Adhesive Otitis Media and Retraction Pockets

Definition and epidemiology

A retraction pocket forms when part of the eardrum is drawn inwards into the middle ear. Retractions of the taut lower part of the drum (pars tensa) and of the slack part above the short process of the malleus (pars flaccida) are graded separately. The Sadé and Berco (1976) system, the most widely used for the pars tensa, describes four grades; at the most advanced stage the drum adheres to the promontory, which is termed adhesive otitis media. Pars flaccida (attic) retractions are graded with the Tos and Poulsen (1980) system, based on the relation of the pocket to the neck of the malleus and on erosion of the outer attic wall (scutum). Other systems exist, including those of Charachon, Dornhoffer and Erasmus, and inter-observer agreement between them varies (Bayoumy et al., 2022).

A systematic review noted that in civilian populations pars tensa retractions have been reported in 0.3-3.7% and pars flaccida retractions in 14-26% of people (Bayoumy et al., 2022). Among 2200 patients followed for chronic otitis media, 540 (24.5%) had a moderate or severe retraction in at least one ear; in 661 ears the attic was involved in 85.1%, the posterior quadrants in 74.2% and the anterior quadrants in 17.7%, and 64% of ears had more than one area affected (Canali et al., 2023).

Symptoms and signs

Retraction pockets often cause no symptoms and are found on routine examination or hearing screening. When symptoms occur they include mild hearing loss, fullness or blockage and sometimes tinnitus. If keratin collects in the pocket and becomes infected, offensive discharge (otorrhoea) begins, which suggests that cholesteatoma may have developed. In children the picture often comes with long-standing otitis media with effusion or a history of grommets.

On otoscopy a thin, translucent segment of the pars tensa is seen resting on the long process of the incus, the stapes or the promontory; when the long process of the incus has eroded, the drum may sit directly on the stapes head. In pars flaccida retraction the drum is drawn onto the neck of the malleus, and at advanced stages erosion of the scutum is seen. The examination records whether the whole pocket is visible, whether it contains keratin, and whether the drum moves with Valsalva or pneumatic otoscopy. In children with cleft palate, 51% of 37 pars tensa retractions touched the incus and/or promontory at the outset (Parkes et al., 2018).

Causes and risk factors

The underlying cause of retraction is poor ventilation of the middle ear. With persistent Eustachian tube dysfunction, the middle ear gas is absorbed by the mucosa, pressure falls and the weakest parts of the drum are drawn inwards. Inflammation is also central: long-standing effusion and recurrent infection damage the middle fibrous layer, thinning the drum and reducing its elasticity. The pars flaccida lacks an organised fibrous layer and is therefore more prone to retraction (Urík et al., 2021). Tos and Poulsen (1980) described attic retractions particularly after secretory otitis media.

Risk factors include long-standing otitis media with effusion in childhood, recurrent acute otitis media, previous grommets, cleft palate and craniofacial anomalies (Urík et al., 2021; Parkes et al., 2018). Shed skin that falls into the pocket cannot be cleared and accumulates; this mechanism underlies the retraction theory of acquired cholesteatoma. The EAONO/JOS consensus accordingly defines ‘retraction pocket cholesteatoma’ as a separate group of pars flaccida, pars tensa or combined type (Yung et al., 2017).

Audiological and clinical assessment

The diagnosis is made by otomicroscopy or oto-endoscopy, assessing the margins and depth of the pocket, its relation to the ossicles and its contents. Photographs or video allow changes to be compared objectively over time (Parkes et al., 2018). Audiological assessment documents hearing, tracks middle ear pressure and picks up changes that may point to ossicular erosion.

• Pure-tone audiometry: hearing is usually normal or shows a mild conductive loss. In 661 ears with moderate or severe retraction, the air-bone gap was 20 dB or less in 72%. The median gap was 6.25 dB with isolated pars flaccida retraction and 15 dB with isolated pars tensa retraction; in the pars tensa it rose with severity from 7.5 dB to 17.5 and 31.25 dB, whereas in the pars flaccida it showed no significant relation to severity (Canali et al., 2023).
• Deceptively good hearing: when the long process of the incus has eroded, the drum adhering to the stapes head can maintain some sound transmission, so a good audiogram does not prove that the ossicular chain is intact.
• Tympanometry: while the drum is still mobile the trace has a negative peak pressure (type C); when the drum adheres to the promontory or fluid is present, a flat (type B) trace with normal volume is obtained. The normal volume distinguishes it from the large volume seen with a perforation.
• Acoustic reflexes: may be absent in the affected ear when middle ear pressure is markedly negative or there is a conductive loss.
• Imaging: if the base of the pocket cannot be seen, or there is keratin, discharge or bone erosion, high-resolution CT of the temporal bone is requested, with diffusion-weighted MRI when cholesteatoma is suspected.

The key question in the differential diagnosis is whether the pocket has turned into cholesteatoma: a pocket whose base cannot be seen, keratin within it, offensive discharge, a polyp or bone erosion (Tos grade III-IV) all suggest cholesteatoma. A deep, translucent retraction can also be mistaken for a hole on otoscopy; the tympanometric volume helps to separate the two (tympanic membrane perforation).

Treatment and audiological rehabilitation

Treatment aims to prevent progression and cholesteatoma and to preserve hearing. The evidence is weak: a Cochrane review based on two randomised trials with 71 participants concluded that there was no evidence to support or refute a role for surgery (Nankivell and Pothier, 2010). A conservative approach is usually suggested at first for early stages, and there is no clear indication of when surgery should be offered (Spinos et al., 2022). The ENT surgeon decides by weighing age, hearing, and the severity and site of the pocket.

In a systematic review of 27 studies, 76-96% of pockets managed by watchful waiting stayed stable or improved, with complete resolution in 0-38%; perforation developed in 4-6% and cholesteatoma in 1-5%, the latter in pockets in contact with the promontory. About 30% of mild Sadé grade I pockets resolved spontaneously, and about 4% of all pockets were reported to progress to cholesteatoma (Bayoumy et al., 2022). In children with cleft palate, 76% of 37 pockets were stable or better, and cholesteatoma developed in two of the nine that progressed (Parkes et al., 2018).

Surgical options aim either to restore ventilation or to repair the pocket (Spinos et al., 2022). A grommet may be inserted alone or with excision of the pocket; after excision and grommet insertion in 329 patients, persistent perforation was reported in 3-13% and recurrence in 11-25%. Cartilage tympanoplasty was the most frequently assessed approach, in 17 studies of 1030 patients, and lateral attic reconstruction is used for pars flaccida pockets. A consensus-based guide agreed, with 84.6% agreement, that surgery is not superior to watchful waiting for mild, asymptomatic Sadé grade I pockets; for symptomatic or severe (Sadé III-IV) pockets, it remains unclear which approach is better (Bayoumy et al., 2022).

During follow-up the audiologist records changes in hearing and middle ear pressure with regular audiometry and tympanometry. A steadily widening air-bone gap may indicate ossicular erosion and should be reported to the doctor. If a conductive loss is troublesome, a hearing aid can be fitted; it does not halt progression of the pocket, so ear examination and follow-up continue. Tracking Eustachian tube symptoms with a questionnaire gives the doctor additional information for treatment decisions.

Impact on quality of life and advice

Most retraction pockets do not affect daily life, but monitoring that may last for years can cause anxiety for patients and families. It is important to explain clearly what a pocket means, which signs need review and why follow-up matters. A mild conductive loss can make speech harder to follow in noise; in class, children benefit from sitting near the front with the better ear towards the teacher.

Practical advice: keep your follow-up appointments even without symptoms and, if possible, ask for your examination photographs to be kept. Nasal blockage, allergic rhinitis and frequent colds can impair Eustachian tube function, so plan their treatment with your doctor. Do not put cotton buds in your ear. If you have trouble equalising ear pressure when flying or diving, tell your doctor. If you notice discharge, a foul smell or a clear drop in hearing, seek review without waiting for your appointment.