Bladder compliance (BC) describes the relationship between the change in bladder volume and change in detrusor pressure  .
Botulinum toxin A (Botox®, Allergan,
This retrospective study reflects 72 SCI impatients from 2011 to 2016. There were 62 males and 10 females, age range 18 - 52 years at first injection, with a mean age of 28.51 years (Table 1). All patients possessed low BC (<20 ml/cmH2O)  on clean intermittent catheterization, and had an inadequate response to or are intolerant of an anticholinergic medication. All patients were regularly received urodynamic examinations. After informed consent and the approval of the ethics committee, the patients were offered the possibility of BTX-A injection before considering more invasive procedures.
Injections were performed with no anesthesia or under epidural anesthesia in the operating room with a 21 F rigid cystoscope (Ackermann,
Table 1. Demographic characteristics of the participants.
Abbreviations: SCI = spinal cord injury; AIS = American Spinal Injury Association Impairment Scale (AIS).
Figure 1. Location of BTX-A injection sites.
experience in BTX-A injections. A catheter had been inserted for 1 - 3 days and antibiotics (except aminoglycosides) were administered for three days.
The follow-up with ultrasound, urodynamics, and clinical evaluation was made at 12 weeks after the procedure. Urodynamic parameters include maximum detrusor pressure (Pdetmax), bladder compliance (BC). Related adverse events were recorded.
Statistical analysis was performed using the SPSS 13.0 soft-ware package (SPSS, Inc.,
The results of this study are shown in Figure 2. Pdetmax (Mean maximum detrusor pressure before the injection 51.02 cmH2O,mean Pdetmax after the injection 28.31 cmH2O), BC (Mean bladder compliance, before the injection 3.64 ml/cmH2O, after the injection 10.08 ml/cmH2O). During the first week after injection, 12 patients had mild transient haematuria for 1 - 2 days. No patients required medication or surgical intervention.
Low Bladder compliance (BC) commonly occurs in patients with spinal cord injury (SCI). The clinical application of BTX-A is now a common technique in several urological medical fields for neuropathic and non neuropathic patients. BTX-A blocks acetylcholine release by binding, at the presynaptic level, to SNAP-25, a cytoplasmic protein on the cell membrane, which plays a major role in acetylcholine release  . BTX-A has been known to reduce signs and symptoms
Figure 2. Videourodynamic parameters of patients at baseline and 12 weeks follow-up a significant improvement (*P < 0.05) was noted at 12 weeks.
of neurogenic incontinence, and significantly improve health-related quality of life  .
In our study, intradetrusor BTX-A injections achieved a low pressure bladder to preserve of the upper tract function for patients with low BC. These findings were supported by improvements in detrusor pressure and bladder compliance. A significant decrease in Pdetmax compared with baseline measurement were observed (28.31 cmH2O vs 51.02 cmH2O, P = 0.041). Mean Pdetmax reduced to be below 40 cmH2O at 12 weeks follow up. In 1988, Wang SC  reported that for patients with bladder pressures above 40 cmH2O, 81% were potentially dangerous to renal function in five years follow-up. As a result, a significant average increase of BC (before the injection: 3.64 ml/cmH2O, after the injection: 10.08 ml/cmH2O).
The urodynamic reported changes with botulinum toxin type A monotherapy were translated into significant improvements in health-related quality of life throughout the treatment period. These results imply that the effect of a botulinum toxin type A intradetrusor injection continued during the study period, even without concomitant use of anticholinergics.
In our study, the complications directly related to the BTX-A injection procedure were mild transient hematuria and bladder discomfort during the first week after injection. All patients did not require any medication or surgical intervention.
A limitation of this study is that number of patients was relatively fewer. Therefore, further studies are warranted.
Intradetrusor BTX-A injection was effective and safe for patients with low BC secondary to SCI.
This study was supported by Medical Scientific Research Foundation of Guangdong Province, China (grant number B2017040).
Conflict of Interest Statement
The authors declare no conflict of interest.
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