Spinal Cord Injury and Bladder Function

Neuroanatomy of Bladder Control

The sacral spinal cord segments S2-S4 contain the primary neural centers controlling bladder function, housing the parasympathetic neurons that regulate detrusor contraction and urethral sphincter coordination 1, 2
The thoracolumbar spinal cord (T10-L2) contains sympathetic pathways that contribute to bladder storage function and sphincter tone 2, 3
Higher spinal levels (above T10) affect bladder function through disruption of descending inhibitory pathways from the brain, leading to loss of voluntary control 4

Direct damage to sacral micturition center results in an areflexic or flaccid bladder with poor detrusor contractility 1, 5
Patients with sacral cord injuries typically experience urinary retention, overflow incontinence, and high post-void residuals 6
Voluntary control of the external urethral sphincter is lost in patients with sacral cord injuries 2
Disrupts coordination between detrusor contraction and sphincter relaxation, often leading to detrusor-sphincter dyssynergia in patients with thoracolumbar injuries 2, 3
Complete loss of voluntary control with preservation of spinal reflex arcs occurs in patients with cervical and upper thoracic injuries 4

Intermittent catheterization is recommended over indwelling catheters for bladder emptying in patients with neurogenic lower urinary tract dysfunction 6
Suprapubic catheterization is preferred over urethral indwelling catheters when chronic catheterization is necessary 6
OnabotulinumtoxinA injections are strongly recommended for patients with spinal cord injury or multiple sclerosis who have refractory neurogenic bladder symptoms 6

The level and completeness of injury significantly impact bladder function recovery 2, 3
Lumbar or conus medullaris injuries typically show greater neurologic recovery potential compared to thoracic injuries 3
The reappearance of voluntary external anal/urethral sphincter contraction correlates significantly with bladder function recovery 3