Tri-dimensional model for ventilation tube permeability
- 100 Downloads
Ventilation tubes (VT) in the tympanic membrane expose the middle ear (ME) to the external auditory canal and its content. It carries the risk of penetration of contaminated material and could provide a pathway for the delivery of drugs into the ME. The aim of this study was to use a printed 3D-model of the external auditory canal (EAC) and ME to assess the permeability of various VTs to different fluids.
CT scan of the external and ME was 3D-reconstructed and printed. Five different types of VT were inserted in the model’s tympanic membrane and the minimal pressure for penetration to the ME was measured. Liquids with different viscosities, including commonly used ear drops, were tested.
Water passed through the standard 1.14 mm diameter VTs after filling the EAC with a volume of 2 ml and through a narrower grommet or a T-tube after filling the canal with 2.5 ml. Soapy-water had the highest penetration in all VTs (1–2 ml). The initial volume of dexamethasone needed for penetration was 2.5 ml in the standard tubes. It did not pass at any volume through the narrow grommet or the T-tube.
In the printed 3D-model, the volume of most solutions, including water, required to provide enough pressure in order to pass through the VTs was as high as the EAC volume or exceeded it. Soapy water had the highest penetrance while Dexamethasone needed volume of 2.5 ml to pass through the VT, questioning its reliability as a passive drug delivery channel to the ME.
KeywordsVentilation-tubes Three-D printing Otorrhea
There are no financial interests, arrangements or payments to disclose.
Compliance with ethical standards
Conflict of interest
There are no potential conflicts of interest to disclose.
Statement of human participants or animals
This research does not involve human participants or animals.
- 2.Goldstein NA, Mandel EM, Kurs-Lasky M, Rockette HE, Casselbrant ML (2005) Water precautions and tympanostomy tubes: a randomized, controlled trial. Laryngoscope 115:324–330. https://doi.org/10.1097/01.mlg.0000154742.33067.fb CrossRefPubMedGoogle Scholar
- 4.Rosenfeld RM, Schwartz SR, Pynnonen MA, Tunkel DE, Hussey HM, Fichera JS, Grimes AM, Hackell JM, Harrison MF, Haskell H, Haynes DS, Kim TW, Lafreniere DC, LeBlanc K, Mackey WL, Netterville JL, Pipan ME, Raol NP, Schellhase KG (2013) Clinical practice guideline: tympanostomy tubes in children. Otolaryngol Head Neck Surg (United States). https://doi.org/10.1177/0194599813487302 CrossRefGoogle Scholar
- 7.Pashley NR, Scholl PD (1984) Tympanostomy tubes and liquids—an in vitro study. J Otolaryngol 13:296–298. http://www.ncbi.nlm.nih.gov/pubmed/6544843
- 9.Hebert R, King G, Bent J (1998) Tympanostomy tubes and water exposure: a practical model. Arch Otolaryngol Head Neck Surg 124:1118–1121. http://archotol.jamanetwork.com/article.aspx?articleid=221069 CrossRefGoogle Scholar