OBJECTIVETo evaluate the urodynamic characteristics of the chronic impairment of cauda equina caused by lumbar disk herniation.

METHODSClinical data and urodynamic parameters of 67 male patients with lumbar disk herniation were retrospectively analyzed. Lower urinary obstruction was excluded from the cohort using the Lin-PURR analysis. Patients were divided into group A (normal detrusor function), group B (detrusor underactivity) and group C (detrusor areflexia) according to the detrusor contraction function analyzed in Lin-PURR. Clinical data and urodynamic parameters were analyzed statistically between these groups.

RESULTSThe category of the detrusor contraction function had a significant effect on the urodynamic parameters. There were significant differences in the maximum flow rate (Q(max)), maximum pressure (P(max)), pressure at the maximum flow (P(det Qmax)) and post-voiding residual urine (PVR) among group A, B and C. There were significant differences in the first sensation volume of the bladder and the maximum cystometric capacity between group A and C, B and C, but no significance was found between group A and B. There was no significant difference in age, disease duration, and compliance of the bladder among 3 groups.

CONCLUSIONSUrodynamic study is important in exploring the severity of the chronic impairment of cauda equina caused by lumbar disk herniation. Detrusor areflexia and loss of bladder sensory indicate more severe degree of impairment of the cauda equine. Q(max) and PVR are helpful in early diagnosis of the chronic impairment of cauda equina.