Bladder response to acute sacral neuromodulation while treating rats in different phases of complete spinal cord injury: a preliminary study

Abstract

Background:Compared to conventional therapies, sacral neuromodulation (SNM) may offer an alternative, non-destructive treatment for SCI patients with bladder dysfunction. Understanding bladder response to SNM treatment for SCI in different phases may yield new insights for innovative use of this promising technique.Materials and Methods:Female Sprague-Dawley rats were used in this study to examine the effects of acute SNM on bladder reflex in complete SCI rats. All rats were anesthetized and set up for continuous saline infusion. Acute SNM treatment was implemented for about 6 hours for each rat. Cystometric parameters, including time between contractions, contraction duration, bladder peak pressure, and number of uninhibited contractions, were analyzed and compared within rats before and after SNM treatment.Results:For the spinally transected rats during early phase (less than two weeks post spinalization), the time between contractions and contraction duration both increased after SNM treatments, yet the increased amplitude was about or less than 20%. For the spinally transected rats with a longer days survival (about two to four weeks post spinalization), the time between contractions and contraction duration substantially increased after SNM treatment and the changes for their average values were more than 90%. For the spinally transected rats with a much longer days survival (more than five weeks post spinalization), the time between contractions and contraction duration increased after SNM treatments, yet the magnitude of changes were less than 30%.Conclusion:The present study suggested that the significant effectiveness of SNM for complete SCI played its role after the spinal shock phase and prior to the development of detrusor overactivity. It indicated that the time point of SNM treatment is necessary to be paid attention.

Effect of Early Sacral Neuromodulation on Bladder Function in a Rat Model of Incomplete Spinal Cord Injury Due to Focal Contusion

“…As for the effect on the interval between voiding contractions, our experiment demonstrated that the interval decreases significantly to the level of the CTR group following SNM treatment. However, as the effect of SCI on the interval might depend on the conditions of each animal experiment , more study is needed to determine the influence of SNM on the interval between voiding contractions.…”

“…SNM was conducted for a period of two weeks or three weeks in the previous animal studies. Moreover, the stimulation duration per day was also variable between studies . In the present study, we performed the stimulation 30 min a day for a period of four weeks.…”

“…In the previous experiments with rats, various lumbar/sacral nerves, such as L6, S1, or S3, were selected for stimulation . We determined to use S3 nerve for stimulation to reproduce the clinical application of SNM on S3 foramen.…”

“…In addition, early SNM placement might preserve nerve plasticity and enhance pelvic organ functionality in patients with complete SCI . The degree of the effects of SNM on recovery from bladder dysfunction was reported to be greatest when applied 2–4 weeks after spinalization in a rat model . Therefore, SNM could be one of the options to consider for patients in the early phase of SCI to help them recover from bladder dysfunction.…”

Neuromodulation of pelvic nerve during early phase of spinal cord injury in rats using implantable prototype devices - a preliminary study

“…Therefore, not much is understood about the usefulness of SARS in the acute stages of SCI. Neuromodulation studies for bladder dysfunction in animal models of SCI are also mostly focused on the chronic stages of SCI where bladder hypertrophy, overactive bladder, and detrusor-sphincter dyssynergia are observed [12][13][14][15] . These animal studies typically used manual expression (or the Credé maneuver) twice to three times daily, whereby pressure is applied gently to the abdominal area over the bladder to overcome urethral pressure to enable urine release, for early post-operative bladder management.…”