脊髓损伤后膀胱人工反射弧建立的实验研究

目的 通过建立家犬人工膀胱反射孤，以恢复脊髓损伤后的膀胱功能。它包含一个体反射孤，并将体反射运动冲动经异化的运动传出支传入膀胱，引起膀胱的自主性收缩．方法 将右Ｌ５前根近端与右Ｓ２前根远端在硬膜囊内行显微吻合，保持Ｌ５后根完整，经轴突再生后，建立膝腱－脊髓中枢－膀胱这一新人工反射通路，通过刺激右侧膝腱激发排尿。神经根吻合术后６个月和１８个月，分别进行神经电生理、膀胱测压、膀胱逼尿肌肌电图等早期和远

EXPERIMENTAL STUDY ON ESTABLISHMENT OF ARTIFICIAL BLADDER REFLEX ARC AFTER SPINAL CORD INJURY

Objective\ To establish an artificial bladder reflex arc in canines to reinnervate the neuropathic bladder and restore bladder function after spinal cord injury.It involves a somatic reflex arc with a modified efferent branch which passes the somatic motor impulses to the bladder and initiates autonomic bladder detrusor contraction.Methods\ Intradural microanastomosis of the right L 5 ventral root to S 2 ventral root was performed to maintain the right L 5 dorsal root intact.After axonal regeneration,the new patellar ligament spinal cord center bladder artificial bladder reflex pathway was established,and micturition was induced by knocking the patellar ligament.The early and final function of the reflex arc was observed by electrophysiological examinations, bladder pressure tests and detrusor electromyograms(EMG)at 6 months and 18 months postoperatively.Results\ Single stimuli (115 mV, 1.0 ms)of the right L 5 dorsal root resulted in evoked potentials recorded from the right S 2 ventral root distal to the anastomosized site before and after the spinal cord was transected horizontally at the T 10 segment level in all 6 canines.Bladder contraction was very quickly initiated by trains of stimuli(1 000 mV,10 Hz,2 s)of the right L 5 dorsal root and bladder pressures increased rapidly to 65% of normal, and bladder contraction induced by knocking the right patellar ligament was increased to 51% of normal through the new reflex arc in 4 canines after 6 months of operation.Bladder pressures were increased by the same stimuli to average 84% of normal and to 62% of normal by knocking the patellar ligament in 2 canines after 18 months of operation. Stimuli(3.8 mA,1.0 Hz) of the right L 5 dorsal root and femoral nerve resulted in EMG similar to normal EMG could be recorded from the detrusor in 2 canines after 18 months postoperatively.Conclusion\ The somatic motor axons can be regenerated into the parasympathetic endoneurial tubes of autonomic nerve.Using the survived somatic reflex under the horizon of spinal cord injury to reconstruct the bladder autonomic reflex arc by intradural microanastomosis of ventral root is practical in the canine model and may have a potential of clinical application.