HYPOTHESIS: Our hypothesis is that @entity2266 media and @entity2346 media with effusion cause @entity2693 loss of the tympanic membrane. This loss of @entity2693 may be persistent and precede the development of retraction pockets and @entity3540 . BACKGROUND: Postinflammatory changes such as retraction pockets and @entity3540 develop in the pars flaccida and in the pars tensa of the tympanic membrane. In our previous experimental studies, @entity2693 changes were shown to develop early in the pars tensa in response to @entity2266 media and @entity2346 media with effusion. These changes are suggested to be precursors to a later development of retraction pockets and @entity3540 . In the clinical situation, retraction pockets are often found in the pars flaccida only. The aim of the current study was thus to investigate whether @entity2693 changes appear also in the pars flaccida during @entity2266 media. METHODS: @entity328 type 3 was injected into the middle ear to induce @entity2266 media. As a measure of pars flaccida @entity2693 , peak displacement versus middle ear pressure was used. The peak displacement measurements were obtained from full-field moir  ; interferometry, which is a noncontacting optical technique for deformation measurements. RESULTS: Ears with @entity2266 media showed increased peak displacement of the pars flaccida at a middle ear pressure of 200 daPa, compared with normal controls. CONCLUSION: There was a decreased mechanical @entity2693 of the pars flaccida in @entity697 media. This decreased @entity2693 may predispose for future retraction pocket formation and @entity3540 development.

Pars flaccida displacement pattern in XXXX media in the gerbil.

@entity697 :: ('MESH:D000208', 'Disease') :: ['acute purulent otitis'] @entity3540 :: ('MESH:D002781', 'Disease') :: ['cholesteatoma'] @entity2266 :: ('MESH:D010035', 'Disease') :: ['purulent otitis'] @entity328 :: ('1313', 'Species') :: ['Streptococcus pneumoniae'] @entity2346 :: ('MESH:D010031', 'Disease') :: ['otitis'] @entity2693 :: ('MESH:C566112', 'Disease') :: ['stiffness']
@entity2266 :: (MESH:D010035,Disease) :: ['purulent otitis']
