Posterior osteosynthesis with a new self-designed lateral mass screw-plate system for unstable atlas burst fractures.

BACKGROUND: In the treatment of unstable atlas fractures using the combined anterior-posterior approach or the posterior monoaxial screw-rod system, factors such as severe trauma or complex surgical procedures still need to be improved despite the favourable reduction effect. This research described and evaluated a new technique for the treatment of unstable atlas fracture using a self-designed lateral mass screw-plate system. METHODS: A total of 10 patients with unstable atlas fractures using this new screw-plate system from January 2019 to December 2021 were retrospectively reviewed. All patients underwent posterior open reduction and internal fixation (ORIF) with a self-designed screw-plate system. The medical records and radiographs before and after surgery were noted. Preoperative and postoperative CT scans were used to determine the type of fracture and evaluate the reduction of fracture. RESULTS: All 10 patients were successfully operated with this new system, with an average follow-up of 16.7 ± 9.6 months. A total of 10 plates were placed, and all 20 screws were inserted into the atlas lateral masses. The mean operating time was 108.7 ± 20.1 min and the average estimated blood loss was 98.0 ± 41.3 ml. The lateral mass displacement (LMD) averaged 7.1 ± 1.9 mm before surgery and almost achieved satisfactory reduction after surgery. All the fractures achieved bony healing without reduction loss or implant failure. No complications (vertebral artery injury, neurologic deficit, or wound infection) occurred in these 10 patients. At the final follow-up, the anterior atlantodens interval (AADI) was 2.3 ± 0.8 mm and the visual analog scale (VAS) was 0.6 ± 0.7 on average. All patients preserved almost full range of motion of the upper cervical spine and achieved a good clinical outcome at the last follow-up. CONCLUSIONS: Posterior osteosynthesis with this new screw-plate system can provide a new therapeutic strategy for unstable atlas fractures with simple and almost satisfactory reduction.

The internal carotid artery and the atlas: anatomical relationship and implications for C1 lateral mass fixation.

PURPOSE: The internal carotid artery (ICA) is potentially at risk during posterior fixation of C1. In this study, we performed a CT-based anatomical analysis of the relationship between the internal carotid artery and the lateral mass of the atlas. METHODS: We analysed 30 CT angiography of the cervical spine, and we measured on both sides the distance of the carotid artery from the midline, distance of the ICA from the anterior cortex of C1 and from the ideal C1 screw entry point. We measured the angle between the sagittal plane passing through the entry point and the tangent line of the vessel. Separated statistical analysis between left and right sides, between male and female patients, and differentiation by age were also performed. RESULTS: Sixty ICAs were studied. The mean distance of the ICA from the midline was 23.3 ± 4.3 mm, with a minimum of 15 mm. The distance between the ICA and the anterior cortical layer of C1 was 4.8 ± 2.7 mm, with a minimum of 1.1 mm. The distance between the screw entry point and the arterial wall was 22.6 ± 2.8 mm, with a minimum of 17.5 mm. The mean angle was 10.4°, with a minimum of 11°. CONCLUSIONS: Although rare, intraoperative lesion of the ICA is reported and the spine surgeon must be aware of this risk. Careful preoperative planning is mandatory and the position of the ICA in relation to C1 must be assessed. The anatomical parameters presented in this paper can be useful to reduce the risk of ICA injury.

[Ventral decompression techniques in patients with traumatic and non-traumatic atlanto-axial dislocations]. / Metody ventral'noi dekompressii u patsientov s atlanto-aksial'nymi dislokatsiiami travmaticheskogo i netravmaticheskogo geneza.

Compression of the caudal medulla oblongata and ventral portions of the spinal cord is the most dangerous complication of atlanto-axial dislocation (AAD). AIM: The study objective was to improve surgical management of patients with ventral compression of the spinal cord in the setting of AAD of various genesis. MATERIAL AND METHODS: We analyzed treatment outcomes in 250 patients with C1 and C2 injuries and diseases for the period between 2002 and 2016. Persistent ventral compression of the neural structures in the setting of AAD was detected in 34 (13.6%) patients. Anterior or posterior dislocation was in 21 patients, vertical dislocation occurred in 7 patients, and mixed (anterior and vertical) occurred in 6 cases. The causes of AAD included odontoid fractures (21 patients, 61.8%), Jefferson fractures (6 patients, 17.6%), atlas transverse ligament rupture (1 patient, 2.9%), rheumatoid arthritis (4 patients, 11.8%), and nonspecific spondylitis (2 patients, 5.9%). RESULTS: All dislocations were divided into Halo-tractable and Halo-intractable ones. In 24 cases, ventral decompression was achieved due to Halo reposition. Additional resection of a compressing substrate was performed through the submandibular approach in 4 patients, through the transoral approach in 5 patients, and through the transnasal approach in 1 case. In the postoperative period, complications in the form of pharyngeal edema developed in 1 patient after transoral decompression. In the other cases, there were no postoperative complications. All patients had improvement in their condition in the form of regression of a neurological deficit. CONCLUSION: Halo reposition is a technique eliminating, completely or partially, ventral compression in certain traumatic and non-traumatic dislocations. The choice of a surgical corridor should be performed after preliminary Halo correction. If the nasopalatine line runs in the odontoid neck projection, the submandibular approach may be used in the case of a Halo-tractable dislocation, and the endonasal approach may be used in the case of a Halo-intractable dislocation.

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.

Use of Intraoperative Imaging to Preserve C1-C2 Mobility in Complex Atlas-Hangman Fractures.

Background: Combination fractures of the C1-C2 complex especially atlas and hangman are relatively uncommon and management usually compromises C1-C2 mobility. Objective: To evaluate the treatment of combined C1- hangman's fracture with and without intraoperative O- arm based navigation system, and its outcome in terms of preserving C1-C2 mobility. Methods: This was a case series of patients with combined C1 and hangman's fracture, managed at a tertiary care hospital during February 2009 to December 2016. Neurological function assessed with American Spine Injury Association (ASIA) impairment scale. Radiological fusion of the operated segment assessed with computed tomographic scan, criteria used for successful fusion included formation of callus across the fracture. Preservation of rotational motion between C1 and C2 was assessed by cervical flexion rotation (CFR) test. Results: We included 10 patients (male/female: 9/1; mean 47.7 ± 17.5 years) in our study. Operative intervention was performed in 9 patients. We used intraoperative computed tomogram (CT) scan with navigation in 5 patients. The mean follow-up period was 28.7 months (range 6 to 70 months). Neurological recovery occurred in all 4 patients with preoperative neurological deficits. Radiological fusion occurred in all cases. Rotation at C1-2 was preserved in all 5 cases operated under O-arm guidance and in one patient with type 1 fracture who was managed conservatively. Conclusions: The goals in treating these complex fractures are to achieve early maximum stability and preserving maximum range of motion. These are often competing phenomena, which can be achieved by using intra operative CT scan and navigation system.

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.

Surgically Treated C1 Fractures: A Population-Based Study.

OBJECTIVE: To characterize surgical treatment and outcomes of C1 fractures in a population-based setup. METHODS: Patients with C1 fracture treated at Kuopio University Hospital Neurosurgery were retrospectively identified from January 1996 to June 2017. C1 fractures were classified according to the AO Spine Upper Cervical and Gehweiler classification systems. Patients were divided into 4 groups based on their treatment: group 1 (underwent C1 surgery as a primary option), group 2 (underwent C1 surgery as a secondary option after initial nonoperative treatment), group 3 (underwent surgery involving the C1 level with main indication being a concomitant cervical spine fracture), and group 4 (C1 fracture treatment was nonoperative). RESULTS: We identified 47 patients with C1 fracture (mean age, 60.3 ± 18.2 years; 83.0% men; American Society of Anesthesiologists score, 2.3 ± 0.8). Concomitant cervical spine fractures were present in 89.4% of cases, most commonly in the C2 vertebra (75.4%). In group 2, 3 of 5 fractures changed from AO Spine type A to B in control imaging after nonoperative treatment, indicating fracture instability and requiring secondary surgery. Good C1 fracture alignment was achieved for 10 of 10 followed-up patients in groups 1 and 2, and for 10 of 11 followed-up patients in group 3. Residual neck pain and stiffness were present in all groups. Neurologic symptoms were rare and mild. CONCLUSIONS: For unstable C1 fractures, surgery is safe treatment with good outcomes. Fractures initially determined as stable may require surgery if alignment is worsened in follow-up imaging. Magnetic resonance imaging is recommended to better detect unstable C1 fractures in diagnostic imaging.

Unilateral C1 split fracture osteosynthesis using a patient-specific three-dimensional-printed guide: Technique report.

Split-type C1 lateral mass fractures have a propensity for progressive fracture displacement. Since almost all cases end up showing progressive fragment diastasis, many authors recommend early surgical treatment. However, placing a C1 lag screw through a C1 split fracture is a challenging task. To overcome this, we designed a patient-custom three-dimensional (3D)-printed guide plate. We present the case of a 57-year-old female patient with a C1 lateral mass split fracture. Considering the amount of fragment translation, primary osteosynthesis was proposed. To purchase both fragments, placement of a lag screw was assisted intraoperatively by a custom 3D-printed composite guide plate, which enabled us to accurately place the screw. After an uneventful procedure, the patient was discharged from hospital after 72 h. Computed tomography scan performed at 12 months showed good fracture consolidation. The use of a patient-specific guide to place a lag screw through a split fracture of the atlas proved to be a safe, accurate, and inexpensive alternative to intraoperative imaging integrated with image-guided surgery.

Horizontal fracture of the atlas - A rare but unstable C1 fracture.

Horizontal fractures of the atlas are uncommon fractures associated with instability of the craniocervical junction. Most commonly associated with high-speed motor vehicle accidents, these fractures need to be identified and treated appropriately. Due to its relatively benign presentation on bony imaging, magnetic resonance imaging to look for ligamentous instability is important. We present two such cases which were managed by occipitocervical fusion at our institute.

Direct Fixation of C1 Jefferson Fracture Using C1 Lateral Mass Screws: A Case Report.

BACKGROUND: Jefferson fractures are classically described as burst fractures of C1. Traditional surgical treatment of these unstable fractures is either occipito-cervical or posterior C1-C2 fusion, resulting in a significant loss of range of cervical neck movement. This case report discusses the fixation of a Jefferson fracture using C1 lateral mass screws to achieve surgical stabilization while preserving the range of movement. We aim to add to the body of evidence supporting this fixation method. METHODS: A 39-year-old male presented to our emergency department with an unstable Jefferson fracture caused by trauma. The various treatment options, such as cervical collar, HALO immobilization, occipito-cervical fusion, and atlanto-axial fusion and direct fixation of C1, were evaluated and discussed with the patient. Informed consent was obtained from the patient prior to writing this case report. RESULTS: At 3 months postoperation, the patient demonstrated near full range of movement in his neck. He had also resumed driving. By 6 months, the patient returned to work, and at 12 months, imaging confirmed union. CONCLUSIONS: This case report adds to the body of evidence supporting the technique of C1 lateral mass screws for direct stable fixation of Jefferson fractures. This fixation method preserves the cervical spine range of motion with minimal functional restriction.

Atlas Fracture with Concomitant Vertebral Artery Hypoplasia, a Rare but Potentially Hazardous Combination: A Case Report.

The fractures of the first cervical spine vertebrae (atlas) represent 7% of all the overall cervical spine fractures. Hypoplasia of the vertebral artery is also rare (10% of the general population), but even rarer is the combination of those both conditions. This combination should always be identified and treated because sometimes it can be extremely dangerous for the patient. We present a case of a 24-year-old patient who suffered an atlas fracture with concomitant vertebral artery hypoplasia (VAH). We also present the diagnostic algorithm and the treatment management that we have followed. In case of cervical spine trauma the neurovascular symptoms should not be underestimated. Any neurological symptom (sensory, motor, reflex deficits) should be evaluated in detail. In some cases, with uncommon neurological symptoms such as, in our case, unilateral headache, dizziness and vertigo (or generally, involuntary eye movements and salivation, impaired speech and hearing, diplopia, blur vision, incoordination, imbalance, limb weakness) head injury or vertebral artery (VA) injuries have to be suspected. Further evaluation with brain computed tomography (CT) scan and computed tomography angiography (CTA) should be provided. In case of cervical spine trauma over a pre-existing VAH the complications rate is even higher and the early diagnosis and treatment are crucial.

C1 fracture: Analysis of consolidation and complications rates in a prospective multicenter series.

INTRODUCTION: Three types of C1 fracture have been described, according to location: type 1 (anterior or posterior arc), type 2 (Jefferson: anterior and posterior arc), and type 3 (lateral mass). Stability depends on transverse ligament integrity. The main aim of the present study was to analyze complications and consolidation rates according to fracture type, age and treatment. MATERIAL AND METHODS: The French Society of Spinal Surgery (SFCR) performed a multicenter prospective study on C1-C2 trauma. All patients with recent fracture diagnosed on CT were included. Consolidation on CT was studied at 3 months and 1 year. Medical, neurologic, infectious and mechanical complications were inventoried using the KEOPS data-base. RESULTS: Sixty-three of the 417 patients (15.1%) had C1 fracture: type 1 (33.3%), type 2 (38.1%), or type 3 (28.6%). The transverse ligament was intact in 53.9% of cases. Treatment was non-operative in 63.5% of cases, surgical in 27.0%, and surgical after failure of non-operative treatment in 9.5%. There were 8 medical complications, more frequently in patients aged >70 years, following surgery (p<0.0001). The consolidation rate was 84.2% with non-operative treatment, 100% for primary surgery, and 33.3% for secondary surgery (p=0.002). There were 10 cases of non-union, in 4.8% of type 1, 13.6% of type 2 and 33.3% of type 3 fractures (p=0.001). CONCLUSION: Medical complications showed association with age and with type of treatment. Non-operative treatment was suited to types 1, 2 and 3 with minimal displacement and intact transverse ligament. C1-C2 fusion was suited to displaced unstable type 2 fracture. Displaced type 3 fracture incurred risk of non-union. Early surgery may be recommended. LEVEL OF EVIDENCE: III.

Variations in treatment of C1 fractures by time, age, and geographic region in the United States: An analysis of 985 patients.

The purpose of this investigation was to evaluate the variations in the treatment of C1 fractures over time, by age group, and by geographic region using a nationwide database. The Nationwide Emergency Department Sample (NEDS) database was queried to identify patients ≥18 years who sustained C1 fracture from 2006-2012. Patients were filtered based on the intervention they received: collar, halo, or surgery. Regions of hospital used in analysis were defined as Northeast, Midwest, South, and West. Surgical intervention for C1 fracture increased from 27.1% of cases in 2006 to 55.4% of cases in 2012 (P<0.001). The rate of collar treatment increased with increasing age. In contrast, rate of halo use decreased with increasing age. A greater proportion of patients in the Northeast were treated by collar compared to all other regions (P<0.001). We can conclude that there is considerable variation in the treatment of C1 fractures with regards to age and geographic region. Surgical treatment of these fractures is increasing over time. Future considerations should be given to developing treatment guidelines to decrease variation and potentially create cost-savings.

Unilateral C1 Sagittal Split Fractures: An Unusual Entity Revisited.

BACKGROUND: An isolated, unilateral fracture of the C1 lateral mass is a rare condition that has been only minimally described in the literature. Historically, these fractures have predominantly been managed conservatively with either external immobilization or traction. CASE DESCRIPTION: We review the literature and present 2 patients that presented after failing conservative management, but demonstrated excellent clinical outcomes after surgical treatment. CONCLUSIONS: After failure of conservative management, unilateral sagittal split fractures may be safely and effectively managed with unilateral open reduction and placement of a lag screw.

C1 Lateral Mass Displacement and Transverse Atlantal Ligament Failure in Jefferson's Fracture: A Biomechanical Study of the "Rule of Spence".

BACKGROUND: Jefferson's fracture, first described in 1927, represents a bursting fracture of the C1 ring with lateral displacement of the lateral masses. It has been determined that if the total lateral mass displacement (LMD) exceeds 6.9 mm, there is high likelihood of transverse atlantal ligament (TAL) rupture, and if LMD is less than 5.7 mm TAL injury is unlikely. Several recent radiographic studies have questioned the accuracy and validity of the "rule of Spence" and it lacks biomechanical support. OBJECTIVE: To determine the amount of LMD necessary for TAL failure using modern biomechanical techniques. METHODS: Using a universal material testing machine, cadaveric TALs were stretched laterally until failure. A high-resolution, high-speed camera was utilized to measure the displacement of the lateral masses upon TAL failure. RESULTS: Eleven cadaveric specimens were tested (n = 11). The average LMD upon TAL failure was 3.2 mm (±1.2 mm). The average force required to cause failure of the TAL was 242 N (±82 N). From our data analysis, if LMD exceeds 3.8 mm, there is high probability of TAL failure. CONCLUSION: Our findings suggest that although the rule of Spence is a conceptually valid measure of TAL integrity, TAL failure occurs at a significantly lower value than previously reported (P < .001). Based on our literature review and findings, LMD is not a reliable independent indicator for TAL failure and should be used as an adjunctive tool to magnetic resonance imaging rather an absolute rule.

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.

Conservative management of craniovertebral junction injuries: Still a good option.

BACKGROUND: Injuries to the craniovertebral junction (CVJ) are not uncommon, and are among the few skeletal injuries that carry a high mortality rate. Successful management of these injuries depends on familiarity with the normal anatomic relationships of this region, as well as prudent decision making regarding surgical versus conservative management alternatives. METHODS: The purpose of this study was to analyze the indications for conservative treatment of CVJ trauma and to analyze the outcomes. RESULTS: Eighty-eight patients admitted with CVJ injuries were managed conservatively. More than half were nearly neurologically intact on admission; 91% improved whereas 80% (excluding deaths/lost to follow) ultimately achieved bony union without surgical intervention. CONCLUSION: This study documents that conservative management of CVJ injuries in a select population can yield good clinical results.

A retrospective review of fixation of C1 ring fractures--does the transverse atlantal ligament (TAL) really matter?

BACKGROUND CONTEXT: In contrast to the majority of outcome data, many consider C1 fractures to be benign injuries and so have advocated for conservative management, except in the case of concomitant transverse atlantal ligament (TAL) injury where C1-C2 or occiput-C2 fusions are recommended. PURPOSE: Our goal was to evaluate a series of unstable C1 fractures treated with C1 open reduction and internal fixation (ORIF) to assess clinical and radiographic outcomes by determining the success of reduction and pain relief. STUDY DESIGN/SETTING: This is a retrospective cohort review. PATIENT SAMPLE: The sample includes adult patients with unstable C1 fractures treated with open reduction and primary internal fixation. OUTCOME MEASURES: Primary outcome measures included visual analog pain scale (VAS), radiographic reduction (lateral mass displacement), maintenance of reduction, C1-C2 instability, and complications. METHODS: A retrospective review of all patients with C1 fractures between September 2002 and September 2013 identified 12 consecutive patients from a level I trauma center who were treated with primary internal fixation without fusion. Electronic medical records and preoperative and postoperative radiographs were reviewed. The surgical technique consisted of a posterior cervical approach to the C1 arch and open reduction using bilateral C1 lateral mass screws connected transversely with a rod. Pre- and postoperative computed tomography scans were used to assess reduction. Long-term follow-up flexion and extension radiographs were used to assess C1-C2 stability. The authors did not receive relevant funding in relation to this research. RESULTS: Twelve patients underwent C1 ORIF, with a mean age of 43 (9 males and 3 females) and a mean follow-up of 17 months. Transverse atlantal ligament was found to be disrupted with type I or type II injury in 11 of the 12 patients: 5 type I and 6 type II. Preoperative lateral mass displacement averaged 7.1 mm, with postoperative displacement after reduction averaging 2.4 mm (p-value <.001). The VAS score averaged 0.7 at latest follow-up. No patients went on to develop C1-C2 instability on final flexion-extension films. No patients had a complication that resulted in neurologic deficit or vascular injury associated with the procedure. No patients were found to have late sequelae of malunion or loss of reduction. Two surgically related complications occurred, namely one patient with errant screw requiring return to the operating room (OR) and one with arthrosis of the occipital-C1 joint. CONCLUSIONS: Although a small series, early evidence suggests that patients with unstable C1 ring fractures can be successfully managed with primary ORIF. Open reduction and internal fixation results in a stable construct that maintains reduction, results in excellent pain control, and does not lead to C1-C2 instability. In our series, we have not observed the presence of TAL injury to adversely affect outcomes, and thus do not believe it is a contraindication to ORIF. Comparative studies comparing internal fixation with non-operative, C1-C2, or occiput-C2 fusions would yield more insight into optimal treatment options for these fractures.