When dealing with functional disorders an exact history is important. Every patient should be asked about food and dietary intake as well as bowel function, stool frequency and consistency. Constipated patients may complain about nausea and bloating as signs for whole large bowel disorder. Pressure in the pelvis and/or inability to evacuate can be a hint for pelvic outlet obstruction. Incontinent patients should be asked about the grade of incontinence, wearing pads and social impairment. Incontinent and constipated patients may benefit from scoring systems ₄,₅,₆. It is worth mentioning that 43% of patients with constipation had a previous hysterectomy ₇.

Basic clinical examination consists of inspection, palpation and proctoscopy. Many proctological diseases can be diagnosed by inspection alone such as fistulas, fissures and external hemorrhoids. In incontinent women the short distance between the anus and the vagina can be the first sign for a suspected sphincter defect. Before we start our rectal-digital examination , we ask the patient to squeeze and push to diagnose a perineal descent or a rectal prolapse . During rectal-digital examination the whole circumference of the anal canal must be palpated. Induration as a sign for inflammation , a pouching rectocele, painful areas (e.g. anal fissures) or a malignant tumor can be felt. It is wise to assess the functional status of the sphincters during the rectal-digital examination by asking the patient to squeeze and push. Especially anterior sphincters defects or paradoxical contraction of the puborectalis muscle can thus be easily diagnosed.

To discuss the necessity of physiologic tests, we have to define our expectations for any clinical test. The following criteria are set:

1. The test should be feasible and widely available.

2. The test should be easy to tolerate for the patient.

3. The test should be helpful in the diagnosis and/or management of the relevant disorder.

4. In healthy patients a normal range should be available.

5. Measurements outside the normal range should correlate with the disease.

Opponents of physiology testing will argue that none of this mentioned criteria would be fulfilled by physiologic tests. But let us look closer to the arguments against physiology testing:

a) AVAILABILITY: It is estimated that about 0,5% - 1% of the whole population is suffering from fecal incontinence ₈. Constipation disorders are probably more common and should reach up to 10% of the normal population ₉ . Thus clinicians around the world are called upon to assess and to treat patients with such disorders. Probably many patients will be treated successfully without the use of a physiology laboratory.

b) RELIABILITY: Current anorectal physiology measurement techniques involve the insertion of probes, transducers, needles, tubes or liquids into the rectum or anal canal ₁₀,₁₁,₁₂. Any such foreign material will alter normal physiology. Furthermore we know that any measurement can only give the current status of the anorectum, but in clinical praxis more often long-term function is of interest.

c) NORMAL VALUES: AM is a useful test, but it is accepted that every lab has its own normal range. This is due to different diameters of catheters and techniques (water-perfused, pull through technique etc.). Thus data from different clinics are not comparable ₁₃. Concerning DEFA measurements of the anorectal angle are not reliable ₁₄.

d) DIAGNOSIS: Colorectal surgeons have always used their well educated index finger to assess abnormalities of the anorectal region. There are several reports in the literature that AM is not better than digital examination ₁₅. Furthermore, anterior sphincter defects can also be palpated as an immobile segment of the external sphincter during voluntary contraction during digital examination.

e) CLINICAL CORRELATES : There is no evidence that anorectal measurements predict the response to surgical intervention in borderline cases. In clinical obvious cases, measurements can only confirm the estimation done with digital examination and exact history.

Argument for physiology testing are as follows.

a) COMPLEXITY: Anorectal physiology measurements are of value in the diagnosis of disorders of the pelvic floor. These disorders can be similar, but present different physiological abnormalities and demand different treatment options. If physiologic work up is done, it should be said that it is important that no test alone is pathognomic and therefore the most important tests should be done and interpreted collectively.

b) FORENSIC IMPLICATION: A well-educated index finger may be of use in the diagnosis but will not help very much in a trial. Therefore manometry data are useful in the evaluation of incontinence , before a coloanal anastomosis is being performed or before potentially jeopardizing anorectal operations are done.

c) CONSTIPATION: Several diseases can only be diagnosed and treated with physiology means.

• Paradoxical puborectalis contraction, suspected on clinical examination, can best be diagnosed by DEFA and EMG with a painless sponge electrode 16.

• Hirschsprung´s disease: Usually this disease is diagnosed during childhood. However, sometimes patients with ultrashort Hirschsprung´s disease can be seen. Looking for the rectoanal inhibitory reflex is very easy and if positive excludes an aganglionic segment. Thus a full thickness rectal biopsy as first line diagnostic tool can be avoided.

• Perineal descent : This entity can occur due to aging, perineal trauma or repeated straining at stool. Plugging of the anal canal by rectal mucosa due to an intussusception can lead to a vicious cycle demanding more straining resulting in full thickness rectal prolapse. Physiologic tests can lead you in the direction of appropriate treatment.

• Colonic inertia : chronic idiopathic constipation is a rare, but severe disease mostly in young women. Colonic transit studies can help making the decision for a big operation. AM and DEFA can help to diagnose a mixed pattern of colonic inertia and pelvic outlet obstruction, which should firstly be treated conservatively 17.

d) FECAL INCONTINENCE: Patients with incontinent problems can profit from physiology evaluation. Especially the differentiation between isolated or multiple defects in the anal sphincter is of enormous importance. Furthermore , when a defect is present, training programs might not be successful. On the other hand, patients with neurogenic incontinence may be offered a more sophisticated operation like SNS (sacral nerve stimulation), artificial bowel sphincter or stimulated graciloplasty.

There are several physiologic tests nowadays available (Table2). The most common ones are listed below.

Figure 2

Table 2 : Physiologic tests

Anal manometry (AM)

Defecography (DEFA)

Anal endosonography (EAUS)

EMG of the pelvic floor with concentric needles or a single fiber EMG should nowadays only be done in selected patients, as this test is painful. In constipated patients use of a sponge electrode can give proper results ₁₆ . PNTML should be done, as this test may have influence on prognosis after surgical corrections of sphincter defects ₂₂,₂₃.

Transit studies can be done in various ways. The most easy and reliable way to distinguish between a colonic disorder or a pelvic outlet obstruction is done with radiopaque markers.

After ingestion from 24 markers on day 5 and 7 a plain abdominal x-ray is done to distinguish between colonic inertia and pelvic outlet obstruction ₉.

In selected cases other tests like MRI, fecal flowmetry, scintigrafic evacuation procedures as well as electrosensibility studies may be useful ₂₄, ₂₅, ₂₆.