Roya Azadarmaki1, John P Gaughan, Glenn Isaacson. 1. Departments of Otolaryngology-Head and Neck Surgery, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
Abstract
OBJECTIVES/HYPOTHESIS: It has been assumed that prolonged retention of tympanostomy tubes was random, with an incidence of 4% to 12% per tube. We have noticed patterns of tube retention that suggested a genetic predilection. We undertook this study to validate or disprove this impression. Such information may shed light on the physiology of tube extrusion and may help better define the risks of tympanostomy tube placement. STUDY DESIGN: Retrospective, single-surgeon, statistical analysis. METHODS: A computerized database of approximately 10,000 pediatric otolaryngology patients was queried. We identified all children treated by the senior author during a 6-year period who underwent tube removal for failed extrusion 24 or more months after placement. Siblings with retained tubes and individuals requiring bilateral tube removal were further analyzed: 1) using the law of multiplication of independent factors, the chance of retaining tubes in both ears of an individual was compared with the observed rate of bilateral retention by calculating the difference in Poisson rates; 2) the rate of siblings who retained one or both tubes was compared with nonsiblings who retained one or both tubes using the Z test for independent proportions. RESULTS: The observed rate of bilateral retention (228/6,000 = 0.038) far exceeded the theoretical rate (0.068 = 0.0046; P < .001). Siblings were more likely to retain tubes than nonsiblings (difference = 0.042; P = .085). This difference was more pronounced in unilateral (difference = 0.048; P = .014) than in bilateral retention (difference = 0.005; P = .856). CONCLUSIONS: Tympanostomy tube retention is not a random occurrence. Patterns of nonextrusion in individuals and siblings suggest a genetic mechanism. Implications for patient counseling and research are discussed.
OBJECTIVES/HYPOTHESIS: It has been assumed that prolonged retention of tympanostomy tubes was random, with an incidence of 4% to 12% per tube. We have noticed patterns of tube retention that suggested a genetic predilection. We undertook this study to validate or disprove this impression. Such information may shed light on the physiology of tube extrusion and may help better define the risks of tympanostomy tube placement. STUDY DESIGN: Retrospective, single-surgeon, statistical analysis. METHODS: A computerized database of approximately 10,000 pediatric otolaryngologypatients was queried. We identified all children treated by the senior author during a 6-year period who underwent tube removal for failed extrusion 24 or more months after placement. Siblings with retained tubes and individuals requiring bilateral tube removal were further analyzed: 1) using the law of multiplication of independent factors, the chance of retaining tubes in both ears of an individual was compared with the observed rate of bilateral retention by calculating the difference in Poisson rates; 2) the rate of siblings who retained one or both tubes was compared with nonsiblings who retained one or both tubes using the Z test for independent proportions. RESULTS: The observed rate of bilateral retention (228/6,000 = 0.038) far exceeded the theoretical rate (0.068 = 0.0046; P < .001). Siblings were more likely to retain tubes than nonsiblings (difference = 0.042; P = .085). This difference was more pronounced in unilateral (difference = 0.048; P = .014) than in bilateral retention (difference = 0.005; P = .856). CONCLUSIONS: Tympanostomy tube retention is not a random occurrence. Patterns of nonextrusion in individuals and siblings suggest a genetic mechanism. Implications for patient counseling and research are discussed.