改良高选择性脊神经后根部分切断术中前后根神经分束的应用解剖

背景:高选择性脊神经后根部分切断术中前后根的神经分束应达到神经小束水平,分束越多越利于电刺激选择,利于准确地切断阈值低的引起痉挛的Ia类神经纤维,也越可能最大限度地保留后根中的感觉神经纤维.目的:根据限制性和高选择性脊神经后根切断术的要求,对脊神经前后根进行显微解剖,确定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.设计:以成人尸体标本为观察对象,单一样本实验.单位:锦州医学院附属第一医院骨科和锦州医学院解剖教研室.对象:实验于1999-12在锦州医学院解剖学实验室进行.以志愿捐献的15具成人尸体标本为观察对象,男11具,女4具,生前均签署志愿捐献书.方法:①在15具(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.②取新鲜尸体的L5脊神经前后根进行免疫组化染色,将脊神经后根起始部、中间部和椎间孔外部3个部位切片,分别测定神经纤维总数、引起痉挛的Ia类神经纤维的数目及其占神经纤维总数的百分率,比较3个部位Ia类神经纤维的分布规律和数量.主要观察指标:①脊神经根神经分束情况及神经小束的直径.②脊神经后根起始部、中间部和椎间孔外部计数100 μm2神经纤维总数及Ia类神经纤维占神经纤维总数的百分率.结果:①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样,数值较为恒定.②脊神经后根起始部、中间部和椎间孔外部计数100μm2总的神经纤维数为(3 243±143)根,Ia类神经纤维为(1 702±85)根,占总神经纤维数的52.5%.Ia类神经纤维在后根内呈均匀分布,没有集中分布区.结论:改良脊神经后根部分切断术的最大特点即脊神经前后根的分束标准应尽量细,这样有利于准确切断Ia类神经纤维,一般前根达到6～11小束,后根达到10～18小束,切断最大比例应不超过后根神经纤维总数的1/2.

Applied anatomy of anterior and dorsal root nerve tracts in the improved high selective dorsal rhizotomy

BACKGROUND: Anterior and dorsal root nerve tracts should be separated to small tracts in high selective dorsal rhizotomy, because detailed tract separation will benefit electrostimulation, thereby helping correctly cutting the lower-threshold Ia nerve fibers that cause convulsion, and meanwhile sensory nerve fibers in dorsal nerve root can be reserved as many as possible.OBJECTIVE: To meet the needs of limited and high selective spinal dorsal rhizotomy, anterior and dorsal root of spinal nerve were microanatomized to be certain of the separation standard and the number of small nerve tracts, so as to provide reliable basis and novel operative standard for clinical operation.DESIGN: Single sample experiment with adult corpses as subjects.SETTING: Orthopedic Department of the First Affiliated Hospital and Department of Anatomy, Jinzhou Medical College.PARTICIPANTS: This study was carried out at the Anatomical Laboratory of Jinzhou Medical College in December 1999. Fifteen adult corpses, 11 males and 4 males, were donated, and the donators signed informed consent when alive.tained from the 15 adult spinal cords (30 sides) and subjected to morphoanterior and dorsal roots of L5 spinal cord were obtained from a fresh corpse for immunohistochemical staining. The starting part, middle part and the exterior of intervertebral foremen was cut into slices, and the total number of nerve fibers, the number of Ia nerve fibers responsible for convulsion, and their percentage in the total fibers were counted. Meanwhile the distribution and the number of Ia nerve fibers in the three parts were compared.ber of nerve fibers per 100 μm2, the percentage of Ia nerve fibers in the total nerve fibers at the starting part, middle part and exterior of intervertebral foremen of spinal nerve dorsal root.root filaments. Microsurgical observation proved that dorsal root could be divided into 10-18 small tracts and anterior root 6-11 tracts; the diameter number of nerve fibers in the three parts of spinal nerve dorsal root was (3 243±143) fibers per 100 μm2, including (1 702±85) Ia nerve fibers that constituted about 52.5% of the total nerve fibers. Ia nerve fibers were found to be evenly distributed in dorsal root and no gathering could be observed.CONCLUSION: The tracts in anterior and dorsal roots of spinal cord should be separated as minutely as possible during improved dorsal rhizotomy, which is beneficial for cutting off Ia nerve fibers correctly. Generally,the anterior root consists of 6-11 small tracts and dorsal roots of 10-18small tracts, and nerve tracts should not be cut off over 1/2 of total dorsal nerve fibers.