Limitations
The study has several important limitations. Firstly, the retrospective nature of the data introduces significant source of selections bias. All the comparisons of outcomes between the treatment groups should be interpreted cautiously. While we attempted to assess and compare a number of possible sources of bias (time to surgery, size of collection etc.) between the groups, it is possible that some important factors were not accounted. Secondly, as it was a retrospective review, we were unable to extract the clinicians’ reasoning behind choosing one treatment strategy over another. Thirdly, small sample of patients treated with conservative and neurosurgery only approaches, prevents meaningful comparisons and risk type 2 error. The data on the individual procedures was provided, however subgroup analysis stratified by the type of sinus intervention was not feasible due to low patient numbers. Finally, no patient reported outcomes were collected.