The posterior compartment is measured similarly to the anterior compartment: the corresponding terms are Ap and Bp. The nine measurements can be recorded as a simple line of numbers (i.e., −3, −3, −8, −10, −3, −3, 11, 4, 3 for points Aa, Ba, C, D, Ap, Bp, total vagina length, genital hiatus, and perineal body, respectively). The six vaginal sites have possible ranges that depend on the total vaginal length (Table 27.1). After collection of the site-specific measurements, stages are assigned according to the most dependent portion of the prolapse (Table 27.2).
The POP-Q examination often appears confusing on initial review; however, a measuring device (i.e., a marked ring forceps or marked cotton-tip applicator) can assist in instructing those unfamiliar with this staging system. The POP-Q examination provides a standardized measurement system to allow for more accurate assessments of postoperative outcome and to ensure uniform, reliable, and site-specific descriptions of pelvic organ prolapse. There is interest in using the POP-Q examination to measure prolapse as a continuous variable rather than in stages because it would provide greater statistical power in clinical research (24). The American Urogynecology Society provides a video (25) that describes the POP-Q exam and demonstrates its use.
In a clinical setting, at least three measurements should be obtained: the most advanced extent of the prolapse in centimeters relative to the hymen that affects the anterior vagina, the posterior vagina, and the cervix or vaginal apex.
As noted previously, whether the older staging systems or the POP-Q system is used, it is important to document the most pertinent findings on examination. This will help in documenting the baseline extent of prolapse and the results of treatment.
Table 27.1 Possible Ranges of the Six Site-Specific Pelvic Organ Prolapse Quantitative Examination Measurements
TVL, total vaginal length. Adapted from Bump RC, Mattiasson A, Bo K, et al. The standardization of terminology of female pelvic organ prolapse and pelvic ﬂoor dysfunction. Am J Obstet Gynecol 1996;175:11–12, with permission.
Table 27.2 Stages of Pelvic Organ Prolapse
From Bump RC, Mattiassion A, Bo K, et al. The standardization of terminology of female pelvic organ prolapse and pelvic ﬂoor dysfunction. Am J Obstet Gynecol 1996;175:13, with permission.
Pelvic muscle function should be assessed during the pelvic examination. Following bimanual examination with the patient in the lithotomy position, the examiner can palpate the puborectalis and pubococcygeus muscles inside the hymen along the pelvic sidewalls at approximately the 4 and 8 o’clock positions. One can appreciate basal muscle tone and whether there is increased tone with contraction as well as strength, duration, and symmetry of contraction (26). A recto-vaginal examination should also be performed to assess basal and contraction muscle tone of the anal sphincter complex.