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this first issue the following interesting article had been
chosen for discussion from the flow equation point of View
Augmentation and Stimulated Gracilis Anal Neosphincter. A
New Approach in the Management of fecal Urgency and incontinence.
N. S. Williams, O. A. Ogunbiyi, S. M. Scott, O. Fajobi,P.
J. Lunniss. Diseases of The Colon & Rectum. February 2001,44(2).
192 - 8. From London, UK. http://www.discolrect.com/
the fact that this is a preliminary report on only 3 cases yet
it acquired its importance from its authors and the novality
of this comprehensive approach to the problem of anal incontinence
including its 2 major components namely the rectum and anal
According to the flow equation:
Flow (incontinence) = Intrarectal Pressure / Anal canal resistance
In the above mentioned study the authors had used the intrarectal
pressure as a study end-point for success of rectal augmentation
as well as clinical urgency A. I. As a clinical end-point.
From the flow equation point of flow this is quite justified
since incontinence (flow) is dependent on 4 primary factors
1. Intrarectal pressure (IRP).
2. Anal canal length (ACL).
3. Anal canal diameter (ACD).
4. Dynamic Viscosity of the stools (DV).
The IRP represents the final common pathway of rectal factors
maintaining normal continence including rectal capacity, rectal
sensitivity and rectal compliance. Being also affected by intestinal
factors such as the rate of rectal filling being higher in hurried
3 studied patients had high amplitude rectal contractions on
ambulatory anorectal manometry. 2 of them were coincident with
clinical urgency incontinence on ambulatory monitoring.
the three patients experienced clinical abolition of their urgency
incontinence postoperatively in addition high amplitude rectal
waves and other parameters of rectal motility were also improved
in the 3 studied patients. This confirms the relation between
clinically significant A.I. and intrarectal pressure as final
primary rectal factor in A.I. as is suggested in the flow equation.
patient who had simultaneous rectal augmentation and Dynamic
Graciloplasty had developed obstructed defecation. This in the
flow equation point of view could be prevented or at least anticipated
by staging the procedure and calculation of A. canal resistance
during defecation after the dynamic Graciloplasty which can
detect any possible iatrogenic anismus in the neosphincter thus
avoiding the addition of the rectal augmentation if possible
or at least anticipating the obstructed defecation if it seemed
to be necessary for abolishion of urgency A.I.