Tympanostomy tube obstruction related to ototopical drug therapy.

Abstract

Obstruction of tympanostomy tubes is a potentially significant complication, sometimes requiring replacement of the nonfunctioning tube. Early blockage can occur secondary to bleeding during the tube placement procedure. Delayed obstruction is usually caused by inspissated secretions or epithelial casts. We briefly report our treatment of 9 cases of delayed ventilation tube obstruction that were associated with the use of an ototopical antibiotic/steroid suspension.

Introduction

Complications of tympanostomy tube placement include bleeding, otorrhea, persistent tympanic membrane perforation, tube extrusion, and tube obstruction. Of all these complications, only tube obstruction has not been widely addressed in the literature. In this article, we briefly discuss 9 cases of ventilation tube obstruction associated with the use of an ototopical antibiotic/steroid suspension.

Summary of cases

Between January 2004 and March 2005, we encountered 9 patients who had experienced tympanostomy tube obstruction within 1 week of starting ototopical therapy with the fixed-combination ototopical suspension ciprofloxacin/dexamethasone. All patients had been using these drops to treat episodes of acute otitis media with otorrhea. In each case, tube blockage had been noted during the first follow-up visit after the initiation of therapy. The obstructions had been caused by white concretions in the lumen of the tubes (figure, A). The appearance of these concretions was different from that of the usual casts that are seen in patients with inspissated mucus in the lumen of their tubes.

[FIGURE OMITTED]

In 4 of the patients, irrigation with a mixture of half-strength vinegar and water was sufficient to clean the tube and restore patency. Another 3 patients experienced tube clearing after they were switched to of loxacin otic solution. The remaining 2 patients required tube replacement when patency could not be reestablished; when the tubes were removed, more concretions were visible through the myringotomy defect in the middle ear space (figure, B).

Discussion

In the literature, tube obstruction is the least-discussed complication of tympanostomy tube insertion. Blockage can occur during the early postoperative period or later--for example, with the onset of an episode of otitis media. It is believed that most cases of early obstruction are caused by the clotting of blood within the lumen of the tube from the free edges of the tympanic membrane or by trauma to the skin of the ear canal. (1,2) Meticulous myringotomy technique and proper hemostasis have been advised to minimize the risk of this complication. Jamal reported that the risk of obstruction can also be lowered by instilling xylometazoline drops at the completion of the procedure. (1) Other methods, such as coating tubes with antibiotics, have been less successful. (3)

Delayed obstruction is usually caused by an accumulation of viscous secretions or epithelial debris around the tube. (2) Reid et al studied the composition of obstructing material in Shah tympanostomy tubes and found that it was made up of an eosinophilic coagulum that contained a polymorphonuclear leukocyte infiltrate, erythrocytes, and some gram-positive cocci. (4) They also found a definite association between tube blockage and the presence of thick fluid in the ear.

The size of a tympanostomy tube also appears to affect the rate of obstruction. Reid et al reported that short, wide-bore tubes are less likely to become blocked. (4) Mills et al found a definite relationship between tube size and the ease of penetration of ototopical medications. (5)

Obstruction of tympanostomy tubes by concretions of ototopical medications has not been previously reported. The antibiotic/steroid combination implicated in these 9 cases is made up of 0.3% ciprofloxacin and 0.1% dexamethasone. It is relatively more viscous than other topical medications on the market. It also has a tendency to form concretions which, when they precipitate in the lumen of a tube, can result in blockage. The actual incidence of tube concretions associated with ciprofloxacin/dexamethasone is unknown; even in our own practice, it is difficult to determine the number of patients who are prescribed various medications. The manufacturer of ciprofloxacin/dexamethasone reports that the rate of precipitation is less than 1%, (6) but such events appear to be more common with this suspension than with ototopicals in solution form. Indeed, we have not yet encountered any such concretions with other ototopicals, and we even used ototopical ofloxacin to reestablish patency in 3 of our patients. We have also used topical ofloxacin to clear tube obstructions related to inspissated secretions following episodes of otitis media with otorrhea.

References

(1.) Jamal TS. Avoidance of postoperative blockage of ventilation tubes. Laryngoscope 1995;105(8 Pt 1):833-4.

(2.) Jassar P, Jose J, Homer JJ. Otic drops used to clear a blocked grommet: An in vitro prospective randomized controlled study with blinded assessment. Clin Otolaryngol Allied Sci 2004;29:602-5.

(3.) Cunningham MJ, Harley EH, Jr. Preventing perioperative obstruction of tympanostomy tubes: A prospective trial of a simple method. Int J Pediatr Otorhinolaryngol 1991;21:15-20.

(4.) Reid AP, Proops DW, Smallman LA. Why do tympanostomy tubes block? Clin Otolaryngol Allied Sci 1988;13:279-83.

(5.) Mills RP, Albizzati C, Todd AS. Ear drops and grommets. Clin Otolaryngol Allied Sci 1990; 15:315-19.

(6.) Alcon Laboratories. Ciprofloxacin/dexamethasone prescribing information. Fort Worth, Tex.

From the Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of North Carolina at Chapel Hill.

Reprint requests: Marc K. Bassim, MD, G0412 Neurosciences Hospital, Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599. Phone: [phone]; fax: [phone]; e-mail: [e-mail]