皮内注药治疗疱疹后神经痛的机制

目的 在皮内注药治疗疱疹后神经痛（postherpetic neuralgia PHN)有效的基础上，通过动物实验探讨其疗效机制的神经学基础。方法 在家兔肩胛区皮内分别注射辣根过氧化物酶（HRP）和荧光素核黄（NY），用神经逆行追踪法研究皮内神经末梢到神经节神经细胞的上行轴浆流通道及初级神经元分布规律。结果 皮内注射HRP，NY分别在C4-T10脊神经节，颈，胸交感神经节，腹腔神经节，标记到神经细胞，脊神经节在C6-T8标记的细胞较多，交感神经节比脊神经节标记的细胞多，荧光标记神经细胞分布范围与HRP法基本一致或前后各多一个节段，而相同节段的标记神经细胞数明显比HRP标记的多。结论 动物实验从形态学上验证了皮内神经末梢到神经节神经细胞的上行轴浆流通道及初级神经元分布规律，皮内注药治疗PHN疗效可能与此通道有关。     

腰交感神经节射频热凝对糖尿病痛性周围神经病变大鼠的镇痛作用及对背根神经节TTX-R钠电流的影响

目的 评价射频热凝毁损腰交感神经节对糖尿病痛性周围神经病变大鼠的镇痛作用及对背根神经节（DRG）细胞上河豚毒素不敏感（TTX-R）钠通道电流的影响。方法 腹腔注射链尿佐菌素诱导大鼠糖尿病痛性周围神经病变模型，取造模成功的大鼠20只，随机分为糖尿病对照组（D组）及交感神经节射频热凝组（R组），每组10只，另取10只同月龄大鼠为正常对照组（C组），R组大鼠行右侧L3，4椎旁射频热凝毁损腰交感神经节。于射频热凝前、射频热凝后1、2周采用von Frey纤维丝测定缩爪反应阈值（PWT）;射频热凝后2周，急性分离小DRG细胞，采用全细胞膜片钳记录方法，在电压钳制下记录TTX-R钠通道电流。结果 与C组比较，射频热凝前D组和R组PWT降低（P〈0．01），射频热凝后1、2周，R组PWT低于C组（P〈0．05），高于D组（P〈0．05）;射频热凝后2周，与C组比较， D组、R组I-V曲线向左移，R组电流密度高于C组（P〈0．01），低于D组（P〈0．05），与C组比较，D组、R组半激活电压及半失活电压升高（P〈0．01），D组和R组之间差异无统计学意义（P〉0．05）。结论 腰交感神经节射频热凝可有效缓解糖尿病痛性周围神经病变大鼠的痛觉过敏，抑制小DRG细胞TTX-R钠通道电流可能是其发挥镇痛作用机制之一。     

高应力与腰椎小关节方向变化关系的实验研究

目的:观察兔腰椎小关节加载应力后小关节方向的变化,并探讨小关节在应力作用下方向变化的机制.方法:将42只6月龄新西兰白兔随机分为正常对照组(A组)、椎间盘退变组(B组)、小关节加载组(C组)及椎间盘退变联合小关节加载组(D组),A组6只,其他3组各12只.对B组和D组动物采用针刺抽吸髓核法建立L3/4、L5/6椎间盘退变模型,对A组和C组仅剥离椎旁肌.建模6周后分别对C组和D组的L3/4、L5/6小关节加载拉簧造成高应力模型,对A组和B组仅行小关节暴露,分别于小关节术后4个月、8个月获取腰椎,进行MicroCT扫描,观察小关节形态,B、C、D组在横断面上测量L3/4、L5/6小关节角度(关节突关节面与椎体正中矢状面的夹角)并将两个节段数据合并分析,A组测量L3/4 、L4/5、L5/6、L6/7小关节角度并将数据合并分析,小关节角度越小,小关节方向越偏向矢状位.结果:组内比较,各组8个月时小关节方向较4个月时更加矢状化(均P＜0.05);同一时间点,D组的小关节方向较B组更加矢状化,C组的小关节方向较A组更加矢状化,差异均有显著性意义(均P＜0.05),A、B组间及C、D组间比较小关节角度无显著性差异(P＞0.05).小关节加载组(C组和D组)的小关节较小关节未加载组(B组)退变严重,时间越长退变越严重;各时间点A组小关节结构清晰.结论:高应力可引起兔腰椎小关节退变,小关节方向的矢状化改变是由小关节退变和重塑所导致.     

下颈椎经关节螺钉固定“两点法”置钉的解剖学研究

目的通过解剖学研究,获得下颈椎经关节螺钉的安全置钉方法。方法取18具颈椎标本,仔细解剖颈部的后方和前侧方,以清楚地暴露颈椎侧块,保护好脊神经前、后支（C2～8）及与周围结构的关系。确定安全进、出钉：以侧块背面中心点内侧1mm为进钉点;下位椎体上关节突的侧前方,横突与关节突相交处为出钉点。从C2/C3～C5/C6直视下通过以上2点置入克氏针,通过正侧位X线片测量克氏针在矢状面上的尾倾角、在冠状面上的外倾角及进钉深度,以确定经关节螺钉固定的进钉角度和螺钉长度,并测量经关节螺钉出钉点与脊神经前、后支和椎动脉的距离。结果实验中所有克氏针均成功置入。经关节螺钉的外倾角度为16.5°±5.1°,尾倾角度为36.6°±5.1°,钉道长度为19.0mm±1.2mm。经关节螺钉的外倾角度和尾倾角度在各节段间略有不同,但差异均无统计学意义（P〉0.05）,但钉道长度在C2/C3与C3/C4/C5/C6间差异有统计学意义（P〈0.05）。经关节螺钉出钉点与脊神经前支距离为18.2mm±2.3mm,与后支距离为7.3mm±1.4mm,与椎动脉距离为5.8mm±1.5mm,在各节段间略有不同,但差异均无统计学意义（P〉0.05）。结论使用下颈椎经关节螺钉固定技术时建议以侧块背侧中心点内侧1mm为进钉点,在矢状面上尾倾35°～40°,在冠状面上外倾15°～20°,尽量将螺钉从下位椎体上关节突的侧前方、横突后嵴与关节突连接处出钉。     

下颈椎经关节螺钉固定“两点法”置钉的解剖学研究

【摘要】 目的 通过解剖学研究,获得下颈椎经关节螺钉的安全置钉方法。 方法 取18具颈椎标本,仔细解剖颈部的后方和前侧方,以清楚地暴露颈椎侧块,保护好脊神经前、后支（C2~8）及与周围结构的关系。确定安全进、出钉：以侧块背面中心点内侧1 mm为进钉点;下位椎体上关节突的侧前方,横突与关节突相交处为出钉点。从C2/C3~C5/C6直视下通过以上2点置入克氏针,通过正侧位X线片测量克氏针在矢状面上的尾倾角、在冠状面上的外倾角及进钉深度,以确定经关节螺钉固定的进钉角度和螺钉长度,并测量经关节螺钉出钉点与脊神经前、后支和椎动脉的距离。 结果 实验中所有克氏针均成功置入。经关节螺钉的外倾角度为16.5°±5.1°,尾倾角度为36.6°±5.1°,钉道长度为19.0 mm±1.2 mm。经关节螺钉的外倾角度和尾倾角度在各节段间略有不同,但差异均无统计学意义（P＞0.05）,但钉道长度在C2/C3与C3/C4 /C5 /C6 间差异有统计学意义（P＜0.05）。经关节螺钉出钉点与脊神经前支距离为18.2 mm±2.3 mm,与后支距离为7.3 mm±1.4 mm,与椎动脉距离为5.8 mm±1.5 mm,在各节段间略有不同,但差异均无统计学意义（P＞0.05）。 结论 使用下颈椎经关节螺钉固定技术时建议以侧块背侧中心点内侧1 mm为进钉点,在矢状面上尾倾35°~40°,在冠状面上外倾15°~20°,尽量将螺钉从下位椎体上关节突的侧前方、横突后嵴与关节突连接处出钉。     

颈椎间盘与后纵韧带上交感神经分布的特点及临床意义

目的观察颈椎间盘及后纵韧带上交感神经分布特点及其临床意义。方法按节段（C2／3、C3／4、C4／5、C5／6、C6／7）分别切取16只兔颈椎间盘及颈椎后纵韧带，其中8只通过NF200对其神经纤维进行荧光组织化学染色，另8只通过冰冻切片．乙醛酸（SPG）法对交感神经纤维进行染色，通过荧光显微镜观察及图像分析软件（Image—pro plus 5．0软件）描述分析其分布特点。结果在颈椎间盘纤维环外环分布有少量交感神经节后纤维。在颈椎后纵韧带上分布有大量交感神经节后纤维，主要呈网状分布，且以椎间盘区分布相对密集。分布于后纵韧带浅层的交感神经较深层密集，分布于C2／3、C3／4、C4／5的交感神经较C5／6、C6／7密集。结论颈椎间盘及后纵韧带上分布的交感神经可能是引发颈性眩晕的另一重要因素。     

屈曲暴力致颈椎小关节脱位动物模型的建立

目的：建立颈椎小关节脱位的动物模型，探讨屈曲撞击暴力作用下，颈椎关节突关节的稳定因素。方法：26只犬按照手术预处理不同分为3组，A组：6只．切断犬C5～C6间棘上韧带和棘间韧带；B组：10只，在A组处理方式的基础上破坏犬C5～C6间关节突关节的关节囊及黄韧带；C组：10只．在B组的基础上切断C5～C6间前纵韧带。以BIM—Ⅱ型撞击机在同样致伤条件下对这3组动物进行撞击实验：实验结果通过影像学检查和行为学观察评价结果：A组动物均未发生小关节突关节脱位。B组有5例发生小关节脱位：C组有9例发生小关节脱位。结论：关节突关节的关节囊、黄韧带和前纵韧带是维持颈椎关节突关节稳定性的重要结构。     

三种下颈椎经关节螺钉植入方法的比较研究

目的：比较3种下颈椎经关节螺钉植入方法的优缺点,为选择下颈椎经关节螺钉的植入方法提供可靠的基础资料。方法：选用新鲜颈椎标本（C1-T1）24具（男14具,女10具）,年龄55～80岁,平均68岁。采用抽签随机对照研究方法,在每一颈椎标本两侧用不同的植入方法植入下颈椎经关节螺钉。根据进钉点及进钉方向的不同,采用Takayasu法（A组）、Dalcanto法（B组）、Klekamp法（C组）作为下颈椎经关节螺钉的植入方法。Takayasu法选用侧块中线上中1/3交界处作为进钉点,螺钉向前侧、尾侧倾斜,与侧块冠状面呈60°～80°,平行于矢状面作为进钉方向;Dal-canto法采用进钉点在侧块中点下方2mm,方向向尾侧倾斜40°,向外侧倾斜20°;Klekamp则将侧块中点内下方1mm为进钉点,方向向尾侧倾斜40°,向外侧倾斜20°。对A、B、C组分别统计植入时关节突关节劈裂、植入后椎动脉侵犯、神经根前后支损伤和螺钉通过关节突关节的情况。结果：24具颈椎标本共48侧,植入下颈椎经关节突螺钉192枚,其中A、B、C组各64枚。A组未见下关节突劈裂;B组见下关节突下缘劈裂17例,外缘劈裂8例;C组下关节突下缘劈裂1例,外缘劈裂1例。3组均未见上关节突劈裂。3组螺钉植入时关节突关节劈裂情况比较,B组下关节突劈裂最多,与其他2组差异有统计学意义（χ2AB=31.07,P〈0.01;χ2BC=24.83,P〈0.01）。C组2例下关节突劈裂,与A组比较差异无统计学意义（χ2AC=2.03,P〉0.05）。A组36枚螺钉侵犯椎动脉,B、C组均未见椎动脉侵犯。3组螺钉植入后椎动脉受累情况,A组高于其他2组（χ2AB=50.09,P〈0.01;χ2AC=50.09,P〈0.01）。神经根前支损伤A组40例,B组5例,C组3例;神经根后支损伤A组16例,B组18例;C组14例。3组间颈神经根前支受累比较,A组高于其他2组（χ2AB=41.98,P〈0.01;χ2AC=47.94,P〈0.01）,而B、C组差异无统计学意义。颈神经根后支受累比较,3组间差异无统计学意义（χ2AB=0.16,P〉0.05;χ2AC=0.17,P〉0.05;χ2BC=0.67,P〉0.05）。A组5例未经过关节突关节,B、C2组均经过关节突关节,3组间差异无统计学意义（χ2AB=3.33,P〉0.05;χ2AC=3.33,P〉0.05）。结论：Takayasu法在螺钉植入过长时易引起神经根和椎动脉损伤,而Dalcanto法在植入螺钉时易引起下关节突的劈裂。相比较而言,Klekamp法临床上更值得推崇。     

关节内注射复方倍他米松对兔佐剂性关节炎的效果

目的评价关节内注射复方倍他米松对兔佐剂性关节炎的效果。方法日本大耳白兔，雌雄各半，体重2～3kg，6～8月龄。采用皮内注射卵清蛋白＋非完全弗氏佐剂的方法制备佐剂性关节炎模型。佐剂性关节炎模型制备成功的48只免随机分为2组（n=24），C组双膝关节内各注射生理盐水1ml；D组注射复方倍他米松0．5mg／kg。每组各随机取6只兔，持续观察膝关节外观，分别于治疗前、治疗后2周测量髌骨上缘处双膝周径，并测定膝关节灌洗液中一氧化氮（NO）浓度，治疗后2周处死兔，打开膝关节，观察关节腔内改变，取髌上囊处滑膜，光镜下观察病理学改变。2组分别于治疗后1、2、3d各随机处死6只兔，取髌上囊滑膜，观察细胞凋亡情况。结果与c组比较，治疗后D组关节滑膜炎性反应较轻，NO浓度降低（P〈0．01）；治疗后2、3d滑膜细胞凋亡率升高（P〈0．05或0．01）。结论膝关节内注射复方倍他米松0．5mg／kg对免佐剂性关节炎有抗炎作用，可能与抑制NO的合成及促进滑膜细胞凋亡有关。     

下颈椎关节突关节与椎体后缘关系的影像学研究

目的：研究探讨下颈椎关节突关节前缘与椎体后缘的位置关系，为临床行下颈椎经关节螺钉植入时评价进钉深度提供参考。方法：选取无明显下颈椎畸形的标准颈椎侧位X线片100张，下颈椎标准CT平扫片50张，测量下颈椎关节突关节顶点、中部、基底部前缘与椎体后缘的距离（分别记为HS，HM，HI），椎体后缘之前为负、之后为正。并对测量数据行统计学分析。结果：所有关节突关节前缘距离、椎体后缘的距离从顶点到基底部逐渐减小（HS〉HM〉HI）。C。关节突关节前缘大多位于椎体后缘之前（HS，HM，HI均为负值）；C4.5C5.6关节突关节前缘逐渐后移；Co，，关节突关节前缘均位于椎体后缘之后（HS，HM，HI均为正值）。下颈椎关节突关节顶点前缘与椎体后缘的距离HS从C。到C6，7逐渐增大，C3．4为（0±0．25）mm，C4．5为（2．03±0．47）mm，C5．6为（2．45±0．56）mm，C6．7为（2．91±1．05）mm；下颈椎关节突关节中部前缘与椎体后缘的距离HM从C3.4到C6.7逐渐增大，C3.4为（-1．57±0.53）mm,C4.5为（O．50±0．26）mm，C5．6为（0．56±0．36）mm，C6．7为（1．54±0．39）mm；下颈椎关节突关节基底部前缘与椎体后缘的距离HI从C3.4到C6.7逐渐增大，C3.4为（-2．03±0．40）mm，C4．5为（0±0．30）mm，C5，6为（0．50±0．44）mm，C6．7为（1．08±0．70）mm。结论：在行下颈椎经关节螺钉固定时，螺钉的头部在C3.4应位于相应榷体后缘前方0～2mm，C4.5应位于相应椎体后缘之后0-2mm，C5.6应位于相应椎体后缘之后0．5-2．5him，C6.7应位于相应椎体后缘之后1～3mm。下颈椎关节突关节前缘与椎体后缘关系的确立，可为临床工作中下颈椎经关节螺钉植入时判断进钉深度提供参考。     

Sensory and sympathetic innervation of cervical facet joint in rats

Objective:To explore the patterns of innervation of cervical facet joints and determine the pathways from facet joints to dorsal root ganglions (DRGs) in order to clarify the causes of diffuse neck pain, headache, and shoulder pain. Methods:Forty-two male Sprague-Dawley rats, weighing 250-300 g, were randomly divided into three groups:Group A (n = 18) , Group B (n = 18) , and Group C (n = 6). Under anesthesia with intraperitoneal pentobarbital sodium (45 mg/kg body weight) , a midline dorsal longitudinal incision was made over the cervical spine to expose the left cervical facet joint capsule of all the rats under a microscope. The rats in Group A underwent sympathectomy, but the rats in Group B and Group C did not undergo sympathectomy. Then 0.6μl 5% bisbenzimide (Bb) were injected into the C1-2,C3-4 and C5-6 facet joints of 6 rats respectively in Group A and Group B. The holes were immediately sealed with mineral wax to prevent leakage of Bb and the fascia and skin were closed. But in Group C,0.9% normal saline was injected into the corresponding joint capsules. Then under deep reanesthesia with intraperitoneal pentobarbital sodium (45 mg/kg body weight), C1-C8 left DRGs in all rats and the sympathetic ganglions in Group B were obtained and the number of the labeled neurons was determined. Results:Neurons labeled with Bb were present in C1-C8 DRGs in both Group A and Group B, and sympathetic ganglions in Group B. In the C1-2 and C3-4 subgroups, labeled neurons were present from C1 to C8 DRGs, while in C5-6 subgroups they were from C3 to C8. The number of Bb ( ) neurons after sympathectomy was not significantly different in the injected level from that without sympathectomy. But in the other levels,the number of Bb ( ) neurons after sympathectomy was significantly less than that without sympathectomy. Conclusions:The innervation of the cervical facet joints is derived from both sensory and sympathetic nervous system, and DRGs are associated with sympathetic ganglions through nerve fibers outside the central nerve system.     

Sensory innervation of the cervical facet joints in rats

STUDY DESIGN: With a retrograde neurotracing method with Fluoro-Gold (FG; Fluorochrome, Denver, CO), the level of dorsal root ganglions (DRGs) innervating the C1-C2, C3-C4, and C5-C6 facet joints and their pathways were investigated in rats. OBJECTIVES: To clarify the levels of DRGs and parasympathetic nodose ganglions innervating the cervical facet joints and to determine the pathways from the facet joint to DRGs. SUMMARY OF BACKGROUND DATA: Patients with cervical facet lesions and whiplash sometimes experience diffuse neck pain, headache, arm, and shoulder pain, but the pattern of sensory innervation of the facet joint is still unclear. METHODS: Sixty male Sprague-Dawley rats were used. Fluoro-gold crystals (FG) were applied into the C1-C2 (C1-C2 group), C3-C4 (C3-C4 group) and C5-C6 (C5-C6 group) facet joints, and numbers of the labeled neurons in DRGs from C1 to T5 and nodose ganglions were determined. To determine the sensory pathway, bilateral sympathectomy was performed. RESULTS: Neurons labeled with FG were present in the DRGs from C1 through C8 in the C1-C2 group, from C1 to T2 in the C3-C4 group, and from C3 to T3 in the C5-C6 group without sympathectomy. In the nodose ganglions, 17 FG-labeled neurons were present. The number of the labeled neurons after sympathectomy was not significantly different in the C1, C2, and C3 DRGs in the C1-C2 group, in the C3 and C4 DRGs in the C3-C4 group, and in the C5 and C6 DRGs in the C5-C6 group from that in the groups without sympathectomy. In contrast, the number of labeled neurons in the DRGs was significantly less at the other levels than that in the groups without sympathectomy (P < 0.01). CONCLUSION: Sensory nerve fibers of the cervical facet joint were derived from the C1-T3 DRGs. Some sensory nerves from the cervical facet joint entered the paravertebral sympathetic trunks and reached the DRGs at multisegmental levels. The present findings regarding the multisegmental innervation to the facet joint may be of importance in the treatment of facet joint syndrome.     

Sensory innervation of the dorsal portion of the lumbar intervertebral discs in rats

STUDY DESIGN: The levels of dorsal root ganglions (DRGs) innervating the dorsal portion of the lumbar intervertebral discs from L1-L2 to L4-L5 were investigated in rats by the retrograde transport method. The pathways and functions of nerve fibers supplying the dorsal portion of the discs were investigated by denervation and immuno-histochemistry. OBJECTIVES: To investigate the sensory innervation of the dorsal portion of the lumbar intervertebral discs in rats. SUMMARY OF BACKGROUND DATA: The dorsal portion of the L5-L6 disc has been reported to be innervated multisegmentally, and anesthetic blockade of the paravertebral sympathetic trunks and the L2 spinal nerve can relieve discogenic low back pain. However, sensory innervation of the dorsal portion of the lumbar discs at other levels has not been clarified. METHODS: A retrograde transport of Fluoro-Gold was used. We studied a nonsympathectomy group (n = 44) and a sympathectomy group (n = 50) in which paravertebral sympathetic trunks were resected from L1 to L5 levels. Using a ventral approach, Fluoro-Gold crystals were inserted into the dorsal portion of the L1-L2, L2-L3, L3-L4, and L4-L5 discs. Seven days after surgery, Fluoro-Gold-labeled neurons were counted in the bilateral dorsal root ganglions from T10 to L6. RESULTS: Fluoro-Gold-labeled neurons were distributed in dorsal root ganglions from T11 to L5 levels in the nonsympathectomy group. However, in the sympathectomy group the number of labeled neurons was less than that of the nonsympathectomy group in T11, T12, and T13 dorsal root ganglions of the L1-L2 disc group, in T12, T13, and L1 dorsal root ganglions of the L2-L3 disc group, in T12, T13, L1, and L2 dorsal root ganglions of the L3-L4 disc group, and in T12, T13, L1, and L2 dorsal root ganglions of the L4-L5 disc group. CONCLUSION: The dorsal portion of the lumbar discs from L1-L2 to L4-L5 is multisegmentally innervated by the T11 through L5 dorsal root ganglions. Sensory fibers from the upper dorsal root ganglions innervate the dorsal portion of the discs via the paravertebral sympathetic trunks, although those from the lower dorsal root ganglions innervate via the sinuvertebral nerves. Furthermore, sensory nerve fibers enter the paravertebral sympathetic trunks through the corresponding ramus communicans and reach the dorsal root ganglions via each ramus communicans at the L2 and/or more cranial levels.     

Up-regulation of p55 TNF alpha-receptor in dorsal root ganglia neurons following lumbar facet joint injury in rats

The rat L5/6 facet joint is multisegmentally innervated from the L1 to L6 dorsal root ganglia (DRG). Tumor necrosis factor (TNF) is a known mediator of inflammation. It has been reported that satellite cells are activated, produce TNF and surround DRG neurons innervating L5/6 facet joints after facet injury. In the current study, changes in TNF receptor (p55) expression in DRG neurons innervating the L5/6 facet joint following facet joint injury were investigated in rats using a retrograde neurotransport method followed by immunohistochemistry. Twenty rats were used for this study. Two crystals of Fluorogold (FG; neurotracer) were applied into the L5/6 facet joint. Seven days after surgery, the dorsal portion of the capsule was cut in the injured group (injured group n = 10). No injury was performed in the non-injured group (n = 10). Fourteen days after the first application of FG, bilateral DRGs from T13 to L6 levels were resected and sectioned. They were subsequently processed for p55 immunohistochemistry. The number of FG labeled neurons and number of FG labeled p55-immunoreactive (IR) neurons were counted. FG labeled DRG neurons innervating the L5/6 facet joint were distributed from ipsilateral L1 to L6 levels. Of FG labeled neurons, the ratio of DRG neurons immunoreactive for p55 in the injured group (50%) was significantly higher than that in the non-injured group (13%). The ratio of p55-IR neurons of FG labeled DRG neurons was significantly higher in total L1 and L2 DRGs than that in total L3, 4, 5 and 6 DRGs in the injured group (L1 and 2 DRG, 67%; L3, 4, 5 and 6 DRG, 37%, percentages of the total number of p55-IR neurons at L1 and L2 level or L3–6 level/the total number of FG-labeled neurons at L1 and L2 level or L3–6 level). These data suggest that up-regulation of p55 in DRG neurons may be involved in the sensory transmission from facet joint injury. Regulation of p55 in DRG neurons innervating the facet joint was different between upper DRG innervated via the paravertebral sympathetic trunks and lower DRG innervated via other direct routes. Y. Sakuma and S. Ohtori contributed equally to this work.     

Characteristics of sensory DRG neurons innervating the lumbar facet joints in rats

The rat L5/6 facet joint, from which low-back pain can originate, is multisegmentally innervated from the L1 to L5 dorsal root ganglions (DRGs). Sensory fibers from the L1 and L2 DRGs are reported to non-segmentally innervate the paravertebral sympathetic trunks, whilst those from the L3 to L5 DRGs segmentally innervate the L5/6 facet joint. In the current study, characteristics of sensory DRG neurons innervating the L5/6 facet joint were investigated in rats, using a retrograde neurotransport method, lectin affinity- and immuno-histochemistry. We used four markers: (1) calcitonin gene-related peptide (CGRP) as a marker of small peptide containing neurons, (2) the glycoprotein binding the isolectin from Griffonia simplicifolia (IB4) or (3 the purinergic P2X₃ receptor for small, non-peptide containing neurons, and (4) neurofilament 200 (NF200) for small and large myelinated fibers. IB4-binding and CGRP and P2X₃ receptor containing neurons are typically involved in pain sensation, whereas NF200 is associated with pain and proprioception. Neurons innervating the L5/6 facet joints, retrogradely-labeled with fluoro-gold (FG), were distributed throughout DRGs from L1 to L5. Of FG-labeled neurons, the ratios of NF200 immunoreactive (IR) neurons and CGRP-IR neurons were 37% and 35% respectively. The ratio of IB4-binding and P2X₃ receptor-IR neurons was 10%, significantly less than the ratio of CGRP-IR neurons to FG-labeled neurons. The ratios of IB4-binding and P2X₃ receptor-IR neurons were significantly higher, and that of CGRP-IR neurons was significantly less in L1 and L2 DRGs than those in L3, L4 or L5 DRGs. Under physiological conditions in rats, DRG neurons transmit several types of sensations, such as proprioception or nociception of the facet joint. Most neurons transmitting pain are CGRP-IR peptide-containing neurons. They may have a more significant role in pain sensation in the facets via peptidergic DRG neurons.Tetsuhiro Ishikawa, Masayuki Miyagi, and Seiji Ohtori contributed equally to this work.     

Calcitonin gene-related peptide immunoreactive DRG neurons innervating the cervical facet joints show phenotypic switch in cervical facet injury in rats

Patients with cervical facet lesions and facet joint injury sometimes experience diffuse neck pain, headache, and arm and shoulder pain. However, the pathophysiology of the intensity and expansion of facet joint pain has not yet been investigated. Retrograde transport of fluoro-gold (F-G) and immunohistochemistry of calcitonin gene-related peptide (CGRP) was used in 20 rats (control group, n=10; injured group, n=10). For the injured group, the whole facet capsule was incised. Of the total F-G labelled dorsal root ganglion (DRG) neurons innervating the C5/6 facet joint, the number and the cross-sectional area of cell profiles of F-G labelled CGRP-ir neurons were evaluated in the bilateral DRGs of both groups. The numbers of CGRP-ir F-G labelled DRG neurons as a percentage of all F-G labelled DRG neurons at C3, C4, C5, C6, C7, C8, T1, T2, and T3 respectively were 30, 22, 43, 47, 21, 19, 25, 36 and 30% in the control group, and 13, 15, 23, 17, 15, 8, 16, 28 and 35% in the injured group, with the injured group showing a significantly lower percentage of CGRP-ir F-G labelled neurons than the control group at C5 and C6 (P<0.05). However, the mean cross-sectional area of F-G labelled CGRP-ir cells from C3 to C8 DRGs increased from 625+/-22 micro m(2) to 878+/-33 micro m(2) in the injured group (P<0.001). Associated with the injured facet joints, the phenotypic switch to large neurons may complicate the mechanism of injured facet pain.     

Distribution of A-delta and C-fiber receptors in the cervical facet joint capsule and their response to stretch

BACKGROUND: It has been proposed that cervical facet joint capsules are a major source of whiplash pain. However, there is a paucity of neurophysiologic data to support this hypothesis. The purposes of this study were to determine the distribution of A-delta and C-fiber sensory receptors in the facet joint capsule and to test their patterns of response to stretch and related sensory function. METHODS: Laminectomy from C4 to C7 was performed in seventeen goats, while they were under general anesthesia, to expose the C6 nerve roots. Customized dual bipolar electrodes were used to record neural activity from one of the C6 branches. An 8 or 15-V electrical stimulus was used to provoke receptor activity in nine designated areas on the dorsal part of the C5-C6 facet joint capsule. Receptors were classified on the basis of conduction velocities. The waveform of an identified receptor was set up as a template to determine its neural activity in response to capsular stretch. The characteristics of each single receptor's response to capsular stretch were analyzed to determine its sensory function as a mechanoreceptor or nociceptor. RESULTS: Two hundred and forty-eight receptors on the dorsal part of the C5-C6 facet joint capsule were evoked by electrical stimulation in the seventeen goats. More C-fiber receptors were found on the dorsolateral aspect of the facet joint capsule, where tendons and muscles were attached. The response to stretch of 120 receptors, from twelve goats, were analyzed to classify them into one of four categories (high-threshold mechanoreceptors, non-saturated low-threshold mechanoreceptors, saturated low-threshold mechanoreceptors, and silent receptors) or as unclassified receptors. CONCLUSIONS: The existence of receptors in the facet joint capsule indicates that the capsule has pain and proprioceptive sensory functions.     

Sensory innervation of the sacroiliac joint in rats

STUDY DESIGN: The segmental levels of dorsal root ganglions innervating the sacroiliac joint in rats were investigated using the retrograde transport method. The pathways and functions of the nerve fibers supplying the sacroiliac joint were determined by immunohistochemical detection of transported tracer. OBJECTIVES: To study the sensory innervation of the sacroiliac joint and to elucidate the neural pathways of low back pain originating from the sacroiliac joint. SUMMARY OF BACKGROUND DATA: The sacroiliac joint is a possible source of low back pain. The L4-S4 spinal nerves have been regarded as the nerves innervating the sacroiliac joint in humans. However, the origins of nerve fibers have not been analyzed experimentally with tracer methods. METHODS: Cholera toxin B subunit, a neural tracer, was injected into the left sacroiliac joint of adult rats, and the bilateral dorsal root ganglions were immunohistochemically examined 4 days after injection. In another rat group, the dorsal root ganglions were examined using the same methods after resection of the left sympathetic trunk from L2 to the most caudal level. Thus, the pathways of the nerve fibers supplying the sacroiliac joint were investigated. RESULTS: Labeled neurons were mainly located in the ipsilateral dorsal root ganglions from L1 to S2 of the unsympathectomized rats and in the ipsilateral dorsal root ganglions from L4 to S2 of the sympathectomized rats. CONCLUSIONS: The sacroiliac joint was innervated by sensory neurons in dorsal root ganglions ipsilateral to the joint from L1 to S2. Sensory fibers from the L1 and L2 dorsal root ganglions passed through the paravertebral sympathetic trunk.     

Degenerative changes of the cervical facet joints in the medial and lateral atlantoaxial joint - a paleopathological study

AIM: This article describes the prevalence of degenerative changes of the upper cervical spine (C1-C2) and cervical facet joints found during investigations of spinal column remains. MATERIALS AND METHODS: This study was conducted on a sample of 196 cervical spines from southwestern Germany which derive from the 6th to 8th centuries AD. The degenerative lesions were classified into grades 1 (marginal osteophytes), 2 (uneven joint surfaces), or 3 (osseous ankylosis). RESULTS: Of the skeletons examined, 19.4 % (n = 38) showed degenerative changes of the cervical facet joints and/or upper cervical spine (mean age at death was 44 years). The medial (6.1 %) and lateral (0.6 %) atlanto-axial joints were rarely involved in degenerative changes. The facet joints from C3-C4 to C6-C7 showed degenerative changes in 8.0-11.7 % of cases (usually grade 1 and 2). The C2-C3 facet joints were significantly involved in degenerative changes in 19.7 % of cases, one fourth of which were osseous ankylosis (grade 3). CONCLUSION: The C2-C3 facet joints showed a high rate of degenerative changes.     

Primary sensory neurons with dichotomizing axons projecting to the facet joint and the sciatic nerve in rats.

STUDY DESIGN: Dorsal root ganglion (DRG) neurons that have dichotomizing axons to the lumbar facet joint and to the sciatic nerve were investigated in rats using a double fluorescent labeling technique. OBJECTIVES: To clarify the existence of DRG neurons with dichotomizing axons projecting to the lumbar facet joint and to the sciatic nerve in rats. SUMMARY OF BACKGROUND DATA: DRG neurons having dichotomizing axons have been reported in several species and are considered to be related to referred pain. However, such DRG neurons have not been investigated in the lumbar spine. Clinically, pain from the lumbar facet joint is sometimes referred to the lower extremities innervated by the sciatic nerve. METHODS: Two kinds of neurotracers (DiI and FG) were used in the present double-labeling study. DiI crystals were placed in the left L5-L6 facet joint, and FG was applied to the ipsilateral sciatic nerve or along the midline of the L5 dermatome. Bilateral DRGs T13-S1 were observed by fluorescence microscope. RESULTS: DRG neurons double labeled with DiI and FG were recognized only in the ipsilateral DRGs from L3 to L6 levels. Approximately 3% of DRG neurons innervating the L5-L6 facet joint had other axons to the sciatic nerve. By contrast, no double-labeled neurons were observed after FG was applied to the L5 dermatome. CONCLUSIONS: In rats approximately 3% of DRG neurons innervating the lumbar facet joints have dichotomized axons projecting to the sciatic nerve.