The natural history of the cervical foramen in symptomatic and asymptomatic individuals aged 20-60 years as measured by magnetic resonance imaging. A descriptive approach

Capturing the cervical spine shape: Angular measurements versus geometric morphometric methods

The cervical spine manifests a wide shape variation. However, the traditional methods to evaluate the cervical spine curve were never tested against its actual shape. The study's main aim was to determine whether the shape classification of the cervical spine, based on traditional angular measurements, coincides with each other and with the shape captured by the 2D landmark-based geometric morphometric method. The study's second aim was to reveal the associations between the cervical spine shape and the demographic parameters, the head's position, and the spine's sagittal balance. CT scans of the cervical spine of 163 individuals were evaluated to achieve these goals. The shape was assessed by measuring the C2-C7 Cobb angle (CA), the C2-C7 posterior tangent angle (PTA), the curvedness of the arch, and by a 2D landmark-based geometric morphometric method. The position of the head and the sagittal balance of the spine were evaluated by measuring the foramen magnum-C2 Cobb angle (FMCA) and the T1 slope angle (T1SA), respectively. Based on the size of the angle measured, each individual was classified into one of the three cervical 'shape groups' (lordotic, straight, and kyphotic). We found that cervical lordosis was the dominant shape regardless of the measuring methods utilized (46.6%-54.6%), followed by straight neck (28.2%-30.1%), and kyphosis (15.3%-25.2%); however, about a third of the 163 individuals were classified into a different shape group using the CA and PTA methods. The cervical spine angle was sex-independent and age-dependent. The T1SA was significantly correlated with CA and PTA (r = 0.640 and r = 0.585, respectively; p < 0.001). In conclusion, the cervical spine shape evaluation is method-dependent and varies with age.

Patients having surgery for ulnar nerve compression at the elbow rarely have affection of the spinal nerve root at C8-Th1 levels

Cervical pathology may contribute to residual problems after surgery for ulnar nerve compression. We aimed to evaluate the presence of pathological conditions in spinal cord and cervical spinal nerve roots in patients surgically treated for ulnar nerve compression at elbow. In a cohort of patients, surgically treated for ulnar nerve compression at elbow, magnetic resonance images (MRI; performed 3 years pre/postoperatively) were evaluated by a neuroradiologist blinded to patient characteristics and outcome of surgery. Cervical conditions were assessed and related to patient characteristics, preoperative McGowan grade, and outcome. Among 62 patients (45 unilaterally and 17 bilaterally), only one had spinal nerve root affection of nerve roots contributing to the ulnar nerve (C8-Th1). About half of the patients, mainly those at higher age, had alterations affecting C3-C7 spinal nerve roots at both surgically treated and contralateral, non-surgically treated, sides. Only few other changes were observed at cervical levels. A high McGowan grading was related to a high frequency of spinal nerve root affection. Smokers were more frequently observed among those with spinal nerve root affection at C3-C7 levels at surgically treated side. Residual problems, expressed as patient dissatisfaction and DASH score ≥40, were common. Spinal nerve roots, contributing to the ulnar nerve, are rarely affected in surgically treated patients with ulnar nerve compression at elbow even though pathology is often observed at other cervical levels. Pathology is often detected at other cervical spinal nerve root levels at surgically treated and contralateral sides, particularly among older patients, smokers, and in conjunction with worse preoperative McGowan grade. No relation between cervical pathology and outcome of ulnar nerve surgery is seen.

Intervertebral Foramen Width Is an Important Factor in Deciding Additional Uncinate Process Resection in ACDF-a Retrospective Study

Background: Anterior cervical discectomy and fusion (ACDF) has been established as a classic procedure for the management of cervical radiculopathy. However, it is unclear whether combined uncinate process resection (UPR) is necessary for treating cervical radiculopathy. Here, we investigated the clinical outcome of ACDF combined with UPR compared to ACDF alone to determine the necessity of UPR in treating cervical radiculopathy. Hypothesis: Uncinate process resection may be necessary in certain patients along with ACDF to achieve better clinical outcomes of cervical radiculopathy. Patients and Methods: Fifty-five patients underwent ACDF with UPR, and 126 patients without UPR were reviewed. The width and height of the intervertebral foramen were measured by 45° oblique X-rays. We also measured the Japanese Orthopedic Association (JOA) score and visual analog scale (VAS) score. C2-C7 Cobb angles were obtained from all patients pre- and post-operatively. Meanwhile, linear regression analysis was used to evaluate the relationship between the clinical outcomes and the intervertebral foramen width before surgery. Results: Linear regression analysis indicated that the improvement in the JOA and VAS scores was irrelevant to both the pre-operative width of the intervertebral foramen (wIVF) and the height of the intervertebral foramen (hIVF) in the ACDF+UPR group. However, pre-operative wIVF was associated with post-operative JOA and VAS scores in the ACDF alone group. Those with pre-operative wIVF <3 mm in the ACDF group had the least improvement in post-operative clinical symptoms due to the change in wIVF (P > 0.05). The ACDF group whose wIVF was over 3 mm showed similar clinical outcomes to the ACDF + UPR group, and wIVF significantly increased post-operatively (P < 0.05). The fusion rate and C2-C7 Cobb angles did not show significant differences between the two groups (P > 0.05). Discussion: Our current findings suggest that UPR should be considered when wIVF is <3 mm pre-operatively. However, there is no need to sacrifice the uncovertebral joint in ACDF when the pre-operative wIVF is over 3 mm. Level of Evidence: Level III.

Cervical disc degeneration: important considerations for the manual therapist

Cervical disc degeneration (CDD) is a progressive, age-related occurrence that is frequently associated with neck pain and radiculopathy. Consistent with the majority of published clinical practice guidelines (CPG) for neck pain, the 2017 American Physical Therapy Association Neck Pain CPG recommends cervical manipulation as an intervention to address acute, subacute, and chronic symptoms in the 'Neck Pain With Mobility Deficits' category as well for individuals with 'Chronic Neck Pain With Radiating Pain'. While CPGs are evidence-informed statements intended to help optimize care while considering the relative risks and benefits, these guidelines generally do not discuss the mechanical consequences of underlying cervical pathology nor do they recommend specific manipulation techniques, with selection left to the practitioner's discretion. From a biomechanical perspective, disc degeneration represents the loss of structural integrity/failure of the intervertebral disc. The sequelae of CDD include posterior neck pain, segmental hypermobility/instability, radicular symptoms, myelopathic disturbance, and potential vascular compromise. In this narrative review, we consider the mechanical, neurological, and vascular consequences of CDD, including information on the anatomy of the cervical disc and the mechanics of discogenic instability, the anatomic and mechanical basis of radiculitis, radiculopathy, changes to the intervertebral foramen, the importance of Modic changes, and the effect of spondylotic hypertrophy on the central spinal canal, spinal cord, and vertebral artery. The pathoanatomical and biomechanical consequences of CDD are discussed, along with suggestions which may enhance patient safety.

Reconstruction of anatomy and care provisioning in a severe case of spondyloepiphyseal dysplasia

OBJECTIVE

This analysis aims to clinically and socially contextualize a set of human remains (TBK Br8) with severe systemic skeletal dysmorphology from Tashbulak, Uzbekistan (8th-11th c. Common Era [CE]).

MATERIALS

One well-preserved and nearly-complete human skeleton.

METHODS

Remains were assessed and documented macroscopically.

RESULTS

Endochondrally derived skeletal elements in TBK Br8 were observed to be underdeveloped. Extensive proliferation of bone had invaded all but one observable joint, variably occluding most intervertebral foramina, the lumbar vertebral canal, and transverse foramina of the cervical spine.

CONCLUSIONS

The remains were diagnosed with spondyloepiphyseal dysplasia (SED), possibly the subtype progressive pseudorheumatoid dysplasia (spondyloepiphyseal dysplasia tarda with progressive arthropathy. Rendered functionally paraplegic by the time of death, TBK Br8 likely suffered from widespread areas of numbness, tingling, weakness and/or pain in the lower limbs and thorax, and perhaps transient psychological symptoms.

SIGNIFICANCE

The severity of TBK Br8's disease would have had significant implications to their daily interactions in a society with deep roots in nomadic lifeways, and is a testament to the care required to enable survival.

LIMITATIONS

Radiology, genetic, and histologic analyses are unavailable.

SUGGESTIONS FOR FUTURE RESEARCH

Focused genetic testing for mutations previously shown to be associated with spondyloepiphyseal dysplasias.

Virtual morphometric method using seven cervical vertebrae for sex estimation on the Turkish population

Sex estimation from skeletal remains is crucial for the estimation of the biological profile of an individual. Although the most commonly used bones for means of sex estimation are the pelvis and the skull, research has shown that acceptable accuracy rates might be achieved by using other skeletal elements such as vertebrae. This study aims to contribute to the development of sex estimation standards from a Turkish population through the examination of CT scans from the seven cervical vertebrae. A total of 294 individuals were included in this study. The CT scans were obtained from patients attending the Bakirkoy Training and Research Hospital (Turkey) and the data was collected retrospectively by virtually taking measurements from each cervical vertebrae. The full database was divided into a training set (N = 210) and a validation set (N = 84) to test the fit of the models. Observer error was assessed through technical error of measurement and sex differences were explored using parametric and non-parametric approaches. Logistic regression was applied in order to explore different combinations of vertebral parameters. The results showed low intra- and inter-observer errors. All parameters presented statistically significant differences between the sexes and a total of 15 univariate and multivariate models were generated producing accuracies ranging from a minimum of 83.30% to a maximum of 91.40% for a model including three parameters collected from four vertebrae. This study presents a virtual method using cervical vertebrae for sex estimation on the Turkish population providing error rates comparable to other metric studies conducted on the postcranial skeleton. The presented results contribute not only to the development of population-specific standards but also to the generation of virtual methods that can be tested, validated, and further examined in future forensic cases.

Dynamic foraminal dimensions during neck motion 6.5 years after fusion and artificial disc replacement

Objective

To compare changes in foraminal motion at two time points post-surgery between artificial disc replacement (ADR) and anterior cervical discectomy and fusion (ACDF).

Methods

Eight ACDF and 6 ADR patients (all single-level C5-6) were tested at 2 years (T1) and 6.5 years (T2) post-surgery. The minimum foraminal height (FH.Min) and width (FW.Min) achieved during neck axial rotation and extension, and the range of these dimensions during motion (FH.Rn and FW.Rn, respectively) were measured using a biplane dynamic x-ray system, CT imaging and model-based tracking while patients performed neck axial rotation and extension tasks. Two-way mixed ANOVA was employed for analysis.

Results

In neck extension, significant interactions were found between year post-surgery and type of surgery for FW.Rn at C5-6 (p<0.006) and C6-7 (p<0.005), and for FH.Rn at C6-7 (p<0.01). Post-hoc analysis indicated decreases over time in FW.Rn for ACDF (p<0.01) and increases in FH.Rn for ADR (p<0.03) at the C6-7 adjacent level. At index level, FW.Rn was comparable between ACDF and ADR at T1, but was smaller for ACDF than for ADR at T2 (p<0.002). In axial rotation, differences were found between T1 and T2 but did not depend on type of surgery (p>0.7).

Conclusions

Changes were observed in the range of foraminal geometry at adjacent levels from 2 years to 6.5 years post-surgery that were different between ACDF and ADR for neck extension. These changes are contrary to the notion that motion at adjacent levels continue to increase following ACDF as compared to ADR over the long term.

Correlation of neural foraminal motion after surgical treatment of cervical radiculopathy with long-term patient reported outcomes

Background

Post-surgical changes in adjacent segment motion are considered a factor in further development of degeneration and cervical radiculopathy. The objective was to examine the extent of correlations between physiological motion of cervical foramina and long-term patient reported outcomes (PRO).

Methods

Biplane X-ray imaging and CT-based markerless tracking were used to measure 3D static and dynamic dimensions during neck axial rotation and extension from 18 patients treated for C5-6 radiculopathy with fusion or arthroplasty. Minimum foraminal height (FH.Min) and width (FW.Min), and their range (FH.Range and FW.Range) achieved during a motion task were calculated for adjacent levels (C4-5 and C6-7) at 2.0±0.6 years post-surgery. The modified Japanese Orthopedic Association score (mJOAS), the Neck Disability Index (NDI) including the visual analogue scale (VAS) for neck and arm pain, and the EuroQol EQ-5D score were recorded at 6.5±1.1 years post-surgery. The relationships between 6.5-year outcomes and 2-year foraminal motion were examined using regression.

Results

Worsening patient-reported outcomes were generally associated with lower values of FW.Min (P<0.05 to P<0.008), the associations being stronger for neck extension (r² up to 0.43). Dynamic foraminal measurements from the C6-7 level more significantly and consistently correlated with mJOAS, EQ-5D and NDI Arm Pain VAS (r²=0.27 to 0.43; P<0.03 to P<0.008), whereas those from the C4-5 level correlated with NDI Neck Pain VAS (r²=0.33; P<0.02).

Conclusions

Dynamic 3D foraminal dimensions at 2-year post-surgery, notably FW.Min measured in neck extension at adjacent levels, were associated with PRO at 6.5 years post-surgery. These relationships provide insight into the motion related factors in development of pain and loss of function, and may help develop markers or objective outcome measures.

Cross-talk between shoulder and neck pain: an imaging study of association between rotator cuff tendon tears and cervical foraminal stenosis

Rotator cuff tendon tears are prevalent in patients with shoulder pain, the third most common musculoskeletal complaint. As shoulders are largely innervated by cervical nerves, it seems possible that rotator cuff pathology could have an association with cervical spine disorders, although few studies have investigated this possibility. This study aimed to explore the association between rotator cuff tendon tears and cervical radiculopathy (at C5 and C6 levels) in the shoulder pain population.We conducted a retrospective review of a clinical registry of shoulder ultrasound (US) examinations and cervical spine radiographs, recruiting a total of 126 patients with cervical spine radiographs taken within 1 year of US examinations. Foraminal stenosis was grouped into 4 categories: C4/5 intervertebral foramen only, C5/6 intervertebral foramen only, both C4/5 and C5/6 intervertebral foramina, and neither C4/5 nor C5/6 intervertebral foramen. The groups with and without rotator cuff tendon tears were compared for various factors, using the Mann-Whitney U test for continuous variables and the χ test for categorical variables. A multivariate analysis was conducted using a logistic regression model to investigate the association between rotator cuff tendon tears and cervical foraminal stenosis.Patients with rotator cuff tendon tears tended to be older and had more night-time pain. No significant association was identified between rotator cuff tendon tears and cervical foraminal stenosis at C5 and C6 levels. The only factor significantly predicting rotator cuff tendon tears was old age (odds ratio, 1.04; 95% confidence interval: 1.00-1.09).In patients with shoulder or neck pain, no significant association existed between rotator cuff tendon tears and cervical foraminal stenosis (at the C5 and C6 levels). When patients present with undifferentiated shoulder and neck pain, physicians should take a detailed history, perform physical examinations and imaging studies of both the neck and shoulder regions.

Differences in Cross-Sectional Intervertebral Foraminal Area From C3 to C7

STUDY DESIGN

Anatomical comparative study.

OBJECTIVES

Few studies have evaluated foraminal areas in the cervical spine without degenerative changes. The purpose of this study was to determine and compare the mean cross-sectional foraminal areas between the C3/4, C4/5, C5/6, and C6/7 levels while also analyzing specimens for differences between sexes and races.

METHODS

We performed an anatomic study of the intervertebral foramen at 4 levels (C3/4, C4/5, C5/6, C6/7) in 100 skeletally mature osseous specimens. Specimens were selected to obtain equal number of African American and Caucasian males and females (n = 25/group) aged 20 to 40 years at time of death. Foramina were photographed bilaterally with and without a silicone rubber disc. The maximal vertical height and mid-sagittal width of each foramen were digitally measured and the areas were calculated using an ellipse as a model.

RESULTS

The average age at death for all specimens was 30 ± 6 years. The mean cross-sectional area of the C4/5 foramen was significantly smaller compared with the C5/6 (P < .001). C5/6 was significantly narrower than C6/7 (P < .001) foramen with and without disc augmentation. C3/4 was not significantly different from more caudal levels. There was no difference between male and female specimens, while African Americans had smaller foraminal sizes than Caucasians.

CONCLUSIONS

This study provides the largest anatomical reference of the cervical intervertebral foramen. In a mature spine without facet joint hypertrophy or osteophytic changes, the C4/5 foramen was narrower than C5/6, which was narrower than C6/7. Understanding the relative foraminal areas in the nonpathological cervical spine is crucial to understanding degenerative changes as well as the anatomical changes in pathologies that affect the intervertebral foramen.

Study of the Transverse Foramen in the Subaxial Cervical Spine in Korean Patients With Degenerative Changes: An Anatomical Note

Background/Aims

The purpose of this study was to provide anatomical data on the dimensions and location of the subaxial transverse foramen (TF) in relation to surgical landmarks routinely used during anterior cervical procedures.

Methods

A total of 116 patients who underwent preoperative computed tomography (CT) evaluations for degenerative cervical disease were enrolled. Axial and coronal CT images of the cervical vertebrae from C3 to C6 were analyzed to measure interforaminal distance, the TF distance from the anterior and posterior vertebral body margin, TF dimensions, and the TF medial margin from the tip and medial margin of the uncus. Comparative and correlative analyses were also performed according to age, body mass index (BMI), and sex.

Results

All measurement values in male patients were larger than those in their female counterparts. The interforaminal distance gradually increased from C3 to C6. The distance of the TF medial margin from the tip of the uncus was found be above approximately 3 mm in all vertebrae except C6. Correlation analysis revealed that age had a significant negative relationship with the transverse diameter of TF. In contrast, BMI had a significant positive correlation with interforaminal distance. Moreover, the distances of the TF medial margin from the tip and medial margin of the uncus showed strong negative correlations with age.

Conclusion

Useful morphometric data were obtained that may help the operating surgeon to avoid vertebral artery injury. The safe distance from the tip of the uncus to the TF medial margin was found to be approximately 3 mm, and this distance should not be violated during lateral decompression. In addition, this value may decrease with age.

Influences of different lower cervical bone graft heights on the size of the intervertebral foramen: multiple planar dynamic measurements with laser scanning

The aim of this study is to evaluate the influences of different bone graft heights on the size of the intervertebral foramen, which will help determine the optimal graft height in clinical practice. Six fresh adult cadavers were used, with the C5-C6 vertebral column segment defined as the functional spinal unit (FSU). After discectomy, the C5/6 intervertebral height was set as the baseline height (normal disc height). We initially used spiral computed tomography (CT) to scan and measure the middle area of the intervertebral foramen when at the baseline height. Data regarding the spatial relationship of C5-C6 were subsequently collected with a laser scanner. Grafting with four different sized grafts, namely, grafts of 100, 130, 160, and 190% of the baseline height, was implanted. Moreover, we scanned to display the FSU in the four different states using Geomagic8.0 studio software. Multiple planar dynamic measurements (MPDM) were adopted to measure the intervertebral foramen volume, middle area, and areas of internal and external opening. MPDM with a laser scanner precisely measured the middle area of the intervertebral foramen as spiral CT, and it is easy to simulate the different grafts implanted. With the increase of the bone graft height, the size of the intervertebral foramen began to decrease after it increased to a certain point, when grafts of 160% of the baseline height implanted. MPDM of the intervertebral foramens with laser scanning three-dimensional (3D) reconstitution are relatively objective and accurate. The recommended optimal graft height of cervical spondylosis is 160% of the mean height of adjacent normal intervertebral spaces.

Demographic aspects in cervical vertebral bodies' size and shape (C3-C7): a skeletal study

BACKGROUND CONTEXT

This cross-sectional study was conducted on the skeletal remains of individuals of known sex, age, and ethnic origin. The vertebral bodies of levels C3-C7 were measured and analyzed. Whereas many studies were performed on the size and shape of the vertebral bodies in the thoracic and lumbar spines, few have focused on the cervical vertebral bodies. Thus, there is insufficient data in the literature on the anatomy of the cervical spine, especially based on large study populations.

PURPOSE

To establish a large database on cervical vertebral bodies' size and shape and analyze their association with demographic parameters.

STUDY DESIGN

The population studied was composed of 277 individuals, adult males and females of African American (AA) and European American (EA) origin. The skeletal remains are housed at the Hamman-Todd Osteological collection (Cleveland Museum of Natural History, Cleveland, OH).

METHODS

A 3-D digitizer was used to measure the size and shape of the C3-C7 vertebral bodies. Descriptive statistics were carried out for all measurements. t Test and one-way analysis of variance were performed to assess differences in vertebral bodies' size and shape between different demographical groups (by age, sex, and ethnicity).

RESULTS

The vertebral bodies and foramina are significantly wider, more elongated, and higher in males compared to females. AA females and males manifest significantly greater vertebral bodies (width and length) in the upper and midcervical region (vertebrae C3-C5) than EA females and males. Nevertheless, the heights of the C3 and C4 vertebral bodies are significantly smaller among the AA population, regardless of sex. The vertebral foramina's width does not differ significantly between the two ethnic groups, independent of sex, whereas they tend to be elongated in the EA group (significant for C3, C5, C7). For most vertebrae, no significant differences were found in the superior facets' length between AA and EA males and females. Cervical vertebral bodies become wider and more elongated with age, although the changes in the latter dimension are much more pronounced than in the former. Notably, the body shape of the cervical vertebrae changes gradually from a more round shape (C3 length/width index=0.84) to a more oval one (C7 length/width index =0.65). This is due to the fact that the width dimensions increase by almost 40% from C3 to C7, whereas the length dimensions increase only by approximately 10%. Furthermore, there is a significant reduction in body height with age in C3-C6. In contrast, no significant changes in vertebral foramen size with age were found.

CONCLUSIONS

The cervical vertebral bodies' shape and size are sex-dependent phenomena, that is, in all parameters studied, the dimensions were greater in males than in females. For the midcervical level, there is a difference in body shape between individuals of different ethnic origins. The cervical vertebral bodies also exhibit considerable size and shape changes with age, that is, they become more elongated (oval shaped), wider, and shorter. In contrast, vertebral foramen size is age independent.

Radiologic Changes of Operated and Adjacent Segments after Anterior Cervical Microforaminotomy

Objective

Anterior cervical microforaminotomy (ACMF) is a motion-preserving surgical procedure. The purpose of this study is to assess radiologic changes of operated and adjacent segments after ACMF.

Methods

We retrospectively reviewed 52 patients who underwent ACMF between 1998 and 2008. From X-ray film-based changes, disc height and sagittal range of motion (ROM) of operated and adjacent segments were compared at preoperative and last follow-up periods. Radiological degeneration of both segments was analyzed as well.

Results

The mean follow-up period was 48.2 months. There were 78 operated, 52 upper adjacent, and 38 lower adjacent segments. There were statistically significant differences in the ROM and disc height of operated segment between preoperative and last follow-up periods. However, there were no statistically significant differences in the ROM and disc height of adjacent segment between both periods. Radiological degenerative changes of operated segments were observed in 30%. That of adjacent segments was observed in 11 and 11% at upper and lower segments, respectively.

Conclusion

After mean 4-year follow-up periods, there were degenerative changes of operated segments. However, ACMF preserved motion and prevented degenerative changes of adjacent segments.

Adolescent Disc Degeneration - No Headache Association

The objective of the study was to determine whether adolescents with headache have more disc degeneration in the cervical spine than headache-free controls. This study is part of a population-based follow-up study of adolescents with and without headache. At the age of 17 years, adolescents with headache at least three times a month ( N = 47) and adolescents with no headache ( N = 22) participated in a magnetic resonance imaging (MRI) study of the cervical spine. Of the 47 headache sufferers, 17 also had weekly neck pain and 30 had neck pain less than once a month. MRI scans were interpreted independently by three neuroradiologists. Disc degeneration was found in 67% of participants, with no difference between adolescents with and without headache. Most of the degenerative changes were located in the lower cervical spine. In adolescence, mild degenerative changes of the cervical spine are surprisingly common but do not contribute to headache.

Dimensional changes of the neuroforamina in subaxial cervical spine during in vivo dynamic flexion-extension

BACKGROUND CONTEXT

Neuroforaminal stenosis is one of the key factors causing clinical symptoms in patients with cervical radiculopathy. Previous quantitative studies on the neuroforaminal dimensions have focused on measurements in a static position. Little is known about dimensional changes of the neuroforamina in the cervical spine during functional dynamic neck motion under physiological loading conditions.

PURPOSE

This study aimed to investigate the in vivo dimensional changes of the neuroforamina in human cervical spine (C3-C7) during dynamic flexion-extension neck motion.

STUDY DESIGN

A case-control study was carried out.

METHODS

Ten asymptomatic subjects were recruited for this study. The cervical spine of each subject underwent magnetic resonance image scanning for construction of three-dimensional (3-D) vertebrae models from C3 to C7. The cervical spine was then imaged using a dual fluoroscopic system while the subject performed a dynamic flexion-extension neck motion in a sitting position. The 3-D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral motion. The dimensions (area, height, and width) were measured for each cervical neuroforamen (C3/C4, C4/C5, C5/C6, and C6/C7) in the following functional positions: neutral position, maximal flexion, and maximal extension. Repeated measures analysis of variance and post hoc analysis were used to examine the differences between levels and positions.

RESULTS

Compared with the neutral position, almost all dimensional parameters (area, height, and width) of the subaxial cervical neuroforamina decreased in extension and increased in flexion, except the neuroforaminal area at C5/C6 (p=.07), and the neuroforaminal height at C6/C7 (p=.05) remained relatively constant from neutral to extension. When comparisons of the overall change fromextension to flexion were made between segments, the overall changes of the neuroforaminal area and height revealed no significant differences between segments, and the width overall change of the upper levels (C3/C4 and C4/C5) was significantly greater than the lower levels (C5/C6 and C6/C7) (p<.01).

CONCLUSIONS

The dimensional changes of the cervical neuroforamina showed segment-dependent characteristics during the dynamic flexion-extension. These data may have implications for diagnosis and treatment of patients with cervical radiculopathy.

Dimensions of the cervical neural foramen in conditions of spinal deformity: an ex vivo biomechanical investigation using specimen-specific CT imaging

PURPOSE

Patients with cervical spondylosis commonly present with neck pain, radiculopathy or myelopathy. As degenerative changes progress, multiple factors including disc height loss, thoracic kyphosis, and facetogenic changes can increase the risk of neural structure compression. This study investigated the impact of cervical deformity including forward head posture (FHP) and upper thoracic kyphosis, on the anatomy of the cervical neural foramen.

METHODS

Postural changes of 13 human cervical spine specimens (Occiput-T1, age 50.6 years; range 21-67) were assessed in response to prescribed cervical sagittal malalignments using a previously reported experimental model. Two characteristics of cervical sagittal deformities, C2-C7 sagittal vertical alignment (SVA) and sagittal angle of the T1 vertebra (T1 tilt), were varied to create various cervical malalignments. The postural changes were documented by measuring vertebral positions and orientations. The vertebral motion data were combined with specimen-specific CT-based anatomical models, which allowed assessments of foraminal areas of subaxial cervical segments as a function of increasing C2-C7 SVA and changing T1 tilt.

RESULTS

Increasing C2-C7 SVA from neutral posture resulted in increased neural foraminal area in the lower cervical spine (largest increase at C4-C5: 13.8 ± 15.7 %, P < 0.01). Increasing SVA from a hyperkyphotic posture (greater T1 tilt) also increased the neural foraminal area in the lower cervical segments (C5-C6 demonstrated the largest increase: 13.4 ± 9.6 %, P < 0.01). The area of the cervical neural foramen decreased with increasing T1 tilt, with greater reduction occurring in the lower cervical spine, specifically at C5-C6 (-8.6 ± 7.0 %, P < 0.01) and C6-C7 (-9.6 ± 5.6 %, P < 0.01).

CONCLUSION

An increase in thoracic kyphosis (T1 tilt) decreased cervical neural foraminal areas. In contrast, an increase in cervical SVA increased the lower cervical neural foraminal areas. Patients with increased upper thoracic kyphosis may respond with increased cervical SVA as a compensatory mechanism to increase their lower cervical neural foraminal area.

Clinical anatomy and significance of the thoracic intervertebral foramen: A cadaveric study and review of the literature

INTRODUCTION

The literature is lacking information on the anatomy and the osseous dimensions of the thoracic intervertebral foramen (IVF). We describe the anatomy of the broader area, and we proceed with morphometric data of the vertebrae and the foramina. Depiction of these features is provided with imaging and illustrations. The purpose of this paper is to survey and present the anatomy of the foramen as a whole and provide baseline statistical data.

MATERIALS AND METHODS

We review relevant literature, and we present data obtained from skeletal samples of known population and sex. One hundred and nineteen thoracic vertebrae of ten cadaveric spines from the prefecture of Eastern Macedonia and Thrace, Greece, were selected. Statistical analysis measuring the vertical height and the foraminal width of each vertebra was made in accordance with sex.

RESULTS

No statistically important differences referring to the descriptive data of both sexes were found. However, statistically, important positive correlation between the vertebral height and the foraminal width was observed, especially for men. The components of the foramen including arteries and veins passing through or neighboring it, and the spinal nerves and roots are described and depicted.

CONCLUSIONS

The osseous thoracic IVF reveals a glimpse of the in vivo structure and alterations of its width may be present in back pain and other degenerative diseases. Although it is crucial for surgeries and other interventional procedures of the thoracic spine, little is known about the precise anatomy and dimensions of this anatomical landmark.

A New MRI Grading System for Cervical Foraminal Stenosis Based on Axial T2-Weighted Images

OBJECTIVE

The purpose of this study was to evaluate the reliability of a new magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (NFS).

MATERIALS AND METHODS

Cervical NFS at bilateral C4/5, C5/6, and C6/7 was classified into the following three grades based on the T2-weighted axial images: Grade 0 = absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root (EFNR); Grade 1 = the narrowest width of the neural foramen the same or less than (but more than 50% of) the width of the EFNR; Grade 2 = the width of the neural foramen the same or less than 50% of the width of the EFNR. The MRIs of 96 patients who were over 60 years old (M:F = 50:46; mean age 68.4 years; range 61-86 years) were independently analyzed by seven radiologists. Interobserver and intraobserver agreements were analyzed using the percentage agreement, kappa statistics, and intraclass correlation coefficient (ICC).

RESULTS

For the distinction among the three individual grades at all six neural foramina, the ICC ranged from 0.68 to 0.73, indicating fair to good reproducibility. The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement. The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.

CONCLUSION

The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.

Cervical Spine Disc Deformation During In Vivo Three-Dimensional Head Movements

Although substantial research demonstrates that intervertebral disc cells respond to mechanical signals, little research has been done to characterize the in vivo mechanical environment in the disc tissue. The objective of this study was to estimate cervical disc strain during three-dimensional head movements. Twenty-nine young healthy adults performed full range of motion flexion/extension, lateral bending, and axial rotation of the head within a biplane radiography system. Three-dimensional vertebral kinematics were determined using a validated model-based tracking technique. A computational model used these kinematics to estimate subject-specific intervertebral disc deformation (C3-4 to C6-7). Peak compression, distraction and shear strains were calculated for each movement, disc level, and disc region. Peak compression strain and peak shear strain were highest during flexion/extension (mean ± 95% confidence interval) (32 ± 3 and 86 ± 8%, respectively), while peak distraction strain was highest during lateral bending (57 ± 5%). Peak compression strain occurred at C4-5 (33 ± 4%), while peak distraction and shear strain occurred at C3-4 (54 ± 8 and 83 ± 11%, respectively). Peak compression, distraction, and shear strains all occurred in the posterior-lateral annulus (48 ± 4, 80 ± 8, and 109 ± 12%, respectively). These peak strain values may serve as boundary conditions for in vitro loading paradigms that aim to assess the biologic response to physiologic disc deformations.

Concomitance of fibromyalgia syndrome and cervical disc herniation

[Purpose] Fibromyalgia syndrome (FMS) and cervical disc herniation (CDH) are a common diseases commonly encountered in physical therapy clinics. There are also patients who have both of these diseases. In this study we aim to investigated whether FMS is a risk factor for cervical disc herniation and the frequency of their coincident occurrence. [Subjects and Methods] Thirty-five patients having a primary FMS diagnosis according to the American Rheumatism Association criteria are taken into consideration and a control group were the subjects of this study. The two groups were compared with respect to cervical disc hernia using cervical region MRI. [Results] The distribution of disc hernia of 6 fibromyalgia patients who had cervical discopathy was: 16.6% C2–3, 16.6% C5–6, 16.6% C6–7, 33.3% C4–5, C5–6 (two levels in two patients) and 16.6% C4–5, C5–6, C7–1 (three levels in one patient) . The herniation directions were given as: central in 5 levels, right paramedian in 1 level, and left paramedian disc hernia in 1 level. There were 4 cervical disk hernia in the control group. The herniation direction were central in two, right paramedian in one, and left paramedian in one patient. [Conclusion] In this study, the existence of cervical disc herniation in fibromyalgia patients was found to be not different from the normal population.

Diagnostic value of oblique magnetic resonance images for evaluating cervical foraminal stenosis

BACKGROUND CONTEXT

The benefits of oblique magnetic resonance imaging (MRI) reformations to assess cervical neural foramina have been reported previously in clinical and cadaveric studies. But there is a paucity of literature investigating intra- and interobserver variabilities for assessing cervical foraminal stenosis using oblique MRI views.

PURPOSE

To determine the value of oblique MRI views compared with axial and sagittal views for assessing foraminal stenosis of the cervical spine using intra- and interobserver variabilities.

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

Twenty-six patients were included.

OUTCOME MEASURES

Two independent reviewers blindly identified the presence of foraminal stenosis as definite or indeterminate on the sagittal, axial, and oblique views. The assessments using the different views were compared using an independent t test. Intra- and interobserver variabilities were assessed using Kappa analysis.

METHODS

We evaluated the cervical spine MRIs of patients with varying degrees of foraminal stenosis. The mean age of the patients was 60.8 years (range 50-86 years). Male to female ratio was 16:10. The oblique images were obtained by reformatting the scans perpendicular to the long axis of the right and left neural foramina, respectively.

RESULTS

The oblique or axial views had significantly greater confidence rates for determining the presence of foraminal stenosis than the sagittal views (92.3%, 88.1% vs. 58.0%, respectively, p=.000). The oblique view had significantly better intraobserver agreement than the sagittal and axial images. Both the axial and oblique views had significantly better interobserver agreement than the sagittal images.

CONCLUSIONS

Oblique MRI views of the cervical spine significantly reduce the degree of intra- and interobserver variabilities and increase observer confidence in the assessment of foraminal stenosis. Our results suggest that routine use of oblique cervical MRI views might be useful for evaluating cervical foraminal stenosis.

Clinical Outcomes After Cervical Transcorporeal Microdecompression and Vertebral Body Access Channel Repair

BACKGROUND

Although anterior cervical decompression and fusion (ACDF) can be performed using minimally invasive techniques, the extensive removal of anatomical keystones during decompression requires a segmental fusion to restore biomechanical stability. Treatment with arthrodesis techniques may result in a prolonged recovery time, loss of motion, and the need for further treatment if a pseudarthosis or adjacent segment disease occur. Transcorporeal micro decompression (TCMD) is a newly developed motion sparing, minimally invasive anterior cervical spine decompression procedure that utilizes a small channel through the cervical vertebral body to decompress areas of central or foraminal stenosis while preserving the native disc. Cervical decompression with TCMD can be performed as a stand-alone or hybrid procedure with ACDF at the adjacent levels. This study retrospectively assesses patient based clinical outcome measures in patients treated with TCMD.

METHODS

A retrospective, non-randomized, single-center chart review of single surgeon experience with patients undergoing TCMD both with and without adjacent level ACDF using both a trajectory control guide and access channel repair. Statistical analyses were performed on pre and post-operative data collected using visual analog scale (VAS) and neck disability index (NDI) outcome measures.

RESULTS

Among 62 patients, there were no cases of neurovascular injury, CSF leak, transfusion, or migration of repair implement. Revision surgery was required in 6.4% (n=4) patients. A subanalysis of outcome metrics was performed for patients that underwent standalone TCMD (TCMD group, n=42) and TCMD with concurrent ACDF at one or more levels (TCMD+ACDF group, n=20). TCMD group NDI improved from 20.0 to 2.7 at 1 year (p=0.0001); Axial VAS improved from 5.5 to 0.6 (p=0.0001); and Radiating VAS improved from 7.0 to 0.7 (p=0.0001). TCMD+ACDF group NDI improved from 22.0 to 4.0 at 1 year (p=0.004); Axial VAS improved from 7.1 to 1.2 (p=0.01); and Radiating VAS trended towards significant improvement from 6.4 to 2.3 (p=0.09). Mean return to work was 10 days in the TCMD group and 57 days in the TCMD+ACDF group.

CONCLUSIONS

Within the limits of a retrospective, single-surgeon study, patients did experience both functional improvement and pain relief as measured by NDI and VAS respectively from standalone TCMD or combined ACDF / TCMD procedures. Definitive statements on long-term efficacy, disc space preservation, and motion preservation await further study.

Comparison of 2 manual therapy and exercise protocols for cervical radiculopathy: a randomized clinical trial evaluating short-term effects

STUDY DESIGN

Participant- and assessor-blinded randomized clinical trial.

OBJECTIVES

To compare a rehabilitation program thought to increase the size of the intervertebral foramen (IVF) of the affected nerve root to a rehabilitation program that doesn't include any specific techniques thought to increase the size of the IVF in patients presenting with cervical radiculopathy (CR).

BACKGROUND

Clinical approaches for the treatment of CR commonly include exercises and manual therapy techniques thought to increase the size of the IVF, but evidence regarding the effectiveness of these specific manual therapy techniques is scarce.

METHODS

Thirty-six participants with CR were randomly assigned either to a group that received a manual therapy and exercise program aimed at increasing the size of the IVF of the affected nerve root (experimental group, n=18) or to a group that received a manual therapy and exercise program without the specific goal of increasing the size of the IVF of the affected level and side (comparison group, n=18). Primary (Neck Disability Index) and secondary (shortened version of the Disabilities of the Arm, Shoulder and Hand questionnaire [QuickDASH] and numeric pain-rating scale) outcomes were evaluated at baseline, at the end of the 4-week program (week 4), and 4 weeks later (week 8). A mixed-model, 2-way analysis of variance was used to analyze treatment effects.

RESULTS

No significant group-by-time interaction or group effect was observed for Neck Disability Index, QuickDASH, and numeric pain-rating scale scores (P≥.14) following the intervention. However, both groups showed statistically and clinically significant improvement from baseline to week 4 and to week 8 in Neck Disability Index, QuickDASH, and numeric pain-rating scale scores (P<.05).

CONCLUSION

Results suggest that manual therapy and exercises are effective in reducing pain and functional limitations related to CR. The addition of techniques thought to increase the size of the IVF of the affected nerve root yielded no significant additional benefits. Given the absence of a "no treatment" group, a spontaneous resolution of symptoms cannot be excluded. However, the magnitude of improvement makes spontaneous resolution unlikely. The trial was registered at ClinicalTrials.gov (NCT01500044).

LEVEL OF EVIDENCE

Therapy, level 1b-.

Cervical spondylomyelopathy in Great Danes: a magnetic resonance imaging morphometric study

Morphometric investigations comparing normal and affected animals increase our understanding of spinal diseases in dogs. The aim of this study was to generate morphometric data for osseous-associated cervical spondylomyelopathy (CSM) in Great Danes (GDs). Magnetic resonance imaging (MRI) morphometric features of the cervical vertebral column of GDs with and without clinical signs of CSM were characterized and compared. Thirty client-owned GDs were prospectively enrolled, including 15 clinically normal and 15 CSM-affected GDs. All dogs underwent MRI of the cervical to thoracic vertebral column (C2-C3 through T1-T2). Areas of the cranial and caudal articular processes, and the height, width and areas of the vertebral canal and spinal cord were determined. Middle foraminal heights were measured. Intervertebral disc width was measured before and after traction. Intraobserver and interobserver agreement were calculated. CSM-affected GDs had larger areas of the caudal articular processes from C2-C3 through T1-T2. In CSM-affected GDs, the vertebral canal and spinal cord areas were significantly smaller at C5-C6 and C6-C7, the vertebral canal width was significantly narrower at C6-C7 and C7-T1, and the spinal cord width was significantly narrower at C5-C6 and C6-C7. Middle foraminal height was smaller in CSM-affected GDs from C3-C4 through C7-T1. Neutral intervertebral disc widths were smaller in CSM-affected GDs. It was concluded that the cervical vertebral canal dimensions are significantly different between normal and CSM-affected GDs. Absolute vertebral canal stenosis and severe foraminal stenosis involving the cervical vertebrae distinguish CSM-affected from clinically normal GDs. These findings are relevant to the pathogenesis of osseous-associated CSM and should be taken into consideration when performing imaging studies and planning surgery.

Adolescent cervical disc degeneration in MRI does not predict adult headache or neck pain: A 5-year follow-up of adolescents with and without headache

AIM

The impact of early degenerative changes of the cervical spine on pain in adulthood is unknown. The objective was to determine whether degeneration in adolescence predicts headache or neck pain in young adulthood.

METHODS

As part of a follow-up of schoolchildren with and without headache, 17-year-old adolescents with headache at least three times a month (N = 47) and adolescents with no headache (N = 22) participated in a magnetic resonance imaging (MRI) study of the cervical spine. The same adolescents were re-examined by phone interview at the age of 22 years (N = 60/69, 87%).

RESULTS

Mild disc degeneration at the age of 17 years was common, but was not associated with either frequent or intensive headache or neck pain at the age of 22 years. Conclusion: Mild degenerative changes of the cervical spine in 17-year-old adolescents cannot be regarded as a cause of future headache or neck pain.

Cervical radiculopathy: study protocol of a randomised clinical trial evaluating the effect of mobilisations and exercises targeting the opening of intervertebral foramen [NCT01500044]

BACKGROUND

Cervical radiculopathy is a common form of neck pain and has been shown to lead to severe disability. Clinical rehabilitation approaches for cervical radiculopathies commonly include exercise and manual therapy interventions targeting the opening of intervertebral foramen, but evidence regarding their effectiveness is scarce. The primary objective of this randomised clinical trial is to compare, in terms of pain and disability, a rehabilitation program targeting the opening of intervertebral foramen to a conventional rehabilitation program, for patients presenting acute or subacute cervical radiculopathies. The hypothesis is that the rehabilitation program targeting the opening of intervertebral foramen will be significantly more effective in reducing pain and disability than the conventional rehabilitation program.

METHODS/DESIGN

This study is a double-blind (participants and evaluators blinded) randomised clinical trial that will allow the comparison of patients with a cervical radiculopathy randomly assigned to one of two groups: one group will receive a 4-week rehabilitation program targeting the opening of intervertebral foramen, and the second group will receive a 4-week conventional rehabilitation program. Thirty-six subjects with cervical radiculopathy will be recruited from participating medical and physiotherapy clinics and will be evaluated at baseline, at the end of the 4-week program and four weeks following the end of the program. The primary outcome measure will be the validated Neck Disability Index questionnaire. Secondary outcome measures will include the short version of the Disabilities of the Arm, Shoulder and Hand questionnaire, a numerical pain rating scale, cervicothoracic mobility and patients' perceived global rating of change. During the 4-week rehabilitation program, each participant will take part in eight physiotherapy treatment sessions (2 session/week) and will perform a home exercise program. A mixed-model, 2-way ANOVA will be used to analyze the effects of the rehabilitation programs.

DISCUSSION

Control trials are needed to define ideal intervention approaches in rehabilitation for this population. This randomised clinical trial will be the first study that directly compares a rehabilitation program targeting the opening of intervertebral foramen to a conventional rehabilitation program for patients with cervical radiculopathy. The results of this study may help to establish best clinical practice guidelines for this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01500044.

Cervical neural space narrowing during simulated rear crashes with anti-whiplash systems

PURPOSE

Chronic radicular symptoms have been documented in whiplash patients, potentially caused by cervical neural tissue compression during an automobile rear crash. Our goals were to determine neural space narrowing of the lower cervical spine during simulated rear crashes with whiplash protection system (WHIPS) and active head restraint (AHR) and to compare these data to those obtained with no head restraint (NHR). We extrapolated our results to determine the potential for cord, ganglion, and nerve root compression.

METHODS

Our model, consisting of a human neck specimen within a BioRID II crash dummy, was subjected to simulated rear crashes in a WHIPS seat (n = 6, peak 12.0 g and ΔV 11.4 kph) or AHR seat and subsequently with NHR (n = 6, peak 11.0 g and ΔV 10.2 kph with AHR; peak 11.5 g and ΔV 10.7 kph with NHR). Cervical canal and foraminal narrowing were computed and average peak values statistically compared (P < 0.05) between WHIPS, AHR, and NHR.

RESULTS

Average peak canal and foramen narrowing could not be statistically differentiated between WHIPS, AHR, or NHR. Peak narrowing with WHIPS or AHR was 2.7 mm for canal diameter and 1.6 mm, 2.7 mm, and 5.9 mm(2) for foraminal width, height and area, respectively.

CONCLUSIONS

While lower cervical spine cord compression during a rear crash is unlikely in those with normal canal diameters, our results demonstrated foraminal kinematics sufficient to compress spinal ganglia and nerve roots. Future anti-whiplash systems designed to reduce cervical neural space narrowing may lead to reduced radicular symptoms in whiplash patients.

Adjacent-level biomechanics after single versus multilevel cervical spine fusion

OBJECT

Previous studies have demonstrated that patients with spinal fusion are at greater risk for adjacent-segment disease and require additional surgery. It has been postulated that excessive motion of a given motion segment unit (MSU) leads to an increased risk of disc degeneration. It is the authors' hypothesis that a greater increase in adjacent-segment motion will be observed following a 2-level versus a single-level anterior cervical discectomy and instrumented fusion (ACDF). Therefore, they undertook this study to determine the effect of single-level versus 2-level ACDF on the biomechanics of adjacent MSUs.

METHODS

Ten fresh-frozen human cervical spines were used in this study. The specimens were potted at C-4 and T-1 and tested in flexion and extension. Range of motion (ROM) was 30° of flexion and 15° of extension at a maximum load of 50 N. The specimens were tested intact and then were randomized into 2 groups of 5 specimens each. Group 1 underwent a single-level ACDF at the C5-6 level first, and Group 2 underwent the procedure at the C6-7 level. After testing, both groups had the fusion extended to include the C5-7 levels, and the testing was repeated. Changes in overall ROM, stiffness, and segmental motion were calculated and statistically analyzed using a paired Student t-test.

RESULTS

An increase in sagittal ROM of 31.30% above (p = 0.012) and 33.88% below (p = 0.066) the fused MSU was found comparing a 2-level with a 1-level ACDF. The overall stiffness of the entire spinal construct increased 37.34% (p = 0.051) in extension and 30.59% (p = 0.013) in flexion as the second fusion level was added. As expected, the overall sagittal ROM of the entire spinal construct decreased by 13.68% (p = 0.0014) with a 2-level compared with a 1-level fusion.

CONCLUSIONS

This study has shown that the biomechanics at adjacent levels to a cervical spine fusion are altered and that there is increased adjacent-segment motion at the levels above and below, after a 2-level compared with a 1-level ACDF.

Changes in the range of motion of the cervical spine and adjacent segments at ≥24 months after uninstrumented corpectomy for cervical spondylotic myelopathy

BACKGROUND

Few clinical studies have described the changes in the range of motion (ROM) of the cervical spine and adjacent segments following central corpectomy. We aimed to quantify the changes in range of motion (ROM) of the cervical spine and the adjacent segments at ≥24 months following uninstrumented central corpectomy (CC) for cervical spondylotic myelopathy (CSM) and to determine the contribution of the adjacent segments to the compensation for loss of motion of the cervical spine following CC.

METHODS

Preoperative and follow-up lateral cervical spine radiographs of 36 patients who underwent CC for CSM between 2001 and 2007 were compared for the ROM of the subaxial cervical spine, superior and inferior adjacent segment. Anterior osteophytes as seen on the radiographs were classified according to Nathan's grading system.

RESULTS

The mean duration of follow-up was 48.5 months. At follow-up, the total cervical spine ROM decreased by 18.3° ± 2.2° (p < 0.001), the superior adjacent segment ROM increased by 2.3° ± 0.9° (p = 0.01) and the inferior adjacent segment ROM, measured in 20 cases, increased by 6.2° ± 1.7° (p = 0.01). The superior adjacent segment showed a 70% increase, whereas the inferior adjacent segment showed a 110% increase in mobility. Nathan's grade at the superior or inferior adjacent segment increased in 12 cases.

CONCLUSIONS

CC significantly reduces the motion of the cervical spine and increases the adjacent segment mobility at intermediate follow-up. The inferior adjacent segment shows greater compensation of motion as compared to the superior adjacent segment in our series. Adjacent segment degeneration as estimated by Nathan's grade was seen in one-third of the cases.

Adjacent segment disease after fusion for cervical spondylosis; myth or reality?

Cervical spondylosis is a common cause of radiculopathy and myelopathy, often treated by discectomy and interbody fusion. However, there has been a recent vogue for the use of artificial disc prostheses to decrease the risk of accelerated degenerative disease at adjacent levels. The short-term results of artificial disc replacements have been encouraging, but the long-term justification for using this new technology hinges on whether the incidence of adjacent segment disease decreases. It will also be necessary to demonstrate that movement at the operated levels is maintained and the incidence of device failure is low. We review the radiological, biomechanical and clinical evidence for adjacent segment disease, and the rationale for using artificial cervical disc replacements. There is presently insufficient evidence to justify the widespread use of artificial disc replacements in the treatment of cervical spondylosis, but neither is there sufficient evidence to criticize their use. Present evidence suggests that adjacent segment disease is partly due to the natural history of spondylotic disease and partly due to cervical fusion. Randomized trials are required to ascertain whether the incidence of adjacent segment disease changes with the use of artificial disc replacements in the long term. Indications for the use of artificial discs are presently unclear, but disc replacements might be recommended for 'young' patients who require an anterior cervical discectomy, with good ranges of neck movements, and an awareness of the satisfactory short-term results, but lack of long-term outcome data, preferably within the limits of a clinical trial.

Changes in the lumbar foramen following anterior interbody fusion with tapered or cylindrical cages

BACKGROUND CONTEXT

Anterior lumbar interbody fusion (ALIF) using both cylindrical and tapered threaded interbody cages has been shown to restore disc height, reduce segmental motion, and relieve low back pain. The effectiveness of these stand-alone cage designs in restoration and maintenance of intervertebral foraminal dimensions has received little attention.

PURPOSE

To investigate the effects of anterior implantation of cylindrical and tapered interbody cages on morphologic changes of the lumbar neuroforamen and maintenance of foraminal dimensions under dynamic loading.

STUDY DESIGN/SETTING

A biomechanical study using bovine calf spine model to compare the deformation of foraminal space after ALIF with either tapered cages or cylindrical cages.

METHODS

Sixteen fresh calf spines were randomly assigned to undergo ALIF at the L3-L4 level using either two threaded cylindrical or two tapered cages. Lumbar spines were subjected to unconstrained loading in flexion, extension, and lateral bending. Rotation of the L3-L4 segment and dynamic deformation in foraminal height were obtained through a motion analysis system, and compared between the two cage groups. Foraminal dimensions were assessed before and after tapered or cylindrical cage implantation with digitized measurement of bilateral foraminal molds.

RESULTS

Regardless of cage design, anterior implantation of cages increased neuroforaminal area by 17% (p=.0005) and increased the foraminal height by 9% (p=.0004) in the neutral unloaded position. In dynamic loading conditions, foraminal height was significantly stabilized in all loading directions by the cylindrical cages (p=.01) and on both sides during lateral bending by the tapered cages (p<.03). Foraminal stabilization provided by either cage was most prominent in the direction of lateral bending (26-37% of the intact values), while cylindrical cages also provided substantial stabilization in flexion (26% of the intact value). Significant linear relationships were found between foraminal height and residual fusion segment motion under dynamic loading conditions.

CONCLUSION

Results from this bovine model biomechanical study indicate that stand-alone anterior interbody fusion cages with either tapered or cylindrical design are effective in restoring neuroforaminal height and stabilize the spine to withstand foraminal deformation during daily loading. The degree of stabilization was influenced substantially by the loading direction, to a lesser degree by the cage type, and was strongly dependent on the segment mobility. Although bovine lumbar spine is widely accepted for comparative studies, direct clinical interpretation should be made with caution owing to the anatomical differences from human.

Morphologic and morphometric magnetic resonance imaging features of Doberman Pinschers with and without clinical signs of cervical spondylomyelopathy

OBJECTIVE

To compare morphologic and morphometric features of the cervical vertebral column and spinal cord of Doberman Pinschers with and without clinical signs of cervical spondylomyelopathy (CSM; wobbler syndrome) detected via magnetic resonance imaging (MRI).

ANIMALS

16 clinically normal and 16 CSM-affected Doberman Pinschers.

PROCEDURES

For each dog, MRI of the cervical vertebral column (in neutral and traction positions) was performed. Morphologically, MRI abnormalities were classified according to a spinal cord compression scale. Foraminal stenosis and intervertebral disk degeneration and protrusion were also recorded. Morphometric measurements of the vertebral canal and spinal cord were obtained in sagittal and transverse MRI planes.

RESULTS

4 of 16 clinically normal and 15 of 16 CSM-affected dogs had spinal cord compression. Twelve clinically normal and all CSM-affected dogs had disk degeneration. Foraminal stenosis was detected in 11 clinically normal and 14 CSM-affected dogs. Vertebral canal and spinal cord areas were consistently smaller in CSM-affected dogs, compared with clinically normal dogs. In neutral and traction positions, the intervertebral disks of CSM-affected dogs were wider than those of clinically normal dogs but the amount of disk distraction was similar between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

The incidence of intervertebral disk degeneration and foraminal stenosis in clinically normal Doberman Pinschers was high; cervical spinal cord compression may be present without concurrent clinical signs. A combination of static factors (ie, a relatively stenotic vertebral canal and wider intervertebral disks) distinguished CSM-affected dogs from clinically normal dogs and appears to be a key feature in the pathogenesis of CSM.

Human osseous intervertebral foramen width

Alterations of the width of the human intervertebral foramen can play a pathophysiological role in low back pain. Osseous dimensions of the human intervertebral foramen are rarely recorded. Therefore, we present reference data obtained from skeletal samples of known lifestyle, population affinity, sex, and age at death. Cervical, thoracic, and lumbar vertebrae of functional transition zones of 71 macroscopically normal spines from early 19th century AD Swiss burial sites were selected. The intervertebral foramen widths (IFW) were analyzed with respect to possible lateralization and the impact of sex, individual age, and stature. Neither a significant side difference nor a correlation of IFW with individual age or stature could be found. Females show somewhat larger IFW than males, especially in the lumbar region. Data comparisons with earlier studies are limited due to methodological differences and possible interpopulational variations. Furthermore, the osseous intervertebral foramen only reveals a glimpse of the clinically relevant in vivo structure. Nevertheless, more focus on the osseous dimensions of the intervertebral foramen will provide baseline data of this important anatomical landmark. These data could also explore the peculiarities of the intervertebral foramen, such as its reverse sex dimorphism.

Head-turned rear impact causing dynamic cervical intervertebral foramen narrowing: implications for ganglion and nerve root injury

OBJECT

A rotated head posture at the time of vehicular rear impact has been correlated with a higher incidence and greater severity of chronic radicular symptoms than accidents occurring with the occupant facing forward. No studies have been conducted to quantify the dynamic changes in foramen dimensions during head-turned rear-impact collisions. The objectives of this study were to quantify the changes in foraminal width, height, and area during head-turned rear-impact collisions and to determine if dynamic narrowing causes potential cervical nerve root or ganglion impingement.

METHODS

The authors subjected a whole cervical spine model with muscle force replication and a surrogate head to simulated head-turned rear impacts of 3.5, 5, 6.5, and 8 G following a noninjurious 2-G baseline acceleration. Continuous dynamic foraminal width, height, and area narrowing were recorded, and peaks were determined during each impact; these data were then statistically compared with those obtained at baseline. The authors observed significant increases (p < 0.05) in mean peak foraminal width narrowing values greater than baseline values, of up to 1.8 mm in the left C5-6 foramen at 8 G. At the right C2-3 foramen, the mean peak dynamic foraminal height was significantly narrower than baseline when subjected to rear-impacts of 5 and 6.5 G, but no significant increases in foraminal area were observed. Analysis of the results indicated that the greatest potential for cervical ganglion compression injury existed at C5-6 and C6-7. Greater potential for ganglion compression injury existed at C3-4 and C4-5 during head-turned rear impact than during head-forward rear impact.

CONCLUSIONS

Extrapolation of present results indicated potential ganglion compression in patients with a non-stenotic foramen at C5-6 and C6-7; in patients with a stenotic foramen the injury risk greatly increases and spreads to include the C3-4 through C6-7 as well as C4-5 through C6-7 nerve roots.

Adjacent level degeneration after anterior cervical fusion: a clinical review

Anterior cervical discectomy and corpectomy for the treatment of cervical spondylosis,cervical disc herniation, and ossification of the posterior longitudinal ligament enjoy favorable rates of fusion and successful clinical outcomes. Although the complications from these procedures have been well described, the pathogenesis and clinical development of adjacent segment degeneration (ASD) are not fully understood. The definition of symptomatic ASD is the development of radicular or myelopathic signs and symptoms referable to a motion segment adjacent to prior cervical arthrodesis. The incidence, pathogenesis, prevalence, and potential treatment strategies for symptomatic ASD are discussed in this article.

Dynamic intervertebral foramen narrowing during simulated rear impact

STUDY DESIGN

A biomechanical study of intervertebral foraminal narrowing during simulated automotive rear impacts.

OBJECTIVES

To quantify foraminal width, height, and area narrowing during simulated rear impact, and evaluate the potential for nerve root and ganglion impingement in individuals with and without foraminal spondylosis.

SUMMARY OF BACKGROUND DATA

Muscle weakness and paresthesias, documented in whiplash patients, have been associated with neural compression within the cervical intervertebral foramen. To our knowledge, no studies have comprehensively examined dynamic changes in foramen dimensions.

METHODS

There were 6 whole cervical spine specimens (average age 70.8 years) with muscle force replication and surrogate head that underwent simulated rear impact at 3.5, 5, 6.5, and 8 g, following noninjurious baseline 2 g acceleration. Peak dynamic narrowing of foraminal width, height, and area were determined during each impact and statistically compared to baseline narrowing.

RESULTS

Significant increases (P < 0.05) in average peak foraminal width narrowing above baseline were observed at C5-C6 beginning with 3.5 g impact. No significant increases in average peak foraminal height narrowing were observed, while average peak foraminal areas were significantly narrower than baseline at C4-C5 at 3.5, 5, and 6.5 g.

CONCLUSIONS

Extrapolation of the present results indicated that the highest potential for ganglia compression injury was at the lower cervical spine, C5-C6 and C6-C7. Acute ganglia compression may produce a sensitized neural response to repeat compression, leading to chronic radiculopathy following rear impact.

Idiopathic Neuralgic Amyotrophy: An Illustrative Case Report

OBJECTIVE

To describe the case of a patient diagnosed with neuralgic amyotrophy (NA) illustrating pertinent aspects of differential diagnosis, the use of clinical neurophysiological procedures to aid in establishing the diagnosis, and issues of management.

CLINICAL FEATURES

A 39-year-old male soldier presented with a rapid onset of marked loss of left shoulder movement. This started acutely early one morning as a sharp, severe lower neck pain progressing over the following 2 weeks to a less severe dull ache in the left shoulder and arm. Pain was rapidly replaced with weakness. Physical examination and electrodiagnostic investigation helped establish a diagnosis of NA.

INTERVENTION AND OUTCOME

The patient was reassured that this is normally a self-limiting condition. Range of motion exercises progressing to a strengthening program was prescribed. He was progressing well; however, we lost contact because of his commitments in the armed service.

CONCLUSION

When a patient presents with shoulder and arm pain of neurogenic origin, NA should be a consideration. Differentiating NA from radiculopathy is especially important in making management decisions. With a careful history and physical examination, the diagnosis may be made without the need for ancillary investigations. Neuralgic amyotrophy is a self-limiting condition requiring reassurance and monitoring.

Symptomatic and asymptomatic abnormalities in patients with lumbosacral radicular syndrome: Clinical examination compared with MRI

OBJECTIVE

To determine the frequency of symptomatic and asymptomatic herniated discs and root compression in patients with lumbosacral radicular syndrome (LRS) and to correlate clinical localization with MRI findings.

METHODS

Fifty-seven patients with unilateral LRS were included in the study. Using the visual analogue scale, two physicians independently localized the most likely lumbar level of complaints. These clinical predictions of localizations were correlated with the MRI findings.

RESULTS

MRI showed abnormalities on the symptomatic side in 42 of 57 patients (74%). In 30% of the patients, MRI confirmed an abnormality at the exact same level as determined after clinical examination. On the asymptomatic side, MRI showed abnormalities in 19 of 57 patients (33%), 13 (23%) of these patients had asymptomatic root compression.

CONCLUSIONS

In more than two-thirds of the patients with unilateral LRS there was no exact match between the level predicted by clinical examination and MRI findings. These discrepancies complicate the decision whether or not to operate.

Effects of unisegmental disc compression on adjacent segments: an in vivo animal model

It is controversial whether fusion of discs in the spine leads to increased degeneration on the remaining discs or whether the degenerative changes are merely a part of the inevitable natural history process. To determine the effects of unisegmental compression and subsequent recovery on adjacent segments, we studied histology, radiology and intradiscal pressure using an in vivo rabbit model. Fifteen New Zealand rabbits were divided in to three groups of five. In the first group, the intervertebral disc L4-L5 of the lumbar spine was axially loaded for 28 days with an external loading device. In the second group, the intervertebral disc was compressed for 28 days and allowed to recover for an equal amount of time, with the loading device removed. Five animals underwent a sham operation, in which the external loading device was situated, but their discs remained unloaded for 28 days. The intradiscal pressure was determined in the loaded discs as well as in the cranial and caudal adjacent discs. Lateral radiographs were taken from each subjected intervertebral disc with adjacent vertebral bodies and the cranial and caudal adjacent segments. The compressed discs showed lower intradiscal pressure in comparison with the control group, which remained unloaded. In the cranial and caudal discs adjacent to the loaded discs the average intradiscal pressure was similar to the unloaded controls. The loaded discs demonstrated a significant decrease in disc space. No discs adjacent to the loaded discs changed in height. The lamellar architecture of the inner, middle, and outer annulus became more disorganized in the loaded discs. The nucleus pulposus showed increase of mucoid degeneration and increased cell death. Intervertebral discs from the control group and the adjacent discs to the compressed discs maintained their normal morphology. This study shows that mechanical loading of discs in the spine can cause rapid degeneration. Adjacent discs, however, did not change in terms of radiology, intradiscal pressure, or histology.

Age-dependent changes of the normal human spine during adulthood

The impact of aging on the morphology of the osseous spine is still debated. Clinical studies usually record combined aging effects, as well as age-related degenerative changes. The aim of this study was to determine the impact of (degeneration-independent) aging on the morphology of the osseous human spine during adulthood. Various osseous dimensions of human spinal landmarks at all major vertebral levels have been assessed in macroscopically normal Swiss skeletons (N = 71), with historically known sex and age at death, as well as in larger Central European skeletal samples (N = 277) with anthropologically determined individual age and sex. All measurements were correlated with individual age (or age group) by linear regression and analyzed separately for each sex. Only few osseous spinal dimensions, and only in men, correlate significantly with individual age. Generally, the significant dimensions show an increase in size during adulthood. Similar tendencies, but with significant alterations of spinal measurements in women as well, can be found in the larger samples with anthropologically determined sex and age group. Increase of certain spinal dimensions found in this study may be a reflection of an increase in the robustness of individuals with age. Because of the absence of a significant secular alteration of stature within the well-recorded sample, we exclude secular change in body dimensions as a major bias.

The effect of posterior cervical distraction on foraminal dimensions utilizing a screw-rod system

STUDY DESIGN

Cadaveric human cervical spine anatomic study using posterior lateral mass screw-rod instrumentation to assess foraminal enlargement via distraction techniques.

OBJECTIVES

To determine the role of posterior cervical distraction on foraminal dimensions and to ascertain the impact of this technique on segmental kyphosis.

SUMMARY OF BACKGROUND DATA

Management of cervical spondylotic radiculopathy includes removal of offending compressive structures and enlarging the neuroforamen via anterior discectomy with interbody fusion or posterior laminoforaminotomy.

METHODS

Six human cervical spines were prepared and posterior exposure performed. Lateral mass screws were inserted from C5 to C7 and a longitudinal rod attached. Distraction was applied between the screw heads at 2 mm intervals and accuracy confirmed with digitized calipers. Pre- and postdistraction computed tomography was performed including axial and reformatted images. Foraminal area, height, and width and sagittal alignment and disc heights were evaluated.

RESULTS

The results suggest that minimal posterior distraction of 4 to 6 mm at C5-C6 and C6-C7 may enlarge the neuroforamen by 10 to 18 mm. Foraminal height and width increased minimally from baseline to maximum distraction; however, these measurements did not reach statistical significance at either level. A decrease of segmental lordosis at C5-C6 was noted from baseline to 8 mm of distraction. Statistically significant kyphosis from baseline was present at 6 mm of distraction leading to overall 5.2 +/- 1.4degrees change in alignment. At C6-C7, statistically significant kyphosis was not present until 8 mm of distraction (4.62 +/- 2.23degrees).

CONCLUSIONS

This study suggests that posterior cervical instrumented distraction in the setting of foraminal stenosis is a reasonable supplement to direct laminoforaminotomy and nerve root decompression. Distraction leads to minimal segmental kyphosis, allowing this technique to serve as an adjunct for additional foraminal enlargement.

Clinical perspectives on secular trends of intervertebral foramen diameters in an industrialized European society

Low back pain origins have been a matter of great controversy. While spinal stenosis is now radiologically traceable, the alteration of intervertebral foramen is less clear. The aim of this study was to assess "secular trends"-alterations occurring from one generation to the next-in osseous intervertebral foramina of the major vertebral segments in an industrialized society, and to discuss their possible clinical implication. The macerated "maximum intervertebral foramen width" and "intervertebral foramen height" of all major vertebral levels in 71 non-pathologic Swiss adult skeletons from the nineteenth and early twentieth century, with known individual age and sex and similar geographic and socio-economic background, were measured by sliding caliper at validated landmarks. A secular trend of the increase in "maximum intervertebral foramen width" is found for most levels, with females showing a more prominent alteration. Additionally, the non-pathologic "maximum intervertebral foramen width" does not change with respect to individual age, nor is a significant side difference detectable. "Intervertebral foramen height," hereby defined as the difference of the dorsal vertebral body height minus pedicle height, demonstrates for most levels, and either sex, an insignificant negative secular trend. Neither stature nor skeletal robustness vary significantly through time within this particular sample. The results of this study, despite obvious inadequacies of methods used, exclude secular narrowing of the "maximum intervertebral foramen width" as the only cause of radiculopathy or spinal stenosis. Furthermore, we found a mild insignificant decrease of the clinically more relevant "intervertebral foramen height." Nevertheless, the detected short-time variability of the bony intervertebral foramen, independent of individual stature, skeletal robustness or age, argues for an enhanced focus on the understanding of clinically relevant changes of spinal morphology from generation to generation.

Cervical radiculopathy treated with chiropractic flexion distraction manipulation: a retrospective study in a private practice setting

BACKGROUND

Although flexion distraction performed to the lumbar spine is commonly utilized and documented as effective, flexion distraction manipulation performed to the cervical spine has not been adequately studied.

OBJECTIVE

To objectively quantify data from the Visual Analogue Scale (VAS) to support the clinical judgment exercised for the use of flexion distraction manipulation to treat cervical radiculopathy.Design and setting A retrospective analysis of the files of 39 patients from a private chiropractic clinic that met diagnostic criteria for inclusion. All patients were diagnosed with cervical radiculopathy and treated by a single practitioner with flexion distraction manipulation and some form of adjunctive physical medicine modality. Main outcome measures The VAS was used to objectively quantify pain. Of the 39 files reviewed, 22 contained an initial and posttreatment VAS score and were therefore utilized in this study.

RESULTS

This study revealed a statistically significant reduction in pain as quantified by visual analogue scores. The mean number of treatments required was 13.2 +/- 8.2, with a range of 6 to 37. Only 3 persons required more treatments than the mean plus 1 standard deviation.

CONCLUSION

The results of this study show promise for chiropractic and manual therapy techniques such as flexion distraction, as well as demonstrating that other, larger research studies must be performed for cervical radiculopathy.