LAUSR

High-resolution anorectal manometry (HRAM) is a technique wherein intraluminal pressure activity is measured using a series of closely spaced pressure sensors. HRAM was designed to provide fresh insights into anorectal function and offer a new perspective on the pathophysiologic mechanisms of disordered defecation. It is a more intuitive and relatively simpler investigation to perform than the conventional low resolution anorectal manometry (ARM) with its few, largely spaced intraluminal pressure sensors. Moreover, it facilitates a more precise correlation between anatomy and function, providing a detailed topographic and colorimetric mapping of the anorectal function without the need for pull-through maneuvers to properly position the manometry catheter [1]. Given its technological superiority, the question remains regarding the diagnostic benefits of this advanced technology, in particular with regard to the diagnosis and management of disordered defecation, since its clinical value remains uncertain despite it becoming the gold standard for esophageal motility testing [2]. Indeed, many gastroenterologists and surgeons are convinced that further studies are necessary prior to recommending HRAM in preference to ARM when managing continence and defecation disorders [1, 3]. These considerations notwithstanding, we believe that the valuable efforts of the International Anorectal Physiology Working Group (IAPWG) on developing the London classification was truly noteworthy since it established consensus and minimum standards for performing HRAM according to a standardized protocol applicable to devices produced by any manufacturer. Furthermore, on the basis of a consensus agreement between internationally recognized experts, the London classification provided a standardized benchmark for performing manometry testing and a system for homogenous classification and diagnostic approach of disordered defecation [4]. The protocol was necessary since both HRAM and ARM suffered from discrepant methods for data acquisition and lack of agreement on analysis, metrics, and interpretation [5], factors that reduced data generalizability which in turn impaired the comparison of data between centers and affected pooling of data for multicenter collaborative studies. Keeping in mind that the London classification is a major step forward, the timing, number, and order of constituent HRAM maneuvers have been proposed on the basis of expert opinion, namely the IAPWG members. Moreover, the authors themselves acknowledged that additional refinement based on the everyday practice of the many motility laboratories involved is needed in order to increase generalizability and relevance [4]. The paper by Ang et al. [6] published in the current issue of Digestive Disease and Sciences is a welcome effort to validate and improve the London protocol generated by a busy motility laboratory. The authors aimed to assess the diagnostic yield of HRAM in determining disorders of anal sphincter tone and contractility by comparing the physiologic measures obtained according to the IAPWG protocol with a modified (simplified) protocol. The trial protocol involved a shorter rest period at baseline, fewer short squeezes, and a shorter recovery interval after each short squeeze. On the basis of a careful, retrospective analysis, the authors concluded that a reduced resting period length from 60 to 30 s to test for anal tone, the inclusion of only 2 rather * Giuseppe Chiarioni [email protected]