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PubMed1983

Fractures of the arches of the atlas: a study of their causation.

The autopsy findings in 32 accidental deaths which showed fracture(s) of the arches of the atlas have been correlated to reconstructions of the course of events in the accidents. Flexion of the head causing fracture(s) of the neural arch or odontoid process of the axis also resulted in fracture(s) of the posterior arch due to downward traction. Extension of the head causing fracture of the odontoid process of the axis gave rise to fractures of the posterior arch due to pressure from below. Tilting of the head caused marginal fractures of the anterior arch due to oblique traction. Tilting of the head also caused fracture(s) of the anterior and/or posterior arch due to transverse extension of the atlas ring and/or superior dislocation of one lateral mass in relation to the other. Oblique flexion or extension of the head resulted in similar fractures. Flexion of the head with some rotation combined with compression of the neck can cause the anterior margin of one upper joint surface of the axis to act as a wedge separating the anterior arch of the atlas from below. Extension of the head with some rotation combined with compression of the neck can lead to a fracture running through one lateral mass due to its tilting-dislocation in posterior direction. It is striking that there was no fracture of the atlas which could be ascribed to a simple and symmetric compression of the neck (classical Jefferson's fracture).

Accidents, Traffic↗
PubMed1987

Systemic mastocytosis, an unusual cause of osteoporosis.

A 45-year-old patient is described presenting with severe axial osteoporosis. The presence of maculopapular skin lesions and the combination of osteolytic and osteoblastic bone lesions led to the tentative diagnosis of systemic mastocytosis. This diagnosis was confirmed by measurement of urinary histamine metabolites and by bone biopsy showing increased numbers of mast cells and fibroblast-like cells. The importance of these diagnostic procedures in this rare cause of osteoporosis is discussed.

Axis, Cervical Vertebra↗
PubMed1994

Osteoid osteoma of the axis.

A 15-year-old boy suffering from osteoid osteoma of the right lamina of the axis presented with torticollis and local pain without neurological deficits. The tumour was treated by en-bloc resection and laminoplasty with autogenous iliac crest. The follow-up at 14 months showed complete pain relief and a perfect incorporation of the transplanted bone.

Adolescent↗
PubMed1986

Foramen magnum stenosis in homozygous achondroplasia.

A 4-month-old female with homozygous achondroplasia and daytime apnea was found to have a small foramen magnum by computerized tomography. Following suboccipital craniectomy and C1-C2 laminectomy respiratory problems did not recur during a 7 month post-operative period. We suggest that the respiratory problems in homozygous achondroplasia may be due to brainstem compression from an abnormally small foramen magnum.

Achondroplasia↗
PubMed2002

[Pathomorphology, diagnosis and treatment of "hangman's fractures"].

In a retrospective study diagnostic procedures and outcome of treatment were evaluated in 33 patients with traumatic spondylolisthesis of the axis (Hangman's fracture) who were treated in our department between 1986 and 1999. There were 18 men and 15 women with an average age of 41 (17-88) years. The cause of the injury was in 23 cases an accident as a driver of a car, in 2 cases an accident with a bike, 2 patients had an accident as a pedestrian. 5 patients fell on their head and 1 patient was hit by a beam. In 15 cases there were relevant accompanying injuries. To assess the stability of the injury, a subtle radiological examination was performed including functional X-rays. After introduction of the MRI and increasing experience with the method as a standard procedure in clinical practice it was used instead of functional X-rays to get a direct image of the involvement of the discoligamental structures.17 patients with stable lesions were treated conservatively, 15 with a Minerva-cast, 2 with a halo-jacket. One polytraumatized patient had temporary immobilization with a stiff-neck. 16 patients with discoligamental instability C2/3 were treated operatively by Robinson-spondylodesis with additional anterior plating. In one case an additional posterior fusion was necessary. After 6-8 weeks all of the conservative treated patients achieved solid bony consolidation. The patients operated on did so as well within 6 to 8 weeks. Two polytraumatized patients died. 18 of the 31 surviving patients were free of pain. 12 patients complained of pain or tension of the cervical muscles during physical stress. 1 patient suffered of paresthesia of the ulnar left hand. Average duration of hospital stay was 12,9 days (1-47). All working people returned to their job. Differences in the outcome of the conservative and the operative treatment group could not be seen. We derive from these results that Hangman's fractures, mostly caused by a hyperextension trauma, achieve solid bony fusion by conservative treatment in most of the cases. The Minerva-cast has proved its capability. In cases of instable luxation fractures including tearment of the anterior longitudinal ligament and affection of the intervertebral disc C2/3 we suggest operative stabilization. We prefer the modified Robinson-spondylodesis with additional anterior plating which proved its value as a method achieving solid bony fusion combined with low rate of complications.

Adolescent↗
PubMed2003

[Traumatic atlanto-axial rotatory fixation with lateral mass fracture of the axis].

Traumatic atlanto-axial rotatory fixation (AARF) is a relatively uncommon injury, especially in association with fractures of the axis. The rotatory dislocation and fixation is normally caused by intercalated facet joints of axis and atlas. A traumatic AARF in a 21 year old female is presented with special emphasis on the diagnostic and therapeutic approaches. This high velocity injury was caused by a traffic accident. The trauma service which was initially involved made the correct diagnosis and tried to reduce the dislocation by skull traction during analgesia and sedation, but without success. For further treatment, the patient was referred to a level one trauma center. After completing the diagnostic imaging with MRI and CT for exact delineation of the fracture site and determination of ligament damage, a halo fixation for skull traction was installed. This second attempt was also unsuccessful. Only a closed reduction under general anesthesia with muscle relaxation led to a neutral alignment and congruent joint contact between C1 and C2. Due to the stable fracture site and the intact ligaments, a conservative treatment with a stable collar splint was performed.

Accidents, Traffic↗
PubMed2006

[Injuries to the craniocervical junction].

Injuries to the upper cervical spine (C0-C2) play a major role in surgical treatment of traumatic sequelae in the entire cervical spine. Even though the number of such operations has increased in recent years, there are no clear treatment recommendations for most types of cervical spine injuries. In view of the wide range of injury types and the correspondingly large number of treatment options, this review focuses mainly on the following types of injuries: C0 fractures, occipital condyle fractures (OCF), atlanto-occipital dislocation (AOD), atlas fractures, atlantoaxial dislocation (AAD), and axis fractures. Important aspects of the mechanisms of injury, clinical signs and symptoms, diagnostic procedures, and treatment options are discussed. Special emphasis is placed on comparatively reviewing the different treatment options discussed in the literature. A summary in table form is presented at the end of each chapter for quick reference.

Adolescent↗
PubMed1999

[Traumatic spondylolisthesis of the axis].

In common the traumatic spondylolisthesis is not a life threatening injury. An exact diagnosis is mandatory as well as a differentiated therapy. Especially the correct decision about the therapy (operative vs conservative) including the technical demanding operative procedures is based on an experienced surgeon. These patients should be transferred to a specialised centre.

Axis, Cervical Vertebra↗
PubMed2000

Low-frequency otolith and semicircular canal interactions after canal inactivation.

During sustained constant velocity and low-frequency off-vertical axis rotations (OVAR), otolith signals contribute significantly to slow-phase eye velocity. The adaptive plasticity of these responses was investigated here after semicircular canal plugging. Inactivation of semicircular canals results in a highly compromised and deficient vestibulo-ocular reflex (VOR). Based on the VOR enhancement hypothesis, one could expect an adaptive increase of otolith-borne angular velocity signals due to combined otolith/canal inputs after inactivation of the semicircular canals. Contrary to expectations, however, the steady-state slow-phase velocity during constant velocity OVAR decreased in amplitude over time. A similar progressive decrease in VOR gain was also observed during low-frequency off-vertical axis oscillations. This response deterioration was present in animals with either lateral or vertical semicircular canals inactivated and was limited to the plane(s) of the plugged canals. The results are consistent with the idea that the low-frequency otolith signals do not simply enhance VOR responses. Rather, the nervous system appears to correlate vestibular sensory information from the otoliths and the semicircular canals to generate an integral response to head motion.

Animals↗
PubMed1999

Marked non-uniformity of fiber-type composition in the primate suboccipital muscle obliquus capitis inferior.

Obliquus capitis inferior (OCI) is a monoarticular suboccipital muscle linking the transverse process of the atlas (C1) to the spinous process of the axis (C2). Histochemical analysis of fiber-type composition showed that the muscle has a marked gradient of fiber-type distribution in which type I fibers comprise 95-100% of fibers in the deepest region but less than 10% of fibers in the superficial layer. Step-like changes in fiber-type proportions occurred between groups of fascicles. In most instances the boundaries between these fascicles did not exhibit different perimysial features from those fascicles with similar fiber-type proportions. OCI contained large numbers of muscle spindles, which were concentrated in deep regions rich in type I fibers. The degree of nonuniformity in fiber-type distribution seen in OCI is unusually large when compared with patterns described in other primate muscles, and has implications for the way that the muscle is studied anatomically and physiologically.

Adenosine Triphosphatases↗
PubMed1999

Three-dimensional organization of vestibular-related eye movements to off-vertical axis rotation and linear translation in pigeons.

During linear accelerations, compensatory reflexes should continually occur in order to maintain objects of visual interest as stable images on the retina. In the present study, the three-dimensional organization of the vestibulo-ocular reflex in pigeons was quantitatively examined during linear accelerations produced by constant velocity off-vertical axis yaw rotations and translational motion in darkness. With off-vertical axis rotations, sinusoidally modulated eye-position and velocity responses were observed in all three components, with the vertical and torsional eye movements predominating the response. Peak torsional and vertical eye positions occurred when the head was oriented with the lateral visual axis of the right eye directed orthogonal to or aligned with the gravity vector, respectively. No steady-state horizontal nystagmus was obtained with any of the rotational velocities (8-58 degrees /s) tested. During translational motion, delivered along or perpendicular to the lateral visual axis, vertical and torsional eye movements were elicited. No significant horizontal eye movements were observed during lateral translation at frequencies up to 3 Hz. These responses suggest that, in pigeons, all linear accelerations generate eye movements that are compensatory to the direction of actual or perceived tilt of the head relative to gravity. In contrast, no translational horizontal eye movements, which are known to be compensatory to lateral translational motion in primates, were observed under the present experimental conditions.

Animals↗
PubMed2000

Management of craniocervical junction dislocation.

The discovery of a craniocervical junction malformation requires management in three steps: (1) The patterns must be recognized using tomographic measurements (Chamberlain's line, Wackenheim's line). Dynamic flexion-extension studies are necessary to assess stability or instability. Stable patterns range from platybasia to basilar invagination, with gradual deformation, and are frequently associated with Chiari malformation. Unstable patterns characterized by odontoid instability are the equivalent of an odontoid fracture. The origin is malformative (hypoplasia, aplasia of the dens, os odontoidum), but the last may be difficult to distinguish from an old odontoid fracture. They are found in many syndromes (Down, Morquio, etc.). Unstable atlantoaxial patterns with atlas assimilation are hardly reducible; they evolve toward progressive instability. (2) The neurological consequences must be defined from the clinical features of the spinal cord and the cranial nerves. Both static and dynamic MRI scans must be performed; in this way identification of the neural abnormalities (hydromyelia, Chiari, etc.) and of the osseous compression is possible. (3) The most appropriate operative procedure must be selected: stable platybasia with a nervous compression by Chiari is cured only by posterior decompression; odontoid instability is cured by reduction and posterior fixation, using hooks and autologous bone grafts on the posterior arches of C-1 and C-2. Sometimes a transarticular screw fixation of C1-2 is necessary if there is a defect on the C-1 posterior arch. Craniocervical dislocations with assimilation of the atlas require posterior occipito-vertebral bony fixation with grafts and external halo immobilization or internal fixation with hooks or screws, with anterior transoral decompression in a second step.

Arnold-Chiari Malformation↗
PubMed2002

Excision of an osteoid osteoma from the body of the axis through an anterior approach.

Osteoid osteoma is seen less commonly in the vertebral body than in the posterior elements of the spine. To the authors' knowledge, this is only the second reported case of an osteoid osteoma affecting the body of the axis. The patient described in this report presented with the classic symptomatology of pain and torticollis. Radiological imaging confirmed the diagnosis. A superior extension of the anterior Smith-Robinson approach, through the "window of access" described by Fasel, was used to excise this lesion. Following surgical excision, there was complete resolution of the presenting symptomatology and functionally the range of motion of the cervical spine returned to normal. We avoided instrumentation and C1-C2 fusion so that rotation of the cervical spine could be maintained. There were no signs of recurrence of the tumour within the 4-year follow-up period. It presented in a classic way but, despite this, it took 2 years from the onset of these symptoms to reach a definitive diagnosis. This osteoid osteoma was successfully excised through a superior extension of the anterior Smith-Robinson approach.

Adolescent↗
PubMed2004

Headache due to an osteochondroma of the axis.

We reported a case of a 42-year-old man with a 3-year history of headache due to a spinal osteochondroma. Repeated neurological evaluation, including EEG studies and CT of the cerebrum, revealed no pathology. More recently the patient presented with persistent headache and a slight limitation of neck motion. MRI studies of the cerebrum including the cervical spine showed a high cervical extradural tumor. Additional CT angiography showed a bony tumor suspected of being a spinal osteochondroma. An en bloc resection of the tumor was performed; histological evaluation confirmed the diagnosis. Immediately after intervention, all symptoms disappeared. In most patients with a spinal osteochondroma, the lesion causes no symptoms, or symptoms are aspecific. Therefore, there is often a significant delay between initial complaints and the diagnosis, as in the current case.

Adult↗
PubMed2004

Therapeutic options and results following fixed atlantoaxial rotatory dislocations.

Atlantoaxial rotatory dislocation (AARD) represents a rare pathological condition of the upper cervical spine that is frequently misdiagnosed, leading to a delay in therapy. In a long-term assessment of clinical and radiological results, three different therapeutic options with regard to the length of the dislocation-therapy interval (DTI) were evaluated. Twenty-six patients were treated for AARD from December 1988 until April 2000. Proper diagnosis was established after an average interval of 15 months. Three different therapeutical protocols were followed in order to reduce the dislocation: (1) closed transoral reposition under general anesthesia; (2) temporary transoral fixation utilizing the Harms T-plate; (3) definitive transoral fusion. The eight patients treated by closed reduction had the best pain relief. The average visual analogue scale (VAS) score was 96.6 points, while the rotatory motion of the upper cervical spine, as assessed by dynamic MRI, was 25.3 degrees to each side. The length of the dislocation-therapy-interval (DTI) averaged 1.4 months. A mean VAS Score of 92.3 points was recorded in the ten patients treated with a temporary fixation of C1/C2. In this subgroup the DTI had an average length of 5.3 months. The mean rotation to each side was 13.9 degrees . In the eight patients who underwent definitive fusion the mean VAS score was 60.6 points, while the average length of the DTI was 40.5 months. In conclusion, the clinical outcome and the subjective well-being following AARD deteriorates with increasing length of the dislocation-therapy interval.

Adolescent↗
PubMed2005

Os odontoideum with bipartite atlas and segmental instability: a case report.

We report on the case of a 15-year-old adolescent who presented with a transient paraplegia and hyposensibility of the upper extremities after sustaining a minor hyperflexion trauma to the cervical spine. Neuroimaging studies revealed atlantoaxial dislocation and ventral compression of the rostral spinal cord with increased cord signal at C1/C2 levels caused by an os odontoideum, as well as anterior and posterior arch defects of the atlas. The patient underwent closed reduction and posterior atlantoaxial fusion. We describe the association of an acquired instability secondary to an os odontoideum with an anteroposterior spondyloschisis of the atlas and its functional result after 12 months. The rare coincidence of both lesions indicates a multiple malformation of the upper cervical spine and supports the theory of an embryologic genesis of os odontoideum.

Adolescent↗