Investigating Perineal Gap as a Novel Measure of Level III Pelvic Floor Support

Importance This study provides clinically useful data regarding the perineal gap (PG), a novel horizontal measure of the genital hiatus (GH), to better characterize GH and inform surgical restoration of normal GH support. Objectives The objectives of this study were to determine the correlation of PG and GH and calculate the association of posterior repair (PR) with the changes in PG and GH before and after PR (Aim 1) and validate intraoperative PG (Aim 2). Study Design Aim 1 was a retrospective study of women undergoing pelvic organ prolapse surgery with available Pelvic Organ Prolapse Quantification, PG, and GH measurements. Pre-PR and post-PR measurements were abstracted. Pearson correlation coefficients were calculated between PG and GH, and between the change in PG (ΔPG) and the change in GH (ΔGH) if a PR was performed. Linear regression assessed the effect of ΔPG on ΔGH. The prospective validation study (Aim 2) determined the correlation between resident and attending physician PG measurements. Results Among 126 patients included in Aim 1, 83% (n=105) underwent PR. The correlation between pre-PR GH and PG was 0.28 (95% CI, 0.08–0.45) and between pre-PR PG and maximal vaginal descent was 0.19 (95% CI, 0.01–0.36). Correlation between ΔPG and ΔGH was 0.38 (95% CI, 0.20–0.54); a 1 cm ΔPG was associated with a 0.18 cm ΔGH (95% CI, 0.09–0.27). Attending physician and resident PG values were strongly correlated (0.75; 95% CI, 0.66–0.82). The mean bias of PG was 0.07 (2SD±1.7). Conclusions At the time of PR, a 5 cm reduction in PG is associated with a 1 cm reduction in GH. Intraoperative PG demonstrates sufficient reproducibility and low bias.