Open posterior reduction and stabilization of a C1 burst fracture using mono-axial screws

Unstable jefferson burst fractures (JBF): Intraoperative stability testing after posterior atlas ring osteosynthesis (C1-RO) allows determination of surgical procedure extent

Introduction

Motion preserving atlas ring osteosynthesis (C1-RO) for unstable Jefferson burst fractures (JBF) with insufficiency of the transverse atlantal ligament (TAL) is under debate. There is controversy about when to apply C1-RO and when further stabilization is needed.

Research question

Is intraoperative stability testing after C1-RO with restoration of secondary stabilizers feasible, and what are mid-to long-term results of posterior C1-RO vs. C1-C2 ORIF in unstable Jefferson burst fractures with Dickman type I or II transverse atlantal ligament lesions based on intraoperative decision using this stability testing?

Material and methods

Five consecutive patients with unstable JBF were treated with posterior C1-RO or C1-C2 ORIF based on the findings after intraoperative reduction and posterior C1-RO and stability testing. This newly developed intraoperative stability test based on the findings of biomechanical studies is a fluoroscopically controlled manual C1-C2 test with a force of approximately 50 ​N posterior-anterior stress and a tilting maneuver after C1-RO with repositioning. Clinical and radiological results of the cases with C1-RO were analyzed 3.5-21 months postoperatively.

Results

Posterior C1-RO was performed in four patients. One case required C1-C2 fixation due to significant instability. In cases of C1-RO, stable bony fusions of the atlas ring were observed within a year. In flexion-extension views, the anterior atlanto-dental interval (AADI) did not increase until the latest follow-up. No complications were observed.

Discussion and conclusion

The described intraoperative stability test after posterior C1-RO in unstable JBF enables the determination if C1-RO is sufficient or C1-C2 ORIF is necessary for treatment.

Posterior Osteotomy and Osteosynthesis for Malunited Atlas Fracture: A Surgical Technique

Conservative treatment is commonly accepted and widely used for most atlas compression fractures. Malunion due to mismatching of the articular surfaces in C0-C1 and C1-C2 is therefore frequent even without associated instability. Such a result is considered acceptable in the elderly with low functional requests but should be avoided in young patients. Authors describe a new surgical technique to reduce and fix a nonunion and malunited fracture of the atlas through a posterior arch osteotomy followed by articular masses stabilization with polyaxial screws and precurved titanium rod. Rod prebending reduces lateral inclination of the screw heads during the reduction maneuver through compression applied between screw heads making it effective.

Posterior open reduction and internal fixation of C1 fractures: the C-clamp technique

BACKGROUND

The treatment of isolated atlas (C1) fractures is still controversial. The surgical management usually involves an arthrodesis of the atlanto-axial (C1-C2) joint with or without occipital fixation. We reviewed the senior author's series of posterior only open reduction and internal fixation (ORIF) of isolated C1 fractures.

METHODS

Retrospective analysis of consecutive patients with isolated C1 fractures, treated in one institution by posterior only ORIF between 2005 and 2017. All fractures of C1 with concomitant C2 or occipital condyle fractures were excluded. The C1 arch was reduced with C1 lateral mass screws, connected with a transverse rod in a C-clamp fashion. We analyzed neck pain on the visual analog scale (VAS) and imaging signs of instability on follow-up.

RESULTS

We identified eight patients, six males, and two females with a mean age of 37.9 years (range 20-71 years). All were neurologically intact before surgery, none had a documented transverse ligament disruption, and the mean gap between the fractured pieces was 5.3 mm. Five patients were treated < 72 h of injury, two patients had failed halo vest for 8-10 weeks, and one patient was operated after 6 months because of painful pseudarthrosis despite wearing a hard collar. One patient developed a transient neurological deficit due to vertebral artery dissection that had resolved completely at time of follow-up. The mean follow-up after surgery was 12.6 months (range 1-49 months) and mean preoperative neck pain (VAS 5.1) was significantly decreased (VAS 0.8; p < 0.001). On follow-up radiological evaluation, no instability was noted in any patient.

CONCLUSIONS

Posterior ORIF of C1 fractures may be an option for patients who fail or do not wish to pursue conservative management. The particular advantage of this technique over C1-C2 arthrodesis is the preserved range of rotational motion. Mono-axial screws seem to provide better reduction capacity.

Management of Isolated Atlas Fractures: A Retrospective Study of 65 Patients

BACKGROUND

Jefferson fractures, or burst fractures of the C1 vertebra, can be managed surgically or conservatively, depending on their stability.

METHODS

We identified all patients who were treated for a C1 fracture at our institution between 1999 and 2016 for retrospective analysis. Patients with any other concurrent cervical fractures or nontraumatic etiology of fracture were excluded. Stability was defined as either lateral mass displacement ≥7 mm on computed tomography or presence of transverse atlantal ligament disruption on magnetic resonance imaging. We collected data on patients' demographic, clinical, and radiographic presentation and identified variables independently associated with instability at presentation and failure to achieve fusion at follow-up.

RESULTS

We identified 65 patients. On multivariable regression, instability at presentation was independently associated with atlantodens interval (odds ratio [OR] 2.357, 95% confidence interval [CI] [0.0629-1.271], P = 0.099) and type 3 fracture (OR 6.081, 95% CI [1.068-34.612], P = 0.042). Failure to achieve fusion was independently associated with age (OR 1.226, 95% CI [1.007-1.495], P = 0.043), motor vehicle collision as mechanism of injury (OR 22834.3, 95% CI [3.135-1.66e8], P = 0.027), and type 2 fracture (OR 168.537, 95% CI [1.743-16292.92], P = 0.028). Type 3 fracture was positively associated with halo vest for management (OR 17.171, 95% CI [2.882-102.289], P = 0.002) and negatively associated with a rigid cervical collar for management (OR 0.0616, 95% CI [0.0104-0.3653], P = 0.002). All 4 patients who underwent surgery presented with unstable fracture (P = 0.0187).

CONCLUSIONS

Atlantodens interval, mechanism of injury, and fracture type affect Jefferson fracture management decisions and outcomes, including instability at presentation and fusion at follow-up. Most fractures were managed nonsurgically regardless of stability.

Unilateral lag-screw technique for an isolated anterior 1/4 atlas fracture

STUDY DESIGN

Fractures of the atlas are classified based on the fracture location and associated ligamentous injury. Among patients with atlas fractures treated using external immobilization, nonunion of the fracture could be seen.

OBJECTIVE

Ideally, treatment strategy for an unstable atlas fracture would involve limited fixation to maintain the fracture fragments in a reduced position without restricting the range of motion (ROM) of the atlantoaxial and atlantooccipital joints.

SUMMARY OF BACKGROUND DATA

Such a result can be established using either transoral limited internal fixation or limited posterior lateral mass fixation. However, due to high infection risk and technical difficulty, posterior approaches are preferred but none of these techniques can fully address anterior 1/4 atlas fractures such as in this case.

MATERIALS AND METHODS

A novel open and direct technique in which a unilateral lag screw was placed to reduce and stabilize a progressively widening isolated right-sided anterior 1/4 single fracture of C1 that was initially treated with a rigid cervical collar is described.

RESULTS

Radiological studies made after the surgery showed no implant failure, good cervical alignment, and good reduction with fusion of C1.

CONCLUSIONS

It is suggested that isolated C1 fractures can be surgically reduced and immobilized using a lateral compression screw to allow union and maintain both C1-0 and C1-2 motions, and in our knowledge this is the first description of the use of a lag screw to achieve reduction of distracted anterior 1/4 fracture fragments of the C1 from a posterior approach. This technique has the potential to become a valuable adjunct to the surgeon's armamentarium, in our opinion, only for fractures with distracted or comminuted fragments whose alignment would not be expected to significantly change with classical lateral mass screw reduction.

The effect of C1 bursting fracture on comparative anatomical relationship between the internal carotid artery and the atlas

PURPOSE

To describe the effect of the C1 bursting fracture on the location of the internal carotid artery (ICA) around the atlas.

METHODS

The authors analyzed the morphology of the atlas and the ICA in 15 patients with C1 bursting fracture and compared with control group (77 patients) without any pathology. All patients were evaluated with CT angiography for the anatomical assessment. The laterality of the ICA, the distances of the ICA from the midline, anterior tubercle, and ventral surface of the C1 lateral mass were compared between two groups. The distance between the lateral margin of the longus capitis muscle and the inner edge of the transverse foramen was also measured.

RESULTS

Medially located ICA was more common in the C1 bursting fracture group than control group (76.7 vs 42.8 %). There were no significant differences between 2 groups for the distance from the midline, anterior tubercle, and ventral surface of the C1 lateral mass, respectively. The distance of the longus capitis muscle to transverse foramen was 2.52 ± 2.09 and 4.15 ± 3.09 mm in each group, and there was statistically significant difference (p < 0.01).

CONCLUSIONS

Lateral displacement of the bony structure of C1 bursting fracture changes the relative location of the ICA medially, which increase the injury risk during the bicortical C1 screw insertion. These data suggest that CT angiography or enhanced CT scans can give critical information to choose the ideal fixation technique and the proper trajectory of the screws for C1 bursting fracture.

Unstable Jefferson fractures: Results of transoral osteosynthesis

BACKGROUND

Majority of C1 fractures can be effectively treated conservatively by immobilization or traction unless there is an injury to the transverse ligament. Conservative treatment usually involves a long period of immobilization in a halo-vest. Surgical intervention generally involves fusion, eliminating the motion of the upper cervical spine. We describe the treatment of unstable Jefferson fractures designed to avoid these problems of both conservative and invasive methods.

MATERIALS AND METHODS

A retrospective review of 12 patients with unstable Jefferson fractures treated with transoral osteosynthesis of C1 between July 2008 and December 2011 was performed. A steel plate and C1 lateral mass screw fixation were used to repair the unstable Jefferson fractures. Our study group included eight males and four females with an average age of 33 years (range 23-62 years).

RESULTS

Patients were followed up for an average of 16 months after surgery. Range of motion of the cervical spine was by and large physiologic: Average flexion 35° (range 28-40°), average extension 42° (range 30-48°). Lateral bending to the right and left averaged 30° and 28° respectively (range 12-36° and 14-32° respectively). The average postoperative rotation of the atlantoaxial joint, evaluated by functional computed tomography scan was 60° (range 35-72°). Total average lateral displacement of the lateral masses was 7.0 mm before surgery (range 5-12 mm), which improved to 3.5 mm after surgery (range 1-6.5 mm). The total average difference of the atlanto-dens interval in flexion and extension after surgery was 1.0 mm (range 1-3 mm).

CONCLUSIONS

Transoral osteosynthesis of the anterior ring using C1 lateral mass screws is a viable option for treating unstable Jefferson fractures, which allows maintenance of rotation at the C1-C2 joint and restoration of congruency of the atlanto-occipital and atlantoaxial joints.