A new absorbable pressure-equalizing tube.

Objective: We investigated pressure-equalizing (PE) tubes made of biodegradable, absorbable material in an animal model.

Methods: PE tubes, made of poly-bis(ethylanate)phosphazene (PBE) were inserted in 55 ears of 28 Hartley guinea pigs, with survival times of 10, 30, and 60 days after tube insertion. In vivo reactions between the PBE-PE tube and the tympanic membrane (TM) were studied. Tubes, TMs, and middle ears were examined by scanning electron microscopy and light microscopy.

Results: There was neither infection nor an inflammatory reaction to the tube within the middle ear in any animal. At 30 days, 53% of the tubes had disintegrated. At 60 days, tubes were still functioning in the 25% of ears.

Conclusion: More research must be performed before these new PBE PE tubes can be considered for clinical use. Nonetheless, these tubes are promising. The disintegration rate can be controlled by varying the formulation of the polymer, so treatment can be adjusted to the needs of each patient.