Establishing an animal model of DU by conus medullaris transection offers an excellent opportunity for starting the pathophysiology of detrusor underactivity. Our protocol is the first to use conus medullaris transection to induce detrusor underactivity in an animal model. To perform a conus medullaris transection, First, make a three centimeter median skin incision on the back of the animal.
Use surgical scissors to deepen the incision through the subcutaneous tissues and excise the muscles attached to the spine To expose the 13th rib. And carefully resect the muscles attached to the spine to expose the vertebral column. Resect the supraspinous, and interspinous ligaments.
And use surgical scissors and forceps to expose the spine at L4 to L5.Use Kelly forceps to carefully remove the L4 to L5 vertebral spinous process and parts of the transverse process to expose the spinal cord. And completely expose the conus medullaris at L4 to L5.Use iridectomy scissors to completely transect the conus medullaris. And insert tissue packing to block the recovery of the spinal cord.
Then use a 4-0 non-absorbable suture to close the overlying muscle and skin. And place the rat in a 37 degree Celsius incubator for the first hour post-procedure, with monitoring until the animal is sternal or actively moving. Urine retention is observed immediately after surgery, with the peak point of volume appearing on the second day post-operation, and gradually decreasing for about 10 days.
Ten days after surgery, the retention volume reaches a steady level. Urodynamic testing reveals that the maximum cytometric capacity and bladder compliance are significantly higher in the test group, while the detrusor opening pressure in the test group decreases significantly compared to the control group. Correctly identifying the 13th rib is a key step for successful identification of the L4 to L5 vertebra.
