Cervical spondylotic myelopathy (CSM) refers to impaired function of the spinal cord caused by degenerative changes of the cervical spine resulting in spinal cord compression. It is the most common disorder in the United States causing dysfunction of the spinal cord. A literature review of the natural history of mild cervical myelopathy is undertaken. Clinical presentation and current concepts of pathophysiology are also discussed. While many patients with mild signs of CSM will stabilize or improve over time with conservative treatment, the clinical course of a specific individual patient cannot be predicted. Asymptomatic patients with cervical stenosis and abnormalities on electrophysiologic studies may be at higher risk for developing myelopathy.
Cervical spondylotic myelopathy (CSM) is serious consequence of cervical intervertebral disk degeneration. Morbidity ranges from chronic neck pain, radicular pain, headache, myelopathy leading to weakness, and impaired fine motor coordination to quadriparesis and/or sphincter dysfunction. Surgical treatment remains the mainstay of treatment once myelopathy develops. Compared to more conventional surgical techniques for spinal cord decompression, such as anterior cervical discectomy and fusion, laminectomy, and laminoplasty, patients treated with corpectomy have better neurological recovery, less axial neck pain, and lower incidences of postoperative loss of sagittal plane alignment. The objective of this study was to analyze the outcome of corpectomy in cervical spondylotic myelopathy, to assess their improvement of symptoms, and to highlight complications of the procedure.
Materials and Methods:
Twenty-four patients underwent cervical corpectomy for cervical spondylotic myelopathy during June 1999 to July 2005.The anterior approach was used. Each patient was graded according to the Nuricks Grade (1972) and the modified Japanese Orthopaedic Association (mJOA) Scale (1991), and the recovery rate was calculated.
Preoperative patients had a mean Nurick's grade of 3.83, which was 1.67 postoperatively. Preoperative patients had a mean mJOA score of 9.67, whereas postoperatively it was 14.50. The mean recovery rate of patients postoperatively was 62.35% at a mean follow-up of 1 year (range, 8 months to 5 years).The complications included one case (4.17%) of radiculopathy, two cases (8.33%) of graft displacement, and two cases (8.33%) of screw back out/failure.
Cervical corpectomy is a reliable and rewarding procedure for CSM, with functional improvement in most patients.
Cervical corpectomy; cervical spondylotic myelopathy (CSM); cervical decompression; anterior approach
The Trömner sign is commonly used as a clinical neurological examination for upper motor neuron lesions above the fifth or sixth cervical segments of the spinal cord. This study aims to assess and quantify the Trömner signs utilizing electrophysiological test, and correlate to the severity of cord compression in cervical spondylotic myelopathy (CSM). We enlisted 46 CSM patients, and 30 healthy persons as controls. Manual Trömner and Hoffmann signs were tested in all subjects. By using a self-designed instrument, we performed electrophysiological assessments for the Trömner signs in patients and controls. Parameters of conduction latencies and amplitude of muscle action potentials were measured and compared with the cord compression ratios in CSM patients. The results showed a greater diagnostic sensitivity for the quantified Trömner signs in comparison to those of manual Trömner signs and Hoffmann signs. We found a positive correlation between the amplitude of muscle action potentials obtained in the Trömner signs and the cord compression ratios in the patients with CSM. In conclusion, the Trömner signs can be measured by electrophysiological assessments. We demonstrate a new quantification method for an established neurological sign. Not only is Trömner sign a highly sensitive test in clinical neurological examination, the electrophysiological assessment of this sign can also serve as an objective marker for evaluation of the severity of cervical cord compression.
Trömner sign; Neurological reflex; Neurophysiology; Cervical spondylotic myelopathy
This two part series reviews the recent literature concerning the etiology and clinical presentation of cervical spondylotic myelopathy (CSM). CSM is the most common neurological spinal cord disorder after middle age. It is caused by the compromise of the cervical spinal cord from narrowing of the spinal canal.
In Part I, a review of the anatomy and the pathomechanics of the cervical spine pertinent to CSM is discussed. Emphasis is placed upon the intricate relationship between the osseous, neurological and vascular structures. The consequences of degenerative changes upon this relationship is evidenced by the resulting neurovascular compression. In turn, compression may lead to spinal cord ischemia with characteristic clinical results.
cervical spondylotic myelopathy; cervical spine; spondylosis; myelopathy; chiropractic; manipulation
Dilated cardiomyopathy (DCM) is a heterogeneous group of heart diseases with a strong genetic background. Currently, many human DCM cases exist where no causative mutation can be identified. DCM also occurs with high prevalence in several large dog breeds. In the Doberman Pinscher a specific DCM form characterized by arrhythmias and/or echocardiographic changes has been intensively studied by veterinary cardiologists. We performed a genome-wide association study in Doberman Pinschers. Using 71 cases and 70 controls collected in Germany we identified a genome-wide significant association to DCM on chromosome 5. We validated the association in an independent cohort collected in the United Kingdom. There is no known DCM candidate gene under the association signal. Therefore, DCM in Doberman Pinschers offers the chance of identifying a novel DCM gene that might also be relevant for human health.
Herniation of the intervertebral disk is a common cause of neurological dysfunction in the dog, particularly in the Dachshund. Using the Illumina CanineHD BeadChip, we have previously identified a major locus on canine chromosome 12 nucleotide positions 36,750,205–38,524,449 that strongly associates with intervertebral disk calcification in Danish wire-haired Dachshunds. In this study, targeted resequencing identified two synonymous variants in MB21D1 and one in the 5′-untranslated region of KCNQ5 that associates with intervertebral disk calcification in an independent sample of wire-haired Dachshunds. Haploview identified seven linkage disequilibrium blocks across the disease-associated region. The effect of haplotype windows on disk calcification shows that all haplotype windows are significantly associated with disk calcification. However, our predictions imply that the causal variant(s) are most likely to be found between nucleotide 36,750,205–37,494,845 as this region explains the highest proportion of variance in the dataset. Finally, we develop a risk prediction model for wire-haired Dachshunds. We validated the association of the chromosome 12 locus with disk calcification in an independent sample of wire-haired Dachshunds and identify potential risk variants. Additionally, we estimated haplotype effects and set up a model for prediction of disk calcifications in wire-haired Dachshunds based on genotype data. This genetic prediction model may prove useful in selection of breeding animals in future breeding programs.
canine; intervertebral disk calcification; LD pattern; haplotype effects; resequencing
Age-related changes in the spinal column result in a degenerative cascade known as spondylosis. Genetic, environmental, and occupational influences may play a role. These spondylotic changes may result in direct compressive and ischemic dysfunction of the spinal cord known as cervical spondylotic myelopathy (CSM). Both static and dynamic factors contribute to the pathogenesis. CSM may present as subclinical stenosis or may follow a more pernicious and progressive course. Most reports of the natural history of CSM involve periods of quiescent disease with intermittent episodes of neurologic decline. If conservative treatment is chosen for mild CSM, close clinical and radiographic follow-up should be undertaken in addition to precautions for trauma-related neurologic sequelae. Operative treatment remains the standard of care for moderate to severe CSM and is most effective in preventing the progression of disease. Anterior surgery is often beneficial in patients with stenotic disease limited to a few segments or in cases in which correction of a kyphotic deformity is desired. Posterior procedures allow decompression of multiple segments simultaneously provided that adequate posterior drift of the cord is attainable from areas of anterior compression. Distinct risks exist with both anterior and posterior surgery and should be considered in clinical decision-making.
cervical spine; spondylosis; myelopathy; natural history; operative treatment
Two horses with ataxia of all four limbs were found to have cervical intervertebral disc protrusion. Severe pelvic limb ataxia, proprioceptive deficits and spasticity were present in both horses with similar but less severe signs in the thoracic limbs. Cerebrospinal fluid analysis was within normal limits. Metrizamide myelography allowed definitive diagnosis in one case when a compression of the spinal cord was demonstrated at the level of the second intervertebral space. In the second case, an intervertebral disc protrusion between cervical vertebrae 6 and 7 was found at necropsy. Fiber degeneration with poor myelin staining characterized the spinal cords histologically.
A retrospective study.
To evaluate the surgical results of cervical pedicle screw (CPS) fixation combined with laminoplasty for treating cervical spondylotic myelopathy (CSM) with instability.
Overview of Literature
Cervical fixation and spinal cord decompression are required for CSM patients with instability. However, only a few studies have reported on CPS fixation combined with posterior decompression for unstable CSM patients.
Thirteen patients that underwent CPS fixation combined with laminoplasty for CSM with instability were evaluated in this study. We assessed the clinical and radiological results of the surgical procedures. The Japanese Orthopedic Association (JOA) scoring system was used to evaluate the clinical results. The percentages of sli p, difference in sli p angle between maximum flexion and maximum extension of unstable intervertebrae, and perforation rate of CPS were evaluated.
The mean JOA scores before surgery, immediately after surgery, and at final follow-up were 9.1, 13.3, and 12.6, respectively. The mean percentages of sli p before surgery, immediately after surgery, and at final follow-up were 9.1%, 3.2%, and 3.5%, respectively; there were significant improvements immediately after surgery and at final follow-up. The difference in sli p angle between the maximum flexion and maximum extension of the unstable intervertebrae changed from 9.0° before surgery to 1.6° at the final follow-up. The perforation rate of CPS was 10.9%.
The results suggest that CPS fixation combined with laminoplasty is an effective surgical procedure for treating CSM with instability.
Cervical spondylosis; Myelopathy; Instability; Cervical fixation
In this, the second of a two part series, we continue to review the recent literature pertaining to cervical spondylotic myelopathy (CSM). Caused by the compromise of the spinal canal resulting from the superimposition of spondylotic changes upon a congenitally narrowed canal, CSM has a predictable radiographic and clinical presentation. The clinical presentation frequently includes both upper and lower motor neuron signs and symptoms. Careful analysis of the plain film images usually reveals a spinal canal measuring 12 mm or less. Additional imaging modalities confirm the diagnosis.
This paper presents the clinical and imaging characteristics underlying CSM and stresses the importance of including CSM in the differential diagnosis of patients complaining of neck and leg dysfunctions.
cervical spondylotic myelopathy; cervical spine; spondylosis; radiology; chiropractic; manipulation
Traumatic spinal cord injuries represent a significant source of morbidity in humans. Despite decades of research using experimental models of spinal cord injury to identify candidate therapeutics, there has been only limited progress toward translating beneficial findings to human spinal cord injury. Thoracolumbar intervertebral disk herniation is a naturally occurring disease that affects dogs and results in compressive/contusive spinal cord injury. Here we discuss aspects of this disease that are analogous to human spinal cord injury, including injury mechanisms, pathology, and metrics for determining outcomes. We address both the strengths and weaknesses of conducting pre-clinical research in these dogs, and include a review of studies that have utilized these animals to assess efficacy of candidate therapeutics. Finally, we consider a two-species approach to pre-clinical data acquisition, beginning with a reproducible model of spinal cord injury in the rodent as a tool for discovery with validation in pet dogs with intervertebral disk herniation.
animal model; canine; trauma
Five dogs, four small mixed breed and a Doberman Pinscher, presented in our clinic with hemivertebra. Complete physical, radiological and neurological examinations were done and the spinal deformities were characterized in accord with the Nasca classification used in human medicine. Two dogs had multiple hemivertebrae (round, oval or wedge-shaped: Type 3) in the thoracic region; one dog had an individual surplus half vertebral body (Type 1) plus a wedge-shaped hemivertebra (Type 2b) in the lumbar region; one dog had multiple hemivertebrae which were fused on one side (Type 4a) in the thoracic region; and one dog had a wedge-shaped hemivertebra (Type 2a) in the cervical region.
Dog; Vertebral anomaly; Hemivertebra; Nasca classification
Acute paraplegia is a true emergency. It is often the result of trauma but is rarely reported in association with cervical disk herniation in patients without antecedent injury.
This 75-year-old man presented with acute paraplegia due to severe compression of the spinal cord by herniation of the C4-C5 cervical disk. He underwent emergency diskectomy and anterior fusion. Postoperatively, his neurologic functions improved gradually.
Cervical disk herniation should be considered in the differential diagnosis of nontraumatic acute paraplegia. Pre-existing narrowed canal is an important predisposing factor and excessive neck movements are believed to be triggering factors. Immediate early decompressive surgery is recommended to avoid irreversible progression of neurologic deficit.
Paraplegia, acute, nontraumatic; Cervical vertebrae; Intervertebral disk displacement; Spinal cord compression; Rehabilitation, physical
Pinschers and other dogs with coat color dilution show a characteristic pigmentation phenotype. The fur colors are a lighter shade, e.g. silvery grey (blue) instead of black and a sandy color (Isabella fawn) instead of red or brown. In some dogs the coat color dilution is sometimes accompanied by hair loss and recurrent skin inflammation, the so called color dilution alopecia (CDA) or black hair follicular dysplasia (BHFD). In humans and mice a comparable pigmentation phenotype without any documented hair loss is caused by mutations within the melanophilin gene (MLPH).
We sequenced the canine MLPH gene and performed a mutation analysis of the MLPH exons in 6 Doberman Pinschers and 5 German Pinschers. A total of 48 sequence variations was identified within and between the breeds. Three families of dogs showed co-segregation for at least one polymorphism in an MLPH exon and the dilute phenotype. No single polymorphism was identified in the coding sequences or at splice sites that is likely to be causative for the dilute phenotype of all dogs examined. In 18 German Pinschers a mutation in exon 7 (R199H) was consistently associated with the dilute phenotype. However, as this mutation was present in homozygous state in four dogs of other breeds with wildtype pigmentation, it seems unlikely that this mutation is truly causative for coat color dilution. In Doberman Pinschers as well as in Large Munsterlanders with BHFD, a set of single nucleotide polymorphisms (SNPs) around exon 2 was identified that show a highly significant association to the dilute phenotype.
This study provides evidence that coat color dilution is caused by one or more mutations within or near the MLPH gene in several dog breeds. The data on polymorphisms that are strongly associated with the dilute phenotype will allow the genetic testing of Pinschers to facilitate the breeding of dogs with defined coat colors and to select against Large Munsterlanders carrying BHFD.
Eight patients with midline cervical disc protrusion at the C3-4 intervertebral level showed unusual clinical signs: numbness in the finger tips and palms, clumsiness of the hands, and a tightening sensation at the midthoracic level. The proprioceptive and cutaneous sensory afferents essential for motor control of the upper limbs were preferentially involved, tactile discrimination of passively given stimuli being spared. Somatosensory evoked potentials subsequent to median nerve stimulation showed conduction failure through the fasciculus cuneatus, as evidenced by absent or delayed and attenuated medullary and scalp potentials. The potential originating in the lower cervical cord (N13a) had a low amplitude, indicative of the caudal extension of the lesion. On the basis of the functional anatomy of the intraspinal pathways, especially of the dorsal columns, it is concluded that involvement of the central cord at the C3-4 intervertebral level and its caudal extension is responsible for the syndrome.
The purpose of this study is to describe and discuss the treatment of a cervical disk herniation using a sequential multimodal conservative management approach.
A 40-year-old man had complaints of headache and severe sharp neck pain radiating to his left shoulder down to his arm, forearm, and hand. Results of electromyography/nerve conduction studies were abnormal. Magnetic resonance imaging revealed a large disk protrusion at C5-C6 with indentation of the thecal sac and a spur at the posterior margin. Moderate left neural foraminal narrowing was present at C5-C6 with narrowed intervertebral disk space at C5-C6 and C6-C7.
Intervention and Outcome
High-velocity, low-amplitude chiropractic manipulation; electrotherapy; ice; and exercise were used for treatment. The Neck Disability Index was used as a primary and electromyography/nerve conduction studies as a secondary outcome measurement. Based on the Neck Disability Index, there was an overall 89.65% symptoms improvement from the baseline.
This case study demonstrated possible beneficial effects of the multimodal treatment approach in a patient with cervical radiculopathy.
Chiropractic; Cervical vertebrae; Cryotherapy; Intervertebral disk displacement; Manipulation, spinal; Radiculopathy; Rehabilitation
To determine the effect of severity of cervical spondylotic myelopathy (CSM) on gait parameters according to the number of involved spinal cord segments.
Overview of Literature
Although there are a large number of studies on CSM, almost all studies have focused on hand function and only a few studies have examined the gait function in patients with CSM.
Twenty-three patients with CSM underwent magnetic resonance imaging and gait analysis. The subjects were divided into 2 groups; group I consisted of 9 patients with a single-level stenotic lesion and group II comprised 14 patients with multi-level stenotic lesions. Gait parameters were compared between the 2 groups and the normal control group.
There was no significant difference in the Japanese Orthopaedic Association score between the 2 groups. Cadence, walking speed, stride length, and step length were decreased in group II compared to group I and normal control group. Peak ankle plantar flexion moments during the stance phase and peak knee flexion angle during the swing phase were decreased in group II. Peak ankle, knee, and hi p power generation during the stance phase were decreased in group II; in addition, the peak ankle power generation was decreased in group II than in the normal control group.
Patients with multi-level stenotic lesions had decreased gait ability compared to that in patients with a single-level stenotic lesion. The number of involved spinal cord segments can be one cause of gait deterioration in patients with CSM. Performing a gait analysis is useful for accurate evaluation of the patient.
Cervical spondylotic myelopathy; Gait analysis; Multi-level
Load and activity changes of the spine typically cause symptoms of nerve root compression in subjects with spinal stenosis. Protrusion of the intervertebral disc has been regarded as the main cause of the compression. The objective was to determine the changes in the size of the lumbar spinal canal and especially those caused by the ligamentum flavum and the disc during loaded MRI. For this purpose an interventional clinical study on consecutive patients was made. The lumbar spines in 24 supine patients were examined with MRI: first without any external load and then with an axial load corresponding to half the body weight. The effect of the load was determined through the cross-sectional areas of the spinal canal and the ligamentum flavum, the thickness of ligamentum flavum, the posterior bulge of the disc and the intervertebral angle. External load decreased the size of the spinal canal. Bulging of the ligamentum flavum contributed to between 50 and 85% of the spinal canal narrowing. It was concluded that the ligamentum flavum, not the disc had a dominating role for the load induced narrowing of the lumbar spinal canal, a finding that can improve the understanding of the patho-physiology in spinal stenosis.
Ligamentum flavum; Intervertebral disc; Spinal stenosis; Cauda equina; Loaded MRI
An association between the occurrence of calcified discs, visible on radiographic examination (CDVR), and disc extrusions has been suggested in published literature over the past 10-20 years, mainly from Nordic countries. It has also been postulated that dogs without CDVR would not develop disc extrusions. Furthermore, inheritance of CDVR has been calculated and it has been postulated that, by selecting dogs for breeding with few, or no CDVR, the prevalence of disc extrusions in the Dachshund population may be reduced.
The prevalence of radiographic detectable intervertebral disc calcifications was calculated from one hundred surgeries for disc extrusion, performed in 95 Dachshunds, in order to determine if the disc causing clinically significant IVDD, had radiographic signs of calcification at the time of confirmed disc extrusion. Inclusion criteria, for each dog, included a complete physical, orthopedic and neurologic examination, radiographs of the entire vertebral column, a myelogram or magnetic resonance imaging examination indicating extradural spinal cord compression, and finally a surgical procedure confirming the diagnosis of a disc extrusion. In addition to descriptive statistics, age correlation with number of calcifications visible at radiographic examination and with CDVR at the surgery site was examined.
We found that disc extrusions occur as frequently in discs that are found to have radiographic evidence of calcification as those discs that do not have signs of radiographic calcification, and that IVDD (intervertebral disc disease) requiring surgery does occur in the absence of any calcified discs on radiographic examination. We found that calcified discs were more frequent in our Dachshund population compared to previous studies suggesting that disc calcification might be a serious risk factor for developing disc extrusion. Further studies are needed to show, conclusively, if selection of breeding dogs based on CDVR in the Dachshund will reduce the incidence of IVDD. The presence of the calcifications of intervertebral disc should be evaluated with caution, as only part of the calcifications will be detected and the real extent of the disc degeneration may be underestimated.
This is a prospective analysis of 129 patients operated for cervical spondylotic myelopathy (CSM). Paucity of prospective data on surgical management of CSM, especially multilevel CSM (MCM), makes surgical decision making difficult. The objectives of the study were (1) to identify radiological patterns of cord compression (POC), and (2) to propose a surgical protocol based on POC and determine its efficacy. Average follow-up period was 2.8 years. Following POCs were identified: POC I: one or two levels of anterior cord compression. POC II: one or two levels of anterior and posterior compression. POC III: three levels of anterior compression. POC III variant: similar to POC III, associated with significant medical morbidity. POC IV: three or more levels of anterior compression in a developmentally narrow canal or with multiple posterior compressions. POC IV variant: similar to POC IV with one or two levels, being more significant than the others. POC V: three or more levels of compression in a kyphotic spine. Anterior decompression and reconstruction was chosen for POC I, II and III. Posterior decompression was chosen in POC III variant because they had more incidences of preoperative morbidity, in spite of being radiologically similar to POC III. Posterior surgery was also performed for POC IV and IV variant. For POC IV variant a targeted anterior decompression was considered after posterior decompression. The difference in the mJOA score before and after surgery for patients in each POC group was statistically significant. Anterior surgery in MCM had better result (mJOA = 15.9) versus posterior surgery (mJOA = 14.96), the difference being statistically significant. No major graft-related complications occurred in multilevel groups. The better surgical outcome of anterior surgery in MCM may make a significant difference in surgical outcome in younger and fitter patients like those of POC III whose expectations out of surgery are more. Judicious choice of anterior or posterior approach should be made after individualizing each case.
Cervical spondylotic myelopathy; Anterior surgical approach; Laminectomy
The ability to compare various results that measure clinical deficits and outcome is a necessity for successful worldwide discussion about cervical spondylogenic myelopathy (CSM) and its treatment. There is hardly any information in literature how to value and compare outcome assessed by different scores. In a retrospective study we objectively evaluated the Nurick-score, Japanese-orthopaedic-association-score (JOA-Score), Cooper-myelopathy-scale (CMS), Prolo-score and European-myelopathy-score (EMS) using the data of 43 patients, all of whom showed clinical and morphological signs of CSM and underwent operative decompression. The scores were assessed pre- and postoperatively. The correlation between the score-results, anamnesis, clinical and diagnostic data was investigated. All the scores show a statistically significant correlation and measure postoperative improvement. With exception of the Prolo-score all scores reflect clinical deficits of CSM. The Prolo-score rates the severity of CSM on the state of the economic situation above clinical symptoms. The main differences of the scores are shown in the number of patients showing postoperative improvement, varying between 33% (Nurick-score) and 81% (JOA-score). The recovery-rates, as a measure of the cumulative improvement of all the symptoms, show less variation (23–37%). The differences of the recovery-rate were only statistically significant between JOA-score, Nurick-score and EMS (P < 0.05), whereas all the other scores showed no significant differences. To assess the postoperative successes, the evaluation of the recovery-rate is essential. There is no significant difference in the recovery-rate amongst the majority of the scores, which allows a good comparison of the results from different studies. Nevertheless, it is always important to differentiate the therapy results of CSM published worldwide.
Cervical myelopathy; Scores; Outcome; Recovery rate; Preoperative validation; Postoperative validation
The prevalence of gross and/or histological cardiac lesions was found to be much greater in Doberman pinscher dogs (16/26 or 62%) than in non-Doberman dogs (124/417 or 30%). At least some of the affected Dobermans were unrelated. Middle aged (mean age 4.7 yr) Dobermans of both sexes (11 M:5F) were affected. Four of the Dobermans with heart lesions had congestive cardiomyopathy; three of these four had congestive heart failure and the other one died suddenly. Prominent gross lesions were ventricular dilation and atrioventricular valvular endocardiosis. Histological lesions noted were prominent myocardial fibrosis, myofiber degeneration with fatty replacement, myofiber vacuolation and arterial intimal cushion formation. A spectrum of myocardial disease exists in Dobermans and clinically overt congestive cardiomyopathy represents one end of this spectrum.
For some scoliotic patients the spinal instrumentation is inevitable. Among these patients, those with stiff curvature will need thoracoscopic disk resection. The removal of the intervertebral disk with only thoracoscopic images is a tedious and challenging task for the surgeon. With computer aided surgery and 3D visualisation of the interverterbral disk during surgery, surgeons will have access to additional information such as the remaining disk tissue or the distance of surgical tools from critical anatomical structures like the aorta or spinal canal. We hypothesized that automatically extracting 3D information of the intervertebral disk from MR images would aid the surgeons to evaluate the remaining disk and would add a security factor to the patient during thoracoscopic disk resection.
This paper presents a quantitative evaluation of an automatic segmentation method for 3D reconstruction of intervertebral scoliotic disks from MR images. The automatic segmentation method is based on the watershed technique and morphological operators. The 3D Dice Similarity Coefficient (DSC) is the main statistical metric used to validate the automatically detected preoperative disk volumes. The automatic detections of intervertebral disks of real clinical MR images are compared to manual segmentation done by clinicians.
Results show that depending on the type of MR acquisition sequence, the 3D DSC can be as high as 0.79 (±0.04). These 3D results are also supported by a 2D quantitative evaluation as well as by robustness and variability evaluations. The mean discrepancy (in 2D) between the manual and automatic segmentations for regions around the spinal canal is of 1.8 (±0.8) mm. The robustness study shows that among the five factors evaluated, only the type of MRI acquisition sequence can affect the segmentation results. Finally, the variability of the automatic segmentation method is lower than the variability associated with manual segmentation performed by different physicians.
This comprehensive evaluation of the automatic segmentation and 3D reconstruction of intervertebral disks shows that the proposed technique used with specific MRI acquisition protocol can detect intervertebral disk of scoliotic patient. The newly developed technique is promising for clinical context and can eventually help surgeons during thoracoscopic intervertebral disk resection.
It is rare that the medial loop in the V2 segment of the vertebral artery (VA) causes compression of the proximal cervical root of the spinal cord without leading to bony erosion and an enlarged foramen. We evaluated the clinical significance and incidence of the medial loop in the V2 segment of the VA.
We reviewed the records from 1000 consecutive patients who had undergone magnetic resonance imaging evaluation of the cervical spine between January 2005 and January 2008. The inclusion criteria were that over a third of the axial aspect of the VA located in the intervertebral foramen was inside the line between the most ventral points of the bilateral lateral mass, and that the ipsilateral proximal root deviated dorsally because of the medial loop of the VA. We excluded cases of bone erosion, a widened foramen at the medial loop of the VA, any bony abnormalities, tumors displacing VA, or vertebral fractures. The medical records were reviewed retrospectively to search for factors of clinical significance.
In six patients (0.6%), the VA formed a medial loop that caused compression of the proximal cervical root. One of these patients had the cervical radiculopathy that developed after minor trauma but the others did not present with cervical radiculopathy related to the medial loop of the VA.
The medial loop of the VA might have a direct effect on cervical radiculopathy. Therefore, this feature should be of critical consideration in preoperative planning and during surgery.
Vertebral artery; Medial loop; Spine
The anterior cervical discectomy (ACD) is often used to treat spinal cord and nerve root compressions and the frequent use of interbody fusion (ACDF) has popularized it as a common practice associated or not with cages or plates for maintaining the intervertebral disc height.
The aim of this study is to clarify the effectiveness of ACD compared with ACDF, with or without the use of anterior cervical spacer (Cage) or instrumentation with plate fixation (ACDFI).
randomized controlled trials or quasi-randomized trials were selected for analysis in one segmental level. The comparison criteria were the rates of success and failure with surgery (Odom’s’ criteria), fusion rates and kyphosis rates. Electronic search was made in the MEDLINE database (Pubmed), in the Central Registry of randomized trials of Cochrane database and EMBASE.
Seven studies were selected for analysis.
Implications for practice: There is moderate evidence that clinical results of ACD and ACDF are not significant different. There is moderate evidence that addition of intervertebral cage enhance clinical results.There is moderate evidence that anterior cervical plate does not change the clinical results of ACD.
There is moderate evidence that ACD produce more segmental kyphosis than ACDF and ACDFI, with use of cage or plate.There is moderate evidence that ACD produce lower rate of fusion than ACDF and than the cages. There is limited evidence of the lower capacity of PMMA to produce fusion. There is limited evidence that fused patients have better outcome than non fused patients.
Diskectomy; cervical spine; surgery; meta analysis.