Contribution of posture to anorectal manometric measurements: are the measurements in left-lateral position physiologic?
OBJECTIVE
Anorectal manometry is commonly used to investigate fecal incontinence. Traditional practice dictates that measurements are performed with the patient in the left-lateral position however, episodes of fecal incontinence usually occur in the erect position. The influence of erect posture on anorectal manometry has not been studied.


METHODS
We examined the contribution of posture to commonly measured variables during manometry by performing assessment in the left-lateral position and the erect posture. Maximum mean resting pressure, vector volumes, and resting pressure gradient were compared.


RESULTS
Complete data were available for 172 patients. Median age was 55 (interquartile range, 44-65) years. Thirty-seven (22 percent) patients were continent, and 135 (78 percent) were incontinent. Both resting pressure and vector volume increased significantly in the erect position for both continent (P = 0.008 and 0.001, respectively) and incontinent (P = 0.001 for both) patients. A significant negative correlation was seen between severity of incontinence and resting pressure in the erect posture and amount of change in maximum mean resting pressure from left-lateral to erect posture (Spearman coefficients = -0.203, -0.211, and P = 0.013, 0.017, respectively) but not with maximum mean resting pressure in the left-lateral position (Spearman coefficient = -0.119; P = 0.164).


CONCLUSIONS
Our study shows significant increase in measurements of manometric variables in the erect position. The increase may be related to anal cushions, which have a significant role in this position. The measurements in erect posture are better correlated with severity of incontinence and may be a more physiologic method of performing anorectal manometry.
Thekkinkattil
Dinesh K
DK
Department of Colorectal Surgery, The General Infirmary at Leeds, Leeds, West Yorkshire, United Kingdom.
Lim
Michael K
MK
Nicholls
Marcus J
MJ
Sagar
Peter M
PM
Finan
Paul J
PJ
Burke
Dermot A
DA
D000328:Adult; D000368:Aged; D005242:Fecal Incontinence / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011312:Pressure; D011379:Prognosis; D012007:Rectum / Q000503:physiopathology*; D012146:Rest / Q000502:physiology; D012720:Severity of Illness Index