High-resolution Anorectal Manometry Findings in Dyssynergic Defecation

Introduction: Dyssynergic defecation (DD) is the most common disorder of defecation and affects up to 40% of patients with chronic constipation. Four types of DD have been defined by anorectal manometry, these are characterized by a paradoxical increase in anal pressure with (type I) or without (type II) adequate increase in rectal pressure and failure of reduction in anal pressure with (type III) or without (type IV) adequate increase in rectal pressure. It is unknown whether there are any differences between manometric parameters in DD types and the frequency of DD in our population. Methods: Study of patients who underwent high-resolution anorectal manometry for functional constipation during January 2013 to July 2015 in a tertiary referral center. For statistical analysis, the frequencies were expressed as percentages and comparative statistics by Student's T-Test and Wilcoxon rank test were applied, and relationships between manometric findings were evaluated by calculation of Spearman's correlation coefficient. P values < 0.05 were considered significant. Results: DD was found in 58 subjects, of which 81% (N = 47) were women. The average age was 42.95 ± 19.52. In the population with DD there was a positive correlation between the intrarectal pressure (IRP) and the anal canal length (r = 0.405 p = 0.002), the first sensation and height (r = 0.406, p = 0.002), the anorectal differential pressure (ARDP) and the anal relaxation percentage (r = 0.560, p < 0.001), the IRP and maximum sphincter pressure at rest MaxSPR (r = 0.480, p < 0.001), and in the IRP and the ARDP (r = 0.567, p < 0.001). The most common type of DD was the type I in 58.6% (N = 34), followed by type III in 19% (N = 11), Type II in 17.2% (N = 10) and Type IV in 5.2% (N = 3). Significant differences in the anal residual pressure between the group I and IV DD (103.25±46 vs 45.40±34 mmHg p < 0.05, see FIGURE1) were found. We found differences in the first sensation between DD subtypes according to gender (p < 0.05, see FIGURE2).Figure 1Figure 2Conclusion: DD is more common in women and type I is the most common in our population. The anal residual pressure distinguishes between the type I and the type IV. There are gender variations in rectal sensitivity among the dyssynergic defecation subtypes. We assume that these differences may be related to visceral hypersensitivity. The categorization of the types of DD perhaps will allow us to provide prognostic information and guide the direction of treatment.