1、LOWER BACK PAIN AND HERNIA OF INTERVERTEBRAL DISC,腰痛和腰椎间盘突出症,Structural support and balance for upright posture,Functions of the Spine,Protection Spinal cord and nerve roots,Functions of the Spine,Internal organs,Flexibility of motion in six degrees of freedom,Functions of the Spine,Left and Right S
2、ide Bending,Flexion and Extension,Left and Right Rotation,Cranial - the head or towards the head Caudal - the tail or towards the tail Anterior - the front section or towards the front Posterior - the back section or towards the back Ventral - the front or anterior surface Dorsal - the back or poste
3、rior surface,Basic Terminology,Cranial,Caudal,Anterior,Posterior,Dorsal,Ventral,Vertebral Structures,Pedicle notches,Slight Notch,Deep Notch,Intervertebral Foramen,Intervertebral foramen,Nerve roots exit,Vertebral Structures,Body,Pedicle,Lamina,Superior Articular Process,Spinous Process,Transverse P
4、rocess,Vertebral Foramen,Lumbar Vertebrae,Body - L1 to L5 progressive increase in mass,Pedicles - longer and wider than thoracic; oval shaped,Spinous processes - horizontal, square shaped,Transverse processes - smaller than in thoracic region,Spinal foramen- large to allow for cauda equina and nerve
5、 roots,Intervertebral foramen - large, but with increased incidence of nerve root compression,Intervertebral Disc,Vertebral Structures,End Plate,Apophyseal Ring,Cartilaginous,Bony,The FUNCTIONAL UNIT of the spine Comprised of: Two adjacent vertebrae Intervertebral disc Connecting ligaments Two facet
6、 joints and capsules,The Motion Segment,Fibrocartilaginous joint of the motion segment Makes up the length of the spinal column Present at levels C2-C3 to L5-S1 Allows compressive, tensile, and rotational motion Largest avascular structures in the body,Intervertebral Disc,Intervertebral Disc,Annulus
7、 Fibrosus Outer portion of the disc,Lamellae,Great tensile strength,Made up of lamellae,Annulus Fibrosus,Layers of collagen fibers Arranged obliquely 30 Reversed contiguous layers,Intervertebral Disc,Nucleus Pulposus,Nucleus Pulposus,Inner structure Gelatinous High water content Resists axial forces
8、,Intervertebral Disc,Largest avascular structure Blood supply by diffusion through end plates Damage to the blood supply leads to degradation of the disc,Anatomy and Degenerative Change,The Vertebral Body (VB) Key Roles Carry 80% of the axial loads through VB and disc Endplates enable nutrition to d
9、iffuse to disc,Intervertebral Disc,The Intervertebral Disc,Has two roles Shock absorber of axial forces Pivot point in motion segment,Intervertebral Disc,Ligaments,Ligamentum flavum,Posterior longitudinal ligament,Anterior longitudinal ligament,Spinal Ligaments,Bands or sheets of tough, fibrous tiss
10、ue that connect bones, cartilage, or other structures Become active when stressed to maximum range of motion Protect the joints from being hyperflexed,The Intervertebral Disc and Degenerative Change,Two major components of IVD Annulus fibrosis: thick, fibrous “radial tire” Lamellae Nucleus pulposus:
11、 ball-like gel,The Intervertebral Disc (IVD) and Degenerative Change,By age 50, 95% of people show lumbar disc degeneration Not all have symptoms Significant changes to IVD are: Water and proteoglycan content decreases Collagen fibers of AF become distorted Tears may occur in the lamellae Results in
12、: Disc loses height and volume Loses resistance to loading forces No longer acts as a shock absorber,Overview - cont.,The motion segment is the functional unit of the spine and consists of Muscle (activators) Ligaments (passive restraints) Adjacent vertebral bodies A 3-joint complex of two facet joi
13、nts and a disc (pivots) Degeneration can begin in one or more of these joints, but ultimately all three will be affected,Degenerative Conditions,Provide an overview of degenerative conditions Degenerative Disease Spinal Stenosis Herniated Disc,Degenerative Disease - Overview,Loss of normal tissue st
14、ructure and function due to aging process Changes are usually gradual, trauma sometimes accelerates Degenerative changes do not always lead to clinical symptoms When changes cause symptoms (often pain), the process is referred to as osteoarthritis Spondylosis is degenerative changes in the spine,Ana
15、tomy and Degenerative Change,The Vertebral Body (VB) Degenerative Changes Sclerosis: Increased bone formation adjacent to endplates Reduces nutrition diffusing to disc Stiffens endplate, and reduces ability to absorb loads Osteophytes: Formation of small bony spurs Can project into neuro structures,
16、Facet Joints and Degenerative Change,Key Roles Carry 20% of compressive loads Help stabilize spine Degenerative Changes Cartilage lining loses water content Cartilage wears away Facets override each other Leads to abnormal function of motion segment,Anatomy and Degenerative Change,Ligaments and Musc
17、les Ligaments attach bone to bone Provide stability, enable normal motion Degenerative Changes Partial ruptures, necrosis and calcifications Negatively impact function of motion segment,Degenerative Disc Disease,Changes include: Disc loses height and volume Compressive loads transfer away from nucle
18、us to margins Sclerosis of endplate reduces disc nutrition Facet joints wear away cartilage, begin to override Motion segment becomes hypermobile Osteophytes develop to attempt to stabilize motion segment Osteophytes may encroach on neuro structures,Spinal Stenosis,Narrowing of the spinal canal and/
19、or lateral foramen through which the nerves travel Three types: Central stenosis: in central spinal canal where cord or cauda equina are located Lateral recess stenosis: in the tract where nerve roots exit canal Acquired: in lateral foramen where nerve roots exit to body Most frequent in lower cervi
20、cal and lower lumbar spine,Herniated Disc,Often called “ruptured disc” Very common pathology L3-4, L4-5, L5-S1 common locations Thought to be a culmination of acute traumatic events to the disc,Herniated Disc: 4 degrees,Nuclear herniation: nucleus ruptures. No disruption of outer annular fibersDisc
21、protrusion: ruptured nucleus causes outer fibers to bulgeNuclear extrusion: Complete split in annulus. Material leaks but remains attached to nucleus Sequestered nucleus: Leaked substance no longer attached to nucleus,INTRODUCTION,The back and leg pain since - Greeks recognized it. In the fifth cent
22、ury AD Aurelianus clearly described the symptoms of sciatica. The sciatica arose from either hidden causes or observable causes- a fall, a violent blow, pulling, or straining.,The most notable of these is the Lasgue sign, or straight-leg raising test, described by Forst in 1881 but attributed to Las
23、gue, his teacher.,This test was devised to distinguish hip disease from sciatica.,Biomechanics of the lumbar spine,Biomechanics of the lumbar spine,Biomechanics of the lumbar spine,Biomechanics of the lumbar spine,Biomechanics of the lumbar spine,Biomechanics of the lumbar spine,INTRODUCTION,Mixter
24、and Barr in their classic paper published in 1934 again attributed sciatica to lumbar disc herniation.,Definition,Ruptured discs are among the most common and painful of all back ailments. The condition occurs when the outer cover of a disc is torn and the soft inner tissue extrudes. The extrusion o
25、ften puts pressure on the spinal nerves, causing back and leg pain which can be severe. 腰椎间盘突出症是因椎间盘变性，纤维环破裂，髓核突出刺激或压迫神经根、马尾神经所表现的一种综合征。,Prolapsed intervertebral disc,It usually occurs in the L4/5 or L5/S1 intervertebral disc regions and is most often seen on only one side but may be bilateral. It m
26、ay occur in other regions, especially at the L3/4 level, and occasionally disc protrusion may occur at more than one level simultaneously. It is often due to degeneration of the disc and therefore occurs most commonly in middle or old age. Degeneration of the annulus fibrosus allows the nucleus pulp
27、osus to herniate through,压迫对神经根的作用,压迫改变神经根的传导、营养状态，通过影响局部血运和脑脊液的营养， 机械直接损伤神经内部，神经根受压变形，有张力，压迫神经根可引传导性损伤，功能改变。 同周围神经一样，单纯压迫不引起根痛，没有炎症和刺激因素压迫只产生感觉缺失，运动无力，反射异常，但无痛。如有化学炎症和代谢因素产生炎性反应存在,压迫对神经根的作用,压力从1013.33kPa引起了神经传导功能的逐渐减弱。其中，传入神经传导功能的减弱更加明显，而去压迫后，运动神经能更加容易和迅速地恢复到几乎正常的CMAP水平。 压迫在26.67kPa时，引起了神经传导功能的迅速减弱
28、，而且去压迫后传入神经几乎没有恢复，传出神经仍有30%40%的恢复。将压迫时间从2h延长到4h，对神经恢复能力的影响更加明显3。,产生腰痛的组织 -背根节,Howe发现背根节对中度压迫极度敏感，当压力解除后感觉神经释放的信号可持续25分钟。 从神经生理学角度背根节是特有的、“捣鬼”的疼痛源，突出椎间盘能挤压它 对于周围神经来说，当刺激解除后，神经冲动马上停止.,产生腰痛的组织-背根节,实验结果背根节在尼龙线牵拉产生60秒的发电，而玻璃棒压迫会产生4分钟的冲动,产生腰痛的组织-背根节,背根节的神经细胞与突触相交处的细胞膜上有高密度的钠通道，使其对机械压力特别敏感。 这种高密度的钠通道可能是导致神
29、经冲动持续，在背根节受压时产生生骨神经痛.,产生腰痛的组织-神经根,Olmarker等应用不同的化学标记物来研究压力的大小和压迫发生的速度与水肿形成和营养障碍的关系。 结果提示，压迫产生越迅速，神经根水肿的形成和营养供给障碍越明显。,产生腰痛的组织-脊神经背根,与DRG不同，背根对机械压力不是始终有反应，除非神经根有炎性或处可易惹状态。 Howe在被铬肠线结扎神经根后可以引出多次发电的情况，单一压迫刺激即可引A、d神经纤维放电5-30秒。 被刺激的神经根是有鞘神位由可能含有神经末梢。Jang发现了猫的S1背根中有点状直接受刺激区,产生腰痛的组织-脊神经背根,最有效的机械刺激是轻度牵拉，与临床情
30、况相吻合。 有病间盘水平的神经根比邻近正常的神经根更敏感 Kuslich在局麻下椎间盘手术中，对有炎症或压迫的神经根压迫特别敏感，压迫它再现坐骨神经痛 Smyth用尼龙线绕过受累神经根，轻拉即再现坐骨神经痛的,神经源的化学介质,损伤和炎症的组织释放的化学介质使神经末梢致敏。 这些神经致敏物质包括由C纤维释放出的P物质、11氨基酸神经肽。 P物质导致血管扩张，血浆外渗，肥大细胞释放组胺。 这些炎性介质的持续释放引起了疼痛。,神经源的化学介质,虽然原因还不清楚，P物质可能直接作用神经末梢或间接通过血管扩张，释放组胺、血浆外渗起作用。 P物质在神经致敏中起重要作用，这有重临床意义， 脊柱的运动正常是
31、无痛的，但在炎症条件下引起疼痛,腰痛症状持续的原因 非神经源的化学介质,在组织损伤中产生的可以激活和致敏神经末梢的化学介质包括：缓激肽、血清素(5-HT)、组织胺、钾离子、前列腺素。 已在椎小关节及邻近组织中发现了P物质， 使用10-g即能同时兴奋低痛阈和高痛阈神经纤维， 30分钟后这些神经对机械刺激的痛阈明显降低,非神经源的化学介质,当将角叉菱胶或陶土注入关节后，神经纤维致敏兴奋性增加，1-2mm的各方关节活动即可导致关节支配神经的持续释放冲动电位。 最近的研究表现在神经感受器对机械压力敏感的部位，注入角叉菱胶，会导致神经元放电达3小时,非神经源的化学介质,这些研究的临床意义：如果关节囊、韧
32、带、肌肉受牵拉，例如脊柱滑脱和椎间盘突出症，引起组织损伤会导致持久的伤害性刺激， 并可以导致一种循环状态，肌肉痉挛，痛觉过敏，以致持续性疼痛,椎间盘及神经根周围的炎症,有关椎间盘的神经生理学研究是有限的。 Cavanaugh报告了椎间盘受机械刺激时只偶有少量冲动，只有腹侧硬膜受牵拉才有持续冲动。 只有电刺激椎间盘和后纵韧带引起A-d纤维冲动，同椎管内注入致痛物质，像组胺作用一样,椎间盘及神经根周围的炎症,Yamashita报告了椎间盘对机械压力大部分情况是没有反应。椎间盘内只有静止伤害感受器，它只对损伤或炎症产生的致痛电学物质有反应。 McCarron向狗硬膜外腔注入自体的髓核，表现出它的致炎
33、作用。 Olmarker 发现身体髓核在神经 组织中产生炎性和退行性改变,免疫和炎症反应,腰腿痛当中，原因很复杂，椎间盘突出 的大小与疼痛程度不一， 生化和机械因素交互作用。 有很多证据表明髓核有致免疫原性，自体髓核与血液接触，对髓核自身抗体已发现，虽然很多证据表明介导免疫炎性，绝大多数以前的研究都注意到椎间盘退变和疼痛的产生中的免疫现象标志物。 Saal证明突出间盘边缘有免疫细胞，发现了T淋巴细胞IL-1、2，据细胞。浸润的不同程度分级与症状相关。反应程度与术前症状时间相关但病人没有全身的自身免疫性疾病表现, 疼痛直接原因不清。,磷脂酶A2 -PLA2,在风湿性关节炎、急性胰腺炎、血清单阴性
34、关节炎、脓毒症表现出明显的炎症作用。它在体内的源性： 表1 PLA2 activiyu PMN3,2Platelet1.4Plasma0.006Sperm28.0inflammatory synovial fluid 12.1herniated lumbar disc1212.0正常椎间盘内PLA2就有致水肿作用,PLA2的神经毒性,Steroid局部应用非常有效，在没有免疫反应的生化炎症，作为疼痛发生机制的另一个原因髓核有介导炎性的能力，含有高浓度的PLA2。 Saal在有腰痛病人病变节段的椎间盘组织内会有不正常高浓度的磷酸激酶A2-PLA2。髓核、PLA2及别的致炎物质作用到椎间盘的伤害感
35、觉受器，它激活痛感纤维的作用比单纯压力更大PLA2进入神经根后神经水肿，髓鞘轴突损伤，同注射蛇毒 PLA2，但作用程度轻，支持了PLA2的神经毒性硬腰外使用自体髓核，发生传导阻滞，神经周围组织炎症 。,Leakage of nucleus pulposus material to nerve roots, is a pathophysiologic mechanism in LBP and sciatica,Incision of the anulus fibrosus induces nerve root morphologic, vascular, and functional chang
36、es. An experimental study. Kayama -Japan: Spine 1996 The nerve conduction velocity was significantly lower in the incision group (13 14 m/sec) compared with the nonincision group (73 5 m/sec). The obvious signs of capillary stasis with an increased number and diameter of the intraneural capillaries
37、in the incision group.,Cultured, autologous nucleus pulposus cells induce functional changes in spinal nerve roots,Kayama -Sweden : Spine 1998 Nucleus pulposus cells and fibroblasts were cultured for 3 weeks, and various preparations were applied to the cauda equina in 29 pigs. After 1 week, nerve c
38、onduction velocity was determined by local electrical stimulation. Application of nucleus pulposus cells reproduced the previously seen reduction in nerve conduction velocity induced.,腰痛症状持续的原因 椎间盘及神经根周围的炎症,Kuslich在144例椎间盘手术中，在病变椎间盘外侧检查刺激或电刺激产生中度疼痛占70%，重度占30%。 突出椎间盘或狭窄的椎间只对DRG或突炎神经根的机械压迫是持续的，就能导致持续性
39、疼痛，或DRG或炎性神经根内压增加这种持续性疼痛就会变为进行性加重。 Cavanaugh将自体髓核注入DRG引起1-3分钟的神经释放,PLA2致痛原因,致炎因素；直接作用伤害感受器；磷脂酶本身的直接造成神经损伤。炎症介定导致源发性神经根坏死， 体外证实PLA2直接刺激纤维环伤害感受器。 这些化学物质可直接刺激纤维环和周围神细胞中的细小的无髓纤维C或Adeltal。致病物质作用后，伤害感受器的痛域下降。 （对机械刺激）正常的生理活动就可以导致腰痛、障碍痛、根性痛（在纤维环外1/3后纵韧带）.,第二部分：腰痛症状持续的原因 椎间盘及神经根周围的炎症,临床、组织化学、生理化学、神经组织学研究，髓核含
40、有化学性致炎、神经退变，急性期有神经兴奋的作用。 同样化学物质有氢离子、PLA2免疫球蛋白G等，在椎间盘性疼痛中，增加炎性神经根的敏感性起重要作用,Phospholipase A2 sensitivity of the dorsal root and dorsal root ganglion,Ozaktay USA ：Spine 1998 Jun Phospholipase A2 appeared to be neurotoxic when doses ranging from 100 to 400 U were applied on the mechanically sensitive se
41、gments of the dorsal root ganglia. PLA2 doses comparable to serum concentrations in human rheumatoid arthritis when applied to dorsal root ganglia. These results suggest that dorsal roots and dorsal root ganglion may be impaired by phospholipase A2, leading to sciatica and low back pain.,脊髓水平,中枢致敏 组
42、织损伤可能导致连续的神经冲动至脊髓，这使后角神经元致敏 致敏的神经元痛阈下降， 对传入冲动的反应增强， 对重复刺激的反应也增强， 接受刺激的阈值变宽。 恶性刺激导致中枢致敏时，有明确证据后角释放了兴奋性胺基酸和神经肽,脊髓水平-中枢致敏,在中枢致敏状态下， 机械刺激的致痛阈值已下降，使很低的机械刺激就可以让后角发出疼痛信号。 变宽的接受阈能把损伤处及附近正常组织的传入信号变为疼痛信号向上传递， 这就解释了腰疼痛位不清和持久、及牵涉痛的原因,脊髓水平-中枢致敏,Gilleffe发现了后角单个神经元可接受从各种脊柱组织传入的信号，呈一种高度会聚接收状态。 脊髓后角的神经元可以由压迫皮肤、椎小关节、
43、韧带、及肌肉而兴奋，这种高度会聚功能也是腰痛不易定位的原因,Chronic Compression of Dorsal Root Ganglion Produced by Intervertebral Foramen Stenosis,Hu SJ- Xian, PR China Pain 1998 Jul An experimental model in the rat. A small stainless steel rod (0.5-0.8 mm in diameter) was inserted into the L5 intervertebral foramen These neuro
44、ns had a greatly enhanced sensitivity to mechanical stimulation of the injured DRG and a prolonged after discharge. a persistent heat hyperalgesia 5-35 days The excitatory responses were evoked in the injured, but not the uninjured, DRG neurons.,EPIDEMIOLOGY-risk factors,Multiple factors affect the
45、development of back pain. smoking, pro-longed daily driving of motor vehicles, jobs requiring frequent repetitive lifting of heavy objects and twisting, the use of jackhammers and machine tools, and the operation of motor vehicles episodes of anxiety and depression. It is more common in males than f
46、emales and has a maximal incidence in the third and fourth decades of life.,LUMBAR DlSC HERNlATION,Back pain may be caused by stimulation of the pain fibers in the outer layers of the annulus fibrosus. Alternatively, distortion of the posterior longitudinal ligament, which is richly innervated by pa
47、in fibers, may result in back pain. Leg pain can result from compression of a nerve root by an HNP,腰痛可以起自于椎间盘、椎小关节、肌肉的神经末梢。 化学炎性介质释放，使正常无痛的运动变为疼痛性的。 髓核是强列的神经根和神经末梢致炎和刺激物质 椎间盘与神经根的位置、 DRG的特殊神经生理特点、神经根和DRG易被压迫而出现坐骨种经痛。 系列恶性冲动使后角感觉神经元致敏，导致的慢性疼痛状态,CIinicaI Presentation,The following are risk factors for
48、 herniated disc disease in the lumbar spine: smoking, pro-longed daily driving of motor vehicles, and frequent repetitive lifting of heavy objects and twisting. It is more common in males than females and has a maximal incidence in the third and fourth decades of life.,The clinician must rule out a
49、compressive lesion of the sciatic nerve peripherally before ascribing the pain to a herniated disc. There may be a history of a previous injury.,CIinicaI Presentation,A symptom- HNP. Sciatica is pain along the course of the sciatic nerve. The classic symptom is low back pain with radiation of severe pain down the back of the leg to the ankle and foot. It may be associated with neurological signs such as motor and sensory loss and occasionally bladder involvement.,
