Objective We sought to identify and summarize definitions of apical support loss utilized for inclusion, success, and failure in surgical trials for treatment of apical vaginal prolapse. Background Pelvic organ prolapse is a common condition affecting more than 3 million women in the US, and the prevalence is increasing. Prolapse may occur in the anterior compartment, posterior compartment or at the apex. Apical support is considered paramount to overall female pelvic organ support, yet apical support loss is often under recognized and there are no guidelines for when an apical support procedure should be performed and/or incorporated into a procedure designed to address prolapse. Study Design A systematic literature search was performed in 8 search engines: PubMed 1946-, Embase 1947-, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Review Effects, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov , Proquest Dissertations and Theses, and FirstSearch Proceedings, using key words for apical pelvic organ prolapse and apical suspension procedures through April 2016. Searches were limited to human beings using human filters and articles published in English. Study authors (M.R.L.M., J.L.L.) independently reviewed publications for inclusion based on predefined variables. Articles were eligible for inclusion if they satisfied any of the following criteria: (1) apical support loss was an inclusion criterion in the original study, (2) apical support loss was a surgical indication, or (3) an apical support procedure was performed as part of the primary surgery. Results A total of 4469 publications were identified. After review, 35 articles were included in the analysis. Prolapse-related inclusion criteria were: (1) apical prolapse (n = 20, 57.1%); (2) overall prolapse (n = 8, 22.8%); or (3) both (n = 6, 17.1%). Definitions of apical prolapse (relative to the hymen) included: (1) apical prolapse >–1 cm (n = 13, 50.0%); (2) apical prolapse >+1 cm (n = 7, 26.9%); (3) apical prolapse >50% of total vaginal length (–total vaginal length/2) (n = 4, 15.4%); and (4) cervix/apex >0 cm (n = 2, 7.7%). Sixteen of the 35 studies (45.7%) required the presence of symptoms for inclusion. A measurement of the apical compartment (relative to the hymen) was used as a measure of surgical success or failure in 17 (48.6%) studies. Definitions for surgical success included: (1) prolapse stage >2 in each compartment (n = 5, 29.4%); (2) prolapse >–total vaginal length/2 (n = 2, 11.8%); (3) apical support >–total vaginal length/3 (n = 1, 5.9%); (4) absence of prolapse beyond the hymen (n = 1, 5.9%); and (5) point C at ≥–5 cm (n = 2, 11.8%). Surgical failure was defined as: (1) apical prolapse ≥0 cm (n = 2, 11.8%); (2) apical prolapse ≥–1 cm (n = 2, 11.8%); (3) apical prolapse >–total vaginal length/2 (n = 3, 17.6%); and (4) recurrent apical prolapse surgery (n = 1, 5.9%). Ten (28.6%) of the 35 studies also included symptomatic outcomes in the definition of success or failure. Conclusion Among randomized, controlled surgical trials designed to address apical vaginal support loss, definitions of clinically significant apical prolapse for study inclusion and surgical success or failure are either highly variable or absent. These findings provide limited evidence of consensus and little insight into current expert opinion.