Strengths of study and comparisons with other studies
This study represents a real-world experience of SSNHL utilising salvage ITS therapy. The mean average threshold improvement post-ITS therapy of 2.9dB in this study is significantly lower than that expected based upon other studies. A control study in 2006 by Xenellis et al demonstrated that when ITS therapy was compared to a control group with no treatment, hearing was found to improve by 14.9 dB, compared with a deterioration of 0.8 dB in the control group, with the authors recommending ITS as a safe and effective treatment7.  A limited meta-analysis published by Spear et al (32 studies) revealed a mean improvement of 13.3 dB in the ITS salvage group versus placebo.5 Recent AAOHNS guidelines also state that the majority of studies following ITS do show improvement in hearing.3 All 5 of the RCT’s referenced used the latest AAOHNS recommended paradigm of at least 4 injections over 2 weeks, within 2-6 weeks of the onset of symptoms. This is a slightly accelerated protocol in comparison to the 3 injections over 3 weeks utilised in this study, mainly as it was based on guidance published prior to this recent 2019 update, perhaps contributing to the greater improvements in hearing recovery. The mean length of time in this study between the first oral steroid dose and the first ITS injection was 17.4 days.