DISCUSSION
The principal finding of this literature review was that PNN is a safe
procedure with an acceptable complication rate. It appears to be an
effective procedure for patients with allergic and non-allergic rhinitis
but the level, quality, and heterogeneity of the published evidence
hampers the strength of the conclusions that can be drawn. Every study
but one reported symptom improvement in patients undergoing PNN. Outcome
measures were largely valid and improvements were observed in all
individual nasal symptoms (particularly sneezing and rhinorrhoea) as
well as QoL measures, but most studies did not have a control arm.