Management of Subaxial Spine Fractures—insights from the AO Spine Clinical Practice Recommendations

In our review of four impactful studies selected by the AO Spine Knowledge Forum Trauma & Infection group, we focused on evidence that can immediately influence clinical decision-making. Rather than creating rigid treatment algorithms, our goal was to identify findings that help surgeons make better-informed decisions at critical points in patient care. The complete findings are part of the AO Spine Clinical Practice Recommendations series published in the Global Spine Journal.

Imaging remains the foundation of decision-making

For most spine surgeons, the first major decision takes place before treatment planning even begins. The quality of imaging directly influences fracture recognition, assessment of stability, and identification of neurological risk. 

The study by Rutsch and colleagues reinforces what many of us have already experienced in clinical practice. Plain radiographs continue to miss a substantial number of clinically relevant cervical injuries, particularly when compared with modern cross-sectional imaging. CT demonstrated high sensitivity and specificity for detecting cervical trauma, while MRI provided critical additional information when neurological deficits were present despite normal CT findings.

What I find particularly useful is the confirmation that MRI can identify injuries that may fundamentally change treatment plans. In the reviewed study, several patients with initially negative CT scans were subsequently found to have significant pathology on MRI, including injuries requiring surgery. For surgeons managing trauma patients, this serves as a reminder that imaging should always be interpreted within the clinical context.

The practical message is straightforward. CT should be considered the primary imaging modality for suspected cervical trauma, while MRI remains essential when neurological symptoms cannot be explained by CT findings alone. The recommendation against relying on plain radiographs as the sole diagnostic tool reflects current realities in trauma care.

Predicting failure of conservative management

One of the more challenging scenarios involves isolated unilateral facet fractures. Many of these injuries appear stable initially, particularly in neurologically intact patients. However, we have all encountered cases that progress to instability despite appropriate immobilization. 

The systematic review by Cirillo and colleagues provides valuable guidance by identifying fracture characteristics associated with nonoperative treatment failure. The strongest signal emerged from floating lateral mass fractures, corresponding to F3 injuries within the AO Spine Subaxial Cervical Spine Injury Classification System. These fractures demonstrated substantially higher odds of treatment failure compared with less complex facet injuries.

Fragment size also emerged as an important factor. Larger fracture fragments, particularly those involving a significant portion of the lateral mass, were associated with worse outcomes when managed conservatively.

These findings are clinically relevant because they help move decision-making beyond subjective assessments of stability. While surgeon judgment remains essential, identifying objective risk factors provides additional confidence when recommending surgery to patients who might otherwise appear suitable for conservative care.

In our view, the study reinforces a principle many experienced trauma surgeons already follow: not all isolated facet fractures behave the same way. A careful review of CT imaging, with attention to fragment morphology and lateral mass involvement, can help identify patients who are likely to benefit from earlier surgical stabilization.

When should we consider 360° stabilization?

Choosing between anterior-only fixation and combined approaches remains a common challenge in subaxial cervical trauma. 

Anterior cervical discectomy and fusion (ACDF) offers several advantages, including direct decompression, restoration of alignment, and lower soft-tissue morbidity compared with more extensive procedures. However, anterior constructs are not equally effective across all injury patterns.

The study by Singh and colleagues examined factors associated with failure after stand-alone ACDF. Although construct failure was relatively uncommon, the study identified several characteristics that significantly increased the likelihood of requiring secondary posterior fixation.

Posterior longitudinal ligament (PLL) injury emerged as a major predictor. Bilateral facet joint dislocation also significantly increased the risk of anterior construct failure. Age was another important factor, particularly among patients older than 60 years.

These findings are important because they address a question that many surgeons face routinely: should posterior stabilization be performed during the index operation or reserved for revision surgery if failure occurs?

While no single variable should dictate treatment in isolation, the cumulative evidence supports a lower threshold for posterior supplementation in patients with extensive ligamentous disruption, bilateral facet dislocations, or advanced age. These characteristics may indicate instability beyond what an anterior construct alone can reliably control.

The implications are practical. Identifying these risk factors before surgery allows surgeons to avoid staged procedures, reduce construct failure rates, and potentially shorten the overall recovery process for patients.

Selecting the optimal surgical approach

Few topics generate more discussion among spine surgeons than the choice between anterior and posterior approaches.

Kwon and colleagues addressed this question through a randomized trial comparing anterior and posterior fixation for unilateral cervical facet injuries without spinal cord injury. Although the study was modest in size, it remains one of the highest-quality investigations available for this clinical problem.
Several findings favored anterior surgery. Patients in the anterior group experienced lower infection rates, tended toward less postoperative pain, and achieved excellent fusion outcomes. Radiographic alignment was also superior following anterior fixation.

Importantly, long-term functional outcomes were similar between groups, suggesting that both approaches can achieve acceptable clinical results when appropriately selected.

The recommendation favoring anterior fixation for unilateral facet injuries without spinal cord injury should be interpreted as guidance rather than an absolute rule. Patient-specific factors remain critical. Elderly patients, individuals with poor bone quality, or those with associated endplate injuries may still benefit from posterior or combined stabilization strategies.

The study highlights an important principle: surgical approach selection should be driven by injury morphology rather than surgeon habit alone. Matching the fixation strategy to the specific injury pattern remains the key determinant of success.

Moving from evidence to everyday practice

Perhaps the most important contribution of these recommendations is their focus on decision points that all spine surgeons encounter regularly. The recommendations support several practical takeaways:

• CT and MRI should form the cornerstone of cervical trauma imaging.
• Floating lateral mass fractures and large facet fragments deserve heightened attention because of their increased risk of conservative treatment failure.
• Patients older than 60 years, those with PLL disruption, and those with bilateral facet dislocations should prompt serious consideration of posterior stabilization in addition to anterior surgery.
• Anterior fixation appears to offer advantages for selected unilateral facet injuries without spinal cord injury, although patient selection remains essential.

Taken together, these studies help narrow several of the most important evidence gaps in subaxial cervical trauma. They do not eliminate the need for clinical judgment, but they provide surgeons with stronger data to support treatment decisions.

As a specialty, we still need prospective multicenter research capable of validating these recommendations across broader patient populations. Until then, integrating the best available evidence into our daily practice remains the most effective way to improve outcomes for patients with cervical spine trauma.