932 sphincter defects [12, 13]. Moreover, the reproducibility for sphincter defects and anal sphincter thickness is excellent [14]. Furthermore, the presence of atrophy of the sphincters can be established [15, 16]. Anorectal manometry is used to measure the anal pres- sures objectively and to determine the RC. Anal manometry can demonstrate lower sphincter pressures in patients with anal sphincter defects, but also in patients with atrophy and is not discriminatory [15, 16]. Anal manometry cannot predict the efficacy of physiotherapy and biofeedback [17]. Considering these diagnostic and therapeutic options, the key question is which tests influence clinical decision making. Fibres are a first line, easy to implement, inexpensive treat- ment and the effect becomes clear after several weeks. Physiotherapy or biofeedback involves more effort from both patient and physiotherapist and is more costly. Anorectal function testing cannot predict the success of physiotherapy or biofeedback [17]. In patients who are eligible for surgery, demonstration of a large sphincter defect is important. Contra- indications for sphincter repair are other (concomitant) causes such as diarrhea, severe atrophy of the sphincters, dyssynergic pelvic floor and a very small rectal compliance. Moreover, for other surgical options like SNS, gracilis plasty and artificial bowel sphincter creation, diarrhea, dyssynergic pelvic floor and a small rectal compliance are contraindications. Although it is well known that anorectal manometry cannot identify anal sphincter defects, it is still routinely performed and many investigators believe it is important or equally important as anal endosonography and contributes greatly to its test results. The aims of this study were to evaluate whether the addition of anorectal manometry to anal endosonography provided additional information to guide the surgical management of patients with FI who have failed conservative treatment and to establish clear recom- mendations for the targeted use of these tests. Materials and methods Study population All consecutive patients referred for the evaluation of FI to our function laboratory between 2003 and 2009 were included. They were prospectively assessed by a compre- hensive questionnaire regarding their perianal complaints, including the duration of symptoms, frequency of bowel movements, stool consistency and the use of pads. Other lines of enquiry included the presence of urinary inconti- nence, the use of medications and the social impact of FI on their lifestyle. Furthermore, a comprehensive past obstetric, surgical, and drug history was taken. The severity of incontinence was graded using the Vaizey and Wexner scores [18, 19]. Int J Colorectal Dis (2012) 27:931–937 Patients with inflammatory bowel disease, proctitis, pouches or rectal and prostate carcinomas were excluded. Since diarrhea by itself can cause FI, patients with chronic diarrhea were also excluded. Diarrhea was con- sidered as a stool frequency of more than three times a day and the loss of liquid stools. For the consistency of the stool, a nominal scale (liquid, soft, solid and variable) was used. We classified the patients into three groups: (1) those without anal sphincter defects; (2) those with small sphincter defects; and (3) those with large sphincter defects. A defect comprised at least 30 degrees of the circumference of the sphincter. A sphincter defect was considered small if the circumference was less than 25% and large if it was more than 25%. Anorectal manometry A four-microtip transducer, water-perfused catheter (Mui Scientific Type SR4B-5-0-0-0, Mississauga, Ontario, Can- ada) was used. The water-perfusion method was performed by means of a pull-through technique. With the patient lying in the left lateral position, the catheter was introduced into the rectum. After introduction into the rectum, the catheter was withdrawn with the automatic puller at a speed of 1 mm/s. The maximum basal pressure (MBP) was measured as the mean of highest pressure in rest (normal 40–80 mmHg). The sphincter length (SL) was equivalent to the length over which the MBP was measured. The maximum squeeze pressure (MSP) was measured as the mean increase of pressure from basal pressure during squeezing (normal ≥40 mmHg). The patient was then asked to strain on three separate occasions. No relaxation on straining was defined as a lack of pressure fall in the anal canal on straining under three consecutive attempts. Paradoxical contraction was defined as an increase of anal basal pressure upon straining. The rectoanal inhibitory reflex (RAIR) was elicited by inflating the rectal balloon to a position where the MBP was at its highest. The volume necessary for the inhibition and recovery of the MBP was recorded. The rectal compliance was determined with the rectal balloon. Air was inflated manually sing a syringe at a speed of 60 ml in 15 s. The volume of air needed to be inserted to illicit the first sensation of rectal distension, the urge to defecate and the onset of intolerable distension, which is similar to RC, was measured. Anal endosonography Anal endosonography was performed using a three- dimensional diagnostic ultrasound system (Hawk type 2050; B-K Medical, Naerum, Denmark) with a rotating