The Evaluation of Digital Rectal Examination for Assessment of Anal Tone

Abstract

Introduction Cauda equina syndrome represents the constellation of symptoms and signs resulting from compression of lumbosacral nerve routes. Combined with subjective neurological findings, a reduction in anal tone is an important sign deeming further imaging necessary. Digital rectal examination (DRE) is an invasive procedure used to assess anal tone despite debated accuracy. Our main objective was to investigate the validity of DRE for assessment of anal tone. Materials and Methods Total 75 doctors completed a questionnaire documenting their grade, especiality, and experience in performing DRE. A model anus, using a pressure transducer surrounding an artificial canal, was assembled and calibrated. Participants performed four DREs on the model (with a break between attempts), and predicted tone as “reduced” or “normal” (35 and 60 mm Hg respectively), followed by a “squeeze” test. Total 30 health care assistants (HCAs) partook as a control group with no training in DRE. Results In each attempt 60, 61, 63, and 72% of doctors correctly identified the anal tone, respectively (average accuracy: 64%). HCAs had an identical average accuracy of 64%. Total 100% of participants correctly felt the squeeze test. For doctors no correlation was found between confidence in assessing anal tone using DRE and a correct result. Total 71% had received previous training in DRE with 64% of these taught how to assess anal tone. Total 43% of doctors felt that further training would be beneficial. Conclusion The results demonstrate that accuracy in assessing anal tone using DRE is limited with overall correctness of 64%. Poor correlation exists between perceived level of skill and study result. Doctors were not significantly more able than HCAs to detect correct tone. Therefore, DRE for the assessment of anal tone is not a wholly accurate tool. A squeeze test may be of greater value if interpreted correctly. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared