硬膜外注射倍他米松-利多卡因混合液对兔神经根炎症及硬膜外粘连的影响

Objective To investigate the effects of epidural administration of a mixture of betamethasone and lidocaine on nerve root inflammation and epidural space adhesion in rabbits. Methods Twenty-four adult male New Zealand white rabbits weighing 2.0-2.1 kg, were randomly divided into 2 groups ( n = 12 each): control group and treatment group. A catheter was inserted into epidural space at L2,3 interspace. Twenty-four hour after epidural catheter placement, talcum powder 0.5 mg/kg was injected into epidural space to make the model of nerve root inflammation and epidural space adhesion. Three days later a mixture of lidocaine 2.5 mg/kg and betamethasone 0.25 mg/kg was injected via the epidural catheter in treatment group, while the equal volume of normal saline was given in control group. At 21 days after administration of lidocaine and betamethasone, the spinal cord was removed, and dura mater and nerve root were checked with naked eye, light microscope and electron microscope.The neutrophil count in the dura mater was determined. Results There was nerve root inflammation and epidural space adhesion in control group. The nerve root inflammation and epidural space adhesion was not observed in treatment group. The neutrophil count was reduced in treatment group (21 ± 12) compared with control group (250 ±43) ( P < 0.01) . Conclusion Epidural administration of a mixture of betamethasone and lidocaine can alleviate nerve root inflammation and epidural space adhesion.     

硬膜外注射倍他米松-利多卡因混合液对兔神经根炎症及硬膜外粘连的影响

Objective To investigate the effects of epidural administration of a mixture of betamethasone and lidocaine on nerve root inflammation and epidural space adhesion in rabbits. Methods Twenty-four adult male New Zealand white rabbits weighing 2.0-2.1 kg, were randomly divided into 2 groups ( n = 12 each): control group and treatment group. A catheter was inserted into epidural space at L2,3 interspace. Twenty-four hour after epidural catheter placement, talcum powder 0.5 mg/kg was injected into epidural space to make the model of nerve root inflammation and epidural space adhesion. Three days later a mixture of lidocaine 2.5 mg/kg and betamethasone 0.25 mg/kg was injected via the epidural catheter in treatment group, while the equal volume of normal saline was given in control group. At 21 days after administration of lidocaine and betamethasone, the spinal cord was removed, and dura mater and nerve root were checked with naked eye, light microscope and electron microscope.The neutrophil count in the dura mater was determined. Results There was nerve root inflammation and epidural space adhesion in control group. The nerve root inflammation and epidural space adhesion was not observed in treatment group. The neutrophil count was reduced in treatment group (21 ± 12) compared with control group (250 ±43) ( P < 0.01) . Conclusion Epidural administration of a mixture of betamethasone and lidocaine can alleviate nerve root inflammation and epidural space adhesion.     

Adenoviral gene transfer in the peripheral nervous system

Background Viral vectors have gained widespread use as vehicles for somatic gene transfer, and the targeted expression of foreign proteins by these vectors offers advantages over the systemic administration of the drugs in some therapeutic situations. Selective virus-mediated gene transfer to the peripheral nervous system (PNS), however, remains to be established. There are no data showing efficiency of protein transduction in the PNS, which consists of a variety of cell types, many of which are postmitotic. Methods We prepared the first-generation replication-deficient recombinant adenovirus vectors engineered to express LacZ. Eight-week-old Wister rats were used in this study. Adenovirus vector (5 μl) containing the LacZ gene (5 × 10⁸ pfu) was injected into rat sciatic nerves or the dorsal root ganglia at the level of L5. The sciatic nerves, the dorsal root ganglia, and the spinal cords were obtained 7, 14, 21, and 28 days after injection. Expression of LacZ was assessed by X-gal histochemistry and β-gal immunohistochemistry. Results Following injection of the adenovirus carrying the LacZ gene into the sciatic nerve, LacZ expression was seen mainly in the Schwann cells and the small neurons in the dorsal root ganglion. In contrast, expression was observed in the primary nerve terminals of the spinal dorsal horn and the small to large dorsal root ganglion neurons and the Schwann cells after injection of the vectors into the L5 dorsal root ganglion. There were no side effects in rats with injection in the dorsal root ganglia or the sciatic nerve. Conclusions The present study shows efficient protein transduction by adenovirus vectors in the PNS. It is noted that injection of the virus into the dorsal root ganglia leads to extensive expression of LacZ in the spinal cord, the dorsal root ganglia, and the sciatic nerves.     

鞘内注射吗啡加可乐定对切口痛大鼠脊髓背角蛋白激酶A催化亚单位表达的影响

Objective To observe the effect of intrathecal clonidine plus morphine on expression of protein kinase A (PKA) catalytic subunit in the spinal dorsal horn in a rat model of incisional pain. Methods Eighty male Sprague-Dawley rats were divided randomly into five groups: sham group, control group, pre-incisional morphine 2.5 μg group, pro-incisional clonidine 5 μg group and preincisional morphine 2.5 μg plus clonidine 5 lag group (n=16). lntrathecal catheter and the model of incisional pain were pro-duced according to Yaksh and Brennan's described method respectively. Changes of pain behavior were assessed by mechanical with-drawal threshold (MWT) and thermal withdrawal latency(TWL). The expressions of PKA catalytic subunit in the spinal dorsal horn were assessed by immunohistochemical method and western blotting analysis. Results Compared with sham group, MWT and TWL in control group were decreased significantly at 2 h after incision (P<0.01) and the number of positive cells and protein expression of PKA catalytic subunit in the spinal dorsal horn were increased significantly in control group (P<0.01). Compared with control group, MWT and TWL in pre-incision morphine 2 μg plus clonidine 5 lag group were increased significantly at 2 h after incision (P<0.01) and the number of positive cells and protein expression of PKA catalytic subunit in the spinal dorsal horn were decreased significantly in pre-incision morphine 2 μg plus clonidine 5 μg group (P<0.01). However, MWT, TWL and the number of positive cells and pro-tein expression of PKA catalytic subunit in the spinal dorsal horn changed with no statistical significance in pre-incisional morphine 2.5 μg group and pre-incisional clonidine 5 μg group compared with control group. Conclusion lntrathecal clonidine significantly enhances the antinociceptive effect of intrathecal morphine in a rat model of incisional pain, which might be associated with inhibi-tion of the increased expression of PKA catalytic subunit in spinal cord.     

神经病理性痛大鼠背根神经节和脊髓背角Nogo-A蛋白表达的变化

目的 评价神经病理性痛大鼠背根神经节和脊髓背角Nogo-A蛋白表达的变化.方法 健康成年雄性SD大鼠72只,体重250～300 g,采用随机数字表法,将大鼠随机分为3组(n=24):对照组(C组)、假手术组(S组)和神经病理性痛组(NP组).C组不做任何处理,NP组采用结扎并剪断胫神经和腓总神经的方法制备大鼠神经病理性痛模型,S组仅切皮暴露坐骨神经但不结扎和剪断神经.于结扎后1、7、14、21 d时采用yon Frey丝测定大鼠机械痛阈.于各时点随机取6只大鼠处死后取损伤侧L5背根神经节和L4,5脊髓,采用免疫荧光标记法测定Nogo-A蛋白的表达(n=3),采用Westernblot法测定Nogo-A蛋白的表达(n=3).结果 与C组和S组比较,NP组大鼠结扎后7、14、21 d时机械痛阈降低,结扎后7、14 d时背根神经节Nogo-A蛋白表达下调,结扎后14、21 d时脊髓背角Nogo-A蛋白表达上调(P＜0.05).结论 背根神经节及脊髓背角Nogo-A蛋白可能在外周神经损伤诱发大鼠神经病理性痛过程中发挥重要作用.

Abstract：

Objective To investigate the changes in the expression of Nogo-A protein in the dorsal root ganglion (DRG) and spinal dorsal horn in a rat model of neuropathic pain (NP) .Methods Seventy-two male SD rats weighing 250-300 g were randomly divided into 3 groups ( n = 24 each) : control group (group C) , sham operation group (group S) and NP group. NP was induced by ligation and severance of tibial and common fibular nerves according to the technique described by Isabelle et al. The mechanical withdrawal threshold (MWT) to von Frey filament stimulation was measured at 1, 7, 14 and 21 days after ligation. Six rats in each group were randomly selected at each time point and sacrificed (3 for determination of Nogo-A protein expression by immunofluorescence, 3 for determination of Nogo-A protein expression by Western blot) . The L5 DRG and L4,5 segment of spinal cord on the injured side were removed for determination of Nogo-A protein expression by immunofluorescence and Western blot. Results Compared with the groups C and S, MWT was significantly decreased at 7, 14 and 21 days after ligation, the expression of Nogo-A protein in the DRG was down-regulated at 7 and 14 days after ligation and the expression of Nogo-A protein in the spinal dorsal horn was up-regulated at 14 and 21 days after ligation ( P ＜0.05) .Conclusion The Nogo-A protein in the DRG and spinal dorsal horn may play an important role in peripheral nerve injury-induced NP in rats.     

Increased phosphorylation of cyclic AMP response element binding protein （CREB） in the dorsal root ganglia and superficial dorsal horn neurons following chronic constriction injury

Objective To investigate whether chronic constriction injury （CCI） of the sciatic nerve of rats could produce alterations in the phosphorylation of cyclic AMP response element binding（CREB） protein in dorsal root ganglia （DRG） and superficial dorsal horn neurons of the spinal cord. Methods Chronic constriction injury （CCI） of the sciatic nerve was employed as a model of neuropathic pain. Thirty-two Sprague-Dawley rats were randomly divided into NaYve, Sham, CCI 2w（received CCI for 2 weeks） and CCI 4w（received CCI for 4 weeks） groups. Hind paw withdrawal threshold to mechanical stimuli and withdrawal latency to thermal stimuli were used to detemline the mechanical and thermal hypemlgesia. Then all the rats were deeply anesthetized and perfused intracardiaUy with paraformaldehyde. The fixed I4-5 spinal cord and the L5 DRG ipsilateml to CCI were harvested for fixation. The pCREB-immunoreactive（pCREB-IR） cells in both DRG and superficial dorsal horn neurons were quantified for analysis using immunohistochemistry methods. Results On the 14th day after sciatic nerve injury, all the rats exhibited significant mechanical and thermal hyperalgesia. The mechanical withdrawal thresholds to yon Frey filament from CCI 2w group decreased significantly compared to both baseline values and those of Sham group（ P 〈 0.01 ） ; Thermal withdwal latencies from CCI 2w group decreased significantly compared to both baseline values and those of Sham group（ P 〈 0.01 ）. Some rats from Sham group also showed mechanical hyperalgesia compared to both baseline values and those of Naive group（ P 〈 0.01）. 28 days after CCI, both mechanical and thermal hypersensitivity were significantly alleviated, with no statistical significance compared to those of Sham group. On the 14th day after CCI, the number of pCREB-IR ceils significantly increased in ipsilateral L5 DRGs and superficial dorsal horns（ P 〈 0.01 ） compared to Sham group. The number of phosphorylated CREB-IR cells in the ipsilateral DRGs from Sham group also increased compared to that of Naive rats（ P 〈 0.05）. There were no significant statistical differences of numbers of CREB-IR neuron between Sham group and CCI 4w group. Conclusion CCI increases CREB phosphorylatian both in DRG and superficial dorsal horn neurons of the lumbar spinal cord, and may be one of the key molecular mechanisms of central and peripheral sensitization following peripheral nerve injury.     

硬膜外注射倍他米松-利多卡因混合液对兔神经根炎症及硬膜外粘连的影响

目的 评价硬膜外注射倍他米松-利多卡因混合液对兔神经根炎症及硬膜外粘连的影响.方法 成年雄性新西兰大白兔24只,体重2.0～2.1 kg,采用随机数字表法,将兔随机分为2组(n=12):对照组和治疗组,在L2,3间隙进行硬膜外穿刺置管,置管后24 h注入消毒滑石粉0.5 mg/kg,制备神经根炎症及硬膜外粘连模型.给予滑石粉后3 d,治疗组经硬膜外导管注射倍他米松0.25mg/kg+利多卡因2.5 mg/kg,对照组给予等容量生理盐水.给予倍他米松+利多卡因后21 d,取脊髓和脊神经根,肉眼、光镜和电镜观察神经根和硬膜的病理学结果,并进行硬膜炎性细胞计数.结果 对照组神经根炎性反应和硬膜外粘连明显.治疗组未见明显和神经根炎性反应硬膜外粘连.治疗组硬膜炎性细胞计数(21±12)明显少于对照组(250±43)(P<0.01).结论 硬膜外注射倍他米松-利多卡因混合液可减轻兔神经根炎症及硬膜外粘连.

Abstract：

Objective To investigate the effects of epidural administration of a mixture of betamethasone and lidocaine on nerve root inflammation and epidural space adhesion in rabbits. Methods Twenty-four adult male New Zealand white rabbits weighing 2.0-2.1 kg, were randomly divided into 2 groups ( n = 12 each): control group and treatment group. A catheter was inserted into epidural space at L2,3 interspace. Twenty-four hour after epidural catheter placement, talcum powder 0.5 mg/kg was injected into epidural space to make the model of nerve root inflammation and epidural space adhesion. Three days later a mixture of lidocaine 2.5 mg/kg and betamethasone 0.25 mg/kg was injected via the epidural catheter in treatment group, while the equal volume of normal saline was given in control group. At 21 days after administration of lidocaine and betamethasone, the spinal cord was removed, and dura mater and nerve root were checked with naked eye, light microscope and electron microscope.The neutrophil count in the dura mater was determined. Results There was nerve root inflammation and epidural space adhesion in control group. The nerve root inflammation and epidural space adhesion was not observed in treatment group. The neutrophil count was reduced in treatment group (21 ± 12) compared with control group (250 ±43) ( P < 0.01) . Conclusion Epidural administration of a mixture of betamethasone and lidocaine can alleviate nerve root inflammation and epidural space adhesion.     

鞘内注射氯胺酮对神经病理性痛大鼠吗啡耐受时脊髓背角突触重塑的影响

目的 探讨鞘内注射氯胺酮对神经病理性痛大鼠吗啡耐受时脊髓背角突触重塑的影响.方法 鞘内置管成功的雄性SD大鼠48只,体重200～250 g,采用随机数字表法,将大鼠随机分为6组(n=8),置管后5 d,神经病理性痛组(NP组)、生理盐水对照组(NS组)、吗啡组(M组)、氯胺酮组(K组)和吗啡+氯胺酮组(MK组)采用背根神经节慢性压迫法制备神经病理性痛模型,假手术组(S组)仅暴露L5椎间孔.背根神经节慢性压迫后1 d NS组鞘内注射0.9%生理盐水20止,M组和K组分别给予吗啡20μg或氯胺酮50μg,MK组给予吗啡20μg+氯胺酮50μg,1次/d,连续14 d.分别于给药前(基础状态)、给药1、3、5、7、9、11、14 d时测定机械缩足阈值(PWT)和热缩足潜伏期(PWL).最后1d给药后立即处死大鼠,取脊髓组织,其中4只采用免疫组织化学方法测定脊髓背角突触数目,另外4只用于测定脊髓背角突触后膜致密物厚度.结果 与S组比较,其余5组PWT降低,PWL缩短,NP组、NS组、M组和K组突触数目和突触后膜致密物厚度增加(P＜0.05);与NP组比较,M组、K组和MK组PWT升高,PWL延长,突触数目和突触后膜致密物厚度降低(P＜0.05);与M组比较,MK组PWT升高,PWL延长,突触数目和突触后膜致密物厚度降低(P＜0.05).结论 鞘内注射氯胺酮可抑制神经病理性痛大鼠吗啡耐受时脊髓背角突触重塑.

Abstract：

Objective To investigate the effects of intrathecal (IT) ketamine on the synapsis remodeling in the spinal dorsal horn during devolopment of morphine tolerance in a rat model of neuropathic pain (NP). Methods Male SD rats weighing 200-250 g were used in this study. IT catheter was placed in the subarachnoid space according to Yaksh. Forty-eight SD rats in which IT catheter was successfully placed were randomly divided into 6groups (n=8 each): group sham operation (group S); group NP; group normal saline 20 μl IT(group NS);group morphine 20 μg IT (group M); group ketamine 50 μg IT (group K) and group morphine 20 μ g + ketamine 50 μg IT (group MK). NP was induced by compression of right L4,5 dorsal root ganglions with steel wire inserted through L4,5 intervertebral foramen in NP,M,K and MK groups. Normal saline or morphine and/or ketamine were injected IT once a day for consecutive 14 days. Paw withdrawal threshold (PWT) to mechanical stimulation and paw withdrawal latency (PWL) to a thermal nociceptive stimulus were measured on 0, 1, 3, 5, 7, 9, 11, 14 days during the consecutive 14 days of administration. The animals were sacrificed after the final IT administration. The lumbar segment of the spinal cord was removed for determination of the number of synapsis in the spinal dorsal horn by immuno-histochemistry in 4 animals in each group and observation of synaptic structure remodeling using electron microscope in another 4 animals in each group. Results Compared with group S, PWT was significantly decreased and PWL was shortened in the other 5 groups, and the number of synapsis was significantly increased and the synaptic structure was thickened in NP, NS, M and K groups (P ＜ 0.05). Compared with group NP,PWT was significantly increased and PWL was prolonged in M, K and MK groups, and the number of synapsis was significantly decreased and the thickness of synaptic structure was significantly reduced in group MK ( P ＜ 0.05).Compared with group M, PWT was significantly increased, PWL was prolonged, the number of synapsis was significantly decreased and the thickness of synaptic structure was significantly reduced in group MK ( P ＜ 0.05). Conclusion IT ketamine can inhibit the synaptic remodeling in the spinal dorsal horn during development of morphine tolerance in a rat model of NP.     

阻断部分臂丛神经下干分支对健侧颈7移位下干后神经再生的影响

Objective To explore the changes of the nerve fibers from median and ulnar nerves after cutting the branches of lower trunk which was repaired by the contralateral C7.Methods Forty female SD rats were divided into A, B, C and D groups randomly.In group A,the contralateral C7 root was transferred to lower trunk directly, and the posterior division of lower trunk, medial anterior thoracic nerve and the medial antebrachial cutaneous nerve were severed at the beginning of them;In group B, the contralateral C7 root was trarsferred to lower trunk directly, and the posterior division of lower trunk, medial anterior thoracic nerve and the medial antebrachial cutaneous nerve were severed at the point which was 1 cm away from the beginning of above branches;In group C, the contralateral C7 root was transferred to lower trunk directly, and the posterior division of lower trunk was severed at the beginning of it;In group D, control group.After the operation, myelinated fiber count, nerve fiber density, the percentage of the number of nerve fiber from branch accounting for that from lower trunk, nerve fiber diameter,the percentage of nerve fibers with different diameters and N Ratio were carried out to evaluate the outcome of each group.Results Myelinated fiber count, nerve fiber density, the percentage of the number of nerve fiber from branch accounting for that from lower trunk, nerve fiber diameter,the percentage of nerve fibers with different diameters and N Ratio in ulnar and median nerve, there were no difference between group A, group B and group C ( P ＞ 0.05).Conclusion After the medial anterior thoracic nerve and medial antebrachial cutaneous nerve, repaired by the contralateral C7, were severed at the beginning and at the point which was 1 cm away from the beginning of above branches, the changes of the quantity and quality of the nerve fibers from median and ulnar nerves were not significant.     

阻断部分臂丛神经下干分支对健侧颈7移位下干后神经再生的影响

Objective To explore the changes of the nerve fibers from median and ulnar nerves after cutting the branches of lower trunk which was repaired by the contralateral C7.Methods Forty female SD rats were divided into A, B, C and D groups randomly.In group A,the contralateral C7 root was transferred to lower trunk directly, and the posterior division of lower trunk, medial anterior thoracic nerve and the medial antebrachial cutaneous nerve were severed at the beginning of them;In group B, the contralateral C7 root was trarsferred to lower trunk directly, and the posterior division of lower trunk, medial anterior thoracic nerve and the medial antebrachial cutaneous nerve were severed at the point which was 1 cm away from the beginning of above branches;In group C, the contralateral C7 root was transferred to lower trunk directly, and the posterior division of lower trunk was severed at the beginning of it;In group D, control group.After the operation, myelinated fiber count, nerve fiber density, the percentage of the number of nerve fiber from branch accounting for that from lower trunk, nerve fiber diameter,the percentage of nerve fibers with different diameters and N Ratio were carried out to evaluate the outcome of each group.Results Myelinated fiber count, nerve fiber density, the percentage of the number of nerve fiber from branch accounting for that from lower trunk, nerve fiber diameter,the percentage of nerve fibers with different diameters and N Ratio in ulnar and median nerve, there were no difference between group A, group B and group C ( P ＞ 0.05).Conclusion After the medial anterior thoracic nerve and medial antebrachial cutaneous nerve, repaired by the contralateral C7, were severed at the beginning and at the point which was 1 cm away from the beginning of above branches, the changes of the quantity and quality of the nerve fibers from median and ulnar nerves were not significant.     

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。     

Dorsal root repair by means of an autologous nerve graft: Experimental study in the rat

Summary Rat dorsal root regeneration was studied after 6th and 7th cervical root surgical removal and replacement with an autologous graft of peripheral nerve harvested from the surval nerve from dorsal root ganglion to dorsal horn. Histological studies showed axonal regeneration within the grafts. When the distal end of the graft was placed inside the posterior horn of the spinal cord by use of a myelotomy, axonal sprouts (revealed by the transganglionic staining method of horseradish peroxidase or HSP) reached the neurones of the posterior horn in a limited fashion.     

Bypassing spinal cord injury: surgical reconstruction of afferent and efferent pathways to the urinary bladder after conus medullaris injury in a rat model

Afferent and efferent nerve function in the atonic bladder caused by conus medullaris injury in a rat model was established by intradural microanastomosis of the left L5 ventral root (VR) to right S2 VR to restore pure motor-to-motor reinnervation coupled with extradural postganglionic spinal nerve transfer of L5 dorsal root (DR) to S2 DR for pure sensory-to-sensory reinnervation. Early function of the reflex arc was evaluated by electrophysiological study, as well as by intravesicular pressure measurement and histological examination. The results demonstrated that single focal stimulation of the left S2 DR elicited evoked potentials at the left vesicular plexus before and after horizontal spinal cord damage between the L6 and S4 level. Bladder contraction was successfully initiated by trains of stimuli targeting the left L5-S2 DR anastomosis. Achievable bladder pressures and amplitude of bladder smooth muscle complex action potentials were unchanged before and after induced paraplegia and comparable to those of the control. Prominent axonal sprouting was seen in the distal part of nerve graft. Both afferent and efferent nerve pathways in the atonic bladder can be reconstructed by suprasacral motor-to-motor and sensory-to-sensory nerve transfer after spinal cord injury in rats. This reconstructive strategy has significant potential in clinical application.     

Clinical and electrophysiological expression of deafferentation pain alleviated by dorsal root entry zone lesions in rats

OBJECT: The aims of this study were to construct an animal model of deafferentation of the spinal cord by brachial plexus avulsion and to analyze the effects of subsequent dorsal root entry zone (DREZ) lesions in this model. To this end, the authors measured the clinical and electrophysiological effects of total deafferentation of the cervical dorsal horn in rats and evaluated the clinical efficacy of cervical DREZ lesioning. METHODS: Forty-three Sprague-Dawley rats were subjected to total deafferentation of the right cervical dorsal horn by performing a posterior rhizotomy from C-5 to T-1. The clinical effects of this deafferentation, namely self-directed mutilations consisting of scraping and/or ulceration of the forelimb skin or even autotomy of some forelimb digits, were then evaluated. As soon as some of these clinical signs of pain appeared, the authors performed a microsurgical DREZ rhizotomy ([MDR], microincision along the deafferented DREZ and dorsal horn). Before and after MDR, single-unit recordings were obtained in the deafferented dorsal horn and in the contralateral (healthy) side. The mean frequency of spontaneous discharge from the deafferented dorsal horn neurons was significantly higher than that from the healthy side (36.4 Hz compared with 17.9 Hz, p = 0.03). After deafferentation, 81.4% of the rats developed clinical signs corresponding to pain following posterior rhizotomy. Among these animals, scraping was observed in 85.7% of cases, ulceration (associated with edema) in 37.1%, and autotomy in 8.5%. These signs appeared a mean 5.7 weeks (range 1-12 weeks) after deafferentation. Thirteen rats benefited from an MDR; nine (69%) experienced a complete cure, that is, a total resolution of scraping or ulceration (a mean 4.6 weeks after MDR). In contrast, only one of 11 sham-operated animals showed signs of spontaneous recovery (p = 0.01). CONCLUSIONS: These results emphasize the role of the spinal dorsal horn in the genesis of deafferentation pain and suggest that dorsal horn deafferentation by cervical posterior rhizotomy in the rat provides a reliable model of chronic pain due to brachial plexus avulsion and its suppression by MDR.     

Microsurgical anatomy of dorsal root entry zone of brachial plexus

The purpose of this study was to describe microsurgical anatomy of the dorsal root entry zone (DREZ) and provide an anatomic basis for the approach of DREZ lesion in treating radiculopathy of brachial plexus avulsion injuries. We studied 100 dorsal cervical roots and DREZ/posterior horn complexes in 20 adult cadavers. At each root level the following data were recorded: widths of laminectomy, numbers of posterior rootlets, angle of the inferior rootlets with the spinal cord, and distance from posterior median sulcus to posterolateral sulcus. On cross-sectional plane, the length and width of dorsal horn and the angle between longitudinal axis of dorsal horn and sagittal plane of spinal cord were measured. The results showed that the spinal cord segment and the entry of dorsal roots from C5 to T1 were exposed clearly after laminectomy from C4 to C7. The average number of roolets of C5-T1 roots was about 7.76 and C6 has the most. From up to down, the angle from the inferior rootlet to spinal cord of C5-T1 diminished gradually. The average distance from posterior median sulcus to posterolateral sulcus was 2.95 mm. The average length, width, and angle of posterior horn were 3.47 mm, 1.346 mm, and 35.9 degrees , respectively. Our study demonstrated that the spinous process and lamina of the C4 to C7 vertebrae should be resected to expose the C5-T1 when DREZ lesions are employed to treat pain after brachial plexus avulsion. The lesion-making apparatus should be inserted at an angle of 30 degrees -40 degrees , the width of lesion should be less than 1.2 mm and the lesion depth less than 3.1 mm.     

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.     

鼠腓总神经端侧缝合后脊髓内HRP阳性标记神经细胞出现的时间和数量

目的用辣根过氧化物酶（ｈｏｒｓｅｒａｄｉｓｈｐｅｒｏｘｉｄａｓｅ,ＨＲＰ）追踪法比较神经端侧缝合与对端缝合后脊髓内神经细胞出现的时间和数量。方法Ｗｉｓｔａｒ大鼠３６只,切断其右侧腓总神经后,按手术方法随机分为３组,每组１２只。（Ａ）端侧吻合组：腓神经远断端与胫神经侧方窗口缝合。（Ｂ）对端缝合组：腓总神经近、远端作对端缝合。（Ｃ）对照组：腓总神经不作缝合。术后２、４、６、８、１０及１２周,３组各取２只鼠,自腓总神经最远端注射０．１μｌＨＲＰ（３０％）,７２小时后取出大鼠Ｔ１２～Ｌ６脊髓节段和相应的后根神经节,作组织学观察。结果Ａ组：术后１２周时,同侧Ｌ２～５后根神经节,脊髓后角、前角出现典型的ＨＲＰ阳性标记细胞,比Ｂ组慢６周。细胞数量比Ｂ组少４５．７％（ｔ＝４．９２,Ｐ＜０．０１）。Ｃ组则一直未见ＨＲＰ阳性标记细胞。结论神经端侧缝合后可以再生,但其速度和阳性细胞数量均较对端缝合差。     

臂丛神经根性撕脱伤后神经根回植的实验研究

目的探讨臂丛神经根性撕脱伤后，神经根回植脊髓对前角运动神经元的挽救效应及作用机制，观察回植后神经根的生长情况。方法成年Wistar大鼠30只，随机分两组，每组15只。取两组大鼠左侧为正常对照侧，不作任何处理；右侧进行模型制备。进行C4-6右侧椎板减压，于椎管内硬膜外撕脱C5、6神经根。实验组将C5神经前根回植入脊髓前角，用11—0无创缝线缝合2针，后根旷置，C5神经根埋入周围肌肉；对照组将撕脱的C5、6神经根埋入肌肉。术后2、4、6、8及12周取材，C6脊髓HE染色，观察脊髓前角运动神经元的形态和数量的变化；C6神经根作硝酸银染色，观察神经纤维的再生情况。结果两组大鼠术后均表现为右上肢上干瘫痪，余肢体活动正常。对照组撕脱的神经根与周围肌肉粘连；实验组神经根植入脊髓处有较多瘢痕组织粘连，未见神经根从脊髓上脱落。各时间点HE染色显示，实验组运动神经元胞体萎缩，部分运动神经元水肿，尼氏体减少或消失；对照组神经细胞胞体缩小。术后各时间点对照组脊髓前角运动神经元成活率分别为60．9％±5．8％、42．3％±3．5％、30．6％±6．1％、27．5％±7．9％及20．4％±6．8％，实验组为67．1％±7．4％、56．3％土4．6％、48．7％±8．8％、44．2％±5．5％及42．5％±8，3％，差异有统计学意义（P〈0．01）。硝酸银染色显示，实验组C6神经根硝酸银染色显示前角运动神经元能通过轴突再生进入回植的神经根内；对照组显示为神经纤维的退变，有髓神经纤维数目减少。结论臂丛神经根性撕脱伤后前根回植脊髓后，能够明显减少前角运动神经元的变性死亡。神经根回植后，运动神经元能通过轴突再生进入回植的神经根内，并有新生的有髓神经纤维生长。     

Subpial spinal evoked potentials in patients undergoing junctional dorsal root entry zone coagulation for pain relief

Summary Seven patients with complete avulsion of the brachial plexus underwent junctional coagulation lesions of the dorsal root entry zone (DREZ) for relief of intractable pain in the paralyzed arm. Intra-operative monitoring by recording spinal cord somatosensory evoked potentials (SEP) resulting from tibial nerve stimulation was done using subpial recording electrodes situated dorsal to the posterior median sulcus at the C4 and T2 segment. SEP on the normal side showed an initial positive wave and two negative waves followed by a group of high frequency waves of relatively high amplitude which continued into high frequency, low amplitude potentials. The conduction velocity of the fastest spinal evoked potential components were, on average, 86 m/s. Recordings from the side of avulsion revealed a steep positive potential of high amplitude which appeared in five patients prior to the creation of the DREZ lesion. This effect was assumed to be secondary to spinal cord damage caused by avulsion. During the DREZ coagulation the SEP from the unaffected side did not change. On the side of DREZ coagulation the velocity of the fastest fibres decreased. Four patients reported sensory deficits after the operation, which were transient in three. In one of these patients, the first two negative potentials disappeared. In the fourth patient, who had permanent sensory deficits, the positive steep potential appeared after generation of the lesion. Our results point to the usefulness of the subpial SEPs monitoring during microneurosurgical procedures on the spinal cord to provide further insight into evoked electrical activity of the normal and injured spinal cord, and to minimize post-operative neurological morbidity.     

腰神经根病致背根神经节受损的实验研究

目的　探讨神经根受压后对背根神经节的影响。　方法　 SD大鼠 50只。参照 Kawakami方法 ,显露左侧 L4～ 6神经根及背根神经节 ,用 4/0肠线于背根神经节头侧端结扎神经根两道打两个结 ,线与神经根相距 3 mm;自身右侧神经根为对照。术后 1、2、4、8和 1 2周 ,分别取 L4～ 6脊髓节段标本 ,依 Gomori法检测抗氟化物酸性磷酸酶 (FRAP)活性 ,并用图像分析。　结果　实验侧术后 4周 ,脊髓后角 FRAP含量开始降低 ,在所观察的 1 2周内 FRAP随时间延长 ,其含量降低 ,与对照侧比较有统计学意义 (P<0 .0 1 )。　结论　腰神经根慢性受压对背根神经节有损害