Until recently, assessment of levator function, if undertaken at all, was limited to grading muscle strength and endurance, using the modified Oxford Grading system first suggested by Laycock (Laycock, 1988). Physiotherapists have a long history of using palpation to assess skeletal muscle and some, with appropriate postgraduate training, have extended their skills to include digital assessment of pelvic floor muscle by the vaginal or transanal route. Within the physiotherapy literature there are many reports of palpation to assess pelvic floor muscle contraction, and some describing the identification of pain and trigger points, and evaluation of muscle tone.
However, although clinical anecdote suggests some physiotherapists recognize other characteristics suggesting muscle dysfunction (e.g. holes, gaps, ridges, scarring) or pelvic floor dysfunction (e.g. width between medial edges of pelvic floor muscle) with palpation it is difficult to find any literature describing the techniques needed to do this or their accuracy or repeatability. Mantle (Mantle 2004) noted that with training and experience a physiotherapist might be able to discern muscle integrity, scarring, and the width between the medial borders of the pelvic floor muscles, with palpation. It is not clear to what extent physiotherapists are able to do this reliably or how such characteristics are to be recorded.
In 1943, an obstetrician from Kansas City published the findings of a palpatory assessment of 1000 women delivered by him personally (Gainey, 1943). Gainey described trauma to what he called the ‘pubococcygeus’ muscle, and from his description it is quite clear that he did detect avulsion injuries. In fact, the prevalence of such defects quoted by him (about 20% in primiparous women) agrees very well with modern work using MR (DeLancey et al., 2003) and Pelvic Floor Ultrasound (Dietz and Steensma, 2006). Evidently, if it was possible to palpate such trauma in 1943, it should be possible today.
Videos 1 and 2 demonstrate the spatial relationships of inferior pubic rami and levator ani muscle. The muscle defines a potential hernial portal, and there are enormous differences between one patient and the next. It is nothing short of amazing that this important structure, so easily accessible to palpation, has so far been largely ignored by those physicians dealing with pelvic floor disorders. Figure 1 and 2 explain how palpatory assessment of the inferior part of the levator, the puborectalis muscle, should be undertaken.
Currently the assessment of levator function by physiotherapists, nurse continence advisors, gynaecologists and urologists is (at best) limited to grading systems focusing on “squeeze and lift” and in need of improvement. We propose a visual recording system for findings obtained on palpation of the pubovisceral muscle (see Fig. 3). Such a system should include both some form of Oxford grading for “squeeze and lift” bilaterally, as well as grading for resting tone (conveniently graded 0-5 to accord with the Oxford system, see Table 1 for a suggested scale).
In addition, one should attempt a morphological assessment of the pubovisceral muscle, and document findings either as defects or gaps (outlined and shaded area on the muscle diagram) or thinning (outlined and hatched obliquely). This proposed system could form the basis of teaching efforts to improve on our palpatory assessment skills and would allow easier communication amongst clinical practitioners and researchers.
Clearly, assessment of the pubovisceral muscle by palpation is an advanced skill that requires significant teaching, most conveniently in a unit that allows for instant comparison with findings on imaging. Without additional training, agreement between a clinical assessor and imaging is likely to be poor (Dietz et al., 2006, Kearney et al., 2006, Shek et al., 2007). However, there is no doubt that palpatory assessment of the pubovisceral muscle is within reach of any practitioner in the field. After proper training, agreement between assessors is sufficient for clinical use at least (Dietz and Shek, 2008). Levator trauma results in a marked reduction of contraction strength as defined by Oxford Grading (Dietz and Shek, 2008), and a difference of one Oxford grade or more is associated with levator trauma on the weaker side. This implies that palpation for contraction strength can help alert the examiner to the potential presence of an avulsion which should be actively sought in anyone with poor contractility. Many women with absent voluntary PFM activity show evidence of trauma rather than nerve damage (Sarma et al., 2009).
We have designed a pelvic floor model for palpation training (figure 4), and this model will be available free of charge to everyone participating in one of our courses from mid- 2012 onwards.
There is another aspect of levator assessment that can yield important information on clinical examination. It has recently become clear that the size of the levator hiatus can be estimated by determining the sum of the genital hiatus (gh) and perineal body (pb) in the context of the ICS POP-Q examination. Gh + pb, ie., the distance between the external urethral meatus and the centre of the anus, when measured on maximal Valsalva with a simple ruler, is highly predictive of symptoms and signs of prolapse, and it is very strongly correlated with hiatal area on Valsalva (Khunda et al., 2011). We have defined abnormal hiatal distensibility as 7 cm or more (see Figure 5 and Table 2).
This recent discovery means that it is possible to determine the two main predictors of recurrence risk after prolapse surgery on clinical examination, within very few minutes, at virtually no cost (see Levator Trauma).
Figure 4: Model for the training of the detection of levator trauma by palpation
Video 1: This is what the pelvic floor muscle looks like normally, seen from below.
Video 2: Findings on dissection of a normal m. puborectalis.
Figure 1: Palpation of levator trauma. On the left, the palpating finger finds continuous soft tissue resistance between the main body of the pubovisceral muscle and the pelvic sidewall. On the right the bone of the inferior pubic ramus is denuded, with a gap felt between the sidewall and the main body of the pubovisceral muscle dorsally.
Figure 2: A helpful trick on palpating for integrity of the pubovisceral muscle insertion is to check the gap (arrows) between the urethra centrally and the pubovisceral muscle laterally. On levator contraction this gap should be little wider than your index finger (arrow on left), otherwise an avulsion injury is very likely (arrow on right).
Figure 3: Proposal of a documentation scheme for evaluating levator function and anatomy.
Table 1: Proposed scale for grading of pelvic floor muscle resting tone
Table 2: Clinical determination of hiatal balloon- ing by measuring gh+pb (n= 419).
Figure 5: Clinical and ultrasonic determination of hiatal ballooning on Valsalva.