Reduction of pathological and behavioral deficits following spinal cord contusion injury with the selective cyclooxygenase-2 inhibitor NS-398

Spinal cord injury (SCI) results in loss of locomotor function and development of abnormal chronic pain syndromes (mechanical allodynia, thermal hyperalgesia). Following injury, secondary mechanisms including release of excitatory amino acids, inflammation and lipid peroxidation damage neural cells through release of cytotoxic free radicals. We hypothesized that selective inhibition of cyclooxygenase-2 (COX-2), an inducible inflammatory mediator, would decrease tissue damage and subsequently reduce locomotor deficits and development of chronic central pain syndromes after injury. Fifteen minutes prior to receiving T13 spinal segment spinal cord contusion injury, 200-225-g male Sprague-Dawley rats received either vehicle (0.5 ml 1:1 v/v DMSO/saline, i.p., n = 20) or the selective COX-2 inhibitor NS-398 (5 mg/kg in DMSO/saline v/v, i.p., n = 20). Locomotor function via the BBB scale, and nociceptive behaviors measured by paw withdrawals to von Frey filaments and radiant heat stimuli were tested for 4 weeks postinjury. Histological examination and volumetric analysis of spinal cord tissue were performed concomitantly. Spinally contused animals receiving NS-398 demonstrated significantly (p < 0.05) reduced locomotor alteration and reductions in both fore- and hindlimb mechanical allodynia and thermal hyperalgesia when compared to vehicle controls. Histological examination of spinal segments at the lesion segment demonstrated reduced lesion extent and increased viable tissue when compared to vehicle controls. Prostaglandin E2 levels were significantly lowered in NS-398-treated but not vehicle-treated animals 12 h after injury. These results support the role of COX-2 in reducing pathological and behavioral deficits after spinal cord injury.     

Development of a chronic cervical cord compression model in rat: changes in the neurological behaviors and radiological and pathological findings

Cervical myelopathy is caused by chronic segmental compression of the spinal cord because of degenerative changes of the spine. However, the exact mechanisms of chronic cervical cord compression are not fully understood. The purpose of this study was to validate a new animal model of chronic cervical cord compression capable of reproducing the clinical course without laminectomy in rats. A polyethylene line attached to a plastic plate was fastened with three turns around the vertebral body of C4 in 1-month-old rats. After surgery, the polyethylene line grows deeper into the dorsal wall of the spinal canal along with the growth of the spinal canal and vertebral body, producing a gradual compression of the spinal cord. The results show that this cervical canal stenosis (CCS) model in rats caused motor deficits and sensory disturbances 9 months after initiating CCS; however, no clinical manifestations took place until 6 months. The intramedullary high-intensity area on T2-weighted images was observed in 70% of the CCS model rats at 12 months after initiating CCS. In histological sections, the spinal cord was compressed along the entire circumference at 12 months after initiating CCS. The number of ventral neurons was decreased, and the white matter showed wallerian degeneration. This model might reproduce characteristic features of clinical chronic cervical cord compression, including progressive motor and sensory disturbances after a latency period and insidious neuronal loss, and represents chronic compression of the cervical spinal cord in humans.     

Cervical Spondylotic Myelopathy: Pathophysiology, Clinical Presentation, and Treatment

Age-related changes in the spinal column result in a degenerative cascade known as spondylosis. Genetic, environmental, and occupational influences may play a role. These spondylotic changes may result in direct compressive and ischemic dysfunction of the spinal cord known as cervical spondylotic myelopathy (CSM). Both static and dynamic factors contribute to the pathogenesis. CSM may present as subclinical stenosis or may follow a more pernicious and progressive course. Most reports of the natural history of CSM involve periods of quiescent disease with intermittent episodes of neurologic decline. If conservative treatment is chosen for mild CSM, close clinical and radiographic follow-up should be undertaken in addition to precautions for trauma-related neurologic sequelae. Operative treatment remains the standard of care for moderate to severe CSM and is most effective in preventing the progression of disease. Anterior surgery is often beneficial in patients with stenotic disease limited to a few segments or in cases in which correction of a kyphotic deformity is desired. Posterior procedures allow decompression of multiple segments simultaneously provided that adequate posterior drift of the cord is attainable from areas of anterior compression. Distinct risks exist with both anterior and posterior surgery and should be considered in clinical decision-making.     

脊髓型颈椎病脊髓受压征象的MRI分级及其临床意义

目的:建立脊髓型颈椎病(cervical spondylotic myelopathy,CSM)脊髓受压征象的MRI分级系统,探讨其可靠性及其与年龄、病程和JOA评分的相关性。方法:收集2010年1月～2011年9月就诊的78例多节段CSM患者的颈椎MRI资料,男51例,女27例;年龄42～77岁,平均55.1岁;病程0.25～276个月,平均48.8个月。以颈椎MRI中脊髓形态、脊髓信号、脊髓与硬膜囊关系作为分级依据征象,将每个征象按照其严重程度分为3个等级,相应赋予0～2分,按3个征象总分划分为四级:0级,0分;Ⅰ级,1～2分;Ⅱ级,3～4分;Ⅲ级,5～6分。由3位初、中、高级职称医师对78例患者的颈椎MRI从C2/3～C6/7进行2次独立分级和1次共同分级,Kappa分析评价每位医师前后2次之间及3位医师之间分级结果的一致性。将3位医师对三个征象共同分级的结果进行Spearman相关分析,同时将患者年龄、病程、术前JOA评分与分级结果进行Spearman相关分析。结果:3位医师分别2次对78例患者的390个节段进行分级,0级82～94个(21.03%～24.10%),Ⅰ级112～126个(28.72%～32.31%),Ⅱ级111～137个(28.46%～35.13%),Ⅲ级47～70个(12.05%～17.95%)。同一医师前后2次分级一致的节段占74.6%～78.5%,Kappa值为0.657～0.706;不同级别医师分级一致的节段占71.5%～76.7%,Kappa值为0.614～0.683。三个征象分级的结果之间相关系数分别为0.552、0.603、0.577,呈显著性正相关(P<0.05)。患者年龄、病程与3位医师共同分级结果的相关系数分别为0.372～0.511、0.388～0.498,呈显著性正相关(P<0.05);术前JOA评分与3位医师共同分级结果的相关系数为-0.409～-0.546,呈显著性负相关(P<0.05)。结论:依据脊髓形态、脊髓信号、脊髓与硬膜囊关系建立的脊髓型颈椎病脊髓受压征象的MRI分级系统具有良好的一致性,其与患者年龄、病程呈正性相关,而与术前JOA评分呈负性相关,对脊髓受压后病变的严重程度评估和研究有指导意义。     

The effect of surgical immobilization after laminectomy in the treatment of advanced cases of cervical spondylotic myelopathy

Summary Surgical immobilization of the cervical spine after laminectomy is proposed for the treatment of severe cervical spondylotic myelopathy (CSM) occurring with diffuse stenosis of the spinal canal (congenital or acquired).In 20 consecutive patients showing advanced CSM and cord compression at various levels, a laminectomy with posterior fixation was made, in most cases with the aid of a metal plate. In the evaluation of the severity of the myelopathy a slight modification of the Nurick scale was used.With the exception of three patients who developed complications unrelated to the technique, the results were very good as demonstrated by the long lasting improvement in the performance of the patients.The results emphasize the role which mechanical factors may play both, in the genesis of the disease and in the failures of the plain laminectomy.     

The pathophysiology and biological mechanisms of cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is a common degenerative disease of the spine that is the direct result of spinal cord compression. With age, the spine undergoes natural degenerative changes that can affect its basic anatomy and lead to stenosis of the spinal canal. Various pathologies involving the vertebrae, intervertebral discs, facet joints, and ligaments of the vertebral column can all contribute to the manifestation of this disease and can be categorized into either static or dynamic mechanisms. Of the static mechanisms, degeneration of the intervertebral discs is one of the most characteristic processes associated with CSM. The formation of osteophytes, ossification of the posterior longitudinal ligament (OPLL), ossification of the ligamentum flavum (OLF), and a genetic predisposition to have a tightened spinal canal are also static pathologies that can contribute to the presentation of myelopathic symptoms in patients. Dynamic mechanisms primarily involve excessive motion of the cervical spine due to traumatic injuries, such as motor vehicle collisions. On a macroscopic level, damage to blood vessels and soft tissue can occur due to the previously described mechanisms; however, on a microscopic level, the pressure from constant spinal cord compression can result in ischemia, an underlying mechanism of CSM and the primary molecular cause of the disease. When the neurons of the spinal cord are deprived of oxygen and essential nutrients due to compression, they initiate an irreversible apoptotic cascade in the affected tissue. This molecular sequence of events is believed to target oligodendrocytes and cause the demyelination of adjacent neurons. As oligodendrocytes die, chronic demyelination of the neurons in the spinal cord occurs, causing residual or even permanent nerve damage after surgical decompression. The exact molecular pathway that results in the debilitating symptoms associated with this disease is not yet fully understood. A better understanding of both the biologic and mechanical mechanisms that cause CSM will significantly improve physicians׳ ability to treat patients diagnosed with this disease and decrease the prevalence of patients suffering from spinal cord impairment.     

脊髓型颈椎病患者颈椎动态MRI检查价值与安全性分析

目的 探究脊髓型颈椎病（CSM）患者颈椎动态MRI（DMRI）检查的价值与安全性。方法 2019年1月—2021年9月，87例CSM患者于苏州大学附属第二医院行颈椎DMRI检查。在矢状面前屈、后伸和中立位MRI T2加权像上观察是否存在脊髓隐匿性压迫。记录患者在DMRI检查前后的症状及体征、疼痛视觉模拟量表（VAS）评分。以DMRI检查后原有症状或体征加重或出现新的症状与体征考虑为短期内脊髓损伤加重。结果 87例患者中17例（19.5%）存在脊髓隐匿性压迫，其中2例在前屈位MRI检查中发现，15例在后伸位MRI检查中发现。DMRI检查后73例患者无明显不适，出现颈肩部不适5例，轻度头晕4例，呼吸不畅、轻度胸闷3例，恶心2例，DMRI检查后VAS评分无下降。85例患者无脊髓神经损伤加重，2例脊髓钳夹伴MRI T2加权像高信号改变患者检查后症状、体征加重。结论 颈椎DMRI是一种相对安全的补充检查，19.5%（17/87）的CSM患者在屈、伸位MRI检查中可发现脊髓隐匿压迫，脊髓钳夹损伤伴MRI T2加权像高信号改变的CSM患者应慎行DMRI检查。     

Increased spinal cord movements in cervical spondylotic myelopathy

Background context

Magnetic resonance imaging (MRI) is a very useful diagnostic test for cervical spondylotic myelopathy (CSM) because it can identify degenerative changes within the spinal cord (SC), disclose the extent, localization, and the kind of SC compression, and help rule out other SC disorders. However, the relationships between changes in cerebrospinal fluid (CSF) flow, cord motion, the extent and severity of spinal canal stenosis, and the development of CSM symptoms are not well understood.

Purpose

To evaluate if changes in the velocity of CSF and SC movements provide additional insight into the pathophysiological mechanisms underlying CSM beyond MRI observations of cord compression.

Study design

Prospective radiologic study of recruited patients.

Patient sample

Thirteen CSM subjects and 15 age and gender matched controls.

Outcome measures

Magnetic resonance imaging measures included CSF and SC movement. Cervical cord condition was assessed by the Japanese Orthopaedic Association (JOA) score, compression ratio (CR), and somatosensory evoked potentials (SSEPs) of the tibial and ulnar nerves.

Methods

Phase-contrast imaging at the level of stenosis for patients and at C5 for controls and T₂-weighted images were compared with clinical findings.

Results

Cerebrospinal fluid velocity was significantly reduced in CSM subjects as compared with controls and was related to cord CR. Changes in CSF velocity and cord compression were not correlated with clinical measures (JOA scores, SSEP) or the presence of T₂ hyperintensities. Spinal cord movements, that is, cord displacement and velocity in the craniocaudal axis, were increased in CSM patients. Increased SC movements (ie, total cord displacement) both in the controls and CSM subjects were associated with altered spinal conduction as assessed by SSEP.

Conclusions

This study revealed rather unexpected increased cord movements in the craniocaudal axis in CSM patients that may contribute to myelopathic deteriorations in combination with spinal canal compression. Understanding the relevance of cord movements with respect to supporting the clinical CSM diagnosis or disease monitoring requires further long-term follow-up studies.     

Retro-odontoid pseudotumor concomitant with proximal adjacent cervical spondylotic myelopathy after multilevel anterior cervical discectomy and fusion

Introduction and importanceAdjacent cervical spondylotic myelopathy (CSM) following anterior cervical discectomy and fusion (ACDF) presenting as a retro-odontoid pseudotumor (ROP) is uncommon. This consequence adversely affects hand function, causes gait imbalance and results in other disabilities for the patient. This report describes the successful surgical treatment of a patient with ROP associated with adjacent CSM following multilevel ACDF of the subaxial cervical vertebrae by performing posterior cervical decompression and fusion.Case presentationA 60-year-old-male presented with progressive, disabling cervical myelopathy. He had undergone ACDF C3-C7 for treatment of CSM 16 years ago and his symptoms had fully resolved. Magnetic resonance imaging (MRI) revealed severe cervical spinal cord compression caused by a retro-odontoid mass at the C1-C2 level with upper adjacent segment disease (ASD) of C1-C3. The patient received C1-C3 posterior cervical spinal fusion by C1 lateral mass C2 and C3 pedicle screw fixation and C1-C3 laminectomy. After the surgery, he was able to ambulate independently and the myelopathic symptoms were significantly improved at the 6 months follow-up.Clinical discussionRetro-odontoid pseudotumor concomitant with proximal ASD following ACDF is a rare occurrence. Both diagnosis and surgical management are challenging.ConclusionsPosterior cervical decompression and fusion of C1-C3 is an effective option for treatment of severe cervical spinal cord compression by a retro-odontoid mass at the C1-C2 level combined with ASD after ACDF.     

Cervical spinal stenosis and sports-related cervical cord neurapraxia in children.

STUDY DESIGN: Congenital spinal stenosis has been demonstrated to contribute to cervical cord neurapraxia after cervical spinal cord injury in adult athletes. A sagittal canal diameter <14 mm and/or a Torg ratio (sagittal diameter of the spinal canal: midcervical sagittal vertebral body diameter) of <0.8 are indicative of significant cervical spinal stenosis. Although sports-related cervical spine injuries are common in children, the role of congenital cervical stenosis in the etiology of these injuries remains unclear. OBJECTIVES: The authors measured the sagittal canal diameter and the Torg ratio in children presenting with cervical cord neurapraxia resulting from sports-related cervical spinal cord injuries to determine the presence of congenital spinal stenosis. METHODS: A total of 13 children (9 male, 4 female) presented with cervical cord neurapraxia after a sports-related cervical spinal cord injury. Age ranged from 7 to 15 years (mean +/- SD, 11.5 +/- 2.7 years). The sports involved were football (n = 4), wrestling (n = 2), hockey (n = 2), and soccer, gymnastics, baseball, kickball, and pogosticking (n = 1 each). Lateral cervical spine radiographs were used to determine the sagittal canal diameter and the Torg ratio at C4. RESULTS: The sagittal canal diameter (mean +/- SD, 17.58 +/- 1.63 mm) and the Torg ratio (mean +/- SD, 1.20 +/- 0.24) were normal in all of these children. CONCLUSION: Using the sagittal canal diameter and the Torg ratio as a measurement of congenital spinal stenosis, the authors did not find evidence of congenital cervical spinal stenosis in a group of children with sports-related cervical spinal cord neurapraxia. The occurrence of cervical cord neurapraxia in pediatric patients can be attributed to the mobility of the pediatric spine rather than to congenital cervical spinal stenosis.     

脊髓型颈椎病患者椎间隙狭窄程度与颈椎不稳的关系

目的探讨脊髓型颈椎病(cervicalspondyloticmyelopathy,CSM)患者椎间隙狭窄程度与颈椎不稳和脊髓压迫部位的关系及其对术式选择的意义。方法回顾性分析35例伴有椎间隙明显狭窄的CSM患者的动态X线和MRI表现,观察颈椎不稳和脊髓压迫部位与狭窄椎间隙的关系,并与同期75例椎间隙接近正常的CSM患者比较。结果伴有椎间隙明显狭窄的CSM患者组中,25例狭窄椎间隙上方的邻近椎体出现不稳(71.4%),21例上方邻近椎间盘明显退变(60%)。椎间隙接近正常的CSM患者组,17例存在节段性颈椎不稳(22.7%)。结论CSM患者明显狭窄椎间隙的上方邻近椎体有失稳倾向,上方邻近椎间盘有加速退变的趋势。手术时应注意对邻近节段的处理。     

Carotid and vertebral artery injury in survivors of atlanto-occipital dislocation: case reports and literature review

Atlanto-occipital dislocation (AOD) usually results in immediate death from transection of the upper cervical spinal cord near the spinomedullary junction. However, over the last several decades increasing numbers of AOD survivors have been identified. Although many of these patients initially demonstrate profound neurologic deficits, a number who survive have regained most or all neurologic functions, indicating that they did not suffer mechanical disruption of the spinal cord at the time of AOD. In the survivors, a growing body of evidence indicates that many of the initial neurologic deficits are related to vascular injury to the carotid or vertebral arteries and their branches. We recently encountered three AOD survivors with no evidence of mechanical injury to the spinal cord in which angiography demonstrated vascular injury to the internal carotid artery in the form of vasospasm in one case and to the vertebral arteries in the forms of focal stenosis at the site of dural penetration, focal stenosis and distal vasospasm, and focal stenosis with distal intimal flap and dissection in one case each. Autopsy after one of the three died after cardiac arrest demonstrated diffuse infarction of the cerebrum, cerebellum, midbrain, brainstem, and upper cervical spinal cord without evidence of mechanical laceration or transection of the spinal cord. Recovery of neurologic function in two cases following prompt immobilization and angiography suggests that neurologic deficits secondary to vascular injury are potentially reversible.     

Marked enhancement of anti-allodynic effect by combined intrathecal administration of the adenosine A1-receptor agonist R-phenylisopropyladenosine and morphine in a rat model of central pain

BACKGROUND: There is often no satisfactory treatment for chronic pain after spinal cord injury. We have previously reported that intrathecal (i.t.) administration of the adenosine A1-receptor agonist R-phenylisopropyl-adenosine (R-PIA) or the opioid morphine has anti-allodynic effects in a model of presumed chronic central pain after photochemically induced spinal cord injury in rats. In the present study, we set out to investigate the possible interaction between i.t. R-PIA and morphine in spinally injured rats. METHODS: Sprague-Dawley rats displaying allodynia-like behaviors to mechanical and cold stimuli after photochemically induced spinal cord injury with minor motor deficits were used. R-PIA and morphine, either alone or in combination, were administered i.t. through an implanted catheter to lumbar spinal cord. RESULTS: Cumulative doses of R-PIA or morphine dose-dependently reduced the mechanical allodynia-like behavior, with a threshold of 1 nmol and 1.5 nmol, respectively. When co-administrated, R-PIA and morphine produced marked suppression of mechanical allodynia at doses of 5 pmol and 7.5 pmol, respectively. The effect of i.t. co-administration of R-PIA and morphine on cold allodynia was comparable to i.t. R-PIA alone. The combination of R-PIA and morphine did not increase adverse effects such as motor deficits in comparison to either drug alone. CONCLUSION: These results demonstrate a supra-additive interaction between the adenosine A1-receptor agonist R-PIA and morphine to reduce mechanical allodynia-like behavior in rats with chronic spinal cord injury. The combination of R-PIA and morphine administered spinally may be superior to R-PIA or morphine alone for treating such pain.     

The optimal radiologic method for assessing spinal canal compromise and cord compression in patients with cervical spinal cord injury. Part II: Results of a multicenter study

STUDY DESIGN: A multicenter, retrospective study using computed tomographic and magnetic resonance imaging data to establish quantitative, reliable criteria of canal compromise and cord compression in patients with cervical spinal cord injury. OBJECTIVES: To develop and validate a radiologic assessment tool of spinal canal compromise and cord compression in cervical spinal cord injury for use in clinical trials. SUMMARY OF BACKGROUND DATA: There are few quantitative, reliable criteria for radiologic measurement of cervical spinal canal compromise or cord compression after acute spinal cord injury. METHODS: The study included 71 patients (55 men, 16 women; mean age, 39.7 +/- 18.7 years) with acute cervical spinal cord injury. Causes of spinal cord injury included motor vehicle accidents (n = 36), falls (n = 20), water-related injuries (n = 8), sports (n = 5), assault (n = 1), and farm accidents (n = 1). Canal compromise was measured on computed tomographic scan and T1- and T2-weighted magnetic resonance imaging, and cord compression at the level of maximum injury was measured on T1- and T2-weighted magnetic resonance imaging. All films were assessed by two independent observers. RESULTS: There was a strong correlation of canal compromise and/or cord compression measurements between axial and midsagittal computed tomography, and between axial and midsagittal T2-weighted magnetic resonance imaging. Spinal canal compromise assessed by computed tomography showed a significant although moderate correlation with spinal cord compression assessed by T1- and T2-weighted magnetic resonance imaging. Virtually all patients with canal compromise of 25% or more on computed tomographic scan had evidence of some degree of cord compression on magnetic resonance imaging, but a large number of patients with less than 25% canal compromise on computed tomographic scan also had evidence on magnetic resonance imaging of cord compression. CONCLUSIONS: In patients with cervical spinal cord injury, the midsagittal T1- and T2-weighted magnetic resonance imaging provides an objective, quantifiable, and reliable assessment of spinal cord compression that cannot be adequately assessed by computed tomography alone.     

先天性颈椎管狭窄与脊髓型颈椎病影像学表现以及预后的关系

目的 探讨脊髓型颈椎病(cervical spondylotic myelopathy,CSM)患者先天性颈椎管狭窄(cervical spinal stenosis,CSS)与颈椎MRI改变及预后的关系.方法 回顾性分析自2006年11月至2009年11月,采用前路、后路或前后路联合手术治疗的286例CSM患者的病例资料,根据患者是否存在CSS将患者分为两组,在MRI T2加权像上评价脊髓高信号的等级以及脊髓受压程度.记录患者日本骨科学会评分标准(Japanese Orthopaedic Associatio,JOA)评分、病程和体征,包括感觉减退或者消失、Hoffman征、Babinski征、腱反射.结果 在CSM患者中CSS的发生率为33.6%,先天性CSS组的年龄、JOA评分、病程均大于无CSS组,术后临床改善率小于无CSS组.两组之间性别的差异无统计学意义(x2=0.006,P=1.00),两组之间的颈椎MRI T2加权像脊髓高信号发生率的差异有统计学意义(x2=-62.396,P＜0.001),CSS组脊髓高信号的发生率为70.8%,无CSS组脊髓高信号的发生率为22.6%.先天性CSS组脊髓受压程度相对于无CSS组严重,且先天性CSS组患者体征的数目相对较多.应用多元线性回归分析法得出术后改善率与CSS、病程、临床体征的数目和年龄有关(R2=0.565).结论 先天性CSS患者出现CSM时往往脊髓受压程度较重、MRI T2加权像脊髓内高信号出现的概率大,病程长且预后较差.

Abstract：

Objective To investigate the relationship between the cervical MR images and pathological changes, prognosis in patients with cervical spinal stenosis and cervical spondylotic myelopathy. Methods From Nov. 2006 to Nov. 2009, 286 patients with cervical spondylotic myelopathy were included through retrospective analysis. All patients were divided into two groups according to whether there was cervical stenosis, the grade of increased signal intensity (ISI) in spinal cord and the degree of spinal cord compression was evaluate in T2-weighted MR images of midian sagittal slices. JOA scale, duration of disease,Hoffmann sign, Babinski sign, sensory loss or hypoesthesia, and lower-extremity/upper-extremity hyperreflexia were recorded. Results The incidence rate of cervical spinal stenosis was 33.6% in patients with cervical spondylotic myelopathy. The study showed that the age was smaller (P＜ 0.001 ), preoperative JOA score was higher(P=0.0018), duration of disease was longer(P=0.009), and the recovery rate was lower(P＜ 0.001 )in cervical spinal canal narrowing group comparing with control group. There was no significant difference between the two groups in gender (x2=0.006,P=l.00). There was significant difference between two groups in the incidence of ISI in spinal cord through x2 test(x2=62.396,P＜ 0.001 ). Multivariate analysis indicated that the likelihood of the recovery rate of cervical myelopathy decreased with the presence of cervical spinal stenosis, duration of dieaase, number of neurological signs, age (R2=0.565). Conclusion Patients with congenitally narrow cervical spinal canal have to suffer severe spinal cord compression and high incidence of ISI in spinal cord. The duration of disease is long, and prognosis is poor.     

Tonicity of resuscitative fluids influences outcome after spinal cord injury

OBJECTIVE: This investigation was designed to test the hypothesis that the tonicity of resuscitative fluids administered after spinal cord injury influences the magnitude of secondary injury and, therefore, outcome. METHODS: Rat spinal cords were compressed with 50 g of weight for 5 minutes to produce injury. After spinal cord injury, the animals were randomized into three experimental groups. Group 1 (n = 10) received no fluid resuscitation after spinal cord injury. Group 2 (n = 6) received 5 ml/kg of intravenously administered Ringer's lactate 1 minute after the removal of compression. Group 3 (n = 7) was treated with 5 ml/kg of intravenously administered 7.5% hypertonic saline 1 minute after the removal of compression. Neurological outcome was assessed daily for 10 days using the Basso, Beattie, and Bresnahan locomotor rating scale. Histological evaluations of the spinal cord were obtained on Day 10. RESULTS: The average number of recovery days before the rats were able to spontaneously void their bladders was significantly less (P < 0.05) in the hypertonic saline-treated group. Spontaneous hindlimb movement also occurred sooner in the hypertonic saline-treated animals. The average neurological score was significantly higher (P < 0.05) in the hypertonic saline-treated group during each of the 10 days of recovery. Histological evaluation supported the finding of attenuation of injury in the hypertonic saline-treated animals. CONCLUSION: The results of this investigation with a chronic model of spinal cord injury support the contention that hypertonic saline treatment may provide protection to the spinal cord after mechanical injury.     

Predictive effect of cervical spinal cord compression and corresponding segmental paravertebral muscle degeneration on the severity of symptoms in patients with cervical spondylotic myelopathy

Background ContextPrevious studies have found that cervical sagittal parameters and spinal cord compression are important risk factors for cervical spondylotic myelopathy (CSM). An increasing number of scholars believe that cervical muscle condition is also one of the factors affecting the severity of symptoms in affected patients.PurposeTo determine whether: the degree of corresponding segmental paravertebral muscle degeneration is related to the severity of symptoms in patients with CSM; the degree of cervical spinal cord compression can predict the severity of symptoms in patients with CSM.Study DesignA retrospective study.Patient SampleFrom January 2015 to January 2019, 121 patients with CSM were enrolled.Outcome MeasuresThe visual analog scale (VAS), neck disability index (NDI) and modified Japanese Orthopedic Association (mJOA) were used to assess cervical spinal function and quality of life.MethodsFrom January 2015 to January 2019, 121 patients with CSM were enrolled. The inclusion criterion was the presence of complete cervical lateral radiography and magnetic resonance imaging (MRI) data. The following radiographic parameters were measured: (1) C0-C2 Cobb angle; (2) C2-C7 Cobb angle (CL); (3) T1 slope (T1S); (4) neck tilt (NT); (5) C2-C7 sagittal vertical axis (SVA); and (6) T1S-CL. The following MRI parameters were measured: (1) up(low)-fat/muscle; (2) up(low)-fat/centrum; (3) up(low)-muscle/centrum; (4) cervical cord compression index (CCI); (5) S-index; and (6) cervical spinal cord compression area ratio (S0/S1). The VAS, NDI and mJOA were used to assess cervical spinal function and quality of life. The patients were divided into 2 groups according to the mJOA score: group A (mild-moderate symptom group, mJOA score≥12 points) and group B (severe symptom group, mJOA score<12 points). The Pearson correlation coefficient was used to assess the correlations between cervical sagittal parameters, MRI parameters and functional scores. Logistic regression analysis and ROC curve analysis were performed to identify independent risk factors and critical values.Results.In patients with CSM, the VAS score is positively correlated with NT, up-fat/centrum, S-index and S0/S1. The NDI is positively correlated with NT, up-fat/muscle, up-fat/centrum, S-index, and S0/S1 and negatively correlated with C0-2N and CL. The mJOA score is positively correlated with CL and negatively correlated with C2-7 SVA, CCI, S-index, and S0/S1. Thus, corresponding segmental paravertebral muscle degeneration has relevance to neck pain, but it is not related to limb weakness, neurological dysfunction, gait impairment, sensation or bladder/bowel function dysfunction. Through mJOA score grouping and binary logistic regression analysis, we found that S0/S1 is the only independent risk factor for severe symptoms in patients with CSM. When S0/S1>0.295, the clinical symptoms of patients are more severe. Thus, in clinical practice, when the degree of spinal cord compression exceeds 30%, the clinical symptoms are more severe.ConclusionsIn patients with CSM, corresponding segmental paravertebral muscle degeneration has relevance to neck pain, but it does not relate to limb weakness, neurological dysfunction, gait impairment, sensation or bladder/bowel function dysfunction. Cervical spinal cord compression is the only independent risk factor;when the degree of spinal cord compression exceeds 30%, the clinical symptoms are more severe.     

Spinal canal size in ossification of the posterior longitudinal ligament of the cervical spine

BACKGROUND: The size of the spinal canal is a factor that contributes to the neurologic deficits associated with cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: Bone-window computed tomography (CT) examinations of the cervical spine in 64 patients with cervical OPLL were reviewed. Forty-two patients underwent surgical treatment (anterior decompression: 16 patients, posterior decompression: 26 patients). The remaining 22 patients were managed conservatively. Selection of the surgical approach, anterior or posterior, was based on the longitudinal extent of cord compression. RESULTS: The mean developmental size of the spinal canal in the posterior decompression group (10.7 mm at C4) was significantly smaller than the other 2 groups. The spinal canal was narrowed by OPLL to 2.9 to 10.0 mm. The proportion of the patients showing motor deficits of the lower extremities significantly increased when the sagittal canal diameter was narrowed to less than 8 mm. CONCLUSIONS: This study demonstrates critical values of CT-determined spinal canal stenosis. Developmental size of the spinal canal and the residual anterior-posterior canal diameters resulting from OPLL spinal cord compression are important factors influencing clinical management and the neurologic state.     

Biomechanical analysis of cervical spondylotic myelopathy: The influence of dynamic factors and morphometry of the spinal cord

Abstract

Objective

Patients with cervical spondylotic myelopathy (CSM) have the same clinical symptoms that vary according to the degree of spinal cord compression and the cross-sectional cord shape. We used a three-dimensional finite element method (3D-FEM) to analyze the stress distributions of the spinal cord with neck extension under three cross-sectional cord shapes.

Methods

Experimental condition for the 3D-FEM spinal cord, ligamentum flavum, and anterior compression shape (central, lateral, and diffuse types) was established. To simulate neck extension, the spinal cord was extended by 20° and the ligamentum flavum was shifted distally according to movement of the cephalad lamina.

Results

The stress distribution in the spinal cord increased due to invagination of the ligamentum flavum into the neck extension. The range of stress distribution observed for the diffuse type was wider than for the central and lateral types. In addition, the stress distribution in the spinal cord was increased by the pincer movement of the ligamentum flavum and by the anterior compression of the spinal cord. The range of stress distribution observed for the diffuse type under antero-posterior compression was also wider than for the central and lateral types.

Conclusion

This simulation model showed that the clinical symptoms of CSM due to compression of the diffuse type may be stronger than for the central and lateral types. Therefore, careful follow-up is recommended for anterior compression of the spinal cord of diffuse type.     

颈椎病伴椎管狭窄患者再手术问题探讨

目的：探讨颈椎病伴椎管狭窄患者再手术的原因、手术方式及其相关问题。方法：我院2002年7月～2003年12月对40例颈椎病伴椎管狭窄术后疗效不佳或症状复发的患者进行了后路多节段（5个或以上）减压手术。根据其手术治疗方式及影像学资料分析再手术原因，并进行术后疗效评价。结果：经前路手术者再手术的主要原因为：（1）伴有多节段颈椎管狭窄因素时，只选择部分压迫重的节段行减压融合15例；（2）经前路多节段（≥3个节段）减压融合后，相邻节段继续退变，出现新的脊髓压迫表现及椎间不稳定9例；（3）伴有OPLL时，行部分节段前路减压融合后，病变呈进展表现，产生或加重对脊髓的压迫8例。经后路手术者再手术的原因为：（1）后路减压节段不够5例（包括1例前后路联合手术者）；（2）后路减压不充分3例。再手术后随访1．3～2．7年，平均2．1年，所有患者脊髓功能获得一定的提高，JOA评分改善率为51．3％。结论：颈椎病伴椎管狭窄病例再手术的主要原因为椎管狭窄因素仍然存在，经后路多节段（5个或以上）减压手术治疗可彻底去除颈椎管狭窄因素，有效解除脊髓前、后方所受的压迫，可获得较满意的临床疗效。