ABSTRACT
This study was designed to compare the results of transtympanic iontophoresis of two different concentrations of dexamethasone into the middle ear to evaluate iontophoresis as a new method in management of SOM. The study group consisted of 70 patients [140 ears]. The mean age was 4.8 years + 1.39. All the patients had bilateral tympanogram type B, and MHL >20 dB at the start of the study. The patients were classified into the following groups: Group 1 [10 patients received saline solution iontophoresis in one ear/6 trials], group 2 [a- 30 patients received 0.4% dexamethasone in one ear/6 trials and b- 10 out of the 30 patients who continued iontophoresis for 10 trials], and group 3 [a- 30 patients received 0.8% dexamethasone in one ear/6 trials and b- 10 out of the 30 patients who continued iontophoresis for 10 trials]. All the patients received oral amoxicillin 40 g/kg/day/10 days. It started at the first day of iontophoresis. All received iontophoresis in one ear for 6 trials. Patients of groups 2b and 3b continued 10 trials. Each iontophoresis trials lasted 16 minutes. The iontophoresis was performed 3 times/week. The diagnosis was confirmed before and after iontophoresis by otoscopic examination and Siegle's pneumatic otoscopy, examination with operating microscope, hearing tests [pure tone audiometry, speech reception threshold [SRT] and tympanometry]. The tympanoaudiometric criteria for improvement were a gain in MHL of >15 db, or a change in tympanogram type from B to either A or Cl. The study showed a statistically significant gain in the iontophoresis ears when compared to the ears on the other side or those received saline [control group]. The mean gain in MHL was 11.43 dB in group 2A [0.4% dexamethasone] and 13.97 dB in group 3A [0.8% dexamethasone], compared to 6.5 dB and 6.6 dB on the other ears, respectively, or to 6 dB gain of saline iontophoresis ears. The study showed also a high correlation between SRT and MHL, which means that SRT can be used to monitor the progress of hearing instead of pure tone audiometry in young and uncooperative children. Iontophoresis of dexamethasone improved the tympanometric values of the treated ears. 26.7% of ears treated with 0.4% dexamethasone and 53.3% of ears treated with 0.8% dexamethasone have changed from type B to either A or Cl, in comparison to 10% and 13.3% in the other ears, respectively. The study showed also that increasing the concentration of dexamethasone from 0.4% to 0.8% has improved the audiometric and tympanometric results. The mean MHL gain was 13.97 dB in 0.8% group have changed to A or Cl, in comparison to 26.7% in 0.4% group. This effect is obvious when the tympanoaudiometric results of both groups were compared. While, the tympanoaudiometric results of group 0.4% were statistically insignificant, those of 0.8% group were found to be statistically significant. This showed clearly that increasing the concentration increases the improvement tympanoaudiometric results of SOM. Increasing the number of iontophoresis trials was shown to increase the improvement in the mean MFIL gain. In group 2B [10 trials 0.4% dexamethasone], the overall mean MHL gain alter the 10 trials was 17.3 dB compared to 9.4 dB after the initial six trials. In group 3B [10 trials 0.8% dexamethasone], the results were 21 dB and 14.5 dB, respectively. This increase in the mean MHL gain was statistically significant in both the group 2B and 3B. While, these patients had a statistically significant gain in the mean MHL, yet the improvement in their tympanometric results was lower than that of the patients who got 6 trials only