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PubMed1996

[Osteosynthesis of the odontoid process by a clover-shaped plate].

UNLABELLED: The goal was to design an osteosynthesis material able to stabilize after reduction a fracture of the odontoid process without C1-C2 arthrodesis. MATERIAL AND METHODS: The implant comprises a clover shaped plate which has to be applied on one hand on the anterior face of the dens (one leaf), and on the other hand on the anterior face of C3 (2 leaves are applied with a screw one screw for each leaf). A barrel fastened to the 3 leaves (implanted on the anterior face of the leaves, at their junction) gives way to a vertically oriented screw which will carry out dens fixation. The screw makes the compression possible. Placement through a pre-sterno-mastoid-approach, needs a special plate support and 18/10 Kirchner pins preparing the passage of the screw. RESULTS: This screw-plate designed for dens fractures (especially those with anterior displacement incompatible with a simple screwing) led to bone union in all cases. A C2-C3 subluxation operated on with the same technique was reduced and stabilized: a C2-C3 ankylosis was the consequence of a C2-C3 arthrodesis combined with the osteosynthesis. No complication was observed. DISCUSSION AND CONCLUSION: This technique is the only one able to perform dens osteosynthesis without implying postoperative immobilization. It is a significant advantage in elderly or multitrauma patients. A part from dens fractures, it can also help to manage dislocations, subluxations and serious C2-C3 sprains and even combinations as fractures of the odontoid process with axis pedicles fractures.

Bone Plates↗
PubMed1995

Management of type II odontoid process fractures in geriatric patients; a prospective study of sequential cohorts with attention to survivorship.

After institutional review defined an unacceptable mortality rate in nonoperative treatment of elderly patients with odontoid process fracture without neurological deficit, we undertook a prospective study to determine the influence of early surgical stabilization on perioperative mortality in geriatric odontoid process fracture patients without neurologic injury. Analysis suggests that acute perifracture mortality in this high-risk group can be significantly decreased and potentially eliminated by this approach.

Aged↗
PubMed1996

Ganglion cyst of the odontoid process. Case report and review of the literature.

STUDY DESIGN: This case report illustrates that although it is rare, a ganglion cyst can occur intraosseously in the odontoid process. OBJECTIVES: The tissue diagnosis was established by surgical resection of the cyst membrane and evacuation of the cyst content. The patient tolerated the procedure well, and the hospital course was uneventful. SUMMARY OF BACKGROUND DATA: Synovial cyst of the spine is uncommon and is usually found in the lumbar region. Its occurrence in the cervical spine is rare, and no cases in the odontoid process, to the authors' knowledge, have been reported. METHODS: This patient was evaluated initially for neck pain, which led to radiographic studies depicting the lesion. It raised the suspicion of metastatic neoplastic process, although the search for primary source proved to be negative. A biopsy was indicated. RESULTS: Surgical findings consisted of mucoid material field cavity lined by a thin membrane. The cyst was excised, and pathologic evaluation confirmed the diagnosis of synovial cyst. CONCLUSION: The correct radiographic diagnosis of this patient was not made because of lack of experience with such lesions in this location. The authors hope that this case report helps raise the awareness of clinicians in considering this diagnosis when facing similar radiographic presentation.

Aged↗
PubMed1991

Aneurysmal bone cyst of the odontoid process: case report.

Aneurysmal bone cysts (ABCs) are relatively uncommon, benign lesions. Fully 50% occur in long bones and 20% in the vertebral column, mostly in patients under 20 years of age. We report a case of an ABC in the odontoid process of a 74-year-old who sought treatment for pain and myelopathy. This is the first case reported of an ABC of the odontoid process.

Aged↗
PubMed1996

Fractures of the odontoid process in small children: biomechanical analysis and report of three cases.

Odontoid "fractures" in young children typically involve the cartilaginous plate (synchondrosis) that separates the odontoid process from the body of the axis; 58 cases have been described in the literature. We report two cases in which 2-year-old children were involved as backseat passengers in head-on motor vehicle accidents, both were restrained by four-point child's seat harnesses. A biomechanical investigation was carried out using simulation in a real car crash test with a child dummy. This revealed that head-on collisions with a speed absorption of at least 40 km/h are the typical mechanism of injury in children under the age of 3 years involved in motor vehicle accidents. Shearing force is all that is necessary to explain the dens fracture. Both children were immediately symptomatic, and the diagnosis was obvious on radiographs. Neither child had neurological deficit, which correlates well with the literature, where neurological injuries were found only in conjunction with head injuries. After closed reduction, both cases were initially treated conservatively with halo and plaster vest for 12 weeks. In one case, in which the anterior dislocation was less than the diameter of the odontoid shaft, eventless healing occurred. In our second case, despite an anatomic reduction, the odontoid fracture failed to unite. After a temporary posterior fixation of C1/C2 we reamed the synchondrosis from anterior and performed autogenous bone grafting. The posterior fixation wire was removed after 5 months. In contrast to the literature, we do not recommend a permanent posterior fusion of C1/C2. Our two young patients were both followed-up for more than 3 years. Clinical and radiological examination at final follow-up was normal with no signs of atypical growth of the odontoid. In cases of major dislocation with greater instability we recommend primary open reduction and osteosynthesis with appropriate implants. This was done in a third case: a 1 1/2-year-old boy who fell down the stairs and sustained a head injury and an unstable lesion of the odontoid with subtotal paraplegia. The odontoid was fixed with two screws.

Biomechanical Phenomena↗
PubMed1992

Intra-operative screw trimming in direct screw fixation of the odontoid process fracture--technical note.

For a satisfactory direct screw fixation of fractures of the odontoid process it is necessary to use a screw of the proper total length and thread length, but such an optimal ready-made screw is not always available. The authors describe a technique of intra-operative screw trimming using a high-speed diamond drill. This adjustment is easily and quickly performed. It enables the screw to act as a compression screw, which facilitates fusion of the fractured surfaces.

Bone Screws↗
PubMed1986

Experience in the management of odontoid process injuries: an analysis of 128 cases.

The authors present a retrospective analysis of 128 cases of odontoid process injury treated at the University of Minnesota and affiliated hospitals between the years 1967 and 1983. Of these 128 cases, 110 were acute fractures, while 18 patients suffered from old, unstable odontoid injuries. Motor vehicle accident was the leading cause of injury, and the largest group of patients was in their second decade. Type II fractures were the most commonly encountered type of injury, and anterior subluxation was the most common displacement. Posterior subluxation, however, had the highest incidence of associated neurological deficit. Regarding treatment, the 110 acute fracture patients fell into the following groups: 16 patients died during the acute phase, 14 patients underwent early posterior cervical fusion, and 80 patients underwent a course of external skeletal fixation. The remaining 18 patients with old unstable injuries underwent posterior cervical fusion. An analysis of the results in these groups led to the elucidation of certain factors that likely are important in determining the treatment of each individual patient. These factors include age of the patient, type of odontoid fracture, direction and degree of fracture displacement, and diagnostic delay. Fracture reduction and halo immobilization are the treatments preferred for patients who are diagnosed within 1 week of injury, who are less than 65 years of age and who have anteriorly, nondisplaced, or minimally posteriorly subluxed (less than 2 mm) Type II fractures, or who have any Type III injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1981

[Fracture of the odontoid process (author's transl)].

102 cases of fractures of the odontoid process have been seen by the author - 73 recent cases and 29 old ones. It was important to distinguish basal fractures (29 cases), which all united after conservative treatment by reduction and skull traction for six weeks followed by a plaster cast for six to eight weeks, and fractures of the body (44 cases). 41 body fractures were treated conservatively, of which 6 died and only 20 united. The authors consider that treatment by skull traction must always be tried. An eventual indication for surgery can be made at about the 20th day if displacement is found to be present in spite of treatment. Fusion in these cases must be limited to C1-C2. It is best obtained by a combination of wiring and grafting.

Adolescent↗
PubMed1994

Fractures of the odontoid process: analysis of the functional results after surgery.

Eighteen patients who sustained type II/III fractures of the odontoid process, as classified by Anderson and D'Alonzo [2], underwent anterior screw fixation, as described in detail by Böhler [4] as well as Grob and Magerl [16]. Follow-up investigations 3, 12 and in some cases up to 60 months later confirmed sufficient functional results regarding the mobility of the upper cervical spine. The passive mobility of the cervical spine was analyzed by the radiographic evaluation technique of Dvorak and co-workers [12] and Penning [26], which revealed a hypomobility of the C2-3 segment 1 year after surgery in 11 patients and a fusion of the C2-3 vertebral bodies in 2 cases. The postoperative results including the rate of complications were compared with other authors's findings and different therapy concepts (e.g., posterior C1-2 arthrodesis, halo-vest treatment).

Adolescent↗
PubMed1994

A new appraisal of abnormalities of the odontoid process associated with atlanto-axial subluxation and neurological disability.

It is well known that abnormalities of the odontoid process may be associated with subluxation and neuraxial compression. Modern computerized imaging is demonstrating that existing classifications are in need of revision since they no longer reflect current views on development, nor do they adequately explain the patterns of abnormality commonly encountered in clinical practice. This study is a description of 62 varied clinical cases examined by high definition computerized myelography or MRI in flexion and extension, some before and after stabilization procedures. From these descriptions, and a review of the old and more recent literature concerning phylogenesis and ontogenesis of the odontoid, the following conclusions were drawn. The dens within the atlas ring is not morphologically a centrum of the first cervical vertebra, but a projection arising from it. In os odontoideum the dens forms normally, but ossifies abnormally because of abnormal motion; it is a result rather than the cause of instability. Hypoplasia of the dens is usually incorrectly diagnosed. When present it is associated with atlanto-occipital assimilation, fusion of the second and third, or more, cervical vertebrae, loss or reduction in axial rotation of the head, basilar invagination and hindbrain deformity of Chiari type. Therefore it is part of a regional anomaly involving hypoplasia of the derivatives of the occipital and upper cervical somites. Recognition of these aspects simplifies both diagnosis and the formulation of therapeutic strategies for different types of clinical presentation.

Adolescent↗
PubMed1992

The signal intensity of the normal odontoid process (dens) displayed on magnetic resonance images.

In order to analyse the normal signal intensity of the medullary space of the odontoid process (dens) relative to age, the craniovertebral junction of 33 asymptomatic volunteers in six age groups was examined by means of magnetic resonance imaging. To avoid partial-volume effects 3-mm slices were used in sagittal and axial planes. The signal intensities relative to cerebral white matter varied from 0.51 to 1.23 in the sagittal plane and 0.56 to 1.51 in the axial plane. The signal intensities relative to muscle varied from 0.76 to 2.40 in the sagittal plane and 0.96 to 2.30 in the axial plane. The signal intensities relative to fat varied from 0.22 to 0.62 in the sagittal plane and 0.23 to 0.68 in the axial plane. No correlation with age of the volunteers was found. The normal medulla of the dens may exhibit a low signal intensity on T1-weighted images irrespective of age.

Adipose Tissue↗
PubMed1992

[Fresh fracture of the odontoid process treated with direct screw fixation; a case report].

A case of a fresh type II fracture (Anderson & D'Alonzo) of the odontoid process treated with direct screw fixation is reported. A 52-year-old man complained of severe neck pain following a hit on his forehead incurred in a falling accident. Neurological examination was normal. Cervical spine x-ray films and axial CT scans revealed a fracture at the base of the dens. It was slightly oblique leftup and rightdown, and the dens fragment was displaced 3mm lateral to the right. One week after the injury, this odontoid fracture was directly fixed with a compression screw by an anterior cervical approach. Immediately after the operation, his neck pain disappeared. He had only 4 days of bed rest and 2 months of external immobilization with a simple neck collar. He returned to his previous job 2 months after surgery without any limitation of his neck movement. At follow-up examination 16.5 months after the operation, x-ray films demonstrated complete fusion of the fracture and no problem about the screw such as displacement or breakage. Direct screw fixation of an odontoid fracture via a transcervical approach was thought to be a reasonable method of treatment. For proper assembly of this method, the following two points are particularly recommended: a screw insertion perpendicular to the fracture plane and the use of an optimal screw with both the desired total and thread lengths.

Bone Screws↗
PubMed1988

Odontoid process fracture osteosynthesis with a direct screw fixation technique in nine consecutive cases.

The authors present their experience with surgical treatment of odontoid process fractures using a direct screw fixation technique via an anterolateral retropharyngeal approach. Nine consecutive patients have been operated on with this technique. There were two deaths unrelated to the surgery, and anatomical union with conservation of the craniospinal hinge mobility was achieved in the remaining seven patients. The direct screw fixation technique appears feasible, efficient, and logical.

Adult↗
PubMed1976

[Fractures of the odontoid process of the axis].

Analysis of 15 cases of fracture of the odontoid process of the axis, with a follow-up time of 18 months to 9 years. In 6 cases (40 p. 100) the diagnosis of the fracture was made with a delay extending from one week to 3 months after the accident. The only case complicated with neurological findings was a fracture of the dens without radiological displacement. All patients have been treated conservatively. Twelve fractures united after 4 to 6 months immobilisation. In two cases a tight and stable non-union has developed. In only one case the pseudarthrosis was loose and unstable, and required a surgical fusion. The functional result was dominated by a restriction of movements of the head, variable in its importance, but practically constant.

Adolescent↗
PubMed1988

The odontoid process in children--is it hypoplastic?

An analysis of the cervical spine of 508 normal children aged between 3 and 18.9 years provided data for the normal development of the odontoid process and its relationship to the anterior arch of the atlas. In normal children under the age of 9 years, the tip of the odontoid may fall well short of the upper margin of the anterior arch of the atlas. This has important implications for the assessment of atlanto-axial instability in children with Down's syndrome.

Adolescent↗
PubMed1988

Treatment in fractures of the odontoid process.

Fifty-eight cases of odontoid fractures treated at Keio University Hospital and affiliate hospitals from 1965 through 1985 were reviewed. Six patients under age 7 years (group A), were characterized as having epiphysiolysis. Among 52 patients over 8 years of age (group B), there were two Type I, 31 Type II and 19 Type III fractures. All cases in group A were treated conservatively by a plaster cast or a neck brace, and achieved bony union in 6 to 27 weeks. Five of 24 fractures in group B, treated conservatively, failed to unite. Nineteen cases of Type II and six cases of Type III were treated surgically. Transoral fusion was performed in six cases, internal fixation using a compression screw in ten, bone peg fixation in one, posterior fusion in eight, and posterior decompression in one. Two cases treated with transoral fusion and two with screw fixation failed to unite. We recommend conservative treatment of group A patients, Type I, and acute cases of Type III with minimal displacement in group B. Surgery should be performed in acute cases of Type II, Type III with significant displacement, and nonunion cases in Type II and Type III.

Adolescent↗