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

Objective: To investigate the therapeutic effects of repeated detrusor onabotulinumtoxinA injections on urinary incontinence and renal function in patients with chronic spinal cord injuries (SCI).

Methods: 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.

Results: 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.

Conclusions: 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.