title: A new absorbable pressure-equalizing tube.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Pediatric Otolaryngology, The Children's Hospital of Philadelphia, and the Institute of Photochemistry and High Energy Radiation, National Institute of Nuclear Energy, Legnaro, Padua, Italy. rderedita@hotmail.com
authors.forename: Riccardo
authors.initials: R
authors.lastname: D'eredità
authors.forename: Roger R
authors.initials: RR
authors.lastname: Marsh
authors.forename: Silvano
authors.initials: S
authors.lastname: Lora
authors.forename: Ken
authors.initials: K
authors.lastname: Kazahaya
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials; D006168:Guinea Pigs; D008876:Middle Ear Ventilation / Q000295:instrumentation*; D009943:Organophosphorus Compounds; D010034:Otitis Media with Effusion / Q000601:surgery*; D011897:Random Allocation; D016896:Treatment Outcome; D014432:Tympanic Membrane / Q000601:surgery*; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D009943:Organophosphorus Compounds