A Systematic Review of the Value of a Bladder Scan in Cauda Equina Syndrome Diagnosis

Cauda equina syndrome (CES) is one of the emergency conditions that can lead to devastating permanent functional disabilities, if misdiagnosed. Multiple studies have questioned the reliability of clinical assessment in diagnosing CES, whether some of the features should be considered to be potential red flags. Bladder dysfunction can reflect CE compromise. The post-void residual (PVR) volume bladder scan is useful in CES diagnosis, but to date there has been no single systematic review supporting its use. Furthermore, there is no clear cut-off point to consider PVR statistically significant. The aim of the study is to perform a systematic review of the current evidence behind the use of the PVR bladder scan as a diagnostic tool for CES diagnosis. This was a comprehensive search using Medline, PubMed and Embase. All articles included post-void bladder scans with the mentioned clear cut-off volume as a diagnostic parameter. A total of five study articles from 1955 fit with our inclusion and exclusion criteria. The total number of patients who had a bladder scan was 531. CES was confirmed in 85 cases. Bladder scan diagnosed 70 cases and excluded 327. The best results for both sensitivity and specificity in correlation with the sample of the study were for PVR more than 200 ml. Measuring the post-void urine volume using a bladder scan is an essential tool in the diagnosis of CES. There is a significant correlation between the PVR volume more than 200 ml and higher sensitivity and specificity.