Evaluation of a Modified London Protocol to Diagnose Defecation Disorders With High-Definition Anorectal Manometry

Anorectal manometry (ARM) is useful to diagnose defecation disorders. The International Anorectal Physiology Working Group (IAPWG) introduced a standardized sequence of maneuvers into clinical practice to perform ARM (London Protocol). Regarding the "push" maneuver, excellent consensus among IAPWG experts was limited to the number of pushes and the interval between them. The aim of this study was to assess the diagnostic accuracy of simplified ARM protocols featuring various combinations of different push durations (15, 10 or 5 s) and numbers of push attempts (two or three).

High-Definition ARM (HD-ARM) tracings from 142 patients (113 females, mean aged 54.7 ± 16.9) who underwent ARM for fecal incontinence (n = 37) or constipation (n = 105) were retrospectively reviewed. HD-ARM tracings were re-evaluated based on the following modifications to the London protocol: considering only the first two pushes; considering the first ten seconds of each push; considering the first ten seconds of the first two pushes; considering the first five seconds of each push; considering the first five seconds of the first two pushes. HD-ARM reports were redrawn because of these protocol modifications and were compared with the reports obtained using the IAPGW standard protocol in terms of manometric pattern and diagnosis.

The proposed modified protocols featuring ten- or fifteen-second pushes showed an almost perfect concordance compared with the standard of practice (k = 0.97), while the modified protocols featuring 5 s pushes showed only a fair/moderate diagnostic concordance. The latter was mainly linked to a transient increase in anal pressure (lasting on average four to five seconds).

Based on our results, two push efforts of ten seconds each may be enough to reach an accurate manometric diagnosis of defecation disorders. Five-second push may not be sufficient given the transient increase in anal pressure at the beginning of the push attempt. Performing only two push maneuvers of ten seconds each may reduce by 55 s the length of this cumbersome examination.