Article
Effects of pressure load during train ride after stapedotomy – case study
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Published: | July 22, 2009 |
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Outline
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After a stapedotomy with insertion of a Soft CliP (H. Kurz, Dusslingen), a patient showed good postoperative results like normal. He was discharged after 4 days and traveled home with an InterCity Express (ICE). After that his hearing capabilities changed for the worse but could be improved reproducibly by valsalva manoeuvres. In a revision surgery the Soft CliP was resected and a K-Piston inserted. The revision surgery showed no indication for a failed reconstruction. Postoperative results looked again good like normal. He was discharged from hospital after 2 days and traveled home with an InterCity (IC). Now all following examinations showed improved and stabilized hearing capabilities.
Hypothesis: Due to pressure variations during train ride the tympanic membrane was dislocated.
Pressure measurements have been conducted in an Inter City Express (ICE) and an Inter City (IC) (see Figure 1 [Fig. 1]). It turned out that during a train ride in the ICE, the passenger is exposed to a high number of pressure variations at considerable high mean levels. It seems likely that the high number of load cycles around high mean levels caused a microslip zone between the tympanomeatal flap and the ear canal wall. This area enlarged with increasing number of load cycles finally leading to an overall dislocation of the tympanomeatal flap. As a consequence, the tympanic membrane was not properly stretched, but partially slack which caused the observed hearing loss.
It can be recommended that for some time after the operation, patients should avoid situations in which higher pressure variations can occur, i.e. like flying, diving, slashing a car door and so on. In particular one should avoid situations with a high number of load cycles like travelling in an ICE.
References
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- Glöckle H. Tunnelaerodynamik im Hochgeschwindigkeitsverkehr. Eisenbahntechnische Rundschau 1996;45(9):563-6.