Pooled analysis of non-union, re-operation, infection, and approach related complications after anterior odontoid screw fixation

Surgeon Experience Is the Most Important Predictor of Case Failure Rate for Anterior Odontoid Screw Fixation: A Large Database Study

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

Determine risk factors and failure rate of anterior odontoid screw fixation surgery.

SUMMARY OF BACKGROUND DATA

Anterior odontoid screw fixation (AOSF) stabilizes type II dens fractures while preserving cervical motion. Despite having potential advantages, AOSF's failure rate and factors contributing to failure remain unknown.

MATERIALS AND METHODS

We identified AOSF patients in the national claims database Pearldiver using CPT code 22318. Failure was defined as the requirement of supplementary posterior fusion surgery in the C1-C2 or occiput-C2 region after the AOSF. We considered potential predictors of failure including age, sex, Charlson Comorbidity Index (CCI), surgeon experience, history of osteoporosis, obesity, and tobacco use. Univariate comparison analysis and logistic regression were conducted to identify factors associated with the need for additional posterior surgery.

RESULTS

For 2008 identified cases of AOSF, 249 cases (12.4%) required additional posterior fusion. Seventy-one of the 249 cases (28.5%) underwent revision surgery on the same day as the AOSF. Over 86% of revisions (215 cases) occurred within 200 days of the initial procedure. Posterior fusion rates are inversely correlated with surgeon experience, with the most experienced surgeons having a rate of 10.0%, followed by 11.5% for moderately experienced surgeons, and 15.0% for the least experienced surgeons. When comparing moderate and inexperienced surgeons to experienced surgeons, the odds ratios for posterior fusion were 1.18 ( P >0.05) and 1.61 ( P <0.006), respectively. Logistic regression revealed that both lesser experience (odds ratio=1.50) and osteoporosis (odds ratio=1.44) were the only factors significantly associated with failure ( P <0.05).

CONCLUSIONS

Our findings indicate a correlation between AOSF success and surgeon experience. While currently published results suggest higher success rates, most of this data originates from experienced surgeons and specialized centers, therefore, they may not accurately reflect the failure rate encountered in a more general practice setting.

LEVEL OF EVIDENCE

Level III.

Using Frailty Measures to Predict Functional Outcomes and Mortality After Type II Odontoid Fracture in Elderly Patients: A Retrospective Cohort Study

STUDY DESIGN

Single-center retrospective cohort study.

OBJECTIVES

Type II odontoid fractures occur disproportionately among elderly populations and cause significant morbidity and mortality. It is a matter of debate whether these injuries are best managed surgically or conservatively. Our goal was to identify how treatment modalities and patient characteristics correlated with functional outcome and mortality.

METHODS

We identified adult patients (>60 years) with traumatic type II odontoid fractures. We used multivariate regression controlling for patient demographics, Glasgow Coma Scale (GCS) score, Charlson Comorbidity Index (CCI), modified Rankin Scale (mRS) score, modified Frailty Index (mFI-5 and mFI-11), fracture displacement, and conservative vs operative treatment.

RESULTS

Of the 59 patients (mean age 77.9 years), 24 underwent surgical intervention and 35 underwent conservative management. Operatively managed patients were younger (73.4 vs 80.6 years, P < .001) and had higher degree of fracture displacement (3.5 vs 1.0 mm, P = .002) than conservatively managed patients but no other differences in baseline characteristics. Twenty-four patients (40.7%) died within the study period (median time to death: 376 days). There were no differences between treatment groups in functional outcomes (mRS or Frankel Grade) or mortality (33.3% in operative group vs 45.7%, P = .34). There was a statistically significant correlation between higher presentation mRS score and subsequent mortality on multivariate analysis (OR = 2.06, 95% CI 1.04-4.10, P = .039), whereas surgical intervention, age, GCS score, CCI, mFI-5, mFI-11, sex, and fracture displacement were not significantly correlated.

CONCLUSIONS

Mortality after type II odontoid fractures in elderly patients is common. mRS score at presentation may help predict mortality more accurately than other patient factors.

Early Extrusion of an Anterior Odontoid Screw: A Case Report

Odontoid fractures in the elderly typically require surgical intervention due to poor adaptability to conservative treatment. Anterior screw fixation, despite its high fusion rates under specific conditions, may lead to complications such as screw extrusion, as demonstrated in the case discussed, necessitating subsequent posterior cervical fusion. This study aimed to describe early extrusion of an anterior odontoid screw and the importance of caution and thorough postoperative assessment in elderly patients undergoing anterior screw fixation for odontoid fracture. A 73-year-old female patient with a history of ground-level fall and subsequent cervical pain was diagnosed with an odontoid type II fracture and underwent odontoid screw placement in June 2023. However, in August, follow-up imaging revealed screw displacement and a fracture of the posterior arch of the C1 vertebral, which was initially overlooked. After seeking a second opinion, a new surgical approach was decided, involving removal and replacement of the odontoid screw, posterior and posterolateral C1-C2 spinal instrumentation, arthrodesis, and fusion with the use of morselized allograft. The patient was discharged on postoperative day 3 with mild cervical pain, wearing a soft collar, and neurologically intact. Given the current literature, odontoid screw extrusion rates are still small but can come with enormous potential complications. Also, the present case is a reminder to always double-check preoperative imaging and recognize early failure/malpositioning of hardware.

Short-term and long-term results of odontoid screw fixation in patients with Type II and rostral Type III dens fractures

OBJECTIVES

To evaluate both the short-term and long-term outcomes of odontoid screw fixation (OSF), identifying potential risk factors for implant-related complications in patients with odontoid fractures.

METHODS

This is a retrospective observational cohort study. Inclusion criteria were as follows: 1) Type II fractures and rostral Type III fractures, according to the Anderson and D'Alonzo classification; 2) patients older than 15 years. Exclusion criteria were: 1) other Type III injuries; 2) osteoporosis confirmed by densitometry or a CT bone density score below 100 Hounsfield units; 3) odontoid fractures related to tumors or aneurysmal bone cysts.

RESULTS

In total, 56 patients were considered for the analysis of short-term results, and 26 patients were evaluated for long-term outcomes. No significant differences were observed in the preoperative imaging data and intraoperative features of OSF between patients with Type II and rostral Type III fractures. The mean operative duration was 63.9 ± 20.9 min, and the mean intraoperative blood loss was 22.1 ± 22.9 ml. Screw cut-out was identified in four patients with rostral Type III fractures (p = 0.04). The rate of screw cut-out was found to correlate with the degree of dens fragment displacement. The bone fusion rate was 95.7%. CT scans identified stable pseudarthrosis in two cases. We observed C2-C3 ankylosis in all cases following partial disc resection. One third of patients with screws placed through the anterior lip of C2 showed no C2-C3 ankylosis. A strong trend towards lateral joint ankylosis formation in patients with a median lateral mass dislocation of 11.9 mm was observed. Most SF-36 scores either matched or exceeded the corresponding normal median values in the published reference database.

CONCLUSIONS

OSF is a reliable treatment method of Type II and rostral Type III odontoid fractures with fragment displacement of 4 mm or less. The minimally invasive OSF through the anterior-inferior lip of C2, using monocortical screw placement and cannulated instruments, without rigid intraoperative head immobilization, is sufficient to achieve favorable clinical and fusion results. This technique reduces the risk of ankylosis in the C2-C3 segment. OSF restore the quality of life for patients with odontoid fractures to levels comparable to those of the general population norm.

MFI-11 Predicts Post-Operative Serious Complications in Patients Undergoing Surgery for Odontoid Fractures

STUDY DESIGN

Retrospective Cohort.

OBJECTIVES

The objective of this study was to analyze postoperative complications in different mFI-11 groups after surgery for odontoid fractures in a geriatric population.

METHODS

A single center retrospective review of odontoid fractures surgery (between 2013 and 2022) in patients aged 65 years and older was conducted. The primary outcome was the occurrence of a major complication (Calvien-Dindo ≥4) within 30 days post-surgery. The secondary outcome was the occurrence of a major complication within 3 months after surgery, and death within 1-month post-surgery. Survival curve, multi-variate analysis was performed and adjusted receiver operating characteristic curves were generated.

RESULTS

There were 92 patients included in this study, with a mean age of 80.5 years. Serious complication occurred for 16 patients (17%) during hospitalization. Multivariate analysis demonstrated an mFI 11 >.27 was strongly and independently associated with serious complications within 1-month post-surgery (OR = 16.7, 95% CI = 4.50-83), as well as serious complications within 3 months post-surgery (OR = 11.8, 95% CI = 3.48-49.1) and death within 1 month post-surgery (OR = 11.7; 95% CI = 3.02-60.4). The Receiver Operator Characteristics (ROC) curves for the three models all have an Area Under the Curve (AUC) value greater than 0.7.

CONCLUSIONS

The mFI-11 is a straightforward and validated tool that can be used during the preoperative period to identify the patient's level of frailty and assess their risk of postoperative complications. Patients with mFI-11 ≥.27 are at greater risk of serious complications within 1 and 3 months' post-surgery and death within 1 month post-surgery.

Type II Odontoid Fractures: Is the Anterior Screw a Good Solution for all Patients? A Case Series of 60 Consecutive Patients

OBJECTIVE

Type II odontoid fracture is the most common fracture type, and its treatment remains challenging. The objective of this study was to evaluate the results of anterior screw fixation for type II odontoid fractures in patients aged over and below 60 years.

METHODS

A retrospective analysis of consecutive patients diagnosed with type II odontoid fractures who were surgically treated using the anterior approach by a single surgeon was conducted. Demographic characteristics, including age, sex, type of fracture, time from trauma to surgery, length of stay (LoS), fusion rate, complications, and reoperation, were evaluated. Surgical outcomes were compared between patients over and below 60 years of age.

RESULTS

Sixty consecutive patients underwent odontoid anterior fixation during the analysis period. The mean age of patients was 49.58 ± 23.22 years. Twenty-three (38.3%) patients were aged over 60 years, and the minimum follow-up period was two years. Of the patients, 93.3% developed bone fusion, which was observed in 86.9% of patients over 60 years. Complications related to hardware failure occurred in six (10%) patients. Transient dysphagia was observed in 10% of the cases. Three (5%) patients required reoperation. Patients over 60 years had a significantly increased risk of dysphagia compared with those below 60 years (P = 0.0248). There was no significant difference between the groups regarding nonfusion rate, reoperation rate, or LoS.

CONCLUSIONS

Anterior fixation of the odontoid showed high fusion rates with a low rate of complications. It is a technique to be considered for treating type II odontoid fractures in selected cases.

Modified anterior transarticular C1/2 fixation for odontoid fractures: An approach with high complication rate in geriatric population

Background:

In patients over 75 years of age, we applied a modified anterior transarticular C1/2 fixation with reduced pharyngeal mobilization versus the standard anterior triple/quadruple osteosynthesis procedures.

Methods:

From 2010 to 2018, 29 patients underwent a modified anterior transarticular C1/2 fixation utilizing single odontoid screw fixation through a right-sided Smith-Robinson – (i.e., short and steep screw trajectory for the right and long trajectory for the left side) approach. All the patients were 75 years of age or older (mean age 82.6) and had sustained odontoid Type II fractures. In addition, a subset exhibited further ligamentous injuries and/or atlas fractures. Their Mean Age-adjusted Charlson Comorbidity Index was 5.3 points (range 3–12), while mean American Society of Anesthesiologists scores averaged 2.9 (range 2–4).

Results:

The mean operating time was 55.8 min, there were no intraoperative complications, and there was minimal blood loss in all cases. The most common medical complications included aspiration pneumonia (24.1%, n = 7), altered mental status (17.2%, n = 5), and cardiac decompensation (6.9%, n = 2). One patient with delayed dysphagia and an infected implant resulting in loosening/dislocation required implant removal and long-term antibiotic therapy. The 30-day mortality rate was 13.8% (four patients) and the 1-year mortality rate was 27.6% (eight patients).

Conclusion:

Anterior transarticular C1/2/odontoid fixation with reduced pharyngeal mobilization and shorter operative times was associated with high morbidity/mortality rates. Dysphagia/aspiration was the major postoperative complications leading to some deaths especially in patients with dementia/Parkinsonism.

A True Percutaneous Anterior Odontoid Screw Fixation: The Results of 42 Cases by a Single Surgeon

OBJECTIVE

This study aimed to analyze a clinical series of odontoid fractures treated with true percutaneous anterior odontoid screws. The technique we used is different from the traditional approach of using blunt dissection to arrive at the anterior surface of the vertebral body.

METHODS

Between 2004 and 2021, forty-two patients underwent anterior screw fixation of the odontoid process using the true percutaneous technique without dissection among the fascial planes. Instead, we pressed from the medial border of the sternocleidomastoideus muscle with our second and third fingers to feel the vertebrae under the skin. Thus, the carotid artery is pushed laterally, the trachea-esophageal complex is moved medially, and when no esophagus, great vessels, etc., can be felt under our fingers; we have reached the anterior surface of the spine. Advancing the Jamshidi needle between the fingers causes it to pass only through the fascial layers. The absence of a gap between the dilatation tubes prevents any tissue from escaping into the tubes.

RESULTS

We had no intraoperative complications, such as esophageal, tracheal, or carotid injury. One patient required screw revision. In total, 5 patients died during the follow-up period, and 3 were lost to follow-up. There was no residual neck pain in our cohort, and no instability was noted on flexion-extension radiographs, even in ten patients without solid bone fusion.

CONCLUSIONS

True percutaneous anterior odontoid screw fixation is a safe and reliable procedure for treating odontoid fractures. The fibrous union of odontoid fractures provides as much stability as a solid bone fusion.

Odontoid Fractures: A Standard Review of Current Concepts and Treatment Recommendations

Odontoid fractures represent the most common fractures involving C2 and the most common cervical spine fractures in patients older than 65 years. Despite their increasing frequency, optimal management of these injuries remain a subject to debate. Although types I and III injuries have relatively good healing potential with nonsurgical treatment, type II fractures carry a higher risk for nonunion. In particular, elderly patients are at risk for nonunion or fibrous malunion after nonsurgical treatment; however, increased medical comorbidities and poor bone quality also increase the risks of surgery in this cohort. The high morbidity and mortality associated with these injuries has made it an area of particular interest among spine surgeons. The purpose of this review was to summarize the pathophysiology, evaluation, and diagnosis of these injuries and to review controversies in management and considerations for treatment based on the most recent available literature.

Odontoid Type II fractures in elderly: what are the real management goals and how to best achieve them? A multicenter European study on functional outcome

Odontoid fractures constitute the most common cervical fractures in elderly. External immobilization is the treatment of choice for Type I and III; there is still no wide consensus about the best management of Type II fractures. Observational multicenter study was conducted on a prospectively built database on elderly patients (> 75 years) with Type II odontoid fracture managed conservatively during the last 10 years. All patients underwent CT scan on admission and at 3 months; if indicated, selected patient had CT scan at 6 and 12 months. All patients were clinically evaluated by Neck Disability Index (NDI), Charlson Comorbidity Index (CCI), and American Society of Anaesthesiologists classification (ASA) on admission; NDI was assessed also at 6 weeks, 3, 6, 12, and 24 months; furthermore, a quality of life (QoL) assessment with the SF-12 form was performed at 3 and 12 months. Among the 260 patients enrolled, 177 (68%) were women and 83 (32%) men, with a median age of 83 years. Patients were followed up for a minimum of 24 months: 247 (95%) showed an excellent functional outcome within 6 weeks, among them 117 (45%) showed a good bony healing, whereas 130 (50%) healed in pseudo-arthrosis. The residual 5% were still variably symptomatic at 12 weeks; however, only 5 out of 13 (2% of the total cohort) required delayed surgery. This study showed that a conservative approach to odontoid Type II fracture in elderly is an effective and valid option, resulting in an excellent functional outcome (regardless of bony fusion) in the majority of cases. Failure of conservative treatment can be safely addressed with surgical fixation at a later stage.

Anterior Odontoid Screw Fixation for C2 Fractures: Surgical Nuances, Complications, and Factors Affecting Fracture Union

OBJECTIVE

Type II odontoid fractures are the commonest C2 fractures. The management of dens fractures remains controversial with various radiological and fracture morphological factors affecting the approach and outcomes.

METHODS

All cases of anterior odontoid screw fixation between 2010 and 2020 were retrospectively analyzed. Patients' clinical, radiological (type of fracture, orientation, displacement, and diastasis), operative (single vs. double screw) and follow-up records were documented. The postoperative imaging findings were classified into grades I (excellent), II (good), and III (poor) based on the anatomical alignment with the screw. Follow-up cervical computed tomography was reviewed for fracture union.

RESULTS

A total of 49 patients with a mean age of 37.3 ± 13.8 years were included in the study. The average time from injury to surgery was 23.1 ± 22.2 days. The bicortical screw purchase and superoposterior odontoid tip breach significantly affected the postoperative alignment (P = 0.035 each). Fracture union was noted in 41 (83.7%) patients. The horizontal fracture displacement ≥2.5 mm (P = 0.02) and poor postoperative fracture alignment (P < 0.001) resulted in worse fracture union rates. Transient dysphagia was the commonest complication (n = 12), whereas screw breakout (n = 2) and pullout (n = 2) were other hardware-related complications. One patient underwent re-exploration for screw readjustment and 2 underwent posterior instrumentation.

CONCLUSIONS

Anterior odontoid screw fixation is technically straightforward, less morbid, and preserves biomechanical cervical mobility, when compared with the posterior instrumentation. With careful patient selection, meticulous surgical planning, and intraoperative image-guided screw insertion, good fracture union outcomes can be obtained. In the current study, we were able to achieve stable fracture union in 83.7% patients.

Determination and optimization of ideal patient candidacy for anterior odontoid screw fixation

Background:

Odontoid process fractures are one of the most common spine fractures, especially in patients over age 70. There is still much controversy over the ideal candidate for anterior odontoid screw fixation (AOSF), with outcomes affected by characteristics such as fracture morphology, nonideal body habitus, and osteoporosis. Therefore, this systematic review seeks to discuss the optimal criteria, indications, and adverse postoperative considerations when deciding to pursue AOSF.

Methods:

This investigation was conducted from experiential recall and article selection performed using the PubMed electronic bibliographic databases. The search yielded 124 articles that were assessed and filtered for relevance. Following the screening of titles and abstracts, 48 articles were deemed significant for final selection.

Results:

AOSF is often utilized to treat Type IIB odontoid fractures, which has been shown to preserve atlantoaxial motion, limit soft-tissue injuries/blood loss/vertebral artery injury/reduce operative time, provide adequate osteosynthesis, incur immediate spinal stabilization, and allow motion preservation of C1 and C2. However, this technique is limited by patient characteristics such as fracture morphology, transverse ligament rupture, remote injuries, short neck or inability to extend neck, barrel chested, and severe spinal kyphosis, in addition to adverse postoperative outcomes such as dysphagia and vocal cord paralysis.

Conclusion:

Due to the fact that odontoid fractures have a significant morbidity in elderly population, treatment with AOSF is generally recommended for this population with higher risk for nonoperative fusion. Considerations should be made to achieve fracture stability and fusion, while lowering the risk for operative and postoperative complications.

Clinical and radiological outcome after minimally invasive surgical approach for type II unstable odontoid fractures

INTRODUCTION

Anterior odontoid screw fixation is a valid surgical option for unstable odontoid fractures, as type II Anderson D'Alonzo fractures. Grauer further divided type II fractures in subtypes according to the fracture line, providing recommendations for implementation of screw fixation techniques.

OBJECTIVE

Primary endpoint of our study is to evaluate the postoperative results of minimally invasive odontoid screw insertion in terms of outcome, fusion rate and stability of cranio-cervical junction. Secondary endpoint was to investigate the influence of age or fractures' features on outcome and fusion rate.

MATERIALS AND METHODS

We report the clinical and radiological features of 32 patients harbouring unstable type II fractures operated by a minimally invasive odontoid screw insertion technique. All patients underwent a high resolution multiplanar CT in order to assess fracture features according to Grauer's classification; the integrity of ligaments was investigated by MRI. In addition, a preoperative neurological performance (modified Rankin Scale, mRS) was evaluated for patients either directly or interviewing their families. Follow-up at one, three and six months and 1 year have been performed (averaging 13.5 months) by cervical CT (fusion rate and stability) and mRS update. In order to investigate the influence of age on postoperative neurological performance, two groups (≤50 yrs, 9 pts/>50 yrs, 23 pts) were separately considered and analysed. Overall, we observed no surgery related complications. We also analysed the fusion rate and its correlation with patient age and Grauer's subtype of fracture.

RESULTS

At last available clinical follow-up, the preoperative performance was preserved (mRS 0/1: 24, 75%; mRS 2-4: 9, 15%) although with slight reduction of intact patients (mRS 0: 22 vs. 19; 71.8 vs. 59.3%). Younger patients (≤50 yrs) fared significantly better than older ones, achieving a good clinical outcome (mRS 0/1) in 100% vs. 69.5% (9/9 vs. 16/23 pts). Statistical analysis showed a fair correlation between age and outcome. Other factors such as sex and Grauer's type did not influence significantly the clinical outcome. Nine patients did not complete a full radiological follow-up and were therefore excluded from analysis of radiological outcome. Among the remaining 23 patients, only 25% of those who were followed three months or less showed fusion; conversely, all patients who have been examined from 6 to 48 months fused. Among the non-union patients, two underwent a second surgery by posterior approach.

CONCLUSIONS

In our recent experience, the minimally invasive AOSF proved safe and effective in treating odontoid peg fractures. Selection based on Grauer's type is mandatory to achieve best results. While in the elderly, an anterior approach is well accepted as the first choice treatment, we recommend that this option should be offered as a suitable alternative to Halo or orthosis also in younger patients since it provides prompt, excellent clinical outcome and high fusion rate especially in this age group.

Early mortality and morbidity of odontoid fractures after 70 years of age

INTRODUCTION

Odontoid fractures are very common in older adults and are associated with a high mortality rate. The aim of this study was to evaluate the outcomes after conservative treatment of non-displaced odontoid fractures and surgical treatment of displaced fractures in patients older than 70 years. It was hypothesized that early mortality of displaced fractures is higher than in non-displaced fractures.

MATERIAL AND METHODS

This was a single-center retrospective observational study of odontoid fractures (type II in the Anderson and Alonzo classification) in patients older than 70 years that occurred between 2014 and 2017. Conservative treatment with immobilization for 3 months was proposed when the fracture was displaced less than 2 mm (non-displaced fracture group). Surgical treatment in the form of anterior screw fixation was proposed when the fracture displacement was more than 2 mm (displaced fracture group). The primary endpoint was the mortality rate at 3 months.

RESULTS

The study included 79 patients (46 women) who had a mean age of 85 years (70-105). The 3-month mortality in the entire cohort was 27% and the 1-year mortality was 30%. Conservative treatment was provided to the 36 patients with non-displaced fractures. The 3-month mortality rate in this group was 11%. A displaced fracture occurred in 43 patients: 17 were treated surgically by anterior screw fixation; 20 could not be operated on because of anesthesia contraindications and 6 died within 24hours of the fracture event. The 3-month mortality rate in this group was 40%; 3 of the 17 operated patients died from postoperative respiratory complications; 8 of the 20 patients with contraindications died, in addition to the 6 that died soon after the fracture occurred.

DISCUSSION

This study confirms that mortality and morbidity are high following odontoid fractures. The mortality rate was significantly higher in patients with displaced fractures, confirming our hypothesis. The mortality rate was especially high when patients with displaced fractures could not undergo surgery because of anesthesia contraindications. Also, there was a high rate of respiratory complications after anterior screw fixation of displaced fractures.

CONCLUSION

Given our findings, conservative treatment should be compared to surgical treatment for displaced fractures and the anterior approach should be compared to the posterior one for surgical cases.

LEVEL OF EVIDENCE

IV.

The Anterior Transarticular Fixation of C1/C2 in the Elderly With Dens Fractures

Background

Anterior transarticular screw fixation (ATSF) of C1/C2 can be used for the treatment of unstable dens fractures. Here, we evaluated the feasibility of an anterior C1/C2 fixation in elderly patients with unstable dens fractures. Furthermore, we tried to analyze safe entry zones for ATSF surgery.

Methods

A consecutive cohort of 13 patients with unstable dens fractures were treated with ATSF of C1/C2 between January 2015 and October 2016. If necessary, an additional screw was placed into the odontoid process. The placement was radiographically analyzed using the 3D Arcadis Orbic (Siemens, Erlangen, Germany). Additionally, computed tomography scans of the cervical spine from 50 trauma patients were analyzed to evaluate safe entry zones for anterior odontoid screw fixation and for ATSF.

Results

ATSF was performed in 13 cases (7 female, 6 male; mean age 81.80 years). One screw had to be corrected intraoperatively due to initial malplacement. Neurological deficits or an injury of the vertebral artery were not observed. All patients suffered from swallowing difficulties during the postoperative course, without lesions of the esophagus or the trachea. In 4 patients (30.8%), an additional posterior fixation was offered to the patients due to progressive loosening of the screws.The anatomical-radiographic analyzes revealed a significantly shallower angle of trajectory for anterior odontoid screw fixation (24.9° ± 5.85°) than for ATSF (39.1° ± 6.44° (left); 40.5° ± 6.79° (right) P = 0.02).

Conclusions

The ATSF of C1/C2 might be a valuable option in the treatment of instable C1/C2 fractures, especially in the elderly or in patients with short necks and/or high body mass index due to the steeper trajectory compared with odontoid screw placement. Yet available screws seem to be of inferior resistance compared with the biomechanical properties of a dorsal fixation. Further studies should focus on screws with better mechanical properties and probably additional cement augmentation.

Level of Evidence

4.

Progress of the Anterior Transpedicular Screw in Lower Cervical Spine: A Review

The anterior transpedicular screws (ATPS) fixation is a valuable discovery in the field of lower cervical spine (LCS) reconstruction, as it has the advantages of both anterior and posterior approaches. In recent years, with in-depth research on ATPS fixation related to anatomy, biomechanical tests, and clinical applications, its firm stability and excellent biomechanical properties have been recognized by more and more surgeons. Although ATPS fixation has been gradually applied in clinic settings under the promotion of emerging distinctive instruments, its long-term efficacy still needs to be further clarified due to the lack of large sample size studies and long-term follow-up. Nevertheless, it is believed that with the maturity of digital devices and the development of precision medicine, ATPS fixation has a promising prospect.

Mortality, complication, and fusion rates of patients with odontoid fracture: the impact of age and comorbidities in 204 cases

PURPOSE

The French Society of Spine Surgery (SFCR) conducted a prospective epidemiologic multicenter study. The purpose was to investigate mortality, complication, and fusion rates in patients with odontoid fracture, depending on age, comorbidities, fracture type, and treatment.

METHODS

Out of 204 patients, 60 were ≤ 70 years and 144 were > 70 years. Demographic data, comorbidities, treatment types and complications (general medical, infectious, neurologic, and mechanical), and death were registered within the first year. Fractures were classified according to Anderson-D'Alonzo and Roy-Camille on the initial CT. A 1-year follow-up CT was available in 144 patients to evaluate fracture consolidation.

RESULTS

Type II and oblique-posterior fractures were the most frequent patterns. The treatment was conservative in 52.5% and surgical in 47.5%. The mortality rate in patients ≤ 70 was 3.3% and 16.7% in patients > 70 years (p = 0.0002). Fracture pattern and treatment type did not influence mortality. General medical complications were significantly more frequent > 70 years (p = 0.021) and after surgical treatment (p = 0.028). Neurologic complications occurred in 0.5%, postoperative infections in 2.0%, and implant-related mechanical complications in 10.3% (associated with pseudarthrosis). Fracture fusion was observed in 93.5% of patients ≤ 70 years and in 62.5% >70 years (p < 0.0001). Pseudarthrosis was present in 31.5% of oblique-posterior fractures and in 24.3% after conservative treatment.

CONCLUSIONS

Age and comorbidities influenced mortality and medical complication rates most regardless of fracture type and treatment choice. Pseudarthrosis represented the main complication, which increased with age. Pseudarthrosis was most frequent in type II and oblique-posterior fractures after conservative treatment.

Type II Odontoid Fracture: a case series highlighting the treatment strategies

BACKGROUND

A type II odontoid fracture, if unstable, can cause spinal cord damage. In this case, it is essential to choose the correct treatment-but the issues of what the correct treatment is and which of the different surgical options is best are quite controversial. In this paper we present strategies for treatment of type II odontoid fracture.

MATERIALS AND METHODS

Thirty consecutive cases of type II odontoid fracture were treated at the Division of Neurosurgery at Villa Sofia Hospital in Palermo (23 cases) and at the Neurosurgical Clinic, University Hospital of Palermo (seven cases), from January 2011 to August 2016. Four patients were treated with external immobilization. Twenty-six patients underwent a surgical procedure.

RESULTS

There was no mortality related to the surgical procedure. One patient had a pre- and postoperative neurological deficit, and remained tetraparetic. Follow-up radiological studies in the surgically treated group showed bone union in 21 patients and stable fibrous union in one.

CONCLUSION

In our and other authors' experience, when the direction of the fracture line is down and forward, external immobilization can be sufficient for healing. Anterior odontoid screw fixation can be considered the treatment of choice for unstable odontoid fractures (with a horizontal, down and back, or comminuted fracture line) without dislocation or with dislocation less than 7 mm.When the odontoid fracture is associated with a Jefferson fracture or dislocation greater than 7 mm, stabilization of C1-C2 may be necessary. In this case, placement of screws in the dens and in the joints through a single approach represents the most valid technique.In the case of an inveterate fracture of the dens with severe C1-C2 dislocation, the surgical operation that offers the best prospects is posterior stabilization, utilizing the Guo technique.

Odontoid fractures in combination with C1 fractures in the elderly treated by combined anterior odontoid and transarticular C1/2 screw fixation

INTRODUCTION

The purpose of this study was to evaluate risk factors of accompanied C1 fractures in elderly patients with type II odontoid fractures (OF) and to analyze the complication rate and the outcomes of patients after combined anterior odontoid and transarticular C1/2 screw fixation (AOTAF).

MATERIALS AND METHODS

The study represents a retrospective case series at a single level-1 trauma center. All elderly patients (≥ 70 years) with acute combination injuries (CI) including type II OF with an accompanied C1 fracture, who were treated by an anterior approach, were included. All postoperative complications were analyzed based on the patient notes. Clinical and radiological controls were performed after 1 year. Main parameters of interest were 1-year mortality rate, pain level, and satisfaction rate after 1 year.

RESULTS

A total of 23 patients were included. The average age was 84.6 years (range 73-94 years). All patients had atlanto-odontoid osteoarthritis (AOO) and all but two patients were injured by low-energy falls. Dysphagia was the most common postoperative complication (26.1%). Surgical revision was necessary in one of these patients due to hematoma. Dysphagia improved in all patients considerably. Loss of follow-up was 21.7%. The 1-year mortality was 21.7% (n = 5). The mean pain level and satisfaction rate was 2.5 (± 0.9) and 7.3 (± 0.7), respectively. After 1 year, no signs of non-union were visible.

CONCLUSIONS

AOO was observed in all patients with CI. The main cause of trauma was a low-energy fall. The pain levels were low to moderate and satisfaction levels were promising 1 year after surgery. Nonetheless, AOTAF is associated with a high rate of postoperative dysphagia, which resolves in the majority of patients due to conservative management.

Biomechanical comparison of cemented versus non-cemented anterior screw fixation in type II odontoid fractures in the elderly: a cadaveric study

BACKGROUND CONTEXT

Odontoid process fractures are the most common injuries of the cervical spine in the elderly. Anterior screw stabilization of type II odontoid process fractures improves survival and function in these patients but may be complicated by failure of fixation.

PURPOSE

The present study aimed to determine whether cement augmentation of a standard anterior screw provides biomechanically superior fixation of type II odontoid fractures in comparison with a non-cemented standard screw.

STUDY DESIGN

Twenty human cadaveric C2 vertebrae from elderly donors (mean age 83 years) were obtained.

METHODS

Anderson and D'Alonzo type IIa odontoid fracture was created by transverse osteotomy, and fluoroscopy-guided anterior screw fixation was performed. The specimens were divided into two matched groups. The cemented group (n=10) had radiopaque high viscosity polymethylmethacrylate cement injected via Jamshidi needle into the base of the odontoid process. The other group was not augmented. A V-shaped punch was used for loading the odontoid in an anteroposterior direction until failure. The failure state was defined as screw cutout or 5% force decrease. Mean failure load and bending stiffness were calculated.

RESULTS

The mean failure load for the cemented group was 352±12 N compared with 168±23 N for the non-cemented group (p<.001). The mean initial stiffness of the non-cemented group was 153±19 N/mm compared with 195±29 N/mm for the cemented group (p<.001) CONCLUSIONS: Cement augmentation of an anterior standard screw fixation of type II odontoid process fractures in elderly patients significantly increased load to failure under anteroposterior load in comparison with non-augmented fixation. This may be a valuable technique to reduce failure of fixation.

Development and Application of a No-Clog Surgical Suction Tip Using 3D Printing Technology

Background

Clogging of the suction tip frequently occurs during orthopedic surgery. We developed a novel anti-clog suction tip using 3D printing technology to improve orthopedic surgery efficiency.

Material/Methods

We studied the root causes of obstructions in suction tips currently employed in orthopedic surgery during actual surgical cases. CAD software and 3D printer was used to design, modify, and print the novel suction tip. The frequency of clogging, the frequency of replacement of the suction tip, the time lost in replacing suction tips or connecting tubes, surgical duration, intraoperative surgical blood loss, and the satisfaction scores for the suction tips as rated by the surgeons were compared between the novel suction tip and the conventional suction tip. Comparisons were made first in laboratory experiments using a simulant liquid and then during total hip replacement surgeries.

Results

In the simulant liquid experiments, the novel suction tips showed significantly reduced frequency of complete clogging and decreased time spent removing all fluid in comparison to the conventional suction tips (p<0.05). In the clinical trials, the novel suction tips exhibited significantly reduced frequency of complete clogging, shorter surgical duration, and reduced intraoperative surgical blood loss compared to the conventional suction tips (p<0.05). Surgeon satisfaction scores were higher for the novel tips than for the conventional tips (p<0.05).

Conclusions

Our surgeon-designed and -produced surgical suction tip utilizing 3D desktop printing technology was highly effective in resolving the problem of clogged suction tips during orthopedic surgery and yielded high surgeon satisfaction.

Feasibility of Modified Anterior Odontoid Screw Fixation: Analysis of a New Trajectory Using 3-Dimensional Simulation Software

BACKGROUND

Anterior odontoid screw fixation (AOSF) has been suggested as the optimal treatment for type II and some shallow type III odontoid fractures. However, only the classical surgical trajectory is available; no newer entry points or trajectories have been reported.

METHODS

We evaluated the anatomic feasibility of a new trajectory for AOSF using 3-dimensional (3D) screw insertion simulation software (Mimics). Computed tomography (CT) scans of patients (65 males and 59 females) with normal cervical structures were obtained consecutively, and the axes were reconstructed in 3 dimensions by Mimics software. Then simulated operations were performed using 2 new entry points below the superior articular process using bilateral screws of different diameters (group 1: 4 mm and 4 mm; group 2: 4 mm and 3.5 mm; group 3: 3.5 mm and 3.5 mm). The success rates and the required screw lengths were recorded and analyzed.

RESULTS

The success rates were 79.03% for group 1, 95.16% for group 2, and 98.39% for group 3. The success rates for groups 2 and 3 did not differ significantly, and both were significantly better than the rate for group 1. The success rate was much higher in males than in females in group 1, but the success rate was similar in males and females in the other 2 groups. Screw lengths did not differ significantly among the 3 groups, but an effect of sex was apparent.

CONCLUSIONS

Our modified trajectory is anatomically feasible for fixation of anterior odontoid fractures, but further anatomic experiments and clinical research are needed.

Anterior endoscopically assisted bone grafting for iatrogenic distraction of odontoid fracture after percutaneous anterior screw fixation: A case report

RATIONALE

The complication of iatrogenic distraction of odontoid fracture after anterior screw fixation has not been reported in the literature. We treated the patient with endoscopically assisted bone grafting with good results. The new technique was not reported in the management of odontoid fracture or nonunion before.

PATIENT CONCERNS

A 22-year-old man presented with neck pain after a motorcycle crash. The cervical spine radiograph and computed tomographic scan demonstrated the base of dens displaced 2 mm anteriorly.

DIAGNOSES

Radiographic images showed a type II odontoid fracture.

INTERVENTIONS

The patient was treated by percutaneous anterior screw fixation. The postoperative radiograph and CT demonstrated an iatrogenic distraction of the odontoid with a gap of 6 mm.The follow-up radiograph did not show any sign of bone union 1 month and a half later. A revision surgery was given by anterior endoscopically assisted bone grafting. The patient was encouraged to sit out of bed immediately after the surgery with the protection of a soft cervical collar for 3 months.

OUTCOMES

No complications such as neural structures or vascular injuries were found. Bone union was achieved at the 1-year follow-up CT scans. Physical examination showed a full range of motion in the neck.

LESSONS

We reported a case of iatrogenic odontoid distraction that was managed by anterior endoscopically assisted bone grafting. It is a technically feasible and minimally invasive procedure.

The Corona Dentis: Description of an Anatomic Variant with Technical Implications for Anterior Odontoid Screw Placement

BACKGROUND

Type 2 odontoid fractures are the most common cervical fractures among the elderly. Neurologic deficit is usually caused by myelopathy as a result of posterior dens migration. Direct anterior screw placement provides stabilization and can preserve C1-C2 movement. The presence of a bony excrescence on the anterior superior tip of the dens may lead to placement of a screw of incorrect length.

METHODS

Twenty C2 dry specimens were examined for the presence of a corona dentis, which is a bony excrescence in the coronal plane near the apex of the dens. When identified, measurements of the corona dentis were performed using calipers and a ruler. In addition, anteroposterior (AP) and lateral fluoroscopy was performed on all specimens found to have a corona dentis.

RESULTS

A corona dentis was found on 20% of our C2 specimens and had an average width of 9 mm and an average height of 4.5 mm. The average width of the dens did not vary as the normal tip of the dens transitioned into the coronae. In no specimen did the corona dentis seem to be composed of trabecular bone and it was seen as a superior projection of cortical bone on fluoroscopy. On fluoroscopy, the corona dentis could be identified on a true AP projection. In angulated AP views, fluoroscopic images overestimated the length of the corona dentis.

CONCLUSIONS

We describe a new entity termed the corona dentis because of its crownlike feature. It is a superior cortical bone protrusion and should be noted as a variant of the dens during anterior odontoid screw placement. Its propensity to increase the height of the dens markedly can lead to higher rates of neurologic deficits during type 2 odontoid fractures if not appreciated. A true AP view is critical for correct screw size placement.

Anterior retropharyngeal plate screw fixation with bilateral anterior transarticular screws for odontoid fractures ... a new comprehensive technique

INTRODUCTION

A certain group of odontoid fractures (Anderson and D' Alonzo Type-2) are usually offered surgical treatment. Common surgical option is an anterior odontoid screw. Some of the fractures are not suitable for anterior odontoid screw (anterior oblique, displaced distal fragments and those with atlantoaxial instability) and these are usually offered posterior transarticular screws (Magerl's) or posterior atlantoaxial screw rod/plate fixation (Goel-Harms technique). Posterior surgery involves atlantoaxial fixation with an indirect attempt to reduce and fuse the fracture . Posterior surgery has a risk of injury to the vertebral arteries, hemorrhage from the paravertebral venous plexus and the C2 root ganglion.

METHODS

A direct anterior submandibular retropharyangeal approach with open reduction and fixation (ORIF) using a customized variable screw placement (VSP) plate was used to realign and fix the fracture fragments in compression mode under direct vision. Twenty patients of type-II odontoid fractures (unsuitable for anterior odontoid screw) underwent an anterior retropharyngeal approach with anterior variable screw position (VSP) plate and screw fixation and eight amongst them, who had associated atlantoaxial instability underwent additional bilateral anterior transarticular screws.

RESULTS

All patients treated by this technique had 100% fracture site bone union without any implant failure. Longest follow-up has been for 3 years.

CONCLUSION

Anterior retropharyangeal approach allows direct fracture fragment realignment under vision with an opportunity to fix in compression mode using the VSP plate, which ensures early fusion across the type-II odontoid fracture. Any associated instability can be treated by additional bilateral anterior transarticular screws. The approach is simple and safe without any risk to the vertebral arteries and biomechanically appealing.

Biomechanical Assessment of Stabilization of Simulated Type II Odontoid Fracture with Case Study

STUDY DESIGN

Researchers created a proper type II dens fracture (DF) and quantified a novel current posterior fixation technique with spacers at C1-C2. A clinical case study supplements this biomechanical analysis.

PURPOSE

Researchers explored their hypothesis that spacers combined with posterior instrumentation (PI) reduce range of motion significantly, possibly leading to better fusion outcomes.

OVERVIEW OF LITERATURE

Literature shows that the atlantoaxial joint is unique in allowing segmental rotary motion, enabling head turning. With no intervertebral discs at these joints, multiple ligaments bind the axis to the skull base and to the atlas; an intact odontoid (dens) enhances stability. The most common traumatic injury at these strong ligaments is a type II odontoid fracture.

METHODS

Each of seven specimens (C0-C3) was tested on a custom-built six-degrees-of-freedom spine simulator with constructs of intact state, type II DF, C1-C2 PI, PI with joint capsulotomy (PIJC), PI with spacers (PIS) at C1-C2, and spacers alone (SA). A bending moment of 2.0 Nm (1.5°/sec) was applied in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). One-way analysis of variance with repeated measures was performed.

RESULTS

DF increased motion to 320%, 429%, and 120% versus intact (FE, LB, and AR, respectively). PI significantly reduced motion to 41%, 21%, and 8%. PIJC showed negligible changes from PI. PIS reduced motion to 16%, 14%, and 3%. SA decreased motion to 64%, 24%, and 54%. Reduced motion facilitated solid fusion in an 89-year-old female patient within 1 year.

CONCLUSIONS

Type II odontoid fractures can lead to acute or chronic instability. Current fixation techniques use C1-C2 PI or an anterior dens screw. Addition of spacers alongside PI led to increased biomechanical rigidity over intact motion and may offer an alternative to established surgical fixation techniques.

Passage of an Anterior Odontoid Screw through Gastrointestinal Tract

Purpose. Anterior screw fixation has become a popular surgical treatment method for instable odontoid fractures. Screw loosening and migration are a rare, severe complication following anterior odontoid fixation, which can lead to esophagus perforation and requires revision operation. Methods. We report a case of screw loosening and migration after anterior odontoid fixation, which perforated the esophagus and was excreted without complications in a 78-year-old male patient. Results. A ventral dislocated anterior screw perforated through the esophagus after eight years after implantation and was excreted through the gastrointestinal (GI) tract. At a 6-month follow-up after the event the patient was asymptomatic. Conclusion. Extrusion via the GI tract is not safe enough to be considered as a treatment option for loosened screws. Some improvements could be implemented to prevent such an incident. Furthermore, this case is a fine example that recent preoperative imaging is mandatory before revision surgery for screw loosening.

Deadly falls: operative versus nonoperative management of Type II odontoid process fracture in octogenarians

OBJECTIVE

Type II odontoid fracture is a common injury among elderly patients, particularly given their predisposition toward low-energy falls. Previous studies have demonstrated a survival advantage following early surgery among patients older than 65 years, yet octogenarians represent a medically distinct and rapidly growing population. The authors compared operative and nonoperative management in patients older than 79 years.

METHODS

A single-center prospectively maintained trauma database was reviewed using ICD-9 codes to identify octogenarians with C-2 cervical fractures between 1998 and 2014. Cervical CT images were independently reviewed by blinded neurosurgeons to confirm a Type II fracture pattern. Prospectively recorded outcomes included Glasgow Coma Scale (GCS) score, Abbreviated Injury Scale (AIS) score, Injury Severity Score (ISS), additional cervical fracture, and cord injury. Primary end points were mortality at 30 days and at 1 year. Statistical tests included the Student t-test, chi-square test, Fisher's exact test, Kaplan-Meier test, and Cox proportional hazard.

RESULTS

A total of 111 patients met inclusion criteria (94 nonoperative and 17 operative [15 posterior and 2 anterior]). Mortality data were available for 100% of patients. The mean age was 87 years (range 80–104 years). Additional cervical fracture, spinal cord injury, GCS score, AIS score, and ISS were not associated with either management strategy at the time of presentation. The mean time to death or last follow-up was 22 months (range 0–129 months) and was nonsignificant between operative and nonoperative groups (p = 0.3). Overall mortality was 13% in-hospital, 26% at 30 days, and 41% at 1 year. Nonoperative and operative mortality rates were not significant at any time point (12% vs 18%, p = 0.5 [in-hospital]; 27% vs 24%, p = 0.8 [30-day]; and 41% vs 41%, p = 1.0 [1-year]). Kaplan-Meier analysis did not demonstrate a survival advantage for either management strategy. Spinal cord injury, GCS score, AIS score, and ISS were significantly associated with 30-day and 1-year mortality; however, Cox modeling was not significant for any variable. Additional cervical fracture was not associated with increased mortality. The rate of nonhome disposition was not significant between the groups.

CONCLUSIONS

Type II odontoid fracture is associated with high morbidity among octogenarians, with 41% 1-year mortality independent of intervention—a dramatic decrease from actuarial survival rates for all 80-, 90-, and 100-year-old Americans. Poor outcome is associated with spinal cord injury, GCS score, AIS score, and ISS.

Conservative Management of Odontoid Peg Fractures, long term follow up

OBJECTIVE

The aim of the study was to look at the long-term effects of conservative management of odontoid peg fractures.

METHODS

We reviewed 48 consecutive patients with type II (32) and 16 type III, odontoid peg fractures. The clinical & radiological outcomes were assessed over an average period of follow up of 8 years. Union rate was determined and we discussed several factors that may affect it. Patients were treated conservatively with an average period of bed rest of 4 weeks followed by bracing for an average of 9 weeks.

RESULTS

Bony union was established in 25 of 32 (78%) type II fractures. Of 7 cases of no bony union 4 were stable probably with fibrous union. 3 remained unstable. In 13 of 16(83%) type III fractures bony union was established. 2 of the 3 with no bony union were considered stable.

CONCLUSION

Osseous non-union was higher in patients with displacement of >5 mm, but there is no correlation between union and age, gender or angulation of the fracture in both types.

Anterior single odontoid screw placement for type II odontoid fractures: our modified surgical technique and initial results in a cohort study of 15 patients

Objective: Anterior odontoid screw fixation for type II odontoid fracture is the ideal management option. However in the context of unavailability of an O-arm or neuro-navigation and poor images from the available C-arm may be an obstacle to ideal trajectory and placement of the odontoid screw. We herein detail  our surgical technique so as to ensure a correct trajectory and subsequent good fusion in Type II odontoid fractures. This may be advantageous  in clinical set ups lacking state of the art facilities. 

Methods and Results: In this cohort study we included 15 consecutive patients who underwent anterior odontoid screw placement. We routinely dissect the longus colli to completely visualize the entire width of C3 body. We then perform a median C2-C3 disectomy followed by creating a gutter in the superior end of C3 body. We then guide the Kirchsner (K) wire purchasing adequate anterior cortex of C2. Rest of the procedure follows the similar steps as described for odontoid screw placement.

We achieved 100% correct trajectory and screw placement in our study. There were no instances of screw break out, pull out or nonunion. There was one patient mortality following myocardial infarction in our study.

Conclusion: Preoperative imaging details, proper patient positioning, meticulous dissection, thorough anatomical knowledge and few added surgical nuances are the cornerstones in ideal odontoid screw placement. This may be pivotal in managing  patients in developing nations having rudimentary neurosurgical set up.