The aim of the study was to evaluate whether anorectal manometry (ARM), which is used to test the rectoanal inhibitory reflex (RAIR), is a safe alternative for reducing the number of invasive rectal suction biopsy (RSB) procedures needed to diagnose Hirschsprung disease (HD).Methods:
Between 2010 and 2017, we prospectively collected the ARM results of 105 patients suspected of having HD. Following the outcome, the patients either underwent additional tests to confirm HD or they were treated conservatively. Primary ARM-based diagnoses were compared with the definitive diagnoses based on the pathology reports and/or clinical follow-ups. Additionally, we analyzed whether modifications to our ARM protocol improved diagnostic accuracy.Results:
The sensitivity of ARM and RSB was comparable (97% vs 97%). The specificity of ARM, performed according to our initial protocol, was significantly lower than that of RSB. After we modified the protocol the difference between the specificity of ARM and RSB was no longer statistically significant (74% vs 84%, respectively, P = 0.260). The negative predictive value of ARM was 100%, while their positive predictive value was significantly lower than that of RSB (56% vs 97%, P < 0.001).Conclusions:
ARM is a viable screening tool for HD and, provided it is performed properly, it can be used to exclude HD with absolute certainty. By contrast, an absent rectoanal inhibitory reflex on ARM should always be followed by an RSB to confirm the diagnosis of HD. Using ARM as the diagnostic of first choice could reduce the number of invasive biopsies.