Cauda equina syndrome: false-positive diagnosis of neurogenic bladder can be reduced by multichannel urodynamic study.

Background: The present consensus suggests urgent surgical decompression if clinical features of cauda equina syndrome (CES) are supported by MRI evidence of pressure on cauda equina. However, clinical diagnosis has a high false-positive rate and MRI is a poor indicator. Though urodynamic studies (UDS) provide objective information about the lower urinary tract symptoms experienced by patients including neurogenic bladder, its role in the diagnosis of CES is not established.

Objective: To evaluate the ability of an objective urological assessment protocol using uroflowmetry + USG-PVR as screening test and invasive UDS as confirmatory test in patients with suspected CES to rule out neurological impairment of the bladder function.

Methods: A retrospective study was conducted on all patients who were referred to our institution with equivocal findings of cauda equina syndrome from January 2014 to December 2018 with positive MRI findings. An algorithm using multichannel UDS was followed in all the included patients.

Results: Out of 249 patients who fulfilled the inclusion criteria, 34 patients (13.65%) had normal uroflowmetry and USG-PVR findings; 211 patients underwent the invasive UDS. Only 141(57.6%) patients out of 245 patients had neurovesical involvement due to compression of cauda equina; 67 patients were treated conservatively using the objective protocol. Only one patient treated conservatively had to undergo emergency decompression for deterioration in symptoms.

Conclusions: Multichannel UDS provides an objective diagnostic tool to definitively establish the neurovesical involvement in CES. Utilising multichannel UDS as an adjunct to clinical findings avoids the probability of false-positive diagnosis of CES. These slides can be retrieved under Electronic Supplementary Material.