Analysis of the Literature on Cervical Spine Fractures in Ankylosing Spinal Disorders

Cervical spine fracture in diffuse idiopathic skeletal hyperostosis: A bibliometric analysis

Objective

The study aimed to assess and investigate cervical spine fracture in diffuse idiopathic skeletal hyperostosis and to identify research trends in cervical spine fracture in diffuse idiopathic skeletal hyperostosis in countries around the world using bibliometric analysis.

Method

We examined bibliometric data obtained from the Scopus database collection for the periods 1 January 2000 and 1 January 2022. Authors, institutions, nations, publications, keywords, and references were noted and analyzed. The total number of research articles published on the subject of diffuse idiopathic skeletal hyperostosis was used to calculate the amount of research on that subject undertaken in the study period. A sample of the publication data collected from the Scopus database was then analyzed using the Bibliometric program and used to develop a relationship chart using the Bibliometrix and VOSviewer programs.

Results

The number of citations was assumed to be a qualitative measure of the publication. We estimated the impact of the research using several metrics, including the H-index, in the bibliometric analysis of authors, geographic areas, institutes, and references. A total of 52 studies related to cervical spine fractures in diffuse idiopathic skeletal hyperostosis were identified. Only 5.12% of those studies were cited in other publications, for a total of 1410 citations in publications by 342 authors, of whom only two authors had published a single study. Co-authorships occurred at 7.273%. Diseases common in elderly males were often studied retrospectively, and "Diffuse Idiopathic Skeletal Hyperostosis" was a frequently mentioned keyword.

Conclusion

The findings of this study provide insights into authors, institutions, key publications, and research trends related to diffuse idiopathic skeletal hyperostosis and can potentially serve as a guide for further studies in the field. The bibliometric analysis of cervical spine fractures in patients with diffuse idiopathic skeletal hyperostosis highlights important contributors, influential papers, geographical trends, and study characteristics in this area of research.

Decreasing incidence of cervical spine fractures in patients with ankylosing spondylitis: a population-based study in Southeast Norway

BACKGROUND CONTEXT

Individuals diagnosed with ankylosing spondylitis (AS) face an increased risk of spine fractures, specifically cervical spine fractures (CS-Fxs). In the past two decades, biological disease-modifying antirheumatic drugs (bDMARDs) have provided considerable relief from pain and an enhanced sense of wellbeing for a large segment of AS patients. Despite these improvements, it remains unclear whether extended use of bDMARDs can indeed reduce the risk of spine fractures.

PURPOSE

In this study, we aimed to investigate the evolving patterns and epidemiology of traumatic CS-Fxs in both AS and non-AS populations. We hypothesized that the risk of CS-Fxs among AS patients would show a decreasing trend over time, while the risk among non-AS patients would remain constant.

STUDY DESIGN/SETTING

Retrospective cohort study based on a prospective database.

PATIENT SAMPLE

A total of 3,598 consecutive patients with CS-Fxs were treated at Oslo University Hospital over an 8-year period.

OUTCOME MEASURES

CS-Fxs in AS patients were contrasted with non-AS-related CS-Fxs in terms of temporal trends, age, sex, injury mechanism, associated cervical spinal cord injury (cSCI), need for surgical fixation, and 30-day mortality.

METHODS

Data regarding all CS-Fxs diagnosed between 2015 and 2022 were extracted from the Southeast Norway population-based quality control database for traumatic CS-Fxs. Categorical data were summarized using frequencies, and continuous data were summarized using medians. The Wilcoxon rank-sum test was used to compare continuous variables, and the chi-squared test and Fischer exact test were used to compare categorical variables. To investigate the trend in the incidence of fractures, two different Poisson models were fitted with the number of non-AS and AS fractures as dependent variables and the year as the explanatory variable.

RESULTS

Over an eight-year period, we registered 3,622 CS-Fxs in 3598 patients, with AS patients accounting for 125 of these fractures. Relative to their non-AS counterparts, AS patients presented a 9-fold and 8-fold higher risk of initial and subsequent CS-Fxs, respectively. We observed a declining trend in AS-related CS-Fxs with an annual linear decrease of 8.4% (p=.026), whereas non-AS-related CS-Fxs showed an annual linear increase of 3.7% (p<.001). AS patients sustaining CS-Fxs were typically older (median age 70 vs. 63 years), predominantly male (89% vs. 67%), and more frequently experienced injuries due to falls (82% vs. 57%). They also exhibited a higher prevalence of subaxial CS-Fxs (91% vs. 62%), fewer C0-C2 CS-Fxs (14% vs. 44%), a higher rate of associated cSCI (21% vs. 11%), and a greater tendency for surgical fixation (66% vs. 21%). We observed a 30-day mortality rate of 11% in AS patients and 5.4% in non-AS patients (p=.005).

CONCLUSIONS

The results of this study confirm the elevated risk of CS-Fxs among AS patients, although this risk appears to show a decreasing trend. The most plausible explanation for this risk reduction is the widespread application of bDMARDs.

Prognosis of Cervical Diffuse Idiopathic Skeletal Hyperostosis-Related Spine Injuries in Elderly Patients: Analyses of Both Fracture and Spinal Cord Injury Without Fracture

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

The purpose of this study was to compare the prognosis of elderly patients with injuries related to cervical diffuse idiopathic skeletal hyperostosis (cDISH) to matched control for each group, with and without fractures.

METHODS

The current multicenter study was a retrospective analysis of 140 patients aged 65 years or older with cDISH-related cervical spine injuries; 106 fractures and 34 spinal cord injuries without fracture were identified. Propensity score-matched cohorts from 1363 patients without cDISH were generated and compared. Logistic regression analysis was performed to determine the risk of early mortality for patients with cDISH-related injury.

RESULTS

Patients with cDISH-related injuries with fracture did not differ significantly in the incidence of each complication and ambulation or severity of paralysis compared to matched controls. In patients with cDISH-related injury without fracture, those who were nonambulatory at discharge comprised 55% vs 34% of controls, indicating significantly poorer ambulation in those with cDISH-related injuries (P = .023). There was no significant difference in the incidence of complications and ambulation or paralysis severity at 6 months as compared with controls. Fourteen patients died within 3 months. Logistic regression analysis identified complete paralysis (odds ratio [OR] 36.99) and age (OR 1.24) as significant risk factors for mortality.

CONCLUSIONS

The current study showed no significant differences in the incidence of complications, ambulation outcomes between patients with cDISH-related injury with fracture and matched controls, and that the ambulation at discharge for patients with cDISH-related injury without fractures were significantly inferior to those of matched controls.

Cervical spine fractures in ankylosing spondylitis patients: an analysis of the presentation and clinical results of 110 surgically managed patients in two spine centers

PURPOSE

In this work, a two-center study was performed to study the clinical presentation of cervical spine fractures in ankylosing spondylitis (AS) patients and assess the surgical management of these fractures.

METHODS

A retrospective analysis of prospectively collected data in two level-1 spine surgery centers was performed. Both spine centers have a standard database for all admitted patients. Inclusion criteria were surgically treated AS with cervical spine fracture diagnosis (from C1 to Th3) and postoperative follow-up minimum of 12 months.

RESULTS

One hundred ten patients (105 male/5 female) were included. The mean age was 62 ± 10 years. The mean time between trauma and surgery was 49 ± 42 days. There was a history of mild trauma in 72 patients (65.4%). The clinical presentation was a pain in all patients. Twenty-seven (24.6%) had a neurological deficit at admission. The most common fracture level was C6/7 in 63 patients (57.23%). The VAS was 7 ± 1, and NDI was 34 ± 8 in the preoperative assessment. The mean preoperative kyphosis angle was 48 ± 26° between C2 and C7. Positioning and preparing of the patients on the operation table took a mean of 57 ± 28 min. The surgical approach was dorsal in 59 patients (53.6%), combined in 45 patients (40.9%), and ventral in 6 patients (6,5%). The mean number of the fixed levels was 6 ± 2 levels. Intraoperative complications occurred in 9 patients (8.2%). Postoperative Cobb angle improved to a mean of 17 ± 9 degrees. Neurological improvement occurred in 20/27 patients. In 12 patients, the recovery was complete. The mean postoperative follow-up was 46 ± 18 months. VAS improved to 3 ± 1, and NDI improved to 14 ± 6 at the last postoperative visit. The improvement was clinically significant (p = 0.01 and 0.00, respectively).

CONCLUSION

High suspicion of cervical spine fractures is necessary for patients with AS. CT and MRI images are necessary to rule out cervical spine fractures in AS patients, especially to detect occult fractures. Surgical treatment is safe, and the posterior approach with long-segment fusion is the approach of choice in this group of patients.

Comparative study of halo-vest reduction and skull traction reduction in the treatment of cervical fracture dislocation in patients with ankylosing spondylitis

Background

This study aimed to investigate the safety and efficacy of the halo-vest in the treatment of cervical fracture in patients with ankylosing spondylitis (AS) and kyphosis.

Methods

From May 2017 to May 2021, 36 patients with cervical fractures with AS and thoracic kyphosis were included in this study. The patients with cervical spine fractures with AS underwent preoperative reduction by halo-vest or skull tractions. Instrumentation internal fixation and fusion surgery were then performed. The level of cervical fractures, the operative duration, blood loss, and treatment outcomes were investigated preoperatively and postoperatively.

Results

A total of 25 cases were included in the halo-vest group and 11 cases were included in the skull tractions group. The intraoperative blood loss and the surgery duration were significantly less in the halo-vest group than in the skull traction group. A comparison of American Spinal Injury Association scores at admission and final follow-up showed that the neurological function of patients improved in both groups. All patients had reached solid bony fusion during the follow-up.

Conclusion

This study presented a unique approach to use halo-vest treatment fixation of unstable cervical fracture in patients with AS. The patient should also have early surgical stabilization with a halo-vest to correct spinal deformity and avoid worsening of neurological status.

Surgical Approach to Cervical Fractures in Ankylosing Spondylitis Patients: Rationale and Surgical Strategy

BACKGROUND

Current literature lacks objective criteria to determine surgical management in patients with ankylosing spondylitis who sustain cervical fractures. The purpose of our study was to analyze the determinants for stratifying surgical approach, evaluate the outcome in patients, and postulate a management strategy.

METHODS

This was a retrospective study of patients with ankylosing spondylitis who underwent surgery for cervical spine injury with a minimum follow-up of 2 years. Neurological recovery, fracture pattern including translation and angulation, surgical duration, blood loss, and postoperative complications were recorded, and a comparative analysis of these factors with anterior, posterior, and combined surgical approaches was performed.

RESULTS

The study included 43 men with a mean age of 57 years; 49% underwent anterior-only stabilization, 16% underwent posterior-only stabilization, and 35% underwent combined anteroposterior stabilization. Mean operative time was significantly lower in anterior-only (81.4 minutes; P < 0.05) and posterior-only (124 minutes; P < 0.05) approaches compared with combined approach (266.6 minutes). Mean blood loss was significantly lower in anterior-only (87.5 mL, P < 0.05) approach compared with posterior-only (714.7 mL) and combined (912.7 mL) approaches. Mean translation was 1.8 mm, 1.7 mm, and 3.7 mm in anterior, posterior, and combined approaches (P < 0.05), respectively.

CONCLUSIONS

Our study provides insights into management of cervical spine fractures in ankylosing spondylitis patients. A fracture displacement ≤2 mm may be successfully managed by an anterior approach, while the posterior approach may be beneficial in similar fractures warranting instrumentation extending to the thoracic spine. All other fractures warrant a combined surgical approach.

Combined anterior and posterior approach in treatment of ankylosing spondylitis-associated cervical fractures: a systematic review and meta-analysis

OBJECTIVE

Cervical fractures with ankylosing spondylitis (CAS) are a specific type of spinal fracture with poor stability, low healing rate, and high disability rate. Its treatment is mainly surgical, predominantly through the anterior approach, posterior approach, and the anterior-posterior approach. Although many clinical studies have been conducted on various surgical approaches, controversy still exists concerning the choice of these surgical approaches by surgeons. The authors present here a systematic evaluation and meta-analysis exploring the utility of the anterior-posterior approach versus the anterior approach and the posterior approach.

METHODS

After a comprehensive literature search of PubMed, Cochrane, Web of Science, and Embase databases, 12 clinical studies were included in the final qualitative analysis and 8 in the final quantitative analysis. Of these studies, 11 conducted a comparison between the anterior-posterior approach and the anterior approach and posterior approaches, while one examined only the anterior-posterior approach. Where appropriate, statistical advantage ratios and 95% confidence intervals were calculated.

RESULTS

The present meta-analysis of postoperative neurological improvement showed no statistical difference in the overall neurological improvement rate between the anterior-posterior approach and anterior approach (OR 1.70, 95% CI 0.61 to 4.75; p = 0.31). However, the mean change in postoperative neurological function was lower in patients who received the anterior approach than in those who received the anterior-posterior approach (MD 0.17, 95% CI -0.02 to 0.36; p = 0.08). There was an identical trend between the anterior-posterior approach and posterior approach, with no statistically significant difference in the overall rate of neurological improvement (OR 1.37, 95% CI 0.70 to 2.56; p = 0.38). Nevertheless, the mean change in neurological function was smaller in patients receiving the anterior-posterior approach compared with the posterior approach, but there was no statistically significant difference between the two (MD 0.17, 95% CI -0.02 to 0.36; p = 0.08).

CONCLUSIONS

The results of this review and meta-analysis suggest that the benefits of the anterior-posterior approach are different from those of the anterior and posterior approaches in the treatment of ankylosing spondylitis-related cervical fractures. In a word, there is no significant difference between the cervical surgical approach and the neurological functional improvement. Therefore, surgeons should pay more attention to the type of cervical fracture, the displacement degree of cervical fracture, the spinal cord injury, the balance of cervical spine and other aspects to comprehensively consider the selection of appropriate surgical methods.

Instantaneous death risk, conditional survival and optimal surgery timing in cervical fracture patients with ankylosing spondylitis: A national multicentre retrospective study

Background

The mortality rate in patients with ankylosing spondylitis (AS) and cervical fracture is relatively high.

Objectives

This study aimed to investigate the instantaneous death risk and conditional survival (CS) in patients with AS and cervical fracture. We also studied the relationship between surgical timing and the incidence of complications.

Methods

This national multicentre retrospective study included 459 patients with AS and cervical fractures between 2003 and 2019. The hazard function was used to determine the risk of instantaneous death. The five-year CS was calculated to show the dynamic changes in prognosis.

Results

The instantaneous death risk was relatively high in the first 6 months and gradually decreased over time in patients with AS and cervical fracture. For patients who did not undergo surgery, the instantaneous risk of death was relatively high in the first 15 months and gradually decreased over time. For patients with American Spinal Injury Association impairment scale (ASIA) A and B, the 5-year CS was 55.3% at baseline, and improved steadily to 88.4% at 2 years. Odds ratios (ORs) for pneumonia, electrolyte disturbance, respiratory insufficiency, and phlebothrombosis decreased as the surgery timing increased.

Conclusion

Deaths occurred mainly in the first 6 months after injury and gradually decreased over time. Our study highlights the need for continued surveillance and care in patients with AS with cervical fractures and provides useful survival estimates for both surgeons and patients. We also observed that early surgery can significantly increase functional recovery, and decrease the incidence of complications and rehospitalisation.

Factors Associated With Major Complications and Mortality During Hospitalization in Patients With Ankylosing Spondylitis Undergoing Surgical Management for a Spine Fracture

STUDY DESIGN

Retrospective study.

OBJECTIVES

To analyze factors associated with major complications (MC) in patients with ankylosing spondylitis (AS) undergoing surgical management for a spine fracture.

METHODS

Included were all persons with spine fractures and AS in a teriary health care center between 2003 and 2019. Clinical data and MC were characterized with descriptive characteristics. Multivariable analyses were used to find factors associated with MC.

RESULTS

In total, 174 traumatic fracture incidents in 166 patients with AS were included, with a mean patient age of 70.7 ± 13.1 years. The main reason for spine fracture was minor trauma (79.9%). Spinal cord injuries (SCI) were described in 36.7% of cases. The majority of patients (54.6%) showed more than one fracture of the spine, with cervical fractures being the most common (50.5%). Overall, the incidences of surgical site infection, implant failure, nosocomial pneumonia (NP), and mortality were 17.2%, 9.2%, 31%, and 14.9%, respectively. ICU stay > 48 hours was associated with MC (including death). Posterior approach for spondylodesis, ICU stay > 48 hours and cervical SCI were related to MC (excluding death). Age > 70 years, NP and Charlson comorbidity index > 5 points were associated with in-hospital mortality.

CONCLUSIONS

Patients with AS and surgical treatment of spine fractures are at high risk for MC. Therefore, our results might give physicians better insight into the incidence and sequelae of major complications and therefore might improve patient and family expectations.

The role of an anterior approach in the treatment of ankylosing spondylitis-associated cervical fractures: a systematic review and meta-analysis

OBJECTIVE

Cervical fractures in patients with ankylosing spondylitis can have devastating neurological consequences. Currently, several surgical approaches are commonly used to treat these fractures: anterior, posterior, and anterior-posterior. The relative rarity of these fractures has limited the ability of surgeons to objectively determine the merits of each. The authors present an updated systematic review and meta-analysis investigating the utility of anterior surgical approaches relative to posterior and anterior-posterior approaches.

METHODS

After a comprehensive literature search of the PubMed, Cochrane, and Embase databases, 7 clinical studies were included in the final qualitative and 6 in the final quantitative analyses. Of these studies, 6 compared anterior approaches with anterior-posterior and posterior approaches, while 1 investigated only an anterior approach. Odds ratios and 95% confidence intervals were calculated where appropriate.

RESULTS

A meta-analysis of postoperative neurological improvement revealed no statistically significant differences in gross rates of neurological improvement between anterior and posterior approaches (OR 0.40, 95% CI 0.10-1.59; p = 0.19). However, when analyzing the mean change in neurological function, patients who underwent anterior approaches had a significantly lower mean change in postoperative neurological function relative to patients who underwent posterior approaches (mean difference [MD] -0.60, 95% CI -0.76 to -0.45; p < 0.00001). An identical trend was seen between anterior and anterior-posterior approaches; there were no statistically significant differences in gross rates of neurological improvement (OR 3.05, 95% CI 0.84-11.15; p = 0.09). However, patients who underwent anterior approaches experienced a lower mean change in neurological function relative to anterior-posterior approaches (MD -0.46, 95% CI -0.60 to -0.32; p < 0.00001). There were no significant differences in complication rates between anterior approaches, posterior approaches, or anterior-posterior approaches, although complication rates trended lower in patients who underwent anterior approaches.

CONCLUSIONS

The results of this review and meta-analysis demonstrated the varying benefits of anterior approaches relative to posterior and anterior-posterior approaches in treatment of cervical fractures associated with ankylosing spondylitis. While reports demonstrated lower degrees of neurological improvement in anterior approaches, they may benefit patients with less-severe injuries if lower complication rates are desired.

Open versus minimally invasive fixation of thoracic and lumbar spine fractures in patients with ankylosing spinal diseases

Purpose

Posterior multilevel fixation of traumatic instability in ankylosing spinal disease (ASD) can be performed by open surgery (OS) or minimally invasive surgery (MIS). We investigated whether both methods differ based on the reduction results and perioperative parameters.

Methods

In this retrospective cohort study, OS and MIS groups were investigated. The bisegmental Cobb angles and dislocation angles were measured using pre- and postoperative CT images, and the initial malalignment and achieved reduction were calculated. Cut-seam time, calculated blood loss, transfusion number, fluoroscopy time, pedicle screw placement accuracy, duration of ICU stay, in-patient stay, and complications (bleeding, postoperative thrombosis and embolism, and postoperative mortality) were recorded.

Results

Seventy-five ASD patients with spine fractures (Ø 75 ± 11 years, male: 52, female: 23) (MIS: 48; OS: 27) were included in this study. The extent of reduction did not differ in the OS and MIS groups (p = 0.465; MIS:− 1 ± 3°, OS:−2 ± 6°). The residual postoperative malalignment angle was not significantly different (p = 0.283). Seventy-eight of the implanted screws (11%) showed malpositioning. No difference was found between OS and MIS (MIS, 37 [7%]; OS, 41 [16%]; p = 0.095). MIS was associated with less blood loss (OS: 1.28 ± 0.78 l, MIS: 0.71 ± 0.57 l, p = 0.001), cut-seam time (MIS: 98 ± 44 min, OS: 166 ± 69 min, p < 0.001), and hospital stay (MIS: Ø14 ± 16 d, OS: Ø38 ± 49 d, p = 0.02) than OS.

Conclusion

OS and MIS show equally limited performance in terms of the fracture reduction achieved. The MIS technique was superior to OS based on the perioperative outcome. Therefore, MIS should be preferred over OS for unstable spinal injuries, excluding C-type fractures, in ASD patients without neurological impairment.

Whole Spine CT Scan for the Detection of Acute Spinal Fractures in Diffuse Idiopathic Skeletal Hyperostosis Patients Who Sustained Low-energy Trauma

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to evaluate the role and value of whole-spine computerized tomography (WSCT) versus radiographs and targeted CT to tender spinal regions in patients with diffuse idiopathic skeletal hyperostosis (DISH) after low-energy trauma.

SUMMARY OF BACKGROUND DATA

Subjects with DISH are prone to spinal fractures even after low-impact trauma due to a rigid spinal structure.

METHODS

One-hundred forty-seven subjects (average age: 83 years, M:F 64/83) with verified DISH (Resnick and Niwayama radiographic criteria) on WSCT who were admitted to the emergency room (ER) after low-energy trauma and for whom there were radiographs of at least the thoracic and lumbar spine were evaluated for the presence of acute spinal fractures on both radiographs and WSCT. Agreement between fracture location and spinal tenderness location (cervical, thoracic, or lumbar) as reported in the medical record was evaluated.

RESULTS

Significantly more acute fractures were detected on WSCT compared to radiographs (55 and 32, P < 0.00001, respectively). The site of tenderness was not indicative of the fractured spinal segment in 57% of all acute fractures (seven cervical, 15 thoracic, and 16 lumbar). No fracture was detected on WSCT in 10 subjects with an unspecified pain location. Multilevel distant fractures were detected in two patients with a specified pain location to only one of the fractures.

CONCLUSION

WSCT in DISH subjects after low-impact trauma is mandatory due to the high prevalence of acute fractures and the low specificity for fracture detection on radiographs. A targeted CT approach to the tender spinal segment proved to be inadequate and would have missed 57% of the acute single fractures with incompatible spinal tenderness location. These results support the significant role of WSCT in the ER setting for detecting and pinpointing the spinal fracture site of DISH subjects who present with low-impact trauma.

LEVEL OF EVIDENCE

3.

Incidence of diffuse idiopathic skeletal hyperostosis from a model of dysphagia

OBJECTIVE

To relate symptoms of dysphagia to Forestier-Rotes Querol disease or diffuse idiopathic skeletal hyperostosis (DISH), a disorder due to ossification in the anterior longitudinal ligament and calcifications in other entheses.

PATIENTS AND METHODS

Review of clinical and radiological findings in 455 outpatients attended at our Centre with dysphagia, for 5years, referred from dental, trauma, neurological or primary health care. A diagnosis of DISH was established using Resnick's criteria.

RESULTS

We detected 51 cases with dysphagia consistent with DISH diagnostic criteria - 11.2% of subjects suffering this symptom- out of 32544 outpatients attended. An incidence of 7:100000 inhabitants per year was observed. Two cases showed significant improvement after removing the new bone in the spine.

CONCLUSIONS

DISH is an ankylosing ossification between the joints, frequently systemic but showing no clinical symptoms. When symptoms manifest, neck movements and upper airways are involved, mainly dysphagia. A few cases need surgery to relieve the calcification processes.

Injuries to the Rigid Spine: What the Spine Surgeon Wants to Know

The biomechanical stability of the spine is altered in patients with a rigid spine, rendering it vulnerable to fracture even from relatively minor impact. The rigid spine entities are ankylosing spondylitis (AS), diffuse idiopathic skeletal hyperostosis, degenerative spondylosis, and a surgically fused spine. The most common mechanism of injury resulting in fracture is hyperextension, which often leads to unstable injury in patients with a rigid spine per the recent AOSpine classification system. Due to the increased risk of spinal fractures in this population, performing a spine CT is the first step when a patient with a rigid spine presents with new back pain or suspected spinal trauma. In addition, there should be a low threshold for performing a non-contrast-enhanced spine MRI in patients with a rigid spine, especially those with AS who may have an occult fracture, epidural hematoma, or spinal cord injury. Unfortunately, owing to insufficient imaging and an unfamiliarity with fracture patterns in the setting of a rigid spine, fracture diagnosis is often delayed, leading to significant morbidity and even death. The radiologist's role is to recognize the imaging features of a rigid spine, identify any fractures at CT and MRI, and fully characterize the extent of injury. Reasons for surgical intervention include neurologic deficit or concern for deterioration, an unstable fracture, or the presence of an epidural hematoma. By understanding the imaging features of various rigid spine conditions and vigilantly examining images for occult fractures, the radiologist can avoid a missed or delayed diagnosis of an injured rigid spine. ^©RSNA, 2019.

Finite Element Analysis of Long Posterior Transpedicular Instrumentation for Cervicothoracic Fractures Related to Ankylosing Spondylitis

STUDY DESIGN

Biomechanical finite element model analysis.

OBJECTIVES

Spinal fractures related to ankylosing spondylitis (AS) are often treated by long posterior stabilization. The objective of this study is to develop a finite element model (FEM) for spinal fractures related to AS and to establish a biomechanical foundation for long posterior stabilization of cervicothoracic fractures related to AS.

METHODS

An existing FEM (consisting of 2 separately developed models) including the cervical and thoracic spine were adapted to the conditions of AS (all discs fused, C0-C1 and C1-C2 mobile). A fracture at the level C6-C7 was simulated. Besides a normal spine (no AS, no fracture) and the uninstrumented fractured spine 4 different posterior transpedicular instrumentations were tested. Three loads (1.5g, 3.0g, 4.5g) were applied according to a specific load curve.

RESULTS

All posterior stabilization methods could normalize the axial stability at the fracture site as measured with gap distance. The maximum stress at the cranial instrumentation end (C3-C4) was slightly greater if every level was instrumented, than in the skipped level model. The skipped level instrumentation achieved similar rotatory stability as the long multilevel instrumentation.

CONCLUSIONS

Skipping instrumentation levels without giving up instrumentation length reduced stresses in the ossified tissue within the range of the instrumentation and did not decrease the stability in a FEM of a cervicothoracic fracture related to AS. Considering the risks associated with every additional screw placed, the skipped level instrumentation has advantages regarding patient safety.

Selective mortality in middle-aged American women with Diffuse Idiopathic Skeletal Hyperostosis (DISH)

OBJECTIVE

A mortality sample of white American male and female skeletons was examined to illustrate a simple means of identifying skeletal conditions associated with an increased risk of dying relatively early in adulthood and to determine if males and females with Diffuse Idiopathic Skeletal Hyperostosis (DISH) displayed the same general age-specific pattern of mortality.

METHODS

Age-specific probability distributions for DISH were generated from 416 white Americans who died from the 1980s to the present, and whose remains were donated to the University of Tennessee Forensic Anthropology Center. The age-specific frequency of DISH is analyzed using an empirical smoothing algorithm. Doing so allows for the identification of deviations (i.e., local maxima) from monotonically increasing age-specific probabilities.

RESULTS

In females (N = 199), there is a peak in the frequency of individuals with DISH around 60 years of age where 37.0% of the individuals have DISH. It is matched only by the frequency (38.7%) in the oldest females, those over 85 years old. In contrast, DISH frequencies for males (N = 217) increase monotonically with advancing age, reaching 62.5% in the ≥86 years age group. There was an association between DISH and high body weight in women, particularly those who died before they reached the age of 75.

CONCLUSIONS

Early-onset DISH in white American women is associated with an increased risk of dying indicated by a local maximum in the probability curve. Should this finding be replicated in additional mortality samples and the reason DISH is associated with early death is established, beyond being heavy, this radiologically visible ossification of the spine could be a potential component of health-monitoring programs for middle-aged women.

The importance of the occipitocervical area in patients with ankylosing spondylitis analysis of a cohort of 86 cervical fractures in surgically treated patients

Study Design

This was a retrospective analysis of prospectively collected data.

Objective

The effect of C0-C1-C2 cervical ankylosis in patients with ankylosing spondylitis (AS) is not documented. The objective of this study is to describe the radiological characteristics of the occipitocervical junction in patients with AS operated for a cervical fracture and to correlate them with their clinical evolution.

Materials and Methods

Analysis of patients with ankylosing spondylitis (AS) treated in a single institution of a cervical vertebral fracture between 2007 and 2014 who were prospectively followed through the SWESPINE registry. The integrity of the C0-C1-C2 joints was determined and classified into fused and nonfused joints. By determining the angle between C0-C1 and C1-C2 joints in the coronal view of the computed tomography scan (X-angle), the progressive degeneration of these joints was described. Intra- and inter-observer reliability of this test was determined. The instruments of health-related quality of life (QOL) and disability were EQ5D and Oswestry disability index (ODI), respectively.

Results

A total of 86 patients with AS treated surgically for cervical fracture had complete facet ankylosis between C3 and T1 due to their pathology. Mean age 69.2 years (standard deviation [SD]: 11.7). The most common level of fracture was in C5-C6. In 24 patients, the C0-C1 joint was fused, and in 15 patients, C1-C2 joint was fused. The intra- and inter-class reliabilities for X-angle measurement were very high (intraclass correlation coefficients = 0.94; 0.92). The mean X-angle was 125° (SD: 12) in nonfused patients and 136° (SD: 14) in fused patients (P < 0.001). There were no differences in QOL and disability at 2 years between the two groups: EQ5D-index of 0.54 and 0.55 (P = 0.5), ODI of 26.4 and 24, (P = 0.35) respectively.

Conclusions

X-angle is a reliable measure for joint integrity C0-C1-C2 in patients with AS. Total cervical ankylosis including the C0-C1-C2 segments is not related to poorer QOL and disability in these patients.