An observational, retrospective study was completed to compare the results of the PACIENA clinical trial (using the modified McIndoe technique) with a historical control group of nine patients who were operated on at San Juan University Hospital (1992–2015) using the classic technique. The PACIENA clinical trial included seven patients with vaginal agenesis who were operated on at two reference sites (May 2017–May 2018) using a neovaginal polylactic acid (PLA) prosthesis (PACIENA® prosthesis) and avoiding the use of a skin graft. The results illustrate a reduction in the length of surgery, 86.43 ± 4.75 min in the group with no skin graft compared to 155.56 ± 28.44 in the control group (p < 0.05); and reduction in the length of hospitalization time. Differences were also registered in the length of the neovagina, the average being 8.93 ± 1.42 cm for cases and 6.56 ± 1.13 cm for controls, with no differences in neovaginal epithelialization times or in the satisfaction of sexual relations occurring between groups. The modification of the classical McIndoe technique using the neovaginal PACIENA® prosthesis appears to be successful, obtaining good clinical results with shorter surgery and hospitalization times.