大鼠脊髓损伤后膀胱生理反射弧重建的实验研究

目的 探讨利用截瘫平面以上健存的神经根,与硬脊膜内骶神经前后根分别吻合,建立人工膀胱反射通路,重建膀胱生理反射弧的有效性.方法 取3月龄雄性SD大鼠20只,体重250～300 g;右侧为实验侧,左侧为对照侧.将大鼠右侧L5前根近端与右侧S2前根远端,L5后根近端与S2后根远端在硬脊膜囊内分别行显微缝合,同时修复重建膀胱的感觉与运动功能,建立人工膀胱生理反射弧.左侧不作任何处理.于术后5个月,在破坏L6～S4节段脊髓制备完全性截瘫前后,分别进行电生理检查及膀胱内压测定.结果 18只大鼠存活至术后5个月,9只大鼠成功分离出吻合的神经根,获得实验结果.实验侧截瘫前后,单相方波(3mA、0.3ms)刺激S2后根吻合口远端,均可记录到膀胱神经丛动作电位,波幅分别为(0.10±0.02)mV和(0.11±0.03)mV,差异无统计学意义(P>0.05);串刺激(3mA、20Hz、5 s)S2后根,均可记录到膀胱平滑肌复合肌肉动作电位,其波幅分别为(0.11±0.02)mV和(0.11±0.03)mV,差异无统计学意义(P>0.05).刺激S2后根吻合口远端,经新建的人工膀胱反射弧引出的膀胱内压分别为(6.55±1.33)cmH2O和(6.11±2.01)cmH2O,差异无统计学意义(P>0.05).对照侧截瘫前刺激S2后根,引出的膀胱神经丛动作电位波幅为(0.144±0.02)mV,膀胱平滑肌复合肌肉动作电位波幅为(0.17±0.02)mV,膀胱内压为(10.77±1.78)cmH2O,均大于实验侧截瘫前后(P<0.01).而电刺激对照侧截瘫后S2后根,不能引出膀胱神经丛动作电位、平滑肌复合肌肉动作电位,膀胱内压无变化.结论 利用截瘫平面以上健存的神经根,通过与硬脊膜内骶神经前后根分别吻合,可建立完整的人工膀胱反射弧,有望实现截瘫患者自主性排尿.     

具有感觉传入通路的膀胱反射弧治疗脊髓损伤后弛缓性膀胱的实验研究

 目的 用SD大鼠构建具有感觉传入通路的膀胱反射弧,探讨其用于治疗脊髓损伤后弛缓性膀胱的有效性。方法 SD雄性大鼠24只,右侧为实验侧,先行L5前根近断端与S2前根远断端吻合,再将L5脊神经节周围突支近断端与S2后根远断端行端端吻合。左侧不做处理,为对照侧。术后3个月,破坏L6~S4节段脊髓造成弛缓性膀胱,于建模前后通过一般观察、神经电生理检测、神经示踪等方法观察反射弧构建情况。结果 21只大鼠存活至术后3个月,7只成功分离出吻合的脊神经。电刺激实验侧S2后根吻合口远端,均能检测到膀胱神经丛复合动作电位、膀胱平滑肌复合肌肉动作电位,截瘫前后动作电位差异无统计学意义;电刺激对照侧S2后根,在截瘫后未能检测到动作电位。实验侧膀胱神经丛复合动作电位和膀胱平滑肌复合肌肉动作电位平均波幅为截瘫前对照侧的71.9%和82.4%。神经示踪结果显示实验侧L5脊髓前、后角均可见青蓝色阳性反应颗粒。结论 构建具有感觉传入通路的膀胱反射弧,可使其运动、感觉神经通过轴突再生长入副交感神经纤维,并与脊髓前、后角重建轴突联系,轴浆运输功能得到重建,可用于弛缓性膀胱的治疗。     

Reconstruction of atonic bladder innervation after spinal cord injury: A bladder reflex arc with afferent and efferent pathways

Abstract

Background

Establishing bladder reflex arcs only with the efferent pathway to induce micturition after spinal cord injury (SCI) has been successful. However, the absence of sensory function and micturition desires can lead to serious complications.

Objectives

To reconstruct a bladder reflex arc with both afferent and efferent pathways to achieve atonic bladder innervation after SCI.

Methods

A reflex arc was established by microanastomosis of the S2 dorsal root to the peripheral process of the L5 dorsal ganglion and the L5 ventral root to the S2 ventral root. The functions of the reflex arc were evaluated using electrophysiology, wheat germ agglutinin–horseradish peroxidase (WGA–HRP) tracing, and calcitonin gene-related peptide (CGRP) immunocytochemistry analysis. Hind-paw motion was evaluated by CatWalk gait.

Results

Compound action potentials and compound muscle action potentials were recorded at the right L5 dorsal root following electrical stimulation of right S2 dorsal root. Similar to the control side, these were not significantly different before or after the spinal cord destruction between L6 and S4. WGA–HRP tracing and CGRP immunocytochemistry showed that construction of the afferent and efferent pathways of the bladder reflex arc encouraged axonal regeneration of motor and sensory nerves, which then made contact with the anterior and posterior horns of the spinal cord, ultimately reestablishing axoplasmic transportation. Gait analysis showed that at 3 months following the operation, only the regularity index was significantly different as compared with 1 day before the operation, other parameters showing no difference.

Conclusion

Bladder reflex arc with the afferent and efferent pathways reconstructs the micturition function without great influence on the motion of leg.     

Micturition reflex arc reconstruction including sensory and motor nerves after spinal cord injury: Urodynamic and electrophysiological responses

Abstract

Objective

To evaluate artificial reflex arcs for micturition using urodynamics and electrophysiological recordings.

Design

Sixteen beagles were equally and randomly divided into two groups.

Methods

In group A, anastomosis of the proximal end of the left L7 ventral root (VR) and distal end of the left S2 VR was performed, as well as anastomosis of the L7 dorsal root (DR) and S2 DR to reconstruct the sensory and the motor function of the bladder. In group B the proximal end of the left L7 VR and the distal end of the left S2 VR were anastomosed, while the left L7 DR was kept intact to reconstruct the motor function of the bladder. Outcome measures included electrophysiological testing and the urodynamic measures. In addition, we also monitored urinary infection rates.

Results

Stimulation to the left S2 DR in groups A and B both elevated the bladder pressure before and after the spinal lower motor neuron lesion. Single stimulation of the two groups both elicited evoked action potentials. Urinary infections occurred in group A (three occurrences) and in group B (eight occurrences) during the 3 months after the spinal lower motor neuron lesion.

Conclusion

Data showed that both reconstructive methods could induce bladder micturition and evoked action potentials. However, in group A the micturition response was better and the urinary infection rates were lower after the spinal lower motor neuron lesion. Thus, the artificial physiological reflex arc reconstruction method used in group A, with sensory input above the lesion, might provide a better alternative in clinical practice.     

Root reconstruction for bladder reinnervation: an experimental study in rats

Nerve transfer (or nerve crossover) is a well established technique for achieving reinnervation of a valuable sensory or motor territory by reconnection using a functional nerve of lesser value. Patients with lower spinal cord lesions causing neurogenic bladder dysfunction could theoretically benefit from such an approach for return of useful micturition. Based on the known anatomical details of the spinal nerve, a new reconstructive method was created to provide intradural ventral root transfer for pure motor-to-motor reinnervation and extradural postganglionic spinal nerve transfer for pure sensory-to-sensory reinnervation. Experimental studies in rats were performed, demonstrating the feasibility of this approach. A modified method is further suggested that would use nerve grafts for extradural approaches to pure motor and sensory transfers, without the need for extensive laminectomy and dura opening. This proposed approach is anticipated to minimize the associated morbidity and mortality with such spinal nerve reconstruction.     

人工膀胱反射弧的实验与临床研究

目的 建立人工膀胱反射弧,以恢复脊髓损伤后的膀胱功能,它将体反射运动是化的运动同支传入膀胱,引起膀胱的自主性收缩。方法 将犬右Ｌ５前根近端与右Ｓ２前根远端在硬膜内吻合,经轴突再生后,建立膝腱－脊髓中枢－膀胱人工反射通路。进行神经电生理、膀胱测压、膀胱逼尿肌 图等早期和无期功能观察。临床１例Ｔ２、３完全性截竣患者,硬膜内行双侧Ｌ５与Ｓ２前根的吻合。结果 单相方波（１１５ｍＶ,１．０ｍｓ）刺激右Ｌ５后     

Micturition reflex arc reconstruction including sensory and motor nerves after spinal cord injury: urodynamic and electrophysiological responses

Objective

To evaluate artificial reflex arcs for micturition using urodynamics and electrophysiological recordings.

Design

Sixteen beagles were equally and randomly divided into two groups.

Methods

In group A, anastomosis of the proximal end of the left L7 ventral root (VR) and distal end of the left S2 VR was performed, as well as anastomosis of the L7 dorsal root (DR) and S2 DR to reconstruct the sensory and the motor function of the bladder. In group B the proximal end of the left L7 VR and the distal end of the left S2 VR were anastomosed, while the left L7 DR was kept intact to reconstruct the motor function of the bladder. Outcome measures included electrophysiological testing and the urodynamic measures. In addition, we also monitored urinary infection rates.

Results

Stimulation to the left S2 DR in groups A and B both elevated the bladder pressure before and after the spinal lower motor neuron lesion. Single stimulation of the two groups both elicited evoked action potentials. Urinary infections occurred in group A (three occurrences) and in group B (eight occurrences) during the 3 months after the spinal lower motor neuron lesion.

Conclusion

Data showed that both reconstructive methods could induce bladder micturition and evoked action potentials. However, in group A the micturition response was better and the urinary infection rates were lower after the spinal lower motor neuron lesion. Thus, the artificial physiological reflex arc reconstruction method used in group A, with sensory input above the lesion, might provide a better alternative in clinical practice.     

利用腹壁反射重建膀胱反射弧的远期功能性研究

目的：利用截瘫平面以上的腹壁反射通路建立SD大鼠的人工膀胱反射弧,以恢复脊髓损伤（SCI）后可控制性膀胱排尿功能。它包含了一个皮肤反射弧（下腹壁反射弧）,并将皮肤反射的运动冲动传入膀胱,引起膀胱的自主性收缩。方法：将SD大鼠右侧T13前根近端与右侧S2前根远端通过一段自体移植神经在硬膜囊内行显微缝合,保持T13后根完整,经一段时间轴突再生后,建立“腹壁反射－脊髓中枢－膀胱”这一新的人工膀胱反射弧。通过刺激右侧下腹壁反射激发截瘫动物排尿。神经缝合术后8个月,在破坏L5－S4脊髓节段前后,分别进行神经电生理、膀胱测压和神经药理学实验等远期功能观察。结果：在破坏L5－S4脊髓节段造成截瘫前后,单相方波（3mA,0.3ms）刺激实验测T13后根,12只SD大鼠的实验侧膀胱神经丛可记录到动作电位,其形态和波幅与对照组相似;串刺激（3mA,20Hz,5s）实验侧T13后根,经新建的膀胱人工反射弧引出膀胱平均内压达对照侧的76％,膀胱平滑肌复合肌肉运作电位平均最大波幅达对照侧81％,波形与对照组相似。在膀胱平滑肌内注射阿托品（0．05mg/kg）或三甲噻酚（5mg/kg）可抑制通过该人工反射弧激发的膀胱平滑肌收缩功能,而膀胱平滑肌肉注射维库溴铵（4mg/kg）对膀胱平滑肌收缩功能无影响。结论：体神经的运动传出支经自体神经移植,其轴突能够再生长入自主神经的副交感神经纤维,并具有良好的传导运动兴奋的功能,新的神经传导通路含有N1和M型受体,冲动传递的神经递质为乙酰胆碱;利用截瘫平面以上的体反射,通过硬膜囊内神经根自体神经移植缝合的方法,可建立新的人工膀胱反射弧,实现截瘫患者可控制性排尿。     

Reconstruction of reflex pathways to the atonic bladder after conus medullaris injury: preliminary clinical results

Neurogenic bladder dysfunction following spinal cord injury is a major medical and social problem for which there is no ideal treatment strategy. In this study, spinal root anastomoses were performed in 10 paraplegic patients with traumatic lesions of the conus medullaris, in an attempt to reinnervate the paralyzed bladder. For the operation, the functional T11 ventral root (VR) above the lesion was transected and anastomosed to the S2 ventral roots unilaterally through a nerve graft. The T11 dorsal root was left intact as the trigger for micturition after axonal regeneration. All patients underwent urodynamic evaluation before surgery and at follow-up. The mean follow-up duration was 2 years. Of the 10 patients, 7 (70%) regained satisfactory bladder control within 18-24 months after VR microanastomosis. In these seven patients, the average bladder capacity decreased from 508 +/- 83 (mean +/- SD) to 370 +/- 59 ml, residual urine decreased from 477 +/- 98 to 35 +/- 11 ml, and urinary infections were not observed. Patients with impaired renal function experienced a full recovery. Three patients failed to show any improvement after the operation. These results suggest that a restitutive process occurs in the bladder following reinnervation from new T11 VR connections to the bladder nerves. Spinal cord lesions that may benefit from such a nerve crossover surgery are those located at the conus, whereby a functional suprasacral nerve can be connected to the sacral roots to bypass the injury in an attempt to restore central connections to the bladder.     

人工体神经-内脏神经反射弧传出通路神经追踪研究

目的：研究大鼠人工体神经－内脏神经反射弧传出神经元胞体及其纤维末梢的分布。方法：将建立了人工体神经－内脏神经反射弧的11只模型大鼠随机分为3组（n＝4、4、3），分别用荧光金（FG）结合快蓝（FB）、辣根过氧化物酶（HRP），麦芽凝集素－辣根过氧化物酶（WGA－HRP）逆行顺行神经追踪。结果：左侧盆神经节（MPG）注射FG，尿道外括约肌（EUS）左侧注射FB后，可见FG、FB单标神经元及FG和FB双标神经元主要分布于脊髓L3尾部至L5头侧左侧前角。膀胱肌层注射HRP后，在左侧MPG可见HRP阳性神经元，WGA－HRP注射入脊髓L4左侧前角顺行追踪显示，左侧MPG4和EUS内有HRP阳性神经末梢。结论：躯体运动神经（L4VR）可以再生替代内脏传出和躯体运动混合神经，再生的神经纤维部分直接支配EUS，部分终止于MPG，在MPG内换元，由节后神经元支配膀胱，躯体运动神经元同时支配MPG和EUS可能是人工体神经－内脏神经反射弧控制排尿的主要神经解剖学基础。     

体神经-内脏神经吻合术修复脊髓损伤大鼠排便功能及机制研究

目的 应用肛肠动力学和神经形态学技术观察体神经-内脏神经吻合术后,在脊髓损伤(SCI)大鼠的所形成的再生异类神经通路对肛管直肠的支配功能及直肠平滑肌-肛门外括约肌的协同,并探讨其机制.方法 在成年雄性SD大鼠(250～300 g)的L4～L6椎管内,将左侧L4前根(L4VR)与左侧L6前根(L6VR)分别离断后,通过端端显微吻合技术,人工建立L4VR～L6VR异类神经前根.保留L4背根(L4DR)来传导传人信号.术后12周行T9～T10椎间脊髓横断,8周后将12只模型大鼠随机分为2组(n1=8,n2=4).取1组8只模型大鼠进行肛肠动力学研究;取2组4只模型大鼠进行神经形态学研究.结果 (1)电刺激吻合口近端神经及左侧坐骨神经,在引起直肠压力升高的同时出现肛门外括约肌的肌电活动大幅减弱;而电刺激自身对照侧L6VR,在引起直肠压力升高的同时出现肛门外括约肌肌电活动明显增强.(2)主要在模型鼠脊髓L4节段左侧前角(脊髓L3尾部至L5头侧均有阳性神经元)可见FG与TMR双标神经元及FG、四甲基罗丹明单标神经元;正常鼠神经逆行追踪未见双标神经元.结论 体神经-内脏神经吻合术可有效修复脊髓损伤大鼠肛管直肠功能,改善脊髓损伤后的直肠平滑肌-肛门括约肌协同失调.在模型大鼠脊髓L4节段新出现的双标神经元同时支配着盆神经节和肛门外括约肌,这可能是体神经-内脏神经吻合术修复模型大鼠排便功能主要神经解剖学基础.     

Change of vanilloid receptor 1 following neuromodulation in rats with spinal cord injury

BACKGROUND: Neuromodulation has been used to treat voiding dysfunction caused by spinal cord injury (SCI). However, the underlying mechanism of this technique is not well understood. Recently, vanilloid receptor 1 (VR1) has been recognized as a capsaicin receptor and an agent for noxious stimuli. The purposes of this study were to evaluate whether development of bladder hyperreflexia after SCI involves VR1 upregulation and whether VR1 is involved in the process of neuromodulation. MATERIALS AND METHODS: Sprague-Dawley rats (n = 20) were divided into five groups: sham control (n = 4); 3 days after SCI (n = 4); 7 days after SCI (n = 4); 14 days after SCI (n = 4), and 14 days after SCI with neurostimulation (n = 4). Bilateral electrode wires were implanted into S1 dorsal foramina and electrical stimulation was performed 8 h/day for 2 weeks. Spinal segments of L6, S1, and dorsal root ganglia were removed and cut into sections. The intensity of VR1 staining was evaluated by image analysis. RESULTS: VR1-positive staining was confined to the superficial dorsal horn of the spinal cord. The staining was weak in the sham group (1/luminosity: 0.0050 +/- 0.0006), but the staining intensity was significantly increased in three SCI groups (3 days, 7 days, and 14 days) when compared with that in the sham group (P < 0.05). After neuromodulation, the staining intensity was reduced. CONCLUSIONS: VR1 expression in the spinal cord is up-regulated after SCI. Sacral nerve root stimulation can down-regulate the VR1 expression.     

Immunoneutralization of nerve growth factor in lumbosacral spinal cord reduces bladder hyperreflexia in spinal cord injured rats

PURPOSE: We investigated the effects of intrathecal application of nerve growth factor (NGF) antibodies (Ab) on bladder hyperreflexia in chronic spinalized rats. MATERIALS AND METHODS: In adult female rats an intrathecal catheter was implanted at the level of the L6 to S1 spinal cord, followed by complete transection of the Th8 to 9 spinal cord. At 10 days after spinalization the intrathecal catheter was connected to an osmotic pump for continuous delivery of vehicle or NGF Ab (10 microg daily) for 2 weeks. Awake cystometry was then performed. NGF levels in the L5 to S1 dorsal root ganglia, L6 spinal cord and bladder were also measured using enzyme-linked immunosorbent assay. RESULTS: The number of uninhibited bladder contractions per voiding cycle, maximal pressure of uninhibited bladder contraction and maximal voiding pressure were significantly decreased in NGF Ab treated versus vehicle treated spinalized rats. Intercontraction interval, baseline intravesical pressure, pressure threshold for voiding and voiding efficiency were not significantly changed by NGF Ab treatment. NGF levels in the bladder, L6 spinal cord and L5 to S1 dorsal root ganglia of vehicle treated spinalized rats was 1.6 to 4.8 times higher than in spinal cord intact rats. After intrathecal NGF Ab treatment NGF levels were significantly lower in the L6 to S1 dorsal root ganglia (30% to 35%) and L6 spinal cord (53%) but not in the bladder or L5 dorsal root ganglia compared with levels in vehicle treated spinalized rats. CONCLUSIONS: Increased levels of NGF in the bladder, spinal cord and dorsal root ganglia were associated with bladder hyperreflexia after spinal cord injury. Immuno-neutralization of NGF in the spinal cord suppressed NGF levels in the L6 to S1 dorsal root ganglia, which contain bladder afferent neurons, and also suppressed bladder hyperreflexia. Thus, suppression of NGF levels in afferent pathways could be useful for treating bladder hyperreflexia associated with spinal cord injury.     

The feasibility study of extradural nerve anastomosis technique for canine bladder reinnervation after spinal cord injury

Objective: Intradural nerve anastomosis for bladder innervation has been demonstrated to be useful. However, its clinical application remains limited because of the complex surgery, its complications and extensive bony destruction. The purpose of the current study was to demonstrate the feasibility of extradural spinal root anastomosis for bladder innervation in canines.

Methods: Ten beagle dogs were used. The length of the extradural segment of the nerve root, upper nerve root outlet (the point at which it emerges from the spinal dura mater) to S2 (dS2), the S3 (dS3) nerve root outlet distance, and the diameters of the extradural spinal roots were measured. The numbers of nerve fibers from L6 to S3 ventral roots were calculated using immunohistochemical staining.

Results: The extradural spinal roots could be divided into a ventral root (VR) and a dorsal root (DR) before the ganglionic enlargement of the dorsal root, and the extradural motor nerve roots situate ventrally to their corresponding sensory nerve roots. The extradural nerve root lengths of S1 and parts of L7 were longer than the corresponding dS2. The numbers of nerve and motor nerve fibers, and the diameters of extradural nerve roots, were gradually descending from L6 to S3.

Conclusion: The S1 VRs and parts of the L7 VRs can be extradurally anastomosed to the S2 nerves without tension. A nerve graft was needed for extradural anastomosis of L6 VRs and parts of L7 VRs to S2 VRs. This study demonstrated the feasibility of extradural spinal nerve anastomosis for treating neurogenic bladder in canines.     

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     

脊神经前根吻合重建大鼠脊髓损伤后肢体运动功能的实验研究

目的 探讨利用脊髓损伤平面以上正常的脊神经前根与支配股四头肌的优势腰神经前根吻合,重建脊髓损伤大鼠的股四头肌神经通路,恢复脊髓损伤大鼠肢体部分运动功能的效果.方法取4周龄SD大鼠20只,体重120～150 g;左侧为实验侧,右侧为对照侧.将大鼠左侧L1～L5脊神经根分别进行电刺激,根据股四头肌肌电图的检测结果,得出支配股四头肌优势神经根.将左侧L1神经前根与股四头肌优势脊神经前根通过尾神经桥接吻合,重建大鼠股四头肌的神经通路,右侧不作任何处理.术后6个月,在切断左侧L2脊髓水平制备大鼠脊髓损伤模型前后,分别进行电生理检测,饲养4周后进行电刺激大鼠股四头肌运动情况观察,BBB评分及后肢运动观察.结果 16只大鼠存活至术后6个月,10只大鼠成功分离出吻合的神经根,获得实验结果.实验侧截瘫前、后,单相方波(2.5 mA,0.2ms,1 Hz)刺激神经吻合段,均可记录到股四头肌动作电位,波幅分别为(7.63±1.86)mV和(6.00±1.92)mV,差异无统计学意义(P＞0.05);对照侧截瘫后电刺激L3脊神经根,引出的股四头肌动作电位波幅为(15.87±1.16)mV,均大于实验侧截瘫前后股四头肌动作电位波幅(P＜0.05).截瘫后饲养4周,观察大鼠实验侧后肢平地能完成爬行动作,登高时能完成攀高动作;截瘫后1、3、7、14、21、28 d观察后肢运动功能的BBB评分,BBB评分值在伤后1、3、7 d时间点差异均有统计学意义(P＜0.05),在14、21、28 d时间点差异无统计学意义.结论 利用截瘫平面以上健存的脊神经根,通过尾神经桥接吻合股四头肌优势支配神经根,可建立股四头肌新的脊髓旁神经通路,有望实现截瘫患者下肢部分的运动功能.

Abstract：

Objective To establish a paraspinal neural pathway of quadriceps femoris by end-to-end anastomoses between the spinal ventral root after spinal cord injury(SCI) in rats. Methods Twenty-fourweek old SD rats, with the weight of 120 g to 150 g, were included. The left side was the experimental side, while the right side served as a control. Electrostimulating of L1-L5 ventral root was done respectively to decide the predominant nerve of quadriceps femoris. The lumbar 1 ventral root was reveal to little innervation of quadriceps femoris, and the lumbar 3 ventral root was predominant innervation. End-to-end anastomosis between the left L1 and L3 ventral root was done. After axona regeneration, the new paraspinal neural pathway of quadriceps femoris was established. At 6 months postoperatively, the early function of the new pathway was observed by electrophysiological examinations, hindlimb locomotion and BBB (basso, beattie and bresnahan)scale at 1,3,7, 14,21,28 d after SCI. Results Sixteen rats survived for 6 months after operation and only ten rats got good results because of tissue adhesion postoperatively. Single stimuli (2.5 mA,0.2 ms, 1 Hz) of the left anastomoses nerve resulted in action potential recorded from the left quadriceps femoris before and after the spinal cord hemisection horizontally between L2 segmental levels. The amplitudes of the action potentials were (7.63 ± 1.86) mV and (6.00 ± 1.92)mV, respectively, and there was no significant difference (P ＞ 0.05). The left quadriceps femoris contraction was initiated by single stimuli (2.5mA, 0.2 ms, 1 Hz) of the left anastomoses nerve. After paraplegia, when the right L3 ventral root was stimulated, the amplitude of the action potential was (15.87 ± 1.16) mV. Locomotion of the left hindlimb was partially restored after spinal cord hemisection while creeping and climbing. According to BBB scale, there was significant difference at 1, 3, 7 d, and little difference at 14, 21, 28 d after SCI. Conclusion Spinal ventral roots cross-ananstomosis to reconstruct the paraspinal pathway of quadriceps femoris after SCI is efficient reinnervation of hindlamb muscles in a rat model and may have potential in clinical application.     

人工膀胱反射弧的远期功能观察

目的 :建立犬人工膀胱反射通路 ,以恢复脊髓损伤后的膀胱功能 ,观察人工反射弧的远期功能状态。方法 :将右L5前根近端与右S2 前根远端在硬膜囊内吻合 ,经轴突再生后 ,建立膝腱—脊髓中枢—膀胱这一新的人工膀胱反射通路 ,通过刺激膝腱激发排尿。结果 :神经根吻合术后 18个月 ,T10 平面截瘫 48h后 ,通过电刺激传入神经 ,经新建的反射弧引出的膀胱收缩平均可达正常的 84% ,敲击膝腱引出的膀胱收缩平均达正常的 6 2 % ;电刺激右L5后根和右股神经 ,均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 ,通过神经根吻合的方法 ,可建立人工膀胱反射弧 ,实现患者的控制性排尿。     

建立人工膀胱反射弧治疗脊髓损伤后弛缓性膀胱的实验研究

目的探讨利用脊髓损伤平面以上健存的体反射重建人工膀胱反射弧,恢复脊髓损伤(spinalcordinjury,SCI)后膀胱排尿功能。方法1岁龄雄性Beegle犬8只,体重9.5±2.0kg。取后正中切口暴露L4～S3的棘突和椎板,全椎板切除后暴露硬膜和脊神经根,在硬膜外初步分离和确认L6和S2前根。确定犬左侧为实验侧,将左侧L6与S2前根分别在穿神经根管处切断,切开硬膜囊,从硬膜外L6和S2前根追溯硬膜内神经根,在显微镜下将L6和S2前根在硬膜内吻合。经一段时间轴突再生后,建立“膝腱-脊髓中枢-膀胱”人工反射弧。神经缝合术后8个月,在破坏S1～S4脊髓节段前后,分别进行神经电生理、膀胱肌电图及尿流动力学等远期功能观察。结果术后8个月,3只犬死亡,3只犬未能分离出吻合的神经,无实验结果。余2只犬均获得满意结果,定为1号和2号犬,进行观察。刺激(连续刺激强度200μV,刺激间隔为5ms)截瘫前和截瘫后2只犬左侧L6后根、神经吻合口,均可在吻合口远端记录到运动诱发电位,其波形和波幅相似;尿流动力学检查可见,当刺激开始时膀胱内压迅速上升,而腹内压增加幅度较小,刺激中止后膀胱内压迅速下降,证实膀胱内压升高主要是由逼尿肌收缩产生,电刺激左侧L6后根和吻合口膀胱内压升高值均可达到正常的60%左右。结论利用脊髓损伤平面以上健存的体反射重建膀胱反射通路是成功和有效的,体神经的运动支通过轴突再生能够长入自主神经的副交感神经纤维,并具有良好的传导运动兴奋的功能。     

Urinary bladder reinnervation

The ability of mixed spinal nerve roots to regenerate and reinnervate the urinary bladder was examined in young adult female cats. Using microsurgical technique, a unilateral extradural spinal nerve root anastomosis of a lumbar (L7) to a sacral root (S1) either with or without a nerve graft was performed. Remaining ipsilateral sacral roots were transected. The contralateral normal sacral roots remained intact and allowed the animals adequate urination during the period necessary for axonal regeneration. At the time of restudy seven months later, stimulation of the anastomosed nerve root proximal to the anastomosis (isolated from the spinal cord) elicited a bladder contraction. Significant lumbar axonal regeneration was substantiated by compound action potentials recorded across the anastomosis. In addition, redirection of axons from a lumbar to a sacral distribution was demonstrated. The contralateral normal sacral roots provided control cystometric and electrophysiological data against which responses from the previously anastomosed nerve roots were compared. In conclusion, significant bladder reinnervation can occur after an anastomosis of a lumbar and sacral root with or without a nerve graft. This technique, or variations thereof, may have a clinical role in selected patients with neurogenic bladder dysfunction to reinnervate the bladder and restore central control.     

Functional reinnervation of the canine bladder after spinal root transection and immediate somatic nerve transfer

This study was performed to determine whether nerve transfer immediately after spinal root transection would lead to bladder reinnervation in a canine model. In one animal, the left T12 intercostal nerve was mobilized, cut and attached to the severed ends of sacral roots inducing bladder contraction using a graft from the T11 intercostal nerve. On the right side and bilaterally in two other dogs, coccygeal roots innervating tail musculature were cut and attached to the severed bladder sacral roots (coccygeal nerve transfer [CG NT]). In four other dogs, bladder sacral roots were transected in the vertebral column, and the genitofemoral nerve was transferred within the abdomen to the pelvic nerve (genitofemoral nerve transfer [GF NT]). After 14 months for CG NT and 4.5 months for GF NT, electrical stimulation of the pelvic nerve induced bladder pressure and urethral fluid flow on the intercostal nerve transfer side, in each of the five CG NT sites and bilaterally in three of the four GF NT animals. Reinnervation was further shown by retrograde labeling of spinal cord neurons following fluorogold injections into the bladder wall and by histological examination of the root/nerve suture sites. In all CG NT animals, labeled neuronal cell bodies were located in ventral horns in lamina IX of coccygeal cord segments. In the three GF NT animals in which pelvic nerve stimulation induced bladder contraction, abundant labeled cell bodies were observed in lamina IX and lateral zona intermedia of upper lumbar cord. These results clearly demonstrate that bladder reinnervation can be accomplished by immediate nerve transfer of intercostal nerves or coccygeal spinal roots to severed bladder sacral roots, or by transfer of peripheral genitofemoral nerves (L1,2 origin) to pelvic nerves.