Early sacral neuromodulation ameliorates urinary bladder function and structure in complete spinal cord injury minipigs

Aims

To determine the effects of early sacral neuromodulation (SNM) and pudendal neuromodulation (PNM) on lower urinary tract (LUT) function, minipigs with complete spinal cord injury (cSCI) were analyzed. SNM and PNM have been proposed as therapeutic approaches to improve bladder function, for example after cSCI. However, further evidence on efficacy is required before these methods can become clinical practice.

Methods

Eleven adults, female Göttingen minipigs with cSCI at vertebral level T11-T12 were included: SNM (n = 4), PNM (n = 4), and SCI control (SCIC: n = 3). Tissue from six healthy minipigs was used for structural comparisons. Stimulation was started 1 week after cSCI. Awake urodynamics was performed on a weekly basis. After 16 weeks follow-up, samples from the urinary bladder were taken for analyses.

Results

SNM improved bladder function with better capacities and lower detrusor pressures at voiding and avoided the emergence of detrusor sphincter dyssynergia (DSD). PNM and untreated SCI minipigs had less favorable outcomes with either DSD or constant urinary retention. Structural results revealed SCI-typical fibrotic alterations in all cSCI minipigs. However, SNM showed a better-balanced distribution of smooth muscle to connective tissue with a trend towards the reduced progression of bladder wall scarring.

Conclusion

Early SNM led to an avoidance of the emergence of DSD showing a more physiological bladder function during a 4 month follow-up period after cSCI. This study might pave the way for the clinical continuation of early SNM for the treatment of neurogenic LUT dysfunction after SCI.