OBSTRUCTIVE DEFECATION - A FAILURE OF RECTOANAL COORDINATION

Objective: The pathophysiology of obstructive defecation is unclear. W e investigated whether impaired rectoanal coordination causes obstruct ive defecation and if this dysfunction can be corrected by biofeedback therapy. Methods: We prospectively studied 25 healthy subjects and 35 consecutive patients with constipation (>1 year),vith anorectal manom etry and balloon expulsion test, Symptoms were assessed from diary car ds. Patients found to have obstructive defecation were offered biofeed back therapy, After treatment, their defecation dynamics and symptoms were reassessed. Results: Eighteen patients had obstructive defecation and 17 had normal defecation dynamics (nonobstructive). Five normals (20%) exhibited obstructive pattern but only one failed to expel ballo on. In the obstructive group, during straining, the intrarectal pressu re and defecation index were lower (p < 0.05), and anal residual press ure was higher (p < 0.01) when compared with the nonobstructive group or normals, After biofeedback therapy, the intrarectal pressure and de fecation index increased (p < 0.02) and anal residual pressure decreas ed (p < 0.001); stool frequency, degree of straining, and bowel satisf action scores improved (p < 0.05); 67% stopped laxatives and 11 patien ts discontinued stooling with digitation, Conclusion: Patients with ob structive defecation showed impaired rectal contraction, paradoxical a nal contraction, or inadequate anal relaxation, These features suggest that rectoanal coordination was impaired. Biofeedback therapy rectifi ed these pathophysiological disturbances and improved constipation. (C ) 1998 by Am, Cell, of Gastroenterology.