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PubMed2000

Therapeutic indications in upper cervical spine instability. Considerations on 58 cases.

BACKGROUND: The particular biomechanics of the upper cervical spine require, when trauma occurs, careful evaluation of the stability of the lesions, in order to guarantee the best possible therapeutic and prognostic approach. To date, there has been no uniformity of opinion in merit, especially with reference to treatment of odontoid fractures. It is necessary for this reason as much as for the opportune standardisation of the patients' classification parameters to establish what is meant by stability and which lesions are to be held as being unstable in the upper cervical spine. METHODS: All the cases of upper cervical spine instability treated in our Unit from '94 to date have been reviewed. Four fractures to the first cervical vertebra, 29 to the odontoid process, 9 isolated fractures in the C2 body, 12 hangman fractures, 7 fractures of the articular processes, 2 to the occipital condyles and 4 C1-C2 dislocations without fractures were localised. Using precise prognostic indexes as our classification criteria, 56 of the 58 patients observed were addressed towards either conservative treatment or directly towards surgical treatment. In particular, 29 patients were conservatively treated with a collar or Halo-Vest. Twenty-seven surgical operations were carried out: 14 screw fixations, 6 anterior fixations using plates and screws, 4 rear ones using metal wire or wire with bone graft, 3 odontectomy operations associated with posterior fixation. RESULTS: In the follow-up, using a range of between three months to six years, good fusion with spine stabilisation was achieved in all the patients treated. In particular, surgery was carried out as the first therapeutic indication in 25 cases, obtaining excellent results. Surgery was necessary in only 2 cases after the failure of external stabilisation. CONCLUSIONS: The judgement passed on instability in traumatic lesions in the upper cervical spine represents the decisive factor in the choice of the therapeutic option. Instead of always opting for conservative treatment, in the case of C1-C2 fractures-luxations, and going ahead with surgery only when there is instability or non-fusion of the segments resulting after successive monitoring, we believe that the definition and standardisation of the prognostic factors is opportune, in order to provide patients with a specific solution, in such a way as to reduce the failure percentage of the first treatment and optimise the healing time.

Adolescent↗
PubMed2000

Nonoperative management of dens fracture nonunion in elderly patients without myelopathy.

STUDY DESIGN: A retrospective review of elderly patients treated without surgery for chronic mobile nonunions of the odontoid process. Patients were observed on an annual basis with clinical examinations and flexion/extensions plain film radiographs. OBJECTIVES: To evaluate the clinical and radiographic results of elderly patients without myelopathy treated without surgery for dens fracture nonunion. SUMMARY OF BACKGROUND DATA: Because of the risk of progressive myelopathy or sudden neurologic injury, many surgeons recommend operative stabilization for patients with mobile dens nonunions who are able to withstand an operation. There is, however, a lack of information about the radiographic and neurologic progression of dens nonunions. Although a less aggressive surgical approach has been recommended by some authors for elderly or medically compromised patients with acute fractures, long-term follow-up evaluation of patients with resulting nonunions has not been reported. METHODS: A series of elderly patients with chronic, unstable, dens nonunions without myelopathy were treated with a nonoperative treatment protocol. Patients were informed of the nature of their lesion, including the risk of acute or chronic spinal cord injury and the options for operative treatment. Patients were evaluated yearly for clinical and radiographic progression. No intervention to slow progression of atlantoaxial instability was undertaken. RESULTS: None of the patients developed myelopathic symptoms during the follow-up period, and no patient experienced more than a 1 mm radiographic increase in atlantoaxial excursion. None of the reported patients had less than 14 mm available for the spinal cord in either flexion or extension at the start of clinical monitoring. CONCLUSIONS: Although further follow-up evaluation is needed, the authors believe on the basis of this review that this treatment protocol may be considered for patients who are poor candidates for surgical fusion.

Aged↗
PubMed2005

Subdental synchondrosis and anatomy of the axis in aging: a histomorphometric study on 30 autopsy cases.

During skeletal development the two ossification centers of the odontoid process are separated from the corpus of the axis by a subdental synchondrosis. This synchondrosis is thought to close and disappear spontaneously in adolescence although this has never been studied in detail. The basis of the dens is of clinical relevance as type II dens fractures are located here. To characterize the morphological architecture of the axis with particular attention to the subdental synchondrosis, the complete axis was harvested from thirty age-matched and gender-matched patients of the three different age groups at autopsy. The subdental synchondrosis and the bone structure of the dens, the basis of the dens and the body of C2 were analyzed by radiography, histology and quantitative histomorphometry. At the macroscopic level the persistency of the subdental synchondrosis in the adult cervical spine was detected in 87% (26 of 30) of the specimens. Histomorphometry revealed a residual disc blastema with an average size of 25.8% of the sagittal depth of the basis of the dens at this level. Bony integration of the synchondrosis was poor throughout all ages. Histologically a cartilaginous matrix composition of the subdental synchondrosis persisted throughout all groups. The trabecular microarchitecture demonstrated a significant reduction of bone volume and trabecular number as well as an increased trabecular separation within the basis of the dens as compared to the corpus or the dens of C2. This histomorphometric data regarding a poor integration of the synchondrosis into the trabecular network and the reduced bone mass within the basis of the dens might offer a previously underestimated explanation for the occurrence of type II dens fractures and their association with pseudoarthrosis, respectively.

Adult↗
PubMed2006

Superior odontoid migration in the Klippel-Feil patient.

Klippel-Feil syndrome (KFS) is an uncommon condition noted primarily as congenital fusion of two or more cervical vertebrae. Superior odontoid migration (SOM) has been noted in various skeletal deformities and entails an upward/vertical migration of the odontoid process into the foramen magnum with depression of the cranium. Excessive SOM could potentially threaten neurologic integrity. Risk factors associated with the amount of SOM in the KFS patient are based on conjecture and have not been addressed in the literature. Therefore, this study evaluated the presence and extent of SOM and the various risk factors and clinical manifestations associated therein in patients with KFS. Twenty-seven KFS patients with no prior history of surgical intervention of the cervical spine were included for a prospective radiographic and retrospective clinical review. Radiographically, McGregor's line was utilized to evaluate the degree of SOM. Anterior and posterior atlantodens intervals (AADI/PADI), number of fused segments (C1-T1), presence of occipitalization, classification-type, and lateral and coronal cervical alignments were also evaluated. Clinically, patient demographics and presence of cervical symptoms were assessed. Radiographic and clinical evaluations were conducted by two independent blinded observers. There were 8 males and 19 females with a mean age of 13.5 years at the time of radiographic and clinical assessment. An overall mean SOM of 5.0 mm (range = -1.0 to 19.0 mm) was noted. C2-C3 (74.1%) was the most commonly fused segment. A statistically significant difference was not found between the amount of SOM to age, sex-type, classification-type, AADI, PADI, and lateral cervical alignment (P > 0.05). A statistically significant greater amount of SOM was found as the number of fused segments increased (r = 0.589; P = 0.001) and if such levels included occipitalization (r = 0.616; P = 0.001). A statistically significant greater amount of SOM was also found with an increase in coronal cervical alignment (r = 0.413; P = 0.036). Linear regression modeling further supported these findings as the strongest predictive variables contributing to an increase in SOM. A 7.20 crude relative risk (RR) ratio [95% confidence interval (CI) = 1.05-49.18; risk differences (RD) = 0.52] was noted in contributing to a SOM greater than 4.5 mm if four or more segments were fused. Adjusting for coronal cervical alignment greater than 10 degrees , five or more fused segments were found to significantly increase the RR of a SOM greater than 4.5 mm (RR = 4.54; 95% CI = 1.07-19.50; RD = 0.48). The RR of a SOM greater than 4.5 mm was more pronounced in females (RR = 1.68; 95% CI = 0.45-6.25; RD = 0.17) than in males. Eight patients (29.6%) were symptomatic, of which symptoms in two of these patients stemmed from a traumatic event. However, a statistically significant difference was not found between the presence of symptoms to the amount of SOM and other exploratory variables (P > 0.05). A mean SOM of 5.0 mm was found in our series of KFS patients. In such patients, increases in the number of congenitally fused segments and in the degree of coronal cervical alignment were strongly associated risk factors contributing to an increase in SOM. Patients with four or greater congenitally fused segments had an approximately sevenfold increase in the RR in developing SOM greater than 4.5 mm. A higher RR of SOM more than 4.5 mm may be associated with sex-type. However, 4.5 mm or greater SOM is not synonymous with symptoms in this series. Furthermore, the presence of symptoms was not statistically correlated with the amount of SOM. The treating physician should be cognizant of such potential risk factors, which could also help to indicate the need for further advanced imaging studies in such patients. This study suggests that as motion segments diminish and coronal cervical alignment is altered, the odontoid orientation is located more superiorly, which may increase the risk of neurologic sequelae.

Adolescent↗
PubMed1995

Painful torticollis with tongue atrophy--a different neck-tongue syndrome.

Two children were referred with neck pain, torticollis, dysarthria, and atrophy of the tongue. The erythrocyte sedimentation rate was markedly elevated in both cases. Radiologic appearances were similar. In both cases the cervical spine was stable. Computerised tomography showed soft-tissue swelling surrounding the odontoid process and distorting the theca. Magnetic resonance imaging showed gadolinium enhancement of the soft tissue overlying the clivus and around the odontoid, impinging on the medulla and high cervical cord. Biopsy in the second case was not diagnostic. Steroids led to a dramatic and sustained improvement in symptoms and a marked decrease in soft tissue mass. The history, elevated inflammatory indices, radiologic appearance and response to steroids, are consistent with an inflammatory process.

Atrophy↗
PubMed2004

Multidetector computed tomography of cervical spine fractures in ankylosing spondylitis.

PURPOSE: To analyze multidetector computed tomography (MDCT) cervical spine findings in trauma patients with advanced ankylosing spondylitis (AS). MATERIAL AND METHODS: Using PACS, 2282 cervical spine MDCT examinations requested by emergency room physicians were found during a period of 3 years. Of these patients, 18 (16 M, aged 41-87, mean 57 years) had advanced AS. Primary imaging included radiography in 12 and MRI in 11 patients. RESULTS: MDCT detected one facet joint subluxation and 31 fractures in 17 patients: 14 transverse fractures, 8 spinous process fractures, 2 Jefferson's fractures, 1 type I and 2 type II odontoid process fractures, and 1 each: atlanto-occipital joint fracture and C2 laminar fracture plus isolated transverse process and facet joint fractures. Radiographs detected 48% and MRI 60% of the fractures. MRI detected all transverse and odontoid fractures, demonstrating spinal cord abnormalities in 72%. CONCLUSION: MDCT is superior to plain radiographs or MRI, showing significantly more injuries and yielding more information on fracture morphology. MRI is valuable, however, in evaluating the spinal cord and soft-tissue injuries. Fractures in advanced AS often show an abnormal orientation and are frequently associated with spinal cord injuries. In these patients, for any suspected cervical spine injuries, MDCT is therefore the imaging modality of choice.

Adult↗
PubMed2005

Magnetic resonance imaging study of the craniocervical junction.

PURPOSE: To confirm the accuracy of the standard parameters of Chamberlain's line, McGregor's line, McRae's line, and Ranawat's line in the diagnosis of basilar impression in a normal Asian population using magnetic resonance imaging (MRI) scans of the craniocervical junction, and to evaluate the use of MRI in the initial diagnosis of basilar impression. METHODS: We retrospectively reviewed MRI scans of the craniocervical junction in 114 Thai patients (61 men and 53 women) aged 20 to 89 years to assess the lines of Chamberlain, McGregor, McRae, and Ranawat. Patients with injury, tumour, or metastasis in the craniocervial junction; congenital anomalies; or clinical symptoms and signs of basilar impression were excluded. RESULTS: 39 of the 114 patients had the odontoid tip extended above Chamberlain's line by 1 mm to 9 mm (mean, 2.89 mm). Only 7 men and 5 women had the tip of the odontoid process extended beyond the normal range of 5 mm. The mean distance of the odontoid tip extended past McGregor's line in male and female subjects was 0.33 mm (standard deviation [SD], 1.2 mm) and 0.17 mm (SD, 0.7 mm), respectively, markedly less than those reported previously, although one male patient's odontoid tip extended 8 mm above the McGregor's line. Regarding McRae's line, no patient had the odontoid tip extended above the foremen magnum. The mean Ranawat's line in male and female subjects was 15.75 mm (range, 12-19; SD, 1.71 mm) and 14.09 mm (range, 11-17; SD, 1.38 mm), respectively. CONCLUSION: After using MRI to confirm the standard parameters of basilar impression as previously formulated from lateral skull radiographs, we recommend using McRae's line and Ranawat's line in the initial screening for basilar impression for the Asian population. Chamberlain's line and McGregor's line are viable alternatives, but clinicians must be aware of the potential for false positives.

Adult↗
PubMed2001

Biomechanical study of C2 (Axis) fracture: effect of restraint.

INTRODUCTION: In human, the cervical spine region is very susceptible to impact injury. The complex structures of C1 and C2 serve to transmit the weight of the cranium to the greatly similar structural cervical spine from C3 caudally. Application of sudden disruption forces will detach the junction of the cervico-cranium with the pars interarticularis of the neural arch of C2 from the lower cervical spine by fracturing, as in a "hangman's fracture". Severe falls or blows to the head from heavy objects will cause the fracture of the odontoid process of C2. Many biomechanical studies were conducted based on full restraint of the inferior aspects of isolated C2 to produce odontoid fracture. In this study, two different restraining conditions of C2 were adopted experimentally to determine the absolute fracture load and the corresponding fracture patterns that are common to C2. MATERIALS AND METHODS: Nine C2 vertebrae obtained from cadaver spines, ranging from 51 to 80 years, were used. Two specified restraint conditions were employed: (1) fully constrain the posterior element postero-anteriorly up to one-quarter of the inferior facet; and (2) fixing of C2 by a specially-designed rig whereby the body of C2 embedded in the pivoted cup and its inferior facets positioned on top of two lateral plates. Antero-posterior shear force was applied on the anterior articulating facet of the dens until failure. RESULTS: These specified restraint conditions had resulted in specific fracture of C2. Antero-posterior shear force ranges from 840 to 1220 N was required to cause fracture across the pars interarticularis under restraint condition 1. Failure load of between 900 and 1500 N was found to cause odontoid fracture under restraint condition 2. These values are in agreement with published data. CONCLUSIONS: The biomechanical response of C2 was specific to the mode of restraint conditions of C2. In reality, depending on the force vector applied to the head, precise posture at the time of trauma, spinal geometry, and physical properties, different types of C2 fracture patterns may happen. These findings are of potentials for the biomechanical correlation and validation study of C2 vertebra using analytical approaches, and in the surgical anterior screw fixation of odontoid fracture.

Aged↗
PubMed1991

Flexion-extension MRI of the upper rheumatoid cervical spine.

Seven rheumatoid arthritis patients with involvement of the upper cervical spine were evaluated with a dynamic MRI study. Lateral T1 weighted images of the upper C-spine were obtained in the flexion, extension, and neutral positions. The indications for performing the dynamic MRI were radiographic instability of the upper C-spine, myelopathy, superior migration of the odontoid process, obliteration of bony landmarks on plain radiographs, and to determine the contribution of pannus on cord configuration. The dynamic MRI clearly delineated the relationship between the odontoid, foramen magnum, and cervical spinal cord as the neck was moved through a range of motion. This aided in the selection of operative candidates in four cases, and was instrumental in determining fusion levels. In three cases with suspected myelopathy secondary to cord impingement, MRI showed no significant cord compression, and aided in the decision to treat the patients conservatively. Lateral flexion-extension MRI is the diagnostic study of choice in dynamically evaluating the upper rheumatoid C-spine.

Adult↗
PubMed1998

Functional turbo spin echo magnetic resonance imaging versus tomography for evaluating cervical spine involvement in rheumatoid arthritis.

STUDY DESIGN: Comparison of findings in plain radiography and conventional tomography with findings in plain radiography and magnetic resonance imaging of the upper cervical spine in consecutive patients with rheumatoid arthritis and with known or suspected abnormalities of the cervical spine. OBJECTIVES: To determine whether plain radiography and magnetic resonance imaging provide enough information to dispense with tomography in investigations of cervical spine involvement in rheumatoid arthritis. SUMMARY OF BACKGROUND DATA: With the recent advances in magnetic resonance imaging technology and the proliferation of magnetic resonance imaging techniques for specific clinical conditions. METHODS: Twenty-eight patients with rheumatoid arthritis and with known or suspected abnormalities of the cervical spine underwent a clinical neurologic examination; plain radiography, including full flexion lateral radiography; anteroposterior and lateral tomography at C1-C2; and magnetic resonance imaging at the same level in neutral position and in flexion. Two radiologists evaluated one image set consisting of plain radiography and conventional tomographic images and another image set consisting of plain radiography and magnetic resonance images, for each patient. RESULTS: Compared with conventional tomography and plain radiography, magnetic resonance imaging and plain radiography showed cystic lesions and erosions of the odontoid process and vertical atlantoaxial subluxation more often, showed anterior subluxation as often, and showed lateral atlantoaxial subluxation less often. CONCLUSION: Magnetic resonance imaging produces sufficiently distinct images of destruction of the odontoid and subluxations for it to replace conventional tomography in investigations of upper cervical spine involvement in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1984

Odontoid fractures, systemic disease and conservative care.

Patients admitted to the Prince Henry Hospital Spinal Unit between January 1982 and January 1983 with a diagnosis of fracture of the odontoid process of the axis were reviewed. There were nine patients representing 20% of all new cervical fractures. The mean age was 64.5 +/- 19.3 years. Alcoholism, brain damage following head injury, osteo-arthritis, cervical spondylosis, rheumatoid arthritis and osteoporosis may be complicating factors in the management of odontoid fractures. A fracture of the odontoid in an elderly patient with a history of minimal trauma suggests osteoporosis. Early mobilization in a custom-moulded orthosis with frequent radiological monitoring prevents the complications of prolonged bed rest.

Aged↗
PubMed2007

Upper cervical myelopathy due to arachnoiditis and spinal cord tethering from adjacent C-2 osteomyelitis. Case report and review of the literature.

Myelopathy caused by a spinal cord infection is typically related to an adjacent compressive lesion such as an epidural abscess. The authors report a case of progressive high cervical myelopathy from spinal cord tethering caused by arachnoiditis related to an adjacent C-2 osteomyelitis. This 70-year-old woman initially presented with a methicillin-sensitive Staphylococcus aureus osteomyelitis involving the C-2 odontoid process. She was treated with appropriate antibiotic therapy but, over the course of 4 weeks, she developed progressive quadriparesis. A magnetic resonance image revealed near-complete resolution of the C-2 osteomyelitis, but new ventral tethering of the cord was observed at the level of the odontoid tip. She subsequently underwent open surgical decompression and cord detethering. Postoperatively she experienced improvement in her symptoms and deficits, which continued to improve 1 year after her surgery. To the authors' knowledge, this is the first reported case of progressive upper cervical myelopathy due to arachnoiditis and cord tethering from an adjacent methicillin-sensitive S. aureus C-2 osteomyelitis.

Aged↗
PubMed2000

Correction of odontoid dysplasia following bone-marrow transplantation and engraftment (in Hurler syndrome MPS 1H).

BACKGROUND: Odontoid dysplasia is recognized as a major component of the constellation of dysostosis multiplex lesions associated with Hurler's syndrome (MPS 1H). Because of this abnormality, there is an increased risk of atlantoaxial subluxation with potential cervical spinal cord injury. A significant alteration of the natural history of the disease with respect to the visceral, cardiac, and skeletal systems has resulted in an increased life span for MPS 1H patients associated with engraftment from normal donors. OBJECTIVE: The purpose of this study was to evaluate the longitudinal changes of odontoid dysplasia in MPS 1H following engraftment from bone-marrow transplantation (BMT). MATERIALS AND METHODS: A retrospective review of sequential plain film or cervical spine MR was performed in patients with MPS 1H. Odontoid morphology was graded as aplasia, severe dysplasia, moderate dysplasia, mild dysplasia, or normal. Odontoid morphology was plotted against the time interval. Fully engrafted, nontransplanted, and partially engrafted patients had careful imaging evaluation of the odontoid process. RESULTS: Ten patients were studied with a mean interval follow-up of 8.7 years post-BMT. Seven patients were totally engrafted. Two patients were nontransplanted, and one patient had only partial engraftment (20% enzyme activity). All totally engrafted patients had a progressive improvement in the grade of odontoid dysplasia following BMT. Patients with partial engraftment or without transplantation demonstrated static or increasing odontoid dysplasia. MR imaging showed abnormal dural soft-tissue masses at the level of C2 in all patients. Reduction in the grade of odontoid dysplasia was not associated with significant change in the appearance of the upper cervical soft-tissue masses. CONCLUSION: For the first time, this report documents that patients with MPS 1H show a decrease in the degree of odontoid dysplasia on imaging after successful engraftment following BMT.

Bone Diseases, Developmental↗
PubMed1998

Compression of the upper cervical spinal cord causing symptoms of brainstem compromise. A case report.

STUDY DESIGN: A case is reported in which a flexion-induced compression of the upper cervical spinal cord caused symptoms of brainstem compromise in the absence of radiographic evidence of osseous instability. OBJECTIVES: A 41-year-old woman developed postoperative cervical instability with flexion-induced neurologic symptoms referable to the brainstem. The instability was caused by direct compression at the third cervical vertebral body, which in turn was caused by differential movements between the neuraxis and skeletal elements in the upper cervical spine. SUMMARY OF BACKGROUND DATA: Pathologic processes at the craniocervical junction may cause brainstem compromise with neurologic symptoms. The mechanism of brainstem involvement is usually either vertebrobasilar insufficiency or direct mechanical compression. In cases where the brainstem is compressed by skeletal elements, the compressing osseous structures usually are the walls of the foramen magnum or the odontoid process, or, less frequently, the atlas or axis vertebrae. Symptoms of brainstem dysfunction caused by dynamic compression at the level of the third cervical vertebra in the absence of hindbrain herniation are unusual and, to the best of the authors' knowledge, have not been described previously. METHODS: The patient underwent initial examination, evaluation, and periodic follow-up examination with magnetic resonance imaging from the time of her first visit until 26 months after the surgical treatment. The patient experienced postsurgical instability with dynamic compression by the C3 vertebral body, which caused brainstem compromise. Surgical treatment consisted of decompressive C3 corpectomy and fusion of C2 to C6, supplemented by anterior fixation. RESULTS: After undergoing surgical decompression of C3, reconstruction, and anterior internal fixation of C2 to C6, the patient had dramatic neurologic improvement. Diplopia, paresthesia, and nystagmus disappeared immediately after surgery. Swallowing difficulties, hoarseness, and vertigo improved gradually. At follow-up examination 26 months after surgery, the patient was asymptomatic. Magnetic resonance imaging showed good position of the construct, with no evidence of compression of the spinal cord or brainstem. CONCLUSIONS: Instability of the cervical spine may result in symptoms of brainstem dysfunction, even in the absence of hindbrain herniation. This instability is explained by the differential movement between the bony structures and neuraxis in the upper cervical region. Diagnosis and adequate management of this instability alleviates the neurologic symptoms and prevents possible hazardous complications.

Adult↗
PubMed2003

Teaching evidence-based medicine to surgical subspecialty residents.

BACKGROUND: Curricula for the teaching of evidence-based medicine to residents have been the subject of reports, analyses, and commentary. Specific programs for teaching evidence-based medicine principles to surgical subspecialty residents have not been identified by the authors. The objective of this article is to report our experience in establishing a teaching program in the principles of evidence-based medicine to surgical subspecialty residents. STUDY DESIGN: We established a teaching program in the principles of evidence-based medicine for neurosurgical residents in a busy neurosurgical training program. Two hours were set aside every other week, replacing traditional professors' rounds with sessions led jointly by a neurosurgeon and an epidemiologist, but based on case presentations from patients currently being treated. From these presentations, searchable clinical questions were developed, and the literature was searched, critically analyzed, and summarized. Results of several cycles on this process are reported. RESULTS: The group developed a repository of Internet-based resources for evidence-based education and practice. Using these resources, the group analyzed six topics in the first 2 years of the program. These included the "best" way to clinically grade patients after subarachnoid hemmorhage, considerations in the biopsy and treatment of enhancing intracerebral mass lesions in patients with acquired immunodeficiency syndrome, the use of prophylactic anticonvulsants in patients with primary brain tumors, the identification of cervical spine injuries in the emergency department, the grading of the fractures of the odontoid process, and the value of removing retained bullets from the spinal canal. The outcomes ranged from finding insufficient evidence to reach a conclusion, through the identification of well-conducted and well-reported critical syntheses of the topic already available in literature, to the development of the detailed algorithm for cervical spine clearance that was accepted by the institution's emergency department. CONCLUSIONS: By dedicating some specific time and using resources readily available in most academic health centers, it is possible to incorporate the teaching of the principles of evidence-based practice into the ongoing education of residents on a busy surgical subspecialty service.

Curriculum↗
PubMed1997

Left-right asymmetries and other common anatomical variants of the first cervical vertebra.

SUMMARY. Left-right asymmetries were systematically and independently observed twice in 82 macerated atlases by three investigators using a check-list and the instructions of an examination protocol. A grid behind the vertebra served as a visual aid and was inserted in an inclinometer box used for measuring zygapophyseal joint facet inclination. Only those asymmetries observed once by each of the investigators were listed. The posterior arch showed the highest number of asymmetries and many unequal grooves for the vertebral artery were observed. The lateral compartment frequently revealed asymmetries of transverse processes and transverse foramina. These results are indicative of variants of the bony canal for passage of the vertebral artery and asymmetric lever arms for muscles, inserted at C1. A third zone could be defined at the level of the joint facets. Tropism of the superior joint facets was caused by differences in shape, size, surface area, curvature, inclination relative to the sagittal plane, implantation on the lateral mass, unilateral or asymmetric subdivision. Left-right differences of inferior joint facets were often related to degenerative enlargement. Osteophytes also caused asymmetry of the facet for the odontoid process. An important number of combined asymmetries reveals questions about their functional consequences. Copyright 1997 Harcourt Publishers Ltd.

Journal Article↗
PubMed1989

Anterior screw fixation of posteriorly displaced type II odontoid fractures.

Posteriorly displaced Type II odontoid fractures (Type II-P) are difficult to stabilize in an anatomic position with accepted methods of posterior atlantoaxial arthrodesis. Nine patients with Type II-P odontoid fractures with 4 to 15 mm displacement were treated with anterior odontoid screw stabilization. Seven of these patients had associated fractures or defects of the posterior arch of the first cervical vertebra (C1). Atlantoaxial posterior arthrodesis in these patients would not have been possible initially because of the lack of structural integrity of the posterior arch of C1. Two patients, later in the study, had no injury to the ring of C1. The odontoid fractures were stabilized with two 4.0-mm cancellous screws inserted through an anterior approach to the neck under fluoroscopic control with the skin incision at the C5 level. Preoperative reduction of the displaced odontoid process and immediate operative stability of the atlantoaxial complex were obtained in each case. No neurological complications related to the procedure occurred. Two patients died of causes unrelated to their cervical fracture surgery. The 7 patients who survived were followed for a minimum of 6 months. Fracture union and cervical stability were demonstrated in each of the surviving patients, without evidence of screw loosening or loss of fixation. Normal range of motion of the neck was documented at follow-up in all surviving patients. Although this series represents a limited experience with this treatment technique, anterior odontoid screw fixation has significant advantages over accepted methods of cervical stabilization for Type II-P odontoid fractures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Atlantoaxial arthrodesis to treat odontoid fractures.

The authors reviewed 132 cases of cervical spine fracture over a 10-year period and found 24 cases of fracture of the odontoid process. Using the classification of Anderson and D'Alonzo, they found 20 patients with type II fractures and 4 with type III injuries. Sixteen patients with type II fractures and 1 with type III underwent posterior atlantoaxial fusion by the Gallie method or a modification of it. Immobilization following arthrodesis was by soft cervical ruffs and a four-poster collar. Solid fusion was obtained within 3 to 6 months in 15 of the 16 type II fractures; one patient was lost to follow-up. The one patient with a type III fracture obtained a solid fusion within 3 months. One patient had the fusion revised at 1 month for progressive displacement; otherwise there were no notable complications. It is almost impossible to determine whether the fracture fragments had united but this is not important as long as there is a solid fusion. Whether treatment of acute odontoid fractures, particularly type II, should be operative or nonoperative is controversial, but from this review the authors believe that primary treatment of type II odontoid fractures by posterior atlantoaxial arthrodesis with its low morbidity and high fusion rate is superior to nonoperative treatment.

Accidents, Traffic↗