Rectal akinesia as a new cause of impaired defecation

The aim of this prospective study was to point out a new concept of dyschezia using dynamic videoproctography.

A total of 154 consecutive patients with impaired defecation prospectively underwent dynamic videoproctography from 1996 to 1998. Evacuation of thick barium of standardized consistency was fully videotaped under fluoroscopy in the sitting position. We measured the weight of barium injected into the rectum (Q1 in g), the weight of barium evacuated (Q2 in g) and the time for rectal evacuation (t in seconds). Flow rate and postdefecation residue were given by calculating Q2/t and (Q1 - Q2) X 100/Q1, respectively. We studied all patients whose flow rate and postdefecation residue were less than 5 g/second and more than 30 percent, respectively. These values were arbitrarily chosen, based on rectal evacuation in 25 controls (5 healthy volunteers together with 20 patients without dyschesia).

Nine of 154 patients with dyschesia fulfilled the criteria and had none of the usually known causes of dyschezia, such as anismus, megarectum, intussusception, rectal prolapse, rectocele, or enterocele. These nine patients had a normal rectal anatomic appearance and a wide-open short anus but despite exhausting straining efforts were unable to obtain total rectal emptying. Dynamic videoproctography brings strong arguments for an absence of rectal wall contraction, despite normal functioning pelvic floor.

Dynamic videoproctography allows identification of new features in patients with dyschesia: very slow defecation flow rate and high postdefecation residue. This new concept could be called rectal akinesia by analogy with bladder akinesia in some dysuric patients.