Time Factor and Disc Herniation Size: Are They Really Predictive for Outcome of Urinary Dysfunction in Patients With Cauda Equina Syndrome?

BACKGROUND: Timing of surgery and the importance of the size of disc prolapse in cauda equina syndrome (CES) remain controversial. OBJECTIVE: To investigate whether there is a relationship between postoperative urinary function, preoperative duration of neurogenic lower urinary tract dysfunction (NLUTD), and the level of canal compromise. METHODS: Seventy-one patients operated for CES were prospectively identified between 2010 and 2013. Fifty-two cases with preoperative NLUTD were included. The "Prolapse: Canal ratio" (PCR) was calculated as a proportion of cross-sectional area of disc prolapse on total cross-sectional area of spinal canal. RESULTS: Median of preoperative duration of NLUTD was 72 h (48; 132) and period from first assessment to surgery 10.5 h (7; 18.5). Urinary incontinence was seen in 46.2% of patients, 38.4% had painless retention and 15.4% had painful retention. In 38.5% of cases, urinary symptoms persisted for more than 20 mo postoperatively. There was no correlation between duration of preoperative NLUTD and urinary dysfunction persistence (P = .921). The outcome was not significantly influenced by having surgery more than the 48 h after presentation (P = .135). Preoperative incontinence persisted in 58% and painless retention in 30% of cases. The mean PCR was 0.6 ± 0.18. There was no correlation between PCR and outcome (P = .537) even after adjusting for duration of preoperative NLUTD (P = .7264). CONCLUSION: No significant correlation was demonstrated between the preoperative duration of urinary dysfunction, the size of disc herniation relative to size of spinal canal, and postoperative urinary function in a large consecutive series of patients with CES.