Tympanosclerosis and mini grommets: the relevance of grommet design

Af, Dingle; Lm, Flood; Bu, Kumar; Rc, Newcombe

doi:10.1017/s0022215100131688

Cited by 11 publications

(13 citation statements)

References 18 publications

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“…7 It appears that in OME ventilation tubes do not protect the ears against the long-term development of attic retraction or cholesteatoma, and there is no long-term audiological bene t. [3][4][5]7 On the contrary the insertion of ventilation tubes can itself cause complications such as tympanosclerosis, otorrhoea and persistent perforation, the extent of which depend on the particular design and duration of the ventilation tube. [8][9][10][11] In our survey ve per cent of otolaryngologists in group B gave repeated infection caused by ventilation tubes to be a reason for prescribing hearing aids. If ventilation tubes cannot prevent middle-ear complications, but can cause additional problems, why should ventilation tubes be re-inserted if OME recurs after the initial insertion of the ventilation tube along with surgical attention to possible predisposing factors such as adenoidectomy?…”

Section: Discussionmentioning

confidence: 70%

Hearing aids versus ventilation tubes in persistent otitis media with effusion: a survey of clinical practice

et al. 2001

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A postal survey was carried out to determine the current clinical practice amongst consultant otolaryngologists in the UK, regarding re-insertion of ventilation tubes or recommendation of hearing aids in cases of recurrence of otitis media with effusion (OME) after ventilation tube extrusion. Amongst the 319 respondents, 15 (4.70 per cent) routinely, 146 (45.77 per cent) sometimes, and 158 (49.53 per cent) either never, or very rarely, recommend hearing aids. Hearing aids and ventilation tubes were both suggested to be equally good options by some consultants but they preferred surgery for a number of reasons. There were inconsistencies in practice and some of the reasons for re-inserting ventilation tubes are not evidence-based. A hearing aid is a non-invasive option and this survey shows a need for a randomized control trial of hearing aids and ventilation tubes in the management of persistent and recurrent OME.

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Section: Discussionmentioning

confidence: 70%

Hearing aids versus ventilation tubes in persistent otitis media with effusion: a survey of clinical practice

et al. 2001

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“…The duration in situ of the DT is defined as the time elapsed from insertion of the tube until the first follow‐up examination that showed extrusion of the tube. 4 Duration in situ is shown in Figure 2. Median duration in situ in the present study was 17 months (range, 1.5–36 mo).…”

Section: Resultsmentioning

confidence: 99%

A New Ventilation Tube for Long‐Term Middle Ear Ventilation

2002

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“…Comparing titanium and Teflon grommets of identical dimensions, Dingle et al . 5 found that retention times were, on average, 41 days greater for the titanium grommets. Hussain 6 also found very significant difference in extrusion rates for Shah ventilation tube (mean of 13.03 months) compared to the Shepard design (mean of 10.39 months) at 8‐month assessment.…”

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confidence: 92%

The effect of ventilation tubes on stresses and vibration motion in the tympanic membrane: a finite element analysis

et al. 1999

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Finite element analysis is used to determine the mechanical behaviour of structures. The deformation of a structure caused by a force can be calculated, and the stresses and strains within the component can be found. In brief, a geometric representation-a 'drawing'-of the structure is loaded into a computer, and a component is divided into 'elements' which usually have the shape of 'bricks'. A common analogy is a 'lego' brick assembly. The deformation of an element can be determined using engineering formulae, and the deformation of the whole structure can be determined when the elements are re-asssembled. There have been very few analyses of the biomechanical behaviour of ventilation tubes, or grommets, even though clinical studies have indicated that tube design and material determines extrusion rates and may influence tympanosclerosis. This paper reports a comprehensive biomechanical analysis of the effect of a grommet on the tympanic membrane. Analytical and computer simulation techniques (finite element analysis) are used to determine the changes in the vibratory motion and stresses in the membrane when a Reuter-Bobbin ventilation tube is inserted. It is found that the presence of a ventilation tube significantly affects the motion of the membrane in the neighbourhood of the implant. When the effect of implant material is investigated, it is found that the amplitude of motion of a heavier metal implant is less than a lighter polymeric implant. If it is true that higher motion predisposes towards early extrusion, then the lighter implant (polyethylene) is predicted to have a higher extrusion rate. Regarding the maximum stresses in the tympanic membrane, they form a crescent-shaped region in the anterior and posterior quadrants in the regions where tympoansclerosis is observed. The magnitude and pattern of the stress is predicted not to depend significantly on the presence of the tube. This suggests that tympanosclerosis is not determined by the implant per se and therefore that no tube design feature can be expected to prevent it.

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Tympanosclerosis and mini grommets: the relevance of grommet design

Cited by 11 publications

References 18 publications

Hearing aids versus ventilation tubes in persistent otitis media with effusion: a survey of clinical practice

Hearing aids versus ventilation tubes in persistent otitis media with effusion: a survey of clinical practice

A New Ventilation Tube for Long‐Term Middle Ear Ventilation

The effect of ventilation tubes on stresses and vibration motion in the tympanic membrane: a finite element analysis

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