Efficacy of ultrasound-guided transabdominal intradetrusor botulinum toxin injection for detrusor overactivity after spinal cord injury.

[OBJECTIVE] To compare the efficacy and safety of ultrasound-guided transabdominal versus transurethral cystoscopic botulinum toxin type A (BoNT-A) injection for treating detrusor overactivity (DO) following spinal cord injury (SCI).

[METHODS] In this retrospective cohort study, we analyzed clinical data from 60 SCI patients with DO treated at Hangzhou Third People's Hospital between January 2020 and June 2025. Patients were divided into two groups: the transabdominal ultrasound-guided group (n = 30) received transabdominal BoNT-A injection (100U, 4-point technique), while the cystoscopic group (n = 30) underwent standard transurethral cystoscopic injection (100U, 20-point technique). Primary outcomes included maximum cystometric capacity (MCC), detrusor pressure at maximum flow rate (Pdet.Qmax), and 24-h urinary incontinence episodes, and key storage-phase safety parameters (detrusor leak point pressure [DLPP] and bladder compliance), assessed at baseline, 1 month, and 6 months post-treatment. Secondary measures comprised the Neurogenic Bladder Symptom Score (NBSS) and Urinary Distress Inventory (UDI-6). Procedure-related complications, visual analog scale (VAS) pain scores (excluding ASIA A patients), and treatment acceptance were recorded within 30 min post-intervention by trained nurses using standardized protocols.

[RESULTS] The 60 enrolled patients showed well-matched baseline characteristics (all P > 0.05). At 1-month follow-up, both groups demonstrated significant improvements in urodynamic parameters (MCC: + 160.87 ± 177.89 mL vs + 157.46 ± 165.53 mL; Pdet.Qmax: -14.70 ± 11.43 cmH₂O vs -14.22 ± 12.17 cmH₂O) and incontinence frequency (-2.72 ± 1.07 vs -2.78 ± 1.15 episodes/day) compared to baseline (all P < 0.05), with no between-group differences in improvement magnitude (all P > 0.05). Critically, storage-phase safety also improved, with significant reductions in DLPP and increases in bladder compliance in both groups (all P < 0.05). The ultrasound-guided group showed superior safety profiles: lower pain scores (3.02 ± 1.27 vs 4.22 ± 1.41, P = 0.003), reduced hematuria (6.67% vs 50.00%, P < 0.001), and fewer urinary tract infections (3.33% vs 20.00%, P = 0.031). Treatment acceptance was significantly higher in the ultrasound-guided group (8.28 ± 1.54 vs 5.86 ± 2.19, P < 0.001). Therapeutic effects remained significantly better than baseline at 6-month follow-up despite partial attenuation (all P < 0.05).

[CONCLUSION] Ultrasound-guided transabdominal BoNT-A injection is as effective as the cystoscopic approach for SCI-induced DO, but offers a superior safety profile and greater patient acceptance. The technique also significantly improves storage-phase safety parameters, making it an advantageous alternative, especially for patients unsuitable for cystoscopy.