['To investigate which urodynamic parameters are associated with renal deterioration over a median of 41 years follow-up after traumatic spinal cord injury.', 'Medical records of patients with a traumatic spinal cord injury sustained 1944-1975 were reviewed from time of injury until 2012. Patients who attended regular renography and/or renal clearance examinations and had minimum one cystometry and pressure-flow study were included. Renal deterioration was diagnosed as split renal function ≤30% in one kidney or relative glomerular filtration rate ≤51% of expected according to age and gender. Detrusor function, presence of detrusor sphincter dyssynergia, maximum detrusor pressure, post-void residual volume, and cystometric bladder capacity were obtained. In patients with detrusor overactivity, a detrusor overactivity/cystometry ratio was calculated using duration of detrusor contraction(s) during filling cystometry divided by total duration of filling cystometry.', 'A total of 73 patients were included in the study, and the median follow-up time was 41 years after injury (range 24-56). Sixty-four patients (88%) used reflex triggering or bladder expression as bladder emptying method for the longest period after injury. During follow-up 60% changed to clean intermittent catheterization. The majority of the patients (68%) had neurogenic detrusor overactivity. In 35 patients, a detrusor-overactivity/cystometry ratio could be calculated and a detrusor overactivity/cystometry ratio\u2009>\u20090.33 was significantly associated with renal deterioration (P\u2009<\u20090.02). No significant association was found between maximum detrusor pressure or other urodynamic parameters and renal deterioration.'] Is renal deterioration after spinal cord injury associated with length of detrusor contractions during cystometry-A study with a median of 41 years follow-up?