ABSTRACT: Importance:While extracorporeal septoplasty (ECS) and its modifications have been previously studied, to our knowledge, no systematic review of surgical outcomes and complications of this technique has been performed. Objective:To evaluate the evidence of surgical outcomes and complications of ECS (including modified techniques) to treat severe L-strut septal deviation defined as deviation within 1.0 cm of the caudal or dorsal septum. Data Sources:MEDLINE, Embase, CINAHL, CENTRAL, Scopus, and Web of Science databases and reference lists were searched from inception to April 2018 for clinical and observational studies. Search terms included extracorporeal, septoplasty, and septum. Study Selection:Selection criteria were defined according to the population, intervention, comparison, and outcome framework. Relevant studies were selected by 2 independent reviewers based on abstracts and full texts. Data Extraction and Synthesis:Data were extracted using standardized lists chosen by the authors according to Cochrane Collaboration guidelines. Data were collected and synthesized with ranges reported, as well as assessment of bias and heterogeneity when applicable. Analysis started in February 2019. Main Outcomes and Measures:Outcomes assessed included functional nasal airway improvement by objective measurements and subjective measurements (Nasal Obstruction Symptom Evaluation [NOSE] and visual analog scale scores); complications including bleeding, infection, dorsal irregularities, and other functional or cosmetic deficits; and as revision surgery rates. Results:Of 291 records initially obtained, 31 were considered relevant after review according to PRISMA guidelines. All studies except 1 randomized clinical trial (3.2%) were observational in nature, with 21 retrospective studies (67.7%) and 9 prospective studies (29.0%). Conventional ECS was performed in 16 studies (51.6%), and modified ECS was performed in 15 studies (48.4%). The sample size varied from 10 to 567, and the mean age varied from 22.5 to 46 years. Of 31 studies, 14 (45%) were of good methodology. Meta-analysis was performed on 5 studies reporting change in NOSE scores, with pooled effect of -60.0 (95% CI, -67.8 to -52.2) points, but heterogeneity was high, with I2?=?96%. When comparing complications between modified and conventional ECS, the relative risk for infections was 0.95 (95% CI, 0.34-2.7); for bleeding, 0; for nasal dorsal irregularities, 0.29 (95% CI, 0.16-0.53); for other cosmetic complications, 4.3 (95% CI, 0.87-21.1); for other functional complications, 0.47 (95% CI, 0.20-1.1); and for revision operations, 1.4 (95% CI, 0.83-2.3). Conclusions and Relevance:Of the 31 studies included in this systematic review, less than half were of good methodology, and a significant level of heterogeneity was found regarding type of outcome measure used and reporting of complications. To improve the level of evidence, better study methodology, standardization of surgical outcomes measures, and reporting of complications are needed.