some countries have shown a declining rate of ventilation tube use after the introduction of vaccine against pneumococci, this has not been the case in Denmark.