Anogenital Distance and Perineal Measurements of the Pelvic Organ Prolapse (POP) Quantification System

Summary

This manuscript describes the procedures to perform anogenital distance (AGD) and perineal measurements standardized by the Pelvic Organ Prolapse Quantification System (POP-Q): perineal body (PB) and genital hiatus (GH). These measurements are compared in women with and without pelvic organ prolapse.

Abstract

Anogenital distance (AGD) is a sexually dimorphic attribute, twice longer in males than in females, and a marker of intrauterine hormonal environment. Interest in AGD measurements is increasing due to mounting evidence on their potential clinical implications. A parallel set of perineal measurements, the Pelvic Organ Prolapse Quantification System (POP-Q), include similar, but not exactly the same, landmarks: the perineal body (PB) and the genital hiatus (GH) lengths. However, clinical reproducibility of both perineal measurements and their usefulness to describe perineal anthropometry needs to be elucidated. To our knowledge, there is no publication in video format showing the methodology of these measurements. The main objective of this work is to show how to properly perform perineal anthropometry, including measurements of the AGD in its two variants [anoclitoral (AGD_AC) and anofourchette (AGD_AF)], genital hiatus (GH) and perineal body (PB). Moreover, we explored if there were differences in these measurements in women with and without Pelvic Organ Prolapse (POP). We research whether the anthropometric characteristics of the perineum, such as AGD (which is determined prenatally), may be altered in these women and be an independent etiological factor for pelvic floor dysfunction. We show two different ways of measuring perineal lengths, as they might be quite comparable. Our suggestion is that unifying perineal measurements could be useful for clinical and biomedical investigation. More studies are needed in order to compare GH and PB measurements and its AGD counterparts to analyze which procedures are more reproducible with less intra and interobserver variability.

Introduction

Anogenital distance (AGD) is an easily accessible and noninvasive anthropometric measurement (Figure 1). AGD is a sexual dimorphism in placental mammals, being almost twice longer in males than in females. It is considered a marker of intra uterus hormonal environment^1,2. AGD has been related to prenatal exposure to endocrine disruptors^3,4,5 and androgens during critical periods of genital development^6,....

Protocol

This study was approved by the Ethics Research Committee of the University of Murcia. Written informed consent was obtained from all participants.

1. Perineum Measurements

NOTE: Before taking the measurements, two observers have to be trained to minimize inter-observer variability.

1. Patient Preparation
   1. Place the patient in a lithotomy position, with thighs at an angle of 45° to the examination table.
   2. Use a digital caliper with a resolution length of 0.000500 inches (Figure 2A).
   3. To begin measuring, close the device and....

Results

Fifty-eight patients were included. Previous studies in women have reported that the minimum AGD distances was 24 mm¹² with a standard deviation of about 10 mm¹². The minimum sample size to detect a significant difference between the groups with respect to AGD_AC (type I error α=0.05 and type II error β = 0.1) was estimated to be 25 individuals in each group (50 in total), based on a difference of at least 12 mm in AGD_AC.......

Discussion

The article shows the procedure to carry out the perineal measurements according to both the AGD concept and the POP-Q system. Both procedures are described with different measurement systems: the AGD measurement with calipers in millimeters, and the POP-Q measurement with a ruler in centimeters. It would be desirable to unify the measuring instruments and the accuracy of the methods, and not just the landmarks. This is of great importance, since the more reproducible a measure is, the more reliable it will be. That will.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Digital Caliper. Stainless Steel Digital Caliper	VWR International, LLC, West Chester, PA, USA	76181-562  OS ABS DIGTL CALIPER 500-171-30 STAIN	Absolute Digimatic Calipers, Stainless Steel, SPC, Accuracy +/-0.001in, Batt. Life 3.5 Years (20,000 hours), Display Type Digital LCD, Measurement Type ABS, Range 6in, Resolution (Length) 0.000500 in, Tip
Voluson E8	General Electric Healthcare
Sterile Utility Skin Marker and Ruler	Medline	DYNJSM06