The Effectiveness Of Digital Anal Dilatation In Preventing Anal Strictures After Anorectal Malformation Repair

Abstract

Background: Anal dilatation is performed after repair of anorectal malformations(ARMs) and is vital in prevention of anal stricture formation. The ideal protocol utilizes Hegar dilators. In our setup, few parents will acquire Hegar dilators for home based anal dilatation but majority will use fingers as an alternative. The basis of this study was to determine the effectiveness of digital anal dilatations in preventing anal strictures.

Materials and methods: This was a descriptive cross-sectional study carried out at Kenyatta National Hospital (KNH) which recruited children post ARM repair undergoing digital anal dilatation. The diameters of the digits used for anal dilatation were assessed for adequacy using the desired anal size as a reference point. The main outcome variable was the presence of anal strictures. Data were entered in a data collection sheet and analyzed by use of SPSS (V.21.0 Chicago, Illinois). Chi-square test and Fisher's exact test were used to ascertain association among variables. A P-value of less than 0.05 was considered statistically significant.

Results: 50 patients with ARM post repair were recruited in the study. The rate of occurrence of anal stricture was 22%. Among the participants with anal strictures, only 27% were compliant to the dilatation regimen while 73% reported noncompliance. The mean diameter(mm) of the dilating digits at the level of the middle phalanx was Index finger (15.4 ± 0.58), middle finger (15.2 ± 0.61), ring finger (14.2 ± 0.71), small finger (12.5 ± 0.91) and thumb (17.6 ± 0.78). 46% of the participants were dilated with appropriately sized digits. The remainder had dilatations done with larger (22%) or smaller digits (32%). Notably, anal strictures occurred in participants who were dilated with inappropriately sized digits (P = 0.001).

Conclusion: Digital anal dilatation is safe and effective as a mode of anal dilation in the setting of compliance to a strict dilatation protocol, daily frequency of dilations and use of appropriately sized digits. Owing to the variability in the finger size, we recommend that digits be calibrated and education given to the caregivers on the use of the appropriately sized digit.

Level of evidence: Treatment study. Level III.