膀胱人工反射弧的建立

Establishment of Artificial Bladder Reflex Arc after Spinal Cord Injury

目的 :通过建立家犬人工膀胱反射弧 ,以恢复脊髓损伤后的膀胱功能。它包含一个体反射弧并将体反射运动冲动经异体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—膀胱这一新的人工反射通路 ,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期功能观察。结果 :T10 椎管平面截瘫前后 ,单相方波 ( 115mV ,1.0ms)刺激右L5后根 ,所有 6犬均可在吻合口远端记录到动作电位 ,其形态和波幅与对照组相似 ;4犬术后 6个月截瘫 48h后 ,串刺激 ( 10 0 0mV ,10Hz ,2s)右L5后根 ,经新建的反射弧引出的膀胱收缩平均可达正常对照组的 65 % ,敲击右侧膝腱引出的膀胱收缩平均达正常的 5 1% ;2犬术后 18个月 ,相同电流刺激引出的膀胱收缩平均达正常的 84% ,敲击膝腱平均达 62 % ;电刺激 ( 3 .8mA ,1.0Hz)右L5后根和右股神经 ,2犬匀可记录到膀胱逼尿肌肌电图 ,其形态和波幅与对照组相似。结论 :体神经的运动传出支通过轴突再生能够长入自主神经的副交感性纤维 ,并具有良好的传导运动兴奋的功能 ;利用截瘫平面以下健存的体反射 ,通过硬膜囊?

Objective: To establish an artificial 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 initiate autonomic bladder detrusor contraction. Methods: This is achieved by intradural microanastomosis of the right L 5 ventral root to S 2 ventral root, while leaving the right L 5 dorsal root intact. After axonal regeneration, the pateller ligament spinal cord center bladder new artificial bladder reflex pathway was extablished, and micturition was induced by knocking the pateller ligament. The early and final function of the reflex arc was observed by electrophysiological experiments, bladder pressure tests and detrusor electromyograms(EMG) at 6 months and 18 months postoperation. Results: Single stimuli(115mV, 1.0ms) 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. In 4 canines 6 months postoperation and 48 hours after spinal cord was transected, bladder contraction was very quickly initiated by tranis of stimuli(1000mV,10Hz,2s) of the right L 5 dorsal root and bladder pressures increased rapidly to average 65% of normal compared to controls. Bladder contraction induced by knocking the right pateller ligament increased to average 51% of controls through the new reflex arc. In 2 canines 18 months postoperation, bladder pressures increased by the same stimuli to average 84% of controls and to average 62% of controls by knocking the pateller ligament. Stimuli(3.8mA,1.0Hz) of the right L 5 dorsal root and femoral nerve resulted in EMG recorded from the dertrusor in 2 canines 18 months postoperation.Conclusion: The somatic motor axons can regenerate 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.