In the 200U group, PV was significantly reduced only at the six-month evaluation. The impact of intraprostatic injection of 100U and 200U of BoNT-A in IPSS, Qmax , PVR, PSA, and prostate volume was comparable, as seen in Table 2.Complications and their management are depicted in Table 3. No severe Mdm2 complication was observed. Two (5.8%) patients had transient hematuria requiring bladder irrigation, two (5.8%) had short-term urinary retention, and two had acute prostatitis (5.8%). One patient who initially had mild improvement of symptoms developed urinary retention 5 months after 100U BoNT-A injection, requiring transurethral resection of the prostate. The complication rate did not differ between the groups (P = 0.921). When present, pain was usually mild and no patient needed narcotic analgesics.

Table 3Complications after intraprostatic botulinum toxin injection for BPH.4. DiscussionThe efficacy of BPH treatment is primarily determined by the magnitude of symptom relief as well as improvement of urinary flow rates. In the present study, both BoNT-A doses promoted significant improvement of symptoms and increased flow rates that continued throughout the followup period of six months.Maria et al. [15] pioneered BoNT-A injection as a BPH therapy in a double-blind, placebo-controlled trial with 30 men who no longer responded to oral medication and refused surgical treatment. A total of 13 (86.7%) patients in the treated group and 3 (20.0%) in the control group had symptomatic improvement at the 2-month follow-up.

Patients in the treatment group had significant improvement in the maximum urinary flow rate, post-void residual urine volume, and IPSS score. Furthermore, PSA levels and prostate volume decreased significantly.Further studies have documented that intraprostatic BoNT-A injection is an efficient therapy, capable to improve LUTS and Qmax , as well as to reduce PVR [17, 21]. Our study has also shown these benefits up to 6 months after treatment. Additionally, we recorded that both doses (100U and 200U) promoted similar effects. One patient treated with 100U of BoNT-A developed urinary retention five months after the injection. Baseline characteristics of this patient included an IPSS score of 23, maximum flow rate of 3mL/s, PVR of 135mL, and a prostate volume 88mL. These clinical features characterize a severe case of BPH, which might explain why he failed BoNT-A therapy.

The patient was treated with transurethral resection AV-951 of the prostate with a favorable outcome.The effect of BoNT-A injection on prostate volume is controversial. Experimental studies demonstrated generalized atrophy and apoptosis of glandular and stromal components of the prostate [22�C24]. Previous series have shown different rates of prostate volume reduction, ranging from 13 to 54% [15, 16, 19, 21].