Local side effects
Three patients in group A and two patients in group B refused repeated intratympanic injection due to unbearable pain. Twenty patients in the two groups complained of obvious transient vertigo after IT injection, but none of these patients terminated treatment. There were no cases of apparent bleeding, external otitis, otitis media or perforation of the tympanic membrane.
Recovery of overall hearing
The total hearing improvement at the long-term test point (D90) after admission was 31.0±9.64 dBHL in group A and 29.4±9.18 dBHL in group B. An effective rate of hearing improvement ≥15 dB was noted in 43 of the 49 patients in group A (87.8%) and 42 of the 49 patients in group B (85.7%). There were no significant differences between the two groups(Table 3).
Recovery of hearing loss atlow-mid frequencies
On day 7 (D7), the average 3-frequency PTA (250, 500, and 1000 Hz) value was 34.10±9.14 dBHL in group A and 25.70±6.88 dBHL in group B. Hearing recovery was better in group A than group B, and statistical comparison of the two groups by a t test (P<0.05) showed a significant difference between intratympanic dexamethasone(group A) and intravenous dexamethasone(group B). On days 13, 24 and 90 (D13, D24, D90), the average PTA values were 39.55±7.03, 42.15±6.65, and 42.70±6.57 dBHL in group A and 35.05±6.35, 41.85±5.38, and 42.20±5.12 dBHL in group B, respectively; there were no significant differences between group A and group B (P>0.05). The results showed rapid hearing recovery at low and mid frequencies in group A, and intratympanic plus intravenous dexamethasone in group B showed the same long-term efficacy with group A at the 90-day follow-up(Figure 1).
Recovery of hearing loss athigh frequencies
On day 7 (D7), the hearing improvement for the average 3-frequency PTA (2000, 4000, and 8000 Hz) value was 9.75±3.26 dBHL in group A and 8.85±2.93 dBHL in group B (P>0.05); thus, there was no significant difference between groups in hearing recovery at high frequencies. On D13, D24 and D90, the hearing improvements at average high frequencies were 18.90±5.72, 20.95±5.50, and 21.75±5.95 dBHL in group A and 17.35±4.87, 19.80±6.18, and 20.55±6.19 dBHL in group B. Group A exhibited better hearing improvement (21.75±5.95 dBHL) than in group B (20.55±6.19 dBHL), but the difference between groups was not significant (P<0.05). intratympanic dexamethasonemay lead to better hearing recovery at high frequencies than intravenous dexamethasone, but the difference was not significant in this study (Figure 2).