SPINE Volume 33, Number 26, pp 2881–2886 ©2008, Lippincott Williams & Wilkins

Nonoperative Management of Type II Odontoid Fractures in the Elderly Florentius Koech, MB ChB, MMed (GSurgery),* Helen M. Ackland, MHSc,†‡ Dinesh K. Varma, MBBS, MD, FRANZCR,§¶ Owen D. Williamson, MBBS, GradDipClinEpi, FRACS, FAOrthA,‡ and Gregory M. Malham, BSc, MB ChB, FRACS*¶

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 ⱖ65 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

From the *Department of Neurosurgery and †National Trauma Research Institute, The Alfred Hospital; ‡Department of Epidemiology and Preventive Medicine, Monash University; §Department of Radiology, The Alfred Hospital; and ¶Department of Surgery, Monash University, Melbourne, Australia. Acknowledgment date: February 11, 2008. Revision date: July 3, 2008. Acceptance date: August 6, 2008. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. Presented at the Annual Scientific Meeting of the Spine Society of Australia, April 20 –22, 2007, Hobart, Australia. Institutional ethics approval has been obtained. Reprints not available from the author. Address correspondence to Gregory Malham, BSc, MB ChB, FRACS, Department of Neurosurgery, The Alfred Hospital, Commercial Rd, Melbourne, Australia, 3004; E-mail: [email protected]

been treated with halothoracic bracing in preference to cervical collars. Stable fibrous union may be an adequate aim of management in elderly patients. Key words: odontoid, Type II fracture, halothoracic brace, cervical collar, elderly. Spine 2008;33:2881–2886

Fractures of the second cervical vertebra account for approximately 15% to 20% of acute cervical spine fractures.1–3 In particular, 9% to 18% of all cervical spine fractures involve the odontoid process.1,2,4 Dens or odontoid fractures are generally attributed to hyperflexion or hyperextension and occur most frequently in 2 specific groups: young patients who have sustained high impact trauma-related injuries, and the elderly, for whom low energy falls constitute the most prevalent mechanism of injury,2,5 resulting in isolated trauma.6 Complications after odontoid fracture in the elderly population are common.2,5 Classification of odontoid fractures into subtypes according to fracture level was initially described by Anderson and D’Alonzo.7 Oblique fractures of the tip of the odontoid process above the transverse ligament are classified as Type I fractures, considered to be stable injuries in isolation, and unite well.7,8 Fractures through the C2 vertebral body, Type III fractures, are also considered stable7 unless markedly displaced9 and are associated with a high rate of union.1 Type II fractures occur at the junction of the odontoid process and the C2 vertebral body and hence are considered to be unstable and easily displaced.7,8 The inherent instability of this fracture subtype results from the dissociation of the apical, alar, and transverse ligaments, which attach to the odontoid process, the atlas and the skull base, from the vertebral body of the axis.10 Type II fractures are the most common odontoid injuries,5,8,11,12 occurring in 38% to 46% of cases in the general population2,3 and in 82% to 95% of elderly patients with odontoid fracture.5,13 After the recognition of management difficulty when free fragments are present as a feature of comminution in Type II fractures, Hadley et al,14 suggested the inclusion of a subclass Type IIA fracture. Such fractures are rare, but are prone to nonunion, hence surgical stabilization in the initial period is recommended. At our institution, the recognized risks associated with the initial surgical management of Type II odontoid fractures in the elderly population render conservative management preferable unless gross instability is present. Secondary operative fixation is reserved for 2881

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cases of failed conservative management; nonunion with radiographically demonstrated instability, recurrent dislocation, or increased neurologic deficit. To assess the outcome of nonoperative treatment of Type II odontoid fractures in the elderly patient population, a retrospective cohort study was conducted, and prospective functional follow-up was undertaken. Materials and Methods Consecutive patients aged ⱖ65years of age who had sustained Type II odontoid fractures, according to Anderson and D’Alonzo’s classification,7 and were admitted to a Level 1 trauma center between January 1997 and December 2004, were identified via the institution’s prospective neurosurgery database. Patients who underwent primary operative stabilization, as a result of radiographically demonstrated gross instability, were excluded. Institutional ethics approval was obtained. All patients had undergone diagnostic cervical anteroposterior, lateral, and odontoid plain radiography and high-resolution computed tomography (CT) on admission. The admission CT scan protocol included 1-mm axial imaging with sagittal and coronal reformats from the skull base to C3 and 3-mm axial imaging with sagittal reformats from C2 to T4/5. Fracture management included the application of a halothoracic brace and/or treatment in a cervical collar. In our institution, management decisions in nonoperative stabilization are based on assessment of existing patient comorbidities, the preinjury level of independent mobilization, and the knowledge of significant complications associated with halothoracic bracing in the elderly population. After treatment, lateral dynamic cervical plain radiography was performed to assess stability. Data including patient demographics, mechanism of injury, fracture classification, presence/absence of neurologic deficit, associated nonspinal injuries, fracture management, and complications were obtained from the neurosurgery database and patient medical records. Follow-up assessment included patient interview to determine persistent pain and disability and radiologic review to determine fracture union and stability. Pain at follow-up was assessed using an 11-point numerical pain scale with a score of 0 indicating no pain and a score of 10 indicating maximum pain. Pain scores were subsequently categorized into groups denoting no pain and mild, moderate, moderate/severe, and severe pain. Long-term functional outcome was assessed using the Neck Disability Index15 and a modification of the SmileyWebster Scale16,17 (Table 1). Fracture union was determined using fine-cut CT, and dynamic radiographs were assessed for stability, which we defined as the absence of demonstrable movement at the fracture site during flexion and extension of the cervical spine. Fracture nonunion was defined according to Schatzker et al18 as (i) an odontoid defect with sclerosis of both fragments (vascular pseudarthrosis), (ii) an odontoid defect with resorption of both fragments (atrophic pseudarthrosis), (iii) an odontoid defect with loss of cortical continuity, or (iv) demonstrable movement of the odontoid fragment on flexion/ extension radiography. The presumption of fibrous union was noted if applicable; fibrous union was presumed if there was an absence of osseous union but no demonstrable movement on flexion and extension views. Associations between categorical variables were identified using ␹2 tests and adjusted using logistic regression. (SPSS

Table 1. Functional Outcome Scale17 (Modification of the Smiley-Webster Scale16) Score

Functional Level

Functional Ability

1

Excellent

2

Good

3

Fair

4

Poor

No pain, no noticeable change in range of movement, return to full premorbid activities, neurologically intact Occasional pain, noticeably decreased range of movement, any change from premorbid activity, neurologically intact Moderate pain, changes in range of movement, which adversely affect daily activities or any isolated neurologic event Significant pain, incapacity, catastrophic neurologic event or death

WIN13.0, SPSS Inc., Chicago, IL and Stata: Release 8, Stata Corp., TX).

Results There were 80,207 trauma presentations during the 8-year data collection period. Of these, 65 patients aged ⱖ65 years of age were identified as having sustained Type II odontoid fractures, representing 0.08% of presentations. Four patients died from other trauma-related causes during the initial inpatient period, 5 died from unrelated cardiac or respiratory failure, and 6 failed to present for follow-up. Eight patients were treated via primary operative stabilization, and hence were excluded. As a result, 42 patients completed the study, of whom 33 (79%) were female. The median age was 80 years (range: 67–91 years). Falls in 23 cases (55%) and road traffic accidents in 19 cases (45%) constituted the most common mechanisms of injury. Type II odontoid fractures were sustained in 38 cases (90.5%), whereas 4 patients were diagnosed with Type IIA fractures. Thirty patients (71%) had isolated odontoid fractures only. The remaining patients sustained additional traumatic injuries, including head (5 patients), thoracic, pelvic, abdominal, and/or orthopaedic injuries. Odontoid fracture management included treatment in a cervical collar alone in 10 cases (24%), halothoracic bracing alone in 9 cases (21.5%), or halothoracic bracing followed by the application of a cervical collar in 23 patients (55%). Patients using cervical collars were managed in either a Philadelphia (Philadelphia Cervical Collar Co., NJ) or Aspen (Aspen Medical Products Inc., Long Beach, CA) collar for 12 to 24 weeks. Overall, 4 patients (9.5%) developed complications including cervical collar-related decubitus ulceration in 1/10 cases, halothoracic vest-related pressure ulceration in 2/32 cases, decreased halothoracic pin tension in 1 case, and residual neck stiffness in 2 cases (2 patients developed more than 1 complication). There were no halothoracic pinsite infections in our series. Two patients had secondary operative management for failed conservative treatment, as evidenced by poor stability as demonstrated on lateral dynamic cervical radiography.

Type II Odontoid Fractures • Koech et al 2883

Figure 1. Computed tomographic view of Type II odontoid fracture in an 84-year-old female at 10 months post fall. Note the lack of osseous fusion.

The majority of patients were followed up at 24 months post injury (32 patients) with the remaining 10 patients completing follow-up assessment at 9, 10, 12, or 15 months. Hence the median time to follow-up was 24 months. Of the 10 patients treated in cervical collars alone, 5 achieved osseous fracture fusion, but 9 achieved radiographically demonstrated stability. In the patients in whom stability was demonstrated in the absence of bone healing, fibrous fracture union was presumed to have occurred (Figures 1–3). One patient in this group sustained Type IIA fracture, which failed to fuse but was stable on subsequent flexion/extension radiography. Residual pain in this group was reported as ranging from no pain to moderate pain in 9 patients. One patient (patient A) had severe residual pain (Table 2). According to the Neck Disability Index, the majority of patients treated in cervical collars reported mild disability (8 patients) with 1 patient (patient A) reporting severe disability (Table 2). The modified Smiley-Webster functional scale revealed that the majority of patients treated in collars had good (6 patients) or fair (2 patients) outcomes. Patient A, an 80-year-old female who sustained a Type II odontoid fracture as a result of a low fall, achieved neither radiographic fusion nor stability after treatment in a cervical collar for 12 weeks, resulting in ongoing severe neck pain, severe disability, and poor functional outcome at follow-up. Unfortunately, the patient refused secondary operative management. Mild neck pain, moderate disability, and fair functional outcome were found in 2 further female falls victims, aged 88 and 90 years, neither of whom achieved osseous fusion after treatment in cervical collars for 16 and 24 weeks, respectively. Both patients achieved fracture stability, however.

Figure 2. Dynamic flexion radiograph at 10 months post injury in the same patient, with presumption of fibrous union.

There were 32 patients treated in halothoracic bracing, including those managed in cervical collars for a period of time after halothoracic removal. Of these, 12 patients (37.5%) achieved osseous fusion, but 100% achieved stability of the fracture site (Table 2). Three patients sustained Type IIA fractures, 2 of which fused and all of which were demonstrated to be stable. The majority of patients reported no pain (n ⫽ 10) or mild pain (n ⫽ 11), and there were no cases of severe pain in the halothoracic group. The Neck Disability Index indicated no disability in 8 patients in this group (25%), mild disability in 20 patients (62.5%), moderate disability in 4 patients (12.5%), and no severe disability. The majority of patients treated in halothoracic bracing were found to have excellent (n ⫽ 6) or good (n ⫽ 21) functional outcomes (Table 2). There were no patients in either treatment group who suffered decreasing neurologic status.

Discussion Odontoid fractures in the elderly population are associated with elevated morbidity and mortality rates.2,5,12,19 As a result, the management of Type II odontoid fracture in such patients remains controversial, with debate surrounding the treatment options of operative fixation versus conservative management using halothoracic bracing and/or cervical collar. The presence of osteopenia, de-

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Figure 3. Dynamic extension radiograph at 10 months post injury in the same patient, with presumption of fibrous union.

generative cervical spine change and comminution of fracture in such patients can result in difficulty in achieving cervical fracture union,7,9,20 while post procedure complication rates vary widely1,12,21,22 and have been reported in more than 50% of cases in some studies.5,23 Table 2. Comparison of Clinical and Functional Outcomes in Conservative Type II Odontoid Fracture Management

Osseous fusion Stability Pain level No pain Mild pain Moderate pain Moderate/severe pain Severe pain Neck disability* No disability Mild disability Moderate disability Moderate/severe disability Severe disability Functional outcome† Excellent Good Fair Poor

Cervical Collar (n ⫽ 10)

Halothoracic Brace (n ⫽ 32)

Total (n ⫽ 42)

5 (50%) 9 (90%)

12 (38%) 32 (100%)

40.5% 97.6%

2 (20%) 3 (30%) 4 (40%) 0 (0%) 1 (10%)

10 (31.2%) 11 (34.3%) 8 (25.0%) 3 (9.4%) 0 (0%)

28.6% 33.3% 28.6% 7.1% 2.4%

1 (10%) 8 (80%) 0 (0%) 0 (0%) 1 (10%)

8 (25.0%) 20 (62.5%) 4 (12.5%) 0 (0%) 0 (0%)

21.4% 66.6% 9.5% 0.0% 2.4%

1 (10%) 6 (60%) 2 (20%) 1 (10%)

6 (18.8%) 21 (65.6%) 5 (15.6%) 0 (0%)

16.6% 64.3% 16.6% 2.4%

*Derived from the Neck Disability Index.15 †Derived from a modification of the Smiley-Webster Scale.16,17

The utilization of cervical collars alone for nondisplaced Type II odontoid fractures is a subject of debate, with the fracture union rates generally reported as the primary outcome measure. Union rates of 50% to 80% have been reported.5,12,24 Muller et al5 found that loss of reduction occurred in 45% of elderly patients treated in Philadelphia collars, and Seybold et al17 reported a higher complication rate with cervical collars compared with halothoracic bracing. Additionally, the ability to restrict flexion, extension, and lateral bending at the atlantoaxial junction is limited in cervical collars in comparison with halothoracic bracing,25 which may explain the propensity to elevated proportions of loss of reduction in collars. In our study, the fracture union rate was greater when treatment included cervical collar alone compared with halothoracic bracing (50% vs. 37.5%) but resultant stability was comparable (90% vs. 100%). However, greater levels of residual neck pain and poorer functional outcomes resulted in the group treated in cervical collars alone. Conservative management has been associated with complications such as nonunion, halothoracic pinsite infections, decrease in pin tension, halothoracic vest and cervical collar-related pressure ulcers, respiratory compromise,6,26,27 and cerebral abscess.28 Many complications, however, particularly those of pressure ulceration and respiratory issues, have been attributed to inactivity and bed rest rather than choice of device.12,22 Halothoracic and cervical collar-specific complications may be avoided by improved attention to pinsite care, frequent observation/maintenance of the device, and early mobilization.2,12,26 Our institutional protocol, including daily pinsite dressings, frequent inspection of halothoracic devices by qualified orthotics staff, 4 to 8 hourly cervical collar care, and early mobilization may have contributed to our modest complication rates after conservative management of Type II odontoid fractures in older patients. The relationship between patient age and fusion rates in Type II fractures has been explored in several studies, but results are inconclusive. Some studies have reported that older patients were at increased risk of treatment failure when managed in halothoracic bracing.23,29,30 However, other studies have reported age to be statistically insignificant in fracture healing in this group.1,3,17,22 The rationale of advanced age and elevated nonunion rates in conservative management, however, has led to a trend towards operative fixation of Type II odontoid fractures, with osseous union as the principal aim of management. Bone healing rates after primary instrumental stabilization have been reported to be as high as 80% to 96%,8,31 which may be falsely elevated due to the frequent utilization of halothoracic bracing or cervical collar after surgery. Nevertheless, adequate anterior screw fixation may be precluded by osteopenia in the elderly,32 and has been associated with significant operative technical difficulty,20 nonunion, posterior fracture displacement, and respiratory complications.32 Potential complications in posterior fixation include secondary spinal cord or ver-

Type II Odontoid Fractures • Koech et al 2885

tebral artery injury.9,33 Additionally, the comorbidities often present in elderly patients serve to increase anesthetic risk.34 There also seems to be a lack of discernable difference in final functional status, including level of residual pain, between halothoracic and operative management for Type II odontoid fractures.17 As a result, at our institution, operative fixation is generally reserved for cases where gross instability is initially detected, or when conservative management has been ineffective. Reported fracture union rates after conservative management of Type II fractures vary widely from 23% to 82%.2,7,13,30,35–37 Many clinicians advocate radiographic bone union as the primary indicator of success of treatment of odontoid fractures. In fact, Bohler8 suggests that anatomic fracture healing with favorable functional outcome should constitute the aim of management and that osseous nonunion is an “absolute indication” for secondary surgical fixation. However, the definitive association of radiographic union with optimal functional outcome has not been proven,36 and several studies have demonstrated that adequate stability can be achieved in the setting of fibrous union, rather than bony union.12,13,36 Stoney et al30 found an osseous union rate of 82% overall, and 73% in elderly patients, in a study of 22 patients of varying age who were treated in halothoracic bracing. None of the patients with nonunion developed secondary neurologic deficit, and the authors suggest that fibrous union, allowed to develop as a result of prolonged external immobilization, may provide adequate strength at the fracture site to prevent abnormal neurology. Ryan and Taylor13 reported an osseous union rate of 23% in a study of 35 patients aged ⬎60 years and concluded that diagnostic delays and lack of adequate immobilization contributed to the poor union rate. Neurologic status on admission was deemed the primary determinant of functional outcome, rather than fracture healing status.13 Our union rates of 50% for treatment in cervical collar and 37.5% for halothoracic bracing were associated with high rates of fracture stability and favorable clinical and functional outcomes. Stable, fibrous union may be an adequate aim of treatment in elderly patients,12,13 thereby reducing the necessity for operative management in a group with such predisposition to increased morbidity and mortality. Despite our study representing one of the largest groups of elderly patients with odontoid fracture, several limitations were evident. Lack of randomization of patients to treatment in cervical collar or halothoracic brace, although baseline demographics were similar, may have resulted in an underestimation of the differences in treatment outcomes. As undisplaced fractures were generally treated in cervical collars and displaced fractures in halothoracic bracing, surgeon preference may therefore have influenced outcomes. Secondly, the small sample size may serve to reduce the power of the study. However, odontoid fracture in this population occurs rarely, with a prevalence of 0.08% at our Level 1 trauma center, and this study is one of the largest to date.

Thirdly, the entire elderly odontoid fracture population was not available for follow-up review. This loss to follow-up is common in the elderly age group due to potential increase in frailty and underlying medical condition. However, those presenting for review were representative of the elderly trauma population at our institution. Unfortunately, Class III data forms the basis for the majority of published information pertaining to the effectiveness of the management of Type II fractures in elderly patients. Additionally, very few studies have compared conservative or operative management and fracture union with long-term clinical and functional outcomes, a randomized, controlled trial may contribute to the clarification of the most appropriate treatment option to attain of the best outcomes with the lowest associated risk in elderly patients. Conclusion Halothoracic bracing as a management option for elderly patients with Type II odontoid fracture results in improved clinical and functional outcome when compared with primary treatment in a cervical collar. Adequate fracture stability is achievable in the setting of fibrous union, to the extent that assessment of stability may be more appropriate as the primary indication of treatment success than osseous union. The adoption of stability as the most pertinent outcome measure may reduce the requirement for secondary operative stabilization and its associated risks in the elderly population. Key Points ● The main aim of Type II odontoid fracture management in elderly patients has tended towards the achievement of osseous fusion. ● Fracture stability can be achieved, however, in the setting of fibrous union. ● Long-term outcomes appear more favorable in patients who have been treated in halothoracic bracing in preference to cervical collars. ● Nonoperative management results in fracture stability in most patients. ● Type II odontoid fracture stability, rather than osseous fusion, may be an adequate treatment goal in the elderly patient population.

Acknowledgment The authors gratefully acknowledge the assistance of Phil Lewis, Database Manager, Department of Neurosurgery, for assistance with retrieval of data.

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