Fractures of Cervical Spine: Classification, Symptoms, and Treatment

Fractures of the cervical spine are serious injuries that require thorough diagnosis and treatment. Injuries to the upper cervical spine — specifically the first (C1, atlas) and second (C2, axis) vertebrae — require even more caution as they provide head mobility and lie in close proximity to the brainstem and spinal cord.

Fracture of First Cervical Vertebra

The first cervical vertebra (C1, atlas) supports the skull and contributes to head movement. A fracture typically compromises the ring‑shaped structure of the vertebra. C1 fractures are clinically significant due to their proximity to the spinal cord and brainstem, creating a risk of neurological deficits or life‑threatening instability.

Etiology

C1 fractures are primarily associated with trauma.

• High‑energy injuries: road traffic accidents, falls from height, or sports injuries (i.e., diving into shallow water).
• Low‑energy injuries: in older adults (for example, a fall from standing height) due to metabolic bone disorders such as osteoporosis.
• Rare causes: pathologic fractures due to tumors or infections.

Mechanism of Injury

The classic mechanism is axial loading, in which force compresses the skull and transmits energy to the atlas (C1), causing structural failure. Hyperextension or hyperflexion may aggravate the condition.

Epidemiology

C1 fractures account for 2–13 % of cervical spine injuries and 1–3 % of all spinal injuries. Men aged 20–40 years are more prone to such fractures (75 % of cases) due to high‑risk activities. A secondary peak occurs in older adults (> 65 years) with osteoporosis.

Mortality rates are low (4–10 %), but associated injuries (for example, C2 fractures) are observed in 30–50 % of cases.

Classification of C1 Fractures

Gehweiler and Dickman Classification

The Gehweiler classification describes five types of C1 fractures based on involvement of specific anatomical structures. The Dickman classification of injuries to the transverse atlantal ligament is also integrated into this system.

Gehweiler Classification with Dickman Modifications

Landells Classification

Similar to the Gehweiler system, the Landells classification identifies three types of fractures:

1. Type I: Fracture confined to either the anterior or posterior arch.
2. Type II: Fracture of both arches.
3. Type III: Fracture of the lateral mass (extending into one arch only).

3D Models of C1 Fractures

C1 fracture, Type 1 (Gehweiler)

C1 fracture, Type 2 (Gehweiler)

C1 fracture, Type 3a (Gehweiler)

C1 fracture, Type 3b, Dickman Type 1 (Gehweiler)

C1 fracture, Type 3b, Dickman Type 2 (Gehweiler)

C1 fracture, Type 4 (Gehweiler)

C1 fracture, Type 5 (Gehweiler)

Clinical Manifestations

Symptoms range from mild to severe.

• Stable fractures: localized neck pain, stiffness, and muscle spasm.
• Unstable fractures: possible neurological deficits (limb weakness, impaired respiration) due to compression of the spinal cord or brainstem.
• Vertebral artery injury (blunt cerebrovascular injury, BCVI): may present with dizziness (vertigo), double vision (diplopia), vision loss, uncoordinated movements (ataxia), difficulty swallowing (dysphagia), or vomiting.
• Asymptomatic cases: may occur in some patients and complicate diagnosis.

Diagnosis of C1 Fracture

Diagnosis is based on clinical evaluation and radiologic imaging.

Clinical Evaluation

In general, neck pain and restricted motion are the primary symptoms of cervical spine injuries. During the neurological examination, motor and sensory deficits are assessed. With isolated C1 injuries, neurological deficits are less likely; however, C2 fractures are associated with a significantly higher risk of neurological complications.

Radiologic Methods:

1. CT (computed tomography): the gold standard for detecting fracture lines and displacement.
2. Radiography: an open‑mouth anteroposterior view may demonstrate lateral displacement of the lateral masses (displacement greater than 7 mm suggests a Jefferson fracture).
3. MRI (magnetic resonance imaging): allows evaluation of ligamentous injury and spinal cord compression.

During evaluation of a C1 injury, possible developmental anomalies of the atlas should be considered. A split or bipartite atlas is a rare congenital anomaly in which the atlas is divided into two halves by fusion defects in both the anterior and posterior arches. The bony defects are covered by fibrous tissue. The defects in both cases are located along the midline; however, the anomaly of the anterior arch is typically smaller than the defect of the posterior arch. A bipartite atlas is asymptomatic and usually identified incidentally on imaging.

Treatment of C1 Fractures

Medical Therapy

Indications: stable fractures (intact transverse ligament, no displacement).

Procedure:

• Immobilization: rigid cervical collar (e.g., Miami J) or a halo-gravity traction device (HGTD) for 8–12 weeks.
• Dynamic radiographic monitoring: serial imaging assists with alignment and fracture healing.
• Rehabilitation: physical therapy after immobilization to restore mobility and muscle tone.

Surgical Therapy

Indications: segmental instability (transverse ligament rupture, displacement > 7 mm), neurological deficits, or failure of medical therapy. The goal is to prevent spinal cord injury and restore spinal alignment.

Procedure:

• Occipitocervical fusion: stabilizes the skull and cervical spine. Typically performed in combined C1 and C2 injuries.
• C1–C2 fusion: preserves some neck motion while fixing the atlas to the axis.

Fracture of Second Cervical Vertebra

The second cervical vertebra (C2, axis) plays a key role in supporting the skull, enabling head rotation, and protecting the upper spinal cord. Fractures in this region range from minor nondisplaced cracks to severe, unstable injuries that endanger the spinal cord and vital functions.

Etiology

C2 fractures may result from various traumatic mechanisms:

1. Direct trauma: the most common cause, often due to high‑impact injuries.
2. Road traffic accidents: both high‑speed impacts and lower‑energy mechanisms such as abrupt deceleration.
3. Sports injuries: contact sports, diving accidents, and equestrian activities.
4. Pathologic conditions: metastatic lesions of C2 and chronic metabolic disorders affecting bone density, contributing to low‑energy fractures.

Mechanism of Injury

Because of its unique anatomical structure, С2 is susceptible to characteristic injury patterns and fracture types:

1. Hyperextension: a sudden backward movement of the head (for example, a rear‑impact collision) may cause a “hangman’s fracture” — a bilateral fracture of the pars interarticularis.
2. Axial loading: vertical force applied to the head (for example, diving into shallow water) may result in fractures of the odontoid process (dens axis).
3. Flexion‑rotation: twisting forces may also produce fractures of the odontoid process or the lateral mass.
4. Direct trauma: blows to the upper neck or viscerocranium may lead to C2 fractures.

Epidemiology

1. C2 fractures account for 20 % of all cervical spine fractures.
2. Odontoid (dens) fractures are the most common (50–75 %), particularly in older adults after falls from standing height.
3. Hangman’s fractures (traumatic spondylolisthesis of the axis) are the second most common C2 fracture type and are frequently associated with road traffic accidents and falls.

They tend to be more common in men involved in athletic activities or occupations with higher injury risk (construction, etc.).

Classification of С2 Fractures

Multiple classification systems exist for C2 fractures. Historically, the most significant systems are based on the anatomical region involved. For example, Schatzker classified fractures according to their position relative to accessory ligaments.

Classification of Odontoid Fractures (Anderson & D’Alonzo)

The most widely used classification for odontoid fractures is based on the position and location of the fracture.

Anderson and D’Alonzo Classification with Handley Modification*

*The Hadley subclassification identifies the comminuted variant of Type II fractures. This subtype carries a significantly increased risk of nonunion with medical therapy. Occurs in 5–10 % of all Type II fractures.

3D Models of Odontoid (C2) Fractures:

Odontoid fracture, Type I (Anderson and D’Alonzo)

Odontoid fracture, Type II (Anderson and D’Alonzo)

Odontoid fracture, Type IIa (Anderson and D’Alonzo, Hadley modification)

Odontoid fracture, Type III (Anderson and D’Alonzo)

Grauer classification is a more detailed system for Type II odontoid fractures (subtypes A, B, C), based on the shape and direction of the fracture line, guiding treatment strategy.

The Roy — Camille classification does not adequately describe the direction of fragment displacement or the course of the fracture line.

An embryologic classification has also been developed based on the embryologic fusion centers of the odontoid process. While Type I involves the upper quarter of the dens, Type II affects its lower three quarters.

Classification of Hangman’s Fractures (Levine & Edwards)

This system was developed for fractures of the pars interarticularis of C2 (traumatic spondylolisthesis of the axis, hangman’s fracture) based on the mechanism of injury.

Levine and Edwards Classification

Clinical Manifestations

1. Severe neck pain: localized to the upper cervical spine, worsened by movement.
2. Reduced range of motion in the neck.
3. Occipital headache: may occur due to referred pain.
4. Neurological symptoms: rare, but may include numbness, weakness, or even quadriplegia in severe injuries.
5. Difficulty breathing and swallowing: may occur in cases of a large retropharyngeal hematoma.

Diagnosis

Diagnosis is based on clinical evaluation and radiologic imaging.

Clinical Evaluation:

1. Medical history: recent neck trauma, mechanism of injury, neurological symptoms.
2. Physical examination: neck pain, tenderness on palpation, restricted motion, and possible neurological deficits including limb weakness, numbness, or respiratory impairment.

Radiologic Methods:

1. Radiography: standard anteroposterior, lateral, and open‑mouth odontoid views (the latter being more reliable) help identify odontoid fractures. Functional radiographs (flexion and extension): required to assess atlanto‑occipital instability.
2. CT (computed tomography): the gold standard; provides detailed visualization of fracture morphology and displacement.
3. MRI (magnetic resonance imaging): indicated when neurological deficits are present.

Treatment of C2 Fractures

Medical Therapy

Indications: nondisplaced fractures, no spinal cord compression and no progressive neurological symptoms. Also indicated for patients who cannot undergo surgery.

Procedure:

1. Rigid cervical collar: commonly used for nondisplaced Type I and Type III odontoid fractures, as well as Type I traumatic spondylolisthesis.
2. HGTD immobilization: provides maximal external stabilization; typically required for some Type II odontoid fractures and certain traumatic spondylolistheses.

Many C2 fractures can be managed conservatively, especially when stable and without neurological deficits. Most patients recover with appropriate immobilization: external brace or HGTDs achieve 100 % union in Type I fractures and 85–100 % union in Type III fractures. In Type II fractures, union rates reach 57 %, but this rate decreases significantly in older adults.

Surgical Therapy

Indications: instability, displacement, nonunion, neurological deficit, or multiple injuries.

Procedure:

1. Anterior odontoid screw fixation: internal fixation for displaced Type II odontoid fractures, especially in younger patients. Union is achieved in approximately 90 % of cases.
2. Posterior C1–C2 fusion: indicated for unstable, comminuted fractures or failed medical therapy. Fusion rates are high, although the preferred surgical technique plays a significant role.

Surgical intervention often provides excellent stabilization and neurological outcomes but carries operative risks and requires longer rehabilitation.

Prognosis and Outcomes

Key prognostic factors for C1 and C2 fractures include integrity of the ligamentous structures, degree of displacement and angulation, timing and effectiveness of stabilization, and bone quality. Structured and consistent rehabilitation also plays an important role in overall recovery.

Prognosis in C1 Fracture

• Isolated fracture of the anterior arch: favorable due to stability and rare neurological complications.
• Isolated fracture of the posterior arch: similar prognosis; the fracture is stable, and neurological complications are extremely rare.
• Одновременное повреждение передней и задней дуг: прогностически менее благоприятен и зависит от целостности поперечной связки. 
  • With an intact transverse ligament (Gehweiler Type IIIA), the fracture is relatively stable and the prognosis is relatively favorable.
  • With any form of transverse ligament injury, there is a risk of chronic instability and reduced cervical range of motion after fracture healing.
• Fracture of the lateral mass: prognosis also depends on ligamentous involvement. With an intact transverse ligament and stable immobilization, the prognosis is favorable. With ligamentous injury, there is a risk of segmental instability, sometimes requiring spinal fusion.
• Isolated fracture of the transverse process: favorable prognosis, but evaluation of nearby vascular structures is required.

Prognosis in C2 Fracture

• Fractures of the odontoid process tip: favorable prognosis due to high union rates, fracture stability, and rare neurological complications.
• Fracture of the odontoid process base: associated with a high risk of nonunion due to anatomical features of the blood supply, reaching 50 % with medical therapy. Malunion and chronic pain syndrome are possible. Thus, the prognosis for odontoid base fractures is less favorable.
• Type III fractures (Anderson and D’Alonzo): good prognosis because the fracture line passes through well‑vascularized cancellous bone of the vertebral body and is more stable than Type II fractures. Union is achieved in 85–90 % of cases.
• Prognosis for traumatic spondylolisthesis (hangman’s fracture) depends on fracture morphology, i.e., stability. Stable fractures have a favorable prognosis. Unstable fractures require surgical treatment, increasing the risk of complications. Neurological complications are rare because the spinal canal widens in this injury pattern. Union is achieved in approximately 90 % of cases. Chronic pain syndrome typically develops with misdiagnosis, delayed treatment, or nonunion.

Rehabilitation Protocol

Rehabilitation is a key stage of treatment. It is divided into phases depending on fracture stability.

If new neurological symptoms appear during rehabilitation, existing symptoms worsen, body temperature rises above normal, or breathing/swallowing becomes difficult, immediate medical evaluation is required.

Rehabilitation After C1 Fracture

For Stable Fractures (Medical Therapy):

• Phase 1 — Immobilization (0–6 weeks): Stable fixation (brace/HGTD). Cervical loading and movement are strictly limited. Isometric exercises in healthy segments and extremities, as well as breathing exercises, are permitted.
• Phase 2 — Early Mobilization (6–12 weeks): Initiated after radiographic confirmation of fracture consolidation. Exercises aimed at restoring range of motion and strength. Load and movement volume should increase gradually, as tolerated. It is advisable to begin with flexion‑extension movements, followed by rotational and lateral bending exercises.
• Phase 3 — Functional Recovery (12+ weeks): Return to unrestricted daily activities. Contact sports and high‑impact axial loading should be avoided. Cardiovascular training, swimming, range‑of‑motion exercises, and progressive strengthening of cervical and upper thoracic muscles are acceptable.

If neurological symptoms appear or recur, or if fracture consolidation is delayed, the duration of each phase is determined at physician’s discretion.

Rehabilitation After Unstable Fractures (Postoperative Period):

• 0–6 weeks: Protection with a device (brace/HGTD). Breathing exercises, bed mobility training, and gait training under immobilization are indicated.
• 6–12+ months: Return to work, progressive physical loading, and practice of task‑specific skills.
• 6–12 weeks: Protected mobilization; strengthening of the back and limb muscles to enable independent ambulation and daily activities.
• 12–24 weeks: Restoration of range of motion (within the limits permitted by the hardware). Exercises focus on strengthening the core and anterior abdominal wall. Cycling is permitted.

Rehabilitation After C2 Fracture

Rehabilitation Protocol for Stable Fractures

Rehabilitation Protocol for Unstable C2 Fractures Requiring Surgical Treatment

The degree of motion restriction depends on the type of surgical intervention. Fixation of the odontoid process with a screw preserves rotation at the operated segment. By contrast, posterior C1–C2 fusion results in loss of rotation at that level. Occipitocervical fusion leads to significant limitations in segmental mobility.