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At least 1,081 records · Page 60Linked to original sources
PubMed1997

Craniovertebral junction anomalies: diagnosis and management.

The craniovertebral junction is the most complex of the axial skeleton, residing between the skull and the upper cervical spine. Congenital, developmental, and acquired bony abnormalities result in compression and distortion of the neural structures, the vertebrobasilar vascular system, and the cerebrospinal fluid channels. The clinical significance of this has only been recently recognized, and mistaken diagnoses have led to a delayed treatment and at times adverse results. A review of the anatomy, the embryology, and the mechanics of this region is essential to the understanding of the pathophysiology encountered.

Atlanto-Axial Joint↗
PubMed1998

Safety and accuracy of transarticular screw fixation C1-C2 using an aiming device. An anatomic study.

STUDY DESIGN: In this anatomic study, the safety and accuracy of C1-C2 transarticular screw placement was tested in a normal anatomic situation in cadaver specimens using a specially designed aiming device. OBJECTIVES: To assess the safety and accuracy of transarticular screw placement using the technique described by Magerl and a specially designed aiming device. SUMMARY OF BACKGROUND DATA: Transarticular C1-C2 screw fixation has been shown to be biomechanically superior to posterior C1-C2 wiring techniques. Several clinical series have been reported in the literature. However, no previous study assessing the accuracy or safety of this technique has been published. Structures at risk are the vertebral arteries, spinal canal, and the occiput-C1 joint. METHODS: Five frozen human cadaveric specimens were thawed and instrumented with 10 C1-C2 transarticular screws, according to the technique described by Magerl but using a specially designed aiming device described by the senior author (Jeanneret). After screw placement, the accuracy of screw positioning and the distance of the screws from the spinal canal, vertebral arteries, and atlanto-occipital joint were determined by anatomic dissection and radiographic analysis. RESULTS: The structure at greatest risk was the atlanto-occipital joint, with one screw found to be damaging the joint. Vertebral artery or spinal canal penetration was not observed in any of the specimens. Screw length averaged 45 mm and, with proper length, the screw tip was found to be located approximately 7.5 mm behind the anterior tubercle of C1 on lateral radiographs. CONCLUSIONS: This anatomic study demonstrates that C1-C2 transarticular screw fixation can be performed safely in a normal anatomic situation by surgeons who are familiar with the pertinent anatomy. The aiming device allowed safe instrumentation in all patients. In case of an irregular anatomic situation (e.g., congenital abnormalities or trauma), computed tomographic scan with sagittal reconstruction is recommended-in particular, to obtain information about the course of the vertebral artery.

Axis, Cervical Vertebra↗
PubMed2005

Anatomic considerations for the pedicle screw placement in the first cervical vertebra.

STUDY DESIGN: Anatomic bony measurements were manually performed on 50 dry atlantoaxial vertebral complexes with an electronic digital caliper, and a reliable landmark for insertion of a pedicle screw in C1 vertebra was described and evaluated. OBJECTIVES: To investigate the feasibility of placing a screw in the C1 pedicle and evaluate the reliability of the C2 lateral mass as a landmark for determining the optimal site of screw entry. SUMMARY OF BACKGROUND DATA: The use of C1-C2 pedicle screws with the additional rods or plates has been an alternative method of stabilization for patients who are unsuitable for C1-C2 transarticular screw stabilization. However, the optimal portal of entry for the C1 pedicle screw is difficult to determine during surgery in the absence of reliable reference landmarks and sufficient relevant anatomic studies. METHODS: We manually measured 11 linear anatomic parameters related to the C1 lateral mass, its pedicle and posterior arch under the groove on 50 pairs of dry C1-C2 complexes harvested from cadavers. We also treated five patients with atlantoaxial instability with C1 and C2 pedicle screw fixation; the entry point of the C1 pedicle screw was ascertained by using C2 lateral mass as a landmark, and the position of the C1 pedicle screws in each case was evaluated with postoperative radiographs and computed tomography scans. RESULTS: The mean mediolateral width and rostrocaudal height of C1 pedicle were 8.57 and 5.83 mm, respectively. The mean rostrocaudal height of C1 posterior lamina at the reference entry point for the screw was 4.59 mm. The mean rostrocaudal height of the C1 posterior arch under the vertebral artery groove was 3.88 mm at its medial one-third and 4.25 mm at its lateral one-third. The thinnest external diameter of the screw tract that was recorded was <4 mm in six (12%) specimens of C1 vertebrae. The center of C2 lateral mass was 1.51 mm lateral to the sagittal plane of the mediolateral midpoint of the C1 pedicle. The distance from the suggested screw entry point to C1 posterior tubercle was 22.15 mm, and the mean length of the screw tract was 28.55 mm. Ten C1 pedicle screws were placed exactly, without neural or vascular injury in all five patients. CONCLUSION: The heights of the C1 pedicle, the posterior arch under the groove and the posterior lamina at the screw entry point are the major determinants for the possibility of placing pedicle screws in C1 of a given patient. This study indicates that it is feasible to place a 3.5-mm pedicle screw safely in C1 in most patients, and the lateral mass of C2 is a reliable anatomic landmark that can be easily identified to help the surgeon determine the optimal screw entry portal conveniently during surgery.

Adult↗
PubMed1980

Query rabies.

Explore the source record for details and available documents.

Animals↗
PubMed1975

Surgical treatment of the symptomatic unstable cervical spine in rheumatoid arthritis.

In rheumatoid arthritis spontaneous subluxation of cervical vertebrae is not infrequent and can usually be managed by conservative treatment. Surgical treatment, however, is necessary when there is neural involvement. Of twelve patients who had spine fusion for atlanto-axial subluxation only six had solid union. When conservative treatment fails, reduction by halo traction and arthrodesis of the cervical spine is the method recommended, but the best method of post-operative care remains uncertain. In these patients postoperative immobilization was provided by various methods, including a halo cast or brace, but no method appeared to be superior.

Adolescent↗
PubMed1991

Familial cervical dysplasia.

Nine of twelve family members from three generations were affected by an inherited form of cervical vertebral dysplasia. All of the affected people had an abnormality of the first cervical vertebra. Some also had defects of the axis and caudad to it. The mode of transmission of the disorder is autosomal dominant, with apparently complete penetrance and variable expressivity. Two patients had symptoms. One had a passively correctable tilt of the head, with an associated audible clunk and hypoplasia of the left superior facet of the second cervical vertebra. This patient had no local symptoms, neurological involvement, or muscle spasm. In the other patient, suboccipital pain developed. Radiographs revealed an anterior atlanto-occipital dislocation. The symptoms resolved after reduction and arthrodesis. Because of the apparently complete penetrance of this disorder, physicians caring for patients who have this type of congenital malformation of the cervical spine should consider examination of closely related members of the family. Clinical findings such as tilting of the head, torticollis, or limitation of cervical motion suggest that additional evaluation should be done. The examination should include lateral radiographs of the cervical spine in flexion and extension. Three-dimensional computed-tomography reformatting was helpful in demonstrating the complex cervical anatomy in our patients. Patients who have recognized abnormalities should be followed and should be re-examined whenever local or neurological symptoms develop. A magnetic resonance image of the spine in flexion and extension was valuable for identification of the potentially disastrous situation of impending damage to the cord in patients who had instability and evolving symptoms.

Adult↗
PubMed1977

Dysplasia of the odontoid process in Morquio's syndrome causing quadriparesis.

Eleven patients with documented Morquio's syndrome who had dysplasia of the odontoid process and resulting atlanto-axial instability were reviewed. They were found to be at risk for acute traumatic quadriparesis, chronic myelopathy of a variable and often rapid rate of progression, and sudden death by respiratory arrest. The evidence suggests that early prophylactic posterior cervical fusion is indicated for patients with this malformation and that once quadriparesis is established, recovery of function is limited.

Adult↗