"膝腱-脊髓-膀胱"反射弧重建膀胱功能的解剖与临床

目的：探索反射弧重建膀胱功能的应用解剖和临床疗效。方法：在20具尸体标本上观察与膝腿反射有关的解剖，并应用于3例患者，随访膀胱尿道功能。结果：L3脊神经根中的大部分神经纤维贡献给股神经，S2-4前根与L2-4前根相互间均有重叠，L3-S3前根交叉吻接后2年，刺激膝腿可引发3膀胱内压升高并在膀胱充盈时引起排尿。结论：“膝腱-脊髓-膀胱”反射弧重建膀胱功能时宜选用L3-S3前根交叉吻接。反射弧对恢复SCI患者膀胱功能有一定的作用并仍需进一步研究完善。     

"膝腱-脊髓-膀胱"反射弧的形态学观察

目的 :观察组成“膝腱 脊髓 膀胱”反射弧的神经细胞 ,从形态学上寻找反射弧重建膀胱功能的证据。方法 :5只犬复制成L5 S2前根交叉吻合动物模型后 ,辣根过氧化物酶逆向追踪显示膀胱新支配神经的脊髓中枢 ,并进行吻合口再生神经纤维数量的计算机图像分析。结果 :辣根过氧化物酶标记阳性细胞出现在L5前角 ,以α运动神经元为主 ;吻合口可见较多的神经纤维通过。结论 :形态学上证实“膝腱 脊髓 膀胱”反射弧可以通过L5 S2前根交叉吻合得以建立 ,并且再生的神经纤维数量上达到重建膀胱功能的要求     

不同动力神经根在膀胱功能重建时作用的比较

目的比较L5与S2前根作为动力神经根,对恢复膀胱的神经支配功能和重建排尿功能的作用。方法家犬5只,实验侧行L5-S2前根硬膜外交叉吻接,对照侧行S2-S2前根硬膜外自身吻接,术后1年分别电刺激实验侧和对照侧吻接口的中枢端,记录膀胱压和尿道压的变化。结果L5与S2前根都与膀胱逼尿肌和括约肌建立了神经联系。电刺激测压示:膀胱压实验侧(5.0±2.1)kPa与对照侧(4.6±1.8)kPa相比,差异无显著性意义(P=0.17);尿道压实验侧(4.2±1.7)kPa与对照侧(4.4±1.6)kPa相比,差异也无显著性意义(P=0.31)。结论脊髓损伤后膀胱因失神经支配而发生排尿功能障碍时,应用躯体运动性的L5前根与内脏副交感性的S2前根作为动力神经根来恢复膀胱神经的再支配和膀胱功能重建时,两者作用无明显区别。     

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。     

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。     

膀胱人工反射弧的建立

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前根在硬膜囊内５地显微吻合,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     

人工膀胱反射弧重建治疗脊髓损伤后弛缓性膀胱

目的：探索利用截瘫平面以上正常的体反射重建膀胱反射弧,恢复脊髓损伤后弛缓性膀胱排尿功能的可行性。方法：将Beagle犬L6前根近端与S2前根远端在硬膜内显微吻合,经一段时间的轴突再生后,建立＂膝腱-脊髓中枢-膀胱＂人工反射弧,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和辣根过氧化物酶（HRP）逆行示踪等检查：对1例L1压缩性骨折伴截瘫患者行右侧T11与S2前根经腓肠神经移植硬膜内吻合术。结果：2只犬在术后8个月时电刺激截瘫前和截瘫后左侧L6后根、神经吻合口近端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,当刺激开始时逼尿肌压力和膀胱内压均迅速上升,而腹内压增加幅度较小,刺激中止后膀胱内压迅速下降;膀胱注射HRP后48h实验侧L6脊髓节段前角中发现HRP标记的大神经元细胞。临床1例患者术后55个月时随访,膀胱充盈后可产生自控性排尿,尿流动力学显示排尿完全是由膀胱逼尿肌的收缩引发。结论：利用截瘫平面以上正常的体反射建立人工反射弧通路是成功和有效的,可恢复脊髓损伤后弛缓性膀胱自控性排尿。     

截瘫后经马尾骶神经根重建自控性膀胱功能

目的 通过对截瘫患马尾骶神经根的桥接来改善膀胱功能,建立起自控性膀胱。方法 将2例截瘫后患行切断15前根,两例行L5-S2前根的桥接。结果 2例患近期表现为膀胱容量增大,顺应性提高,远期有敲击跟腱后引发排尿．最大尿流率11．0mL/s。结论 建立“腱反射—脊髓中枢—膀胱”的人工反射弧途径来达到重建自控性膀胱功能是可行的。     

利用腹壁反射建立人工膀胱反射弧的辣根过氧化物酶逆行示踪研究

目的研究利用腹壁反射可建立“腹壁反射-脊髓中枢-膀胱”这一新的神经传导通路，通过再生到盆神经的躯体运动神经纤维可实现膀胱的神经再支配，探讨通过刺激下腹壁，该人工膀胱反射弧产生控制性排尿的神经形态学基础。方法选用6只SD大鼠，右侧为实验侧，左侧为对照侧，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。神经缝合术后8个月，应用辣根过氧化物酶(peroxidase horseradish，HRP)逆行追踪标记技术，用微量注射器在双侧膀胱壁上各注射30％HRP 5μl，动物存活60h后经升主动脉灌注杀死。切取T11～L1及L4～S4节段脊髓，冰冻切片后利用TMB法进行呈色反应，观察切片内HRP标记细胞形态及分布情况。结果大鼠膀胱平滑肌注射HRP后，实验侧T13脊髓前角及双侧L6～S4节段脊髓中间带外侧核区有HRP标记阳性细胞，而对照侧T13脊髓前角未发现HRP标记细胞。结论腰骶髓截瘫平面以上的躯体运动神经轴突可长人膀胱平滑肌内副交感冲经节细胞，并由此传递躯体反射冲动到膀胱平滑肌。利用“腹壁反射-脊髓中枢-膀胱”这一人工反射弧，对实现SCI患者膀胱控制性排尿功能，有一定临床意义。     

构建SD大鼠“腹壁反射-脊髓中枢-膀胱”人工反射弧的解剖学观察和功能基础的实验研究

目的为构建SD大鼠“腹壁反射-脊髓-膀胱”人工反射弧研究提供解剖和功能依据。方法对10只SD大鼠麻醉后进行T13和S2神经的解剖,同时通过神经电生理对T13和S2神经进行功能鉴定。SD大鼠肋骨左右共13对,其中最靠远侧端的一对浮肋为T13肋,解剖分离T13肋下的T13肋间神经,向椎间孔方向追踪T13脊神经及其前后根。通过刺激下腹壁记录T13神经根的动作电位,同时记录不刺激时T13神经根的白发神经放电作为对照。骶神经左右共4对,手术显微镜下分离S2脊神经前后根。通过刺激S2神经根记录膀胱神经丛动作电位和膀胱平滑肌肌电,同时记录不刺激时S2神经根的自发神经放电作为对照。并将T13前根近端与S2前根远端通过一段尾神经在硬膜囊内行显微缝合,保持T13后根完整,建立“腹壁反射-脊髓-膀胱”人工膀胱反射弧。结果在解剖上,T13前根直径约0．4mm,S2前根直径约0．3mm,两者直径相近,且均位于腹内侧,无脊神经节。在功能上,T13肋间神经主要支配下腹壁的感觉和运动,S2神经是主要支配膀胱的脊神经。通过刺激,两者均产生相似的动作电位波形。可将T13前根近端与S2前根远端通过一段尾神经在硬膜囊内行显微缝合,同时,保持T13后根完整,建立“腹壁反射-脊髓-膀胱”人工反射弧。结论SD大鼠T13和S2神经根的解剖和功能特点是建立“腹壁反射-脊髓-膀胱”人工反射弧的动物实验模型的基础。     

Staggered rhizotomy of anterior and posterior sacral roots for bladder reservoir function in spinal cord injury: a canine experimental study and preliminary clinical report

Objective: To report an experimental study and preliminary clinical results of staggered anterior and posterior sacral rhizotomy for restoring function of the bladder and preventing reflex incontinence in supra‐conal spinal cord injury (SCI). Methods: Ten T10 spinal cord transected mongrel dogs were divided into three groups. In group 1 (n= 2), laminectomy only was performed (control). In group 2 (n= 4), all L7‐S3 posterior roots were microsurgically cut (complete deafferentation). And in group 3 (n= 4), the L7, S1, S3 posterior roots and S2 anterior root were cut (staggered deafferentation and deefferentation). Intraoperative electrical stimulation and postoperative cystometrography (CMG) were carried out. In the clinic, three patients with spastic bladder caused by a supra conal complete SCI underwent staggered rhizotomy and were followed up for 6 years. Results: In the canine experimental study, resection of the S2 anterior root combined with L7, S1 and S3 posterior rhizotomy, stimulating the S2 posterior root (four dogs) resulted in a minimal rise in pressure in the bladder and urethra, which was only about 10% of that obtained by stimulating the S2 proximal posterior root while its anterior counterpart was intact (eight dogs, Student's t‐test, P < 0.01). The CMG study showed that groups 2 and 3 had similar volume/pressure curves; in both groups the tendency was to develop flaccid bladders. In the clinic, three cases underwent staggered rhizotomy of the anterior and posterior roots in S3 and S4. Good bladder reservoir and compliance was achieved over six years of follow‐up. Conclusion: Staggered rhizotomy of the anterior and posterior sacral roots at different spinal cord levels has the same denervation effect as a complete posterior rhizotomy, and good bladder reservoir function can be achieved by this procedure.     

选择性骶神经前后根组合切断恢复脊髓损伤后膀胱功能的实验研究

目的：探讨脊髓损伤后膀胱完全性去神经传入手术的替代方法。方法：健康杂种犬16只经T10平面截瘫后,按L7－S3神经根切断程度的不同,从完全保留到完全切断分成六组,比较术中神经根（总根和后根）电刺激时的膀胱尿道压力变化和术后膀胱压力容积曲线（CMG）变化。结果 （1）电刺激研究：犬磅胱的神经支配以S2为主,S1次之,尿道的神经支配以S1为主,S2次之,在保留S1或S2前后根完整的情况下,刺激同平面S1或S2的总根或后根,膀胱尿道的压力反应相同,切断S1或S2前根,刺激同平面的S1或S2后根,膀胱尿道的压力反应显著降低。（2）CMG研究：保留同一平面S1或S2前后根的完整,其CMG曲线与完全不切断的对照组相似,形成痉挛性膀胱,不保留同一平面前后根的完整,即切断S1或S2前根,其CMG曲线与切断全部后根的对照组相似,形成驰缓性膀胱,结论 不同平面的骶神经前后根组合切断,能获得与完全性后根切断相同的膀胱去神经效果。     

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     

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。     

腰骶神经吻合对自主性神经原性膀胱排尿功能影响的实验研究

目的:探讨通过腰骶神经吻合恢复或改善神经原性膀胱排尿功能的可行性.方法:10只家犬手术前先行尿流动力(包括膀胱容量、压力、顺应性)及肛门括约肌肌电图(EMG)测定,作为对照组数据.检测完后处死2只.取其S1、S2神经根,共8根作为对照组,行HE染色观察有髓和无髓神经纤维数量.其余8只犬为实验组,将L4与S1、L5与S2神经根分别端端吻合.术后4个月行尿流动力学测定,术后7个月再次行尿流动力学测定后处死动物,取L4、L5和S1、S2神经根吻合口段和骶神经干段行HE染色,观察有髓和无髓神经纤维数量.结果:术后4个月,实验组犬膀胱容量、顺应性和对照组比较明显增加(P<0.05);膀胱压力、肛门括约肌EMG的电压明显降低(P<0.05).术后7个月,实验组犬膀胱压力和肛门括约肌EMG的电压和对照组比较无明显降低(P>0.05);而膀胱容量和顺应性明显增加(P相似文献   

Reconstructed Bladder Innervation Below the Level of Spinal Cord Injury: The Knee-Tendon to Bladder Artificial Reflex Arc

Background/Objective: To study the effectiveness of knee-tendon to bladder artificial reflex arc in dogs.

Methods: In 6 beagles, the proximal end of the right L5 anterior motor root and the distal end of the right S2 anterior root were anastomosed to build a knee-tendon to bladder reflex, whereas the right L5 posterior sensory root was kept intact. Action potential (AP) curves and electromyograms (EMGs) of the detrusor muscle, the intravesical pressure, horseradish peroxidase (HRP)-labeled neurons, and the passing rates of myelinic nerve fibers were calculated to evaluate its feasibility.

Results: AP curves and EMG detected in all 6 dogs were similar to those of the control. Six and 18 months after surgery, the means for bladder contraction induced by percussion of the right knee-tendon were 38 ± 27% and 62 ± 5% that of the normal control, respectively. The mean duration times induced by percussion of the right knee-tendon at 6 and 18 months after surgery were 51 ± 37% and 84 ± 12% that of the normal control, respectively. HRP retrograde tracing and neurohistologic observation indicated the feasibility of the artificial reflex arc.

Conclusions: Our data showed the effectiveness of bladder innervation below the level of spinal cord injury producing urination by knee-tendon to bladder reflex contractions, and therefore, might provide a new clinical approach for restoring bladder function in individuals with paraplegia.     

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.     

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.     

Selective activation of the sacral anterior roots for induction of bladder voiding

AIM: We investigated the efficacy of selective activation of the smaller diameter axons in the sacral anterior roots for electrically induced bladder voiding. MATERIALS AND METHODS: Acute experiments were conducted in five adult dogs. The anterior sacral roots S2 and S3 were implanted bilaterally with tripolar electrodes. Pressures were recorded from the bladder and from the proximal urethra and the external urethral sphincter. A detector and flow meter monitored fluid flow. A complete sacral dorsal rhizotomy was carried out. The effects of two types of pulse trains at 20 Hz were compared; quasitrapezoidal pulses (500 microsec with 500 microsec exponential decay) and interrupted rectangular (100 microsec, 2 sec on/2 sec off). Before rhizotomy, rectangular pulse trains (100 microsec) to activate all fibers were also applied. The experimental design was block randomized before and after rhizotomy. RESULTS: Quasitrapezoidal pulses showed block of sphincter activation with average minimum current for maximum suppression of 1.37 mA. All pulse types evoked average bladder pressures above the basal sphincter closure pressure. The pressure patterns in the proximal urethra closely followed the bladder pressures. Before dorsal rhizotomy, stimulation evoked a superadded increase in sphincter pressures with slow rise time. After rhizotomy, the sphincter pressure patterns followed the bladder pressures during selective activation and voiding occurred during stimulation with quasitrapezoidal trains and in between bursts with interrupted rectangular stimulation. CONCLUSIONS: Selective activation of sacral ventral roots combined with dorsal rhizotomy may provide a viable means of low-pressure continuous voiding in neurological impairment.