Odontoid fracture of the second cervical vertebra (C2) is the most common spinal fracture type in elderly patients. However, very little is known about the biomechanical fracture mechanisms, but could play a role in fracture prevention and treatment. This study aimed to investigate the biomechanical competence and fracture characteristics of the odontoid process. A total of 42 human C2 specimens (14 female and 28 male, 71.5 ± 6.5 years) were scanned via quantitative computed tomography, divided in 6 groups (n = 7) and subjected to combined quasi-static loading at a rate of 0.1 mm/s until fracturing at inclinations of −15°, 0° and 15° in sagittal plane, and −50° and 0° in transverse plane. Bone mineral density (BMD), specimen height, fusion state of the ossification centers, stiffness, yield load, ultimate load, and fracture type according to Anderson and d'Alonzo were assessed. While the lowest values for stiffness, yield, and ultimate load were observed at load inclination of 15° in sagittal plane, no statistically significant differences could be observed among the six groups (p = 0.235, p = 0.646, and p = 0.505, respectively). Evaluating specimens with only clearly distinguishable fusion of the ossification centers (n = 26) reveled even less differences among the groups for all mechanical parameters. BMD was positively correlated with yield load (R² = 0.350, p < 0.001), and ultimate load (R² = 0.955, p < 0.001), but not with stiffness (p = 0.070). Type III was the most common fracture type (23.5%). These biomechanical outcomes indicate that load direction plays a subordinate role in traumatic fractures of the odontoid process in contrast to BMD which is a strong determinant of stiffness and strength. Thus, odontoid fractures appear to result from an interaction between load magnitude and bone quality

The purpose of this study was to propose a new classification based on the structural, anatomical and biomechanical properties of the odontoid process, to evaluate the outcome and to suggest the adequate treatment in relation to the specific fracture type. The files of 97 patients with odontoid process fractures admitted to our institution were reviewed. The external and internal anatomy of the axis has been studied. The fractures were classified according to the proposed new classification. The method was tested for reliability and validity. Mean follow-up was 14 years. Intraobserver and interobserver agreement was excellent with intraclass correlation coefficients at levels of 0.98 and 0.85 respectively. Four types of odontoid process fractures are distinguished; type A fractures are avulsion fractures involving the tip of the odontoid; type B fractures are fractures of the neck between the lower edge of the transverse ligament and the line connecting the medial corners of the upper articular facets of the axis; type C fractures involve the area between the previously mentioned line and the base of the odontoid process (type C1) or extend to the body of the axis (type C2); type D fractures are complex fractures involving more than one level of the odontoid process. Classification of odontoid process fractures has to be reconsidered as novel imaging technology has shown new patterns of fractures. Computed tomography scan with image reconstruction is mandatory. The analysis of the imaging data in the present study justifies the new classification

Between 1982 and 2000, 37 cases of fractures of the odontoid process were treated at Hirosaki University Hospital. There were 16 females and 21 males, with an average age of 43.9 and 37.7 respectively. Twenty-three of 37 were type II and 14 were type III by the classification of Anderson and D’Alonzo. Eight of type II were old fractures. Nineteen of them were injured in traffic accidents, 9 in accidental falls from a height, 4 by falling down, 2 in lumbering accidents and 3 by unknown causes. Severe neurological disorders were recognized in 7, mild in 12 and 22 had no neurological disorders. Neurological disorders were correlated with SAC (space available for spinal cord) at C1-2. Twenty-two of type II (95.7%) and 10 of type III (71%) were treated surgically. Surgical methods were anterior screw fixation of the odontoid process in 7, anterior atlanto-axial joint fixation in 3, posterior atlanto-axial joint fixation in 5, posterior occipito-cervical fusion in 3, anterior and posterior combined fixation of the atlanto-axial joint in 2 and others in 2. Bone union was obtained in 18 (81.8%) of type II and 10 (100%) of type III by the primary operations. There was no nonunion in anterior screw fixation cases. Nonunion occured in one of type II (100%) and 2 of type III (50%) treated nonoperatively. Two of them were operated for nonunion. One of them remained nonunion by two additional operations. No case of nonunion showed neurological deterioration for 91.8 months after treatment on average. Anterior direct screw fixation of the odontoid process is superior to the other methods in the point of immobilization of the odontoid fragment without limiting the motion of the atlanto-axial joint. We recommend anterior direct screw fixation of the odontoid process as a first choice of the surgical method for fresh fractures of the odontoid process in cases with reduced fragments

Aims. Fracture of the odontoid process (OP) in the elderly is associated with mortality rates similar to those of hip fracture. The aim of this study was to identify variables that predict mortality in patients with a fracture of the OP, and to assess whether established hip fracture scoring systems such as the Nottingham Hip Fracture Score (NHFS) or Sernbo Score might also be used as predictors of mortality in these patients. Patients and Methods. We conducted a retrospective review of patients aged 65 and over with an acute fracture of the OP from two hospitals. Data collected included demographics, medical history, residence, mobility status, admission blood tests, abbreviated mental test score, presence of other injuries, and head injury. All patients were treated in a semi-rigid cervical orthosis. Univariate and multivariate analysis were undertaken to identify predictors of mortality at 30 days and one year. A total of 82 patients were identified. There were 32 men and 50 women with a mean age of 83.7 years (67 to 100). Results. Overall mortality was 14.6% at 30 days and 34.1% at one year. Univariate analysis revealed head injury and the NHFS to be significant predictors of mortality at 30 days and one year. Multivariate analysis showed that head injury is an independent predictor of mortality at 30 days and at one year. The NHFS was an independent predictor of mortality at one year. The presence of other spinal injuries was an independent predictor at 30 days. Following survival analysis, an NHFS score greater than 5 stratified patients into a significantly higher risk group at both 30 days and one year. Conclusion. The NHFS may be used to identify high-risk patients with a fracture of the OP. Head injury increases the risk of mortality in patients with a fracture of the OP. This may help to guide multidisciplinary management and to inform patients. This paper provides evidence to suggest that frailty rather than age alone may be important as a predictor of mortality in elderly patients with a fracture of the odontoid process. Cite this article: Bone Joint J 2019;101-B:253–259

We treated 183 patients with fractures of the odontoid process (109 type II, 74 type III) non-operatively. Union was achieved in 59 (54%) with type-II fractures. All type-III fractures united, but in 16 patients union was delayed. There was no correlation between union and the clinical or radiological outcome of the fractures. Selective vertebral angiography, carried out in 18 patients ten with acute fractures and eight with nonunion, showed that the blood supply to the odontoid process was not disrupted. Studies on ten adult axis vertebrae at post-mortem showed that the difference in the surface area between type-II and type-III fractures was statistically significant. Our findings show that an age of more than 40 years, anterior displacement of more than 4 mm, posterior displacement and late presentation contribute towards nonunion of type-II fractures

In type-II fractures of the odontoid process, the treatment is either conservative in a halo vest or primary surgical stabilisation. Since nonunion, requiring prolonged immobilisation or late surgery, is common in patients treated in a halo vest, the identification of those in whom this treatment is likely to fail is important. We reviewed the data of 69 patients with acute type-II fractures of the odontoid process treated in a halo vest. The mean follow-up was 12 months. Conservative treatment was successful, resulting in bony union in 32 (46%) patients. Anterior dislocation, gender and age were unrelated to nonunion. However, nonunion did correlate with a fracture gap (> 1 mm), posterior displacement (> 5 mm), delayed start of treatment (> 4 days) and posterior redisplacement (> 2 mm). We conclude that patients presenting with these risk factors are unlikely to achieve bony union by treatment in a halo vest. They deserve careful attention during the follow-up period and should also be considered as candidates for primary surgical stabilisation

Aims: The optimal treatment of Type II odontoid fractures remains controversial. Our retrospective multicentric study of 114 odontoid process fractures documents experience with management of these fractures and discuss a new classification subtype II T and its surgical treatment. Methods: Fractures were defined using plain radiographs and CT reconstructions as per the Anderson- D’Alonzo classification. We have surgically treated 114 consecutive patients suffering from C2 odontoid fracture. 104 fractures were classified as Type II and 10 as Type III. Two cases of atypical, horizontal, mid-shaft odontoid process fractures were reported. In 55% an anterior two-screw fixation technique was chosen, remaining 45% underwent single-screw fixation. Results: One year follow-up data were available in 86.8% of cases and no major complications were found. Fusion rate calculated 6 months following surgery was 93%. We encountered cases, where the fracture line passes transversally through the middle of the shaft of odontoid process, below the level of transverse atlantal ligament, and we suggest to classify these cases as Type II T fractures. Also we analysed series of 75 surgically treated C1-2 instabilities and out of 11 pseudoarthrosis of the odontoid process 7 unrecognised Type II T fractures were found. Conclusions: Reported atypical fractures, newly classified as Type II T, are highly unstable (especially in rotations). In the authors’ opinion, two- screw technique should be the treatment of choice when internal fixation indicated

A four-year-old boy presented with a solitary bone cyst in the odontoid process and body of the axis. Plain radiographs showed a radiolucent lesion with extreme thinning of the cortex and MRI demonstrated a high signal intensity in the interlesional matrix. The cystic component extended into the body of the axis through a defect in the epiphyseal plate. At operation, the cavity of the cyst was found to contain serosanguineous fluid, and histological examination showed that it was lined by a thin layer of connective tissue. The cyst may have originated from a defect in the epiphyseal plate

1. Fifty-one cases of fracture of the odontoid have been analysed. Forty were reported by other surgeons; eleven were new cases first reported by us.

2. Fracture of the odontoid in young children is an epiphysial separation. It occurs up to the age of seven years. As in epiphysial separations elsewhere, it unites readily, and remodelling occurs when reduction has been incomplete, so that normal anatomy is restored.

3. In adults forward displacement is twice as common as backward displacement.

4. Immediate paralysis is commoner if backward displacement occurs, but late neurological disorders are seen only after fractures with forward displacement.

5. Failure of bony healing is not dangerous if treatment has resulted in firm fibrous union, for there is neither excessive abnormal mobility nor progressive subluxation, either of which could injure the spinal cord or medulla. Neurological disorders developing after the fracture are the result of mobility from inadequate early treatment. It is the results of inadequate early treatment which have given this fracture a sinister reputation.

6. The fracture should be reduced by skeletal traction through a skull caliper. The reduction should be maintained for six weeks by continuous traction, and this should be followed by a period of six weeks in a plaster.

7. The increasing definition of the fracture-line seen in the radiographs of some patients indicates non-union.

High definition computed cervical myelograms have been made in flexion and extension in 13 patients with Morquio-Brailsford's disease. We observed that: 1) odontoid dysplasia was present in every case, with a hypoplastic dens and a detached distal portion which was not always ossified; 2) atlanto-axial instability was mild, and anterior atlanto-axial subluxation was absent in most cases; 3) severe spinal cord compression, when present, was due to anterior extradural soft-tissue thickening; 4) this compression was not relieved by flexing or extending the neck and was manifested early in life; 5) posterior occipitocervical fusion resulted in disappearance of the soft-tissue thickening and normalisation of subsequent development of the dens. We conclude that the severity of neurological involvement at the craniovertebral junction was determined by soft-tissue changes, not by the type of odontoid dysplasia nor by subluxation. Posterior occipitocervical fusion proved to be an effective treatment.

Fractures of the odontoid peg are common spinal injuries in the elderly. This study compares the survivorship of a cohort of elderly patients with an isolated fracture of the odontoid peg versus that of patients who have sustained a fracture of the hip or wrist. A six-year retrospective analysis was performed on all patients aged > 65 years who were admitted to our spinal unit with an isolated fracture of the odontoid peg. A Kaplan–Meier table was used to analyse survivorship from the date of fracture, which was compared with the survivorship of similar age-matched cohorts of 702 consecutive patients with a fracture of the hip and 221 consecutive patients with a fracture of the wrist.

A total of 32 patients with an isolated odontoid fracture were identified. The rate of mortality was 37.5% (n = 12) at one year. The period of greatest mortality was within the first 12 weeks. Time made a lesser contribution from then to one year, and there was no impact of time on the rate of mortality thereafter. The rate of mortality at one year was 41.2% for male patients (7 of 17) compared with 33.3% for females (5 of 15).

The rate of mortality at one year was 32% (225 of 702) for patients with a fracture of the hip and 4% (9 of 221) for those with a fracture of the wrist. There was no statistically significant difference in the rate of mortality following a hip fracture and an odontoid peg fracture (p = 0.95). However, the survivorship of the wrist fracture group was much better than that of the odontoid peg fracture group (p < 0.001). Thus, a fracture of the odontoid peg in the elderly is not a benign injury and is associated with a high rate of mortality, especially in the first three months after the injury.

Cite this article: Bone Joint J 2014;96-B:88–93.

Background: Type II odontoid fractures are the commonest upper cervical spine injury in the elderly, following minor falls. Structural heterogeneity within the axis with deficiency of bone mass in the base of the odontoid process has been attributed for these fractures. Aims: To analyse whether osteoporosis at the dens-body junction is directly related to the occurrence of odontoid fractures in the elderly. Material and Methods: We studied the reformatted CT scan images of 36 patients over the age of 70 years who had cervical spine injuries following minor trauma. In all these patients the severity of osteoporosis at the dens-body junction, and in the peg and body of axis were evaluated. The osteoporosis was graded into none, mild, moderate and severe. Statistical analysis was performed using Pearson’s Chi-square test to find the significance of osteoporosis at the dens-body junction in producing Type II odontoid fractures in the elderly. Results: Type II odontoid fractures was seen in 21 patients. Eleven of the 21 patients with Type II fractures and eight of the 15 patients with no Type II odontoid fractures had significant osteoporosis at the dens-body junction. Five patients with Type II fracture and eight patients with no Type II fractures had significant osteoporosis at the dens and body of axis. Statistical analysis showed that the osteoporosis at the dens-body junction was not significant in patients with Type II odontoid fracture compared to those with no Type II odontoid fracture (χ. 2. = 1.1; df = 3, p = 0.78). Conclusions: Eventhough osteoporosis is one of the factors that increase the incidence of Type II fractures of the odontoid process in the elderly, it is not a direct aetiological factor

Background: Type II odontoid fractures are the commonest upper cervical spine injury in the elderly, following minor falls. Structural heterogeneity within the axis with deficiency of bone mass in the base of the odontoid process has been attributed for these fractures. Aims: To analyse whether osteoporosis at the dens-body junction is directly related to the occurrence of odontoid fractures in the elderly. Material and Methods: We studied the reformatted CT scan images of 36 patients over the age of 70 years who had cervical spine injuries following minor trauma. In all these patients the severity of osteoporosis at the dens-body junction, and in the peg and body of axis were evaluated. The severity was graded into none, mild, moderate and severe, depending on the cortical thickness, trabecular pattern, and the size of holes (absence of trabeculae) using sagittal, coronal and transverse sections of CT scan pictures. The osteoporosis was graded into none, mild, moderate and severe. Statistical analysis was performed using Pearsons Chi-square test to find the significance of osteoporosis at the dens-body junction in producing Type II odontoid fractures in the elderly. Results: Type II odontoid fractures was seen in 21 patients. Eleven of the 21 patients with Type II fractures and eight of the 15 patients with no Type II odontoid fractures had significant osteoporosis at the dens-body junction. Five patients with Type II fracture and eight patients with no Type II fractures had significant osteoporosis at the dens and body of axis. Statistical analysis showed that the osteoporosis at the dens-body junction was not significant in patients with Type II odontoid fracture compared to those with no Type II odontoid fracture (Chi-square value = 1.1; df = 3, p = 0.78). Conclusions: Eventhough osteoporosis is one of the factors that increase the incidence of Type II fractures of the odontoid process in the elderly, it is not a direct aetiological factor

Purpose of the study: Cases of serious trauma to the cervical spine requiring surgical management in older subjects goes in hand with the general trend towards a more active elderly population. We analyzed retrospectively our experience with 28 patients cared for in our unit from 1990 to 1999. Patients and methods: Mean age of these 11 women and 17 men was 73 years (range 65–93). High-energy trauma was the cause of the cervical injury in 12 patients (42%). The others were victims of falls in their homes. This later cause explains the long delay to care (21 days on the average with a range from zero days to six months). The six patients who had injuries to the upper cervical spine had fractures of the odontoid process secondary to a fall. The mobile segment of the spine was involved in most of the injuries involving the lower cervical spine (eleven severe sprains and six dislocations) resulting from high-energy trauma in half of the cases. These injuries occurred above an osteoarthritic block. Half of the patients had neurological complications: eleven immediate, three late. The Franckel classification was: A=2, C=4, D=7. The same repair technique was used for the upper an lower cervical spine. Five of the six fractures of the odontoid process were fixed with a Bölher screw, and one with posterior fusion. An anterior graft with plate fixation was used 18 times for the lower spine. Roy Camille posterior fixation was used four times because of the irreducible nature of the fracture or because of the need for posterior fusion. Results: Morbidity was high. Seven patients (25%) had serious cardiorespiratory complications leading to death in five patients. All these patients had neurological sequelae (Franckel A and C). For the other patients, the postoperative period was uneventful and similar to that observed in younger patients (immobilization, neurological recovery, consolidation). Discussion: The high frequency of upper cervical spine trauma observed in our series is also reported in the literature. It increases with age. The frequency of neurological involvement was identical to that observed by Roth and Spivak. Prognosis was poor in case of neurological involvement. The appropriateness of surgery in Franckel A patients may be questionable. Surgery cannot avoid the risk of mortality in these patients but it can enable mobilisation and nursing care, avoiding the need for a halo jacket. Conclusion: Spinal trauma in the elderly can be managed similarly to that in young adults, at least in cases without major neurological involvement

We report three patients in whom a fractured odontoid process was associated with a fracture of the superior articular process of the second cervical vertebra. Although there were no signs of neurological disorder, damage to the C1-C2 joint in all three patients made fusion necessary. Forced lateral flexion is suggested as the possible mechanism of injury

Twenty-three adults with fractures of the odontoid process are reviewed. Te possible reasons for the high rate of non-union in reported series are considered: these include the type of fracture, its displacement, the presence of a gap at the fracture site, imperfect reduction and inadequate immobilisation. Type 2 fractures (at the base of the odontoid process) are the commonest and also the most liable to nonunion. In their treatment, reduction is important; as seen in the lateral radiograph at least two-thirds of the fracture surfaces should be in contact. Skull traction is not advised and halo-cast fixation is the treatment of choice; with this method 87.5 per cent of recent odontoid fractures united

We have reviewed 81 patients with fractures of the odontoid process treated between May 1983 and July 1997, by anterior screw fixation. There were 29 patients with Anderson and D’Alonzo type-II fractures and 52 with type III. Roy-Camille’s classification identified the direction and instability of the fracture. Operative fixation was carried out on 48 men and 33 women with a mean age of 57 years. Associated injuries of the cervical spine were present in 15 patients, neurological signs in 13, and 18 had an Injury Severity Score of more than 15. Nine patients died and 11 were lost to follow-up. Of 61 patients, 56 (92%) achieved bony union at an average of 14.1 weeks. Two patients required a secondary posterior fusion after failure of the index operation. A full range of movement was restored in 43 patients; only six had a limitation of movement greater than 25%. We conclude that anterior screw fixation is effective and practicable in the treatment of fractures of the dens

1. Injuries to the atlas and axis may occur at any age. They are usually not fatal. 2. In children spontaneous rotatory dislocation is the commonest type of lesion. In adults fracture of the odontoid process is more likely. 3. The spinal cord is often undamaged. In some cases complicated by cord damage the neurological disturbance is caused by an associated injury to the lower cervical spine. 4. Spinal cord damage may be immediate or delayed. 5. In cases of incomplete cord lesion there may be recovery of function after reduction of the displacement or without such reduction. 6. Diagnosis rests on the history and physical signs, and radiographic findings. Radiographs of this area require careful interpretation, and special radiographic techniques may he necessary. A normal radiograph does not necessarily exclude the possibility of atlanto-axial injury. 7. Though many patients would survive without treatment the initial discomfort and danger of complications demand that adequate protection be provided. In relatively minor injuries and in old people protection by a plaster collar may be sufficient. In some cases it is justifiable to undertake manipulation and apply a plaster. Cases with severe displacement require traction, preferably by skull calipers. Recurrent displacement, instability, and cord signs demand operative reduction and fusion. Satisfactory fusion of the atlas and axis alone is feasible, and good function is preserved. More extensive fusion of the cervical spine is seldom necessary

Introduction and Aims: Odontoid fractures are quite common in the elderly following minor falls. As there are a few articulations in the upper cervical spine, degeneration in any one particular joint may affect the biomechanics of loading of the upper cervical spine. We aimed to analyse the pattern and relationship of odontoid fractures to the upper cervical spine osteoarthritis in the elderly. Method: Between July 1999 and March 2003, 185 patients had CT scan of the cervical spine for cervical spine injuries. Twenty-three out of 47 patients over the age of 70 years had odontoid fractures. The CT scan pictures of these patients were studied to analyse the type of fracture and its displacement, the severity of osteoarthritis in each articulation in the upper cervical spine, namely lateral atlantoaxial, atlantooccipital, atlantoodontoid and subaxial facetal joints, evaluation of osteopenia in the dens-body junction and in the body and odontoid process of the axis, and calcification of the ligaments. Results: Twenty-one of the 23 patients had Type II odontoid fracture with posterior displacement in seven (33.3%) and posterior angulation in nine (42.8%) patients. In these patients with Type II dens fracture, the atlantodens interval was obliterated in 19 (90.48%) patients, with only two of them (9.52%) having lateral atlantoaxial osteoarthritis. Conclusion: Type II fracture is the commonest odontoid fracture in the elderly. Posterior displacement of the fracture is common in elderly, unlike the younger population. There is a significant relationship between the upper cervical spine osteoarthritis, apart from osteopenia, to the incidence of Type II odontoid fractures. Significant atlantoodontoid osteoarthritis in the presence of normal lateral atlantoaxial joints increases the risk of sustaining Type II odontoid fracture