Long-term course of sacral anterior root stimulation in spinal cord injured individuals: The fate of the detrusor.

Aims: To investigate the long-term course of the detrusor pressure during sacral anterior root stimulation in spinal cord injury (SCI) patients.

Methods: Retrospective evaluation of 111 patients who had undergone sacral deafferentation and implantation of an anterior root stimulator at a single SCI rehabilitation center with a minimum follow-up time of 5 years.

Results: The median follow-up time was 11.7 years (range 5.0-24.9 years). The maximum detrusor pressure (Pdet_max) during stimulation was higher in men compared to women (P = 0.0004) and decreased over time (P = 0.0006). However, there were no significant (P ≥ 0.06) differences in the median Pdet_max during stimulation between the first measurement time point and any follow-up time point. The Pdet_max during stimulation decreased from 62 cmH O (95%CI 57-73 cmH O) to 53 cmH O (95%CI 47-69 cmH O) (P = 0.9). The time had also a significant effect on Pdet_max during the storage phase (P < 0.0001) and bladder compliance (P = 0.0007). The Pdet_max during the storage phase decreased, whereas bladder compliance increased during the follow-up period. There were no significant (P ≥ 0.1) changes over time in bladder capacity, the number of daily stimulations and the residual urine volume after voiding.

Conclusions: The detrusor pressure during sacral anterior root stimulation decreases over time in SCI individuals. However, the changes do not seem to be clinically relevant during the first decade after surgery.