A Closer Look At Bladder Dysfunction In Persons With Lower Spinal Cord Peripheral Nerve Injuries

Cauda Equina Syndrome (CES) is a resulting cluster of issues a person experiences following damage to their nerves that exit the base of the spine in the shape of horse’s tail, hence the latin anatomical name of “cauda equina”. This important bundle of nerves gives sensation and motor supply to the pelvic organs and lower limbs. In addition, the cauda equina extends parasympathetic nerve supply to the bladder. When injured, persons with CES experience many functional problems with their bladder and/or bowels, decreased sensation in their crotch area, or sexual dysfunction.

Dr. Kim and his research collaborators in Cheonan, South Korea at the Department of Rehabilitation Medicine at Dankook University College of Medicine set forth to find what causes bladder dysfunction in persons with CES or lower spinal cord peripheral nerve injuries.

It is well recognized in the medical community that persons with CES will have bladder problems due to the injury to parasympathetic nerve supply to their bladder. This injury creates a subset of problems called “neurogenic bladder” making it difficult or impossible to urinate, or the opposite end of the urination spectrum making the bladder overactive. Dr. Kim’s team was specifically interested in delving into the cause of this hyperactive bladder or detrusor (muscle) overactivity (DOA).

The hyperactive bladder is problematic in 15-31 per cent of persons with cauda equine syndrome, but the mechanism that causes it cannot be explained solely by the level of the injured spinal nerve. The root causes of the variations in neurogenic bladder issues was the basis for this study. They aimed to further the science using clinical tests (think sophisticated measurements on urine output), radiological (like MRI images), and electrophysiology (like a nerve conduction test) on a group of 61 participants with CES and a hyperactive bladder. Discerning the highest level of spinal cord injury on each person was important finding the injury’s specific neurological impacts down the chain of innervated muscles and organs. Then they took it one more step to differentiate an overactive bladder muscle’s (DOA) dysfunctional performance from its inverse-yet-more-commonly-found bladder muscle dysfunction of detrusor underactivity (DUA).

Dr. Kim and his team found that a third of the study subjects had overactive bladders and within that group most (85 per cent) had their highest level of spinal cord injury at or above the 2nd lumbar spine level. The remaining two-thirds of the study subjects had underactive bladders and most (91 per cent) had their highest level of spinal cord injury at or below the 3rd lumbar spine level. Another interesting finding on subjects with overactive bladders was they often had a higher injury at the lowest section of the spinal cord (conus medullaris) a along with the cauda equine injury.