Unstable atlas fracture treatment by anterior plate C1-ring osteosynthesis using a transoral approach

Isolated C1 arch fractures: C1-2 fusion vs. C1 osteosynthesis - surgical strategies for potentially unstable injuries

STUDY DESIGN

Narrative Review.

OBJECTIVES

The premise of this review is to provide a review of the literature pertaining to studies describing outcomes of surgical cohorts when implementing C1 osteosynthesis for arch fractures with or without transverse atlantal ligamentous (TAL) injury.

METHODS

A comprehensive search strategy was implemented across several search engines to identify studies which evaluate the outcomes of C1 osteosynthesis for patients with C1 arch fractures with and without TAL injury.

RESULTS

Ten studies were identified. Parameters reported included osteosynthesis fusion rates, deformity correction, preservation of motion segments, patient reported outcome measures and overall complications. Overall, C1 osteosynthesis showed excellent fusion rates with complications comparable to traditional techniques denoted in literature. Furthermore, the osteosynthesis technique depicted good overall deformity correction and preservation of motion segments, in addition to good patient reported outcomes.

CONCLUSION

It appears C1 osteosynthesis offers a safe and efficacious alternative option for the surgical treatment of C1 fractures with TAL rupture. It has the potential to reduce deformity, increase ROM, improve PROMs and has complication rates comparable with those of fusion techniques. However more robust prospective evidence is required.

Comparison of Transoral Anterior Jefferson-Fracture Reduction Plate and Posterior Screw-Rod Fixation in C1-Ring Osteosynthesis for Unstable Atlas Fractures

OBJECTIVE

To compare the clinical outcomes of transoral anterior Jefferson-fracture reduction plate (JeRP) and posterior screw rod (PSR) surgery for unstable atlas fractures via C1-ring osteosynthesis.

METHODS

From June 2009 to June 2022, 49 consecutive patients with unstable atlas fractures were treated by transoral anterior JeRP fixation (JeRP group) or PSR fixation (PSR group) and followed up at General Hospital of Southern Theatre Command of PLA; 30 males and 19 females were included. The visual analogue scale (VAS) score, Neck Disability Index (NDI), distance to anterior arch fracture (DAAF), distance to posterior arch fracture (DPAF), lateral mass displacement (LMD), Redlund-Johnell value, postoperative complications, and fracture healing rate were retrospectively collected and statistically analyzed.

RESULTS

Compared with that in the PSR group, the bleeding volume in the JeRP group was lower, and the length of hospital stay was longer. The VAS scores and NDIs of both groups were significantly improved after surgery. The postoperative DAAF and DPAF were significantly smaller after surgery in both groups. Compared with the significantly shorter DPAF in the PSR group, the JeRP group had a smaller DAAF, shorter LMDs and larger Redlund-Johnell value postoperatively and at the final follow-up. The fracture healing rate at 3 months after surgery was significantly greater in the JeRP group (p < 0.05).

CONCLUSION

Both C1-ring osteosynthesis procedures for treating unstable atlas fractures yield satisfactory clinical outcomes. Transoral anterior JeRP fixation is more effective than PSR fixation for holistic fracture reduction and short-term fracture healing, but the hospital stay is longer.

Monoaxial Screws Versus Polyaxial Screws Osteosynthesis for Unstable Atlas Fractures: A Retrospective, Comparative Study With a Minimum Follow-Up of 3 years

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The study aimed to compare the radiological parameters, clinical outcomes, and long-term effects of the posterior osteosynthesis with polyaxial screw-rod system and the monoaxial screw-rod system in the treatment of unstable atlas fractures.

METHODS

We retrospectively analyzed the clinical data of 33 patients with posterior ORIF for unstable atlas fractures in our hospital from August 2013 to June 2020, with a minimum of 3 years of follow-up. Polyaxial screws (group A) were used in 12 patients and monoaxial screws (group B) in 21 patients. Perioperative data, radiological parameters, and clinical outcomes were collected and compared between the 2 surgical approaches.

RESULTS

The operative time, blood loss, time of screw-rod system placement, and hospital stay were significantly lower in group A than in group B. At the last follow-up, the visual analog scale (VAS) score and anterior arch reduction rate of the atlas in group A were lower than those in group B, while the lateral mass displacement (LMD) in group A was higher than that in group B. There was no significant difference between Group A and Group B in terms of the anterior atlantodental interval (AADI), posterior arch reduction rate of the atlas, range of motion (ROM), and neck disability index (NDI).

CONCLUSIONS

Monoaxial screws can achieve better reduction results for unstable atlas fractures, especially for the anterior arch of atlas. However, the surgical operation of monoaxial screws is more complicated than that of polyaxial screws and has more complications. Appropriate implants should be selected for the treatment of unstable atlas fractures based on the type of atlas fracture, the experience of surgeons, and the demands of patients.

Direct osteosynthesis in the treatment of atlas burst fractures: a systematic review

PURPOSE

The treatment of unstable atlas fractures remains a controversial topic. The study aims at assessing the prognosis and efficacy of osteosynthesis for unstable atlas fractures through a review of the current literature and additionally aims to compare outcomes between the transoral and posterior approaches.

METHODS

A systematic review of databases including PubMed, EMBASE, Cochrane, Web of Science, CNKI, and Wanfang was conducted. Titles and abstracts were screened by two reviewers to identify studies meeting pre-defined inclusion criteria for comprehensive analysis.

RESULTS

The systematic review included 28 articles, 19 employing the posterior approach and 9 utilizing the transoral approach. It covered osteosynthesis in 297 patients with unstable atlas fractures, comprising 169 treated via the posterior approach and 128 via the transoral approach. Analysis revealed high healing rates and clinical improvement in both approaches, evidenced by improvements in the visual analog scale, range of motion, atlantodens interval, and lateral displacement distance post-surgery.

CONCLUSION

Osteosynthesis offers effective treatment for unstable atlas fractures. Both transoral and posterior approaches can achieve good clinical outcomes for fracture, and biomechanical studies have confirmed that osteosynthesis can maintain the stability of the occipitocervical region, preserve the motor function of the atlantoaxial and occipito-atlantoaxial joints, and greatly improve the quality of life of patients. However, variations exist in the indications and surgical risks associated with each method, necessitating their selection based on a thorough clinical evaluation of the patient's condition.

Design of a novel lateral mass screw-plate system for the treatment of unstable atlas fractures: a finite element analysis

BACKGROUND

Osteosynthesis of unstable atlas fractures preserves joint motion and therefore has a distinct advantage over a range of treatment procedures. To prevent the potential disadvantages associated with osteosynthesis, a new atlas lateral mass screw-plate (LMSP) system has been designed. However, the biomechanical role of using the LMSP system in atlas internal fixation is not known. The aim of this study was to compare the biomechanical stability of a new LMSP with traditional posterior screw and rod (PSR) fixation techniques on the occipitocervical junction (C0-C2) through finite element analysis.

METHODS

A nonlinear C0-C2 finite element model of the intact upper cervical spine was developed and validated. The unstable model using the PSR system was then compared with the model using the LMSP system for fixation. A vertical load of 40 N was applied to the C0 to simulate head weight, while a torque of 1.5 Nm was applied to the C0 to simulate flexion, extension, lateral bending, and axial rotation.

RESULTS

The range of motion of both systems was close to the intact model. Compared with the LMSP system model, the PSR system model increased flexion, extension, lateral bending, and axial rotation by 4.9%, 3.0%, 5.0%, and 29.5% in the C0-C1 segments, and 4.9%, 2.7%, 2.4%, and 22.6% in the C1-C2, respectively. In flexion, extension, and lateral bending motion, the LMSP system model exhibited similar stress to the PSR system model, while in axial rotation, the PSR system model exhibited higher stress.

CONCLUSIONS

The findings of our study indicate that the two tested system models provide comparable stability. However, better stability was achieved during axial rotation with the LMSP system, and in this system, the maximum von Mises stress was less than that of the PSR one. As the atlantoaxial joint functions primarily as a rotational joint, the use of the LMSP system may provide a more stable environment for the joint that has become unstable due to fracture.

Direct C1 posterior arch screws for reduction and osteosynthesis in the treatment of Jefferson fracture

The surgical treatment of Jefferson fractures generally involves solid fusion, which limits the range of motion of the upper cervical spine. Herein, we present a case of a Jefferson fracture that was surgically treated using direct C1 posterior arch screw reduction and osteosynthesis instead of fusion surgery. Postoperative computed tomography (CT) and plain radiography revealed that both C1 posterior arch screws were well positioned, and placing lag screws at the C1 level played a key role in fracture reduction. The present case highlights a surgical technique, which can preserve neck motion by using lag screws for reduction and osteosynthesis.

Transoral unilateral lag screw osteosynthesis for coronal split fracture of the lateral mass of the atlas - case report, operative technique and review of the literature

Introduction

Atlas ring fractures, which account for 1.3% of all spinal fractures, are predominantly managed conservatively. However, in certain cases, surgical treatment may be necessary depending on the type of fracture, degree of comminution, fracture location, and associated ligamentous injuries. Surgical stabilization frequently results in a posterior C1-2 or C0-2 fusion, which restricts movement, particularly craniocervical rotation. Coronal split fractures of the lateral mass need to be reduced and fixed due to dislocation, instability and secondary osteoarthritis. The preferred treatment approach involves internal fixation of the reduced fracture fragments, while avoiding restriction of the upper cervical spine's range of motion (ROM).

Research question

Is unilateral anterior transoral lag screw for treatment of unstable coronal split fracture of lateral mass of the atlas feasible and a safe treatment option?

Case Report Material and Methods

We report on a 55-year-old female suffering from polytrauma with multiple spinal and extremity injuries.

Results

A coronal split fracture of the lateral mass of the atlas was treated minimally invasive with a transoral lag screw technique to reduce and fix the fracture that has a tendency for fracture gap widening. Stable fixation and fracture union and thus restoration of function was achieved.

Discussion and conclusion

Transoral lag screw osteosynthesis for coronal split fracture of the lateral mass of the atlas is a potential treatment option in selected cases to preserve mobility in the upper cervical spine after spinal trauma.

The use of a novel reduction plate in transoral anterior C1-ring osteosynthesis for unstable atlas fractures

Background

Transoral anterior C1-ring osteosynthesis has been reported as an effective treatment for unstable atlas fracture, which aims to preserve important C1-C2 motion. However, previous studies have shown that the anterior fixation plates used in this technique were not suitable for the anterior anatomy of the atlas and lacked an intraoperative reduction mechanism.

Objective

This study aims to evaluate the clinical effects of a novel reduction plate used in transoral anterior C1-ring osteosynthesis for unstable atlas fractures.

Methods

30 patients with unstable atlas fractures treated by this technique from June 2011 to June 2016 were included in this study. The patients' clinical data and radiographs were reviewed, and the reduction of the fracture, internal fixation placement, and bone fusion were assessed using pre- and postoperative images. The patients' neurological function, rotatory range of motion, and pain levels were evaluated clinically during follow-up.

Results

All 30 surgeries were successfully performed, and the average follow-up duration was 23.5 ± 9.5 months (range 9-48 months). One patient suffered atlantoaxial instability during the follow-up and was treated with posterior atlantoaxial fusion. The remaining 29 patients had satisfactory clinical outcomes, with ideal fracture reduction, good screw and plate placement, well-preserved range of motion, neck pain alleviation and solid bone fusion. There were no vascular or neurological complications during the operation or follow-up.

Conclusions

The use of this novel reduction plate in transoral anterior C1-ring osteosynthesis is a safe and effective surgical option in the treatment of unstable atlas fractures. This technique offers an immediate intraoperative reduction mechanism, which provides satisfactory fracture reduction, bone fusion, and preservation of C1-C2 motion.

Posterior temporary fixation of C1-C2 screw-rod system for unstable C1 burst fracture

Whether an unstable C1 burst fracture should be treated surgically or conservatively is controversial. The purpose of this study is to evaluate the effectiveness and motion-preserving function of temporary fixation of C1-C2 screw-rod system for the reduction and fixation of unstable C1 burst fracture. We retrospectively reviewed 10 patients who were treated with posterior C1-C2 temporary fixation without fusion. We assessed age at surgery, gender, pre- and postoperative visual analog scale (VAS), Neck Disability Index (NDI), atlanto-dens interval (ADI), lateral mass distance (LMD), and rotation function of C1-C2 complex. Six males and 4 females were included in our study. The average follow-up duration was 14.1 ± 1.37 months. The left-to-right ROMs of C1-C2 rotation was 9.6° ± 1.42°. The preoperative cervical VAS was 8.30 ± 0.48; the postoperative cervical VAS of C1-C2 fusion was 2.90 ± 0.57. The preoperative VAS for removal was 2.0 ± 0.00, and the postoperative VAS for removal was 2.3 ± 0.48. The preoperative cervical NDI was 81.40% ± 2.07%, the postoperative cervical NDI of C1-C2 fusion was 18.10% ± 1.52%. The preoperative NDI for removal was 15.9% ± 1.20%. The postoperative NDI for removal was 14.5% ± 1.08%. The preoperative ADI was 4.43 ± 0.34 mm, and postoperative ADI was 1.94 ± 0.72 mm. The preoperative LMD was 6.36 ± 0.58 mm, and postoperative LMD was 1.64 ± 0.31 mm. Posterior temporary C1-C2 fixation can achieve a good fusion and satisfied reduction of C1 fracture, relieve the pain, improve the cervical function outcome, but may reduce the rotational range of motion of C1-C2. Posterior C1-C2 temporary fixation without fusion was not suitable for C1 burst fracture. We recommend permanent C1-C2 fixation and fusion for C1 burst fracture if surgery is necessary.

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.

Direct Internal Fixation for Unstable Atlas Fractures

PURPOSE

To investigate the radiologic and clinical outcomes of direct internal fixation for unstable atlas fractures.

MATERIALS AND METHODS

This retrospective study included 12 patients with unstable atlas fractures surgically treated using C1 lateral mass screws, rods, and transverse connector constructs. Nine lateral mass fractures with transverse atlantal ligament (TAL) avulsion injury and three 4-part fractures with TAL injury (two avulsion injuries, one TAL substance tear) were treated. Radiologic outcomes included the anterior atlantodental interval (AADI) in flexion and extension cervical spine lateral radiographs at 6 months and 1 year after treatment. CT was also performed to visualize bony healing of the atlas at 6 months and 1 year. Visual Analog Scale (VAS) scores for neck pain, Neck Disability Index (NDI) values, and cervical range of motion (flexion, extension, and rotation) were recorded at 6 months after surgery.

RESULTS

The mean postoperative extension and flexion AADIs were 3.79±1.56 (mean±SD) and 3.13±1.01 mm, respectively. Then mean AADI was 3.42±1.34 and 3.33±1.24 mm at 6 months and 1 year after surgery, respectively. At 1 year after surgery, 11 patients showed bony healing of the atlas on CT images. Only one patient underwent revision surgery 8 months after primary surgery due to nonunion and instability findings. The mean VAS score for neck pain was 0.92±0.99, and the mean NDI value was 8.08±5.70.

CONCLUSION

C1 motion-preserving direct internal fixation technique results in good reduction and stabilization of unstable atlas fractures. This technique allows for the preservation of craniocervical and atlantoaxial motion.

Diagnosis and management of isolated C1 fractures: A systematic review

Objective

Atlas fractures are a common craniocervical injury, often resulting from trauma. However, diagnosis and management of atlas fractures continues to be the subject of controversy. We aimed to characterize the factors related to diagnosis of atlas fractures, delineate important considerations in selecting the optimal management for a patient with an atlas fracture, and compare outcomes of surgical and conservative management.

Methods:

We performed a systematic review using PubMed, Embase, and Scopus to identify articles that analyzed diagnosis and management of isolated atlas fractures published between 2013 and 2020. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full.

Results:

Of 305 resultant articles, 13 were included. C1:C2 ratio and lateral mass displacement (LMD) were used to predict transverse atlantal ligament (TAL) injury. Surgery promoted high fusion rates overall. Stable atlas fractures achieved high fusion rates with conservative management, while spinal fusion promoted greater fusion rates than halo vest immobilization management for unstable fractures. Visual Analog Scale scores, range of motion, and/or LMD improved after surgery. LMD increased for unilateral sagittal split fractures with TAL injury after conservative treatment.

Conclusion:

Stable atlas fractures can be sufficiently treated conservatively. Unstable atlas fractures can be managed both conservatively and surgically, while surgery is associated with favorable outcomes for unstable isolated atlas fractures. Future studies are necessary to further guide risk stratification and treatment approaches in management of the patients with isolated atlas fractures.

Anterior reduction and C1-ring osteosynthesis with Jefferson-fracture reduction plate (JeRP) via transoral approach for unstable atlas fractures

Background

To introduce a novel transoral instrumentation in the treatment of unstable fractures of the atlas.

Methods

From January 2008 to May 2018, 22 patients with unstable C1 fractures who received Jefferson-fracture reduction plate (JeRP) via transoral approach were retrospectively analyzed. The case history and the radiographs before and after surgery were noted. The type of fracture, the reduction of the fracture, and position of the internal fixation were assessed through preoperative and postoperative CT scans.

Results

All 22 patients successfully underwent anterior C1-ring osteosynthesis using the JeRP system, with a follow-up of 26.84 ± 9.23 months. Among them, 9 patients had transverse atlantal ligament (TAL) injury, including 3 in Dickman type I and 6 in type II. The preoperative lateral mass displacement (LMD) decreased from 7.13 ± 1.46 mm to 1.02 ± 0.65 mm after the operation. Bone union was achieved in all patients without implant failure or loss of reduction. There were no surgery-related complications, such as wound infection, neurological deficit, or vertebral artery injury. However, atlantoaxial dislocation occurred in 3 patients with Dickman type I TAL injury 3 months postoperatively without any neurological symptoms or neck pain.

Conclusions

Transoral C1-ring osteosynthesis with JeRP is an effective surgical strategy to treat unstable atlas fractures with a safe, direct, and satisfactory reduction. The primary indication for the JeRP system is an unstable fracture (Gehweiler type I/III) or/ and TAL injury (Dickman type II).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04628-4.

Motion-preserving treatment of unstable atlas fracture: transoral anterior C1-ring osteosynthesis using a laminoplasty plate

Background

C1-ring osteosynthesis is a valid alternative to posterior C1–C2 or C0–C2 fusion to preserve important C1–C2 motion in the treatment of unstable atlas fractures. Nevertheless, the fixation instruments used in current studies for transoral anterior C1-ring osteosynthesis were not suitable for anterior anatomy of the atlas or did not have reduction mechanism. We therefore present this report to investigate preliminary clinical effects of transoral anterior C1-ring osteosynthesis using a laminoplasty plate in unstable atlas fractures.

Methods

From January 2014 to December 2017, 13 patients with unstable atlas fractures were retrospectively reviewed. All patients were treated with transoral anterior C1-ring osteosynthesis using a laminoplasty plate. Pre- and postoperative images were obtained to assess reduction of the fracture, internal fixation placement, and bone union. Neurological function, range of motion, and pain levels were evaluated clinically on follow-up.

Results

The surgeries were successfully performed in all cases. The average follow-up duration was 16.6 ± 4.4 months (range 12–24 months). One patient suffered screw loosening after operation and underwent replacement operation subsequently. Satisfactory clinical outcomes were achieved in all patients with ideal fracture reduction, reliable plate placement, well-preserved range of motion, and neck pain alleviation. All patients achieved bone union of fractures without loss of reduction or implant failure or C1–C2 instability during the follow-up. No vascular or neurological complication was noted during the operation and follow-up.

Conclusions

Transoral anterior C1-ring osteosynthesis using a laminoplasty plate is a effective surgical treatment for unstable atlas fractures. This technique has a ingenious reduction mechanism, and can provide satisfactory bone union and preservation of C1–C2 motion.

[Progress in treatment of unstable atlas fracture]

OBJECTIVE

To summarize the progress in treatment of unstable atlas fracture, the existing problems, and the research direction.

METHODS

Related literature at home and abroad was reviewed. The stability evaluation of atlas fracture and treatment methods were introduced, and the selection of surgical approach and fixation instruments in treatment of unstable atlas fracture were summarized and analyzed.

RESULTS

At present, atlas fractures are considered as unstable fractures except single anterior arch fractures with complete transverse ligament or simple posterior arch fractures. The treatment of unstable atlas fracture has been developed from nonsurgical treatment and traditional fusion surgery to single-segment fixation. Nonsurgical treatment is less effective, while traditional fusion surgery has a disadvantage of limited the motion of the upper cervical spine. Single-segment fixation can not only restore and fix the fracture, but also preserve the upper cervical motion function. Single-segment fixation approaches include posterior and transoral approaches, and the fixation instruments are being constantly improved, mainly including screw-rod system, screw-plate system, and plate system.

CONCLUSION

For unstable atlas fracture, single-segment fixation is an ideal surgical method, and has more advantages when compared with nonsurgical treatment and traditional fusion surgery. Single-segment fixation via transoral approach is more direct for atlas anterior arch fracture reduction, but there is a high risk of infection; and single-segment fixation via posterior approach is less effective for the reduction of atlas anterior arch fracture. Therefore, a better reduction method should be explored.

Treatment strategy of unstable atlas fracture: A retrospective study of 21 patients

At present, the posterior cervical approach with open reduction and internal fixation (ORIF) remains a commonly effective treatment for unstable Atlas fracture. However, the inserted screws into the C1 lateral mass of some unstable atlas fracture are very difficult, so that the operation is forced to change into C0 to C2 fusion. In order to improve the successful rate of lateral mass screw placement, we introduced a method of fixing lateral mass with a towel clamp in posterior transpedicular fixation, and explore the efficacy and feasibility.Twenty-one consecutive patients with unstable atlas fracture were treated via this method from October 2012 to July 2017. All cases had neck pain and restricted motion of neck movement on admission. Electronic medical records and pre- and postoperative radiographs were reviewed. Screw and rod placement, bone fusion, and spinal cord integrity were assessed via long-term follow-up with anteroposterior and lateral radiographs and computed tomography. Follow-up included clinical assessment of neurological function, assessment of pain using the visual analog scale (VAS), and assessment of the activities of daily living using the neck disability index (NDI).The mean follow-up duration was 22.1 months (range: 12-54 months). No screw loosening or breakage, plate displacement, neurovascular injury, and severe complications occurred during follow-up. The mean operative time was 112.4 ± 14.9 min (range: 82-135 min), and mean blood loss was 386.2 ± 147.9 mL (range: 210-850 mL). One patient experienced continuous neck pain postoperatively, but this gradually disappeared with analgesic administration. At final follow-up, all patients had bone fusion, the VAS scores and NDI were significantly improved compared with preoperatively.Fixing the C1 lateral mass with a towel clamp during posterior transpedicular fixation for unstable atlas fracture appears to be a safe and reliable method, with the advantages of being a simple technique with few complications.

Why you should wear your seatbelt on an airplane: Burst fracture of the atlas (jefferson fracture) due to in-flight turbulence

The Jefferson fracture is a burst-type fracture to the atlas first described in 1919, characterized by anterior and posterior fractures of the weak C1 ring caused by a sudden axial load to the vertex of the skull. Here we report a Jefferson fracture caused by head trauma due to mid-flight turbulence in an unrestrained 56-year-old male airline passenger. Imaging revealed a comminuted burst fracture of the atlas with an avulsion fracture of the transverse atlantal ligament. The patient was treated conservatively in a Miami-J collar with close clinical and radiographic follow-up. Lateral flexion-extension radiographs demonstrated fracture stability, and clinically the patient lacked pain or neurologic symptoms at 12 weeks from injury. To our knowledge this is the first report of a Jefferson fracture caused by axial compression attributable to in-flight turbulence. Traditionally associated with automobile crashes and diving headfirst into shallow pools, the axial load results in a compressive force to the atlas and subsequent lateral separation of the two halves of the C1 vertebral ring. The purpose of this case study is to alert providers, aircraft personnel, and passengers of the inherent risk of air travel and the importance of wearing a seatbelt at all times, describe the signs and symptoms of this often-overlooked fracture, and provide general treatment guidelines based on radiographic assessments of fracture stability.

Atlas Fractures: Diagnosis, Current Treatment Recommendations, and Implications for Elderly Patients

Fractures of the C1 vertebrae (atlas) are commonly the result of falls and other trauma, which cause hyperextension, or axial compression of the cervical spine. Although historically thought as a benign injury with lower neurological risks, current data suggests that this may not hold true for geriatric patients (aged 65 y and older) who may be predisposed to these fractures even after lower-energy trauma such as ground-level falls. Advancements in orthopedic trauma care has increased our diagnostic abilities to identify and manage patients with C1 fractures and other upper cervical spine trauma. However, there are no universal treatment guidelines based on level I trials. Current treatment ranges from nonoperative to operative management depending on fracture-pattern and integrity of the surrounding ligaments. Furthermore, in the elderly patients these fractures present a unique dilemma due to preexisting comorbidities and contraindications to various treatment modalities. C1 fractures warrant greater recognition to provide optimal treatment to patients and minimize the risk for developing complications. The goal of this review is to highlight the most updated treatment guidelines and to discuss the complications of both operative and nonoperative management of C1 fractures especially among the elderly patient population.

Local delivery of HMGB1 in gelatin sponge scaffolds combined with mesenchymal stem cell sheets to accelerate fracture healing

Fracture nonunion and delayed union continue to pose challenges for orthopedic surgeons. In the present study, we combined HMGB1 gelatin sponges with MSC sheets to promote bone healing after surgical treatment of rat tibial fractures. The HMGB1 gelatin sponge scaffolds supported the expansion of mesenchymal stem cells (MSCs) and promoted the osteogenic differentiation of MSCs and MSC sheets. Lentiviral vectors were then used to overexpress HMGB1 in MSCs. The results indicated that HMGB1 promotes the osteogenic differentiation of MSCs through the STAT3 pathway. Both siRNA and a STAT3 inhibitor downregulated STAT3, further confirming that HMGB1 induces the osteogenic differentiation of MSCs partly via the STAT3 signal pathway. In a rat tibial osteotomy model, we demonstrated the ability of HMGB1 gelatin sponge scaffolds to increase bone formation. The addition of MSC sheets further enhanced fracture healing. These findings support the use of HMGB1-loaded gelatin sponge scaffolds combined with MSC sheets to enhance fracture healing after surgical intervention.

Unstable C1 Fracture Managed with Internal Fixation Using Lateral Mass Screws: A Case Report

CASE

A 47-year-old woman presented with an unstable C1 fracture after falling down several stairs. She was found to have a sagittal split fracture of the right C1 lateral mass extending into the posterior arch. The fracture was treated with a direct posterior osteosynthesis of C1 using lateral mass screws.

CONCLUSION

Surgical management of unstable C1 fractures has traditionally involved posterior fusion of C1 to C2 or fusion from the occiput to C2. These fusion procedures can be quite functionally limiting. Recently, direct osteosynthesis of C1 has been shown to be an effective, motion-preserving alternative.

Transoral screw and wire fixation for unstable anterior ½ atlas fracture

Study Design:

Atlas fractures are evaluated according to the fracture type and ligamentous injury. External immobilization may result in fracture nonunion.

Objective:

The ideal treatment method for non-stabilized atlas fractures is limited fixation without restricting the range of motion of the atlantoaxial and atlantooccipital joints.

Summary of Background Data:

Such a result can be established by using either anterior fixation or posterior lateral mass fixation. However, none of these techniques can fully address anterior 1/2 atlas fractures such as in this case.

Materials and Methods:

A transoral technique in which bilateral screws were placed intralaminarly and connected with wire was used to reduce and stabilize an anterior 1/2 fracture of C1.

Result:

Radiological studies after the surgery showed good cervical alignment, no screw or wire failure and good reduction with fusion of anterior arcus of C1.

Conclusions:

Internal immobilization by this screw and wire osteosynthesis technique protects the mobility of the atlanto-occipital and atlantoaxial joints. The main advantage is that neither the twisted wires inserted under the anterior lamina, nor the laterally placed screw heads interfere with midline wound closure; unlike the plate/cage and rod systems used together with anterior screws. A computer navigation system with intraoperative 3D imaging facilities will be of benefit for safe placement of the screw, however we preferred a free-hand technique, as the starting point was at the fracture line along the trajectory of the routinely accessible anterior lamina.

Unilateral lag screw fixation of isolated non-union atlas lateral mass fracture: a new technical note

We describe a novel and new technique of posterior unilateral lag screw fixation of non-union atlas lateral mass fracture. A 46-year-old man presented with cervical pain and tenderness after a vehicle turn over accident and he was diagnosed to have left atlas lateral mass fracture. He was initially treated by immobilization using Minerva orthosis. About 2 months later, he developed severe neck pain and limitation of motion and thus he was scheduled for operation due to non-union atlas lateral mass fracture. A 28 mm lag screw was inserted under anterior-posterior and lateral fluoroscopic views. The entrance point was at the dorsal aspect of left atlas posterior arc at its junction to the lateral mass, and by using the trajectory of 10 degrees medial and 22 degrees cephalad fracture reduction was achieved. Unilateral lag screw fixation of atlas fractures is an appropriate, safe and effective surgical technique for the management of unilateral atlas fractures.

Posterior osteosynthesis with monoaxial lateral mass screw-rod system for unstable C1 burst fractures

BACKGROUND CONTEXT

Surgical treatment for unstable atlas fractures has evolved in recent decades from C1-C2 or C0-C2 fusion to motion-preservation techniques of open reduction and internal fixation (ORIF). However, regardless of a transoral or a posterior approach, the reduction is still not satisfactory.

PURPOSE

The article describes and evaluates a new technique for treating unstable atlas fractures by using a monoaxial screw-rod system.

STUDY DESIGN

This is a retrospective study.

PATIENT SAMPLE

The sample includes adult patients with unstable C1 fractures treated with a posterior monoaxial screw-rod system.

OUTCOME MEASURES

The outcome measures included a visual analog pain scale, radiographic reduction (lateral mass displacement [LMD]), maintenance of reduction, C1-C2 instability (anterior atlantodens interval), and complications.

MATERIALS AND METHODS

From August 2013 to May 2016, nine consecutive patients with unstable atlas fractures were retrospectively reviewed. All patients were treated with posterior ORIF by using a monoaxial screw-rod system. The medical records and the preoperative and postoperative radiographs were reviewed. Preoperative and postoperative computed tomography scans were used to specify the fracture types and to assess the reduction.

RESULTS

All nine patients with a mean age of 50.3 years successfully underwent surgery with this technique, and a follow-up of 17.4±9.3 months was performed. Transverse atlantal ligament (TAL) injury was found in eight of the nine patients: one of type I and seven of type II. The preoperative LMD averaged 7.0±2.2 mm and was restored completely after surgery; all the fractures achieved bony healing without loss of reduction or implant failure. None of the patients had complications of neurologic deficit, vertebral artery injury, or wound infection associated with the surgical procedure. Two patients complained of greater occipital nerve neuralgia after the operation, which gradually disappeared in 1 month. All patients had a well-preserved range of motion of the upper cervical spine at the final follow-up.

CONCLUSIONS

Posterior osteosynthesis with a monoaxial screw-rod system is capable of an almost anatomical reduction for the unstable atlas fractures. The TAL incompetence may not be a contraindication to ORIF for C1 fractures, but the long-term effect of C1-C2 instability remains to be further investigated.

Atlas Fractures and Atlas Osteosynthesis: A Comprehensive Narrative Review

Most atlas fractures are the result of compression forces. They are often combined with fractures of the axis and especially with the odontoid process. Multiple classification systems for atlas fractures have been described. For an adequate diagnosis, a computed tomography is mandatory. To distinguish between stable and unstable atlas injury, it is necessary to evaluate the integrity of the transverse atlantal ligament (TAL) by magnetic resonance imaging and to classify the TAL lesion. Studies comparing conservative and operative management of unstable atlas fractures are unfortunately not available in the literature; neither are studies comparing different operative treatment strategies. Hence all treatment recommendations are based on low level evidence. Most of atlas fractures are stable and will be successfully managed by immobilization in a soft/hard collar. Unstable atlas fractures may be treated conservatively by halo-fixation, but nowadays more and more surgeons prefer surgery because of the potential discomfort and complications of halo-traction. Atlas fractures with a midsubstance ligamentous disruption of TAL or severe bony ligamentous avulsion can be treated by a C1/2 fusion. Unstable atlas fractures with moderate bony ligamentous avulsion may be treated by atlas osteosynthesis. Although the evidence for the different treatment strategies of atlas fractures is low, atlas osteosynthesis has the potential to change treatment philosophies. The reasons for this are described in this review.

Optimal Entry Point and Trajectory for Anterior C1 Lateral Mass Screw

STUDY DESIGN

A radiographic analysis of the anatomy of the C1 lateral mass using computed tomography (CT) scans and Mimics software.

OBJECTIVE

To define the anatomy of the C1 lateral mass and make recommendations for optimal entry point and trajectory for anterior C1 lateral mass screws.

SUMMARY OF BACKGROUND DATA

Although various posterior insertion angles and entry points for screw insertion have been proposed for posterior C1 lateral mass screws, no large series have been performed to assess the ideal entry point and optimal trajectory for anterior C1 lateral mass screw placement.

MATERIALS AND METHODS

The C1 lateral mass was evaluated using CT scans and a 3-dimensional imaging application (Mimics software). Measuring the space available for the anterior C1 lateral mass screw (SAS) at different camber angles from 0 to 30 degrees (5-degree intervals) was performed to identify the ideal camber angle of insertion. Measuring the range of sagittal angles was performed to calculate the ideal sagittal angle. Other measurements involving the height of the C1 lateral mass were also made.

RESULTS

The optimal screw entry point was found to be located on the anterior surface of the atlas 12.88 mm (±1.10 mm) lateral to the center of the anterior tubercle. This optimal entry point was found to be 6.81 mm (±0.59 mm) superior to the anterior edge of the atlas inferior articulating process. The mean ideal camber angle was 20.92 degrees laterally and the mean ideal sagittal angle was 5.80 degrees downward.

CONCLUSIONS

These measurements define the optimal entry point and trajectory for anterior C1 lateral mass screws and facilitate anterior C1 lateral mass screw placement. A thorough understanding of the local anatomy may decrease the risk of injury to the spinal cord, vertebral artery, and internal carotid artery. Delineating the anatomy in each case with preoperative 3D CT evaluation is recommended.

Posterior arthrodesis of C1-C3 for the stabilization of multiple unstable upper cervical fractures with spinal cord compromise: A case report and literature review

BACKGROUND

Multiple fractures of the atlas and axis are rare. The management of multiple fragment axis fractures and unstable atlas fractures is still challenging for the spinal surgeon. There are no published reports of similar fractures with 3-part fracture of axis associated with an unstable atlas fracture.

CASE SUMMARY

We present a patient with concurrent axis and atlas fractures, which have not been reported. The patient suffered hyperextension injury with neck pain and numbness of the bilateral upper extremity associated with weakness after a 2-m fall. The axis fractures included an odontoid type IIA fracture and traumatic spondylolisthesis of C2-C3. The atlas fracture was unstable. The neurological examination manifested as central canal syndrome, which was due to the hyperextension injury of cervical spine and spondylolisthesis of C2-C3. The patient was diagnosed as multiple unstable upper cervical fractures with spinal cord compromise. We performed posterior arthrodesis of C1-C3. Postoperatively, the patient showed neurological improvement, and C1-C3 had fused at the 3-month follow-up.

CONCLUSION

Posterior arthrodesis of C1-C3 could provide a stable fixation for the 3 parts of axis (an odontoid type IIA fracture and traumatic spondylolisthesis of C2-C3) combined an unstable atlas fracture. Both the patient and the doctor were satisfied with the results of the treatment. So posterior arthrodesis of C1-C3 is a suitable treatment option for the treatment of a concurrent unstable atlas fracture and multiple fractures of the axis.

Reduction and ring fixation of instable C1 fractures with monoaxial pedicle screws

INTRODUCTION

Ring fixation of C1 can be performed using pedicle screws and a rod in case of unstable Jefferson or lateral mass fractures of C1.

MATERIALS AND METHODS

In a case series of three patients, we stabilized C1 fractures surgically using a modified technique of C1 ring fixation by using monoaxial instead of polyaxial screws. Functional outcome and pain was recorded postoperatively.

RESULTS

In this very small case series, we observed good results concerning pain and functional outcome. All fractures were bony healed within 13 weeks. In one case, a screw penetrated the spinal canal and had to be repositioned. A mild irritation of C2 nerve root occurred in two cases postoperatively.

CONCLUSION

C1 Ring fusion with monoaxial screws provides a good ability to reduce the fracture indirectly by the screws and the rod itself.

Solitary C1 Posterior Fixation for Unstable Isolated Atlas Fractures: Case Report and Systematic Review of the Literature

Study Design A systematic review of the literature. Objectives To review the published results to date of motion-preserving direct reconstruction of C1 ring fractures with combined coronal plane displacement of at least 7 mm (rule of Spence) and so at risk for Dickman type I or II disruption of the transverse atlantal ligament (TAL). Methods A structured literature review prompted by successful management of a typical case. Results To date only 65 such cases are reported and follow-up is almost uniformly short. Although reported clinical success is uniform, the case mix is heterogenous and confirmation/classification of ligamentous injury at baseline is often lacking. Conclusions Direct C1 stabilization shows promise as a "more selective" option in managing displaced atlas fractures with probable TAL disruption but cannot yet be recommended as a practice standard. Prospective clinical studies are indicated and should be structured so as to differentiate between Dickman type I and type II injuries of the TAL.

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.

Radiographic and clinical assessment on the accuracy and complications of C1 anterior lateral mass and C2 anterior pedicle screw placement in the TARP-III procedure: a study of 106 patients

PURPOSE

To investigate the (1) radiographic and clinical accuracy of C1 anterior lateral mass screw (C1ALMS) and C2 anterior pedicle screw (C2APS) placement in the transoral atlantoaxial reduction plate (TARP)-III procedure, (2) screw insertion-associated clinical complications and (3) fusion status between C1 and C2.

METHODS

Radiographic and clinical data were obtained from the electronic medical record system. Studies were carried out to assess the accuracy of C1ALMS and C2APS placement, the screw insertion-associated clinical complications and the fusion status between C1 and C2. Placement of the screws was assessed using the modified All India Institute of Medical Sciences outcome-based classification.

RESULTS

Two-hundred and twelve C1ALMS and 207 C2APS in 106 patients were assessed. The ideal accurate rates were 92.0% (195) and 53.1% (110), and the acceptable accurate rates were 97.6% (207) and 87.0% (180), respectively. One patient died postoperatively due to C2 screw misplacement. There were no symptoms of neurologic and vertebral artery injuries in the rest of the patients. 102 patients (97.1%) achieved solid fusion between C1 and C2. No instrumentation failure due to delayed union or nonunion was observed.

CONCLUSION

C1ALMS placement in TARP-III procedures appears to be safe. The cortical breach rate of C2APS is high though clinically the neurovascular complication rate is similar to that of posterior atlantoaxial procedures. Advanced navigation strategies may help improve the accuracy of C2APS placement and decrease potential complications.