Evidence supporting functional rhinoplasty or nasal valve repair: A 25-year systematic review. 
To systematically review the existing literature supporting the efficacy of modern-day rhinoplasty techniques for treatment of nasal obstruction due to nasal valve compromise.  PubMed search of the English-language literature from January 1982 to August 2007 combined with manual review of citations within article bibliographies.  A systematic review of the literature for the targeted objective was conducted.  Citations acquired from the targeted search were filtered and primary articles were reviewed to abstract information including interventions and outcome measures.  Articles were then assigned level-of-evidence grades as defined by the Oxford Centre for Evidence-Based Medicine.  A total of 861 citations were generated and 291 abstracts were identified as potentially relevant articles.  Of these abstracts, 82 articles merited full-text review.  A total of 44 articles met inclusion criteria.  The majority of the studies were classified as level 4 evidence, and only two studies met level 2b criteria.  There was considerable variation in the quality of the studies within the level 4 category.  All articles generally supported the effectiveness of functional rhinoplasty techniques for treatment of nasal obstruction.  There is substantial level 4 evidence to support the efficacy of modern-day rhinoplasty techniques for treatment of nasal obstruction due to nasal valve collapse.  More recent studies have incorporated validated patient-reported outcome measures, with more rigorous statistical analysis.  Future study design improvements include the use of comparison cohorts and incorporating standardized objective outcome measures.