Two-screw osteosynthesis is biomechanically superior to single-screw osteosynthesis for type II odontoid fractures.

The data on the use of a one- or two-screw technique (1S, 2S) for ventral osteosynthesis of type II dens fractures are contradictory. The aim was to design an apparatus to mimic the physiological conditions and test stability with 1S, 2S, and a headless compression screw (HCS) for osteosynthesis of artificially created type II odontoid fractures. The apparatus was mounted on a Zwick materials testing machine. A total of 18 C1-2 specimens were stratified into three groups (1S, 2S, HCS). Odontoid fractures were artificially created, and osteosynthesis was performed. Each specimen was tested at loads increasing from 1 to 40 N. Screw loosening was observed visually, by fatigue data, and by a camera tracking system. Analysis of the Zwick data and the camera data revealed a significant higher stability after 2S compared to 1S and HCS treatment (Zwick data: p = 0.021, camera data: p < 0.001), while visible screw loosening showed a superiority of the 2S only over HCS (p = 0.038). The developed apparatus allowed the dynamic study of the atlantoaxial joint with a high approximation to physiological conditions. The results demonstrated superiority of the 2S over the 1S and HCS in biomechanical stability in the treatment of type II odontoid fractures.

Surgical versus conservative treatment for odontoid fractures in older people: an international prospective comparative study.

BACKGROUND: The optimal treatment for odontoid fractures in older people remains debated. Odontoid fractures are increasingly relevant to clinical practice due to ageing of the population. METHODS: An international prospective comparative study was conducted in fifteen European centres, involving patients aged ≥55 years with type II/III odontoid fractures. The surgeon and patient jointly decided on the applied treatment. Surgical and conservative treatments were compared. Primary outcomes were Neck Disability Index (NDI) improvement, fracture union and stability at 52 weeks. Secondary outcomes were Visual Analogue Scale neck pain, Likert patient-perceived recovery and EuroQol-5D-3L at 52 weeks. Subgroup analyses considered age, type II and displaced fractures. Multivariable regression analyses adjusted for age, gender and fracture characteristics. RESULTS: The study included 276 patients, of which 144 (52%) were treated surgically and 132 (48%) conservatively (mean (SD) age 77.3 (9.1) vs. 76.6 (9.7), P = 0.56). NDI improvement was largely similar between surgical and conservative treatments (mean (SE) -11 (2.4) vs. -14 (1.8), P = 0.08), as were union (86% vs. 78%, aOR 2.3, 95% CI 0.97-5.7) and stability (99% vs. 98%, aOR NA). NDI improvement did not differ between patients with union and persistent non-union (mean (SE) -13 (2.0) vs. -12 (2.8), P = 0.78). There was no difference for any of the secondary outcomes or subgroups. CONCLUSIONS: Clinical outcome and fracture healing at 52 weeks were similar between treatments. Clinical outcome and fracture union were not associated. Treatments should prioritize favourable clinical over radiological outcomes.

[3D printing navigation template assisted pedicle screw placement for the treatment of typeâ ¡old odontoid fractures].

OBJECTIVE: To compare the safety and clinical efficacy of freehand and 3D printing navigation template assisted screw placement in patients with old odontoid fractures of typeⅡ. METHODS: Total of 38 patients with old odontoid fractures of typeⅡwere treated from November 2018 to December 2022, all of which presented as chronic neck pain. According to the different methods of screw insertion into the pedicle, the patients were divided into a navigation template group and a freehand group. In the navigation template group, there were 17 patients including 9 males and 8 females with an average age of (51.30±13.20) years old, disease duration was (22.18±7.59) months. In the freehand group, there 21 patients including 7 males and 14 females with an average age of (49.46±11.92) years old, disease duration was (19.52±9.17) months. The intraoperative blood loss, operation time, and postoperative drainage output were recorded and compared between two groups. The accuracy of screw placement was evaluated by CT scan. Before operation and 1 year after operation, cervical pain was assessed by visual analogue scale(VAS), neurological changes were evaluated by the Japanese Orthopaedic Association (JOA) score, and the degree of spinal cord injury was assessed by the American Spinal Injury Association (ASIA) injury scale. RESULTS: All patients were followed up for (25.31±1.21) months. The operation time of template group (112.00±20.48) min had significantly shorter than that of the freehand group(124.29±15.24) min(P<0.05), while there were no significant differences between two groups in terms of intraoperative blood loss, postoperative drainage, and hospital stay(P>0.05). At 1 year after operation, in template group and freehand group, the VAS [(2.88±0.86), (2.90±0.83)] and JOA [(14.94±1.82), (14.62±2.19)] improved with preoperative [VAS(4.71±0.92), (4.86±0.79) and JOA (12.18±2.30), (11.95±2.31)](P<0.05), with no significant difference between two groups (P>0.05). No significant improvement was observed in ASIA grading in either group at 1 year after operation(P>0.05), and there was no significant difference between two groups(P>0.05). The template group had significantly better accuracy of screw placement in the pedicle of the axis than the freehand group (P<0.05), while no significant difference was observed between two groups in the accuracy of screw placement in the pedicle of the atlas (P>0.05). CONCLUSION: In the treatment of typeⅡold odontoid fractures with posterior pedicle screw fixation, 3D printing navigation template screw placement can significantly shorten the operation time, achieve similar clinical efficacy as free-hand screw placement, and significantly improve the accuracy of screw placement in the pedicle of the axis.

The epidemiology of odontoid fractures: a study from the Swedish fracture register.

PURPOSE: The objective of this study is to characterize the occurrence of odontoid fractures within a Swedish population. METHODS: Prospective data of adults diagnosed with an odontoid fracture between 2015 and 2021 were retrieved from the Swedish Fracture Register (SFR). Epidemiologic data including age, sex, injury mechanism, injury type, fracture type (Anderson and D'Alonzo classification), neurological status and treatment type were requested from the SFR. Data pertinent to osteoporosis was retrieved from the Swedish National Patient Register. RESULTS: A total of 1,154 odontoid fractures were identified, of which 30 were type I fractures, 583 type II fractures, and 541 type III fractures. The mean (Standard Deviation [SD]) age was 77.2 (13.8) years. The prevalence of osteoporosis and neurological deficits did not differ between the fracture types. The majority of patients were treated non-surgically (81%). Male sex and patient age 18-30 years were commonly associated with a high-injury mechanism, especially motor vehicle accidents. In the type II fracture group, significantly more patients had fallen from standing height or less than in the type III group (66% vs. 58%, p = 0.01) while in contrast, motor vehicle accidents were more common in the type III fracture group (12% vs. type II: 8%, p = 0.04). CONCLUSION: Based on the SFR, the typical odontoid fracture patient is older and suffers a type II fracture. Most injuries were caused by low-energy trauma although in younger patients and males, they were associated with motor vehicle accidents. Across the patient population, odontoid fractures were usually treated non-surgically.

Augmented Reality in Spine Surgery: A Case Study of Atlantoaxial Instrumentation in Os Odontoideum.

Despite advancement in surgical innovation, C1-C2 fixation remains challenging due to risks of screw malposition and vertebral artery (VA) injuries. Traditional image-based navigation, while useful, often demands that surgeons frequently shift their attention to external monitors, potentially causing distractions. In this article, we introduce a microscope-based augmented reality (AR) navigation system that projects both anatomical information and real-time navigation images directly onto the surgical field. In the present case report, we discuss a 37-year-old female who suffered from os odontoideum with C1-C2 subluxation. Employing AR-assisted navigation, the patient underwent the successful posterior instrumentation of C1-C2. The integrated AR system offers direct visualization, potentially minimizing surgical distractions. In our opinion, as AR technology advances, its adoption in surgical practices and education is anticipated to expand.

Posterior atlantoaxial fixation of osteoporotic odontoid fracture: biomechanical analysis of the Magerl versus harms techniques in a cadaver model.

BACKGROUND CONTEXT: Odontoid fractures are among the most common cervical spine fractures in the elderly and are associated with increased morbidity and mortality. Clinical evidence suggests improved survival and quality of life after operative intervention compared to nonoperative treatment. PURPOSE: This study seeks to examine the stability of an osteoporotic Type II odontoid fracture following posterior atlantoaxial fixation with either the Magerl transarticular fixation technique or the Harms C1 lateral mass screws C2 pedicle screw rod fixation. STUDY DESIGN: Biomechanical cadaveric study. METHODS: Eighteen cadaveric specimens extending from the cephalus to C7 were used in this study. Reflective marker arrays were attached to C1 and C2 and a single marker on the dens to measure movement of each during loading with C2-C3 and occiput-C1 being allowed to move freely. A biomechanical testing protocol imparted moments in flexion-extension, axial rotation, and lateral bending while a motion capture system recorded the motions of C1, C2, and the dens. The spines were instrumented with either the Harms fixation (n=9) or Magerl fixation (n=9) techniques, and a simulated Type II odontoid fracture was created. Motions of each instrumented spine were recorded for all moments, and then again after the instrumentation was removed to model the injured, noninstrumented state. RESULTS: Both Harms and Magerl posterior C1-C2 fixation allowed for C1, C2, and the dens to move as a relative unit. Without fixation the dens motion was coupled with C1. No significant differences were found in X, Y, Z translation motion of the dens, C1 or C2 during neutral zone motions between the Magerl and Harms fixation techniques. There were no significant differences found in Euler angle motion between the two techniques in either flexion-extension, axial rotation, or lateral bending motion. CONCLUSIONS: Our findings suggest that both Harms and Magerl fixation can significantly reduce dens motion in Type II odontoid fractures in an osteoporotic cadaveric bone model. CLINICAL SIGNIFICANCE: Both Harms and Magerl posterior atlantoaxial fixation techniques allowed for C1, C2, and the dens to move as a relative unit following odontoid fracture, establishing more anatomic stability to the upper cervical spine.

Unilateral Biplanar Screw-Rod Fixation Technique for the Treatment of Odontoid Fractures in Patients with Atlantoaxial Bone or Vascular Abnormalities.

OBJETIVE: This study aims to introduce the unilateral biplanar screw-rod fixation (UBSF) technique (a hybrid fixation technique: 2 sets of atlantoaxial screws were placed on the same side), which serves as a salvage method for traditional posterior atlantoaxial fixation. To summarize the indications of this technique and to assess its safety, feasibility, and clinical effectiveness in the treatment of odontoid fractures. METHODS: Patients with odontoid fractures were enrolled according to special criteria. Surgical duration and intraoperative blood loss were documented. Patients were followed up for a minimum of 12 months. X-ray and computerized tomography scans were conducted and reviewed at 1 day, and patients were asked to return for computerized tomography reviews at 3, 6, 9, and 12 months after surgery until fracture union. Recorded and compared the Neck Visual Analog Scale and Neck Disability Index presurgery and at 1 week and 12 months postsurgery. RESULTS: Between January 2016 and December 2022, our study enrolled 7 patients who were diagnosed with odontoid fractures accompanied by atlantoaxial bone or vascular abnormalities. All 7 patients underwent successful UBSF surgery, and no neurovascular injuries were recorded during surgery. Fracture union was observed in all patients, and the Neck Visual Analog Scale and Neck Disability Index scores improved significantly at 1 week and 12 months postoperative (P < 0.01). CONCLUSIONS: The UBSF technique has been demonstrated to be safe, feasible, and effective in treating odontoid fractures. In cases where the atlantoaxial bone or vascular structure exhibits abnormalities, it can function as a supplementary or alternative approach to the conventional posterior C1-2 fixation.

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

BACKGROUND: Combined triple atlas (C1)-axis (C2) fixation has been described in previous literature as a safe, effective, and minimally invasive procedure for complex atlas and odontoid fractures that allows for a greater range of motion compared with posterior approaches and atlanto-occipital fusion. However, it is rarely performed due to the occipital-cervical diastasis resulting from often-fractured C1 joint masses. No evidence-based consensus has been reached regarding the treatment of complex atlantoaxial fractures, and the choice of surgical strategy is based only on clinical experience. METHODS: We report the combined triple C1-C2 fixation technique with manual reduction of the joint masses during patient positioning on the operating table, which allowed for effective stabilization during a single surgical session. We describe our experience in the management of a 75-year-old patient presenting with an acute complex type II fracture of C1, which also involved 1 lateral mass, combined with a type II odontoid fracture and occipital-cervical diastasis. RESULTS: We provide a step-by-step guide for combined triple C1-C2 anterior fixation with manual fracture reduction and describe the clinical case of an acute complex type II fracture of C1, which also involved 1 lateral mass, combined with a type II odontoid fracture and occipital-cervical diastasis. CONCLUSIONS: Combined triple C1-C2 fixation represents a safe and efficient minimally invasive anterior approach for complex type II fractures of C1 with type II odontoid fractures. Manual reduction of the joint masses during patient positioning allows for effective stabilization in a single surgical session.

Surgical management of spinal pathologies in the octogenarian: a narrative review.

Optimal management paradigms of spinal pathologies in the octogenarian population are controversial given the higher incidence of comorbidities with concern for poor prognosis and fear of increased complications associated with surgical management. In this narrative review, we aim to detail the complex clinical considerations when approaching odontoid screw fixation/instrumented fusion, spinal decompression, and spinal fusion in the octogenarian. Literature review was conducted via Google Scholar and PubMed databases, with literature selected based on statistical power and clinical relevance to the following pathologies/surgical techniques: odontoid fracture, surgical decompression, and surgical fusion in the octogenarian. The aforementioned pathologies were selected based on prevalence in the advanced-age population in which surgical screening techniques and management remain nonuniform. Preoperative evaluation of the octogenarian patient increasingly includes frailty, sarcopenia, and osteopenia/osteoporosis assessments. In cases of odontoid fracture, conservative management appears to provide beneficial clinical outcomes with lower rates of complication compared to surgery; however, rates of radiographic odontoid fusion are far lower in conservatively managed patients. Regarding surgical decompression and fusion, the presence of comorbidities may be more predictive of outcome rather than age status, with the advent of minimally invasive techniques providing safety and efficacy in the surgical management of this age cohort. Age status may be less pertinent than previously thought in the decision to pursue spinal surgery for odontoid fracture, spinal decompression, or spinal fusion; however, each of these procedures has respective risks and benefits that must be considered within the context of each patient's comorbidity profile.

Evidence and Controversies in Geriatric Odontoid Fracture Management.

Geriatric odontoid fractures are some of the most common spine injuries in our aging population, and their prevalence is only continuing to increase. Despite several investigational studies, treatment remains controversial and there is limited conclusive evidence regarding the management of odontoid fractures. These injuries typically occur in medically complex and frail geriatric patients with poor bone quality, making their treatment particularly challenging. In this article, we review the evidence for conservative management as well as surgical intervention and discuss various treatment strategies. Given the high morbidity and mortality associated with odontoid fractures in the elderly, thoughtful consideration and an emphasis on patient-centered goals of treatment are critical to maximize function in this vulnerable population.

Development of a Predictive Model for Persistent Instability Following Conservative Management of Type II Odontoid Fractures.

BACKGROUND: Odontoid fractures are common cervical spine fractures; however, significant controversy exists regarding their treatment. Risk factors for failure of conservative therapy have been identified, although no predictive risk score has been developed to aid in decision-making. METHODS: A retrospective review was conducted of all patients evaluated at a level 1 trauma center. Patients identified with type II odontoid fractures as classified by the D'Alonzo Classification system who were treated with external orthosis were included in analysis. Patients were considered to have failed conservative therapy if they were offered surgical intervention. A machine learning method (Risk-SLIM) was then utilized to create a risk stratification score based on risk factors to identify patients at high risk for requiring surgical intervention due to persistent instability. RESULTS: A total of 138 patients were identified as presenting with type II odontoid fractures that were treated conservatively; 38 patients were offered surgery for persistent instability. The Odontoid Fracture Predictive Model (OFPM) was created using a machine learning algorithm with a 5-fold cross validation area under the curve of 0.7389 (95% CI: 0.671 to 0.808). Predictive factors were found to include fracture displacement, displacement greater than 5 mm, comminution at the fracture base, and history of smoking. The probability of persistent instability was <5% with a score of 0 and 88% with a score of 5. CONCLUSIONS: The OFPM model is a unique, quick, and accurate tool to assist in clinical decision-making in patients with type II odontoid fractures. External validation is necessary to evaluate the validity of these findings.

Operative Management Improves Near-term Survival of Patients With Odontoid Type II Fractures: A Propensity-matched National Registry Analysis.

STUDY DESIGN: National Trauma Data Bank (NTDB) review and propensity-matched analysis. OBJECTIVE: To evaluate differences in clinical outcomes by operative management. SUMMARY OF BACKGROUND DATA: Odontoid type II fractures are the most prevalent cervical fracture. Operative intervention on these fractures is frequently debated; surgical risks are compounded by clinical severity, patient age, and comorbidities. METHODS: This registry review included index admissions for odontoid type II fractures [International Classification of Diseases (ICD)-10 codes beginning with S12.11] from 1/1/2017 to 1/1/2020; patients who died in the emergency department (ED) were excluded. Propensity score techniques were used to match patients 1:1 by surgical management, using a caliper distance of 0.05, after matching on the following covariates that differed significantly between surgical and nonsurgical patients: age, sex, race, cause of injury, transfer status, injury severity score, ED Glasgow coma score, ED systolic blood pressure, presence of transverse ligamentous injury, cervical dislocation, and 8 comorbidities. The following outcomes were analyzed with McNemar tests and Wilcoxon signed-rank tests: near-term survival (discharged from the hospital to locations other than morgue or hospice), intensive care unit (ICU) admission, hospital complications, median hospital length of stay (LOS), and median ICU LOS. RESULTS: There were 16,607 patients, 2916 (17.6%) were operatively managed and 13,691 were nonoperatively managed. Before matching, survival was greater for patients managed operatively compared with nonoperatively (95.0% vs. 88.2%). The matched population consisted of 5334 patients: 2667 patients in the operative group (91.5% of this population) and 2667 well-matched patients in the nonoperative group. After matching, there was a survival benefit for patients who were operatively managed compared with nonoperative management (94.8% vs. 91.4% P <0.001). However, operative management was associated with greater development of complications, ICU admission, and longer hospital and ICU LOS. CONCLUSION: Compared with nonoperative management, operative management demonstrated a significant near-term survival benefit for patients with odontoid type II fractures in select patients. LEVEL OF EVIDENCE: III.

Type II odontoid fractures in the elderly presenting to the emergency department: an assessment of factors affecting in-hospital mortality and discharge to skilled nursing facilities.

BACKGROUND CONTEXT: Type II odontoid fractures (OF) are among the most common cervical spine injuries in the geriatric population. However, there is a paucity of literature regarding their epidemiology. Additionally, the optimal management of these injuries remains controversial, and no study has evaluated the short-term outcomes of geriatric patients presenting to emergency departments (ED). PURPOSE: This study aims to document the epidemiology of geriatric patients presenting to EDs with type II OFs and determine whether surgical management was associated with early adverse outcomes such as in-hospital mortality and discharge to skilled nursing facilities (SNF). STUDY DESIGN: This is a retrospective cohort study. PATIENT SAMPLE: Data was used from the 2016-2020 Nationwide Emergency Department Sample. Patient encounters corresponding to type II OFs were identified. Patients younger than 65 at the time of presentation to the ED and those with concomitant spinal pathology were excluded. OUTCOME MEASURES: The association between the surgical management of geriatric type II OFs and outcomes such as in-hospital mortality and discharge to SNFs. METHODS: Patient, fracture, and surgical management characteristics were recorded. A propensity score matched cohort was constructed to reduce differences in age, comorbidities, and injury severity between patients undergoing operative and nonoperative management. Additionally, to develop a positive control for the analysis of geriatric patients with type II OFs and no other concomitant spinal pathology, a cohort of patients that had been excluded due to the presence of a concomitant spinal cord injury (SCI) was also constructed. Multivariate regressions were then performed on both the matched and unmatched cohorts to ascertain the associations between surgical treatment and in-hospital mortality, inpatient length of stay, encounter charges, and discharge to SNFs. RESULTS: A total of 11,325 encounters were included. The mean total charge per encounter was $60,221. 634 (5.6%) patients passed away during their encounters. In total, 1,005 (8.9%) patients were managed surgically. Surgical management of type II OFs was associated with a 316% increase in visit charge (95% CI: 291%-341%, p<.001), increased inpatient length of stay (IRR: 2.87, 95% CI: 2.62-3.12, p<.001), and increased likelihood of discharge to SNFs (OR=2.62, 95% CI: 2.26-3.05, p<.001), but decreased in-hospital mortality (OR=0.32, CI: 0.21-0.45, p<.001). The propensity score matched cohort consisted of 2,010 patients, matching each of the 1,005 that underwent surgery to 1,005 that did not. These cohorts were well balanced across age (78.24 vs 77.91 years), Elixhauser Comorbidity Index (3.68 vs 3.71), and Injury Severity Score (30.15 vs 28.93). This matching did not meaningfully alter the associations determined between surgical management and in-hospital mortality (OR=0.34, CI=0.21-0.55, p<.001) or SNF discharge (OR=2.59, CI=2.13-3.16, p<.001). Lastly, the positive control cohort of patients with concurrent SCI had higher rates of SNF discharge (50.0% vs 42.6%, p<.001), surgical management (32.3% vs 9.7%, p<.001), and in-hospital mortality (28.9% vs 5.6%, p<.001). CONCLUSIONS: This study lends insight into the epidemiology of geriatric type II OFs and quantifies risk factors influencing adverse outcomes. Patient informed consent should include a discussion of the protective association between definitive surgical management and in-hospital mortality against potential operative morbidity, increased lengths of hospital stay, and increased likelihood of discharge to SNFs. This information may impact patient treatment selection and decision making.

Odontoid fractures above C2 to pelvis posterior instrumented fusions: a single center's 11-year experience.

PURPOSE: To define the prevalence, characteristics, and treatment approach for proximal junction failure secondary to odontoid fractures in patients with prior C2-pelvis posterior instrumented fusions (PSF). METHODS: A single institution's database was queried for multi-level fusions (6+ levels), including a cervical component. Posterior instrumentation from C2-pelvis and minimum 6-month follow-up was inclusion criteria. Patients who sustained dens fractures were identified; each fracture was subdivided based on Anderson & D'Alonzo and Grauer's classifications. Comparisons between the groups were performed using Chi-square and T tests. RESULTS: 80 patients (71.3% female; average age 68.1 ± 8.1 years; 45.0% osteoporosis) were included. Average follow-up was 59.8 ± 42.7 months. Six patients (7.5%) suffered an odontoid fracture post-operatively. Cause of fracture in all patients was a mechanical fall. Average time to fracture was 23 ± 23.1 months. Average follow-up after initiation of fracture management was 5.84 ± 4 years (minimum 1 year). Three patients sustained type IIA fractures one of which had a concomitant unilateral C2 pars fracture. Three patients sustained comminuted type III fractures with concomitant unilateral C2 pars fractures. Initial treatment included operative care in 2 patients, and an attempt at non-operative care in 4. Non-operative care failed in 75% of patients who ultimately required revision with proximal extension. All patients with a concomitant pars fracture had failure of non-operative care. Patients with an intact pars were more stable, but 50% required revision for pain. CONCLUSIONS: In this 11-year experience at a single institution, the prevalence of odontoid fractures above a C2-pelvis PSF was 7.5%. Fracture morphology varied, but 50% were complex, comminuted C2 body fractures with concomitant pars fractures. While nonoperative management may be suitable for type II fractures with simple patterns, more complex and unstable fractures likely benefit from upfront surgical intervention to prevent fracture displacement and neural compression. As all fractures occurred secondary to a mechanical fall, inpatient and community measures aimed to minimize risk and prevent mechanical falls would be beneficial in this high-risk group.

Biomechanical comparison of two different compression screws for the treatment of odontoid fractures in human dens axis specimen.

BACKGROUND: Lag screw osteosynthesis for odontoid fractures has a high rate of pseudoarthrosis, especially in elderly patients. Besides biomechanical properties of the different screw types, insufficient fragment compression or unnoticed screw stripping may be the main causing factors for this adverse event. The aim of the study was to compare two screws in clinical use with different design principles in terms of compression force and stability against screw stripping. METHODS: Twelve human cadaveric C2 vertebral bodies were considered. Bone density was determined. The specimens were matched according to bone density and randomly assigned to two experimental groups. An odontoid fracture was induced, which were fixed either with a 3.5 mm standard compression screw or with a 5 mm sleeve nut screw. Both screws are certified for the treatment of odontoid fractures. The bone samples were fixed in a measuring device. The screwdriver was driven mechanically. The tests were analyzed for peak interfragmentary compression and screw-in torque with a frequency of 20 Hz. FINDINGS: The maximum fragment compression was significantly higher with screw with sleeve nut at 346.13(SD ±72.35) N compared with classic compression screw at 162.68(SD ±114.13) N (p = 0.025). Screw stripping occurred significantly earlier in classic compression screw at 255.5(SD ±192.0)° rotation after reaching maximum compression than in screw with sleeve nut at 1005.2(SD ±341.1)° (p = 0.0039). INTERPRETATION: Screw with sleeve nut achieves greater fragment compression and is more robust to screw stripping compared to classic compression screw. Whether the better biomechanical properties lead to a reduction of pseudoarthrosis has to be proven in clinical studies.

Feasibility of Two-Screw Anterior Fixation for Odontoid Fractures in a Chinese Population: A Morphometric Study Based on Computed Tomography.

Background: To evaluate the feasibility of treating odontoid fractures in the Chinese population with two cortical screws based on computed tomography (CT) scans and describe a new measurement strategy to guide screw insertion in treating these fractures. Methods: A retrospective review of cervical computed tomographic scans of 128 patients (aged 18-76 years; men, 55 [43.0%]) was performed. The minimum external transverse diameter (METD), minimum external anteroposterior diameter (MEAD), maximum screw length (MSL), and screw projection back angle (SPBA) of the odontoid process were measured on coronal and sagittal CT images. Results: The mean values of METD and MEAD were 10.0 ± 1.1 mm and 12.0 ± 1.0 mm, respectively, in men and 9.2 ± 1.0 mm and 11.0 ± 1.0 mm, respectively, in women. Both measurements were significantly higher in men (p < 0.001). In total, 87 individuals (68%) had METD > 9.0 mm that could accommodate two 3.5-mm cortical screws. The mean MSL value and SPBA range were 34.4 ± 2.9 mm and 13.5°-24.2°, respectively, with no statistically significant difference between men and women. Conclusions: The insertion of two 3.5-mm cortical screws was possible for anterior fixation of odontoid fractures in 87 patients (68%) in our study, and there was a statistically significant difference between men and women.

Outcomes of Odontoid Process Fracture Surgery.

BACKGROUND: Odontoid fractures are found in two age groups. In younger patients, they occur following traffic accidents, falls from a height and during sports. In older patients with poor bone quality, they are usually caused by falls from one's own height. Most fractures are stable and do not require surgical treatment. Unstable, severely displaced fractures with neurological deficits require surgical treatment. The aim of the study was to evaluate the surgical and functional outcomes of treatment of odontoid fractures with a cannulated screw. MATERIALS AND METHODS: The study enrolled 20 patients that underwent surgery in the years 2020-2022. The patients were divided into two groups: below 60 (group A) and over 60 years of age (group B). Patients were assessed at one day pre-op, one day post-op, 6 weeks following surgery and 3 months following surgery. Imaging studies were performed to assess the angulation and degree of displacement of bone fragments. After the fracture was surgically fixed with a cannulated screw, bone union and the stability of fracture fixation were assessed. Preoperative and postoperative pain intensity as per a VAS, functional status assessed with the NDI questionnaire, quality of life (EQ-VAS) and neurological status (ASIA scale) were compared. RESULTS: Good functional and surgical results were obtained in both groups of patients. Performance and quality of life improved, while pain intensity decreased in all patients. In 3 patients with post-traumatic paresis, the dysfunctions gradually subsided. No general medical or perioperative complications were observed. Bone union of the fracture was achieved in 40% of patients in group B and in 80% in group A. Achieving union did not determine the functional status of patients. On functional radiographs, all places of fixation were stable. CONCLUSIONS: 1. Odontoid fracture fixation with a single cannulated screw is a safe method of treatment. It provided a high union rate and good stability of the fracture. 2. Fracture non-union was noted more often in the group of older patients, but it did not negatively impact quality of life and performance.

Odontoid fracture in geriatric patients - analysis of complications and outcome following conservative treatment vs. ventral and dorsal surgery.

BACKGROUND: Different treatment options are discussed for geriatric odontoid fracture. The aim of this study was to compare the treatment options for geriatric odontoid fractures. METHODS: Included were patients with the following criteria: age ≥ 65 years, identification of seniors at risk (ISAR score ≥ 2), and odontoid fracture type A/B according to Eysel and Roosen. Three groups were compared: conservative treatment, surgical therapy with ventral screw osteosynthesis or dorsal instrumentation. At a follow-up examination, the range of motion and the trabecular bone fracture healing rate were evaluated. Furthermore, demographic patient data, neurological status, length of stay at the hospital and at the intensive care unit (ICU) as well as the duration of surgery and occurring complications were analyzed. RESULTS: A total of 72 patients were included and 43 patients could be re-examined (range: 2.7 ± 2.1 months). Patients with dorsal instrumentation had a better rotation. Other directions of motion were not significantly different. The trabecular bone fracture healing rate was 78.6%. The patients with dorsal instrumentation were hospitalized significantly longer; however, their duration at the ICU was shortest. There was no significant difference in complications. CONCLUSION: Geriatric patients with odontoid fracture require individual treatment planning. Dorsal instrumentation may offer some advantages.