Botulinum toxin injection is one of the main minimally invasive treatments for Overactive Bladder Syndrome (OAB). Postoperative urinary retention rates range from 5.4% to 43%, depending on the definition used across studies. The aim of this study was to evaluate functional and patient-reported outcomes of trigonal/peritrigonal (T/PT) versus standard detrusor (SD) botulinum toxin injections.

This single-center retrospective study included adult patients with idiopathic OAB unresponsive to pelvic floor muscle training (PFMT), anticholinergics, beta-agonists, percutaneous tibial nerve stimulation (PTNS), or sacral neuromodulation (SNM). Patients were eligible if they had non-neurogenic OAB treated with either 50U or 100U botulinum toxin injections. Two injection templates were compared: T/PT (2 trigonal and 8 peritrigonal injections) and SD (10 intramuscular detrusor injections). All patients underwent local anesthesia prior to the procedure. Outcome measures included acute urinary retention, chronic urinary retention, patient-reported outcome measures (Urinary Symptom Profile [USP] and Patient Global Impression of Improvement [PGI-I]), and treatment failure.

A total of 141 patients (123 females, 18 males) were included (74 T/PT; 67 SD). Botulinum toxin dosages administered were 50U (n=57; 30 T/PT, 27 SD) and 100U (n=84; 44 T/PT, 40 SD). In both groups, mean preoperative USP scores for OAB was 13/21; mean postoperative USP score for OAB 5/21 (p=0.21). The PGI-I rates for T/PT were 68%, 19%, 6%, 6%, 0%, 0%, and 1% for scores of 1 through 7, respectively. In the SD group, PGI-I rates were 51%, 34%, 7%, 8%, 0%, 0%, and 0%, respectively. PGI-I 1 or 2 rates between T/PT and SD groups were 86.5% (n=64) vs 85% (n=56), respectively (p=0.63). Acute urinary retention occurred in 7% (n=5) of the SD group but was not observed in the T/PT group (p=0,02). Chronic urinary retention rates were 1.7% in the T/PT group versus 36% in the SD group (p=<0.0001) Treatment failure rates were similar between groups (T/PT 9%, SD 10%) (p=1,0).

A significantly lower risk of urinary retention has been observerd while maintaining comparable subjective efficacy and treatment success. These findings support the potential safety advantage of targeting the trigonal/peritrigonal region.

Trigonal and peritrigonal botulinum toxin injections may be a suitable alternative to standard detrusor injections for idiopathic OAB, suggesting a lower risk of urinary retention with comparable clinical efficacy. Further studies are necessary to refine patient selection and assess the broader impact of this novel injection template