ICS 1999, Denver
Consensus reports - Standardisation Committee Reports
The Standardization of Terminology of Lower Urinary Tract Function Recommended by the International Continence Society

P. Abrams, J.G. Blaivas, S.L. Stanton and J.T. Andersen (Chairman)
ICS Committee on Standardization of Terminology
Copyright c International Urogynecology Journal. Springer-Verlag London Limited, UK and the International Continence Society. Reprinted with permission.

The Standardization of Terminology of Female Pelvic Organ Prolapse and Pelvic Floor Dysfunction

1 INTRODUCTION

The International Continence Society (ICS) has been at the forefront in the standardization of terminology of lower urinary tract function since the establishment of the Committee on Standardization of Terminology in 1973. This committee's efforts over the past two decades have resulted in the world-wide acceptance of terminology standards that allow clinicians and researchers interested in the lower urinary tract to communicate efficiently and precisely. While female pelvic organ prolapse and pelvic floor dysfunction are intimately related to lower urinary tract function, such accurate communication using standard terminology has not been possible for these conditions.

There is no universally accepted system for describing the anatomic position of the pelvic organs. Many reports use terms for the description of pelvic organ prolapse which are undefined; none of the many aspiring grading systems has been adequately validated with respect either to reproducibility or to the clinical significance of different grades. The absence of standard, validated definitions prevents comparisons of published series from different institutions and longitudinal evaluation of an individual patient. A primary goal of this report is to introduce a system that will allow the accurate, quantitative description of pelvic support findings in individual patients.

This document is a first effort toward the establishment of standard, reliable, and validated descriptions of female pelvic anatomy and function. The subcommittee acknowledges a need for well designed reliability studies to evaluate and validate various descriptions and definitions. We have tried to develop guidelines that will promote new insights rather than existing biases. Acknowledgement of these standards in written publications and scientific presentations should be indicated in the Methods Section with the following statement: 'Methods, definitions, and descriptions conform to the standards recommended by the International Continence Society, except where specifically noted'.

2 DESCRIPTION OF PELVIC ORGAN PROLAPSE

The clinical description of pelvic floor anatomy is determined during the physical examination of the external genitalia and vaginal canal. The specifics of the examination technique are not dictated by this document, however authors should precisely describe their specific technique. Segments of the lower reproductive tract will replace such terms as 'cystocele, rectocele, enterocele, or urethrovesical junction' because these terms may imply an unrealistic certainty as to the structures on the other side of the reproductive tract bulge particularly in women who have had previous prolapse surgery.

2.1 Conditions of the Examination

Many variables of examination technique may influence findings in patients with pelvic organ prolapse. It is critical that the examiner sees and describes the maximum protrusion noted by the individual subject during her daily activities. Therefore the criteria for the end point of the examination and the full development of the prolapse must be specified in any report.

Suggested criteria for demonstration of maximum prolapse should include one or all of the following:

Other variables of technique that should be specified during the quantitative description (Section 2.2) and the ordinal staging (Section 2.3) of pelvic organ prolapse include the following:

There is a critical need to define the importance of all variables of technique as they relate to the ease of assessment and reproducibility of measurements. Researchers should determine the inter-observer and intra-observer reliability of measurements made with their assessment techniques before utilizing them as baseline and outcome variables. Manuscript descriptions of assessment techniques should include sufficient detail to ensure that other researchers can precisely replicate them.

2.2 Quantitative Description of Pelvic Organ Position

This description system is a tandem profile in that it contains a series of component measurements grouped together in combination, but listed separately in tandem, without being fused into a distinctive new expression or 'grade'. It allows for the precise description of an individual woman's pelvic support without assigning a 'severity value'. Second, it allows accurate site-specific observations of the stability or progression of prolapse over time by the same or different observers. Finally, it allows similar judgements as to the outcome of surgical repair of prolapse. For example, noting that a surgical procedure moved the vaginal apex from 0.5 cm beyond the hymeneal ring to 0.5 cm above the hymeneal ring denotes more meager improvement than stating that the prolapse was reduced from Grade 3 to Grade 1 as would be the case using some current grading systems.

2.2.1. Definition of Anatomic Landmarks

Prolapse should be evaluated by a standard system relative to clearly defined anatomic points of reference. These are of two types, fixed reference points and defined points for measurement.

a. Fixed Point of Reference
Prolapse should be evaluated relative to a fixed anatomic landmark which can be consistently and precisely identified. The hymen will be the fixed point of reference used throughout this system of quantitative prolapse description.

Visually, the hymen provides a precisely identifiable landmark for reference. Although it is recognized that the plane of the hymen is somewhat variable depending upon the degree of levator ani dysfunction, it remains the best landmark available. 'Hymen' is preferable to the ill-defined and imprecise term ‘introitus'. The anatomic position of the six defined points for measurement [section 2.2.2(b)] should be centimeters above or proximal to the hymen (negative number) or centimeters below or distal to the hymen (positive number) with the plane of the hymen being defined as zero (0). For example, a cervix that protruded 3 cm distal to the hymen would be +3 cm.

Palpably, the ischial spines provide precisely identifiable landmarks. In the sitting or standing position or in situations with limited viability due to obesity or limited ability for hip abduction, the position of the cervix or the leading point of the prolapse relative to the ischial spines may be measured by palpation. Measurements so obtained should be normalized to the level of the hymen by noting the distance between the ischial spines and the plane of the hymen. For example, a cervix that is 3 cm distal to the ischial spines would be at -2cm if the spines were 5 cm above the plane of the hymen.

b. Defined Points for Measurement
Anterior Vaginal Wall. Because the only structure directly visible to the examiner is the surface of the vagina, anterior prolapse should be discussed in terms of a segment of the vaginal wall rather than the organs which lie behind it. Thus, the term 'anterior vaginal wall prolapse' is preferable to 'cystocele' or 'anterior enterocele' unless the organs involved are identified by ancillary tests.

Vaginal Apex These points represent the most proximal locations of the normally positioned lower reproductive tract.

Posterior Vaginal Wall Analogous to anterior prolapse, posterior prolapse should be discussed in terms of segments of the vaginal wall rather than the organs which lie behind it. Thus, the term 'posterior vaginal wall prolapse' is preferable to 'rectocele' or 'enterocele' unless the organs involved are identified by ancillary tests. If small bowel appears to be present in the rectovaginal space, the examiner should comment on this fact and should clearly describe the basis for this clinical impression (e.g., by observation of peristaltic activity in the distended posterior vagina, by palpation of loops of small bowel between an examining finger in the rectum and one in the vagina, etc). In such cases, a 'pulsion' addendum to the point Bp position should be noted (e.g., Bp = +5[pulsion]). See sections 3.1(a) and 3.1(b) for further discussion.

c. Other Landmarks and Measurements
The genital hiatus is measured from the middle of the external urethral meatus to the posterior midline hymen. If the location of the hymen is distorted by a loose band of skin without underlying muscle or connective tissue, the firm palpable tissue of the perineal body should be substituted as the posterior margin for this measurement.

The perineal body is measured from the middle of the external urethral meatus to the posterior midline hymen. If the location of the hymen is distorted by a loose band of skin without underlying muscle or connective tissue, the firm palpable tissue of the perineal body should be substituted as the posterior margin for this measurement.

The perineal body is measured from the posterior margin of the genital hiatus (as just described) to the mid-anal opening. Measurement of the genital hiatus and perineal body are expressed in centimeters.

The total vaginal length is the greatest depth of the vagina in cm when Point C or D is reduced to its full normal position. Note: Eccentric elongation of a prolapsed anterior or posterior vaginal wall should not be included in the measurement of total vaginal length. (See Figure 4.A. and accompanying discussion). The points and measurements discussed in this section are represented in Figure 1.

2.2.2. Making and Recording Measurements

The position of Points Aa, Ba, Ap, Bp, C, and (if applicable) D with reference to the hymen should be measured and recorded. Positions are expressed as centimeters above or proximal to the hymen (negative number) or centimeters below or distal to the hymen (positive number) with the plane of the hymen being defined as zero (0). While an examiner may be able to make measurements to the nearest half (0.5) cm, it is doubtful that further precision is possible. All reports should clearly specify how measurements were derived. For example, were direct measurements made using a probe, ruler, glove, speculum or other device marked in centimeters, were indirect measurements made with the examiner's fingers and then measured off a centimeter tape, were measurements estimated by the examiner without using a graduated device, or were combinations of techniques used? If customized measuring devices were used, diagrams of such should be included in any manuscript or presentation.

Measurements may be recorded as a simple line of numbers (e.g., -3, -3, -7, -9, -3, -3, 9, 2, 2 for Points Aa, Ba, C, D, Bp, Ap, total vaginal length, genital hiatus, and perineal body respectively). Note that the last three numbers have no sign (i.e., - or +) attached to them because they denote lengths and not positions relative to the hymen. Alternatively, a three by three 'tic-tac-toe' grid can be used to organize concisely the measurements as noted in Figure 2. If point D is not applicable due to a prior hysterectomy, this should be noted as such with 'NA' or '-' in either the line of numbers or in the grid.

table
Figure 3 is a line diagram contrasting measurements indicating normal support to those of post hysterectomy vaginal eversion.

In the example of normal support (Figure 3.A.), Points Aa and Ba and Points Ap and Bp are all -3 since there is no anterior or posterior wall descent. The lowest point of the cervix is 8 cm above the hymen (-8) and the posterior fornix is 2 cm above this (-10). The vaginal length is 10 cm and the genital hiatus and perineal body measure 2 and 3 cm respectively.

In the example of complete eversion (Figure 3.B.), the most distal point of the anterior wall (Point Ba), the vaginal cuff scar (Point C), and the most distal point of the posterior wall (Point Bp) are all at the same position (+8) and Points Aa and Ap are maximally distal (both at +3). The fact that the total vaginal length equals the maximum protrusion reflects the fact that the eversion is total.

Figure 4 is a line diagram representing predominant anterior and posterior vaginal wall prolapse with partial vault descent.

In the example of a predominant anterior support defect (Figure 4.A.), the leading point of the prolapse is the upper anterior vaginal wall, Point Ba (+6). Note that there is significant elongation of the bulging anterior wall. Point Aa is maximally distal (+3) and the vaginal cuff scar is 2 cm above the hymen (C = -2). The cuff scar has undergone 4 cm of descent since it would be at -6 (the total vaginal length) if it were perfectly supported. In this example, the total vaginal length is not the maximum depth of the vagina with the elongated anterior vaginal wall maximally reduced, but rather the depth of the vagina at the cuff with Point C reduced to its normal full extent as specified in Section 2.2.1(c).

In the example of the predominant posterior support defect (Figure 4.B.), the leading point of the prolapse is the upper posterior vaginal wall, Point Bp (+5). Point Ap is 2 cm distal to the hymen (+2) and the vaginal cuff scar is 6 cm above the hymen (-6). The cuff has undergone only 2 cm of descent since it would be at -8 (the total vaginal length) if it were perfectly supported.

2.3 Ordinal Staging of Pelvic Organ Prolapse

The tandem profile for quantifying prolapse just described provides a precise description of anatomy for individual patients. However, because of the many possible combinations, such profiles cannot be directly ranked; the many variations are too numerous to permit useful analysis and comparisons when populations are studied. Consequently they are analogous to other tandem profiles such as the TNM Index for various cancers. For the TNM description of individual patient's cancers to be useful in population studies evaluating prognosis or response to therapy, they are clustered into an ordinal set of stages. Ordinal stages represent adjacent categories than can be ranked in an ascending sequence of magnitude, but the categories are assigned arbitrarily and the intervals between them cannot be actually measured.

While the committee is aware of the arbitrary nature of an ordinal staging system and the possible biases that it introduces, we conclude such a system is necessary if populations are to be described and compared, if symptoms putatively related to prolapse are to be evaluated, and if the results of various treatment options are to be assessed and compared.

Stages are assigned according to the most severe portion of the prolapse when the full extent of the protrusion has been demonstrated according to the criteria in Section 2.1. In order for a stage to be assigned to an individual subject, it is essential that her quantitative description be completed first. The 2 cm buffer related to the total vaginal length in Stages 0 and IV is an effort to compensate for vaginal distensibility and the inherent imprecision of the measurement of total vaginal length. The 2 cm buffer around the hymen in Stage II is an effort to avoid confusing a stage to a single plane and to acknowledge practical limits of precision in this assessment.

a Stage 0
No prolapse is demonstrated. Points Aa, Ap, Ba, and Bp are all at -3 cm and either Point C or D is between -X cm and - (X-2) cm, where X = the total vaginal length in cm [i.e., the quantitation value of point C or D is ó -(X-2) cm]. Figure 3.A. represents Stage 0 pelvic organ prolapse.

b Stage I
The criteria for Stage 0 are not met but the most distal portion of the prolapse is more than 1 cm above the level of the hymen (i.e., its quantitation value is < -1 cm). Stage I can be subgrouped according to which portion of the lower reproductive tract is the most distal part of the prolapse using the following letter qualifiers: a = anterior vaginal wall, p = posterior vaginal wall, C = vaginal cuff, Cx = cervix, and Aa, Ap, Ba, Bp, and D for the Points of measurement already defined. (e.g., I-Cx if the cervix is the most distal, I-Bp if the upper posterior wall is most distal, or I- if the junction of the distal and proximal anterior wall is the most distal part of the prolapse.

c Stage II
The most distal portion of the prolapse is 1 cm or less proximal to or distal to the plane of the hymen (i.e., its quantitation value is ò -1 cm but ó + 1cm). Stage II can be subgrouped according to the scheme described under Stage I (e.g., II-a, II-C, or II-Bp).

d Stage III
The most distal portion of the prolapse is more than 1 cm below the plane of the hymen but protrudes no further than two centimeters less than the total vaginal length in cm [i.e., its quantitation value is > +1 cm but < +(X-2) cm where X = total vaginal length]. Stage III can be subgrouped according to the scheme described under Stage I. For example, Figure 4.A. represents State III-Ba and Figure 4.B. represents Stage III-Bp prolapse.

e Stage IV
Essentially complete eversion of the total length of the lower genital tract is demonstrated. The distal portion of the prolapse protrudes to at least (X-2) cm where X = the total vaginal length in cm [i.e., its quantitation value is ò + )X-2) cm]. In most instances, the leading edge of Stage IV prolapse will be the cervix or vaginal cuff scar. Rare exceptions to this can be noted according to the subgrouping scheme described under Stage I. Figure 3.B. represents Stage IV-C prolapse. Table 1 summarizes the staging system.

3 ANCILLARY TECHNIQUES FOR DESCRIBING PELVIC ORGAN PROLAPSE

This series of procedures may help to further characterize pelvic organ prolapse in an individual patient. They are considered ancillary either because they are not yet standardized or validated or because they are not universally available to all patients.

Authors utilizing these procedures should include the following information in their manuscripts.

Table 1

3.1 Supplementary Physical Examination Techniques

Many of these techniques are essential to the adequate pre-operative evaluation of a patient with pelvic organ prolapse. While they do not directly affect either the tandem profile or the ordinal stage, they are important for the selection and performance of an effective surgical repair. These techniques include, but are not necessarily limited to, the following:

3.2 Endoscopy

Cystoscopic visualization of bowel peristalsis under the bladder base or trigone may identify an anterior enterocele in some patients. The endoscopic visualization of the bladder base and rectum and observation of the voluntary constriction and dilation of the urethra, vagina, and rectum has, to date, played a minor role in the evaluation of pelvic floor anatomy and function. When such techniques are described, authors should include the type, size, and lens angle of the endoscope used, the doses of any analgesic, sedative, or anesthetic agents used, and a statement of the level of consciousness of the subjects in addition to a description of the other conditions of the examination.

3.3 Photography

Still photographic documentation of prolapse beyond Stage II may utilized both to document serial changes in individual patients and to illustrate findings for manuscripts and presentations. Photographs should contain an internal frame of reference such as a centimeter ruler or tape.

3.4 Imaging Procedures

Different imaging techniques have been used to visualize pelvic floor anatomy, support defects, and relationships among adjacent organs.

These techniques may be more accurate than physical examination in determining which organs are involved in pelvic organ prolapse. However, they share the limitations of the other techniques in this section, i.e., a lack of standardization, validation, and/or availability. For this reason, no specific technique can be recommended but guidelines for reporting various techniques will be considered.

3.4.1 General Guidelines for Imaging Procedures

Landmarks should be defined to allow comparisons with other imaging studies and the physical examination. The lower edge of the symphysis pubis should be given high priority as a landmark. Other examples of bony landmarks include the superior edge of the pubic symphysis, the ischial spine, the obturator foramen, and the promontory of the sacrum.

All reports on imaging techniques should specify the following:

3.4.2 Ultrasonography

Continuous visualization of dynamic events is possible. All reports using ultrasound should include the following information:

3.4.3 Contrast Radiography

Contrast radiography may be static or dynamic and may include voiding colpo-cysto-urethrography, defecography, peritoneography, and pelvic fluoroscopy among others. All reports of contrast radiography should include the following information:

3.4.4 Computed Tomography and Magnetic Resonance Imaging

These techniques do not allow for continuous imaging under dynamic conditions. Currently available equipment usually dictates supine scanning. Specifics of the technique should be specified including:

3.5 Surgical Assessment

Intra-operative evaluation of pelvic support defects is intuitively attractive but as yet of unproven value. The effects of anesthesia, diminished muscle tone, and loss of consciousness are of unknown magnitude and direction. Limitations due to the position of the patient must also be evaluated.

4 PELVIC FLOOR MUSCLE TESTING

Pelvic floor muscles are voluntarily controlled, but selective contraction and relaxation necessitates muscle awareness. Optimal squeezing technique involves contraction of the pelvic floor muscles and without a Valsalva maneuver. Squeezing synergists are the intraurethral and anal sphincteric muscles. In normal voiding, defecation, and optimal abdominal-strain voiding, the pelvic floor is relaxed, while the abdominal wall and the diaphragm may contract. With coughs and sneezes and often when other stresses are applied, the pelvic floor and abdominal wall are contracted simultaneously.

Evaluation and measurement of pelvic floor muscle function includes 1) an assessment of the patient's ability to contract and relax the pelvic muscles selectively (i.e., squeezing without abdominal straining and vice versa) and 2) measurement of the force (strength) of contraction.

There are pitfalls in the measurement of pelvic floor muscle function because the muscles are invisible to the investigator and because patients often simultaneously and erroneously activate other muscles. Contraction of the abdominal, gluteal, and hip adductor muscles, Valsalva maneuver, straining, breath holding, and forced inspirations are typically seen. These factors affect the reliability of available testing modalities and have to be taken into consideration in the interpretation of these tests.

The individual types of tests cited in this report are based both on the scientific literature and current clinical practice. It is the intent of the committee neither to endorse specific tests or techniques nor to restrict evaluations to the examples given. The standards recommended are intended to facilitate comparison of results obtained by different investigators and to allow investigators to replicate studies precisely.

For all types of measuring techniques the following should be specified:

4.1 Inspection

A visual assessment of muscle integrity, including a description of scarring and symmetry, should be performed. Pelvic floor contraction causes inward movement of the perineum and straining causes the opposite movement. Perineal movements can be observed directly or assessed indirectly by movement of an externally visible device placed into the vagina or urethra. The abdominal wall and other specified regions might be watched simultaneously. The type, size and placement of any device used should be specified as should the state of undress of the patient.

4.2 Palpation

Palpation may include digital examination of the pelvic floor muscles through the vagina or rectum as well as assessment of the perineum, abdominal wall, and/or other specified regions. The number of fingers and their position should be specified. Scales for the description of the strength of voluntary and reflex (e.g., with coughing) contractions and of the degree of voluntary relaxation should be clearly described and intra- and inter-observer reliability documented. Standardized palpation techniques could also be developed for the semiquantitative estimation of the bulk or thickness of pelvic floor musculature around the circumference of the genital hiatus. These techniques could allow for the localization of any atrophic or asymmetric segments.

4.3 Electromyography

Electromyography from the pelvic floor muscles can be recorded alone or in combination with other measurements. Needle electrodes permit visualization of individual motor unit action potentials, while surface or wire electrodes detect action potentials from groups of adjacent motor units underlying or surrounding the electrodes. Interpretation of signals from these latter electrodes must take into consideration that signals from erroneously contracted adjacent muscles may interfere with signals from the muscles of interest. Reports of electromyographic recordings should specify the following:

4.4 Pressure Recording

Measurements of urethral, vaginal, and anal pressures may be used to assess pelvic floor muscle control and strength. However, interpretations based on these pressure measurements must be made with a knowledge of their potential for artifact and their unproven or limited reproducibility. Anal sphincter contractions, rectal peristalsis, detrusor contractions, and abdominal straining can affect pressure measurements. Pressures recorded from the proximal vagina accurately mimic fluctuations in abdominal pressure. Therefore it may be important to compare vaginal pressures to simultaneously measured vesical or rectal pressures. Reports using pressure measurements should specify the following:

As noted in section 4.1, observation of the perineum is an easy and reliable way to assess for abnormal straining during an attempt at a pelvic muscle contraction. Significant straining or a Valsalva maneuver causes downward/caudal movement of the perineum; a correctly performed pelvic muscle contraction caused inward/cephalad movement of the perineum. Observation for perineal movement should be considered as an additional validation procedure whenever pressure measurements are recorded.

5 DESCRIPTION OF FUNCTIONAL SYMPTOMS

Functional deficits caused by pelvic organ prolapse and pelvic floor dysfunction are not well characterized or absolutely established. There is an ongoing need to develop, standardize, and validate various clinimetric scales such as condition-specific quality of life questionnaires for each of the four functional symptom groups (section 5.1 through 5.4) thought to be related to pelvic organ prolapse.

Researchers in this area should try to use standardized and validated symptom scales whenever possible. They must ask precisely the same questions regarding functional symptoms before and after therapeutic intervention. The description of functional symptoms should be directed toward four primary areas: 1) lower urinary tract, 2) bowel, 3) sexual, and 4) other local symptoms.

5.1 Urinary Symptoms

This report does not supplant any currently approved ICS terminology related to lower urinary tract function [1]. However, some important prolapse related symptoms are not included in the current standards (e.g., the need to manually reduce the prolapse or assume an unusual position to initiate or complete micturition). Urinary symptoms that should be considered for dichotomous, ordinal, or visual analog scaling include, but are not limited to, the following:

5.2 Bowel Symptoms

Bowel symptoms that should be considered for dichotomous, ordinal, or visual analog scaling include, but are not limited to, the following:

5.3. Sexual Symptoms

Research is needed to attempt to differentiate the complex and multifactorial aspects of 'satisfactory sexual function' as it relates to pelvic organ prolapse and pelvic floor dysfunction. It may be difficult to distinguish between the ability to have vaginal intercourse and normal sexual function. The development of satisfactory tools will require multidisciplinary collaboration. Sexual function symptoms that should be considered for dichotomous, ordinal, or visual analog scaling include, but are not limited to, the following:

5.4 Other Local Symptoms

We currently lack knowledge regarding the precise nature of symptoms that may be caused by the presence of a protrusion or bulge. Possible anatomically based symptoms that should be considered for dichotomous, ordinal, or visual analog scaling include, but are not limited to, the following:

Reference

1Abrams P, Blaivas JG, Stanton SL, Andersen JT: The International Continence Society Committee on Standardization of Terminology. The standardization of terminology of lower urinary tract function. Scand J Urol Nephrol 1988; 114S:5-19

Acknowledgements

The subcommittee would like to acknowledge the contributions of the following consultants who contributed to the development and revision of this document:

W. Glenn Hurt, M.D., Richmond, VA, U.S.
Bernhard Schussler, M.D., Luzern, Switzerland
L. Lewis Wall, M.D.D.Phil., New Orleans, LA, U.S.