A meta-analysis of botulinum toxin sphincteric injections in the treatment of incomplete voiding after spinal cord injury.

OBJECTIVE

To conduct a systematic review and meta-analysis to examine the effect of injecting botulinum toxin A (BTX-A) into the detrusor sphincter on improving bladder emptying in individuals with spinal cord injury (SCI).

DATA SOURCES

MEDLINE, CINAHL, EMBASE, and PsycINFO databases were searched for all relevant articles published from 1980 to September 2011.

DATA SELECTION

All trials examining the use of BTX-A injections into the detrusor sphincter for the treatment for incomplete bladder emptying after SCI were included if at least 50% of the study sample comprised subjects with SCI, and if the SCI sample size was 3 or greater.

DATA EXTRACTION

A standardized mean difference (SMD) ± SE and 95% confidence interval (CI) were calculated for each outcome of interest, and the results were pooled using a fixed or random effects model, as appropriate. Outcomes assessed included postvoid residual urine volume (PRV), detrusor pressure (PDet), and urethral pressure (UP). Effect sizes were interpreted as small, 0.2; moderate, 0.5; and large, 0.8.

DATA SYNTHESIS

A relatively limited number of studies (2 randomized controlled trials, 6 uncontrolled trials) were identified. The 8 studies included results from 129 subjects. There was a statistically significant decrease in PRV at 1 month (SMD=1.119±.140; 95% CI, .844-1.394; P<.001), with a pooled mean PRV decrease from 251.8 to 153.0 mL. There was a moderate statistical effect on PDet (SMD=.570±.217; 95% CI, .145-.995; P=.009); pooled PDet decreased from 88.7 to 20.5 cmH(2)O. A large statistical effect size on UP (SMD=.896±.291; 95% CI, .327-1.466; P=.002) and an improvement from 119.7 to 102.3 cmH(2)O were seen. The systematic review also indicated a 50% reduction in urinary tract infections based on 3 studies. Discontinuation or reduction in catheter usage was reported in 4 studies after BTX-A.

CONCLUSIONS

Results of the meta-analysis indicate that BTX-A is effective in reducing PRV and demonstrating a statistically significant reduction in PDet and UP 1 month postinjection. However, the clinical utility of BTX-A is yet to be determined.