We thus studied the results of anal vector manometry performed in 44 patients (42 women and 2 men, mean age: 64 years-old, range: 23 to 79) complaining of anal incontinence, in whom the diagnostic work-up included an anal ultrasonography (EAU) (performed through the endo-anal and endo-vaginal route) and a dynamic pelvic viscerogram (PV) (barium opacification of pelvic organs), allowing the identification of patients with anal sphincter defects and / or rectal prolapse. Indeed, both situations may be missed despite a thorough clinical investigation: anal sphincter defects disclosed only by EAU are a frequent occurrence, and intra-anal rectal prolapse (or recto-anal intussuception) may be under-diagnosed by clinical examination only.
Anal incontinence was considered when patients experienced significant accidental bowel leakages of liquid or solid stools, recurrent episodes of anal soiling, or urgent stools with a retention time of less than fifteen minutes. The severity of anal incontinence symptoms was assessed using the clinical score proposed by Jorge et al . Associated symptoms such as stress urinary incontinence and severe dyschesia (defined as the need of digital anal manoeuvres to obtain defecation) were also inquired after. Past surgical and obstetrical histories were obtained in all patients.
EAU was performed using a rigid 360° rotating probe with a transducer frequency of 7 or 10 MHz (Brüel & Kjaer, Naerum, Denmark): internal and external anal sphincter defects were identified as previously described [6, 7], and the radial size of the defects measured.
Anal vector manometry was performed using a radial 8-lumen perfused catheter (Zynectics Medical, Inc, Salt Lake City, UT), an automated catheter-puller at 10 mm/s (Uro Synectics, Medtronic, Rueil-Malmaison, France): three pull-outs were performed through the anal canal at rest and during voluntary squeeze. The mean values for anal pressures and the anal asymmetry indexes, at rest and during voluntary squeeze, were calculated using a commercially available software (Polygram 98, Medtronic, Rueil-Malmaison, France). The anal asymmetry index is calculated by adding the 8 pressures obtained at the high pressure zone (defined as the anal region with mean pressures above 80% of the maximal mean pressure), dividing this by the maximum pressure multiplied by the number of channels and subtracting this value from 1. Values are reported as percentage values, with a perfect symmetry having a value of zero.
Pelvic viscerogram allowed for the identification of intra-anal or the confirmation of exteriorised rectal prolapse. PV consists of a dynamic X-Ray examination of the position and movements of pelvic organs at rest, during straining and squeezing with patients sitting on a chair. Filling of the rectum is obtained with a home-made barium paste (barium sulfate cooked with corn starch and water; vaginal marking is done by injection of a 20 ml syringe containing 10 ml of liquid barium sulfate (to mark the vaginal walls) and 10 ml of the barium paste to mould the vaginal cavity. Finally, the bladder is filled with 200 ml of water-soluble contrast medium (Telebrix) through a small catheter left in place during the examination. Intra-anal rectal prolapse was defined as the invagination of part of the rectal mucosa within the anal canal. A rectal invagination above the upper limit of the anal canal was not considered for the diagnosis of rectal prolapse.
Statistical analyses between groups were performed by one-way ANOVA or Chi2-test as appropriate. Results are expressed as mean (SEM), unless otherwise indicated. Statistical significance was set to be 0.05.