| Abstract: | In an effort to evaluate the safety and efficacy of the currently available polytetrafluoroethylene (PTFE)-membrane ventilation tube, in a group of 41 children, the experimental tube was inserted into one ear and a conventional tympanostomy tube was placed in the other ear. The membrane tubes, except in a few instances, were inserted into ears without effusion. After the procedure the children were forbidden to swim and their ears were protected during bathing. In addition to pneumatic otoscopy, a specially designed tympanometric test—which determined if the membrane tube was functioning—was used to assess the operation of the new device postoperatively. In many of the children, Eustachian tube function studies were also performed on the ears with the conventional tympanostomy tubes. The study was aborted early in the clinical trial period due to the early findings: only 10 of 41 (24%) of the membrane tubes continued to function, the remainder having become occluded; whereas 35 of 41 (85%) of the conventional tympanostomy tubes were found to be still functioning during the same period of observation. Twelve of the 41 membrane tubes had to be removed prematurely and replaced with conventional tympanostomy tubes due to recurrence of middle ear effusion. Scanning electron microscopic studies of the removed tubes revealed blockage of the membrane pores. From the extraordinarily high failure rate of the PTFE-membrane ventilation tube in this study, it is evident that the experimental tube should not replace the conventional tympanostomy tube at this time. The selection of the PTFE covering-membrane on this tube was ill advised, but the rationale of a semipermeable-membrane ventilation tube has merit. However, should another membrane ventilation tube be designed, its routine use must await controlled clinical trials to determine safety and efficacy in humans. |
