Effect of repeated detrusor onabotulinumtoxina injections on bladder and renal function in patients with chronic spinal cord injuries

Abstract

To investigate the therapeutic effects of repeated detrusor onabotulinumtoxinA injections on urinary incontinence and renal function in patients with chronic spinal cord injuries (SCI). Patients with suprasacral SCI were enrolled. OnabotulinumtoxinA 200 U detrusor injections were repeated every 6 months for four times. Patients were instructed to perform clean intermittent catheterization during the treatment and follow-up periods. Videourodynamic study and 99mTc-DTPA renal scanning for glomerular filtration rate (GFR) were performed at screening and every 3 months to assess the therapeutic effects on bladder and renal function. Quality of life was measured by the UDI-6, IIQ-7, and self-assessed QoL indices. Adverse events were also recorded. A total of 33 patients completed the study, 30 had improvement in incontinence grade (n = 18) or became completely dry (n = 12) after initial and subsequent onabotulinumtoxinA injections. Mean bladder capacity increased from 207 ± 111 to 412 ± 33 ml and mean detrusor pressure decreased from 39.8 ± 21.7 to 20.6 ± 19.1 cmH(2) O (all P < 0.05). However, the mean GFR decreased from 93.4 ± 20.4 to 83.5 ± 24 ml/min (P = 0.028). A significant reduction in GFR was noted in patients with bladder compliance that increased by <10 cmH(2) O (P = 0.002) and in patients with Pdet decreased by <10 cmH(2) O after treatment (P = 0.036). All 30 patients with improvement in incontinence grade satisfied with treatment result. This pilot study revealed that repeated detrusor injections of 200 U onabotulinumtoxinA could reduce incontinence grade, increase bladder capacity, and decrease intravesical pressure but this study did not demonstrate an improvement in GFR over a 24-month period in patients with chronic SCI.