Can digital rectal examination be used to detect cauda equina compression in people presenting with acute cauda equina syndrome? A systematic review and meta-analysis of diagnostic test accuracy studies

Abstract

Background: Digital rectal examination (DRE) is a commonly used test to help identify people with cauda equina compression (CEC).

Objective: To determine the diagnostic accuracy of DRE in assessment of anal tone, squeeze, sensation and reflexes, as predictors of CEC.

Design: A systematic review to investigate the diagnostic accuracy of DRE to detect CEC compared with lumbar Magnetic Resonance Imaging (MRI).

Method: Six electronic databases were searched from inception to 6 July 2020 for studies published in English. Two assessors independently performed screening, data extraction and risk of bias assessment (QUADAS-2). Meta-analysis was performed using STATA-16.

Results: Six studies were included (n = 741). The sensitivity of anal tone was low across all studies (range: 0.23 to 0.53) with moderate quality evidence against the use of DRE of anal tone. One study on anal sensation found no correlation with CEC using Kendall's tau test: p = 0.102 and another found sensation had low test accuracy. One study identified sensitivity: 0.29 and specificity: 0.96 for anal squeeze, while another identified sensitivity: 0.38 and specificity: 0.6 for anal reflexes.

Conclusion: The diagnostic accuracy of DRE of anal tone to detect CEC is low and carries a high risk of false reassurance. It is therefore not recommended in any clinical setting. More research is needed to determine the diagnostic accuracy of DRE of anal squeeze, sensation and reflexes and if done the results should be interpreted with caution.

Keywords: Anal squeeze; Anal tone; Cauda equina compression; Cauda equina syndrome; Diagnostic accuracy; Digital rectal examination.