Lumbar sympathectomy increases blood flow in a dog model of chronic cauda equina compression

OBJECTIVE: This study was designed to assess changes in blood flow of the dog cauda equina after lumbar sympathectomy using an experimental chronic cauda compression model. METHODS: The cauda equina was compressed at 10 mm Hg with a plastic balloon in all animals (n = 12). One week later, bilateral lumbar sympathectomy was carried out in the LSX group (n = 7), and vessels of the cauda equina were thereafter observed for 90 minutes using a specially designed microscope supplied with a video camera. Five animals did not undergo sympathectomy and were used as controls. The volume of blood flow was calculated from two parameters: velocity (mm/s) and diameter (microm) of a vessel observed in each animal. RESULTS: The increment in vessel diameter in the LSX group was pronounced at 30 and 45 minutes after sympathectomy compared with the control group (P < 0.05). Blood flow in the LSX group was increased at 30 minutes depending on dilation of the vessel diameter compared with the control group (P < 0.05). The velocity in the observed vessels remained unchanged throughout the measurements. CONCLUSIONS: These data suggest that lumbar sympathectomy could induce an increase in blood flow of the compressed cauda equina. As lumbar sympathetic block increases blood flow not only in the lower limbs but also in the cauda equina, it might be evaluated for a conservative treatment of intermittent claudication due to lumbar spinal canal stenosis.     

Vasodilative effects of prostaglandin E<Subscript>1</Subscript> derivate on arteries of nerve roots in a canine model of a chronically compressed cauda equina

Background  

Reduction of blood flow is important in the induction of neurogenic intermittent claudication (NIC) in lumbar spinal canal stenosis. PGE₁ improves the mean walking distance in patients with NIC type cauda equina compression. PGE₁ derivate might be effective in dilating blood vessels and improving blood flow in nerve roots with chronically compressed cauda equina. The aim of this study was to assess whether PGE₁ derivate has vasodilatory effects on both arteries and veins in a canine model of chronic cauda equina compression.     

Assessment of lumbar spinal canal stenosis by magnetic resonance phlebography

 There is evidence to suggest that cauda equina intermittent claudication is caused by local circulatory disturbances in the cauda equina as well as compression of the cauda equina. We evaluated the role of magnetic resonance phlebography (MRP) in identifying circulatory disturbances of the vertebral venous system in patients with lumbar spinal canal stenosis. Extensive filling defects of the anterior internal vertebral venous plexus were evident in patients with lumbar spinal canal stenosis (n = 53), whereas only milder abnormalities were noted in patients with other lumbar diseases (n = 16) and none in normal subjects (n = 13). The extent of the defect on MRP correlated with the time at which intermittent claudication appeared. In patients with lumbar spinal canal stenosis, extensive defects of the internal vertebral venous plexus on MRP were noted in the neutral spine position, but the defect diminished with anterior flexion of the spine. This phenomenon correlated closely with the time at which intermittent claudication appeared. Our results highlight the importance of MRP for assessing the underlying mechanism of cauda equina intermittent claudication in patients with lumbar spinal canal stenosis and suggest that congestive venous ischemia is involved in the development of intermittent claudication in these patients. Received: January 16, 2002 / Accepted: August 5, 2002 Offprint requests to: M. Manaka     

动态负荷下前列腺素E_1对受压马尾神经血流量变化的影响

目的 :研究动态负荷下前列腺素E1对受压马尾神经血流量变化的影响。方法 :分 4组 ,每组 6只。除对照组 ,其他 3个实验组制成 3 0 %的双节段狭窄。施加压迫 2h后 ,3个实验组分别施加动态负荷 (高频率刺激和 (或 )压迫追加 ) 6min。实验 3组在施加动态负荷前给予前列腺素E1。结果 :对照组马尾神经血流量在最初 2h无显著变化 ,施加高频率刺激时显著升高至 ( 186.4 -3 1.5 ) % (P <0 .0 5 )。施加动态负荷时 ,实验 1组血流无显著变化 (P >0 .0 5 ) ;实验 2组降至 ( 65 .3 -10 .7) % (P <0 .0 5 ) ;实验 3组为 ( 118.5 -2 3 .6) % ,与实验 2组有显著差异 (P <0 .0 5 )。结论 :双节段压迫会限制马尾神经血流量增加而造成相对缺血。若神经电活动与压迫程度同时增加 ,血流量显著降低 ,造成绝对缺血。前列腺素E1可以在动态负荷下维持马尾神经血流量 ,避免其进入绝对缺血状态。     

Cauda equina syndrome as a postoperative complication in five patients operated for lumbar disc herniation

STUDY DESIGN: A retrospective analysis of records and radiographs in five patients who developed acute cauda equina syndrome after surgery for lumbar disc herniation. OBJECTIVES: To postulate as a possible pathophysiologic mechanism the venous congestion caused by preexisting spinal stenosis and to present a management plan: extended decompression within 48 hours. SUMMARY OF BACKGROUND DATA: Cauda equina syndrome is reported as a sequela in 0.2%-1% of the surgeries for lumbar disc herniation. There is, however, no consensus on the possible pathophysiologic mechanism to the complication or to its management. METHODS: Preoperative investigations consisted of magnetic resonance imaging, or myelography and computed tomography. There was a good correlation between clinical appearance and radiographic findings in all patients. When the complication became apparent in four of the patients, they were investigated with magnetic resonance imaging and reoperated on within 48 hours with wide decompressions. RESULTS: The index operation was reported uneventful in all patients. Postoperative magnetic resonance imaging did not show the cause of the cauda equina syndrome, nor could this be established at the reoperation. Before surgery, all five patients had preexisting narrowing of the spinal canal. In no case was the lumbosacral disc the index level. Two patients recovered fully, whereas the other three experienced varying degrees of residual symptoms. There was no correlation between the end result and the delay until secondary decompression. CONCLUSION: Relative spinal stenosis may contribute to the development of cauda equina syndrome after surgery for lumbar disc herniation. A venous congestion can be triggered by postoperative edema, leading to nerve root ischemia. The treatment of choice seems to be extended decompression within 48 hours.     

Myeloscopic study on lumbar spinal canal stenosis with special reference to intermittent claudication

Twenty-five cases of lumbar spinal canal stenosis were investigated by dynamic myeloscopy to explain the pathophysiologic mechanism of intermittent claudication, one of the characteristic signs of the disorder. Myeloscopic examination revealed that, in accordance with postural alteration, the diameter of blood vessels on the cauda equinae showed significant changes in many patients in the stenosis group, but showed no changes in control group. In this series, it was suggested that the microcirculatory disturbance of vessels on cauda equinae might play an important role in the development of intermittent claudication.     

Cauda equina lesions as a complication of spinal surgery

Although the most common aetiology of cauda equina lesions is lumbar intervertebral disc herniation, iatrogenic lesions may also be the cause. The aim of this study was to identify and present patients in whom cauda equina lesions occurred after spinal surgery. From the author’s series of patients with cauda equina lesions, those with the appearance of sacral symptoms after spinal surgery were identified. To demonstrate lesions more objectively, electrodiagnostic studies were performed in addition to history and clinical examination. Imaging studies were also reviewed. Of 69 patients from the series, 11 patients in whom a cauda equina lesion developed after spinal surgery were identified. The aetiology comprised surgery for herniated intervertebral disc in 5 (4 performed by a single surgeon), spinal stenosis surgery in 4, and postoperative lumbar epidural haematoma in 2 patients (each performed by a different surgeon). Proportion of spinal surgeries with this complication varied from 0 to 6.6‰ in different centres. Patients with iatrogenic cauda equina lesion were significantly older (p < 0.001), and reported more severe urinary, but similar bowel and sexual symptoms compared to other patients in the series. In conclusion the study identified spinal surgery as the cause of approximately 15% of cauda equina lesions. More than a third of lesions developed after procedures performed by a single surgeon. Most of the remaining lesions could probably be avoided by better surgical technique (e.g. the use of a high-speed drill instead of a Kerrison rongeur in patients with severe spinal stenosis), or prevented by closer postoperative monitoring (e.g. in patients with postoperative lumbar epidural haematoma).     

Lumbar spinal stenosis. Radiographic diagnosis with special reference to transverse axial tomography.

Spinal stenosis due to malalignment and/or hypertrophy of the bony margins of the spinal canal is a recognized cause of cauda equina compression and nerve root entrapment. The plain lumbosacral spine roentgenograms reveal the number of lumbar vertebrae, their alignment, their interpedicular distances, the height of the intervertebral disk spaces and the presence of osteophyte formation. It correlates poorly with encroachment on the spinal canal. The transverse axial tomogram directly demonstrates a cross-section of the spinal canal and will show abnormal areas of bone encroachment usually arising from hypertrophied lamina and articular processes. These narrow the posterior portion of the spinal canal and encroach on the lateral recesses. This examination does not demonstrate soft tissue hypertrophy and the stenosis may be even greater than what is apparent due to the bony encroachment. The myelogram expresses how the narrowed spinal canal affects the dural sac and its contained cauda equina. Not infrequently there is an associated herniated disk.     

A case of traumatic spinal subarachnoid hematoma causing compression of the cauda equina]

A case of traumatic spinal subarachnoid hematoma causing compression of the cauda equina is reported here. The patient, a 76 year-old woman, who had fallen down by accident 1 month before, was admitted to our hospital presenting lumbar pain radiating into her right thigh, monoplegia of the right leg and urinary incontinence. Myelography and metrizamide CT demonstrated a filling defect mimicking intradural extramedullary tumor at the level of L1 and L2. Magnetic resonance imagings (MRI) revealed a subacute or chronic hematoma compressing the conus medullaris and the cauda equina. Operation was performed and an old hematoma, which occupied most of the spinal subarachnoid space and compressed the conus and cauda equina from right to left, was removed. No definite bleeding point was detected and no traumatic change was seen on the cord. Neither tumor nor abnormal vessel was detected. After surgery, the symptoms improved partially. On a review of the literature, we found only 4 cases of traumatic spinal subarachnoid hematoma, all of which occupied the cervical or thoracic portion of the spine. Our case is the first report, except for the cases following lumbar spinal tap, of traumatic spinal subarachnoid hematoma causing compression of the cauda equina. Though usually blood in CSF diffuses immediately, a clot may be formed when a large amount of bleeding obstructs the spinal canal. In our case, furthermore, deformity and narrowing of the spinal canal had preceded for many years, following lumbar vertebral compressed fracture related with osteoporosis. This might have promoted the process of canal obstruction and clot formation.(ABSTRACT TRUNCATED AT 250 WORDS)     

前列腺素E1在动态负荷下对大鼠受压马尾神经电生理的影响

目的：研究动态因素下前列腺索E1对大鼠马尾神经电生理变化的影响。方法：分4组，每组6只。除正常对照组，其他三个实验组使用硅胶片插入L4及L6椎管造成横截面积减小30％的双节段狭窄。压迫施加2h后，三个实验组分别施加动态负荷(高频率刺激和/或压迫追加)6min。PGE1压迫增加组在施加动态负荷前给与前列腺素E1。结果：压迫2h后，各实验组神经传导速度均显著下降。动态负荷下，HFS褐压迫增加组出现了神经传导阻滞，而应用了前列腺累E1的PGE4压迫增加组则部分避免了其发生。结论：受压状态中的马尾神经在动态负荷下，前列腺索E1可以防止神经传导阻滞的发生，对神经传导功有保护作用，它可以作为一种非手术治疗腰椎管狭窄症的选择。     

Cauda equina syndrome: a complication of lumbar discectomy

Six cases of acute postdiscectomy cauda equina syndrome (C.E.S.) following lumbar discectomy were reviewed retrospectively in a series of 2842 lumbar discectomies over a ten-year period. Five cases had coexisting bony spinal stenosis at the level of the disc protrusion. The bony spinal stenosis was not decompressed at the time of discectomy. Inadequate decompression played a role in the neurologic deterioration postoperation. The cause of the sixth case is unknown. Bowel and bladder recovery was good when the cauda equina decompressed early; sensory recovery was universally good, and motor recovery was poor if a severe deficit had developed before decompression. Careful review of the preoperative myelogram to rule out spinal stenosis and decompression of bony stenosis at discectomy are recommended for prevention of postoperative C.E.S. Urgent decompression of postoperative C.E.S. is advisable if compression of the cauda equina is confirmed radiographically.     

胸腰椎骨折椎管狭窄与神经功能的关系

对106例连续性胸腰椎爆裂骨折进行回顾性研究,探讨椎管狭窄与神经功能的关系。按自行设计的改良Frankel法将神经功能分六级,将椎管分脊髓圆锥段和马尾神经段,用直线回归相关法分析椎管狭窄与神经损伤程度之间的关系,用等级相关法分析椎管狭窄与发生神经损伤可能性之间的关系。结果表明:无论在脊髓圆锥段或马尾神经段,椎管狭窄与神经损伤程度、损伤可能性之间均存在相关性(r或r_s=0.38～0.90,P<0.05),且脊髓圆锥段的相关程度较高;相同程度椎骨狭窄致神经危害性在脊髓圆锥段较大。发生神经损伤的最小椎管狭窄在脊髓圆锥段为38％,在马尾神经段为63％(?)认为胸腰椎骨折椎管狭窄是神经损伤的主要因素,X-CT扫描可较好地预测神经损伤程度和损伤可能性。     

氟骨症性椎管狭窄症的手术治疗

１９８７～１９９０年手术治疗氟骨症性椎管狭窄症１００例。包括颈椎９例，胸椎８例，腰、骶椎８３例。术后随访１～４年，复查结果：临床治愈９３例（９３％）：显效３例（３％）、有效３例（３％）、无效１例（１％）。手术原则是彻底减压，因氟骨症具有椎骨及其骨周组织严重退变、异化和骨化的临床病理特点，故在胸、腰椎减压术后，一般不影响其稳定性，在颈椎施行双开式或单开式椎管扩大加植骨融合术，则可收减压、稳定及防止或减少椎板间隙瘢痕狭窄的效果。     

马尾神经功能障碍型腰椎间盘突出症的诊断与治疗

目的：介绍合并有马尾神经功能障碍的腰椎间盘突出症的诊断与治疗方法。方法：发生马尾神经功能障碍型腰椎间盘突出症的病人，大多为青壮年，强体力劳动者或体育运动员，因急性腰扭伤而发病。受伤后出现瘫痪症状和马鞍区麻痹、大小便失禁等现象，经X线拍片、CT和MRI检查，明确诊断后，应立即进行手术治疗。结果：作者报告10例，均经关节突间或半椎板切除入路，切除巨块型椎间盘，彻底减压马尾神经，术后均能得到良好的功能恢复，疼痛消失，唯大小便的功能恢复较迟，约在术后1～3周后尚能恢复。结论：马尾神经功能障碍型腰椎间盘突出症，应与马尾肿瘤相鉴别，一旦被确诊为巨块型腰椎间盘突出症，就应立即进行手术治疗，越早手术效果越好。     

Degenerative spondylolisthesis.

Degenerative spondylolisthesis is one important type of spinal stenosis. The spinal canal stenosis varies in degree. This is the result of anterior slipping of the whole vertebra, usually L4 on L5. The clinical picture is not greatly different from that observed in the other types of lumbar canal stenosis. The surgical management involves decompression of the cauda equina by laminectomy. Often this is associated with arthrectomy to decompress the nerve roots. Extensive excision of the neural arch may result in further spinal instability for which spinal fusion is generally advisable.     

不同程度椎管狭窄对马尾神经脑脊液营养来源影响的实验研究

目的：探讨不同程度腰椎椎管狭窄对马尾神经脑脊液营养来源的影响。方法：将^3H-甲基葡萄糖注入不同程度腰椎椎狭窄模型动物的脑脊液中，5min后分别测定脑脊液（Rcsf)和不同节段马尾神经组织（R）中放射性同位素的放射强度，并换算成R／Rcsf。结果：25％、50％狭窄组狭窄段及以远段马尾神经的R／Rcsf较正常组和对照组均有非常显著（P＜0．001）或显著性（P＜0．05）降低，50％狭窄组较25％狭窄组降低更加显著（P＜0．05）。结论：腰椎椎管狭窄在狭窄段及狭窄以远段造成了马尾神经脑脊液来源的营养障碍，并随狭窄程度的增加而愈加明显。马尾神经脑脊液来源的营养障碍可能是马尾神经受损表现的重要病理生理基础。     

Spinal stenosis: assessment of motor function,VEGF expression and angiogenesis in an experimental model in the rat

Reduction of blood flow in compressed nerve roots is considered as one important mechanism of induction of neurogenic intermittent claudication in lumbar spinal canal stenosis. Vascular endothelial growth factor (VEGF) is a potent stimulator of angiogenesis, and is increased in expression in hypoxic conditions. The objective of this study was to examine if cauda equina compression affects motor function and induces expression of VEGF and angiogenesis. The cauda equina was compressed by placing a piece of silicone rubber into the L5 epidural space. Walking duration was examined by rota-rod testing. The compressed parts of the cauda equina and L5 dorsal root ganglion (DRG) were removed at 3, 7, 14, or 28 days after surgery, and processed for immunohistochemistry for VEGF and Factor VIII (marker for vascular endothelial cells). Numbers of VEGF-immunoreactive (IR) cells and vascular density were examined. Walking duration was decreased after induction of cauda equina compression. The number of VEGF-IR cells in the cauda equina and DRG was significantly increased at 3, 14, and 28 days after cauda equina compression, compared with sham-operated rats (P < 0.05). Vascular density in the cauda equina was not increased at any of the time points examined. Cauda equina compression decreased walking duration, and induced VEGF expression in nerve roots and DRG.     

Redundant nerve roots in patients with degenerative lumbar spinal stenosis

Extensive fundamental and clinical investigations have been performed concerning redundant nerve roots (RNR) and the pathogenesis of cauda equina claudication (CEC) in degenerative lumbar canal stenosis (DLCS). These investigations consisted of (1) anatomic observations on RNR in 117 fixed cadaveric specimens, (2) myelographic study in 117 patients with or without DLCS, (3) operative observation on neural elements with special reference to the cauda equina in 56 DLCS patients (including a postoperative follow-up), and (4) electrophysiologic tests using spinal cord action potential recording under walking load preoperatively and intraoperative measurement of nerve conduction velocity of RNR. The RNR have neuronal losses resulting from a longer duration stenosis that suggests a sort of friction neuritis. Complicated factors contribute to the pathogenesis of CEC and the development of root gripping, such as the magnitude of RNR, the extent of the stenosis, a narrowed sac, age-dependent axial shortening of the spinal canal, and dynamic or postural factors. In cases with severe RNR, satisfactory operative results can be obtained only after thorough decompression with dural incision.     

Urodynamic evaluation of patients with spinal stenosis

Spinal stenosis, which may be congenital/developmental or acquired in origin, is a narrowing of the spinal canal, nerve root canals, or intervertebral foramina. Compression of the spinal cord or nerve roots may lead to structural neuronal damage, neuronal ischemia or edema, and axonal transport block. The most frequent symptom in patients with spinal stenosis is back pain and some have classic neurogenic claudication. We have performed urodynamic evaluations in 2 patients with combined cervical and lumbar spinal stenosis. A girl with achondroplastic dwarfism had urgency incontinence and detrusor hyperreflexia. An adult man with acquired degenerative spinal stenosis had difficulty voiding and findings compatible with the cauda equina syndrome.     

Posterior lumbar interbody fusion

This paper reports the posterior lumbar interbody fusion (PLIF) that has been performed on fourteen patients. It includes 6 cases of spondylolytic spondylolisthesis, 3 cases of degenerative spondylolisthesis, 2 cases of postoperative recurrence of lumbar disc protrusion, 2 cases of unstable prolapse of intervertebral disc, 1 cases of consequent spinal canal stenosis after lumbar lamina fusion. As a result 92 per cent of the operations are successful. The method of operation and it's modification are reported in detail. The indication of operation and the evaluative criteria of interbody bone union discussed. The intact of lumbar posterior structures, the condition of bone grating bed, the quality and disperse of bone graft are main factors that influencing bone union. Bleeding from venous plexus of spinal canal and from vertebral cancellous bone, injury of lumbosacral nerve root and cauda equina are the main surgical complications that should be stressed.