Factors Affecting the Extrusion Rate of Ventilation Tubes

OBJECTIVES: The objective of this study was to determine the various factors that affect the extrusion rate of ventilation tubes (VTs), including the nature of the middle ear effusion. METHODS: A retrospective chart review of 82 pediatric patients (177 ears) who received VT insertion surgery under general anesthesia was carried out to evaluate the relationship between various factors and the VT extrusion rate. The factors we analyzed included age, gender, the adenoid size, the amount and content of the middle ear effusion after myringotomy, bleeding events, associated adenoidectomy and the findings of the tympanic membrane status, the tympanometry and the audiometry of the air bone gap. RESULTS: The mean extrusion time was 254 days (range, 11 to 809 days). The patients with no history of previous VT insertion had a longer extrusion time (mean, 279 days) than did the patients who had undergone previous VT insertion (mean, 203 days). The patients with serous effusion had the shortest extrusion time (mean, 190 days) as compared to those patients with glue (273 days) and pus (295 days) effusions. Other factors had no statistical significant relationship with the extrusion time. CONCLUSION: The mean VT extrusion time was 254 days. The VT extrusion time was significantly related to the characteristics of the middle ear effusion and a history of previous VT insertion. Thus, the nature of middle ear effusion can provide a clinical clue to predict the VT extrusion time.

Clinical Investigation of Therapeutic Effect and Extrusion Rate of Punctal Plug for Dry Eye Syndrome

PURPOSE: To investigte the extrusion rate of punctal plugs and to evaluate their long-term effectiveness related to punctal occlusion. METHODS: The subjects were 120 eyes of 60 patients with tear-deficient dry eye who underwent punctal occlusion using a silicone punctal plug from May 2003 to Jun 2004. They were followed up for 382.3+/-164.3 days. We studied the extrusion rate and the period of extrusion for each plug and examined the differences between the objective and subjective indicators of dry eye syndrome before and after plug insertion and between extruded and non-extruded punctal plugs. RESULTS: In this study, 25.8% of all plugs were extruded during the follow-up period. The majority of plugs (41.9%) were extruded within 100 days after plug insertion. As objective indicators, results of Schirmer test and BUT were significantly increased after plug insertion. As subjective indicators, the patients' clinical symptoms significantly improved. Patient use of artificial tear drops significantly decreased and was discontinued by 70.8% after plug insertion. There were however no significant differences between the extrusion group and the non-extrusion group in each case. CONCLUSIONS: Punctal plug occlusion therapy for tear-deficient dry eye is effective, but the extrusion rate is relatively high. Regardless of punctal plug extrusion, patients experienced a symptomatic improvement. Serious consideration of this fact may greatly aid in making therapeutic adaptations and maintaining a good relationship.