The therapeutic effects of repeated detrusor injections between 200 or 300 units of onabotulinumtoxinA in chronic spinal cord injured patients.

OBJECTIVES: To investigate the therapeutic effects of repeated detrusor onabotulinumtoxinA injections on treatment outcomes, quality of life (QoL), and glomerular filtration rate (GFR) in chronic spinal cord injured (SCI) patients with neurogenic lower urinary tract dysfunction and urinary incontinence.

MATERIALS AND METHODS: Patients with SCI who failed antimuscarinic treatment were enrolled. All patients had urodynamic detrusor overactivity (DO) or increased detrusor tonicity without anatomical bladder outlet obstruction or intrinsic sphincter deficiency. They were randomly assigned to receive 200-U or 300-U onabotulinumtoxinA detrusor injections every 6 months. The primary endpoint was 6 months after the second injection. The urodynamic parameters, QoL measures, and 99mTc renal scans were evaluated at baseline and every 3 months and compared between dosages.

RESULTS: A total of 72 patients were enrolled, including 43 men and 29 women and mean injury duration of 8.7 years. Among them, 38 patients received 200-U and 34 received 300-U onabotulinumtoxinA injections. At the end-point, the urodynamic parameters and incontinence severity improved significantly, without a significant difference between the two groups. QoL also improved in both groups, without differences between groups. Uninhibited DO improved more in 300-U group compared to 200-U group at end-point (P = 0.01). The GFR did not change significantly in either group. The most common complication was urinary tract infection, which occurred in one third of patients.

CONCLUSIONS: Either 200-U or 300-U repeated detrusor onabotulinumtoxinA injections improved incontinence, urodynamic parameters, and QoL in SCI patients with neurogenic DO. Renal function was maintained in patients receiving both dosage of repeated injections.