The establishment of a 3D anatomical coordinate system for defining vaginal axis and spatial position

Vaginal morphology and position associated with prolapse recurrence after vaginal surgery: A secondary analysis of the DEMAND study

OBJECTIVE

To identify vaginal morphology and position factors associated with prolapse recurrence following vaginal surgery.

DESIGN

Secondary analysis of magnetic resonance images (MRI) of the Defining Mechanisms of Anterior Vaginal Wall Descent cross-sectional study.

SETTING

Eight clinical sites in the US Pelvic Floor Disorders Network.

POPULATION OR SAMPLE

Women who underwent vaginal mesh hysteropexy (hysteropexy) with sacrospinous fixation or vaginal hysterectomy with uterosacral ligament suspension (hysterectomy) for uterovaginal prolapse between April 2013 and February 2015.

METHODS

The MRI (rest, strain) obtained 30-42 months after surgery, or earlier for participants with recurrence who desired reoperation before 30 months, were analysed. MRI-based prolapse recurrence was defined as prolapse beyond the hymen at strain on MRI. Vaginal segmentations (at rest) were used to create three-dimensional models placed in a morphometry algorithm to quantify and compare vaginal morphology (angulation, dimensions) and position.

MAIN OUTCOME MEASURES

Vaginal angulation (upper, lower and upper-lower vaginal angles in the sagittal and coronal plane), dimensions (length, maximum transverse width, surface area, volume) and position (apex, mid-vagina) at rest.

RESULTS

Of the 82 women analysed, 12/41 (29%) in the hysteropexy group and 22/41 (54%) in the hysterectomy group had prolapse recurrence. After hysteropexy, women with recurrence had a more laterally deviated upper vagina (p = 0.02) at rest than women with successful surgery. After hysterectomy, women with recurrence had a more inferiorly (lower) positioned vaginal apex (p = 0.01) and mid-vagina (p = 0.01) at rest than women with successful surgery.

CONCLUSIONS

Vaginal angulation and position were associated with prolapse recurrence and suggestive of vaginal support mechanisms related to surgical technique and potential unaddressed anatomical defects. Future prospective studies in women before and after prolapse surgery may distinguish these two factors.

The feasibility of uterine-vaginal axis MRI-based as evaluation of surgical efficacy in women with pelvic organ prolapse

Background

The aim of this study was to provide a potential surgical efficacy assessment in the treatment of pelvic organ prolapse (POP).

Methods

A retrospective cohort study was performed on magnetic resonance imaging (MRI) imaging data of 16 non-prolapsed (control group) and 30 preoperative and postoperative POP (case group) women from 2019 to 2021 at the First Affiliated Hospital of Kunming Medical University. MRI diagnoses and measures of the relevant anatomical points at rest were used to analyze the healthy control data and the data from POP women before and after surgery.

Results

The middle vaginal-PICS line angle (78.12°±15.03° vs. 69.35°±11.51°, 78.12°±15.03° vs. 61.56°±9.58°, P<0.05) and the middle-lower vaginal angle (179.30°±12.96° vs. 161.73°±10.42°, 179.30°±12.96° vs. 147.01°±12.20°, P<0.05) in the preoperative group were significantly larger than those in the control and postoperative groups. Y-axis coordinates of the endocervical orifice (−52.39±15.63 vs. −59.04±11.49 mm, −52.39±15.63 vs. −65.27±7.25 mm, P<0.05), posterior vaginal fornix (−34.25±13.30 vs. −46.69±11.09 mm, −34.25±13.30 vs. −49.93±8.02 mm, P<0.05), the junction of the middle and lower vagina (−0.48±8.65 vs. −11.34±7.33 mm, −0.48±8.65 vs. −10.11±9.77 mm, P<0.05), and anterior vaginal fornix (−23.14±13.71 vs. −34.68±9.07 mm, −23.14±13.71 vs. −38.64±6.48 mm, P<0.05), as well as the x-axes of the junction of the middle and lower parts of the vagina (26.79±6.71 vs. 19.56±5.24, 26.79±6.71 vs. 17.67±5.81, P<0.05), and vaginal introitus (23.39±7.12 vs. 18.55±4.22, 23.39±7.12 vs. 19.00±4.55, P<0.05) in the preoperative group were smaller than those of the control and postoperative groups. Differences between the control and postoperative groups were not statistically significant (P>0.05).

Conclusions

The current study established that the uterine-vaginal axis of POP women moved backward and downward in the coordinate system, as shown on MRI sagittal images. Further, it moved forward and upwards after surgical repair and more closely resembled that of the control group. The uterine-vaginal axis may provide an evaluation of surgical efficacy in women with POP.