Predisposing Factors of Fracture Nonunion After Posterior C1 Lateral Mass Screws Combined with C2 Pedicle/Laminar Screw Fixation for Type II Odontoid Fracture

Combined Anterior Odontoid Screw Fixation and C1-C2 Jefferson Fracture Anterior Fixation: A Step-by-Step Technical Note

BACKGROUND

Combined triple atlas (C1)-axis (C2) fixation has been described in previous literature as a safe, effective, and minimally invasive procedure for complex atlas and odontoid fractures that allows for a greater range of motion compared with posterior approaches and atlanto-occipital fusion. However, it is rarely performed due to the occipital-cervical diastasis resulting from often-fractured C1 joint masses. No evidence-based consensus has been reached regarding the treatment of complex atlantoaxial fractures, and the choice of surgical strategy is based only on clinical experience.

METHODS

We report the combined triple C1-C2 fixation technique with manual reduction of the joint masses during patient positioning on the operating table, which allowed for effective stabilization during a single surgical session. We describe our experience in the management of a 75-year-old patient presenting with an acute complex type II fracture of C1, which also involved 1 lateral mass, combined with a type II odontoid fracture and occipital-cervical diastasis.

RESULTS

We provide a step-by-step guide for combined triple C1-C2 anterior fixation with manual fracture reduction and describe the clinical case of an acute complex type II fracture of C1, which also involved 1 lateral mass, combined with a type II odontoid fracture and occipital-cervical diastasis.

CONCLUSIONS

Combined triple C1-C2 fixation represents a safe and efficient minimally invasive anterior approach for complex type II fractures of C1 with type II odontoid fractures. Manual reduction of the joint masses during patient positioning allows for effective stabilization in a single surgical session.

A Predictive Model to Identify Treatment-related Risk Factors for Odontoid Fracture Nonunion Using Machine Learning

STUDY DESIGN

Multicenter retrospective analysis of routinely collected data.

OBJECTIVE

The underlying aim of this study was to identify potential treatment-related risk factors for odontoid fracture nonunion while accounting for known patient- and injury-related risk factors.

SUMMARY OF BACKGROUND DATA

Type II and III odontoid fractures represent the most common cervical spine fracture in elderly patients and are associated with a relatively high nonunion rate. The management of odontoid fractures is controversial and treatment strategies range from conservative treatment to extensive surgical stabilization and fusion.

METHODS

A total of 415 individuals who sustained odontoid fracture and were treated in either of four tertiary referral centers in Austria and Germany were included in the study. We included the following potential contributing factors for fracture nonunion in cross-validated extreme gradient boosted (XGBoost) and binary logistic regression models: age, gender, fracture displacement, mechanism of injury (high vs. low energy), fracture classification (Anderson II vs. III), presence of comorbidities (Charlson comorbidity index), and treatment (conservative, anterior screw fixation with one or two screws, posterior C1/C2 spondylodesis, cervico-occipital C0-C4 fusion).

RESULTS

In our cohort, 187 (45%) had radiologically confirmed odontoid nonunion six months postinjury. The odds for nonunion increase significantly with age, and are lower in type III compared to type II fractures. Also, odds for nonunion are significantly lower in posterior C1/C2 spondylodesis, and C0-C4 fusion compared to conservative treatment. Importantly, odds are not statistically significantly lower in the group treated with anterior screw fixation compared to conservative treatment. The factors gender, fracture displacement, mechanism of injury, and the presence of comorbidities did not produce significant odds.

CONCLUSION

Higher age, type II fractures, and conservative treatment are the main risk factors for odontoid nonunion. Anterior screw fixation did not differ significantly from conservative treatment in terms of fracture union.

LEVEL OF EVIDENCE

3.

C1-ring osteosynthesis versus C1-2 fixation fusion in the treatment of unstable atlas fractures: a multicenter, prospective, randomized controlled study with 5-year follow-up

OBJECTIVE

The aim of the present study was to compare the long-term effects of posterior C1-ring osteosynthesis and C1-2 fixation fusion in the treatment of unstable atlas fractures.

METHODS

A multicenter, prospective, randomized controlled trial was conducted to analyze 73 patients with atlas fractures who underwent posterior fixation. The intervention group was treated with C1-ring osteosynthesis, and the control group was treated with C1-2 fixation fusion. The patients were followed up for 6 months, 1 year, 2 years, and 5 years after the operation.

RESULTS

Fifty-two patients had complete data at the last follow-up. The visual analog scale (VAS) score for neck pain in the intervention group was lower than that in the control group (p < 0.001). The operation time, intraoperative blood loss, radiation dose, bedridden period, hospital stay, and cost in the intervention group were significantly lower than those in the control group (p < 0.001). At the last follow-up, the Neck Disability Index in the intervention group was higher than that of the control group, and the angle of flexion-extension and axial rotation in the intervention group were greater than those in the control group (p < 0.001).

CONCLUSIONS

In this study, the authors found that posterior C1-ring osteosynthesis is superior to C1-2 fixation fusion in terms of long-term relief of neck pain and preservation of the physiological function of the cervical vertebrae. This technique is a reliable choice for the treatment of unstable C1 fractures.

Healing process of Type II odontoid fractures after C1-C2 posterior screw fixation: Predictive factors for pseudoarthrosis

Background:

The healing process after C1-C2 posterior screw fixation (C1-C2 PSF) for odontoid fractures is not well understood. Here, we evaluated such processes and identified factors potentially contributing to pseudoarthroses following fusions for Type II odontoid fractures.

Methods:

Pre- and post-operative cervical radiographs and computed tomography (CT) images from 15 patients with preoperative Type II odontoid fractures who underwent C1-C2 PSF were retrospectively reviewed.

Results:

CT images identified three areas of bone fusion: The primary fracture site in the dens (9/15 patients, 60%), the atlanto-dental interspace (ADI) (10/15, 67%), and C1-C2 interlaminar space after onlay bone grafting (4/15, 27%). All patients showed bone fusion in at least one of three areas, while only one patient (6.7%) achieved bone fusion in all three areas. With these overall criteria, nine of 15 patients (60%) were considered fused, while six patients (40%) were determined to exhibit pseudoarthroses. Univariate analyzes showed that the preoperative C2-C7 SVA for the nonunion group was significantly larger versus the union group, and bone fusion at the level of the ADI was significantly more common in the nonunion versus the union group.

Conclusion:

CT studies identified three anatomical areas where bone fusion likely occurs after C1-C2 PSF. Increased sagittal balance in the cervical spine may negatively impact the fusion of odontoid fractures. Further, bone fusion occurring at other sites, not the primary fracture location, through stress shielding may contribute to delayed or failed fusions.

Upper Cervical Spine Trauma: WFNS Spine Committee Recommendations

Craniovertebral junction (CVJ) trauma is a challenging clinical condition. Being a highly mobile functional unit at the junction of the skull and the vertebral column, traumatic events in this area may produce devastating neurological complications and death. Additionally, many of the CVJ traumatic injuries can be left undiagnosed or even raise difficult treatment dilemmas. We present a literature review in the format of recommendations on the diagnosis and management of different scenarios for upper cervical trauma and produce recommendations, which can be applicable to various areas of the globe.

Comparison of clinical and radiological outcomes between modified Gallie graft fusion-wiring technique and posterior cervical screw constructs for Type II odontoid fractures

The aim of this study was to compare clinical and radiological outcomes between modified Gallie graft fusion-wiring technique and posterior cervical screw constructs for Type II odontoid fractures, and hope to provide references in decision making and surgical planning for both spinal surgeons and surgically treated patients.This is a retrospective study. By retrieving the medical records from January 2005 to July 2015 in our hospital, 53 Type II odontoid fracture patients were reviewed. According to the instrumentation type, patients were divided into 2 groups: Wiring group and Screw group. Three categorized factors were analyzed statistically: patient characteristics: age, body mass index, preoperative neurological status, duration, complicated injuries; surgical variables: surgery time, blood loss, vertebral artery injury, spinal cord or nerve root injury, major systemic complications, wound infection, pain at the bone donor area, instrumentation failure, revision rate; and radiographic parameters: preoperative and final follow-up data of C0-2 curvature, C2-7 curvature, C2-C7 sagittal vertical axis, C7 slope, fracture classification, separation, and displacement of odontoid fracture, fusion rate. An additional comparison of surgical outcomes was done, including patient satisfaction, visual analog scale score for neck pain, neck stiffness, medical expense.There was no statistically significant difference between the 2 groups in patient characteristics of age, sex, body mass index, preoperative neurological status, duration, and complicated injuries. No statistically significant difference was noted in surgical variables of blood loss, vertebral artery injury, spinal cord or nerve root injury, major systemic complications, wound infection, bone harvested zone pain, instrumentation failure, revision rate. The surgery time was shorter in Wiring group than that in Screw group, with a statistically significant difference. We noted no significant difference between the 2 groups when comparing radiographic parameters of preoperative and final follow-up data of C0-2 curvature, C2-C7 sagittal vertical axis, fracture classification, the separation and displacement of odontoid fracture, and fusion rate. Although we noted no significant difference in preoperative C2-7 curvature and C7 slope, the final follow-up data showed that C2-7 curvature and C7 slope were smaller in Wiring group than that in Screw group. We noted no significant difference in visual analog scale score, neck stiffness, and neurological status at final follow-up. The medical expense was less in Wiring group; the patient satisfaction was lower in the Wiring group than that in the Screw group.The modified Gallie graft fusion-wiring technique provided solid fusion and stabilization for patients with Type II odontoid fractures, Gallie graft fusion-wiring resulted in less surgery time, less medical expense, but lower patient satisfaction when compared with the posterior cervical screw constructs.

The comparison of clinical outcome of fresh type II odontoid fracture treatment between anterior cannulated screws fixation and posterior instrumentation of C1-2 without fusion: a retrospective cohort study

Background

Recently, the excellent outcomes of temporary fixation of C1-2 without fusion in the treatment of odontoid fracture had been reported. It is still unclear if this technique could achieve the equivalent outcomes as the golden standard technique of anterior screw fixation. The objective of this study is to compare the clinical outcome of two treatments of fresh type II odontoid fracture: anterior cannulated screws fixation (ACSF) versus posterior instrumentation of C1-2 without fusion (PIWF).

Methods

This is a retrospective study. This series included 28 males and 8 females, and the mean age was 41.5 years (range, 22 to 70 years). Eleven patients were treated with ACSF, and 25 patients with PIWF. For PIWF, the implants were removed after fracture union was confirmed at 0.75~1.5 years later. All patients underwent preoperative and serial postoperative clinical examinations at approximately 3 months, 6 months, and annually thereafter. The neck disability index (NDI) was used to assess the neck discomfort caused by the operation. The range of rotary motion was evaluated at each visit. All fractures were reassessed postoperatively with serial X-films and CT scans of the cervical spine at each follow-up visit, to evaluate screw position, fracture alignment, and fusion status.

Results

All patients achieved immediate spinal stabilization after surgery, and none experienced neurologic deterioration. The follow-up periods ranged from 24 to 60 months. The average range of neck rotation was dramatically lost in PIWF after fixation (46° and 89° respectively in ACSF and PIWF), and recovered to 83° after the implant was removed. The NDI in PIWF was statistically higher than that in ACSF (5 and 13% respectively in ACSF and PIWF) after the first operation and decreased to 8% 1 year after the secondary operation. The fusion rates were 90.9 and 96% respectively in ACSF and PIWF. Both groups had a case of fracture non-union.

Conclusions

For fresh type II odontoid fractures, high rate of fracture union can be achieved by both ACSF and PIWF. For most fresh type II odontoid fractures, anterior screw fixation was the best option for its simplicity and preservation of normal atlanto-axial rotary function. Posterior instrumentation without fusion could preserve most of the atlanto-axial rotary function and lead to moderate neck discomfort and is also a good alternative if anterior screw fixation is contraindicated.