Anorectal Manometry: Conventional vs. HRAM
Quinlivan L1, Barry L1, Yousif K2, McCarthy J 2& Buckley M1&2
1GI Function Lab, Mercy University Hospital, Cork 2Dept. Gastroenterology, Mercy University Hospital, Cork
Defecatory Disorders are a common problem in the community; ano-rectal manometry allows profiling of the strength of the internal and external anl sphincters as well as allowing the identification of defecatory disorders. High resolution ano-rectal manometry (HRAM) catheters were introduced in 2007 and have increasing come to be used in routine clinical practice.
We aim to investigate the advantages of HRAM over conventional manometry (CM) particularly multiple circumferential sensors with limited spaces between them, with the use of oesophageal pressure topography HRAM allows for a greater appreciation of the dynamic processes of defecation.
We compared 23 (95.6% F) patients with symptoms of faecal incontinence (FI) who attended our laboratory between May and October 2015 for conventional water perfused ano-rectal manometry with 23 (74% F) patients also with FI symptoms who underwent HRAM in our laboratory between October 2015 and January 2016
Mean ano-rectal resting pressure in those undergoing CM was 43.9mmHg +/- 19.4mmHg vs. 75.7mmHg+/- 27.47mmHg in those who underwent HRAM. 65.2% of CM patients were reported as having a hypotensive resting pressure. 17% of HRAM patients were reported with hypotensive resting pressure. CM mean squeeze pressure was 106mmHg+/- 42.41mmHg vs. 131.84mmHg+/-46.6mmHg of those who had HRAM. 34.7% of CM patients were reported with hypotensive squeeze pressure, while hypotensive Squeeze was reported in 48% of those who has HRAM.
Conventional Manometry appears to overestimate resting anal sphincter pressures when compared to HRAM. This may be due to greater distance between sensors which leads to a higher false positive rate. Defecation is a dynamic process where the mode of assessment needs to be considered carefully.