GH + PB and its role in prolapse, prolapse progression and surgery planning.

Firstly, lets define some things:

 *Genital Hiatus (GH) is a measurement taken from the middle of the external urethral meatus to the posterior midline hymen

*Perineal Body (PB) is measured from the posterior margin of GH to the middle of the anal opening. 

The dimensions of the levator hiatus (LH) have been shown to be strongly correlated with signs and symptoms of Pelvic Organ Prolapse (POP) (1,2). A 2012 study by Khunda et al. found that GH + PB has the highest correlation with ultrasound assessment of levator hiatus, compared with GH or PB alone. Therefore, clinically, we can use the measurement of GH + PB to determine things like prolapse risk factors and progression.

Firstly, let’s just look at GH in isolation. A study in 2019 by Handa et al. concluded that a GH over 3cm represents a high risk of developing POP, suggesting that GH measurements may be able to predict the likelihood of POP development over a 5 to 10 year period before it develops. The study also found that if an individual’s GH is increasing by >0.5cm/5yr they are more likely to develop POP. Further to this they also found that POP at any point in time is increased 900% for women with a GH greater than or equal to 3.5 cm versus those with a GH less than or equal to 2.5 cm.

The Honda et al. study concluded that "Assessing GH may offer information relevant to POP risk and to women’s pelvic health. Our results suggest that health-care providers could consider monitoring not simply the current size of the GH but also the pattern of changes in GH over time. An increase of close to 0.5 cm in a 5-year period would be most typical of women observed to develop POP in the current study."

If we then look at GH + PB, what else can it tell us?

We know that the measurement of GH + PB is closely correlated with the levator hiatus (LH) dimensions as measured on ultrasound. The LH is the opening within the levator plate and research has shown a strong correlation between a wider LH and POP symptoms and progression. Hiatal ballooning is a term used to describe excessive movement and opening of the LH on Valsalva.

Below are GH + PB measurements and their corresponding level of hiatal ballooning (2,3):

• 7 cm = normal
• 7 - 7.99 = mild ballooning
• 8 - 8.99 = moderate ballooning
• 9 - 9.99 = marked ballooning
• >10 cm = severe ballooning.

** >8.5 cm is associated with levator avulsion

Clinical Application:

Taking someone’s GH + PB can give you information about the tone of their pelvic floor, the strength of their pelvic floor, and their likelihood of having a levator avulsion (>8.5cm). It can also be used as an outcome measure to track treatment such as success of pessary usage and pelvic floor muscle training and/or worsening prolapse and prolapse progression.

There is research to suggest that the use of a pessary over a 3-month period may decrease someone’s GH and therefore could be a useful tool if trying to decrease the levator hiatus and prevent prolapse progression (4).

Further, for surgery planning, a study in 2012 by Dietz et al suggests that GH may be a useful predictor in prolapse reoccurrence, particularly after an anterior repair (3,5). They suggested that the presence of a levator avulsion may increase the risk of surgical failure and therefore determining this clinically, via GH + PB and confirming via ultrasound, may assist with surgical decisions. They concluded that “Levator avulsion is associated with a relative risk of 3–4 for cystocele recurrence after anterior colporrhaphy. Levator assessment can identify patients at high risk of recurrence and may be useful as a selection criterion before mesh implantation.” (5).

Summary:

Taking measurements of GH and GH + PB can be useful in determining prolapse risk over time as well as a useful outcome measure to track treatment success, predict the likelihood of levator avulsion and as a tool to discuss surgical options with patients.

You can purchase our POPQ measuring sticks here. We have included a cheat sheet with norm values, ballooning measurements, as well as POP stages!

1. Handa, V. L., et al. (2019). "Longitudinal changes in the genital hiatus preceding the development of pelvic organ prolapse." American journal of epidemiology 188(12): 2196-2201.
2. Khunda, A., Shek, K. L., & Dietz, H. P. (2012). Can ballooning of the levator hiatus be determined clinically? American Journal of Obstetrics and Gynecology, 206(3), 246.e1–246.e4.doi:10.1016/j.ajog.2011.10.87
3. Gerges, B., Kamisan Atan, I., Shek, K. L., & Dietz, H. P. (2013).How to determine “ballooning” of the levator hiatus on clinical examination: a retrospective observational study. International Urogynecology Journal, 24(11), 1933–1937.doi:10.1007/s00192-013-2119-6
4. Jones K, Yang L, Lowder JL, Meyn L, Ellison R, Zyczynski HM, et al. Effect of pessary use on genital hiatus measurements in women with pelvic organ prolapse. Obstetrics & Gynecology. 2008;112(3):630-6.
5. Dietz, H. P., Chantarasorn, V., & Shek, K. L. (2010).Levator avulsion is a risk factor for cystocele recurrence. Ultrasound in Obstetrics and Gynecology, 36(1), 76–80.doi:10.1002/uog.7678