Kinematic evaluation of cervical sagittal balance and thoracic inlet alignment in degenerative cervical spondylolisthesis using kinematic magnetic resonance imaging

Background Context

T1 slope is a novel thoracic parameter used to assess cervical spine sagittal balance. Thoracic index (TI) parameters including T1 slope and cervical sagittal alignment parameters may play an important role in degenerative cervical spondylolisthesis (DCS). Current literature regarding the relationship between TI and cervical sagittal alignment parameters in patients with DCS is limited.

The significance of facet joint cross-sectional area on magnetic resonance imaging in relationship to cervical degenerative spondylolisthesis

Background contextCharacteristic changes of the facet joints, including synovial cysts, facet joint hypertrophy, and facet joint effusions, on magnetic resonance imaging (MRI) and computed tomography have been associated with lumbar degenerative spondylolisthesis. The cervical facets have not been examined for associations with cervical degenerative spondylolisthesis similar to those seen in the lumbar spine.PurposeTo define abnormalities of the facet joints seen on supine MRI that correlate with cervical spondylolisthesis seen on upright radiographs.Study designRetrospective radiographic review of consecutive patients with a universally applied standard.Patient sampleA total of 204 consecutive patients from a single institution, with both an MRI and upright radiographs, were reviewed.Outcome measuresSagittal plane displacement on upright lateral radiographs was compared with MRI. The total area of the facet joint and the amount of facet joint asymmetry were measured on an axial MRI.MethodsThe data were analyzed to determine a significant association between the cervical degenerative spondylolisthesis and the following: facet joint asymmetry, increased total area of the facet joint, and age.ResultsDegenerative spondylolisthesis was seen in 26 patients at C3–C4 and in 27 patients at C4–C5. Upright radiographs identified significantly more degenerative spondylolisthesis than MRIs at levels C3–C4 and C4–C5, 26 versus 6 (p<.001) at C3–C4 and 27 versus 11 (p<.001) at C4–C5. Patients with degenerative spondylolisthesis were more likely to be older, have a larger total facet area, and more facet asymmetry at C3–C4 and C4–C5 (p<.05).ConclusionsSupine MRIs underestimate sagittal displacement compared with upright lateral radiographs. Asymmetric facet hypertrophy at C3–C4 and C4–C5 is associated with degenerative spondylolisthesis on upright lateral films even in the absence of anterolisthesis on supine MRIs.     

Lumbar multilevel degenerative spondylolisthesis: radiological evaluation and factors related to anterolisthesis and retrolisthesis

Radiographs of 3,259 outpatients with low back disorders were examined for age, gender, level, direction, degree of slip, lumbar lordosis, pedicle-facet (P-F) angle, facet shape, and disc height. Degenerative lumbar spondylolisthesis was found in 284 (8.7%) of the patients, of which 83 were excluded. Single-level spondylolisthesis was present in 132 of the 201 patients studied, including 93 cases of anterolisthesis and 39 of retrolisthesis, the former being predominant at L4 and in women and the latter at L2 and equal between the genders. Multilevel spondylolisthesis in 69 patients included 65 (94%) of two-segment slip, 21 anterior, 25 posterior, and 19 combined, and 4 cases of three-segment retrolisthesis. Factors related to anterolisthesis were increased P-F angle and W-shaped facet joint; statistically, however, no factors were found statistically related to retrolisthesis. Multilevel anterolisthesis was considered to occur from factors similar to those previously reported for single-level anterolisthesis, and the pathomechanism of retrolisthesis is different from that of anterolisthesis.     

Degenerative spondylolisthesis does not influence surgical results of laminoplasty in elderly cervical spondylotic myelopathy patients

The objective of the study was to investigate the comorbidity of degenerative spondylolisthesis (DS), in elderly cervical spondylotic myelopathy (CSM) patients in our hospital, and the correlation between surgical results and preoperative DS. There are few studies on the outcome of laminoplasty for CSM with DS. A total of 49 elderly patients (>65 years old) who eventually had surgical treatment for CSM were evaluated. A slippage displacement of more than 2.5 mm at least at one level was classified to have a positive DS on flexion/extension radiographs (DS group). A slippage displacement less than 1.0 mm was considered a negative DS (non-DS group). Seventeen patients who had slippage of 1.0–2.5 mm were excluded from the study. The DS group (n = 15) included cases with DS at preoperation, while the remaining cases (n = 17) belonged to the non-DS group. The flexion/extension radiographs of the two groups were compared for range of motion and clinical results at 3 years after the operation. Of all elderly patients, 30.6% had DS. There was no significant difference between the two groups based on the clinical results. The range of motion of all cervical spines (DS group and non-DS group) was significantly limited. However, there was no significant difference between the two groups. New postoperative DS appeared in four patients, of which two were from the DS group and two from the non-DS group. These data suggest that degenerative spondylolisthesis does not influence surgical results in elderly cervical spondylotic myelopathy patients.     

The prevalence of cervical spondylolisthesis.

This study assessed the prevalence of cervical spondylolisthesis in patients undergoing radiographic studies for reasons unrelated to their cervical spine. Scout lateral cervical spine radiographs of 174 patients who had barium swallows were reviewed for the degree and level of cervical spondylolisthesis. Nine patients were found to have >2 mm of anterior subluxation of the cervical spine for a prevalence of 5.2%. Two patients had involvement at the C2-C3 level, one patient at C3-C4, four patients at C4-C5, one patient at C5-C6, and one patient at C7-T1. Subluxation ranged from 2 to 4 mm. Posterior subluxation (retrolisthesis) was not found in any patient. None of the nine patients with spondylolisthesis had complaints of neck pain or upper extremity symptoms, and none had a history of rheumatoid arthritis or cervical trauma.     

Degenerative spondylolisthesis of the cervical spine: analysis of 58 patients treated with anterior cervical decompression and fusion

Background contextDegenerative spondylolisthesis has been well described as a disorder of the lumbar spine. Few authors have suggested that a similar disorder occurs in the cervical spine. To our knowledge, the present study represents the largest series of patients with long-term follow-up who were managed surgically for the treatment of degenerative spondylolisthesis of the cervical spine.PurposeTo describe the clinical presentation and radiographic findings associated with degenerative cervical spondylolisthesis, and to report the long-term results of surgically managed patients.Study designAnalysis of 58 patients treated with anterior cervical decompression and fusion for degenerative spondylolisthesis of the cervical spine.Patient sampleFrom 1974 to 2003, 58 patients were identified as having degenerative spondylolisthesis of the cervical spine occurring in the absence of trauma, systemic inflammatory arthropathy, or congenital abnormality. These patients were identified from a database of approximately 500 patients with degenerative cervical spine disorders treated by the senior one of us.Outcome measuresPatient outcomes were evaluated with regard to neurologic improvement (Nurick grade myelopathy) and osseous fusion.MethodsThe records of 58 patients were reviewed. The average follow-up period was 6.9 years (range, 2–24 years). Seventy-two cervical levels demonstrated spondylolisthesis. In all cases, there was radiographic evidence of facet degeneration and subluxation. All patients were treated with anterior cervical decompression and arthrodesis with iliac crest structural graft. This most commonly involved corpectomy of the caudal vertebrae. Three patients required additional posterior facet fusion.ResultsFifty-eight patients demonstrated 72 levels of involvement. The C4–C5 level was most frequently involved (43%). Two radiographically distinct types of listhesis were observed based on the amount of disc degeneration and the degree of spondylosis at adjacent levels. The average neurologic improvement was 1.5 Nurick grades. The overall fusion rate was 92%. Three patients were treated with combined anterior-posterior arthrodesis. The prevalence of myelopathy and instability pattern was greater in the listheses occurring adjacent to spondylotic levels.ConclusionsDegenerative spondylolisthesis is relatively common in the cervical spine. Common to all cases is facet arthropathy and neurologic compression. Anterior cervical decompression and arthrodesis appears to yield excellent union rates and neurological improvement in those patients having cervical degenerative spondylolisthesis and significant neurological sequelae who have failed nonoperative treatments.     

Influence of facet joint angles and asymmetric disk collapse on degenerative olisthesis of the cervical spine

This study examined the facet angles of the joint facets of the intervertebral joints, the anterior and posterior heights of the intervertebral disks, and cervical lordosis as possible parameters of olisthesis. Lateral radiographs of the cervical spine in 123 patients were examined, and parameters were correlated to anterolisthesis and retrolisthesis in each segment. Results indicate anterolisthesis is caused by a decrease of the facet angles of the caudal joint facets. This process is favored by loss of anterior height of the intervertebral disks and a flattened position of the cervical spine. Loss of posterior height of the intervertebral disks promotes retrolisthesis.     

脊髓型颈椎病MRI T2信号变化与颈椎活动度的关系

目的探讨脊髓型颈椎病患者MRI T2 WI病理信号变化的危险因素。MRI T2 WI信号变化在脊髓型颈椎病患者经常出现,信号强度的不同反映了脊髓的不同病理改变和颈椎病的发生和发展,但目前没有对引起MRI T2 WI信号变化的危险因素进行探讨,尤其是对颈椎病的发生和发展有着重要影响的颈椎动态特性。方法自2009年5月至2012年5月,符合研究纳入标准的71例脊髓型颈椎病患者纳入本研究。按MRI T2 WI信号强度分为三组：组1,信号无增强;组2,信号轻微增强;组3,信号明显增强。颈椎动态指标采用测量直立位颈椎过屈过伸侧位片Cobb角。结果各组间年龄、症状持续时间、术前JOA评分及性别比例差异无统计学意义（P〉0.05）。各组间颈椎整体过屈、过伸弧度、活动度,颈椎节段过屈差异无统计学意义（P〉0.05）。组1与组2、组3在节段过伸弧度与节段活动度差异有统计学意义（P〈0.05）,组2和组3在节段过伸弧度与节段活动度差异无统计学意义（P〉0.05）。结论颈椎节段过伸弧度和活动度增加是脊髓型颈椎病MRI T2 WI出现高信号变化的危险因素。     

Mechanisms of retrolisthesis in the lower lumbar spine. A radiographic study

The study investigates lower lumbar segments with posterior vertebral shifts (retrolisthesis) with respect to the orientation of facet joints, disc height, lordosis of the lumbar spine, and orientation of vertebral endplates. Standing lumbar radiographs as well as CT and/or MRI investigations of 69 patients were analyzed. Data from patients with retrolisthesis (20 cases) were compared to data from patients with degenerative spondylolisthesis (DS, 23 cases), and from patients without signs of vertebral shifts (26 cases). The orientation of facet joints in segments with retrolisthesis was not different from segments without shifts, whereas the facet joints in patients with DS were oriented more sagittally. The overall lordosis of the lumbar spine and the endplate inclination were considerably reduced in patients with retrolisthesis, especially compared to those with DS. Disc height was comparable in retrolisthesis and DS, but was reduced compared to segments without shifts. The results support biomechanical considerations, that a retrolisthesis of a lower lumbar spine segment is correlated with a reduction of lumbar lordosis, endplate inclination, and segmental height.     

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.     

A slip above a slip: retrolisthesis of the motion segment above a spondylolytic spondylolisthesis

Objective

The purpose of this study is to assess the degenerative changes in the motion segments above a L5S1 spondylolytic spondylolisthesis and to view these in light of the retrolisthesis in the segment immediately above the slip.

Background summary

A spondylolytic spondylolisthesis causes an abnormal motion and predisposes to degenerative changes at the L5S1 disc. Degenerative changes in the adjacent segments would influence the symptomatology and natural history of the disease and the treatment options. The extent of degenerative changes in the levels immediately above a L5S1 spondylolytic spondylolisthesis is not well documented in the literature. We have noted retrolisthesis at this level, but this has not been previously reported or assessed.

Materials and methods

Thirty-eight patients with a symptomatic L5S1 spondylolytic spondylolisthesis with a mean age of 52.8 years (95% CI 47.2–58.4); 55.3% (n = 21) females and 44.7% (n = 17) males. We assessed the lumbar lordosis, slip angle, sacral slope, grade of the slip, facet angles at L34 and L45 on both sides, facet degenerative score (cartilage and sclerosis values), disc degenerative score (Pfirrmann) at L34, L45 and L5S1 and the presence of retrolisthesis at L45.

Results

We noted that 29% (11) had a retrolisthesis at L45. The degenerative scores reduced significantly from L5S1 through L45 and L34. Slip angle and L45 disc degenerative score were the only factors that occurred consistently in patients with a retrolisthesis.

Conclusions

There is a cascade of degenerative changes that involve both the disc and the facet joints at the levels above a spondylolytic spondylolisthesis. The degenerative changes at the L45 disc and a higher slip angle are consistent findings in patients with a retrolisthesis at the level above the slip.     

Segmental cervical instability does not drive the loss of cervical lordosis after laminoplasty in patients with cervical spondylotic myelopathy

BACKGROUND/CONTEXTKyphotic deformity after cervical laminoplasty (CLP) often leads to unfavorable neurological recovery due to insufficient indirect decompression of the spinal cord. Existing literature has described that segmental cervical instability is a contraindication for CLP because it is a potential risk factor for kyphotic changes after surgery; however, this has never been confirmed in any clinical studies.PURPOSETo confirm whether segmental cervical instability was an independent risk factor for postoperative kyphotic change and to examine whether segmental cervical instability led to poor neurological outcomes after CLP for cervical spondylotic myelopathy (CSM).STUDY DESIGN/SETTINGA retrospective studyPATIENT SAMPLEPatients who underwent CLP for CSM between January 2013 and January 2021 with a follow-up period of ≥1 year were enrolled.OUTCOME MEASURESCervical radiographic measurements including C2–C7 lordosis (C2–7 angle), cervical sagittal vertical axis, C7 slope, flexion range of motion (fROM) and extension ROM (eROM) were assessed using neutral and flexion-extension views. Segmental cervical instability was classified into anterolisthesis (AL) of ≥2 mm displacement, retrolisthesis (RL) of ≥2 mm displacement, and translational instability (TI) of ≥3 mm translational motion. The amount of C2–7 angle loss at the follow-up period compared to the preoperative measurements was defined as cervical lordosis loss (CLL). Neurological outcomes were assessed using the recovery rate of the Japanese Orthopedic Association score (JOA-RR).METHODSCLL was compared among patients with and without segmental cervical instability. Further, multiple linear regression model for CLL was built for the evaluation with adjustment of the reported risks, including cervical sagittal vertical axis, C7 slope, fROM, eROM, and patient age together with AL, RL, and TI, as independent variables. The JOA-RR was also compared between patients with and without segmental cervical instability.RESULTSA total of 138 patients (mean age, 68.7 years; 65.9% male) were included in the analysis. AL, RL, and TI were found in 12 (8.7%), 33 (23.9%), and 16 (11.6%) patients, respectively. Comparisons among the groups showed that AL led to greater CLL; however, RL and TI did not. Multiple linear regression analysis revealed that greater CLL is significantly associated with greater fROM and smaller eROM (regression coefficient [β]=0.328, 95% confidence interval: 0.178 to 0.478, p<.001; β=?0.372, 95% confidence interval: ?0.591 to ?0.153, p=.001, respectively). However, there were no significant statistical associations in the AL, RL, and TI. Whereas, patients with AL tended to exhibit lower JOA-RR than those without AL (37.8% vs. 52.0%, p=.108).CONCLUSIONSSegmental cervical instability is not the definitive driver for loss of cervical lordosis after CLP in patients with CSM; thus, is not a contraindication in and of itself. However, it is necessary to consider the indications for CLP, according to individual cases of patients with AL on baseline radiograph, which is a sign of poor neurological recovery.     

Magnetic resonance imaging is not needed to clear cervical spines in blunt trauma patients with normal computed tomographic results and no motor deficits

HYPOTHESIS: Trauma patients with normal motor examination results and normal cervical spine helical computed tomographic (CT) scans with sagittal reconstructions do not have significant cervical spine injury. DESIGN: Prospectively collected registry data. SETTING: Level II community-based trauma center. PATIENTS: All patients admitted to the trauma service from January 1, 1999, to December 31, 2003. MAIN OUTCOME MEASURES: Injury detected by CT and/or magnetic resonance imaging (MRI) of the cervical spine. Neurologic examination and need for surgery were secondary outcomes. RESULTS: During the study period, 2854 trauma patients were admitted, of whom 91.2% had blunt trauma. Of these patients, 56.2% had a closed head injury. One hundred patients had cervical spine and/or spinal cord injuries. Eighty-five patients had a cervical spine injury diagnosed by CT. Fifteen patients had admission neurologic deficits not seen on CT, and 7 of these patients had non-bony abnormalities on MRI. Ninety-three patients had a normal admission motor examination result, a CT result negative for trauma, and persistent cervical spine pain, and were examined with MRI. All MRI examination results were negative for clinically significant injury. Seventeen patients had MRIs that showed degenerative disc disease, and 6 had spinal canal stenosis secondary to ossification. Twelve comatose patients (Glasgow Coma Scale score, <9), moving all 4 extremities on arrival, with normal CT results of the cervical spine, were examined with MRI. All of these MRI examination results were negative for injury. None of the patients experienced neurologic deterioration. No patient required operative management of spinal injury. CONCLUSION: Blunt trauma patients with normal motor examination results and normal CT results of the cervical spine do not require further radiologic examination before clearing the cervical spine.     

Anterior approach for complex cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is a slowly progressive disease resulting from age-related degenerative changes in the spine that can lead to spinal cord dysfunction and significant functional disability. The degenerative changes and abnormal motion lead to vertebral body subluxation, osteophyte formation, ligamentum flavum hypertrophy, and spinal canal narrowing. Repetitive movement during normal cervical motion may result in microtrauma to the spinal cord. Disease extent and location dictate the choice of surgical approach. Anterior spinal decompression and instrumented fusion is successful in preventing CSM progression and has been shown to result in functional improvement in most patients.     

MRI信号强度比值判断脊髓型颈椎病预后的意义

 目的 利用量化脊髓MRI信号强度的方法来探讨高信号对判断脊髓型颈椎病预后的意义。方法 2000年 2月至 2008年 2月行后路减压手术治疗且随访 2年以上的多节段脊髓型颈椎病患者 57例,所有患者术前均行高分辨率 1.5T MR扫描.如果患者 T₂加权像存在信号强度增加的区 II 则测量此区 II 信号强度值.同时于 T₁加权像测量与 T2加权像高信号区 II 处于相同节段的脊髓信号强度值.两者测量所取面积相近,操作均于 MR工作台进行。T₂加权像信号强度值与 T₁加权像信号强度值的比值作为研究的 T₂/T₁比值。无 T₂加权像高信号的患者归为无高信号组,T₂加权像高信号的患者以 T₂/T₁比值的中位数为分界点分为低 T₂/T₁比值组和高 T₂/T₁比值组。结果 无高信号组 20例;其他 37例均有T2加权像高信号(T₂/T₁比值范围为 1.28~2.80.中位数为 1.65),分为低 T₂/T₁比值组 19例(1.28≤T₂/T₁≤1.63)和高 T₂/T₁比值组 18例(1.67≤T₂/T₁≤2.80)。经方差分析三组在年龄、病程、术前 JOA评分、术后JOA评分及改善率等指标间差异均有统计学意义。 T₂/T₁比值与年龄、病程呈正相关.与术前、术后 JOA评分及改善率呈负相关。结论 有 T₂加权像高信号的患者其术前病情较重.手术治疗效果较差.并且随着信号强度的增加.这一趋势更加明显。 T₂加权像高信号可作为判断脊髓型颈椎病预后的一项指标。     

Bryan人工间盘置换与前路减压融合治疗颈椎退行性疾病的中期随访研究

 目的 评价人工椎间盘置换术治疗颈椎退行性疾病的中期疗效,并探讨其是否可以减少邻近节段退变的发生。方法 前瞻性对比分析接受颈椎人工间盘置换术(置换组,45例)与颈椎前路减压融合术(融合组,48例)治疗的颈椎退行性疾病患者的随访6年临床疗效和影像学资料。临床疗效评价指标为日本骨科协会评分(Japanese Orthopaedic Association Scores,JOA)、颈椎功能残障指数量表(neck disability index,NDI)和Odom评分。影像学评价指标为矢状位曲度、活动度、邻近节段退变。结果28例置换组患者和35例融合组患者完成随访。两组患者末次随访的JOA评分和NDI均较术前有明显改善,组间比较差异无统计学意义。92.9%的置换组患者和97.1%的融合组患者Odom评分获得很好或较好的结果。两组患者颈椎矢状位曲度末次随访较术前均得到保持。颈椎整体活动度置换组末次随访与术前无明显差异,而融合组则是明显降低。置换组置换节段活动度术前为9.5°±3.7°,术后3个月为7.0°±3.0°,末次随访为6.6°±4.1°,末次随访较术后3个月无明显改变。邻近节段退变评估采用侧位X线片和MRI T2加权像,置换组上、下邻近节段退变均明显少于融合组。结论 Bryan人工椎间盘置换术6年的随访结果基本满意,能更好地保留颈椎生理活动及生物力学环境,从而降低邻近节段退变的发生率。     

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.     

Careful follow-up after "successful" surgery: postoperative spondylolisthesis after anterior cervical corpectomy and fusion with instrumentation

BACKGROUND: Anterior cervical corpectomy and fusion with instrumentation is a common procedure for the surgical treatment of cervical spinal cord and/or nerve root decompression or for deformity correction. However, various postoperative complications have been associated with such a surgical intervention. Postoperative spondylolisthesis after an anterior cervical corpectomy with instrumentation is a serious complication that has rarely been addressed in the literature, and may potentially be underreported. CASE DESCRIPTION: A 44-year-old woman with degenerative disk disease, loss of cervical lordosis, congenital cervical stenosis at C5-C6, and a left-sided herniated disk at C6-C7 underwent an anterior cervical corpectomy of C6 with fusion and anterior plate stabilization of C5-C7. Early postoperative evaluation noted complete resolution of the patient's symptoms. At 6 months after surgery, the patient complained of neck pain and intermittent headaches. Radiographic evaluation noted fusion of the corpectomy strut graft with retrolisthesis of C5 on C6 and early myelomalacia at C5-C6. A cervical laminectomy with posterior instrumentation from C5 to C7 was performed and the patient's symptoms resolved. CONCLUSIONS: Postoperatively, a high index of suspicion should be present for the development of spondylolisthesis in patients undergoing an anterior cervical corpectomy and fusion procedure with or without instrumentation, particularly in individuals with persistent or new symptoms even after a "successful" operative procedure. The spine surgeon should address appropriate operative techniques and postoperative management to decrease the risk of spondylolisthesis after such a procedure.     

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.     

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.