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

Biomechanics of halo-vest and dens screw fixation for type II odontoid fracture

STUDY DESIGN

An in vitro biomechanical study of halo-vest and odontoid screw fixation of Type II dens fracture.

OBJECTIVE

The objective were to determine upper cervical spine instability due to simulated dens fracture and investigate stability provided by the halo-vest and odontoid screw, applied individually and combined.

SUMMARY OF BACKGROUND DATA

Previous studies have evaluated posterior fixation techniques for stabilizing dens fracture. No previous biomechanical study has investigated the halo-vest and odontoid screw for stabilizing dens fracture.

METHODS

A biofidelic skull-neck-thorax model was used with 5 osteoligamentous whole cervical spine specimens. Three-dimensional flexibility tests were performed on the specimens while intact, following simulated dens fracture, and following application of the halo-vest alone, odontoid screw alone, and halo-vest and screw combined. Average total neutral zone and total ranges of motion at C0/1 and C1/2 were computed for each experimental condition and statistically compared with physiologic motion limits, obtained from the intact flexibility test. Significance was set at P < 0.05 with a trend toward significance at P < 0.1.

RESULTS

Type II dens fracture caused trends toward increased sagittal neutral zone and lateral bending range of motion at C1/2. Spinal motions with the dens screw alone could not be differentiated from physiologic limits. Significant reductions in motion were observed at C0/1 and C1/2 in flexion-extension and axial rotation due to the halo-vest, applied individually or combined with the dens screw. At C1/2, the halo-vest combined with the dens screw generally allowed the smallest average percentages of intact motion: 3% in axial rotation, 17% in flexion-extension, and 18% in lateral bending.

CONCLUSION

The present reduction in C1/2 motion observed, due to the halo-vest and dens screw combined is similar to previously reported immobilization provided by the polyaxial screw/rod system and transarticular screw fixation combined with wiring. The present biomechanical data may be useful to clinicians when choosing an appropriate treatment for those with Type II dens fracture.

Treatment of remote type ii axis fractures in the elderly: feasibility of anterior odontoid screw fixation

OBJECTIVE

This preliminary study considers the feasibility and the results of anterior screw fixation in elderly patients with remote Type II axis fractures. Odontoid fractures are the most common fractures of the cervical spine in people 70 years of age or older. In developing countries, direct anterior fracture fixation is replacing posterior fusion in many cases. Recently, it has been demonstrated that patient age does not influence the outcome in terms of fusion after odontoid screw fixation. There is considerable disagreement about correct treatment in the case of remote fractures. In the literature, there have been no studies considering the feasibility and results of anterior screw fixation in elderly patients with remote Type II axis fractures.

METHODS

From 1989 to 2005, we observed 9 patients over the age of 65 years with isolated Type II remote fractures of the dens. All fractures were considered to be inveterate, as the traumatic events had occurred 6 to 12 months earlier. All fractures were treated with anterior infibulation of the dens with single 3.5-mm cannulated screws.

RESULTS

A bony fusion was radiologically documented in 7 patients (77%) 4 to 16 months after the intervention. In 1 patient, a fibrous union was observed. The neurological status remained unchanged in all patients, and no patients showed any neurological impairment at the time of follow-up.

CONCLUSION

According to our preliminary study, the technique appears to be feasible for remote axis fractures within 12 months of trauma, and it seems to be safe for elderly patients. Further data from additional studies are needed.

Nonoperative management of type II odontoid fractures in the elderly

STUDY DESIGN

Retrospective case series of elderly patients with Type II odontoid fractures, with prospective functional follow-up.

OBJECTIVE

We aimed to investigate the functional outcomes after nonoperative management of Type II odontoid fractures in elderly patients at a Level 1 trauma center.

SUMMARY OF BACKGROUND DATA

Controversy exists regarding the most appropriate method of treatment of Type II odontoid fractures in the elderly population. The primary aim of management has generally been considered to be the achievement of osseous fusion.

METHODS

Patients >or=65 years of age presenting to a Level 1 trauma center with Type II odontoid fractures were identified retrospectively from a prospective neurosurgery database. Those initially treated operatively, or who died before follow-up were excluded. Long-term pain and functional outcomes were assessed.

RESULTS

Forty-two patients were followed up at a median of 24 months post injury. Ten patients (24%) were treated in cervical collars alone and 32 patients (76%) were managed in halothoracic braces. Radiographically demonstrated osseous fusion occurred in 50% of patients treated in collars and in 37.5% of patients managed in halothoracic bracing. However, fracture stability was achieved in 90% and 100% of cases respectively. In patients treated in collars, 1 patient had severe residual neck pain, severe disability, and poor functional outcome. There were no cases of severe pain or disability, or poor functional outcome in patients managed in halothoracic orthoses. There was no difference in outcome in those achieving osseous union compared with stable fibrous union.

CONCLUSION

The nonoperative management of Type II odontoid fractures in elderly patients results in fracture stability, by either osseous union or fibrous union in almost all patients. Long-term clinical and functional outcomes seem to be more favorable when fractures have been treated with halothoracic bracing in preference to cervical collars. Stable fibrous union may be an adequate aim of management in elderly patients.

Early predictive value of supine and upright X-ray films of odontoid fractures treated with halo-vest immobilization

BACKGROUND

Although halo-vest immobilization remains a common form of treatment for type II odontoid fractures, nonunion and C1-2 instability may be the result in up to 20% to 40% of patients.

PURPOSE

Supine and upright lateral X-ray films may allow early identification of patients likely to fail halo-vest treatment and earlier surgical treatment with decreased morbidity from prolonged unsuccessful halo-vest immobilization.

STUDY DESIGN/SETTING

A prospective cohort study was performed.

PATIENT SAMPLE

Twenty patients with type II odontoid fractures.

OUTCOME MEASURES

Posttreatment nonunion and C1-2 instability as determined by plain X-ray films and computed tomography scan.

METHODS

Both supine and upright lateral X-ray films were obtained immediately after halo-vest application and at the 2-week, 6-week, and 3-month follow-up. Flexion-extension lateral X-ray films were obtained after halo-vest removal. Patients with nonunion or instability underwent computed tomography scan. Upright X-ray films were compared serially to identify loss of reduction. Pairs of supine and upright X-ray films were compared to measure any change in displacement or angulation upon transition from supine to upright position. Nonunion patients were compared with healed patients to determine any difference in fracture behavior based on serial supine and upright X-ray films.

RESULTS

Twenty patients with type II odontoid fractures were identified during the study period. Three patients with multiple trauma underwent immediate surgical stabilization. Three elderly patients with nondisplaced fractures were treated in a cervical orthosis. Fourteen patients initiated and completed 3 months of halo-vest immobilization. After halo-vest removal, 4 of 14 patients (29%) showed radiographic nonunion or instability. In all 4 nonunion patients, supine and upright radiographs at 2 weeks revealed change in fracture angulation > or =5 degrees between the supine and upright positions. In three of these patients standard serial upright lateral X-ray films failed to identify any loss of reduction. In the remaining patient, progressive angulation of 15 degrees was observed. No measurable change in angulation between supine and upright X-ray films was observed in any patient who healed successfully with halo-vest treatment.

CONCLUSIONS

Obtaining both supine and upright lateral X-ray films during the follow-up period may identify patients at risk for failure of halo-vest treatment as early as 2 weeks after initiation of treatment. A change in fracture angulation > or =5 degrees suggests an increased risk of treatment failure and the potential benefit of early surgical stabilization.

Nonoperative management of odontoid fractures using a halothoracic vest

OBJECTIVE

Despite various reports in the literature, the appropriate treatment of Type II odontoid fractures remains controversial. Although there is an increasing tendency toward surgical treatment of these fractures in recent years, nonoperative treatment strategies are still regarded as a practicable method, particularly in elderly patients with significant comorbidities. One purpose of this study was to determine the functional and radiographic long-term results after rigid immobilization of Type II odontoid fractures using a halothoracic vest. The second aim was to present a case-control series of patients with nonunion of Type II odontoid fractures compared with patients with successful fracture healing to determine specific risk factors for failure of halo immobilization.

METHODS

We reviewed the clinical and radiographic records of 90 patients with an average age of 69 years at the time of injury who had undergone nonoperative treatment of odontoid fractures using a halothoracic vest between 1988 and 2004. To identify potential risk factors for failure of halo fixation, patients were divided into "cases" and "controls." Cases were defined as patients with nonfusion after halo immobilization, and controls were patients with successful fracture healing attained with this treatment option.

RESULTS

Seventy-five patients returned to their preinjury activity level and were satisfied with their treatment. The Smiley-Webster scale showed an overall functional outcome score of 1.64. Successful fracture healing was achieved in 76 patients (84%). In 14 patients, nonunion was diagnosed by standard x-rays and additional computed tomographic scans within 6 to 12 months after trauma. Referring to possible risk factors for failure of halo fixation, nonunion was found significantly more often in older patients and in those with displaced fractures of the odontoid. Secondary loss of reduction and delay of treatment were identified as further risk factors for nonfusion.

CONCLUSION

With regard to successful fracture healing and functional results of the patients, we had a satisfactory outcome after halo fixation of Type II odontoid fractures. Although a fusion rate of 84% should not be deemed as optimal, nonoperative management of these fractures using a halothoracic vest seems to be an appropriate treatment strategy in patients who are not suitable for surgical treatment.

Die subdentale Synchondrose

BACKGROUND

During development of the axis, four different ossification centers are formed. The two cranial ossification centers are demarcated from the ossification center of the vertebral corpus by a subdental synchondrosis. During further development the subdental synchondrosis--which is thought to close spontaneously--might not close completely, which leads to the necessity for differentiating synchondrotic remnants from a fracture at the base of the dens (type II according to Anderson and D'Alonzo).

RESULTS

To characterize the architecture of the axis with particular attention to the subdental synchondrosis, the axis was harvested from 36 age- and gender-matched patients covering the human aging process from adolescence to senescence. In all specimens bone mineral density (BMD) was measured by peripheral quantitative computed tomography (pQCT). Morphological analysis after undecalcified processing of all specimens revealed a persistency of the subdental synchondrosis in 87% of all patients. Histological characterization of the subdental synchondrosis showed a cartilaginous structure interspersed with focal mineralization. Furthermore, static histomorphometric analysis revealed that trabecular bone volume and cortical thickness were significantly reduced within the base of the axis as compared to the dens and the corpus, respectively.

CONCLUSION

Taken together, these results provide evidence that the base of the axis is a structurally distinct region. Besides well-recognized biomechanical aspects, these results suggest that the structure of the base of the axis might contribute to the occurrence of fractures of the axis and offer an additional explanation for the observation of nonunion after type II dens fractures.

TECHNIQUES OF POSTERIOR C1–C2 STABILIZATION

INSTABILITY OF THE atlantoaxial complex may result from inflammatory, traumatic, congenital, neoplastic, or degenerative disorders and often requires surgical stabilization. Initial dorsal wiring techniques allow safe fixation but require rigid external immobilization and have been associated with high fusion failure rates. Rigid screw fixation techniques including transarticular screw fixation and C1–C2 rod-cantilever fixation offer higher fusion rates and less need for rigid immobilization but are more technically demanding. C1–C2 fixation using crossing C2 laminar screws offers rigid fixation but without the technical demands of C2 pars placement. The history and techniques of dorsal fixation of the atlantoaxial complex are reviewed, and the success rates and complications of each are discussed.

Anterior odontoid fixation using a 4.5-mm Herbert screw: the first report of 20 consecutive cases with odontoid fracture

BACKGROUND

Anterior screw fixation provides the best anatomical and functional results for odontoid process fracture (type II and "shallow" type III) with intact transverse ligament. The purpose of this study is to evaluate the clinical results of the 4.5-mm-diameter cannulated Herbert screw in the anterior odontoid fixation.

METHODS

From May 2003 to November 2005, 20 consecutive cases of types II and III odontoid process fractures were treated with anterior screw fixation using a 4.5-mm Herbert screw. The Herbert screw has double threads, with different pitches on the distal and proximal ends. It has no head, so it can be inserted through articular cartilage and buried below bone surface.

RESULTS

There were 16 male and 4 female patients whose ages ranged from 15 to 76 years (mean, 43.7 years). The fracture type was type II-A in 4 patients, II-N in 9 patients, II-P in 5 patients, and III in 2 patients. The range of follow-up was 3 to 36 months (mean, 18.6 months). There were an overall bone fusion rate in 17 cases (85%), fibrous union in 1 (5%), and nonunion in 2 (10%). Overall, complication unrelated to hardware occurred in the one (postoperative dysphagia) without complication-related hardware failure.

CONCLUSIONS

The Herbert screw is very useful in anterior fixation for types II and III odontoid process fractures. This series showed successful clinical results comparable with that of the 3.5-mm cannulated cancellous screw and distinct advantages over conventional screws in the aspect of biomechanical properties and less invasiveness.

The contemporary treatment of odontoid injuries

STUDY DESIGN

Review article.

OBJECTIVE

To outline current concepts regarding the assessment and treatment of odontoid fractures.

SUMMARY OF BACKGROUND DATA

Odontoid fractures account for 9% to 15% of adult, cervical spine fractures. These injuries usually result from hyperflexion or hyperextension of the cervical spine during low-energy impacts in the elderly or high-energy impacts in the young and middle aged. Neurologic injury associated with these fractures is rare.

METHODS

A review of pertinent literature was conducted. The information gleaned from this review was summarized.

RESULTS

Odontoid fractures should be evaluated with appropriate imaging to assess the fracture itself as well as exclude other contiguous or noncontiguous fractures. The Anderson and D'Alonzo classification system is most commonly used. True type I and III odontoid fractures are generally thought to be relatively stable and are often treated nonoperatively with immobilization. Type II fractures at the base of the odontoid are less stable, and there are differing opinions regarding the precise definition and optimal treatment of these injuries. Nonoperative treatment options for odontoid fractures include external immobilization with a collar or halo. Operative treatment options for odontoid fractures include one of several posterior C1-C2 fusion constructs or anterior odontoid fixation if the fracture pattern is amenable.

CONCLUSIONS

Despite the frequency of odontoid fractures, there is still much debate regarding the optimal treatment of these fractures, especially the type II fractures. This fact may be because of the absence of an ideal solution for this clinical problem. Certainly, prospective controlled clinical studies are needed.

Acute combination fracture of atlas and axis: "triple" anterior screw fixation in a 92-year-old man: technical note

BACKGROUND

The combination of odontoid and bilateral transarticular C1-C2 anterior screw fixation is a recent addition in treating C1-type II odontoid fractures. When feasible, it ensures early maximal stability, even if it slightly reduces the mobility of C1-C2 complex. We report a case of combination atlas-type II odontoid fracture that occurred in a 92-year-old man. The instability was treated with odontoid screw fixation and anterior bilateral C1-C2 transarticular screw fixation in a single stage. The aim of the article is to describe the feasibility of "triple" anterior screw fixation in the presence of C1-type II odontoid fracture.

METHODS

The diagnosis, treatment, and outcome of a 92-year-old patient with mild tetraparesis caused by C1-type II odontoid fracture were assessed.

RESULTS

Cervical x-rays, computed tomographic scan, and magnetic resonance imaging demonstrated a fracture of posterior arch of C1, associated with type II odontoid fracture and with presumable damage of C1 transverse ligament. Magnetic resonance imaging also showed a high cervical centromedullary area slightly hyperintense in T1-weighted images. Treatment consisted of odontoid and bilateral C1-C2 transarticular screw fixation with single anterior approach. The admission neurologic conditions improved and the patient was early mobilized.

CONCLUSIONS

The authors suggest that in presence of C1-type II odontoid fracture, the triple anterior screw fixation has to be taken into account as salvage procedure, especially if other methods of stabilization failed or cannot be safely performed. This technique seems to be safety feasible also in old patients, as our report and the experience of others confirm.

Subdental synchondrosis and anatomy of the axis in aging: a histomorphometric study on 30 autopsy cases

During skeletal development the two ossification centers of the odontoid process are separated from the corpus of the axis by a subdental synchondrosis. This synchondrosis is thought to close and disappear spontaneously in adolescence although this has never been studied in detail. The basis of the dens is of clinical relevance as type II dens fractures are located here. To characterize the morphological architecture of the axis with particular attention to the subdental synchondrosis, the complete axis was harvested from thirty age-matched and gender-matched patients of the three different age groups at autopsy. The subdental synchondrosis and the bone structure of the dens, the basis of the dens and the body of C2 were analyzed by radiography, histology and quantitative histomorphometry. At the macroscopic level the persistency of the subdental synchondrosis in the adult cervical spine was detected in 87% (26 of 30) of the specimens. Histomorphometry revealed a residual disc blastema with an average size of 25.8% of the sagittal depth of the basis of the dens at this level. Bony integration of the synchondrosis was poor throughout all ages. Histologically a cartilaginous matrix composition of the subdental synchondrosis persisted throughout all groups. The trabecular microarchitecture demonstrated a significant reduction of bone volume and trabecular number as well as an increased trabecular separation within the basis of the dens as compared to the corpus or the dens of C2. This histomorphometric data regarding a poor integration of the synchondrosis into the trabecular network and the reduced bone mass within the basis of the dens might offer a previously underestimated explanation for the occurrence of type II dens fractures and their association with pseudoarthrosis, respectively.

Surgical Treatment of Acute Type II and Rostral Type III Odontoid Fractures Managed by Anterior Screw Fixation

OBJECTIVES

In the present study, the authors comment on their experience with anterior odontoid screw fixation in the management of odontoid fractures, in an attempt to further assess the safety and the efficacy of this procedure.

MATERIALS AND METHODS

A retrospective analysis of 50 consecutive patients with reducible type II or rostral type III odontoid fractures, operated at our hospital with anterior odontoid screw fixation. Radiographic bony fusion, complications, and clinical outcome were evaluated.

RESULTS

Solid bony fusion was evident in 38 (90.5%) of the patients. One mechanical instrumentation-related complication occurred, without clinical significance. No other major complications related to the procedure were noted. A satisfactory range of motion in the cervical spine was observed in all patients.

CONCLUSIONS

Anterior odontoid screw fixation is a safe and effective procedure for the treatment of type II and rostral type III odontoid fractures. Compliance to the specific indications and contraindications of this operation is crucial for optimal outcome.

Results of long-term follow-up in patients undergoing anterior screw fixation for type II and rostral type III odontoid fractures

STUDY DESIGN

Retrospective analysis of the fusion rate of a group of 38 patients having undergone anterior screw fixation for type II and "shallow" type III odontoid fractures. OBJECTIVE.: To determine primarily the long-term fusion rate after anterior screw fixation and to study the clinical characteristics of patients that have a statistically significant or nonsignificant influence on successful outcome.

SUMMARY OF BACKGROUND DATA

Long-term outcome of anterior screw fixation for odontoid fractures has been evaluated in very few studies. This information should be critical for further establishing this technique as a major therapeutic strategy for these cases.

METHODS

Thirty-eight patients, 25 males and 13 females (with mean age 48.4 +/- 0.4 years), with type II and rostral type III odontoid fractures, underwent anterior cannulated screw fixation during a 62-month period. Radiologic examination of the cervical spine with plain radiographs was performed at 6 weeks, and 2, 6, 12, and 24 months, while computerized tomography of the upper cervical spine (C1-C3) was obtained at 6 months after surgery. Follow-up was available for 31 patients, and the follow-up time ranged from 39 to 87 months (mean 58.4).

RESULTS

Radiographic evaluation of the follow-up group showed satisfactory bony fusion and no evidence of abnormal movement at the fracture site in 27 (87.1%) patients. Pseudarthrosis developed in 4 (12.9%) patients; however, 3 (9.6%) of them without instability and 1 (3.2%) with instability. One (3.2%) patient had an instrumentation failure without instability.

CONCLUSIONS

In our series, anterior odontoid screw fixation comprised a safe therapeutic modality with high stability and low mechanical failure rates during short-term and long-term follow-up.

Proposal of a modified, treatment-oriented classification of odontoid fractures

BACKGROUND CONTEXT

The classification scheme of odontoid fractures described by Anderson and D'Alonzo is the one most commonly used. However, uncertainty exists in the distinction between Type II and "shallow" Type III fractures. Moreover, fractures at the base of the odontoid (Anderson and D'Alonzo Type II) include a spectrum of injury patterns.

PURPOSE

To modify the Anderson and D'Alonzo classification of odontoid fractures based on current clinical treatment options.

STUDY DESIGN

Proposal of a modified classification system for odontoid fractures.

METHODS

A more precise distinction between Type II and III fractures based on the presence/absence of C1-C2 facet involvement is proposed. A modified classification of Type II fractures based on fracture line obliquity, displacement and comminution is then proposed, because these are factors deemed to influence management. To evaluate the reproducibility of this classification, 52 odontoid fractures were reviewed and classified by four attending spine surgeons and three spine fellows.

RESULTS

There was substantial agreement (at least five of seven respondents) in 70% of cases. The overall kappa value for the modified classification system was 0.48, indicating moderate agreement, and there were no differences in kappa values between attending spine surgeons and fellows.

CONCLUSIONS

The reproducibility of this system was demonstrated by the moderate agreement observed when applied to odontoid fractures at our institution. The proposed utility of this system is its ability to guide clinical decision making in the treatment of odontoid fractures. Prospective application of this modified classification system and suggested treatment options is now required.

Type I odontoid fracture--case report

A 17-year-old man presented with sleeping tendency, tenderness of the back of the neck, and left upper monoplegia after a motorcycle accident. Three-dimensional computed tomography on the 2nd hospital day clearly revealed a type I odontoid fracture. His injuries were treated conservatively and he was discharged on the 60th hospital day, with sequelae due to the cervical root avulsion injuries. Type I odontoid fracture is rare and may be caused by coronal distraction of the head and neck area.

Non-rigid immobilisation of odontoid fractures

Despite various reports on the management of odontoid fractures, there is no consensus on the subject, and the appropriate treatment still remains controversial. While untreated fractures or fractures treated only with a cervical orthosis seem to have the highest rate of non-union, the need for rigid external stabilisation has never been substantiated. In a retrospective analysis we reviewed 26 patients with acute type II and III fractures of the odontoid, treated with a cervical orthosis only. Study inclusion was limited to fractures that had a fracture gap of less than 2 mm, an initial antero-posterior displacement of less than 5 mm and angulation of less than 11 degrees, less than 2 mm displacement on lateral flexion/extension views, and were without neurological deficits. These fractures were defined as stable. There were 19 (73.1%) type II and 7 (26.9%) type III fractures; in 10 (38.5%) of these fractures the odontoid was displaced and/or angulated. The overall complication rate was 11.4% ( n=3). One patient suffered from pulmonary embolism, in two patients (7.7%) with initially minimally displaced fractures, secondary internal stabilisation had to be performed because of persistent instability. In 20 (77%) of the remaining fractures healing was uneventful. In 4 nondisplaced fractures (15%) fibrous union was documented. Three of these patients were over 65 years old. The overall fusion rate was 73.7% for type II and 85.7% for type III fractures. At follow-up 39% of the patients were free of symptoms; however, the clinical outcome did not correlate with the radiological findings. According to our findings, stable type II and type III fractures of the odontoid can be successfully treated with non-rigid immobilisation, even if they are displaced. A thorough assessment of the stability of the odontoid with lateral flexion/extension views or dynamic fluoroscopy is recommended to evaluate the appropriate treatment. Non-rigid immobilisation may be an option in selected cases with stable injuries.

Halo jacket in odontoid fractures type II and III

The treatment of odontoid fractures remains controversial. The late results of 14 patients with Anderson D'Alonzo type II and III treated with halo jacket from 1995 to 1999 are presented. The fractures were reduced under image intensifier and stabilized by halo jacket. The immobilization period was 12 weeks. After 1 year, the fracture was roentgenologically consolidated in 12 out of 14 patients (85.7%), and all the patients were without neurological deficit. Nine patients (64.3%) were without subjective complaints, five had a reduced range of motion. Painful motion appeared in four patients (28.6%), and cervical stiffness was noted in five (35.7%). We recommend halo jacket for the treatment of most type II and III odontoid fractures which are unstable or displaced 6 mm and more, except for patients with tetraplegia. Fractures with minimal displacement and without neurological deficit were treated conservatively with rigid collars. In our institution, internal fixation was performed in selected cases. The presence of neurological deficit and the anatomic properties of the fracture site crucially influence the choice of treatment.

Diagnosis and management of a metastatic tumor in the atlantoaxial spine

STUDY DESIGN

A retrospective review of a prospectively maintained spine database was conducted.

OBJECTIVES

To review the experience of a large multidisciplinary tertiary referral oncology center in diagnosing and managing metastatic disease of the atlantoaxial spine in the era of magnetic resonance imaging, and to establish treatment parameters.

SUMMARY OF BACKGROUND DATA

Published literature on the topic is limited, with conflicting opinions. Although external beam radiation therapy has proven value, some clinicians support aggressive surgical management.

METHODS

This study included all the patients who presented over a 6-year period to Memorial Sloan-Kettering Cancer Center with metastatic disease to the atlantoaxial spine. Demographics and diagnoses were obtained. Magnetic resonance images, computed tomography scans, and plain radiographs were reviewed. At presentation, patients with normal alignment or minimal subluxation were considered for nonoperative therapy, either external beam radiation therapy or chemotherapy. Surgery was reserved for patients with significant fracture subluxations, including atlantoaxial displacement more than 5 mm or angulation exceeding 11 degrees with displacement more than 3.5 mm. Additional operative indications were prior external beam radiation therapy administered to overlapping spinal ports, unknown primary pain, and persistent pain after nonoperative therapy. Patient outcome was evaluated for pain relief, neurologic outcomes, degree of spine involvement, and survival.

RESULTS

Symptomatic metastatic tumor involving the atlantoaxial spine was diagnosed in 33 patients. The mean age at presentation was 57 years. Histologic diagnoses varied widely. All the patients presented with severe mechanical neck pain, but no patient had myelopathy related to epidural tumor or fracture subluxation. Of these 33 patients, 25 patients initially were treated nonoperatively with either external beam radiation therapy (n = 23) or chemotherapy (n = 2), and 8 patients underwent initial operation. In this nonoperatively treated group, 23 of the 25 patients had significant pain resolution until death or last follow-up assessment. Five patients required subsequent operation: three for significant fracture subluxations and two after neoadjuvant chemotherapy. Of the fracture subluxations, two were present before external beam radiation therapy, and one was delayed from rapid tumor progression. Posterior instrumentation was performed in the 13 patients who underwent surgery. No patient required anterior decompression and stabilization. Significant pain resolution was achieved in all the surgically treated patients.

CONCLUSIONS

External beam radiation therapy was used successfully to treat patients with normal alignment or minimal subluxation. Selected patients warrant immediate stabilization. Patients with persistent pain and inability to wean from a hard collar after nonoperative therapy also should be considered for surgery. Posterior stabilization provides pain relief and neurologic preservation or recovery without the need for anterior decompression.

Isolated fractures of the axis in adults

FRACTURES OF THE ODONTOID:

STANDARDS

There is insufficient evidence to support treatment standards.

GUIDELINES

Type II odontoid fractures in patients 50 years and older should be considered for surgical stabilization and fusion.

OPTIONS

Type I, Type II, and Type III fractures may be managed initially with external cervical immobilization. Type II and Type III odontoid fractures should be considered for surgical fixation in cases of dens displacement of 5 mm or more, comminution of the odontoid fracture (Type IIA), and/or inability to achieve or maintain fracture alignment with external immobilization. TRAUMATIC SPONDYLOLISTHESIS OF THE AXIS (HANGMAN'S FRACTURE):

STANDARDS

There is insufficient evidence to support treatment standards.

GUIDELINES

There is insufficient evidence to support treatment guidelines.

OPTIONS

Traumatic spondylolisthesis of the axis may be managed initially with external immobilization in most cases. Surgical stabilization should be considered in cases of severe angulation of C2 on C3 (Francis Grade II and IV, Effendi Type II), disruption of the C2--C3 disc space (Francis Grade V, Effendi Type III), or inability to establish or maintain alignment with external immobilization. FRACTURES OF THE AXIS BODY (MISCELLANEOUS FRACTURES):

STANDARDS

There is insufficient evidence to support treatment standards.

GUIDELINES

There is insufficient evidence to support treatment guidelines.

OPTIONS

External immobilization is recommended for treatment of isolated fractures of the axis body.

Acute respiratory compromise associated with flexed cervical traction after C2 fractures

STUDY DESIGN

Acute respiratory compromise is occasionally observed in a subgroup of patients with upper spinal injuries involving the C2 vertebrae. A retrospective review was performed to identify fracture types and risk factors for early respiratory deterioration following injury to the upper cervical spine.

OBJECTIVES

To examine the frequency of respiratory complications encountered following traction manipulation of specific upper cervical spinal injuries involving the C2 vertebrae.

SUMMARY OF BACKGROUND DATA

Major complications related to cervical skeletal traction are uncommon. Respiratory compromise with occasional mortality has been observed. Risk factors for acute respiratory failure are unknown.

METHODS

The medical records of 166 consecutive patients with fractures of the C2 vertebrae admitted between January 1994 and July 1998 to a regional spinal cord injury center were examined. Demographic data, injury subtype, fracture displacement, respiratory status, treatment method, and outcome at discharge were examined. Patients with comorbidities compromising respiratory function were excluded.

RESULTS

One hundred fifty-five patients met the inclusion criteria of this study. Sixty-one patients had Type II odontoid fractures of which 53 were displaced (32 posteriorly and 21 anteriorly). In addition, there were 21 patients with Type III odontoid fractures, 33 with axis C2 body fractures, 32 with Hangman's fractures, and eight patients with an os odontoideum. Thirteen of 32 patients with posteriorly displaced odontoid fractures experienced acute respiratory compromise following reduction with cervical skeletal traction and immobilization, while only three of the remaining 123 patients had respiratory difficulties. Respiratory distress as a consequence of cervical spine fractures resulted in three deaths. Two of these patients had posteriorly displaced Type II odontoid fractures whose airway could not be emergently intubated.

CONCLUSION

Frequent respiratory deterioration (40% of patients) during acute management of posteriorly displaced Type II odontoid fractures after reduction was observed. Physicians must be aware that cervical flexion in the treatment of posteriorly displaced odontoid fractures may significantly increase the risk of airway obstruction due to the presence of acute retropharyngeal swelling. This may be avoided with elective nasotracheal intubation in this upper cervical spine fracture subtype.

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.

Direct anterior screw fixation for recent and remote odontoid fractures

OBJECT

The management of odontoid fractures remains controversial. Only direct anterior screw fixation provides immediate stabilization of the spine and may preserve normal C1-2 motion. To determine the indications, optimum timing, and results for direct anterior screw fixation of odontoid fractures, the authors reviewed the surgery-related outcome of patients who underwent this procedure at two institutions.

METHODS

One hundred forty-seven consecutive patients (98 males and 49 females) who underwent direct anterior screw fixation for recent (< or = 6 months postinjury [129 patients]) or remote (> or = 18 months postinjury [18 patients]) Type II (138 cases) or III (nine cases) odontoid fractures at the University of Utah (94 patients) and National Institute of Traumatology in Budapest, Hungary (53 patients) between 1986 and 1998 are included in this study (mean follow up 18.2 months). Data obtained from clinical examination, review of hospital charts, operative findings, and imaging studies were used to analyze the surgery-related results in these patients. In patients with recent fractures there was an overall bone fusion rate of 88%. The rate of anatomical bone fusion of recent fractures was significantly (p < or = 0.05) higher in fractures oriented in the horizontal and posterior oblique direction (compared with anterior oblique), but this finding was independent (p > or = 0.05) of age, sex, number of screws placed (one or two), and the degree or the direction of odontoid displacement. In patients with remote fractures there was a significantly lower rate of bone fusion (25%). Overall, complications related to hardware failure occurred in 14 patients (10%) and those unrelated to hardware in three patients (2%). There was one death (1%) related to surgery.

CONCLUSIONS

Direct anterior screw fixation is an effective and safe method for treating recent odontoid fractures (<6 months postinjury). It confers immediate stability, preserves C1-2 rotatory motion, and achieves a fusion rate that compares favorably with alternative treatment methods. In contradistinction, in patients with remote fractures (> or = 18 months postinjury) a significantly lower rate of fusion is found when using this technique, and these patients are believed to be poor candidates for this procedure.

Management of type II dens fractures: a case-control study

STUDY DESIGN

A case-control study of patients with isolated type II dens fractures treated with halo vest immobilization.

OBJECTIVES

To evaluate age as a risk factor for failure of halo immobilization in patients with type II dens fractures.

SUMMARY OF BACKGROUND DATA

The literature reports an average fusion rate of approximately 70% in patients with type II dens fractures treated by halo vest immobilization. Although many investigators have examined patient age as a risk factor for nonfusion using halo immobilization, all studies have been supported only by Class III data. These studies, consequently, carry little or no statistical significance. Therefore, a case-control study based on Class II data was designed to evaluate age as a risk factor for failure of halo vest immobilization in patients with type II dens fractures.

METHODS

Thirty-three patients with isolated type II dens fractures treated with halo vest immobilization at the University of Iowa Hospitals and clinics between 1983 and 1997 were included. Type II fractures were defined with plain radiography as per the Anderson-D'Alonzo classification. Cases were defined as nonfusions after halo immobilization, whereas control subjects represented successful bony unions attained with halo immobilization.

RESULTS

When the case and control groups were compared, there was no significant difference between the groups in the presence of concomitant medical conditions, sex, the amount of fracture displacement, the direction of fracture displacement, the length of hospital stay, or length of follow-up. Age more than 50 years was found to be a highly significant risk factor for failure of halo immobilization (P = 0.002; Fisher's exact test, two-tailed). The odds ratio of these data indicate that the risk of failure of halo immobilization is 21 times higher in patients aged 50 years or more.

CONCLUSIONS

Surgical intervention should be considered in those patients aged 50 years or more who have a type II dens fracture, if it can be accomplished with acceptable risk of morbidity and death.

Posterior C1-C2 transarticular screw fixation in the treatment of displaced type II odontoid fractures in the geriatric population--review of seven cases

BACKGROUND

Seven geriatric patients presented with displaced Type II odontoid fractures. All patients underwent a posterior C1-C2 transarticular fixation between November 1994 and December 1996. Ages ranged between 63 and 88 years.

METHODS

Fractures were treated with placement of bilateral transarticular screws, allowing immediate fixation, except in one patient, for whom only a unilateral screw was used. An autograft interspinous strut was also placed, allowing three-point fixation. Mean follow-up was 10.6 months.

RESULTS

Six patients received rigid fixation and developed a stable union. One patient died before any follow-up could be obtained. Two other patients died within 1 year of unrelated causes. The remaining four patients remain active and independent. One intraoperative vertebral artery injury was identified. No clinical sequalae were noted.

CONCLUSION

Posterior transarticular screw fixation is a reasonable option in treating these controversial fractures. Seven geriatric patients tolerated this surgery well, and were mobilized early, avoiding complications related to external immobilization.

Functional outcome of surgically and conservatively managed dens fractures

STUDY DESIGN

Fifty-seven patients with dens fractures were identified from 1986 to 1996 at the authors' institution. Forty-six were available for reevaluation by two independent observers with a mean follow-up period of 26 months.

OBJECTIVE

To determine by age and fracture type which treatment regimen provided the best functional outcome in patients with dens fractures.

SUMMARY OF BACKGROUND DATA

There were no Type I fractures, but there were 37 Type II and 20 Type III fractures. Twenty-nine patients were under 60 years of age, and 28 were 60 years and older. Six patients had been treated by immediate C1-C2 posterior fusion, and five received treatment with a Philadelphia collar only. Forty-six patients were placed in a halo thoracic immobilizer with a symptomatic nonunion rate of 19.5%. These patients ultimately required posterior cervical fusion.

METHODS

Final functional outcome, level of pain, and cervical range of motion were all statistically evaluated using multivariate analysis (Wilcoxon's two-sample test). The influence of age, fracture type, and treatment method were determined.

RESULTS

There were no cases of short- or long-term neurologic deterioration in any of the patients in the study group. There was a significantly higher rate of complications associated with halo use in the older population. Pain scores were higher in Type II fractures and in patients treated conservatively with halo immobilization, especially those patients over 60 years of age. No statistically significant difference in these parameters were found. Older patients treated surgically did not have a better functional outcome score than those treated nonoperatively (P < 0.8). Persons over 60 years of age treated in a halo had a significantly (P < 0.05) decreased range of motion when compared with younger patients treated similarly.

CONCLUSION

Patients over 60 years of age with a dens fracture had a higher complication rate and lower cervical range of motion when treated conservatively with a halo. Final functional outcome and overall pain levels, however, did not differ significantly by age group or treatment modality.

Acute axis fractures. Analysis of management and outcome in 340 consecutive cases

STUDY DESIGN

Retrospective review of acute axis fractures treated at a tertiary referral center.

OBJECTIVE

To determine the optimal treatment of axis fractures based on 340 cases from a single institution.

SUMMARY OF BACKGROUND DATA

Axis fractures account for almost 20% of acute cervical spine fractures. However, their management and the clinical criteria predictive of nonoperative failure remain unclear.

METHODS

Admission imaging studies and clinical variables were obtained for 340 consecutive axis fracture patients. Fractures were classified as as odontoid Type I, II, or III with dena displacement on admission roentgenograms; hangman's fractures of Francis grade and Effendi type; and miscellaneous fractures. Treatment methods were documented, and outcomes were based on dynamic lateral roentgenograms, clinical examination, or telephone interviews at last follow-up.

RESULTS

Follow-up data were available in 92% of cases. Type II odontoid fractures comprised 35% of all axis fractures, were the most difficult to treat, and had the highest nonunion rate (28.4%). Odontoid displacement of 6 mm or more was associated with Type II nonunion (chi-square = 33.74, P < 0.0001). Patients underwent surgical fusion if fracture alignment could not be maintained by an external orthosis, or if they had odontoid fractures with transverse ligament disruption, Type II odontoid fractures with dens displacement of at least 6 mm, or hangman's fractures of severe Francis grade or Effendi type.

CONCLUSIONS

Type II odontoid fractures have the highest nonunion rate and were associated with dens displacement of 6 mm or greater. Early surgical fusion is recommended for acute fracture instability despite external immobilization, transverse ligament disruption, Type II odontoid fractures with dens displacement of at least 6 mm on admission, or severe Francis grade or Effendi-type hangman's fractures. Otherwise, nonoperative management is sufficient.

Cervical spine fractures in the elderly

BACKGROUND

Cervical spine fractures in the elderly are relatively common. The management of such injuries may be complicated by underlying medical debility and osteopenia as well as reduced tolerance to halo immobilization.

METHODS

Over a 1-year period, 43 cervical spine fractures were treated at our institution. Ten (23%) were in persons 70 years of age or older. This retrospective analysis describe the clinical features, treatment, and outcome of these 10 elderly patients. All fractures in this patient population involved the atlantoaxial complex, including five combination C1-C2 fractures. Six patients were treated with early halo immobilization and three were initially managed with a rigid cervical collar. Three patients required posterior cervical fusion.

RESULTS

Of the six patients undergoing halo immobilization, five progressed to osseous union. Three patients were immobilized in a Philadelphia collar resulting in one osseous union, one nonunion, and one death. Three patients underwent posterior cervical fusion with subsequent osseous union in all three.

CONCLUSIONS

Although external immobilization with a halo device is our treatment of choice for most C1 and C2 fractures in elderly patients, a Philadelphia collar is useful in select cases when halo immobilization or early surgical fusion is contraindicated. Posterior cervical fusion can be safely and effectively performed in elderly patients and should be strongly considered for initial therapy in the elderly with fracture types unlikely to progress to osseous union with external immobilization alone.

Fatal transdental posterior rotary subluxation of the cervical spine. A case report

STUDY DESIGN

The cervical spine of an 86-year-old man known to have a fracture of the odontoid process was removed at autopsy and dissected.

OBJECTIVES

To establish the cause of death, which was not apparent.

SUMMARY OF BACKGROUND DATA

Ruptures of the vertebral arteries in patients with fractures of the odontoid process are rare. Only a few reports are published in the literature. Those that address postmortem findings in patients with fractures of the odontoid process do not make any reference to associated capsular and ligamentous injuries and the resultant instabilities.

METHODS

Because of legal constraints, the cervical spine was removed en bloc 1 week after the patient's death and carefully dissected.

RESULTS

In addition to the known bony injury, rupture of the left vertebral artery, epidural hematoma, disruption of the posterior atlantoaxial ligaments, hemorrhage into the anterior ligamentous structures, rupture of the capsule of the right atlantoaxial joint, and stretching of the capsule of the left joint were found to be present. Displacement of the spinal cord by an epidural hematoma secondary to rupture of the left vertebral artery was recorded as the apparent cause of death. The rupture had obviously been caused by the abnormal rotation of the atlas on the axis in a clockwise direction.

CONCLUSIONS

Both the fatal outcome and the pathologic examination showed that established management concepts, particularly screw fixation of a fractured odontoid process, should be reconsidered in light of the potential occurrence of transdental posterior rotary subluxation. Because the incidence of capsular, ligamentous, and vascular injuries associated with fractures of the odontoid process is still poorly understood, more autopsies would be needed. The case also raises the question of whether, in an elderly patient like ours, a fracture of the odontoid process should prompt immediate surgical stabilization.

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.

Dysphagia and deformity after undetected odontoid fracture in elderly patients

Trauma in elderly patients is often difficult to evaluate and neck injuries are probably more common than is documented. A case is described of a missed odontoid peg fracture with the unusual presentation of dysphagia and a rapidly developing cervicodorsal kyphos (head falling forward), which may well have been anticipated at several points in the management chain. The lessons to be learned are outlined, together with the subsequent management of this patient.

Nonunion of a type II odontoid fracture after an apparent radiographic fusion: case report

The type II odontoid fracture, initially described by Anderson and D'Alonzo, is the most common axis fracture. Several factors that predict the need for operative intervention have been discussed in the literature; however, the initial treatment remains somewhat controversial. We present the case of a 20-year-old woman who suffered a Type II odontoid fracture during a skiing accident. She was managed initially with halo-vest immobilization, and after 12 weeks, bony fusion was documented by plain spine radiographs and tomography. Routine follow-up cervical spine films at 8 months after her injury revealed no union at the previous fracture site and resultant atlantoaxial instability. A posterior C1-C2 fusion was therefore performed, leading to a long-term solid bony fusion. There are no previous reports in the literature describing a nonunion after radiographically documented healing of a Type II odontoid fracture. We present this case in order to emphasize the importance of scheduled follow-up examinations, including cervical spine films, for at least 12 months after a documented fusion. Further reports of similar cases may generate a more thorough understanding of the pathogenesis of delayed nonunion and may elicit factors that will predict its development.

Neurological and skeletal outcomes in 113 patients with closed injuries to the cervical spinal cord

Neurological and skeletal outcomes were evaluated in 113 patients for one year following closed lower cervical spinal cord injuries. The extent of neurological recovery did not depend on surgical versus nonsurgical management, or the degree of spinal angulation, vertebral displacement, spinal stenosis, or inferred mechanism of injury based on the initial plain cervical x-rays. Assessment of skeletal outcomes demonstrated significantly less vertebral angulation, more rapid stabilization, and less anterior callus formation among the patients in the surgical group. In addition, the surgical patients had marginally shorter lengths of hospitalization.

Vertical odontoid fracture. Case report

A case of vertical odontoid fracture is presented in which a concomitant fracture of the skull indicated possible pathogenetic mechanisms. The radiological diagnosis and the management of this case are discussed.

Type I fractures of the odontoid process: implications for atlanto-occipital instability. Case report

Only four cases of Type I odontoid fracture have been previously described in the English literature. Most authors consider this lesion to be stable, although the mechanism(s) of injury has not been clearly elucidated. A case of Type I odontoid fracture in association with atlanto-occipital and atlantoaxial dislocation resulting in death is presented. The normal ligamentous anatomy is reviewed and proposed mechanisms for this injury are discussed. The radiographic features of all reported cases of this type are reviewed. It is proposed that the Type I odontoid fracture is a likely manifestation of atlanto-occipital instability and rarely occurs as an isolated or stable injury.

Acute axis fractures: a review of 229 cases

Eighteen percent of acute cervical spine fractures involve the C-2 vertebra. The odontoid Type II fracture is the most common axis fracture and it is also the most difficult to treat. The degree of odontoid dislocation has been identified as the single most important fracture feature that helps separate those patients who have a high likelihood of healing with nonoperative therapy from those who are likely to fail nonoperative therapy and should be offered early surgical stabilization. The difference is statistically significant (p less than 0.001, x2 = 30.20). The present series includes 229 patients with acute axis fractures. Follow-up data were available in 92% of these patients, for a median duration of 4 years 9 months. Treatment guidelines and results are offered for each subtype of axis fracture based on this experience.

Acute injuries of the axis vertebra

A retrospective analysis of 165 patients admitted to Hermann Hospital with acute injuries of the axis vertebra revealed 68 (41%) dens fractures, 62 (38%) cases of traumatic spondylolisthesis ("hangman's" fracture), 21 (13%) extension teardrop fractures, 10 (6%) hyperextension dislocations, and 2 (1.0%) fractures each of the laminae and spinous processes. Of the 68 dens fractures, none (0%) were of the Anderson and D'Alonzo Type I; 21 (31%) were Type II ("high"); and 47 (69%) were Type III ("low"). The 62 traumatic spondylolistheses included 13 (21%) Effendi type I, 35 (56%) type II and 3 (5%) type III. This review disclosed an additional 11 (18%) patients with an atypical variety of traumatic spondylolisthesis, not previously reported, in which one or both fractures involved the posterior cortex of the axis body. Of the axis injuries 31 (18%) were limited to the axis body alone. Of these, 21 (61%) were hyperextension teardrop fractures and 10 (32%) were hyperextension dislocations. Axis injuries were associated with acute injuries of other cervical vertebrae in 14 (8%) of the patients.