Anterior Fixation of Floating Facet Fractures in the Cervical Spine: A Prospective Case Series and Biomechanical Analysis

Assessing Treatment of Floating Lateral Mass (FLM) Fractures of the Subaxial Cervical Spine

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

The purpose of the study was to evaluate differences across surgical approaches (anterior, posterior, or combined anterior-posterior) in terms of outcomes following treatment for floating lateral mass (FLM) fractures. Furthermore, we sought to determine whether operative approach to FLM fracture treatment remains superior to nonoperative treatment in terms of clinical outcomes.

BACKGROUND DATA

FLM fractures of the subaxial cervical spine involves separation of the lateral mass from the vertebrae via a disruption of both the lamina and pedicle, resulting in a disconnection of the superior and inferior articular processes. This subset of cervical spine fractures is highly unstable, making proper treatment selection of great importance.

METHODS

In this single-center, retrospective study, we identified patients meeting the definition of an FLM fracture. Radiological imaging from the date of injury was reviewed to ensure presence this injury pattern. Treatment course was assessed to determine nonoperative versus operative treatment. Operative treatment was divided into patients who underwent anterior, posterior, or combined anterior-posterior spinal fusion. We then reviewed postoperative complications among each of the subgroups.

RESULTS

Forty-five patients were determined to have a FLM fracture over a 10-year span. The nonoperative group had n=25, and evidently, there were no patients that crossed over to surgery due to subluxation of the cervical spine after nonoperative treatment. The operative treatment group had n=20, and consisted of 6 anterior, 12 posterior, and 2 combined approaches. Complications appeared in posterior and combined groups. Two hardware failures were noted in the posterior group, along with two postoperative respiratory complications in the combined group. No complications were observed for the anterior group.

CONCLUSIONS

None of the nonoperative patients in this study required further operation or management of their injury, indicating nonoperative treatment as a potentially satisfactory management for appropriately selected FLM fractures.

Which traumatic spinal injury creates which degree of instability? A systematic quantitative review

BACKGROUND CONTEXT

Traumatic spinal injuries often require surgical fixation. Specific three-dimensional degrees of instability after spinal injury, which represent criteria for optimum treatment concepts, however, are still not well investigated.

PURPOSE

The aim of this review therefore was to summarize and quantify multiplanar instability increases due to spinal injury from experimental studies.

STUDY DESIGN/SETTING

Systematic review.

METHODS

A systematic review of the literature was performed using keyword-based search on PubMed and Web of Science databases in order to detect all in vitro studies investigating the destabilizing effect of simulated and provoked traumatic injury in human spine specimens. Together with the experimental designs, the instability parameters range of motion, neutral zone and translation were extracted from the studies and evaluated regarding type and level of injury.

RESULTS

A total of 59 studies was included in this review, of which 43 studies investigated the effect of cervical spine injury. Range of motion increase, which was reported in 58 studies, was generally lower compared to the neutral zone increase, given in 37 studies, despite of injury type and level. Instability increases were highest in flexion/extension for most injury types, while axial rotation was predominantly affected after cervical unilateral dislocation injury and lateral bending solely after odontoid fracture. Whiplash injuries and wedge fractures were found to increase instability equally in all motion planes.

CONCLUSIONS

Specific traumatic spinal injuries produce characteristic but complex three-dimensional degrees of instability, which depend on the type, level, and morphology of the injury. Future studies should expand research on the cervicothoracic, thoracic, and lumbosacral spine and should additionally investigate the destabilizing effects of the injury morphology as well as concomitant rib cage injuries in case of thoracic spinal injuries. Moreover, neutral zone and translation should be measured in addition to the range of motion, while mechanical injury simulation should be preferred to resection or transection of structures to ensure high comparability with the clinical situation.

Variation in global treatment for subaxial cervical spine isolated unilateral facet fractures

PURPOSE

To determine the variation in the global treatment practices for subaxial unilateral cervical spine facet fractures based on surgeon experience, practice setting, and surgical subspecialty.

METHODS

A survey was sent to 272 members of the AO Spine Subaxial Injury Classification System Validation Group worldwide. Questions surveyed surgeon preferences with regard to diagnostic work-up and treatment of fracture types F1-F3, according to the AO Spine Subaxial Cervical Spine Injury Classification System, with various associated neurologic injuries.

RESULTS

A total of 161 responses were received. Academic surgeons use the facet portion of the AO Spine classification system less frequently (61.6%) compared to hospital-employed and private practice surgeons (81.1% and 81.8%, respectively) (p = 0.029). The overall consensus was in favor of operative treatment for any facet fracture with radicular symptoms (N2) and for any fractures categorized as F2N2 and above. For F3N0 fractures, significantly less surgeons from Africa/Asia/Middle East (49%) and Europe (59.2%) chose operative treatment than from North/Latin/South America (74.1%) (p = 0.025). For F3N1 fractures, significantly less surgeons from Africa/Asia/Middle East (52%) and Europe (63.3%) recommended operative treatment than from North/Latin/South America (84.5%) (p = 0.001). More than 95% of surgeons included CT in their work-up of facet fractures, regardless of the type. No statistically significant differences were seen in the need for MRI to decide treatment.

CONCLUSION

Considerable agreement exists between surgeon preferences with regard to unilateral facet fracture management with few exceptions. F2N2 fracture subtypes and subtypes with radiculopathy (N2) appear to be the threshold for operative treatment.