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PubMed2000

A six year review of odontoid fractures: the emerging role of surgical intervention.

BACKGROUND: Traditionally, odontoid fractures have been treated with different bracing techniques resulting in variable degrees of successful healing. Surgical intervention is becoming more widely practiced as a primary intervention. The purpose of this report was to survey our recent experience in southern Alberta to determine potential outcome differences in management strategies. METHODS: We retrospectively reviewed the charts of 520 patients diagnosed with cervical spine fractures over a six-year period from January 1990, through December 1996. Patients were identified through the medical records database of the two Level 1 trauma facilities, on the basis of ICD-9 diagnostic coding. RESULTS: Ninety-three fractures of the odontoid process were identified, of which 85 were acute and eight were chronic. There were 57 Type II (67%) and 27 Type III (32%) acute odontoid fractures. Of these, 64 were managed conservatively (bracing), whereas 20 were treated surgically. Thirteen patients underwent anterior screw fixation, seven patients had posterior cervical fusion. Eleven patients died in the acute phase, two as a result of their high cervical cord injury and nine from unrelated medical causes. Fifty-six of the remaining 82 patients (68%) were located with a minimum of three months follow-up (range three months to eight years). Satisfactory results were obtained in 76% of all acute patients treated by bracing, but only 50% in those over the age of 65. In the surgically managed group, all patients (100%) went on to develop stable fusions. CONCLUSIONS: Our results indicate that while conservative management of odontoid fractures with external bracing results in fracture healing in most cases, surgical fusion may provide superior rates of bony union with acceptable morbidity. This difference in outcome lends itself to formal investigation through a prospective randomized trial.

Adolescent↗
PubMed1977

Congenital anomaly of the odontoid in children. A report of four cases.

The embryologic origins of congenital abnormalities of the odontoid process are reviewed. Four cases of odontoid dysgenesis in childhood are presented. All of our cases were associated with a head injury, which subsequently led to the diagnosis. Pain was the most common presenting complaint in our patients. Decreased cervical mobility was the most consistent physcial finding. There was no major neurological defect implicating spinal cord compression in any of our patients. This is not true of adults with congenital abnormalities of the odontoid, particularly those with atlantoaxial instability. The diagnosis of odontoid dysgenesis is a radiographic one. Flexion-extension films, tomograms and cineradiograms are often required to make the diagnosis. C1-C2 subluxation, either anterior or posterior is often found. Prompt posterior cervical fusion is recommended as the treatment of choice.

Axis, Cervical Vertebra↗
PubMed2002

Biomechanical comparison of four anterior atlantoaxial plate systems.

OBJECT: The optimum fixation method to achieve atlantoaxial fusion after resection of the odontoid process remains a matter of discussion. Anterior atlantoaxial plate fixation has been described by Harms as a fixation procedure to be performed after transoral odontoid resection. In recent biomechanical and clinical studies investigators have shown that this procedure is a good alternative to established posterior atlantoaxial fixation techniques, but they have also indicated the biomechanical disadvantages of the Harms plate design. Therefore, three new anterior atlantoaxial plate designs were developed. The purpose of this study was to compare these three newly designed plate systems biomechanically with that used in Harms anterior atlantoaxial plate fixation. METHODS: Twenty-four human craniocervical cadaveric specimens were tested in flexion, extension, axial rotation, and lateral bending in a nonconstrained testing apparatus by using a nondestructive stiffness method. Three-dimensional displacement of C 1-2 was measured with an optical measurement system. Six different groups were examined: 1) control (24 specimens); 2) unstable (after odontoidectomy and dissection of the atlantoaxial ligaments; 24 specimens); 3) Harms (anterior atlantoaxial plate fixation according to Harms; six specimens); 4) subarticular atlantoaxial plate (SAAP; six specimens); 5) transpedicular atlantoaxial plate (TAAP; six specimens); and 6) subarticular atlantoaxial locking plate (SAALP; six specimens). Stiffness, range of motion, and neutral and elastic zones were determined. Compared with the Harms plate, stiffness was significantly higher when methods for placing the SAAP, TAAP, and SAALP devices were used (p < 0.05). Angular displacement of SAALPs was less than that demonstrated in any other group (p < 0.05). Stiffness values in any direction were significantly greater for the SAALP-fixed specimens than for the TAAP, SAAP, Harms, control, or unstable specimens (p < 0.05). CONCLUSIONS: Experimentally, the SAAP, TAAP, and Harms plate achieved less stable fixation than the SAALP. Therefore, if transoral odontoid resection is performed, SAALP-fixed spines will provide significantly improved stability compared with previous fixation devices and methods. This may be a necessary prerequisite for a fast and uneventful osseous fusion even without additional posterior stabilization.

Aged↗
PubMed1998

The helical three-dimensional CT in the diagnosis of torticollis with occipitocondylar hypoplasia.

Congenital anomalies of the atlanto-occipital and atlantoaxial joints are rare. Those most commonly reported are atlantoaxial instability, basilar impression, anomalies of the odontoid process, laxity of the transverse atlantal ligament and atlanto-occipital fusion. Occipital condylar hypoplasia is infrequent and difficult to recognise. We recently diagnosed it using helical 3D CT in association with torticollis in two patients. The first patient had a several year history of torticollis. The second patient had acute cervical lymphadenitis associated with post-operative torticollis. 3D CT distinctly revealed atlantoaxial subluxation with hypoplasia of the occipital condyles in both cases.

Acute Disease↗
PubMed2001

Atlantoaxial stability in ossiculum terminale. Case report.

The authors describe a patient with ossiculum terminale. Thin-section three-dimensional computerized tomography reconstructions, magnetic resonance images, and radiographs of the cervical spine were obtained to evaluate the atlantoaxial stability and structures of the ossiculum terminale. Bone had formed between the ossicles and the body of the odontoid process, and good atlantoaxial stability was clearly demonstrated.

Adult↗
PubMed1999

Computed tomographic and magnetic resonance imaging of chronic odontoid fractures.

STUDY DESIGN: The analysis of the imaging characteristics found in chronic odontoid fractures. OBJECTIVES: To determine the efficacy of computed tomography and magnetic resonance imaging in diagnosing a chronic odontoid fracture. SUMMARY OF BACKGROUND DATA: Radiographic examination of the cervical spine is intrinsic to the evaluation of all patients with blunt trauma. Injury to the craniocervical junction constitutes 19-25% of all cervical spine fractures. At the authors' trauma center computed tomography is routinely used instead of the open-mouth odontoid radiograph to facilitate cervical spine evaluation. This practice has increased the detection of fractures that are unrecognized in plain radiography, and has, at the same time, raised questions about the age and significance of these fractures. METHODS: Radiography, computed tomography, and magnetic resonance imaging studies were performed on three patients who came to the emergency department with odontoid fractures. Two patients had a history of severe trauma, and one had a history inconsistent with an acute odontoid fracture. One patient also had a technetium Tc 99m methylene dihydroxyphosphonate bone scan. The studies were obtained to determine the age of the fractures. RESULTS: All three patients were determined to have chronic odontoid fractures. This diagnosis was facilitated by the use of computed tomographic and magnetic resonance imaging. Computed tomography showed increased sclerosis in the proximal fracture fragment in all cases and well-corticated fracture edges in one patient. Magnetic resonance images showed normal bone marrow or bone sclerosis in the odontoid process. Soft tissue edema was absent. A bone scan was not useful in resolving this issue. CONCLUSION: Computed tomography and magnetic resonance imaging can be useful in determining the chronicity of an odontoid fracture.

Aged↗
PubMed2005

Odontoid compression of the brainstem without basilar impression-- "odontoid invagination".

We report five patients with odontoid invagination, in which the odontoid process bulges upward into the foramen magnum and compresses the brainstem without deformity of the occipital bone. Two patients had a craniovertebral abnormality associated with Chiari malformation without instability of the craniovertebral junction (stable odontoid invagination). The other three patients had dislocation of the craniovertebral junction due to iatrogenic destruction of the occipital condyle, rheumatoid arthritis or an anomaly of C2 (unstable odontoid invagination). Patients with stable odontoid invagination underwent a transoral odontoidectomy followed by occipitocervical fixation. Those with unstable odontoid invagination underwent cervical traction followed by posterior fixation in reducible cases, while in irreducible cases odontoidectomy with subsequent occipitocervical fixation was performed. Decompression of the neuraxis together with symptomatic improvement was achieved in all patients and none became unstable or developed new symptoms during follow-up ranging from 3 to 15 years.

Adult↗
PubMed1989

Odontoid hypoplasia with vertebral cervical subluxation and ventriculomegaly in metatropic dysplasia.

Our experience with 12 patients with metatropic dysplasia has demonstrated two important and treatable complications: odontoid hypoplasia with subluxation of the first and second cervical vertebrae, and ventriculomegaly. Hypoplasia and lack of ossification of the odontoid process were noted in all cases. Subluxation of these two vertebrae was demonstrated in all six patients who had lateral flexion-extension radiographs; three had subluxation even in a neutral position, and sudden odontoid dislocation developed in another after a simple fall. Four individuals have had surgical fusion of the cervical vertebrae; one child died suddenly, 1 week before scheduled surgery. In the three patients in whom computed tomography scans of the head were obtained, enlarged ventricles were found; one had symptomatic increased intracranial pressure and required a shunt. We recommend that odontoid hypoplasia be evaluated in all patients with metatropic dysplasia. If subluxation is proved, atlantoaxial fusion should be performed before damage to the cervical part of the spinal cord results. Serial head circumference measurements and evaluation for hydrocephalus are also recommended.

Adolescent↗
PubMed1989

Traumatic central cord syndrome in a patient with Os odontoideum.

We report the case of a 33-year-old man who presented to the emergency department the morning after a motor vehicle accident with physical findings consistent with central cord syndrome. Radiographs of the cervical spine revealed os odontoideum. This abnormality of the odontoid process has not previously been described in association with central cord syndrome.

Adult↗
PubMed1996

Nonoperative management of Types II and III odontoid fractures: the Philadelphia collar versus the halo vest.

The nonoperative management of patients with Types II and III fractures of the odontoid process consists of a prolonged course of cervical immobilization. The need for rigid fixation, demonstrated by the routine use of the halo vest in many institutions, has never been rigorously substantiated. We retrospectively analyzed our results with the nonsurgical management of odontoid fractures to ascertain whether cranial fixation affected overall outcome. Fifty-four patients managed at the University of Virginia Health Sciences Center, Charlottesville, VA, between 1976 and 1994 were studied. All 18 patients with Type III fractures (5 treated in the collar, 18 in the halo vest) demonstrated fracture healing and late stability. Among 36 individuals with Type II fractures, 20 were treated in the halo vest and 16 were managed in the Philadelphia collar or similar orthoses. The overall rate of late surgical intervention, the stability to flexion and extension, and the rate of bony fracture healing were not statistically different between the methods of immobilization. The rate of bony union was not significantly higher in the halo vest group (74 versus 53%), even though patients managed in the Philadelphia collar were significantly older than those in the halo vest (mean, 68 versus 44 yr). In general, nonsurgical management of Type III odontoid fractures was recommended, accompanied by use of a cervical orthosis. The determination of operative versus nonoperative treatment for Type II fractures was made on the basis of fracture anatomy, patient age, other associated injuries, and patient preference. The lack of a significant difference in the need for late surgical procedures or late instability, improved patient comfort with the cervical orthosis, and elimination of the risk of halo-related complications favored the use of the rigid cervical orthosis in the majority of these cases.

Aged↗
PubMed1994

Transverse atlantal ligament disruption associated with odontoid fractures.

OBJECTIVES: The authors evaluated transverse atlantal ligament integrity in patients with fractures of the odontoid process of the axis. SUMMARY OF BACKGROUND DATA: Injuries of the transverse atlantal ligament can result in atlantoaxial instability after fractures of the atlas or axis, even if osseous healing occurs. METHODS: The clinical histories and follow-up examinations and radiographic data of 30 patients with odontoid fractures were reviewed, using a combination of magnetic resonance (MR) imaging, thin-cut computed tomography (CT), and plain radiographs to evaluate osseous and ligamentous injuries. RESULTS AND CONCLUSIONS: Osteoperiosteal ligamentous avulsion injuries were identified on MR imaging in three patients and were associated with acute and delayed instability and nonunion. The combination of MR imaging, CT, and plain radiographs is useful in evaluating unstable odontoid fractures to facilitate rational treatment planning. Odontoid fractures with transverse ligament injuries should be considered for early surgical stabilization because this combination of injuries is unlikely to heal nonoperatively. Anterior odontoid screw fixation should be avoided when the ligament is injured.

Adolescent↗
PubMed2002

Dolichoodontoid in a pediatric patient.

Dolichoodontoid is defined as hypertrophy of the apical portion of the odontoid process of the axis. We report the first case of a dolichoodontoid process in a pediatric patient with other congenital anomalies. This rare entity has had three previous citations in the literature. Our patient presented with scoliosis in which subsequent MRI demonstrated a Chiari I malformation, a small thoracic syrinx and a dolichoodontoid process. The diagnosis of this malformation should be entertained in cases of craniocervical anomalies.

Arnold-Chiari Malformation↗
PubMed2002

Median (third) occipital condyle.

Abnormalities of the craniovertebral junction, most of which are associated with the occipital bone, are of interest not only to anatomists but also to clinicians because many of these deformities produce clinical symptoms. The occipital bone in humans is formed by the fusion of the sclerotomes corresponding to the roots of the hypoglossal nerve. In lower vertebrates, the cranial half of the first cervical sclerotome forms a separate bone between the atlas and occipital bone, the proatlas; in man it may contribute to anomalous structures around the foramen magnum. One such structure, a median occipital condyle, which exhibited an articular facet for the odontoid process, was observed in an adult male skull at the anterior margin of the foramen magnum. This anomaly is discussed in light of available literature.

Adult↗
PubMed1991

Internal fixation of the odontoid: a newer approach to an old problem.

A surgical approach to cervical spine instability associated with odontoid fracture is described. Internal fixation of the odontoid (IFO) has advantages over traditional posterior surgical treatments currently employed. This approach to the odontoid process is easier for the surgeon comfortable with anterior discectomy to perform than other techniques described in the spine literature.

Adolescent↗
PubMed2004

[Transarticular fixation of C1-C2: a multicenter retrospective study].

PURPOSE OF THE STUDY: Transarticular C1-2 fixation is a surgical alternative in treatment of atlantoaxial instability. Although the method provides very good immediate and long-term stability, it still involves several disadvantages. The group of patients as reported from various institutions are usually very small and hardly comparable. In order to objectively compare the results of the method, we collected the groups of patients treated in four institutions dealing with surgery of the cervical spine in Czech Republic. MATERIAL AND METHODS: During the 9-years period (1993-2001), the transarticular C1/2 fixation was performed in 80 patients (mean age 45.6 years, range 4-85 years). The procedure was indicated for atlantoaxial instability due to rheumatoid arthritis in 32 cases, pseudoarthrosis of the odontoid process in 15 cases, fracture of the odontoid in 8 cases, complex C1-C2 fracture in 7 cases, tumour in 5 cases, C1 fracture in 4 cases, os odontoideum in 3 cases, purulent osteolysis of the odontoid in 3 cases and instability due to tuberculosis in one case, respectively. Two patients underwent surgery for painful arthrosis of atlantoaxial joints only. Transarticular fusion was combined with posterior interlaminar fixation using autologous graft and wire in most of the cases. Clinical and radiological results were evaluated in the early postoperative period and 3, 6 and 12 months after surgery, respectively. The position of the screws in relation to lateral mass of the atlas was evaluated according to our own criteria as optimal, suboptimal, and misplaced. Long-term postoperative stability and bone fusion were also followed. The follow-up ranged from 3 to 99 months (mean 29.1 months). There were 72 patients available for long-term follow-up (i.e. more then 6 months). RESULTS: We inserted 150 screws; two screws were used in 72 patients, one screw in 6 patients while in two patients, the surgery had to be aborted without screwing. Optimal placement was achieved in 103 cases (68.7%), suboptimal because of too medial or lateral placement of the screws in 26 cases (17.3%), suboptimal due to a short screw in 9 case (6%) and a long screw in 8 cases (5.3%). Four screws (2.7%) were found misplaced (i.e. out of the lateral masses). Fusion was confirmed in 51 cases out of 72 operated on (70.8%) at 6-months follow-up, and in 55 cases out of 63 available for follow-up (87.3%) at 12 months, respectively. Segmental stability was achieved in all patients, even in cases with incomplete fusion as seen on radiograph. Furthermore, six screws in four patients were discovered to be broken, nevertheless without any clinical consequences. There were 4 cases of peroperative injury to th vertebral artery (i.e. 5% of patients, 2.7% of screws), one case of dural tear and one case of excessive blood loss from epidural venous plexus. These complications, however, did not cause any significant clinical consequences, either. Other postoperative complications included wound dehiscence in 3 cases, 2 cases of hardware failure due to wrong indication for surgery and 2 cases of persistent neck pain. DISCUSSION: Transarticular C1/2 fixation is known to be universal and stable technique suitable for the treatment of atlantoaxial instability. According to biomechanical studies, this method provides the best stability mainly in rotation and lateral flexion (inclination) when compared to other described methods of atlantoaxial fixation. The fusion rate is reported to vary between 90 to 100% if the posterior interlaminar fusion using bone graft and wire is simultaneously performed. The rare incidence of pseudarthrosis is usually considered to be related to a poor surgical technique as even only one screw should provide bone fusion if properly placed. Using strict evaluation criteria, the fusion rate in our sample of patients was 87.3% at 12 months, or, 92.1% if also controversial radiographs were included. The injury to the vertebral artery is the most serious complication of the method; its incidence in our group (5% of patients) is comparable to data from literature. We believe that most of these events happened because of individual anatomical variations of axis and vertebral artery were not adequately respected. CONCLUSION: Transarticular technique of instrumental atlantoaxial fusion is an effective method with multiple application in treatment of craniocervical and upper cervical spine instability. The gain of immediate stability with acceptable risk of possible complications is the major advantage of this procedure. The results of our multicentric retrospective study confirm the expected high fusion rate and are comparable to previously published reports.

Adolescent↗
PubMed1994

Fractures of the C-2 vertebral body.

Vertical C-2 body fractures are presented in 15 patients with clinical and imaging correlations that suggest the existence of a variety of mechanisms of injury. In these patients, clinical and imaging correlations were derived by: 1) defining the point of impact by clinical examination; 2) defining the point of impact by soft-tissue changes on cranial magnetic resonance (MR) imaging or computerized tomography (CT); 3) obtaining an accurate history of the mechanism of injury; and 4) spine imaging (x-ray studies, CT, and MR imaging) of the C-2 body fracture and surrounding bone and soft tissue. The cases presented involve the region located between the dens and the pars interarticularis of the axis. Although these fractures are rarely reported, they are not uncommon. An elucidation of their pathological anatomy helps to further the understanding of the mechanistic etiology of upper cervical spine trauma. A spectrum of mechanisms of injury causing upper cervical spine fractures was observed. The type of injury incurred is determined predominantly by the force vector applied during impact and the intrinsic strength and anatomy of C-2 and its surrounding spinal elements. From this clinical experience, two types of vertical C-2 body fractures are defined and presented: coronally oriented (Type 1) and sagittally oriented (Type 2). A third type of C-2 body fracture, the horizontal rostral C-2 fracture (Type 3), is added for completeness; this Type 3 fracture is the previously described Type III odontoid process fracture described by Anderson and D'Alonzo.

Adult↗
PubMed2002

[Management of odontoid fractures using anterior screw fixation: analysis of 15 cases].

A retrospective analysis of the results of 15 patients with odontoid fractures type II P and II N, according to Roy-Camille's classification is presented. They were operated on by an anterior approach and direct fixation of the odontoid process through a screw. There were 13 men and 2 women, the age ranging from 14 to 74 years. The follow up period was from 6 to 36 months (mean 20 months). There was only one complication related to the surgical technique: one screw was misplaced and it was necessary another surgery to replace it. There were no deaths in this series. There were no screw breakdown and the fusion rate was 94%. We propose, based on this study, that the classification of Roy-Camille for odontoid fractures should be always used, since it proposes one surgical approach for each type of fracture. The results of this series show that this technique is useful and has advantages over another modalities of treatment. The correct diagnosis of the type of fracture and an appropriate selection of patients are the main elements to achieve good results.

Adolescent↗