Endoscopic posterior nasal neurectomy for intractable rhinitis: a systematic review of the literature Running Title: Endoscopic PNN: a systematic review

Objectives: Rhinitis affects up to 40% of the population worldwide and can significantly reduce quality of life. Some patients remain symptomatic despite maximal medical therapy. In refractory cases, posterior nasal neurectomy (PNN - the division of the intranasal nerve branches containing postganglionic parasympathetic fibres) is postulated to reduce symptom burden. The objectives of this paper were to review the literature to establish whether the procedure is effective and safe in the management of allergic and non-allergic rhinitis. Design: A systematic review of Pubmed, EMBASE and MEDLINE was undertaken. Studies were excluded if not available in English or undertaken in non-human subjects. Participants: Seventeen articles satisfied the inclusion criteria studying in total 2029 patients. Sample size ranged from 8-1056. Main Outcome Measures: Patient-reported objective and subjective outcomes and post-operative complications were reviewed Results: There were two randomised controlled trials, two case control studies, and the remaining thirteen were case series using both objective and subjective outcome measures. All but one study found improved patient reported outcomes following PNN. Complications were reported in 10 studies - haemorrhage was the most common complication and was observed in 28 patients (1.6% of subjects). Conclusions: Endoscopic posterior nasal neurectomy is safe and appears to be effective in the treatment of intractable rhinitis but the level of the available evidence was generally poor. Larger, well designed studies are needed to clarify its role in the management of difficult-to-treat rhinitis.