Experimental Studies Of Bladder Controller To Restore Micturition And Defecation Function In Spinal Cord Injuries

【Objective】 To evaluate the results of TC-2000 bladder controller to restore micturition and defecation function in paraplegic dogs. Long-term results of the first case patient with bladder controller implantation in China was followed and the capability of control part of TC-2000 bladder controller was tested in this patient.【Methods】4 dogs were included in this study after their spinal cord were transected above the cone.Electrodes were implanted around S2 bilaterally and connected to subcutaneous recievers for external activation. Microsurgical techniques were employed to perform dorsal rhizotomy of S1-3 intradurally. The dogs were　stimulated daily. Micturition and defecation was observed.Urodynamic testing, rectal pressure recording and vesicography were performed S2 nerve roots bilaterally were cut for histological and ultrastructure examination to observe whether the stimulated nerve roots were damaged or not after a cumulated time of 150h each. Paraplegic dogs were stimulated continuously before the end of the experiment. Long-term results of the first case patient with bladder controller implantation in China was followed and the capability of control part of TC-2000 bladder controller was tested in this patient under her permission. 【Results】 All the dogs acquired mictuation under control of electric stimulation, urine volume 80-140ml per time. The mode of mictuation was post-stimulus voiding: Micturition was intermittent and occurred during the gaps between the bursts of stimulation. The peak was usually attainted between the third and the fourth bursts. The stream of urine during each gap rose smoothly to a maximam and then decreased smoothly. This indicated detrusor-spincter synergetic. Vesicography found bladder were filled well and bladder neck was open in the mictuation course of electric stimulation. Residual urine volume was 15-20 ml. Urodynamic testing found bladder pressure and intraurethral pressure increased simultaneously and intraurethral pressure was bigger, micturition didn't occur at this time. At the gaps between two bursts , intraurethral pressure decreased to base line rapidly and bladder pressure decreased slowly. Micturition was occurring when bladder pressure was bigger than intraurethral pressure. All the dogs acquired defecation under control of electric stimulation, 1 to 3 times a day. The defecation and rectal pressure elevation often happened in the course of electric stimulation. Histological examination indicated the structure of ventral roots of sacral nerve hadn't apparent degenertion after a cumulated stimulation time of 162h. The nerve fibre of dorsal roots was degeneration and nerve was embedded in fibre connective tissue. The ultrastructure of axon was normal, a little segment of the myelin sheath was loose, rough endosarc net and collagen secreted bloomly, this indicated fibroblast proliferation. The patient of bladder controller implantation was followed up to date. Micturition can be contolled under electric stimulation by herself and absolute continent be achived. Renal function of her is normal. The capability of control part of TC-2000 bladder controller is good and the patient can also have a normal micturition under the control of TC-2000 bladder controller. 【Conclusion】 TC-2000 Bladder controller together with a sacral deafferentation procedure can restore micturition and defecation function of paraplegic dogs. The capability of control part is same to the import apparatus. It will be used in clinic widely.