Odontoid fractures (dens fractures) are fractures of the odontoid process of the C2 vertebra — the most common fracture of the axis and the most common cervical spine fracture in patients over 65 years. [1-2] They represent up to 15% of all cervical fractures and are increasingly prevalent due to the aging population. [1] The Anderson and D'Alonzo classification (Types I, II, III) is the cornerstone for guiding management. [1][3]
1. History
- Mechanism of injury: Low-energy falls (ground-level) in elderly; high-energy trauma (MVCs, sports) in younger patients [1][4]
- Neck pain: Upper cervical/suboccipital pain, often poorly localized
- Timing: Acute onset post-trauma; elderly patients may present days later with vague complaints
- Severity/progression: Ask about worsening pain, new weakness, numbness, or gait instability
- Associated symptoms: Headache, restricted neck rotation, dysphagia (from retropharyngeal swelling)
- Important negatives: Absence of extremity weakness, bowel/bladder dysfunction, paresthesias — most patients will not present with neurological injury [1]
2. Alarm Features
- Neurological deficits: Any motor weakness, sensory loss, or myelopathic signs (hyperreflexia, clonus, Babinski) — present in ~4% at diagnosis [5]
- Central cord syndrome: Especially in elderly with pre-existing canal stenosis
- Signs of atlantoaxial instability: Torticollis, severe restriction of rotation, sensation of head "falling forward"
- Respiratory compromise: High cervical cord compression can affect diaphragmatic innervation (C3-C5)
- Polytrauma: Concomitant C1 fracture occurs in ~9% of upper cervical injuries — always evaluate the entire cervical spine [6]
- Occipitocervical dissociation: Type I odontoid fractures may indicate ligamentous avulsion associated with this potentially fatal injury [1][7]
3. Medications
- Acute pain management: Acetaminophen as first-line; NSAIDs with caution (theoretical concern for bone healing); opioids for severe pain with short-course prescribing
- Anticoagulants/antiplatelets: Document use — increases risk of epidural hematoma and complicates surgical planning
- Bone health optimization: Calcium, vitamin D supplementation; consider bisphosphonates or other osteoporosis treatment after fracture stabilization [2]
- Avoid: Muscle relaxants that may mask neurological deterioration; excessive sedation in elderly
- Perioperative considerations: DVT prophylaxis if immobilized; PPI for stress ulcer prophylaxis if hospitalized
4. Diet
- Dysphagia screening: Retropharyngeal swelling or halo/collar use can impair swallowing — assess before oral intake
- Calcium and vitamin D: Ensure adequate intake (1200 mg calcium, 800–1000 IU vitamin D daily) for bone healing
- Protein: Adequate protein intake supports fracture healing, particularly in malnourished elderly
- Hydration: Maintain hydration, especially in immobilized patients at risk for constipation and UTI
5. Review of Systems
- Neurological: Weakness, numbness, tingling in extremities; gait changes; bowel/bladder dysfunction
- Musculoskeletal: Other sites of pain (concomitant fractures — hip, wrist, thoracolumbar spine)
- Constitutional: Fever, weight loss, night sweats (consider pathologic fracture if no clear trauma)
- Vascular: Symptoms of vertebral artery injury — dizziness, visual changes, posterior circulation stroke symptoms
- Respiratory: Dyspnea (high cord injury, aspiration risk)
6. Collateral History and Family History
- Collateral: Witnessed mechanism, loss of consciousness, ambulatory status pre-injury, baseline functional status (critical for elderly — Barthel Index, frailty assessment) [4][8]
- Pre-injury mobility and independence: Determines treatment goals (bony union vs. stable fibrous nonunion)
- Family history: Osteoporosis, connective tissue disorders
- Social context: Living situation (alone vs. assisted), ability to comply with collar wear, fall risk assessment
7. Risk Factors
- Age >65 years: Single strongest epidemiologic risk factor; odontoid fractures are the majority of cervical fractures in patients >80 [2][6]
- Osteoporosis/osteopenia: Poor bone quality predisposes to fracture and nonunion [1][9]
- Falls: Ground-level falls are the predominant mechanism in elderly [4]
- High-energy trauma: MVCs, diving, contact sports in younger patients
- Pre-existing cervical spondylosis: Stiffened adjacent segments concentrate force at C1-C2
- Smoking: Negatively associated with union (aOR 0.2) [9]
- Frailty: Independently reduces union odds and increases mortality [8-9]
8. Differential Diagnosis
- Hangman's fracture (C2 pars interarticularis fracture): Bilateral pars fracture; different fracture line on CT [1][10]
- C1 (atlas) fracture (Jefferson fracture): Burst fracture of C1 ring; often coexists with odontoid fractures [6][10]
- Atlanto-occipital dissociation: Ligamentous disruption; often fatal; Type I odontoid fracture may be a clue [10]
- Atlantoaxial rotatory subluxation: Torticollis presentation; CT with 3D reconstruction differentiates [11]
- Pathologic fracture: Metastasis, myeloma, or infection involving the dens — suspect if atraumatic or minimal trauma in younger patients
- Os odontoideum: Congenital anomaly mimicking a Type II fracture; smooth, well-corticated margins distinguish it from acute fracture
- Cervical strain/sprain: No fracture on imaging; diagnosis of exclusion
9. Past Medical History
- Osteoporosis: DEXA results, prior fragility fractures
- Prior cervical spine surgery or injury
- Rheumatoid arthritis: Predisposes to atlantoaxial instability and pannus formation around the dens
- Ankylosing spondylitis/DISH: Rigid spine increases fracture risk with minor trauma
- Anticoagulation use: Warfarin, DOACs — bleeding risk
- Comorbidities: CCI (Charlson Comorbidity Index) and ASA class guide surgical risk assessment [12-13]
10. Physical Exam
- Vital signs: Hypotension + bradycardia → neurogenic shock (high cervical cord injury)
- Cervical spine: Midline tenderness at C1-C2 level; palpate for step-off or crepitus (with collar in place — do not remove until cleared)
- Neurological exam:
- Motor: Strength in all extremities (C5-T1 myotomes, lower extremities)
- Sensory: Dermatomal testing, perianal sensation
- Reflexes: Deep tendon reflexes, Babinski, Hoffman sign
- Rectal tone: If spinal cord injury suspected
- Range of motion: Do NOT test active ROM until fracture is excluded or characterized
- Assess for associated injuries: Head laceration, facial fractures, thoracolumbar tenderness
11. Lab Studies
- Routine trauma labs: CBC, BMP, coagulation studies (PT/INR, PTT), type and screen
- If pathologic fracture suspected: ESR, CRP, serum protein electrophoresis, calcium, alkaline phosphatase, PSA
- Preoperative labs: If surgery planned — add hepatic panel, urinalysis
- Bone health: 25-OH vitamin D level; consider DEXA scan during follow-up [2]
- Monitoring: Serial neurological exams are more important than serial labs
12. Imaging
- First-line: CT cervical spine without contrast — reference standard with >98% sensitivity for cervical fractures. Thin-cut (≤3 mm) axial images with sagittal and coronal reformats [7][14]
- Classify the fracture on CT using the Anderson and D'Alonzo system: [1][3]
- Type I: Avulsion of the tip of the dens (above transverse ligament) — usually stable
- Type II: Fracture at the base of the dens (junction with C2 body) — highest risk of nonunion
- Type III: Fracture extends into the C2 vertebral body — generally good healing potential
- MRI cervical spine: Indicated if neurological deficits are present, to evaluate spinal cord injury, ligamentous disruption (transverse ligament), or epidural hematoma. Not routinely needed if CT is negative and patient is neurologically intact [11][14]
- Plain radiographs: Low sensitivity (36%); CT has supplanted radiography for trauma evaluation. Open-mouth odontoid view historically used but insufficient alone [14]
- Key CT findings to document: Fracture type, displacement (mm), angulation (degrees), comminution, direction of displacement (anterior vs. posterior), transverse ligament integrity
13. Special Tests
- Anderson and D'Alonzo Classification: Types I, II, III — guides treatment [1][3]
- Roy-Camille subtypes (for Type II): Based on fracture line obliquity — anterior oblique, posterior oblique, horizontal [1]
- Stability assessment: Displacement >5 mm and angulation >11° define instability [7][15]
- NEXUS criteria / Canadian C-Spine Rule (CCR): Used to determine need for imaging in the ED [14]
- Frailty indices: Modified Frailty Index (mFI-5), Clinical Frailty Scale (CFS) — guide surgical decision-making in elderly [4][8]
- Dynamic fluoroscopy: Rarely used acutely; may help assess instability in subacute/chronic settings [10]
14. ECG
- Indications: Preoperative assessment; elderly patients with cardiac comorbidities
- Bradycardia: May indicate neurogenic shock from high cervical cord injury
- No specific ECG pattern is pathognomonic for odontoid fracture, but cardiac clearance is essential before surgical intervention in the elderly population
15. Assessment
Anderson and D'Alonzo Classification Summary
- Type II fractures are the most common (~55% of odontoid fractures) and the most clinically challenging [4]
- Nonunion risk factors for Type II: Displacement >5 mm, angulation ≥11°, comminution, age ≥80, smoking, osteoporosis, posterior displacement, frailty [7][9][15]
- Complications: Nonunion/fibrous union, atlantoaxial instability, delayed myelopathy, vertebral artery injury, mortality (30-day mortality ~13%; 6-month mortality ~22%) [4][17]
- Most patients present without neurological injury, but mechanical instability can develop [1]
16. Treatment Plan
Initial Stabilization (ED)
- Maintain cervical spine immobilization with rigid collar
- Full trauma assessment (ATLS approach) — evaluate for concomitant injuries
- Neurological assessment and documentation
- Urgent neurosurgery/spine surgery consultation for any neurological deficit or unstable fracture pattern
Type I Fractures
- Cervical collar for 6–8 weeks; generally stable [1][7]
- Rule out occipitocervical dissociation (rare but critical association)
Type II Fractures — management remains controversial [2][7]
- Non-displaced, stable (displacement <5 mm, angulation <11°):
- Age <50: Halo vest immobilization for 8–12 weeks [7]
- Age >75: Rigid cervical collar; fibrous nonunion without instability is an acceptable endpoint [7][12]
- Displaced or unstable (displacement ≥5 mm, angulation ≥11°, comminution):
- Surgical fixation recommended [2][7]
- Anterior odontoid screw: Preserves C1-C2 rotation; requires favorable fracture line orientation (anterior-inferior to posterior-superior obliquity) [1][16]
- Posterior C1-C2 fusion (Harms or Magerl technique): More versatile; applicable to any fracture pattern; sacrifices C1-C2 rotation (~50% of cervical rotation) [1][16]
- Surgery yields higher fusion rates (74% vs. 40%) but more complications (26% vs. 18.5%) and longer LOS (13.6 vs. 8.1 days) compared to nonoperative management [17]
Type III Fractures
- Cervical collar or halo vest for 8–12 weeks [5][7]
- Bony fusion rate ~96% with conservative management [5]
- Surgery reserved for significant displacement or failed conservative treatment
All Patients
- Bone health optimization: Vitamin D, calcium, osteoporosis workup and treatment [2]
- DVT prophylaxis if immobilized
- Pain management: Multimodal approach
The following Kaplan-Meier curve from a systematic review illustrates the survival advantage associated with surgical treatment of Type II odontoid fractures in elderly patients:
17. Disposition
- Admission criteria: [13]
- Any neurological deficit
- Unstable fracture pattern (Type II with displacement/angulation)
- Need for halo application
- Planned surgical intervention
- Elderly patients requiring pain control, fall risk assessment, or medical optimization
- Polytrauma
- Observation: Stable, non-displaced fractures in reliable patients may be observed briefly (24–48 hours) before discharge in a collar
- Discharge criteria:
- Neurologically intact
- Stable fracture pattern (Type I, non-displaced Type III, or stable Type II)
- Adequate pain control
- Able to tolerate and comply with cervical collar
- Reliable follow-up arranged
- Specialist consultation triggers:
- All Type II fractures → spine surgery consultation
- Any neurological deficit → emergent neurosurgery
- Concomitant C1 fracture or ligamentous injury → spine surgery
- Pathologic fracture → oncology
18. Follow Up / Return Precautions
- Follow-up timing:
- First follow-up at 2 weeks with repeat imaging (CT or radiographs) to assess alignment [7][15]
- Subsequent imaging at 6 weeks, 3 months, and 6 months to monitor for union or nonunion [4][15]
- Return precautions — seek immediate care for:
- New or worsening weakness, numbness, or tingling in arms/legs
- Loss of bowel or bladder control
- Difficulty breathing
- Worsening neck pain despite treatment
- Difficulty swallowing
- Collar-related skin breakdown
- Patient counseling:
- Collar must be worn at all times (including sleep) unless otherwise instructed
- Avoid flexion/extension/rotation of the neck
- Fall prevention measures (especially elderly)
- Expected recovery: 8–12 weeks for most fractures; Type II may take longer or result in stable fibrous nonunion [12]
- Expected outcomes: 95% of elderly patients with Type II fractures managed conservatively achieve excellent functional outcomes within 6 weeks, regardless of bony fusion. Overall 6-month survival is approximately 78% in elderly cohorts. [4][12]
References
1. Odontoid Fractures: A Review of the Current State of the Art. — Nouri A, Da Broi M, May A, et al. Journal of Clinical Medicine. 2024.
2. Management of Odontoid Fractures in the Elderly: A Review of the Literature and an Evidence-Based Treatment Algorithm. — Iyer S, Hurlbert RJ, Albert TJ. Neurosurgery. 2018.
3. Odontoid Fractures: A Standard Review of Current Concepts and Treatment Recommendations. — Nourbakhsh A, Hanson ZC. The Journal of the American Academy of Orthopaedic Surgeons. 2022.
4. Traumatic Odontoid Fracture - Proposal of a Treatment Algorithm. — Rizvi SAM, Linnerud H, Rønning PA, et al. Clinical Neurology and Neurosurgery. 2025.
5. Favorable Prognosis With Nonsurgical Management of Type III Acute Odontoid Fractures: A Consecutive Series of 212 Patients. — Rizvi SAM, Helseth E, Aarhus M, et al. The Spine Journal : Official Journal of the North American Spine Society. 2021.
6. The Epidemiology of Fractures and Fracture-Dislocations of the Cervical Spine. — Ryan MD, Henderson JJ. Injury. 1992.
7. Best Practices Guidelines Spine Injury. — Gregory D. Schroeder MD, Alexander R. Vaccaro MD PhD MBA, William C. Welch MD FACS FAANS FICS FAANOS, et al American College of Surgeons (2022). 2022.
8. The Economics of Surgical Decision-Making in Geriatric Type II Odontoid Fractures: Reframing the Role of Frailty. — Lozano CS, Karthikeyan V, Shakil H, et al. Neurosurgery. 2025.
9. Comparative Effectiveness of Conservative Management Versus Surgical Fixation in Acute Type II Odontoid Fractures. — Yazdanian F, Enriquez-Marulanda A, Ramirez-Velandia F, et al. Neurosurgery. 2025.
10. Upper Cervical Spine Trauma. — Bransford RJ, Alton TB, Patel AR, Bellabarba C. The Journal of the American Academy of Orthopaedic Surgeons. 2014.
11. Imaging of Atlanto-Occipital and Atlantoaxial Traumatic Injuries: What the Radiologist Needs to Know. — Riascos R, Bonfante E, Cotes C, et al. Radiographics : A Review Publication of the Radiological Society of North America, Inc. 2015.
12. Odontoid Type II Fractures in Elderly: What Are the Real Management Goals and How to Best Achieve Them? A Multicenter European Study on Functional Outcome. — Chibbaro S, Mallereau CH, Ganau M, et al. Neurosurgical Review. 2022.
13. Multicenter Retrospective Cohort Study of the Association Between Surgery for Odontoid Fractures in the Elderly and in-Hospital Outcomes. — Merali Z, Zhang PF, Jaffe RH, et al. Scientific Reports. 2023.
14. ACR Appropriateness Criteria® Acute Spinal Trauma: 2024 Update. — Hassankhani A, Freeman CW, Banks J, et al. Journal of the American College of Radiology : JACR. 2025.
15. Reevaluation of a Classification System: Stable and Unstable Odontoid Fractures in Geriatric Patients-a Radiological Outcome Measurement. — Deluca A, Wichlas F, Deininger C, Traweger A, Mueller EJ. European Journal of Trauma and Emergency Surgery : Official Publication of the European Trauma Society. 2022.
16. Surgical Versus Conservative Management for Odontoid Fractures. — Shears E, Armitstead CP. The Cochrane Database of Systematic Reviews. 2008.
17. Nonoperative Versus Operative Management of Type II Odontoid Fracture in Older Adults: A Systematic Review and Meta-Analysis. — Avila MJ, Farber SH, Rabah NM, et al. Journal of Neurosurgery. Spine. 2024.
18. Systematic Review on Surgical and Nonsurgical Treatment of Type II Odontoid Fractures in the Elderly. — Robinson Y, Robinson AL, Olerud C. BioMed Research International. 2013.