Thoracic and lumbar spine in diastrophic dysplasia: a clinical and magnetic resonance imaging analysis

STUDY DESIGN: Cross-sectional study to evaluate the thoracic and lumbar spine in patients with diastrophic dysplasia (DD). OBJECTIVES: To find the causative factors behind the spinal deformities and restricted mobility of the spine. SUMMARY OF BACKGROUND DATA: Typical findings in this skeletal dysplasia are short-limbed stature, multiple joint contractures, early degeneration of joints, and spinal deformities such as cervical kyphosis, scoliosis, and exaggerated lumbar lordosis. The pathogenic mechanism of scoliosis is unknown. METHODS: A physical examination was performed on 88 patients (55 females, 33 males) with an average age of 31 years (range, 3-56). Magnetic resonance (MR) images from T2 to S1 and radiographs were obtained. Degree of scoliosis was measured according to Cobb from standing radiographs.The anatomy of the medulla and the size of the spinal canal were assessed. The transverse dural tube area was measured from L2 to S1. Disc space, degeneration, and protrusions were evaluated. Vertebral abnormalities, if any, facet joint degeneration and the state of the spinal muscles were also assessed. RESULTS: Physical examination showed diminished mobility of the spine. Scoliosis was noted in 70 patients with an average of 42 degrees (range, 11-188 degrees ). The mean transverse area of the dural tube ranged from 94 mm(2) at L2-L3 to 57 mm(2) at L5-S1. The area was smaller at all levels compared with reference values (P < 0.001). One patient had severe thoracic and lumbar spinal stenosis. Five patients had compression of neural structures in the lumbar spinal canal in MR images, but had no clinical symptoms. All patients exhibited narrowed disc heights and a decrease in the signal intensity of discs on T2-weighted images. The prevalence of disc protrusions was low; three patients had a prolapse in the lumbar spine. Two patients displayed vertebral anomalies. All patients also had muscular atrophy and degenerative-like facet joint hypertrophy. The severity of these changes increased with age. CONCLUSIONS: Abnormal disc structure and rapid degeneration explain the diminished decreased mobility of the spine and may be a causative factor in the development of scoliosis. Muscular atrophy may be caused by reduced physical activity and rigid spinal deformities. The spinal canal is narrowed, but symptomatic lumbar spinal stenosis is uncommon.     

颈腰椎间盘病

目的： 探讨颈腰椎间盘病的特点和诊断。方法： 对近４ 年中的颈腰椎间盘突出症、退变性椎管狭窄和颈椎病并施行手术的１９ 例进行了分析。结果： 发现颈腰椎间盘突出症是本病的重要原因。结论： 根据临床症状、体征和影像学检查, 颈椎 Ｍ Ｒ Ｉ和腰椎 Ｃ Ｔ 检查, 是防范混淆和误诊的必要条件。     

认识颈腰椎间盘病

目的　探讨颈腰椎间盘病的特点和诊断。方法　对近 6年中的颈腰椎盘突出症伴退变性椎管狭窄症和颈椎病并施行手术的 5 6例进行分析。结果　发现颈腰椎间盘突出症是本病的重要原因。结论　根据临床症状、体征和影像学检查 ,颈椎MRI和腰椎CT检查 ,是防范混淆和误诊的必要条件     

Soft cervical disc herniation. Influence of cervical spinal canal measurements on development of neurologic symptoms.

STUDY DESIGN: In 100 consecutive patients who underwent surgery because of soft cervical disc herniation, the sagittal and transverse diameters, the area of the bony cervical spinal canal, the sagittal diameter of the hernia, and the minimal bony intervertebral foramen diameter were measured by computed tomography. The data were compared with measurements from a control group of 35 matched healthy individuals. OBJECTIVES: To evaluate the relation between the severity of concurrent neurologic symptoms and the sagittal and transverse diameters, the cross-sectional area of the bony spinal canal, the sagittal diameter of the hernia, and diameter of the minimal bony intervertebral foramen in patients with soft cervical disc herniation. SUMMARY OF BACKGROUND DATA: Traumatic injury and spondylotic changes have a far greater impact on the spinal cord and nerve roots if the sagittal diameter of the bony cervical spinal canal is small. However, in the case of soft cervical disc herniation, no computer tomographic measurements are available for sagittal and transverse diameters, cross-sectional area of the bony spinal canal, sagittal diameter of the hernia, and diameter of the minimal bony intervertebral foramen in relation to the severity of concurrent neurologic symptoms. METHODS: Computed tomography was used to measure sagittal and transverse diameters, cross-sectional area of the bony cervical spinal canal, sagittal diameter of the hernia, and diameter of the minimal bony intervertebral foramen in 100 patients with symptomatic monosegmental cervical soft disc herniation. All patients had undergone an anterior discectomy with removal of the hernia and subsequent interbody fusion using an autologous bone graft taken from the iliac crest. RESULTS: A mean sagittal diameter of the bony cervical spinal canal of 12.9 mm was found, indicating a certain degree of developmental stenosis. Patients with motor disturbances had a significantly smaller sagittal diameter of the bony spinal canal than did patients without motor disturbances. There was a linear correlation between the sagittal diameter of the bony cervical spinal canal and that of the hernia. The sagittal diameter, the area of the bony spinal canal, and diameter of the minimal bony intervertebral foramen were significantly smaller in patients with soft cervical disc herniation than in the control group. CONCLUSIONS: Results from this study strongly suggest that the degree and severity of neurologic symptoms accompanying cervical soft disc herniation are inversely related to the sagittal diameter and the area of the bony cervical spinal canal. The latter area is reduced in cases of developmental stenosis or because of soft disc herniation. Moreover, patients with soft cervical disc herniation have a significantly smaller sagittal diameter of the bony spinal canal, a significantly smaller minimal bony intervertebral foramen diameter, and a significantly smaller cross-sectional area of the bony cervical canal than do healthy matched individuals.     

Kyphotic malalignment after anterior cervical fusion is one of the factors promoting the degenerative process in adjacent intervertebral levels

The aim of this study was to determine whether postoperative malalignment of the cervical spine after anterior interbody fusion surgery promotes degenerative changes in the neighboring intervertebral discs. Forty-two patients who underwent anterior interbody fusion surgery for cervical spondylosis and disc herniation (34 men, 8 women) were followed for an average of 9.8 years. The average age at surgery was 50.2 years. Twenty-three patients underwent a single-level fusion, 17 underwent two-level fusion, and 2 had three levels fused. The Japanese Orthopaedic Association cervical myelopathy score, with a normal score 17 points, was 11.7 before surgery and 14.9 at follow-up. Neurological status was significantly improved postoperatively, and the improvement was preserved thereafter in most cases (paired t-test, P<0.001). Degenerative changes were evident on radiological examination in the levels adjacent to the fused segment in 21 of the 42 (50%) patients. Eight of these 21 patients demonstrated neurological deterioration caused by an adjacent disc lesion. A total of 43% of the patients with adjacent-level degeneration had malalignment of the cervical spine, such as kyphosis or sigmoid curvature. In addition, degenerative change in adjacent intervertebral levels was observed in 77% of kyphoses of the fused segment. These were statistically significant (Fisher exact method, P<0.05, P<0.04, respectively). Our findings suggest that one of the factors promoting degenerative change in adjacent intervertebral levels after anterior cervical fusion for degenerative disorders is postoperative kyphotic change in the cervical spine and the fused segment.     

人工椎间盘置换术后下腰椎椎管及神经根管改变的初步临床研究

目的探讨人工椎间盘(artificialdiscreplacement,ADR)植入后,下腰椎神经根管、椎管的径线及容积改变,以其为合理的ADR植入提供临床依据。方法7例腰椎间盘突出症分别行ADR置换,观察术后JOA与ODI评分、椎间隙活动度、椎间孔径线改变以及椎间孔、椎管的容积变化。结果ADR术后JOA与ODI评分明显改善,椎间隙与椎管径线与容积显著增加,腰椎节段的稳定性与功能恢复。结论人工椎间盘植入后不仅能改善患者的临床症状,而且能有效地恢复椎管及神经根管径线与容积。目的探讨人工椎间盘(artificialdiscreplacement,ADR)植入后,下腰椎神经根管、椎管的径线及容积改变,以其为合理的ADR植入提供临床依据。方法7例腰椎间盘突出症分别行ADR置换,观察术后JOA与ODI评分、椎间隙活动度、椎间孔径线改变以及椎间孔、椎管的容积变化。结果ADR术后JOA与ODI评分明显改善,椎间隙与椎管径线与容积显著增加,腰椎节段的稳定性与功能恢复。结论人工椎间盘植入后不仅能改善患者的临床症状,而且能有效地恢复椎管及神经根管径线与容积。     

Tandem age-related lumbar and cervical intervertebral disc changes in asymptomatic subjects

Purpose

To investigate the frequency of tandem lumbar and cervical intervertebral disc degeneration in asymptomatic subjects.

Methods

We evaluated magnetic resonance imaging (MRI) results from 94 volunteers (48 men and 46 women; mean age 48 years) for age-related intervertebral disc degeneration in the lumbar and cervical spine.

Results

MRI indicated degenerative changes in the lumbar spine in 79 subjects (84 %), with decreased disc signal intensity in 74.5 %, posterior disc protrusion in 78.7 %, anterior compression of the dura in 81.9 %, disc space narrowing in 21.3 %, and spinal canal stenosis in 12.8 %. These findings were more common in older subjects at caudal levels. MRI showed degenerative changes in both the lumbar and cervical spine in 78.7 % of the volunteers.

Conclusions

Degenerative findings in both the lumbar and cervical spine, suggesting tandem disc degeneration, was common in asymptomatic subjects. These results provide normative data for evaluating patients with degenerative lumbar and cervical disc diseases.     

下腰部神经根管的解剖学观察及临床意义

目的 探讨腰骶神经根管的形态、结构、走行及比邻组织病理改变的特点,提高对病因的认识和临床诊疗水平.方法 选择5具无脊柱疾患的成人腰骶椎段标本,依照后路椎管及神经根管手术探查的习惯入路,分别对下腰部椎管和神经根管后方冠状面、神经根管后壁、前壁及椎间盘横断面进行解剖及观察.结合临床78例腰骶椎手术患者的椎管和神经根管探查所见,相互印证.结果 下腰部神经根自硬膜囊穿出后,随着序列的下降,与硬膜囊的夹角也随之减小,而出发点则随之升高;在途径椎管内及椎间管内两个阶层中,前段一般不受退变及异常应力作用产生形变,增厚的黄韧带多为致病因,后段为纤维管道,不越过间盘组织,可能与骨退变及增生有更大的相关性.结论 神经根自硬膜囊发出后,因序列不同,出发点及角度均不同,与椎间盘关系亦不同,在作髓核摘除时应避免损伤;在整个神经根行走径路中,均可由自身的增生退变或以合并存在的形式导致途径的神经根发生嵌压引发临床症状和体症,由于病变部位和病变组织性质不同,手术方法也不同.     

非手术治疗无骨折脱位型颈脊髓损伤预后的多因素分析

目的 :探讨影响非手术治疗无骨折脱位型颈脊髓损伤预后的因素。方法 :回顾性分析2009年1月至2012年12月接受非手术治疗的122例无骨折脱位型颈脊髓损伤患者的临床资料,其中男84例,女38例;平均年龄(52.37±13.27)岁(18~83岁)。选择年龄、性别、受伤原因、受伤至治疗时间、脊髓损伤ASIA分级、MRI脊髓损伤类型、脊髓损伤范围、有效颈椎管率、椎间盘突出Pfirrmann分级、椎间盘突出节段、椎间盘韧带复合体损伤、大剂量甲基强的松龙冲击治疗12个可能对非手术治疗预后产生影响的因素,应用单因素和多因素Logistic回归分析,研究其对预后的影响。结果:单因素分析显示MRI脊髓损伤类型、脊髓损伤范围、有效颈椎管率、椎间盘突出Pfirrmann分级、椎间盘突出节段及脊髓损伤ASIA分级均对预后有显著影响(P均0.05)。进一步行多因素分析,按照其作用强度,影响预后的主要因素依次为:MRI脊髓损伤类型、脊髓损伤范围、有效颈椎管率、椎间盘突出Pfirrmann分级、脊髓损伤ASIA分级(P均0.05)。结论 :影响非手术治疗无骨折脱位型颈脊髓损伤预后的主要因素是MRI脊髓损伤类型及范围,同时与有效椎管率、椎间盘突出程度及脊髓损伤ASIA分级相关。对于选择非手术治疗需谨慎,仅适用MRI检查提示脊髓信号无改变或水肿程度轻且范围局限者,其余则建议积极手术治疗。     

认识颈腰椎间盘病

目的：探讨颈腰椎间盘病的特点和诊断。方法：对近6年中的颈腰椎间盘突出症、迟变性椎管狭窄症和颈椎病并施行手术的56例进行了分析。结果：发现颈腰椎间盘突出症是本病的重要原因。结论：根据临床症状、体征和影像学检查，颈椎MRI和腰椎CT检查，是防范混淆和误诊的必要条件。     

无骨折脱位型颈髓损伤的临床研究

目的：探讨颈椎在无骨折脱位情况下出现颈髓损伤的临床机制。方法：观察２４例无骨折脱位型颈髓损伤，重点分析其影像学检查特点。结果：２７％病例合并椎管狭窄，８３％的病例存在椎间盘突出，不同程度压迫脊髓。结论：无骨折脱位型颈脊髓损伤机制中，存在外伤致颈椎间盘损伤，突出的间盘向后压迫损伤颈髓。颈椎间盘损伤受力机制为屈曲→压缩→过伸。颈椎管狭窄、椎间盘退变等是此类脊髓损伤的病理解剖基础     

MRI evaluation of spontaneous intervertebral disc degeneration in the alpaca cervical spine

Animal models have historically provided an appropriate benchmark for understanding human pathology, treatment, and healing, but few animals are known to naturally develop intervertebral disc degeneration. The study of degenerative disc disease and its treatment would greatly benefit from a more comprehensive, and comparable animal model. Alpacas have recently been presented as a potential large animal model of intervertebral disc degeneration due to similarities in spinal posture, disc size, biomechanical flexibility, and natural disc pathology. This research further investigated alpacas by determining the prevalence of intervertebral disc degeneration among an aging alpaca population. Twenty healthy female alpacas comprised two age subgroups (5 young: 2–6 years; and 15 older: 10+ years) and were rated according to the Pfirrmann‐grade for degeneration of the cervical intervertebral discs. Incidence rates of degeneration showed strong correlations with age and spinal level: younger alpacas were nearly immune to developing disc degeneration, and in older animals, disc degeneration had an increased incidence rate and severity at lower cervical levels. Advanced disc degeneration was present in at least one of the cervical intervertebral discs of 47% of the older alpacas, and it was most common at the two lowest cervical intervertebral discs. The prevalence of intervertebral disc degeneration encourages further investigation and application of the lower cervical spine of alpacas and similar camelids as a large animal model of intervertebral disc degeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1776–1783, 2015.     

Etiologic factors of myelopathy. A radiographic evaluation of the aging changes in the cervical spine

The radiographic characteristics of the cervical spine among older individuals were investigated in 100 normal subjects and compared with those of younger subjects. The cervical spine of the older subjects displayed narrowing of intervertebral discs and osteophytoses (posterior osteophytes as well as anterior osteophytes) at the levels of C5-6 and C6-7, where the range of motion was decreased. Such degenerative changes resulted in vertebrolisthesis, especially retrolisthesis, predominantly at the levels of C3-4 and C4-5, where intervertebral disc space was well maintained and mobility was well preserved. Both static and dynamic anteroposterior canal diameter decreased with age. Throughout the aging process the dynamic canal became much narrower than the static canal, except at C2-3. Posterior osteophytes at C5-6 or C6-7 and retrolisthesis at C3-4 or C4-5 were major levels of stenosis associated with changes in the dynamic canal. Following the same evaluation system, 20 elderly patients with cervical spondylotic myelopathy were assessed. Based on the above-noted characteristics of the aging process, patients with myelopathy had smaller static and dynamic canal measurements than normal subjects. The development of cervical myelopathy, however, was not always based on critical static or dynamic canal stenosis (10% in this series) and might involve other factors.     

Management of cervical and lumbar stenosis]

Spinal stenosis is most common in elderly patients and is defined as narrowing of the spinal canal and (or) lateral nerve root canals. The underlying processes leading to spinal stenosis are degenerative changes in facet joints and intervertebral discs and buckling of the ligamentum flavum. Spinal stenosis can occur in both the cervical and the lumbar spine. Cervical stenosis mayleat to the development of radiculopathy and (or) myelopathy. The majority of patients respond to nonoperative management. Degenerative lumbar spinal stenosis presents with back and (or) leg paints of valuing severity and duration. Nonoperative treatment associated with lumbar spinal stenosis consists of restituting and avoiding those maneuvers that reproduce pain. Surgical treatment of cervical and lumbar stenosis includes decompressive lamine ctomy, often fusion and instrumentation.     

The relationship between the cervical spinal canal diameter and the pathological changes in the cervical spine

A congenitally narrow cervical spinal canal has been established as an important risk factor for the development of cervical spondylotic myelopathy. However, few reports have described the mechanism underlying this risk. In this study, we investigate the relationship between cervical spinal canal narrowing and pathological changes in the cervical spine using positional magnetic resonance imaging (MRI). Two hundred and ninety-five symptomatic patients underwent cervical MRI in the weight-bearing position with dynamic motion (flexion, neutral, and extension) of the cervical spine. The sagittal cervical spinal canal diameter and cervical segmental angular motion were measured and calculated. Each segment was assessed for the extent of intervertebral disc degeneration and cervical cord compression. Based on the sagittal canal diameter, the subjects were classified into three groups: A, subjects with a congenitally narrow canal, diameter of less than 13 mm; B, subjects with a normal canal, diameter of 13–15 mm; C, subjects with a wide canal, diameter of more than 15 mm. When compared with Groups A and B, the disc degeneration grades at the C3-4, C5-6, and C6-7 segments and the cervical cord compression scores at the C3-4 and C5-6 segments showed significant differences. Additionally, when compare with Groups A and C, the disc degeneration grades at all segments, except C2-3, and the cervical cord compression scores at all segments, except C2-3, showed significant differences. With respect to the cervical kinematics, few differences in the kinematics were observed between Groups B and C, however, the kinematics in Group A was different with other two groups. In Group A, the segmental mobility at the C4-5 and C6-7 segments were significantly higher than those observed in Group B, and the segmental mobility at the C3-4 segment was significantly lower than that observed in Groups B or C. We demonstrated the unique pathological and kinematic traits of cervical spine that exist in a congenitally narrow canal. We hypothesize that kinematic trait associated with a congenitally narrow canal may greatly contribute to pathological changes in the cervical spine. Our results suggest that cervical spinal canal diameter of less than 13 mm may be associated with an increased risk for development of pathological changes in cervical intervertebral discs. Subsequently, the presence of a congenitally narrow canal can expose individuals to a greater risk of developing cervical spinal stenosis.     

Internal stress distribution in cervical intervertebral discs: the influence of an artificial cervical joint and simulated anterior interbody fusion

There is concern that cervical interbody fusion can result in accelerated degenerative changes occurring at adjacent spinal levels. The cervical spine clearly evolved to be mobile. It would seem to be desirable for spinal surgeons to have an alternative to fusion, and spinal arthroplasty is an appealing concept. The Bristol Disc is a mechanical device comprising two articulating components that result in motion with 6 df. It has been shown to have favorable kinematics when compared with intact and fused cadaveric spines. The current study attempts to record changes in the distribution of stresses within cervical intervertebral discs adjacent to the artificial disc or a simulated fusion. The technique used to measure intradiscal stress distributions is based on earlier work by McNally and Adams on lumbar intervertebral discs. The study generated stress profiles through cervical intervertebral discs statically loaded in four different postures in addition to recording changes in intradiscal pressure within both the nucleus and the annulus during flexion. Similar stress profiles were recorded from intact specimens and those with the artificial joint inserted. The artificial joint resulted in reduced stresses in the annulus compared with spines with a simulated fusion. The study demonstrates how different testing conditions can result in researchers being confronted with paradoxical data, and the simulation of muscle forces is recommended.     

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。     

Synovial cysts of the spine

A series of 13 patients with synovial or ganglion cysts of the spinal facet joints causing nerve root compression is reported. These cysts were found in both the cervical and the lumbar spine, and the anatomical location of each cyst corresponded to the patient's signs and symptoms. In no case was there evidence of intervertebral disc abnormality found at operation. The patients ranged from 49 to 77 years of age and included 4 men and 9 women. Radiographic evidence of facet degenerative change and degenerative spondylolisthesis was frequently but not invariably noted. The extradural defects defined with positive contrast myelography or postmyelography computed tomographic scanning were usually posterior or posterolateral to the common dural sac and were misinterpreted as extruded discs in the majority of cases. Treatment consisted of laminectomy and surgical excision of cysts. All patients reported improvement or resolution of their presenting symptoms.     

Strain on intervertebral discs after anterior cervical decompression and fusion

STUDY DESIGN: An analysis of the change in strain distribution of intervertebral discs present after anterior cervical decompression and fusion by an original method. The analytical results were compared to occurrence of herniation of the intervertebral disc on magnetic resonance imaging. OBJECTIVES: To elucidate the influence of anterior cervical decompression and fusion on the unfused segments of the spine. SUMMARY OF BACKGROUND DATA: There is no consensus regarding the exact significance of the biomechanical change in the unfused segment present after surgery. METHODS: Ninety-six patients subjected to anterior cervical decompression and fusion for herniation of intervertebral discs were examined. Shear strain and longitudinal strain of intervertebral discs were analyzed on pre- and postoperative lateral dynamic routine radiography of the cervical spine. Thirty of the 96 patients were examined by magnetic resonance imaging before and after surgery, and the relation between alteration in strains and postsurgical occurrence of disc herniation was examined. RESULTS: In the cases of double- or triple-level fusion, shear strain of adjacent segments had increased 20% on average 1 year after surgery. Thirteen intervertebral discs that had an abnormally high degree of strain showed an increase in longitudinal strain after surgery. Eleven (85%) of the 13 discs that showed an abnormal increase in longitudinal strain had herniation in the same intervertebral discs with compression of the spinal cord during the follow-up period. Relief of symptoms was significantly poor in the patients with recent herniation. CONCLUSIONS: Close attention should be paid to long-term biomechanical changes in the unfused segment.     

Achondroplasia with respiratory disturbance: case report]

Achondroplasia often accompanies stenosis of both the foramen magnum and the upper cervical spinal canal. Most infants die as a result of respiratory disturbance, including upper airway obstruction, chest deformity, and compression of the cervicomedullary junction. Especially, young patients under 4 years old sometimes suffered sudden death. Therefore, we think it is necessary to perform preventive surgery when the patient's cervicomedullary junction is compressed markedly even if the symptom is mild. The patient is a 2-year-old girl. She has experienced mild respiratory disturbance since she was born. MRI showed the foramen magnum was narrowed and there was high signal intensity in her cervicomedullary junction. We performed foramen magnum decompression. After the surgery, her respiratory function improved and MRI disclosed her foramen magnum was well decompressed.