A retrospective study of intravesical botulin toxin type A in children with refractory detrusor overactivity

Detrusor overactivity (DO) is a common urodynamic manifestation of lower urinary tract dysfunction in children, which seriously affects the health of patients. Intravesical injection of botulinum toxin type A (BTX-A) is a minimally invasive alternative therapy for children with small bladder capacity or DO who fail to respond to drug therapy. However, BTX-A's safety, efficacy, and possible influencing factors for children still need to be further studied. This was a uncontrolled retrospective study, which was made on 54 children with DO (average age, 11.8 ± 4.4 years), including 24 males (44.4%) and 30 females (55.6%), due to neurogenic and non-neurogenic disorders. All children were treated in the First Affiliated Hospital of Zhengzhou University from January 2020 to August 2025. Urotherapy and drug treatments were ineffective in all children, who then received intravesical injections of BTX-A. The urodynamics (UDS) examination was performed at 1 week before treatment and 3 months after treatment, and the overactive bladder symptom score (OABSS) and incontinence specific quality of life (I-QOL) were collected. Perioperative and postoperative adverse events were also recorded. A global response assessment (GRA) score of ≥ 2 at 3 months postoperatively was defined as an effective treatment. Patients were divided into the effective group and the ineffective group to explore possible influencing factors affecting the outcome of BTX-A treatment, such as age, gender, and preoperative urodynamic parameters. An effective case is defined as the GRA score ≥ 2, and at the same time meeting at least one of the following objective improvement criteria: (1) The OABSS score decreased by ≥ 3; (2) The number of urinary incontinence episodes in 24 h decreased by ≥ 50%; (3) The DLPP decreased to < 40 cmH2O. The ineffective group consists of those who do not meet the above criteria or whose condition worsens. The bladder compliance (BC), bladder capacity ratio (BCR, measured/expected bladder capacity), OABSS score, and I-QOL score of patients significantly improved after BTX-A injection (all P < 0.05). 70.4% of the patients (38/54) were satisfied with BTX-A treatment. The main adverse event during the follow-up was a temporary increase in post-void residual (PVR) volume after injecting BTX-A (19/54, 35.2%), which was alleviated by the Crede action or clean intermittent catheterization. In group study, there was significant difference in age [13.18 ± 4.34 years vs. 8.56 ± 2.58 years, t = 2.383], preoperative BC [17.18 ± 13.51 mL/cmH2O vs. 5.20 ± 3.86 mL/cmH2O, t = 3.470], and preoperative detrusor leak point pressures (DLPP) [27.08 ± 9.76 cmH2O vs. 49.56 ± 36.38 cmH2O, t = - 3.558] between effective group (38/54, 70.3%) and ineffective group (16/54, 29.6%) (P < 0.05). The differences in preoperative BCR, PVR, voiding efficiency, and gender were not statistically significant between the two groups (P > 0.05). In this study, intravesical injection of BTX-A for the treatment of children with refractory DO was effective and had few complications. Young age, poor BC, and high DLPP at treatment are associated with poor prognosis of BTX-A treatment.