Botulinum Toxin Type A for Refractory Neurogenic Detrusor Overactivity in Spinal Cord Injured Patients in Singapore

Abstract

Introduction: Managing neurogenic detrusor overactivity (NDO) successfully in spinal cord-injured patients is a challenge. The aims of preserving kidney function by achieving safe bladder pressures with anticholinergic medication often leave a significant proportion of patients with side effects. Botulinum toxin type A has been shown to be a promising alternative. Materials and Methods: Spinal cord injury patients who had NDO, on clean intermittent self-catheterisation, and were refractory to oral medications, were recruited. Three hundred units of botulinum toxin type A (Botox) in 30 mL NaCl solution were injected under cystoscopic guidance into the bladder. Results: Fifteen patients were recruited of whom 9 were tetraplegic and 6 were paraplegic. Eleven (73.3%) had complete injuries. There was a significant reduction in the mean number of leakages from 3.75 ± 1.79 pre-injection to 0.67 ± 1.31 and 1.5 ± 1.5 at 6 and 26 weeks post-injection, respectively (P <0.05). Seventy-five per cent, 37.5% and 50% were completely dry at 6, 26 and 39 weeks post-injection, respectively. The mean maximal catheterisable volume increased from 312.3 ± 145.6 mL pre-injection to 484.6 ± 190 mL, 422.3 ± 157.3 mL and 490.0 ± 230.4 mL at 6, 26 and 39 weeks post-injection, respectively (P <0.005). Maximum detrusor pressure decreased significantly from 66.3 ± 22.6 cmH2O to 21.2 ± 23.1 cmH2O and 33.6 ± 30.2 cmH2O at 6 and 26 weeks post-injection, respectively (P <0.05). The volume at which reflex detrusor contractions first occurred increased from 127.8 ± 57.5 mL pre-injury to 305.7 ± 130.8 mL at 6 weeks and 288.3 ± 13.0 mL at 26 weeks post-injection (P <0.05). Mean cysometric bladder capacity increased from 187.8 ± 69.2 mL to 305 ± 136.4 mL and 288.3 ± 13.0 mL at 6 and 26 weeks post- injury, respectively (P <0.05). Sixty per cent of patients were completely off medications at 6 and 26 weeks post-injection. One patient had urinary tract infection and 1 experienced autonomic dysreflexia during cystoscopy. Satisfaction levels increased from 4.3 ± 2.3 pre-injury to 7.2 ± 1.9 and 7.3 ± 2.3 at 6 weeks and 26 weeks, respectively. This also correlated with fewer leakages. Conclusion: Botulinum toxin type A injected into the detrusor is safe and efficacious for spinal cord injured patients with refractory detrusor overactivity. This effect is maintained at 26 weeks post-injection. Key words: Anticholinergics, Spinal cord injury, Urodynamics, Voiding