SD大鼠马尾与骶神经根的解剖学观察

目的：为从马尾和骶神经根途径开展SD大鼠的神经泌尿学研究提供解剖依据。方法：对6只SD大鼠灌注后进行显微解剖，并对30只SD大鼠进行术中观察和测量，总结马尾、骶神经根的解剖特征。结果：SD大鼠的盆底器官主要由Sl～S4脊髓节段和神经根支配，脊髓圆锥延续较长，达L4椎体下缘，马尾神经亦较长，其前根1束较细，后根2束较粗，包于同一硬脊膜中，硬脊膜较厚而坚韧，脊髓神经前后根出硬脊膜后，有各自独立的硬脊膜囊包绕，直至椎管内硬脊膜囊两侧的后根神经节处，长约3个椎体高度。在4对骶神经根中，以Sl和S2较粗，S3、S4较细。盆神经副交感神经纤维主要来源于S2骶髓节段。结论：SD大鼠骶和尾神经根的解剖特征与人类不同。     

脊髓圆锥部SPR和SAR手术脊神经根辨认的应用解剖学

目的 :为脊髓圆锥部进行SPR和SAR手术提供定位、入路和辨认神经根的解剖学依据。方法 :选 14具儿童脊柱标本 ,显露脊髓圆锥及其马尾神经。观测该区域神经根位置、形态及其与周围组织的关系。结果 :脊髓圆锥末端大多数平对L1椎板。L1神经根硬膜出口亦位于L1椎板范围内 ,神经根在该区域按顺序排列。S1后根最粗 ,S2 明显变细 ,S3～ 5最细。神经后根进入脊髓角度以L5最大 ,S1其次 ,S2 角度骤然变小 ,与脊髓接近平行。结论 :仅处理L1椎板即可满意显露所需处理的神经根。 6cm皮肤切口即可达显露要求。根据终丝 ,L1神经根硬膜出口 ,S1和S2 的形态特征以及节段血管等四个方面综合鉴别能准确辨认神经根。     

SD大鼠腰神经根的解剖学观察

目的　为从腰神经根途径开展脊髓损伤后肢体运动功能重建的研究提供解剖依据。 方法　对10只SD大鼠灌注后进行显微解剖研究,并对30只SD大鼠进行手术中观察和测量,观察腰神经根的解剖特点。 结果　SD大鼠腰神经根共有6对,其中L2~4组成股神经支配股四头肌,L5~6组成坐骨神经支配股后肌群,腰髓约平对T12,13及L1、2水平。腰神经前根1束较细,后根2束较粗,腰神经前、后根出硬膜后,有各自独立的硬膜囊包绕后直至后根神经节处。 结论　SD大鼠腰神经根解剖特征与人类不同。     

骶神经根对盆底器官的选择性支配电刺激实验研究

目的：研究骶神经根对盆底器官逼出肌和括约肌的功能支配,为临床从骶神经根角度重建脊髓损伤（ＳＣＩ）后的排汇功能提供依据。方法：对Ｔ１０截瘫犬进行硬膜外Ｌ７～Ｓ３神经根电刺激,１６只犬同时记录膀胱和尿道压力变化;７只犬同时记录直肠和肛门压力变化。结果：犬逼尿肌的神经支配以Ｓ２为主,Ｓ１次之;Ｓ２单独提供了膀胱压力增高值的４５．２％,Ｓ１＋Ｓ２提供了８０．７％。尿道插约肌的神经支配以Ｓ１为主,Ｓ２次之;     

用胸—骶神经根桥接治疗截瘫性大小便失禁的新术式

在20具成尸标本上解剖观测了第10胸神经～第3腰神经前、后根的长度、分束、各束直径以及它们的末端至第2～4骶神经根起始处的距离。设计了在椎管内用马尾神经桥接胸—骶神经根治疗截瘫性大、小便失禁的新术式,并就与该术式有关的应用解剖学问题进行了讨论。     

脊髓圆椎部SPR和SAR手术脊神经根辨认的应用解剖学

目的：为脊髓圆椎部进行ＳＰＲ和ＳＡＲ手术提供定位、入路和辨认神经根的解剖学依据。方法：选１４具儿童脊柱标本,显露脊髓圆椎及其马尾神经。观测该区域神经根位置、形态及其与周围组织的关系。结果：脊髓圆椎末端大多数平对Ｌ１椎板,Ｌ１椎板根硬膜出口亦位于Ｌ１椎板范围内,神经根在该区域按顺序排列。Ｓ１后根最粗,Ｓ２明显变细,Ｓ３～５最细,神经后根进入脊髓角度以Ｌ５最大,Ｓ１其次,Ｓ２角度骤然变小,与脊髓接近平     

利用跟腱反射重建膀胱功能的应用解剖学研究

目的 :为进行跟腱反射重建膀胱功能的手术时脊神经前根和吻接平面的选择以及脊神经前根的定位提供解剖学依据。方法 :在 2 0具尸体标本上追踪骶丛和坐骨神经的脊神经根来源、相应的脊神经根在坐骨神经和其它神经之间的分布 ,同时观察硬膜内L4～S4脊神经前根排列的位置关系、相互重叠长度和横截面积。结果 :(1)骶丛主要由L4、L5和S1～ 5脊神经根组成 ,其中L5脊神经根 (4 6% )的贡献最大 ;(2 )S2～ 4前根出脊髓的平面均高于L4、L5和S1前根出硬膜的平面 ,前根的横截面积L4(2 .19± 0 .3 9)mm2 、L5(2 .5 8± 0 .5 8)mm2 和S1(2 .19± 0 .42 )mm2 均显著大于S2～ 4前根 ;(3 )在脊髓圆锥平面 ,前后根的辨别和序列的确认较圆锥下容易。结论 :(1)利用跟腱反射重建膀胱功能时宜选用L5前根与S3 或S4前根交叉吻接 ;(2 )吻接平面宜选择在脊髓圆锥处。     

骶神经损伤对家犬膀胱功能和后肢肌力影响的实验研究

目的：研究不同节段骶神经对膀胱功能和后肢肌力的影响。方法：对12只正常家犬进行选择件S1～S3神经离断术,分别于术后1,3,7,14天及1月用尿流动力学测压仪测量其膀胱压力容积,并观察其后肢肌力变化。结果：双侧S1S2神经的损伤对犬膀胱功能和后肢肌力影响最大。结论：骶神经损伤的节段不同对膀胱功能和后肢肌力的影响具有显著区别。     

长期置入骶神经根刺激电极的兔组织学变化及其安全性

背景：有研究表明基于阳极阻滞技术的骶神经根刺激器能有效重建脊髓损伤兔的膀胱排尿功能,但符合此技术的刺激电极至今未见报道。 目的：设计并研制既与兔骶神经根匹配又符合阳极阻滞技术的刺激电极,观察长期植入刺激电极的兔骶神经根超微结构及病理形态学变化,评估刺激电极安全性。 方法：纳入新西兰兔30只,随机抽取10只兔切取双侧S2及S3神经前根,光镜下测量其直径后,制成与其直径相匹配的套筒型刺激电极。将剩余20只兔随机分为对照组及植入组,每组10只。植入组麻醉后将刺激电极植入S2及S3神经根前处,饲养半年后处死取材,观察植入处骶神经根超微结构变化。 结果与结论：长期植入该刺激电极后,光学显微镜下见植入组植入处骶神经根神经细胞结构保存良好,轴突无明显变性,无炎症细胞浸润及胶质瘢痕形成;透射电镜下观察,植入组髓鞘排列紧密,无脱髓鞘现象,神经元无核萎缩、核凹陷和异染色质增多等现象。免疫组织化学染色显示,与对照组相比,植入组植入处神经根中胶质纤维酸性蛋白、Bax,Bcl-2和Caspase-3蛋白表达差异无显著性意义。结果说明实验成功研制了兔骶神经根刺激电极,长期植入骶神经根未出现组织病理学改变及无细胞凋亡现象,安全性好。     

不同骶神经根对膀胱逼尿肌的支配作用及临床意义

目的 :确定不同骶神经根对膀胱的支配频率和支配效能。方法 :总结在 10例圆锥上脊髓损伤患者 ,从马尾骶神经根途径进行膀胱功能重建时术中骶神经根电刺激的膀胱测压结果。结果 :对膀胱的支配频率 ,S3 占 10 0 % ,S4占 90 % ,S2 占 2 5 % ;对膀胱的支配效能 ,S3 占 5 2 .2 % ,S4占 44 .9% ,S2 占 2 .5 %。 (S3 S4)提供了膀胱压力的 97% ,S2 无论在支配频率和支配效能方面 ,作用均很小。结论 :膀胱逼尿肌的神经支配主要由S3 和S4提供。     

Cauda equina syndrome

Single or double-level compression of the lumbosacral nerve roots located in the dural sac results in a polyradicular symptomatology clinically diagnosed as cauda equina syndrome. The cauda equina nerve roots provide the sensory and motor innervation of most of the lower extremities, the pelvic floor and the sphincters. Therefore, in a fully developed cauda equina syndrome, multiple signs of sensory disorders may appear. These disorders include low-back pain, saddle anesthesia, bilateral sciatica, then motor weakness of the lower extremities or chronic paraplegia and, bladder dysfunction. Multiple etiologies can cause the cauda equina syndrome. Among them, non-neoplastic compressive etiologies such as herniated lumbosacral discs and spinal stenosis and spinal neoplasms play a significant role in the development of the cauda equina syndrome. Non-compressive etiologies of the cauda equina syndrome include ischemic insults, inflammatory conditions, spinal arachnoiditis and other infectious etiologies. The use of canine, porcine and rat models mimicking the cauda equina syndrome enabled discovery of the effects of the compression on nerve root neural and vascular anatomy, the impairment of impulse propagation and the changes of the neurotransmitters in the spinal cord after compression of cauda equina. The involvement of intrinsic spinal cord neurons in the compression-induced cauda equina syndrome includes anterograde, retrograde and transneuronal degeneration in the lumbosacral segments. Prominent changes of NADPH diaphorase exhibiting, Fos-like immunoreactive and heat shock protein HSP72 were detected in the lumbosacral segments in a short-and long-lasting compression of the cauda equina in the dog. Developments in the diagnosis and treatment of patients with back pain, sciatica and with a herniated lumbar disc are mentioned, including many treatment options available.     

Reimplantation of avulsed lumbosacral ventral roots in the rat ameliorates injury-induced degeneration of primary afferent axon collaterals in the spinal dorsal columns

Injuries to the cauda equina/conus medullaris portion of the spinal cord can result in motor, sensory, and autonomic dysfunction, and neuropathic pain. In rats, unilateral avulsion of the motor efferents from the lumbosacral spinal cord results in at-level allodynia, along with a corresponding glial and inflammatory response in the dorsal horn of the spinal cord segments immediately rostral to the lesion. Here, we investigated the fate of intramedullary primary sensory projections following a motor efferent lesion. The lumbosacral (L6 and S1) ventral roots were unilaterally avulsed from the rat spinal cord (VRA; n=9). A second experimental group had the avulsed roots acutely reimplanted into the lateral funiculus (Imp; n=5), as this neural repair strategy is neuroprotective, and promotes the functional reinnervation of peripheral targets. A laminectomy-only group served as controls (Lam; n=7). At 8 weeks post-lesion, immunohistochemical examination showed a 42% reduction (P<0.001) in the number of RT97-positive axons in the ascending tracts of the dorsal funiculus of the L4-5 spinal segment in VRA rats. Evidence for degenerating myelin was also present. Reimplantation of the avulsed roots ameliorated axon and myelin degeneration. Axons in the descending dorsal corticospinal tract were unaffected in all groups, suggesting a specificity of this lesion for spinal primary sensory afferents. These results show for the first time that a lesion restricted to motor roots can induce the degeneration of intramedullary sensory afferents. Importantly, reimplantation of the lesioned motor roots ameliorated sensory axon degeneration. These data further support the therapeutic potential for reimplantation of avulsed ventral roots following trauma to the cauda equina/conus medullaris.     

脊神经前后根的应用显微解剖学研究

目的　探讨脊神经前后根神经小束的分束标准和数目 ,为临床手术提供可靠的依据和新的手术标准。方法　在 15例 (30侧 )成人脊柱标本上 ,对L1～S2节段的脊神经前后根进行形态学观察和显微测量。结果　脊髓圆锥部脊神经根是由根丝逐步汇合而成。应用显微外科技术 ,后根一般可分为 10～ 18小束 ,前根一般分为 6～ 11小束 ,其小束的直径是基本一致 ,数值较为恒定。结论　在高选择性手术 ,脊神经前后根的分束标准应尽量细 ,这样有利于准确切断引起痉挛的Ia类神经纤维 ,一般前根达到 6～ 11小束 ,后根达到 10～18小束     

Cauda equina syndrome with multiple lumbar diverticula complicating long-standing ankylosing spondylitis

A patient with cauda equina syndrome complicating long-standing inactive ankylosing spondylitis is described. The first neurological symptoms started 15 years after the onset of ankylosing spondylitis. Over a follow-up period of 12 years the cauda equina syndrome showed a slowly progressive but disabling course leading to sensory disturbances in the lumbar and sacral dermatomes, weakness and wasting of the muscles innervated by these nerve roots, sphincter disturbances, and impotence. Magnetic resonance imaging, computed tomography, and lumbar myelography showed enlargement of the dural sac with multiple lubar diverticula eroding the lumbosacral vertebrae. The pathophysiology of the cauda equina syndrome in ankylosing spondylits is unclear. Surgical treatment seems justified only in patients with a short history of neurological symptoms. Correspondence to: R. Schröder     

Incipient cauda equina syndrome as a model of somatovisceral pain in dogs: spinal cord structures involved as revealed by the expression of c-fos and NADPH diaphorase activity

Segmental and laminar distribution of Fos-like immunoreactive, reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd)-exhibiting and double-labeled (Fos-like immunoreactive and NADPHd-exhibiting) neurons was examined in lower lumbar and sacral segments of the dog spinal cord using the model of multiple cauda equina constrictions. NADPHd histochemistry was used as marker of nitric oxide synthase-containing neurons. The appearance and the time-course of Fos-like immunoreactive, NADPHd and double-labeled neurons was studied at 2 h and 8 h postconstriction characterized as the incipient phase of cauda equina syndrome. The occurrence of Fos-like immunoreactive and NADPHd-exhibiting neurons in fully developed cauda equina syndrome was studied at five days postconstriction. An increase in Fos-like immunoreactivity in superficial laminae (I-II) and an enhanced NADPHd staining of lamina VIII neurons were found. A statistically significant increase in Fos-like immunoreactive neurons was found in laminae I-II and VIII-X 8 h postconstriction, and in contrast, a prominent decrease in Fos-like immunoreactive neurons was found in laminae I-II, accompanied by a statistically significant increase in Fos-like immunoreactive neurons in more ventrally located laminae VII-X at five days postconstriction. Quantitative analysis of laminar distribution of constriction-induced NADPHd-exhibiting neurons revealed a considerable increase in these neurons in laminae VIII-IX 8 h postconstriction and a statistically highly significant increase in NADPHd-exhibiting neurons in laminae VII-X five days postconstriction. Concurrently, the number of NADPHd-exhibiting neurons in laminae I-II was greatly reduced. While a low number of double-labeled neurons was found throughout the gray matter of lower lumbar and sacral segments at 2 h postconstriction, a statistically significant number of double-labeled neurons was found in lamina X 8 h and in laminae VII-X five days postconstriction. The course and distribution of anterograde degeneration resulting five days after multiple cauda equina constrictions are compared with segmental and laminar distribution of Fos-like immunoreactive and NADPHd-exhibiting neurons. Prominent involvement of the spinal cord neurons appearing in the lumbosacral segments at the early beginning and in fully developed cauda equina syndrome results in a Fos-like immunoreactivity and strongly enhanced NADPHd staining of some neuronal pools. Under such circumstances, an early cauda equina decompression surgery is advisable aimed at decreasing or preventing the derangement of the neural circuits in the lumbosacral segments.     

腰骶部脊神经根的临床解剖学

通过临床选择性脊神经后根切断术中观察与测量,为临床提供了重要的参考数据。腰骶神经前、后根解剖会合点至椎间孔距离平均为1.5～2.0cm。前后两根相比,后根明显较前根粗,其中以L_5后根最粗、L_2～S_1各后根内小束的数目为4～18束,平均为7束,临床分离后根时可分为7束,以便进行电刺激选择。这些资料为腰骶部选择性脊神经后根切断术和马尾神经的手术提供了重要依据。     

Lumbar intrathecal ligaments

A meticulous examination was performed on 56 vertebral columns from cadavers between 64 and 89 years of age. Identification of all contents within the dural sac was completed; however, the main focus was the cauda equina and lumbar region. In addition to scope dissection, radiographs and histological preparations were used to identify structures, tissue types, and any possible pathology. Discrete intrathecal ligamentous bands were observed in all cadavers examined. They were found randomly binding the dorsal nerve roots of the cauda equina to the dura. Occasional binding of the ventral nerve roots to the dorsal roots was observed. Histological examination demonstrated a dense collagen ligament varying between 0.13 and 0.35 microm in thickness and from 3 mm to 3.5 cm in length. The average number of ligaments found per cadaver was 18. These ligaments displayed a broad base attachment to the nerve root or dura of approximately 3 mm. Looping of the nerve roots associated with these ligaments was seen in one cadaver with a burst fracture. Electron microscopic studies of these ligaments demonstrated similarities to denticulate ligaments. It is suggested that the intrathecal ligaments represent remnants from fetal development of the denticulate ligaments.     

Incipient cauda equina syndrome as a model of somatovisceral pain in dogs: spinal cord structures involved as revealed by the expression of c-fos and NADPH diaphorase activity

Segmental and laminar distribution of Fos-like immunoreactive, reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd)-exhibiting and double-labeled (Fos-like immunoreactive and NADPHd-exhibiting) neurons was examined in lower lumbar and sacral segments of the dog spinal cord using the model of multiple cauda equina constrictions. NADPHd histochemistry was used as marker of nitric oxide synthase-containing neurons. The appearance and the time-course of Fos-like immunoreactive, NADPHd and double-labeled neurons was studied at 2 h and 8 h postconstriction characterized as the incipient phase of cauda equina syndrome. The occurrence of Fos-like immunoreactive and NADPHd-exhibiting neurons in fully developed cauda equina syndrome was studied at five days postconstriction. An increase in Fos-like immunoreactivity in superficial laminae (I–II) and an enhanced NADPHd staining of lamina VIII neurons were found. A statistically significant increase in Fos-like immunoreactive neurons was found in laminae I–II and VIII–X 8 h postconstriction, and in contrast, a prominent decrease in Fos-like immunoreactive neurons was found in laminae I–II, accompanied by a statistically significant increase in Fos-like immunoreactive neurons in more ventrally located laminae VII–X at five days postconstriction. Quantitative analysis of laminar distribution of constriction-induced NADPHd-exhibiting neurons revealed a considerable increase in these neurons in laminae VIII–IX 8 h postconstriction and a statistically highly significant increase in NADPHd-exhibiting neurons in laminae VII–X five days postconstriction. Concurrently, the number of NADPHd-exhibiting neurons in laminae I–II was greatly reduced. While a low number of double-labeled neurons was found throughout the gray matter of lower lumbar and sacral segments at 2 h postconstriction, a statistically significant number of double-labeled neurons was found in lamina X 8 h and in laminae VII–X five days postconstriction. The course and distribution of anterograde degeneration resulting five days after multiple cauda equina constrictions are compared with segmental and laminar distribution of Fos-like immunoreactive and NADPHd-exhibiting neurons.Prominent involvement of the spinal cord neurons appearing in the lumbosacral segments at the early beginning and in fully developed cauda equina syndrome results in a Fos-like immunoreactivity and strongly enhanced NADPHd staining of some neuronal pools. Under such circumstances, an early cauda equina decompression surgery is advisable aimed at decreasing or preventing the derangement of the neural circuits in the lumbosacral segments.     

Microsurgical Anatomy of Lumbosacral Nerve Rootlets for Highly Selective Rhizotomy in Chronic Spinal Cord Injury

It is known that selective sacral roots rhizotomy is effective for relieving the neurogenic bladder associated with spinal cord injury. The goal of this study is to review the surgical anatomy of the lumbosacral nerve rootlets and to provide some morphological bases for highly selective sacral roots rhizotomy. Spinal cord dissections were performed on five cadavers under surgical microscope. At each spinal cord segment, we recorded the number, diameter and length of the rootlets, subbundles and bundles from the L1 to S2 spinal segments, and the length of the dorsal/ventral root entry zone. Peripheral nervous system myelin was examined by immunohistochemistry. We found: (1) the ventral or the dorsal root of the lumbosacral segment of the spinal cord was divided into one to three nerve bundles and each bundle was subdivided into one to three subbundles. Each subbundle further gave out two to three rootlets connected with the spinal cord; (2) there were no significant differences in the number of rootlets within the L1 to S2 segments, but the size of rootlets and the length of nerve roots varied (P < 0.05); and (3) the more myelinated fibers a rootlet contained, the larger transection area it had. The area of peripheral nervous system myelin positive cells and the total area of rootlets were correlated (P < 0.001). Thus, during highly selective sacral roots rhizotomy, the ventral and dorsal roots can be divided into several bundles of rootlets, and we could initially distinct the rootlets by their diameters. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

A single re-implanted ventral root exerts neurotropic effects over multiple spinal cord segments in the adult rat

Spinal cord injuries, particularly traumatic injuries to the conus medullaris and cauda equina, are typically complex and involve multiple segmental levels. Implantation of avulsed ventral roots into the spinal cord as a repair strategy has been shown to be neuroprotective and promote axonal regeneration by spinal cord neurons into an implanted root. However, it is not well known over what distance in the spinal cord an implanted ventral root can exert its neurotropic effect. Here, we investigated whether an avulsed L6 ventral root acutely implanted into the rat spinal cord after a four level (L5–S2) unilateral ventral root avulsion injury may exert neurotropic effects on autonomic and motor neurons over multiple spinal cord segments at 6 weeks postoperatively. Using retrograde labeling techniques and stereological quantification methods, we demonstrate that autonomic and motor neurons from all four lesioned spinal cord segments, spanning more than an 8 mm rostro-caudal distance, reinnervated the one implanted root. The rostro-caudal distribution suggested a gradient of neurotropism, where the axotomized neurons closest to the implanted site had the highest probability of root reinnervation. These results suggest that implantation of a single ventral root may provide neurotropic effects to injured neurons at the site of lesion as well as in the adjacent spinal cord segments. Our findings may be of translational research interest for the development of surgical repair strategies after multi-level conus medullaris and cauda equina injuries, in which fewer ventral roots than spinal cord segments may be available for implantation.