Axis fractures

Anterior atlantoaxial motion preservation fixation technique for axis complex fractures (odontoid process with Hangman's fractures) and technique notes

This study aims to investigate the feasibility and efficacy of anterior atlantoaxial motion preservation fixation (AMPF) in treating axis complex fractures involving the odontoid process fracture and Hangman's fractures with C2/3 instability. A retrospective study was conducted on eight patients who underwent AMPF for axis complex fractures at the General Hospital of Central Theater Command from February 2004 to October 2021. The types of axis injuries, reasons for injuries, surgery time, intraoperative blood loss, spinal cord injury classification (American Spinal Injury Association, ASIA), as well as complications and technical notes, were documented. This study included eight cases of type II Hangman's fracture, five cases of type II and three cases of type III odontoid process fracture. Five patients experienced traffic accidents, while three patients experienced falling injuries. All patients underwent AMPF surgery with an average intraoperative blood loss of 288.75 mL and a duration of 174.5 min. Two patients experienced dysphagia 1 month after surgery. The patients were followed up for an average of 15.63 months. One case improved from C to E in terms of neurological condition, three cases improved from D to E, and four cases remained at E. Bony fusion and Atlantoaxial Motion Preservation were successfully achieved for all eight patients. AMPF is a feasible and effective way for simultaneous odontoid process fracture and Hangman's fractures with C2/3 instability, while preserving atlantoaxial movement.

Odontoid Fracture as Proximal Junctional Failure in Patients With Multilevel Spine Fusions

STUDY DESIGN

Retrospective study.

OBJECTIVE

Proximal junctional failure (PJF) commonly occurs as a recognized potential outcome of fusion surgery. Here we describe a unique series of patients with multilevel spine fusion including the cervical spine, who developed PJF as an odontoid fracture.

METHODS

We performed a single site retrospective review of patients with prior fusion that included a cervical component, who presented with an odontoid fracture between 2012 and 2019. Radiographic measurements included C2-C7 SVA, C2-C7 lordosis, T1 slope, Occiput-C2 angle, proximal junctional kyphosis, and cervical mismatch. Associated fractures, medical comorbidities, and treatments were determined via chart review after IRB approval.

RESULTS

Nine patients met inclusion criteria. 5 reported trauma with subsequent onset of pain. All patients sustained a Type II odontoid fracture. 5 with associated C1/Jefferson fractures. In all patients, pre-injury Occiput-C2 angle was outside normative range; C2-C7 SVA was greater than 4 cm in 6 patients; T1-slope minus cervical lordosis was greater than 18.5 degrees in 6 patients. 7 patients were treated operatively with extension of fusion to C1 and 2 patients declined operative treatment.

CONCLUSION

In this series of 9 patients with multilevel fusion with type II odontoid fractures, all patients demonstrated abnormal pre-fracture sagittal alignment parameters and a greater than normal association of C1 fractures was noted. Further study is needed to establish the role of poor sagittal alignment with compensatory occiput-C2 angulation as a predisposing factor for odontoid fracture as a proximal junctional failure mechanism.

Analysis of the clinical characteristics and predisposing factors for neurological deficit with Hangman fractures

BACKGROUND

Hangman fracture is the second most common injury of the upper cervical spine, and neurological deficit with Hangman fracture is not rare. To our knowledge, few reports have statistically analyzed the predisposing factors for this injury. The objective of this study was to describe the clinical characteristics of neurological deficit associated with Hangman fracture and evaluate its risk factors.

METHODS

In this retrospective study, 97 patients with Hangman fractures were included. Data on the age, sex, injury etiology, neurological deficits, and associated injuries were obtained and evaluated. The pretreatment parameters, anterior translation and angulation of C2/3, presence of the posterior vertebral wall (PVW) fractures of C2, and presence of spinal cord signal changes were measured. Twenty-three patients with neurological deficits after Hangman fractures comprised group A, and 74 patients without neurological deficit comprised group B. Student's t-test or a nonparametric test and the chi-square test were used to evaluate the differences between groups. Binary logistic regression analysis was used to identify the risk factors for neurological deficit.

RESULTS

Among the 23 patients in group A, 2 were American Spinal Injury Association (ASIA) scale B, 6 were C, and 15 were D, and spinal cord magnetic resonance imaging signal change was observed at the level of C2-C3 disc, C2, or both. Patients with the combination of PVW fractures and ≥ 50% significant translation or angulation of C2/3 were significantly more likely to have a neurological deficit. Both factors remained significant in binary logistic regression analysis.

CONCLUSIONS

Neurological deficit after Hangman fractures always presents clinically as a partial neurological impairment. The combination of PVW fractures with ≥ 1.8 mm of translation or ≥ 5.5° of angulation of C2/3 was the predisposing factor for neurological deficit with Hangman fractures.

Fluoroscopy-Assisted C1-C2 Posterior Fixation for Atlantoaxial Instability: A Single-Center Case Series of 78 Patients

Background and Objectives: Posterior C1-C2 fixation, with trans-articular screws (TAS) or screw-rod-construct (SRC), is the main surgical technique for atlantoaxial instability, and can be performed with a fluoroscopy-assisted free-handed technique or 3D navigation. This study aimed to evaluate complications, radiological and functional outcome in patients treated with a fluoroscopy-assisted technique. Materials and Methods: A single-center consecutive cohort study was conducted of all adult patients who underwent posterior C1-C2 fixation, using TAS or CRS, between 2005-2019. Results: Seventy-eight patients were included, with a median follow-up time of 6.8 years. Trauma was the most common injury mechanism (64%), and cervicalgia the predominant preoperative symptom (88%). TAS was used in 33%, and SRC in 67% of cases. Surgery was associated with a significant reduction in cervicalgia (from 88% to 26%, p < 0.001). The most common complications were vertebral artery injury (n = 2, 2.6%), and screw malposition (n = 5, 6.7%, of which 2 were TAS and 3 were SRC). No patients deteriorated in their functional status following surgery. Conclusions: Fluoroscopy-assisted C1-C2 fixation with TAS or SRC is a safe and effective treatment for atlantoaxial instability, with a low complication rate, few surgical revisions, and pain relief in the majority of the cases.

Successful Nonsurgical Management of a Traumatic Dens Fracture in a Cat with Clinical and Radiographic Resolution

An adult domestic shorthair presented with obtundation, vestibular ataxia, head tilt, and visible evidence of facial injury following motor vehicle trauma. Plain radiographs and computed tomography imaging revealed a complete minimally displaced transverse fracture of the caudal aspect of the dens of the C2 vertebra and multiple minimally displaced cranial fractures. The dens fracture was managed with 8 wk of strict rest, followed by 4 wk of supervised activity at home. No external immobilization was performed. Neurological examinations at 8 days, 10 wk, and 9 mo following initial presentation were normal. Repeat radiographic and computed tomography examinations at 10 wk and 9 mo following the traumatic event demonstrated progressive and eventual complete osseous union of the fractured dens. To the authors’ knowledge, this is the first report of successful nonsurgical management of a traumatic dens fracture in an adult cat with documented radiographic and clinical resolution. This report suggests that nonsurgical management can be considered in such cats and that complete resolution with osseous union is feasible.

Management of fresh odontoid fractures using posterior C1-2 fixation without fusion: a long-term clinical follow-up study

OBJECTIVE

Posterior C1-2 fixation without fusion makes it possible to restore atlantoaxial motion after removing the implant, and it has been used as an alternative technique for odontoid fractures; however, the long-term efficacy of this technique remains uncertain. The purpose of the present study was to explore the long-term follow-up outcomes of patients with odontoid fractures who underwent posterior C1-2 fixation without fusion.

METHODS

A retrospective study was performed on 62 patients with type II/III fresh odontoid fractures who underwent posterior C1-2 fixation without fusion and were followed up for more than 5 years. The patients were divided into group A (23 patients with implant removal) and group B (39 patients without implant removal) based on whether they underwent a second surgery to remove the implant. The clinical outcomes were recorded and compared between the two groups. In group A, the range of motion (ROM) of C1-2 was calculated, and correlation analysis was performed to explore the factors that influence the ROM of C1-2.

RESULTS

A solid fracture fusion was found in all patients. At the final follow-up, no significant difference was found in visual analog scale score or American Spinal Injury Association Impairment Scale score between the two groups (p > 0.05), but patients in group A had a lower Neck Disability Index score and milder neck stiffness than did patients in group B (p < 0.05). In group A, 87.0% (20/23) of the patients had atlantoodontoid joint osteoarthritis at the final follow-up. In group A, the C1-2 ROM in rotation was 6.1° ± 4.5° at the final follow-up, whereas the C1-2 ROM in flexion-extension was 1.8° ± 1.2°. A negative correlation was found between the C1-2 ROM in rotation and the severity of tissue injury in the atlantoaxial region (r = -0.403, p = 0.024) and the degeneration of the atlantoodontoid joint (r = -0.586, p = 0.001).

CONCLUSIONS

Posterior C1-2 fixation without fusion can be used effectively for the management of fresh odontoid fractures. The removal of the implant can further improve the clinical efficacy, but satisfactory atlantoaxial motion cannot be maintained for a long time after implant removal. A surgeon should reconsider the contribution of posterior C1-2 fixation without fusion and secondary implant removal in preserving atlantoaxial mobility for patients with fresh odontoid fractures.

Wright's Technique with the Addition of Visualized Axial Cortical Windows in Odontoid Fractures

This study sought to investigate and evaluate a modified axial translaminar screw fixation for treating odontoid fractures. We performed a retrospective study at Wenzhou Medical University Affiliated Second Hospital between March 2016 and June 2018. We retrospectively collected and analyzed the medical records of 23 cases with odontoid fractures. All patients were identified as type II odontoid fractures without neurological deficiency and serious diseases following the classification of Anderson. The average age, gender ratio, and body mass index (BMI) were 54.3 ± 11.1 years, 12 men to 11 women, and 22.6 ± 2.4 kg/m² , respectively. Patients in this study accepted screw fixation using our modified axial translaminar screw fixation combined with atlas pedicle or lateral mass screw fixation. Within the technique, a small cortical "window" was dug in the middle of the axial contralateral lamina, such that the screws in the lamina were visualized to prevent incorrectly implanting the posterior spinal canal through the visualized "window." A total of 46 bone screws were accurately inserted into the axial lamina without using fluoroscopy. The length of all translaminar screws ranged between 26 and 30 mm, while the diameter was 3.5 mm. During the follow-up survey, the visual analog scale (VAS) and neck disability index (NDI) were measured. We provide a simple modification of Wright's elegant technique with the addition of "visualized windows" at the middle of the axial lamina. In all patients, screws were inserted accurately without bony breach and the screw angle was 56.1 ± 3.0°. Mean operative time was 102 ± 28 min with an average blood loss of 50 ± 25 mL. Postoperative hemoglobin and mean length of hospital stay were 12.0 ± 1.4 g/dL and 10.4 ± 3.4 days, respectively. The average follow-up time of all cases was 14.7 months and no internal fixation displacement, loosening, or breakage was found. All patients with odontoid fractures reported being satisfied with the treatment during the recheck period and good clinical outcomes were observed. At 1, 6, and 12 months, NDI and VAS showed that the symptoms of neck pain and limitations of functional disability improved significantly during follow-up. Our results suggest that the modified translaminar screw fixation technique can efficiently treat Anderson type II odontoid fracture, followed by the benefits of less soft tissue dissection, simple operation, no fluoroscopy, and accurate placement of screws.

C2-C3 Anterior Cervical Diskectomy and Fusion for Hangman's Fractures with C2 Posterior Dislocation: Technical Notes

BACKGROUND

The overwhelming majority of hangman's fractures cause anterior dislocation of C2. Hangman's fracture with C2 posterior dislocation is extremely rare; only 1 pediatric case was reported in 2018 to date. This kind of injury cannot be cataloged using current classification schemes, and no established treatment recommendations exist. The purpose of this article is to report a rare case of a hangman's fracture with C2 posterior dislocation, which does not fit into existing classification systems and discuss management technical notes to avoid pitfalls.

METHODS

We describe this case, review relevant literature, and share our experience.

RESULTS

A 31-year-old male sustained a hangman's fracture with C2 posterior dislocation after he fell into a 50-cm deep roadside ditch when riding a motorcycle. Radiograph and computed tomography on admission showed fractures through both pars of C2 and C2 posterior dislocation. Magnetic resonance imaging on admission showed high T2-weighted signal intensity of cervical spinal cord and compression of the cervical spinal cord by posterior dislocation of the C2 vertebral body. A C2-3 anterior cervical diskectomy and fusion was performed. At 6 months after operation, bony fusion was achieved and magnetic resonance imaging showed the T2-weighted signal hyperintensity of cervical spinal cord before surgery disappeared.

CONCLUSIONS

C2-C3 anterior cervical diskectomy and fusion is recommended for hangman's fractures with C2 posterior dislocation. Traction before surgery is not recommended.

Surgical Outcomes for C2 Tear Drop Fractures: Clinical Relevance to Hangman's Fracture and C2-3 Discoligamentous Injury

Objective

To analyze characteristics of surgically managed tear drop (TD) fractures of the C₂ axis associated with other injuries such as hangman's fracture and C_2‐3 discoligamentous injury as well as treatment outcomes.

Methods

A total of 14 patients (eight men and six women) with TD fractures of the C₂, who were surgically treated at four national trauma centers of tertiary university hospitals from January 2000 to December 2017, were included in this retrospective study. The mean age of the patients was 45.5 years (ranging from 19 to 74 years). The characteristics, surgical treatment methods (anterior fusion vs posterior fusion), and results of 14 TD fractures of the C₂ were analyzed retrospectively. And the clinical relevance between C₂ TD fracture and hangman's fracture and C_2‐3 discoligamentous injury was investigated through the co‐occurrence between injuries. The mean follow‐up time after surgery was 22.6 months (ranging from 12 to 60 months).

Results

Among 14 patients with TD fracture of the C₂, four patients (28.6%) had anterior TD fracture and 10 patients (71.4%) had posterior TD fracture. All 10 posterior TD fracture patients had anterior C_2‐3 displacement. While two of four anterior TD fracture patients had posterior C_2‐3 displacement, the remaining two did not. All 14 patients of TD fracture had at least two or more other associated C₂ injuries as well as C_2‐3 discoligamentous injuries. About 92.9% (13/14) of the patients had typical or atypical hangman's fracture; 100% (10/10) of the posterior TD fracture patients had hangman's fracture, but 75% (3/4) of the anterior TD fracture had hangman's fracture. At admission, 13 patients were neurologically intact. However, the remaining patient had spinal cord injury with American Spinal Injury Association (ASIA) impairment scale B with C_2‐3 bilateral facet dislocation. All four anterior TD fracture patients underwent posterior C_2‐3 fusion. While four of 10 posterior TD fracture patients underwent C_2‐3 anterior fusion, the remaining six underwent posterior fusion. At last follow‐up, 100% (14/14) of the patients achieved solid fusion, and visual analog scale for neck pain was significantly improved (5.9 vs 2.2, P < 0.001). One patient with ASIA impairment scale B had significantly improved to scale D. No major complications occurred.

Conclusion

Our study showed that surgically managed TD fractures of the C₂ showed a high incidence of other associated spine injuries including hangman's fracture and C_2‐3 discoligamentous injury. Therefore, special attention and careful radiologic evaluation are needed to investigate the presence of other associated spine injuries including hangman's fracture and C_2‐3 discoligamentous injury, which are likely to require surgery.

Proposal of Treatment Strategy for Pedicle Fractures of the C2: An Analysis of 49 Cases

Spine surgeons often confuse C2 pedicle fractures (PFs) with pars interarticularis fractures. In addition, little information is available about the characteristics and treatment strategies for C2 PFs. We sought to investigate the characteristics of C2 PFs and to propose an appropriate treatment strategy. A total of forty-nine patients with C2 PFs were included in this study. We divided these patients into unilateral and bilateral C2 PF groups. The incidence rates and characteristics of other associated C2 and C2-3 injuries, and other cervical injuries, were evaluated. In addition, treatment methods and outcomes were analyzed. Twenty-two patients had unilateral C2 PFs and twenty-seven patients had bilateral C2 PFs. Among the cases of unilateral C2 PFs, all patients had one or more other C2 fractures, and twenty patients (90.9%) had one or two C2 body fractures. Meanwhile, among the cases of bilateral C2 PF, all patients had two or more other C2 fractures and one or two C2 body fractures. In unilateral C2 PFs, three patients with C2-3 anterior slip or adjacent cervical spine (C1-3) injury underwent surgery and nineteen patients (86.4%) were treated with conservative methods. In bilateral C2 PFs, three patients with C2-3 anterior slip or SCI at C2-3 underwent surgery and twenty-four patients (88.9%) were treated with conservative methods. Our results showed that C2 PFs do not occur alone and are always accompanied by other associated C2 injuries. C2 PFs should, generally, be thought of as a more complex fracture type than hangman's fracture or dens fracture. Despite the complex fracture characteristics, most C2 PFs can be managed with conservative treatment. However, surgical treatments should be considered if the C2 PFs are accompanied by the C2-3 anterior slip and adjacent cervical spine injury.

Proposal of New Radiological Classification and Treatment Strategy for Transverse Fractures of the C2 Axis Body

OBJECTIVE

To investigate the characteristics of transverse fractures of the C2 axis body diagnosed on sagittal computed tomography (CT) and to propose new classification and appropriate treatment strategies.

METHODS

A retrospective study was performed by enrolling 49 patients (26 men and 23 women) with transverse fractures of the C2 axis body who were treated at four national trauma centers of tertiary university hospitals from January 2000 to December 2017. The mean age of the patients was 60.8 years (ranging from 21 to 90 years). We classified 49 transverse fractures of the C2 body into three types based on fracture trajectories involving superior articular facet (SAF) and lateral cortex (LC) of the C2 body on coronal CT as follows: Type 1, involvement of C2 SAF on both sides; Type 2, unilateral involvement of C2 SAF on one side and LC on the other side; Type 3, involvement of LC on both sides. The characteristics, treatment methods, and results of 49 transverse fractures of the C2 body were analyzed. Mean follow-up was 12.6 months (ranging from 12 to 26 months).

RESULTS

Twenty-six (53.1%) patients were Type 1, 21 (42.9%) were Type 2, and 2 (4.0%) were Type 3. Correlation coefficients for intra-observer and inter-observer reliabilities of classification were 0.723 and 0.598 (both, P < 0.001), respectively. About 40.8% (7 Type 1 and 13 Type 2) of the patients had fracture displacement >3 mm; Incidence of fracture displacement >3 mm was higher in Type 2 than Type 1 (61.9% vs 26.9%, P < 0.05). About 79.6% (20 Type 1, 17 Type 2 and 2 Type 3) of the patients were treated conservatively, and 20.4% (6 Type 1 and 4 Type 2) underwent surgery. At last follow-up, 47 out of 49 patients achieved fusion; overall fusion rate was 95.9%. All conservatively treated Type 1 and Type 3 patients achieved fusion. Out of 17 conservatively treated Type 2 patients, 15 achieved fusion but two developed nonunion; however, two nonunion patients opted not to undergo surgery. Subgroup analysis showed that Philadelphia brace caused nonunion significantly in fracture displacement >3 mm compared to Minerva brace/Halovest (100% vs 0%, P < 0.05). All surgically treated Type 1 and 2 patients achieved fusion. In terms of clinical outcomes, neck pain visual analog scale and neck disability index were significantly improved (both, P < 0.01). According to Odom's criteria, 93.9% (46/49) of the patients achieved satisfactory outcomes. No major complications occurred.

CONCLUSIONS

The majority of transverse fractures of C2 body can be treated conservatively. However, surgery or rigid Minerva brace/Halovest should be considered for Type 2 transverse fractures of the C2 body with fracture displacement >3 mm.

Anterior C2-3 fusion surgery alone for highly displaced Hangman's fracture with severe angulation of C2-3 of more than 30°

BACKGROUND

Highly displaced Hangman's fracture is a very rare and extremely unstable fracture of the C2 axis. Combined anteroposterior or posterior long-segment fusion surgery is typically performed for the treatment of highly displaced Hangman's fracture. However, these kinds of surgeries increase the risk of complications, loss of motion, and hospital costs.

OBJECTIVE

We sought to investigate the surgical outcomes of anterior C2-3 fusion surgery alone for highly displaced Hangman's fractures with severe angulation of C2-3 by more than 30° and discoligamentous injury.

METHODS

A total of five patients (four men and one woman) were included in this study with a mean age of 40.4 years (range, 26-70 years). The mean follow-up period after surgery was 37.2 months (range, 12-96 months). The fracture characteristics, treatment methods, and outcomes were retrospectively analyzed.

RESULTS

All five patients had type II Hangman's fractures (according to the Levine and Edwards classification scheme). None of the included patients had neurologic deficit or other spine injury but all patients had complete C2-3 discoligamentous injury. Before surgery, all patients successfully achieved closed reduction by skull traction, followed by C2-3 anterior decompression and fusion (ACDF) with plating. For interbody grafting, three patients received a polyetheretherketone (PEEK) cage filled with an autogenous cancellous iliac bone graft and two received autogenous tricortical iliac bone grafts. Severe angulation (39.2° vs. 3.0°, P < 0.001) and severe displacement (76.1% vs. 4.0%, P < 0.001) of C2-3 were both significantly corrected after surgery. All patients had achieved solid fusion at last follow-up. In terms of clinical outcomes, the mean neck pain visual analog scale score was significantly improved (8.6 points vs. 1.8 points, P < 0.001). The mean neck disability index value was also significantly improved (45.4 points vs. 13.0 points, P < 0.01). According to Odom's criteria, all patients achieved satisfactory outcomes. No major complications occurred. One patient complained of dysphagia, but recovered after three months with conservative treatment.

CONCLUSIONS

Preoperative closed reduction and anterior C2-3 fusion surgery alone should be considered as a less-invasive and useful surgical option for highly displaced Hangman's fracture with severe angulation of C2-3, which is an extremely unstable fracture of the C2 axis.

Analysis of Nonunion in Conservatively Managed Anterior Tear Drop Fractures of C2 Vertebra

Many anterior C2 (2nd cervical vertebra) tear drop (TD) fractures can be successfully managed with conservative treatment. However, due to the occurrence of nonunion, large-sized or complex anterior C2 TD fractures undergo surgical treatment. To date, no surgical treatment guidelines are available about anterior C2 TD fractures. Therefore, we performed this study to investigate the factors that may affect nonunion for anterior C2 TD fractures and to suggest surgical treatment guidelines. Thirty-three patients with anterior C2 TD fractures, who underwent conservative treatment and had a minimum 1-year follow-up, were divided into union (N = 26) and nonunion (N = 7) groups. Their radiological and clinical data were analyzed retrospectively and compared between the two groups. The avulsion fracture ratio (29.5% vs. 43.3%, p < 0.05) and fracture displacement (3.6 mm vs. 5.1 mm, p < 0.05) were higher in the nonunion group compared to the union group. Incidence of associated C2 injury was higher in the nonunion group compared to the union group (15.4% vs. 57.1%, p < 0.05). Union status was negatively correlated with associated C2 injury (correlation coefficient, CC = -0.398, p < 0.05). Our results suggest that surgical treatment could be considered for anterior C2 TD fractures with an avulsion fracture ratio > 43%, fracture displacement > 5 mm, or associated C2 injury.

The use of Grauer classification in the management of type II odontoid fracture in elderly: Prognostic factors and outcome analysis in a single centre patient series

OBJECTIVE

To evaluate the results of Type II odontoid fractures management in the elderly, according to the Grauer classification.

METHODS

Consecutive patients with type II odontoid fracture, age > 65 years and follow-up longer than 3 months were included. Fracture management was proposed according to Grauer classification. Peri-surgical risk factors, NDI, VAS and rate of fusion were evaluated according to the treatment modality and compared between conservative and surgical groups.

RESULTS

Thirty-four patients were considered eligible for the study; 2 patients showed a Type IIa fracture, 30 patients a type IIb, and 2 patients a type IIc. Type IIa patients underwent conservative treatment that resulted in failure. A conservative management was adopted in 9 cases with type IIb due to patient preference or anaesthesiologic reasons with a treatment success at 6 months of 11%. Trans-odontoid stabilization was adopted in 21 type IIb cases with an evidence of bony or fibrous union at 6 months of 95% and a median NDI of 20%. A posterior approach was reserved for 2 type IIc fracture patients and in 6 cases as rescue surgery (bony union at 6 months of 100%; median NDI 37%). Higher Lakshmanan grade, gap and displacement of the fracture were found as significant risk factor for fracture non-union (p < 0.05).

CONCLUSIONS

The surgical group presented better clinical and radiological outcome and the anterior approach proved to achieve the best results in type IIb fractures. The presence of osteoporosis and fracture spatial features should be duly considered in the decision-making process.

Spine Trauma

Spine trauma is a common indication for diagnostic imaging, and there has been a gradual shift to using cross-sectional imaging techniques for screening and evaluating the injured spine, particularly in elderly patients where radiography can be challenging. The classification of spinal injuries has evolved in the past decades to rely on a combination of fracture morphology as defined by diagnostic imaging in conjunction with the clinical presentation to stratify patients to determine optimal management. Radiologists need to be familiar with these classification systems, which rely heavily on imaging findings using CT and MRI, to accurately describe spinal injury.

Management and long-term outcome of type II acute odontoid fractures: a population-based consecutive series of 282 patients

BACKGROUND CONTEXT

The surgical fixation rate of type II odontoid fracture (OFx) in the elderly (≥65 years) is much lower than expected if the treatment adheres to current general treatment recommendations. Outcome data after conservative treatment for elderly patients with these fractures are sparse.

PURPOSE

The main aim of this study was to determine the long-term outcome after conservative and surgical treatments of type II OFx (all age-groups) to evaluate whether nonoperative treatment yields an acceptable outcome.

STUDY DESIGN/SETTING

Retrospective study based on a prospective database.

PATIENT SAMPLE

Two hundred eighty-two consecutive patients with type II OFx treated at Oslo University Hospital over an 8-year period.

OUTCOME MEASURES

Long-term rates of bony fusion, fibrous union, pseudarthrosis, crossover from primary conservative treatment to surgical fixation, new-onset spinal cord injury (SCI), and neck pain were the outcome measures used.

METHODS

The present study was based on data extracted from our quality control database for acute cervical spine fractures. All ages were included. In addition, long-term follow-up of alive patients was performed during the years 2018-2019. The follow-up included neurological examination, radiological examination, and scoring of bony fusion status, crossover from primary conservative treatment to surgical fixation, new-onset SCI, neck pain, and Neck Disability Index (NDI score). Data are described by counts, percentages, medians, means, ranges and standard deviations where appropriate. For statistical analyses the Mann-Whitney U test, Wilcoxon signed-rank test, and t tests were used.

RESULTS

During the eight-year study period, we registered 282 consecutive patients with type II OFx; 54% were males, patient age ranged from 15 to 101 years, 84% were ≥65 years of age (WHO definition of elderly), and 51% were ≥80 years of age. Severe comorbidities (American Society of Anesthesiologists, ASA ≥3) were seen in 67%, whereas nonindependent living was registered in 32%. Severe comorbidities and nonindependent living were significantly associated with increasing age (p<.001). SCI secondary to the OFx was seen in 5.3%. Primary treatment of the OFx was conservative (external immobilization alone) in 193 patients (68.4%), open surgical fixation in 87 patients (30.9%), and no treatment in two critically injured patients. At the time of long-term follow-up, 125 patients had died, nine patients declined the invitation to follow-up, and five patients did not respond. Thus, 143 patients were available for follow-up with a median follow-up time of 39 months (range 5-115 months). At long-term follow-up, the fusion status was bony fusion in 39.2% of patients, fibrous union in 57.3%, and pseudarthrosis in 3.5%. The proportion of bony fusion was significantly higher in the primary surgical fixation group (p=.005). No patients had new-onset SCI presenting after the start of primary treatment. The proportion of crossover from primary external immobilization to surgery was 14.4%, whereas proportion of revision surgery in the primary surgical group was 9.5%. There was no significant difference between the primary surgical fixation group and the primary conservative treatment group at long-term follow-up with respect to the proportion of pseudarthrosis and degree of neck pain.

CONCLUSIONS

Primary conservative treatment of elderly patients with type II OFx appears to be safe and should be regarded a viable treatment option.

Odontoid fractures: impact of age and comorbidities on surgical decision making

Background

Surgical fixation is recommended for type II and III odontoid fractures (OFx) with major translation of the odontoid fragment, regardless of the patient’s age, and for all type II OFx in patients aged ≥50 years. The level of compliance with this recommendation is unknown, and our hypothesis is that open surgical fixation is less frequently performed than recommended. We suspect that this discrepancy might be due to the older age and comorbidities among patients with OFx.

Methods

We present a prospective observational cohort study of all patients in the southeastern Norwegian population (3.0 million) diagnosed with a traumatic OFx in the period from 2015 to 2018.

Results

Three hundred thirty-six patients with an OFx were diagnosed, resulting in an overall incidence of 2.8/100000 persons/year. The median age of the patients was 80 years, and 45% were females. According to the Anderson and D’Alonzo classification, the OFx were type II in 199 patients (59%) and type III in 137 patients (41%). The primary fracture treatment was rigid collar alone in 79% of patients and open surgical fixation in 21%. In the multivariate analysis, the following parameters were significantly associated with surgery as the primary treatment: independent living, less serious comorbidities prior to the injury, type II OFx and major sagittal translation of the odontoid fragment. Conversion from external immobilization alone to subsequent open surgical fixation was performed in 10% of patients. Significant differences the in conversion rate were not observed between patients with type II and III fractures. The level of compliance with the treatment recommendations for OFx was low. The main deviation was the underuse of primary surgical fixation for type II OFx. The most common reasons listed for choosing primary external immobilization instead of primary surgical fixation were an older age and comorbidities.

Conclusion

Major comorbidities and an older age appear to be significant factors contributing to physicians’ decision to refrain from the surgical fixation of OFx. Hence, comorbidities and age should be considered for inclusion in the decision tree for the choice of treatment for OFx in future guidelines.

Comparative Propensity-Weighted Mortality After Isolated Acute Traumatic Axis Fractures in Older Adults

INTRODUCTION

In older patients with axis fractures, the survival benefit from surgery is unclear due to high baseline mortality. Comparative effectiveness research can provide evidence from population level cohorts. Propensity weighting is the preferred methodology for reducing bias when analyzing national administrative cohort data for these purposes but has not yet been utilized for this important surgical conundrum. We estimate the effect of surgery on mortality after isolated acute traumatic axis fracture in older adults.

MATERIALS AND METHODS

We used a retrospective population-based cohort of Medicare patients and generated a propensity score-weighted nonsurgical cohort and compared mortality with and without surgery. This balanced the comorbid conditions of the treatment groups. Incident fractures were defined using a predetermined algorithm based on enrollment, code timing, and billing location. The primary outcome was adjusted all-cause 1-year mortality.

RESULTS

From 12 372 beneficiaries with 1-year continuous enrollment and a coded axis fracture, 2676 patients met final inclusion/exclusion criteria. Estimated incidence was 16.5 per 100 000 person-years overall in 2014 (95% confidence interval [CI]: 15.0-18.0) and was stable from 2008 through 2014. Patients with axis fracture had a mean age of 82.8 years, 30.2% were male, and 91.9% were Caucasian. Mortality was 3.8 times higher (CI 3.6-4.1) compared with the general population of older US adults. Propensity-weighted mortality at 1 year for nonsurgical patients was 26.7 of 100 (CI: 24.5-29.0). Mortality for surgical patients was significantly lower (19.7/100; CI 14.5-25.0). Risk difference was 7.0 fewer surgical deaths per 100 patients (CI: 1.3-12.7). Surgical patients aged 65 to 74 years had the largest difference in mortality with 11.2 fewer deaths per 100 (CI: 1.1-21.3).

DISCUSSION

Patients with axis fractures are predominantly older Caucasian women and have a higher mortality rate than the general population. Propensity-weighted mortality at 1-year was lower in the surgical patients with the largest risk difference occurring in patients 65 to 74 years old.

CONCLUSIONS

Surgery may provide an independent survival benefit in patients aged 65 to 75 years, and the mortality difference diminishes thereafter.

Novel In Situ Open Reduction and Fixation of a Displaced Type II Odontoid Fracture

BACKGROUND

Surgical intervention for type II odontoid fractures is a common treatment strategy when conservative management is not appropriate, such as in significantly displaced fractures. However, displaced fractures may not be easily reduced with instrumentation alone. We present a novel technique, using a "bucket-handle" construct to manually reduce a dorsally displaced type II odontoid fracture, in a patient with failure of previously placed dorsal instrumentation.

METHODS

A 63-year-old woman underwent posterior sublaminar wiring and fixation of a type II odontoid fracture at an outside institution. Several weeks later, she presented with graft dislodgement and increased dorsal displacement and angulation of her fractured dens. After removal of her prior instrumentation and placement of segmental instrumentation, a novel construct was created using components from the instrumentation system and was attached to her cervical 2 (C2) screws.

RESULTS

Dorsal traction on the C2 pars interarticularis screws allowed for manual reduction of her fracture via a 3-point bending moment. This reduction was secured with an occiput to C6 fixation and fusion. She is clinically and radiographically stable at 3-months follow-up.

CONCLUSIONS

This novel "bucket-handle" construct, used in conjunction with occipitocervical fusion, allowed safe and durable manual reduction of a dorsally displaced and angulated type II odontoid fracture.

Characteristics and Management of Emergency Department Patients Presenting with C2 Cervical Spine Fractures

Background

C2 cervical fractures account for approximately 18% of cervical spine injuries. Few studies have examined patients presenting to an emergency department (ED) with this injury relative to demographics, injury mechanism, and hospital course.

Objectives

To compare multiple variables of ED patients presenting with these types of injuries.

Methods

In this retrospective cohort study, data were obtained from the Trauma Registry of an academic trauma referral center from January 1, 2011, to December 31, 2015. Patients who presented with a C2 fracture were identified. Information regarding the patient's gender, age, mechanism of injury, associated injuries, if a procedure was required, disposition, and mortality was extracted. Comparative analyses were conducted between cases over or under age 60.

Results

Between January 1, 2011, to December 31, 2015, a total of 139 patients with C2 fractures were identified. Most patients were 60 years or older (79%). Of those, 62% were female, and falls were the most common mechanism (78%). Of those under 60, 50% were female and motor vehicle crashes (MVCs) were the most common mechanism (71%). Odontoid fractures comprised 84% of C2 fractures. Only 6% had an associated spinal cord injury. Less than one-third of patients required operative intervention for their spinal injuries, and intervention was more common in older patients. Following admission, 19% of patients required placement into a nursing home or skilled nursing facility.

Conclusions

C2 fractures are more common in older adults and usually resulted from falls. Odontoid fractures are most common. Most C2 fractures do not result in neurologic injury, and only a third were treated surgically. However, several patients were unable to return to their homes following their injury.

Min-invasive surgical treatment for multiple axis fractures: A case report

BACKGROUND

Fractures of the axis are commonly seen in spinal injuries. Upper cervical fractures are usually managed conservatively. However, the complications due to long-term external immobilization cannot be ignored. The traditional open surgery has the disadvantages of too much blood loss and soft tissue injury. The aim of our paper is to introduce a minimally invasive surgical treatment for multiple axis fractures.

CASE SUMMARY

We report a 40-year-old Chinese male who had severe neck pain and difficult neck movement after falling from 3 meters. X-ray and computed tomography (CT) scan revealed an axis injury consisting of an odontoid Type III fracture associated with a Hangman fracture categorized as a Levine-Edwards Type I fracture. The patient underwent anterior odontoid screw fixation and posterior percutaneous screw fixation using intraoperative O-arm navigation. Neck pain was markedly improved after surgery. X-rays and CT scan reconstructions of 3-mo follow-up showed good stability and fusion. The range of cervical motion was well preserved.

CONCLUSION

Anterior odontoid screw fixation and posterior direct C2 percutaneous pedicle screw fixation with the aid of O-arm navigation and neurophysiological monitoring can be an interesting alternative option for complicated multiple axis fractures.

The Decision-Making Process in Traumatic Lesions of the Craniovertebral Junction: An Evidence-Based Approach? Part II

This paper is Part II of a two-part report. Part I of the report covered atlanto-occipital dislocation or dissociation, and isolated condylar fractures. This part of the report covers isolated and combination fractures of the atlas and axis.

Management of Combined Atlas Fracture with Type II Odontoid Fracture: A Review of 21 Cases

PURPOSE

To evaluate the therapeutic effects of combined atlas fracture with type II (C₁-type II) odontoid fractures and to outline a management strategy for it.

PATIENTS AND METHODS

Twenty three patients with C₁-type II odontoid fractures were treated according to our management strategy. Nonoperative external immobilization in the form of cervical collar and halo vest was used in 13 patients with stable atlantoaxial joint. Surgical treatment was early performed in 10 patients whose fractures with traumatic transverse atlantal ligament disruption or atlantoaxial instability. The visual analog scale (VAS), neck disability index (NDI) scale, and American Spinal Injury Association (ASIA) scale at each stage of followup were then collected and compared.

RESULTS

Compared to pretreatment, the VAS score, NDI score, and ASIA scale were improved among both groups at followup evaluation after treatment. However, in the nonsurgical group, one patient (1/11) developed nonunion which required surgical treatment in later stage and one patient (1/13) with halo vest immobilization had happened pin site infection. Two patients of the surgical group (2/11) had appeared minor complications: occipital cervical pain in one case and cerebrospinal fluid leakage in one case. Two patients (2/23) were excluded from nonsurgical treatment group because their followup period was less than 12 months. Twenty one patients were followed up regularly with an average of 23.9 months (range 15-45 months).

CONCLUSIONS

We outlined our concluding management principle for the treatment of C₁-type II odontoid fractures based on the nature of C₁ fracture and atlantoaxial stability. The treatment principle can obtain satisfactory results for the management of C₁-type II odontoid fractures.

Biomechanics and common mechanisms of injury of the cervical spine

The cervical spine functions to position the head while maintaining stability and protecting the spinal cord. The anatomy of the cervical spine dictates the amount of physiologic motion at each level. Knowledge of the normal biomechanical anatomy of the cervical spine is imperative to the understanding of the biomechanics of injury to the cervical spine. There are a variety of reproducible injury patterns based on the direction and magnitude of force applied to the cervical spine. Knowledge of these forces can allow an understanding of the mechanical and neurologic stability of the cervical spine and can also help guide treatment options. It is also important to understand the mechanism of injury and injured cervical structures based on radiographic findings, as often patients will present with neurologic examinations that also reflect noncervical spine-related injuries. The goal of this chapter is to present a review of the normal biomechanics of the cervical spine, in addition to presenting different injury patterns of the cervical spine from the minor to life-threatening, with the goal of maximizing postinjury function by ensuring proper treatment protocols are followed.

Minimally Invasive Unilateral Percutaneous Transfracture Fixation of a Hangman's Fracture Using Neuronavigation and Intraoperative Fluoroscopy

BACKGROUND

Traumatic spondylolisthesis or hangman's fracture is a common cervical spine fracture. Most cases of traumatic spondylolisthesis are treated nonoperatively with external immobilization. The indications for surgery have generally included fracture instability or failed nonoperative management. Operative stabilization can be performed through either anterior or posterior approaches and has generally required instrumentation using open methods. We propose a technique for surgical repair of hangman's fracture that is minimally invasive and motion preserving using recent advances in 3-dimensional image-guidance technology. We believe this method represents another option in the treatment of hangman's fractures, because it allows for immediate stabilization, prompt recovery, and quick mobilization.

CASE DESCRIPTION

We present the case of 2 patients with hangman's fractures who had undergone surgical unilateral transfixation with minimally invasive percutaneous screw placement. In both cases, we used 3-dimensional neuronavigation and bidirectional intraoperative fluoroscopy. The operative time from incision to closure was <30 minutes. Preparation and positioning after intubation varied from 40 to 150 minutes. No intraoperative complications occurred. Both patients were discharged within 48 hours postoperatively. The follow-up examinations at 3 months, 12 months, and 5 years revealed healthy bony fusion on computed tomography imaging and an excellent clinical recovery.

CONCLUSION

We have provided 2 examples in which minimally invasive unilateral fixation of hangman's fractures proved to be safe and effective. In both cases, the patients were immediately relieved of their pain, quickly mobilized, and promptly discharged. The achievement of successful fusion confirmed at the follow-up examinations.

Treatment of Axis Body Fractures: A Systematic Review

STUDY DESIGN

Evidence-based systematic review.

OBJECTIVES

To define the optimal treatment of fractures involving the C2 body, including those with concomitant injuries, based upon a systematic review of the literature.

SUMMARY OF BACKGROUND DATA

Axis body fractures have customarily been treated nonoperatively, but there are some injuries that may require operative intervention. High-quality literature is sparse and there are few class I or class II studies to guide treatment decisions.

MATERIALS AND METHODS

A literature search was conducted using PubMed (MEDLINE), Cochrane Central Register of Controlled Trials, and Scopus (EMBASE, MEDLINE, COMPENDEX). The quality of literature was rated according to a grading tool developed by the Center for Evidence-based Medicine. Operative and nonoperative treatment of axis body fractures were compared using fracture bony union as the primary outcome measure. As risk factors for nonunion were not consistently reported, cases were analyzed individually.

RESULTS

The literature search identified 62 studies, of which 10 were case reports which were excluded from the analysis. A total of 920 patients from 52 studies were included. The overall bony union rate for all axis body fractures was 91%. Although the majority of fractures were treated nonoperatively, there has been an increasing trend toward operative intervention for Benzel type III (transverse) axis body fractures. Nearly 76% of axis body fractures were classified as type III fractures, of which 88% united successfully. Nearly all Benzel type I and type II axis body fractures were successfully treated nonoperatively. The risk factors for nonunion included: a higher degree of subluxation, fracture displacement, comminution, concurrent injuries, delay in treatment, and older age.

CONCLUSIONS

High rates for fracture union are reported in the literature for axis body fractures with nonoperative treatment. High-quality prospective studies are required to develop consensus as to which C2 body fractures require operative fixation.

Management of Odontoid Fractures in the Elderly: A Review of the Literature and an Evidence-Based Treatment Algorithm

Odontoid fractures are the most common fracture of the axis and the most common cervical spine fracture in patients over 65. Despite their frequency, there is considerable ambiguity regarding optimal management strategies for these fractures in the elderly. Poor bone health and medical comorbidities contribute to increased surgical risk in this population; however, nonoperative management is associated with a risk of nonunion or fibrous union. We provide a review of the existing literature and discuss the classification and evaluation of odontoid fractures. The merits of operative vs nonoperative management, fibrous union, and the choice of operative approach in elderly patients are discussed. A treatment algorithm is presented based on the available literature. We believe that type I and type III odontoid fractures can be managed in a collar in most cases. Type II fractures with any additonal risk factors for nonunion (displacement, comminution, etc) should be considered for surgical management. However, the risks of surgery in an elderly population must be carefully considered on a case-by-case basis. In a frail elderly patient, a fibrous nonunion with close follow-up is an acceptable outcome. If operative management is chosen, a posterior approach is should be chosen when fracture- or patient-related factors make an anterior approach challenging. The high levels of morbidity and mortality associated with odontoid fractures should encourage all providers to pursue medical co-management and optimization of bone health following diagnosis.

Posterior Bilateral Intermuscular Approach for Upper Cervical Spine Injuries

OBJECTIVE

To investigate a novel intermuscular surgical approach for posterior upper cervical spine fixation.

METHODS

Twenty-three healthy volunteers underwent magnetic resonance imaging. By using the magnetic resonance imaging scans in transverse view at the level of lower edge of atlas, the distances from the posterior midline to lateral margin of trapezius, to the medial margin of splenius capitis, and to middle line of semispinalis capitis were recorded. The angle between posterior middle line and the line crossing the lateral margin of trapezius and middle point of ipsilateral pedicles. From October 2009 to May 2013, 12 patients with upper cervical spine injuries were operated via the bilateral intermuscular approach. The time required for surgery, blood loss, and pre- and postoperative visual analogue scale scores were analyzed.

RESULTS

The average distance of 0-T was 39.2 ± 7.5 mm, the angle between the approach and posterior middle line was 33.2 ± 8.4°. The surgical time was 78.3 ± 22.5 minutes (45-140 minutes), and the mean intraoperative blood loss was 87.5 ± 44.2 mL (30-200 mL). Preoperative and postoperative visual analogue scale scores were 6.4 ± 0.8 and 1.8 ± 0.7, respectively. The average follow-up time was 19.7 ± 11.5 months (9-48 months).

CONCLUSIONS

The posterior bilateral intermuscular approach for upper cervical spine injuries is a valid alternative for Hangmans' fractures type I, type II, and type Ia according to Levine and Edwards classification as well as atlantoaxial subluxation caused by upper cervical spine trauma.

True oblique axis fracture associated with congenital anomalies of the upper cervical spine: Case report of an unusual fracture pattern

Background:

Acute traumatic axis fractures are common cervical spine injuries often caused by road accidents or falls. They are usually classified into three different types, namely, odontoid fractures, Hangman's fractures, and miscellaneous fractures. Congenital malformations of the craniovertebral junction (CVJ), although typically asymptomatic, may result in neural compression or instability, especially following trauma. Here, the authors present an unusual oblique axis fracture occurring in conjunction with several malformations of the upper cervical spine.

Case Description:

Following a motor vehicle accident, a 25-year-old female's radiographic studies showed an oblique axis fracture involving both the anterior and posterior elements along with an anterior and posterior Klippel–Feil syndrome (KFS) anomaly. Following treatment in a halo vest, the patient maintained alignment, and ultimately the fracture was fused.

Conclusions:

True oblique fractures of the axis are rare, as in the case presented, and may occasionally occur in conjunction with KFS of the upper cervical spine.

The craniocervical junction: embryology, anatomy, biomechanics and imaging in blunt trauma

Imaging of the blunt traumatic injuries to the craniocervical junction can be challenging but central to improving morbidity and mortality related to such injury. The radiologist has a significant part to play in the appropriate management of patients who have suffered injury to this vital junction between the cranium and the spine. Knowledge of the embryology and normal anatomy as well as normal variant appearances avoids inappropriate investigations in these trauma patients. Osseous injury can be subtle while representing important radiological red flags for significant underlying ligamentous injury. An understanding of bony and ligamentous injury patterns can also give some idea of the biomechanics and degree of force required to inflict such trauma. This will assist greatly in predicting risk for other critical injuries related to vital neighbouring structures such as vasculature, brain stem, cranial nerves and spinal cord. The embryology and anatomy of the craniocervical junction will be outlined in this review and the relevant osseous and ligamentous injuries which can arise as a result of blunt trauma to this site described together. Appropriate secondary radiological imaging considerations related to potential complications of such trauma will also be discussed.

TEACHING POINTS

• The craniocervical junction is a distinct osseo-ligamentous entity with specific functional demands. • Understanding the embryology of the craniocervical junction may prevent erroneous radiological interpretation. • In blunt trauma, the anatomical biomechanical demands of the ligaments warrant consideration. • Dedicated MRI sequences can provide accurate evaluation of ligamentous integrity and injury. • Injury of the craniocervical junction carries risk of blunt traumatic cerebrovascular injury.

Direct C2 Pedicle Screw Fixation for Axis Body Fracture

BACKGROUND

Acute complex C2 vertebral body fracture specifically does not involve the odontoid process or C2 pars interarticularis. External stabilization can be effective but may prolong healing and increase morbidity. Many traditional surgical techniques can achieve internal stabilization at the expense of normal cervical motion. We describe direct surgical C2 pedicle screw fixation as an option for managing acute complex C2 vertebral body fracture.

CASE DESCRIPTION

Three patients were treated with direct pedicle screw fixation of acute traumatic complex C2 vertebral body fractures. All fractures were coronally oriented Benzel type 1. None of the patients sustained neurological injury. Stereotactic navigation with intraoperative computed tomography scanning was used for each procedure. Surgery provided immediate internal orthosis and stability, as judged by intraoperative dynamic fluoroscopy. Rigid cervical collar bracing was used for 1 month after surgery when the patients were out of bed. Initial radiographs showed acceptable screw placement and fracture alignment. Dynamic radiographs at 3 months showed structural stability at the fracture site and adjacent levels, and complete bony union was confirmed with late computed tomography scanning (>1 year) in each case. Each patient reported resolution of trauma-related and postsurgical pain at 30-day follow-up. Postoperative Neck Disability Index questionnaires for each patient suggested no significant disability at 1 year.

CONCLUSIONS

Direct pedicle screw fixation of acute complex C2 vertebral body fracture appeared to be safe and effective in our 3 patients. It may provide a more-efficient and less-morbid treatment than halo brace or cervical collar immobilization in some patients.

Anterior Reduction, Discectomy, and Three Cortical Iliac Bone Grafting With Instrumentation to Treat A Huge Tear Drop Fracture of the Axis: A Case Report and Literature Review

Fractures of the axis body have been little reported and treatment strategies remain controversial and individualized. Not more than 10 cases of huge tear drop fracture of the axis (HTDFA) have been reported in previous studies and the treatment method varies from conservative treatment to an anterior, or posterior, approach surgery. Considering the sparse knowledge of HTDFA, we present a special case report to share our experience and to explore the safety and effectiveness of anterior reduction and fusion to treat HTDFA. A 24-year-old man was referred to our department; he presented with neck pain lasting for 12 h since being involved in a roll-over motor vehicle accident. His neck movement was limited but there was no neurological compromise. Physical examination of the patient showed myodynamia of four limbs Grade 5, Hoffmann sign (-), and Babinski sign (-). Three-dimensional reconstruction computed tomography (CT) confirmed a huge tear drop fracture of the anterior-inferior corner of the axis and discontinuity of the cortex of the axis. After discussion with the spinal surgeon team in the department and an effective conversation with the patient, surgery involving anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation after transnasal induction of general anesthesia was performed. The patient was instructed to wear a cervical collar until he returned to our department for a follow-up examination some 3 months after surgery. The 3-month postoperative x-ray and CT scan showed a good position of the implant and bony fusion at the C2/3 segment. Anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation to treat HTDFA are effective, safe, and simple. Of course, longer follow-up duration and more cases are warranted to verify this procedure. Anterior reduction, discectomy, and bone grafting with instrumentation are warranted for most HTDFA cases. However, if HTDFA incorporates other complex fractures, such as fracture of the posterior structure, an anterior and posterior union surgery is recommended.

Hydrocephalus Caused by Fat Embolism: A Rare Complication of Atlanto-Axial Fixation for Odontoid Fractures

BACKGROUND AND IMPORTANCE

Odontoid fracture is not uncommon and surgical treatment that uses posterior screw/rod fixation is an acceptable option. This is the first report of delayed hydrocephalus due to subarachnoid fat migration as a complication of posterior atlanto-axial (AA) fixation.

CASE DESCRIPTION

A 27-year-old man underwent posterior C1 lateral mass and C2 pedicle screw fixation for a recent Anderson-D'Alonzo type 2 odontoid fracture. Autologous bone graft was wired for onlay fusion. The surgery was smooth, except that there was an incidental durotomy intraoperatively. The patient had significant relief of his neck pain, although computed tomography (CT) demonstrated a medial breach of the left C1 screw postoperation; however, he gradually developed headache and dizziness after discharge. Five weeks after operation, magnetic resonance imaging demonstrated a large pseudo-meningocele at the surgical site, which was managed conservatively. Nine weeks after the AA fixation, the patient was sent to the emergency department for altered consciousness. A brain CT demonstrated hydrocephalus and multiple fat emboli in the subarachnoid and intraventricular space. A ventriculoperitoneal shunt was inserted to manage the hydrocephalus and pseudo-meningocele. The patient recovered well and was followed up to 13 months after operation. To date, this was the first report of delayed hydrocephalus caused by fat embolism after AA fixation surgery.

CONCLUSIONS

Incidental durotomy in posterior AA fixation may predispose the patient to a serious complication of fat-cerebrospinal fluid embolism and subsequent hydrocephalus. There should be a heightened awareness for such a complication. Both CT and magnetic resonance imaging are useful for the diagnosis of subarachnoid fat droplets.

A Novel Anterior Odontoid Screw Plate for C1-C3 Internal Fixation: An In Vitro Biomechanical Study

STUDY DESIGN

A biomechanical in vitro study was performed using a standardized experimental protocol in a biomechanical spine testing apparatus.

OBJECTIVE

The aims of this study were to evaluate the biomechanical stability afforded by 4 cervical fixation techniques: anterior cervical plate+odontoid screw+cage (ACP+OS+cage), anterior odontoid screw plate+bone graft (AOSP+bone graft), posterior C2-3 fixation+odontoid screw (C2PS+C3LMS+OS), and posterior C1-3 fixation (C1PS+C2PS+C3LMS).

SUMMARY OF BACKGROUND DATA

Unstable axis injuries with multiple fracture lines are uncommon injuries, and their management is still challenging for surgeons who aim to achieve primary stability, early mobilization, preserved cervical range of motion (ROM), and favorable outcome. We designed a novel AOSP to assist in this challenging clinical scenario.

METHODS

Eight fresh-frozen cadaveric spine specimens (C1-C3) were subjected to stepwise destabilization of the C1-3 complex, with serial replication of a type II Hangman fracture, a type II odontoid fracture, and a C2 to C3 disc injury. Intact specimens, destabilized specimens, and destabilized specimens with various stabilization techniques including anterior and posterior techniques, some using our AOSP, were each tested for stability. Each spine was subjected to flexion, and extension testing, left and right lateral bending, and left and right rotation.

RESULTS

After AOSP+bone graft fixation, the ROMC2-C3 during all loading modes were reduced to values that were significantly less than normal. During all loading modes, AOSP+bone graft fixation significantly outperformed the ACP+OS+cage fixation in limiting ROMC2-C3. During flexion and extension, AOSP+bone graft fixation significantly outperformed the C1PS+C2PS+C3LMS fixation and C2PS+C3LMS+OS fixation in limiting ROMC2-C3.

CONCLUSION

The AOSP has excellent biomechanical performance when dealing with type I Hangman fractures, type II odontoid fractures, and C2-3 disc injuries. The AOSP+one graft fixation can preserve the function of atlanto-axial joint, which may be a valuable stabilization strategy for these unique injuries.

Cervical cage without plating in management of type II / II A Hangman's fracture combined with intervertebral disc injury

BACKGROUND

Surgical intervention is increasingly performed as the primary treatment of unstable Hangman's fracture. Some authors have advocated using anterior C2/3 discectomy with interbody fusion and plating to treat unstable Hangman's fracture combined with intervertebral disc injury; however, there are few reports on unstable Hangman's fracture treated by anterior interbody fusion with the cervical cage (PEEK material) solely.

METHODS

This study was to assess the efficacy of the cervical cage in management of unstable Hangman's fracture combined with intervertebral disc injury. A cohort of 15 patients with unstable Hangman's fractures fulfilling the inclusion criteria were prospectively submitted to surgical treatment of anterior C2/3 discectomy and interbody fusion using the cervical cage without plating. According to the Levine and Edwards classification, there were 5 type II, and 10 type IIA cases. The clinical outcome (the visual analog scale and the clinical post-traumatic neck score), radiological findings (angulation, translation, and disc height), and bone healing were assessed at 3, 6, 12, and 24 months.

RESULTS

All the patients were followed up successfully. There were no intra- or postoperative complications observed. Solid fusion was achieved in all cases by 6 months after surgery. The local kyphotic angle was corrected significantly with the mean preoperative 12.31 ± 2.96 degrees, initial postoperative -1.98 ± 1.62 degrees and the latest follow-up -1.72 ± 1.60 degrees respectively (P < 0.05).The translation was also corrected significantly with the mean preoperative 3.20 ± 1.16 mm, initial postoperative 0.97 ± 0.36 mm, and the latest follow-up 1.05 ± 0.34 mm respectively (P < 0.05). The mean visual analog scale and the clinical post-traumatic neck score improved significantly following surgery (P < 0.05).

CONCLUSIONS

This case series demonstrates that anterior C2/3 discectomy and interbody fusion with the cervical cage solely is effective and reliable in management of type II / IIA Hangman's fracture with C2/3 disc injury when properly indicated.

The Dens: Normal Development, Developmental Variants and Anomalies, and Traumatic Injuries

Accurate interpretation of cervical spine imagining can be challenging, especially in children and the elderly. The biomechanics of the developing pediatric spine and age-related degenerative changes predispose these patient populations to injuries centered at the craniocervical junction. In addition, congenital anomalies are common in this region, especially those associated with the axis/dens, due to its complexity in terms of development compared to other vertebral levels. The most common congenital variations of the dens include the os odontoideum and a persistent ossiculum terminale. At times, it is necessary to distinguish normal development, developmental variants, and developmental anomalies from traumatic injuries in the setting of acute traumatic injury. Key imaging features are useful to differentiate between traumatic fractures and normal or variant anatomy acutely; however, the radiologist must first have a basic understanding of the spectrum of normal developmental anatomy and its anatomic variations in order to make an accurate assessment. This review article attempts to provide the basic framework required for accurate interpretation of cervical spine imaging with a focus on the dens, specifically covering the normal development and ossification of the dens, common congenital variants and their various imaging appearances, fracture classifications, imaging appearances, and treatment options.

Odontoid process fractures: the role of the ligaments in maintaining stability. A biomechanical, cadaveric study

Aims: We wished to investigate the role of the cervical ligaments in maintaining atlantoaxial stability after fracture of the odontoid process.

Methods: We dissected eight fresh-frozen cadaveric cervical spines to prepare the C1 and C2 vertebrae for biomechanical analysis. The C1 and C2 blocks were mounted and biomechanical analysis was performed to test the stability of the C1-C2 complex after cutting the odontoid process to create an Anderson and D’Alonzo type II fracture then successive division of the atlantoaxial ligaments. Biomechanical analysis of stiffness, expressed as Young’s modulus, was performed under right rotation, left rotation and anterior displacement.

Results: The mean Young’s modulus in anterior displacement decreased by 37% when the odontoid process was fractured (p = 0.038, 95% confidence interval 0.04–1.07). The mean Young’s modulus in anterior displacement decreased proportionally (compared to the previous dissection) by the following percentages when the structures were divided: facet joint capsules (bilateral) 16%, ligamentum flavum 27%, anterior longitudinal ligament 10%. These differences did not reach statistical significance (p > 0.05).

Discussion: We have found that the odontoid process itself may account for up to 37% of the stiffness of the C1-C2 complex and that soft tissue structures account for further resistance to movement. We suggest magnetic resonance imaging (MRI) of the soft tissues in the acute setting of a minimally displaced odontoid process fracture to plan management of the injury. If the MRI determines that there is associated ligament injury it is likely that the fracture is unstable and we would suggest operative management.

Atlantoaxial instability in acute odontoid fractures is associated with nonunion and mortality

BACKGROUND CONTEXT

Odontoid fractures are the most common geriatric cervical spine fractures. Nonunion rates have been reported to be up to 40% and mortality up to 35%, and poor functional outcomes are common. Atlantoaxial instability (AAI) is a plausible prognostic factor, but its role has not been previously examined.

PURPOSE

To determine the effect of severe AAI on the outcomes of nonunion and mortality in patients with acute odontoid fractures.

STUDY DESIGN

Retrospective cohort/single institution.

PATIENT SAMPLE

One hundred twenty-four consecutive patients with acute odontoid fractures.

OUTCOME MEASURES

Rates of nonunion and mortality.

METHODS

Two independent blinded reviewers measured AAI using postinjury computed tomography scans. Patients were classified as having "severe" or "minimal" AAI on the basis of greater versus less than or equal to 50% mean subluxation across each C1-C2 facet joint. Rates of nonunion and mortality were compared using independent samples t tests and adjusted for age, displacement, and subtype using binary logistic regression.

RESULTS

One hundred seven patients had minimal AAI and 17 had severe AAI. Mean follow-up was 4.4 months (standard deviation=4.6). Patients with severe AAI were more likely to experience nonunion (29% vs. 10%, respectively; p=.03) and mortality (35% vs. 14%, respectively; p=.03) regardless of treatment modality. Fracture displacement correlated with AAI (r(2)=0.65). When adjusted for patient age, the odds ratio of nonunion with severe AAI approached significance at 3.3 (95% confidence interval [CI]: 0.9-11.7). Mortality prediction with AAI approached a twofold increased risk (odds ratio=2.1; 95% CI: 0.6-6.8). In patients with Type-II fractures, the odds of mortality with severe AAI approached a threefold higher risk (odds ratio=3.3; 95% CI: 0.9-12.3).

CONCLUSIONS

Patients with acute odontoid fractures and severe AAI may be more likely to experience nonunion and mortality, suggesting the possibility that aggressive management could be warranted. Further investigation with a large prospective study including patient-important functional outcomes is justified.

Anterior-only stabilization using cage versus plating with bone autograft for the treatment of type II/IIA Hangman's fracture combined with intervertebral disc injury

BACKGROUND

Anterior C2/3 discectomy and interbody fusion (ACDF) with plating is increasingly performed as the primary treatment of unstable Hangman's fracture; however, plate-related complications, such as screw back-out, plate fracture and soft-tissue injury, is not uncommon. Polyetheretherketone (PEEK) cage has now been developed to provide initial stability before fusion; however, whether and how ACDF with PEEK cage offer better clinical results compared with ACDF with plating in management of Hangman's fracture remains unknown. This study compares the efficacy of ACDF with plating to that of ACDF with PEEK cage in management of type II/IIA Hangman's fractures (according to Levine and Edwards classification) retrospectively.

METHODS

From February 2006 to March 2012, a total of 21 patients with type II/IIA Hangman's fractures combined with intervertebral disc injury underwent ACDF with PEEK cage, and 28 patients underwent ACDF with plating. Perioperative parameters were compared. The average follow-up period was 50.3 months (range 27-76 months). The clinical outcome (visual analog scale (VAS), American Spinal Injury Association (ASIA) scale, and clinical post-traumatic neck score (PTNC)) and radiological outcome (translation of C2, local kyphotic angle (LKA), and fusion status of C2/3) was compared retrospectively.

RESULTS

The operative time and blood loss were significantly less in the ACDF with cage group compared with that in the ACDF with plating group (P < 0.05). All patients showed neurological recovery and achieved solid fusion. There were no significant differences in the clinical and radiological outcomes at final follow-up between groups, except in the LKA and the correction loss rate of LKA which were higher in the ACDF with plating group (P < 0.05). Donor-site pain occurred in two patients (10.1%) within 6 months after operation in the ACDF with plating group and none in the ACDF with cage group. All patients recovered without any adverse effects.

CONCLUSIONS

ACDF with PEEK cage is effective and reliable in management of type II/IIA Hangman's fractures and is more cost-effective due to shorter operative time and less blood loss requirements.

Posterior reduction and temporary fixation for odontoid fracture: a salvage maneuver to anterior screw fixation

STUDY DESIGN

A prospective study.

OBJECTIVE

To evaluate the outcomes of posterior reduction and temporary fixation using the C1-C2 screw-rod system for odontoid fracture unsuitable for anterior screw fixation.

SUMMARY OF BACKGROUND DATA

Anterior screw fixation has become the most widely used surgical procedure for the stabilization of odontoid fractures. However, if there is any contraindication for anterior fixation, posterior atlantoaxial fusion is preferred, eliminating the normal rotation of the atlantoaxial complex.

METHODS

A consecutive series of 22 patients with odontoid fracture unsuitable for anterior screw fixation were involved in this study. Posterior reduction and fixation without fusion using the C1-C2 screw-rod system was performed. Once fracture healing was obtained, instrumentation was removed. The visual analogue scale of neck pain, neck stiffness, American Spinal Injury Association impairment scale, patient satisfaction, and neck disability index were recorded. The range of motion of C1-C2 in flexion-extension and rotation was calculated.

RESULTS

The average age at internal fixation surgery was 40.2±11.3 years. The mean duration of follow-up was 41.8±26.8 months. There were no complications associated with instrumentation. All patients returned to their preoperative work. Fracture healing was observed in 21 patients and the instrumentation was removed. After removing the instrumentation, the visual analogue scale was reduced and neck stiffness were relieved (all P<0.01). Patient satisfaction and neck disability index had improved (all P<0.01). The range of motion of C1-C2 returned to 4.75°±1.62° and 25.70°±5.51° in flexion-extension and in rotation, respectively. No osteoarthritis was observed at the C1-C2 lateral mass joints.

CONCLUSION

Posterior reduction and temporary fixation using the C1-C2 screw-rod system was an optimal salvage maneuver to anterior screw fixation for odontoid fracture. It could effectively avoid the motion loss of C1-C2 caused by posterior atlantoaxial fusion.

LEVEL OF EVIDENCE

3.

Odontoid balloon kyphoplasty associated with screw fixation for Type II fracture in 2 elderly patients

Anterior screw fixation is a well-recognized technique that is used to stabilize Type IIB fractures of the odontoid process in the elderly. However, advanced age and osteoporosis are 2 risk factors for pseudarthrosis. Kyphoplasty has been described in the treatment of lytic lesions in C-2. The authors decided to combine these 2 techniques in the treatment of unstable fractures of the odontoid. Two approximately 90-year-old patients were treated for this type of fracture. Instability was demonstrated on dynamic radiography in one patient, and the fracture was seen on static radiography in the other. Clinical parameters, pain, range of motion, 36-Item Short Form Health Survey (SF-36) score (for the first patient), and radiological examinations (CT scans and dynamic radiographs) were studied both before and after surgery. After inflating the balloon both above and below the fracture line, the authors applied a high-viscosity polymethylmethacrylate cement. Some minor leakage of cement was noted in both cases but proved to be harmless. The screws were correctly positioned. The clinical result was excellent, both in terms of pain relief and in the fact that there was no reduction in the SF-36 score. The range of motion remained the same. A follow-up CT scan obtained 1 year later in one of the patients showed no evidence of change in the materials used, and the dynamic radiographs showed no instability. This combination of kyphoplasty and anterior screw fixation of the odontoid seems to be an interesting technique in osteoporotic Type IIB fractures of the odontoid process in the elderly, with good results both clinically and radiologically.

Traction Induced Vertical Displacement of Odontoid due to Type III Odontoid Fracture with Unrecognized Ligamentous Injury: A Case Report

Dens fractures are a common traumatic cervical spine injury. Among them, a type III fracture is the second common fracture. Although there are several treatment options, it has been accepted that type III fracture is usually healed by non-surgical method. After adequate reduction with traction, subsequent external immobilization has been associated with successful union rates. However, in the review of literatures, there are some cases with neurological deterioration after application of skull traction. So, the authors report a case of type III dens fracture with initially unrecognized ligamentous injury in which vertical dissociation and quadriplegia occurred after only five-pound Gardner-Well tongs traction. And also, the authors raise awareness of this potentially injury.

Incidence and cost of treating axis fractures in the United States from 2000 to 2010

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

To examine the incidence of hospitalization, treatment, and cost of caring for patients with axis (C2) fractures.

SUMMARY OF BACKGROUND DATA

The incidence of C2 fractures in the elderly seems to be increasing, however, a comprehensive analysis of the incidence, treatment, and cost of treating C2 fractures has not been previously reported.

METHODS

The Nationwide Inpatient Sample from 2000 to 2010 was used to identify patients with C2 fracture without neurological injury (International Classification of Disease, Ninth Revision, Clinical Modification code 805.02). Examined variables included age, International Classification of Disease, Ninth Revision, Clinical Modification injury severity score, comorbidities, mortality, hospital length of stay, treatments, and total inpatient hospitalization charge. Charges were adjusted for inflation to 2010 US dollars as well as for cost-to-charge ratios.

RESULTS

In total, 31,129 patients with C2 fracture were identified. From 2000 to 2010 the incidence of C2 fracture hospitalization increased in all age groups (P < 0.0001). The most rapid increase was in patients older than 84 years, who experienced a 3-fold increase from 3.18 to 9.77 hospitalizations per 10,000 individuals per year (P < 0.0001). From 2000 to 2010, the rate of halo vest placement decreased from 25.2% to 10.4% (P < 0.0001), whereas the rate of surgical intervention increased from 13.1% to 16.5% (P = 0.029). For nonoperatively treated patients, the mean hospitalization charge per patient increased from $39,346 in 2000 to $63,222 in 2010, and for surgically treated patients, it increased from $70,784 in 2000 to $133,064 in 2010 (P < 0.0001). During the decade, the estimated charges for annual inpatient care for patients with C2 fracture in the United States increased 4.7-fold from $334,138,919 to $1,577,254,958 (P < 0.0001).

CONCLUSION

The incidence of C2 fracture hospitalizations increased dramatically from 2000 to 2010, with the most rapid increase in the elderly represented by a greater than 3-fold increase for patients older than 84 years. The inpatient charges for treating C2 fractures have risen faster than the increased incidence, with a 4.7-fold increase in hospital charges resulting in estimated annual charges of more than $1.5 billion in 2010.

LEVEL OF EVIDENCE

3.

[Anterior odontoid screw fixation using intra-operative cone-beam computed tomography and navigation]

OBJECTIVE

The purpose of this study was to asses the value of intraoperative cone-beam CT (O-arm) and stereotactic navigation for the insertion of anterior odontoid screws.

MATERIALS AND METHODS

this was a retrospective review of patients receiving surgical treatment for traumatic odontoid fractures during a period of 18 months. Procedures were guided with O-arm assistance in all cases. The screw position was verified with an intraoperative CT scan. Intraoperative and clinical parameters were evaluated. Odontoid fracture fusion was assessed on postoperative CT scans obtained at 3 and 6 months' follow-up

RESULTS

Five patients were included in this series; 4 patients (80%) were male. Mean age was 63.6 years (range 35-83 years). All fractures were acute type ii odontoid fractures. The mean operative time was 116minutes (range 60-160minutes). Successful screw placement, judged by intraoperative computed tomography, was attained in all 5 patients (100%). The average preoperative and postoperative times were 8.6 (range 2-22 days) and 4.2 days (range 3-7 days) respectively. No neurological deterioration occurred after surgery. The rate of bone fusion was 80% (4/5).

CONCLUSION

Although this initial study evaluated a small number of patients, anterior odontoid screw fixation utilizing the O-arm appears to be safe and accurate. This system allows immediate CT imaging in the operating room to verify screw position.