Assessment of anal sphincter tone is a critical part of anorectal examination, yet no standardized, quantifiable method for describing anal sphincter tone on digital rectal examination exists. We developed a novel scoring system for anal sphincter tone using a scale of 0 to 5 for both resting pressure and squeeze pressure. The score ranges from 0 = no discernable pressure to 5 = extremely tight and 3 = normal. We hypothesized that the digital rectal examination scoring system (DRESS) score would correlate with anorectal manometry pressures.
Three hundred three patients (mean age, 51 y; range, 28–86 y) who had a DRESS score and a concurrent manometry test (1998–2008) were identified from a prospective database. Means of 4 quadrant manometry at rest and with squeeze were compared with the resting pressure and squeeze pressure DRESS scores at each point from 0 to 5. Box plots for manometry results by DRESS score were graphed. ANOVA using a significance level of α = .05 tested whether each of the DRESS scores were different from one another. Spearman rank correlation coefficients assessed associations between manometry and DRESS results.
Manometric pressures (mmHg; mean ± SEM) for DRESS resting pressure values 0 to 5 were 20.6 ± 2.1, 38.5 ± 2.0, 47.8 ± 1.6, 72.3 ± 1.5, 94.4 ± 2.9, and 128.0 ± 6.7, respectively. Pressures for DRESS squeeze pressure values 0 to 5 were 45.9 ± 5.6, 66.5 ± 3.2, 108.2 ± 4.9, 156.3 ± 4.5, 238.6 ± 9.8, and 368.2 ± 49.1. Box plots demonstrated clear differences between each DRESS score and positive progression from 0 to 5 for both resting pressure and squeeze pressure. ANOVA analysis showed a significant difference in mean manometry measurements at all levels of digital rectal examination, both for resting pressure and squeeze pressure (P < .001). Spearman rank correlations showed a strong positive correlation between the DRESS values and manometry pressures with coefficients of 0.82 for resting pressure and 0.81 for squeeze pressure.
The DRESS score correlated very well with manometry pressures for resting pressure and squeeze pressure. The DRESS system may be a useful description of anal sphincter resting pressure and squeeze pressure in the clinical setting. Further validation may support adoption of the DRESS system as part of the standard anorectal examination.
1 The Division of Colon and Rectal Surgery, Tufts Medical Center, Boston, Massachusetts
2 The Division of Colon and Rectal Surgery, The George Washington University, Washington, DC
Financial Disclosures: None reported.
Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Hollywood, FL, May 2 to 6, 2009.
Correspondence: Bruce A. Orkin, M.D., Division of Colon and Rectal Surgery, Tufts Medical Center, 800 Washington Street, Box 6190, Boston, MA 02111. E-mail: firstname.lastname@example.org