Role of 3D high resolution anorectal manometry compared to conventional technique in management of constipation and fecal incontinence in children

Background: Anorectal manometry is a valuable tool for objective assessment of motility motor and sensory function of the anorectum. The aim of this study was to investigate role of water-perfused (WP) three dimensional high-resolution anorectal manometry (3D-HRARM) compared to WP conventional manometry (CM) in the management of chronic idiopathic constipation (CIC) and faecal incontinence (FI) in children. Methods: This was a retrospective review of 122 consecutive children, who had WP 8-channel CM or 24 channel 3D-HRARM and endosonography under ketamine anaesthesia from September 2012 to February 2019. All patients had a validated symptom severity score questionnaire ranging from 0 (best) to 65 (worst). Mann-Whitney-U test and Spearman rank test were used and p < 0.05 was considered significant. Results: Subjects were divided according to investigation: CM group ( n = 75) and 3D-HRAM ( n = 47), who were otherwise comparable. Median anal resting pressure was 50 mmHg and rectoanal inhibitory reflex (RAIR) threshold volume was 10mls across the entire cohort. There were no significant differences in resting pressure or RAIR threshold when using conventional or 3D-HRARM. Rectal capacity was significantly higher in the CM group ( p = 0.002). Rectal capacity and internal anal sphincter (IAS) thickness positively correlated with symptom severity, duration and patient age. 3D-HRARM provided a more detailed depiction of the anorectal pressure profile. Botulinum toxin was injected into the external anal sphincter (EAS) muscle ( n = 75, 61%) and an anterograde colonic enema (ACE) stoma was needed subsequently in 19 (16%) to treat recurrent constipation and soiling symptoms. Rectal biopsy was done in 43(35%) patients, if RAIR was absent or inconclusive. Conclusion: CM and 3D-HRARM are comparable in terms of resting pressure and RAIR threshold. 3DHRAM is safe and provides detailed functional morphology of anal sphincters and it is useful to understand underlying pathophysiology of constipation and faecal incontinence in children and plan further treatment. Level of Evidence: Level I