Surgical Stabilization Improves Survival of Spinal Fractures Related to Ankylosing Spondylitis

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 8-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.

Surgical outcomes of robotic-assisted percutaneous fixation for thoracolumbar fractures in patients with ankylosing spondylitis

BACKGROUND

Spinal fractures in patients with ankylosing spondylitis (AS) mainly present as instability, involving all three columns of the spine, and surgical intervention is often considered necessary. However, in AS patients, the significant alterations in bony structure and anatomy result in a lack of identifiable landmarks, which increases the difficulty of pedicle screw implantation. Therefore, we present the clinical outcomes of robotic-assisted percutaneous fixation for thoracolumbar fractures in patients with AS.

METHODS

A retrospective review was conducted on a series of 12 patients diagnosed with AS. All patients sustained thoracolumbar fractures between October 2018 and October 2022 and underwent posterior robotic-assisted percutaneous fixation procedures. Outcomes of interest included operative time, intra-operative blood loss, complications, duration of hospital stay and fracture union. The clinical outcomes were assessed using the visual analogue scale (VAS) and Oswestry Disability Index (ODI). To investigate the achieved operative correction, pre- and postoperative radiographs in the lateral plane were analyzed by measuring the Cobb angle.

RESULTS

The 12 patients had a mean age of 62.8 ± 13.0 years and a mean follow-up duration of 32.7 ± 18.9 months. Mean hospital stay duration was 15 ± 8.0 days. The mean operative time was 119.6 ± 32.2 min, and the median blood loss was 50 (50, 250) ml. The VAS value improved from 6.8 ± 0.9 preoperatively to 1.3 ± 1.0 at the final follow-up (P < 0.05). The ODI value improved from 83.6 ± 6.1% preoperatively to 11.8 ± 6.6% at the latest follow-up (P < 0.05). The average Cobb angle changed from 15.2 ± 11.0 pre-operatively to 8.3 ± 7.1 at final follow-up (P < 0.05). Bone healing was consistently achieved, with an average healing time of 6 (5.3, 7.0) months. Of the 108 screws implanted, 2 (1.9%) were improperly positioned. One patient experienced delayed nerve injury after the operation, but the nerve function returned to normal upon discharge.

CONCLUSION

Posterior robotic-assisted percutaneous internal fixation can be used as an ideal surgical treatment for thoracolumbar fractures in AS patients. However, while robot-assisted pedicle screw placement can enhance the accuracy of pedicle screw insertion, it should not be relied upon solely.

Surgical Management Thoracolumbar Fractures in Patients with Ankylosing Spondylitis: Technical Note with Case Series

OBJECTIVE

Ankylosing spondylitis (AS) is a chronic inflammatory joint disease. Complications such as traumatic spinal fractures are mostly caused by hyperextension and are unstable. We report the cases of 5 patients with AS surgically treated for thoracolumbar fractures.

METHODS AND RESULTS

We shared our experience of posterior stabilization surgery performed for the treatment of thoracolumbar fractures after traumas such as fall-accident in patients with AS. Patients were all men, and their ages were between 52 and 77 years. The first 3 patients woke up with neurologic deficits and were managed surgically under general anesthesia. We managed the last 2 patients with unilateral short-level stabilization under local anesthesia followed by bilateral long-level stabilization under general anesthesia. No neurologic deterioration was found in the postoperative examination of these 2 patients. We assume that the reason for neurologic deterioration after general anesthesia is the relaxation of muscles. All 3 columns of the spine are affected in patients with AS and the stability is provided by the tone of the muscles around the spine.

CONCLUSIONS

To prevent postoperative neurologic complications after the surgical treatment of traumatic hyperextension thoracic and lumbar fractures in patients with AS, we recommend securing the fracture level with unilateral short-level stabilization under local anesthesia and then completing the operation with general anesthesia.

Perioperative risk stratification of spine trauma patients with ankylosing spinal disorders: a comparison of 3 quantitative indices

OBJECTIVE

Patients with ankylosing spinal disorders (ASDs), including ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH), have been shown to experience significantly increased rates of postoperative complications. Despite this, very few risk stratification tools have been validated for this population. As such, the purpose of this study was to identify predictors of adverse events and mortality in ASD patients undergoing surgery for 3-column fractures.

METHODS

All adult patients with a documented history of AS or DISH who underwent surgery for a traumatic 3-column fracture between 2000 and 2020 were identified. Perioperative variables, including comorbidities, time to diagnosis, and number of fused segments, were collected. Three instruments, including the Charlson Comorbidity Index (CCI), modified frailty index (mFI), and Injury Severity Score (ISS), were computed for each patient. The primary outcomes of interest included 1-year mortality, as well as postoperative complications.

RESULTS

A total of 108 patients were included, with a mean ± SD age of 73 ± 11 years. Of these, 41 (38%) experienced at least 1 postoperative complication and 22 (20.4%) died within 12 months after surgery. When the authors controlled for potential known confounders, the CCI score was significantly associated with postoperative adverse events (OR 1.20, 95% CI 1.00-1.42, p = 0.045) and trended toward significance for mortality (OR 1.19, 95% CI 0.97-1.45, p = 0.098). In contrast, mFI score and ISS were not significantly predictive of either outcome.

CONCLUSIONS

Complications in spine trauma patients with ASD may be driven by comorbidity burden rather than operative or injury-related factors. The CCI may be a valuable tool for the evaluation of this unique population.

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.

Treatment of ankylosing spondylitis complicated with a thoracolumbar Andersson lesion by posterior closed osteotomy, debridement and fusion through the fracture line

Background

An Andersson lesion (AL) is a fatigue fracture occurring across three columns in ankylosing spondylitis (AS), resulting in spinal pseudarthrosis (SP) formation, most commonly in the thoracolumbar segment. However, there is still great controversy and few reports on the best surgical method for the treatment of AS combined with thoracolumbar AL. The purpose of this study was to investigate the efficacy of posterior closed osteotomy, debridement and fusion through the fracture line for the treatment of this disease.

Methods

The clinical data of 13 patients (male 8, female 5, mean age 50.6 years) with AS combined with thoracolumbar AL treated with posterior closed osteotomy, debridement and fusion through the fracture line were retrospectively analysed. The following parameters of the full-length lateral spine radiographs were measured preoperatively and at the last follow-up: cervical 7 tilt (C₇T), global kyphosis (GK), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), local kyphosis (LK), angle of the fusion levels (AFL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and sagittal vertical axis (SVA). The visual analog scale (VAS), Oswestry disability index (ODI) and Scoliosis Research Society-22 (SRS-22) scores were recorded preoperatively and at the last follow-up.

Results

The mean operation time was 345 min, the mean blood loss was 673 mL, and the mean follow-up time was 21.9 months. Compared with the preoperative values, the C₇T, GK, TK, TLK, LK, AFL, PT, SS and SVA values of all patients were significantly improved at the last follow-up (P < 0.05); GK improved from 81.62 ± 16.11 to 50.15 ± 8.55, with an average of 31° of correction (F = 75.945, P<0.001). The VAS, ODI and SRS-22 scores also significantly improved (P < 0.05). At the last follow-up, bone fusion was found in all fracture ends. One patient developed numbness in the lower limbs after surgery and recovered after 3 months of rehabilitation; none of the remaining patients experienced postoperative complications.

Conclusions

Posterior closed osteotomy, debridement and fusion through the fracture line completely removes the necrotic tissue around the SP, relieves symptoms, and corrects kyphosis simultaneously. It reduces the tension behind the fracture line or changes the tension into compressive stress, enabling stable repair of the fracture and avoiding anterior surgery. It is a safe and effective operation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05770-3.

The Prevalence and Characteristics of Diffuse Idiopathic Skeletal Hyperostosis (DISH): A Cross-Sectional Study of 1519 Japanese Individuals

Background: Diffuse idiopathic skeletal hyperostosis (DISH) is a pathology characterized by enthesis ossification, but there have been few reports on epidemiological surveys. This report presents a cross-sectional survey of DISH from thoracic to sacral spine in patients at the tertiary emergency medical center. Methods: The patients were divided into DISH (+) group and DISH (−) group for a retrospective comparative study. The primary outcome measures were the frequency of DISH and the patient demographic data, the secondary outcome measures were the previous medical history (diabetes mellitus, cardiovascular disease), the extent of aortic calcification, the frequency of hyperostosis around the costovertebral joint and the mortality rate within 3 months of the initial examination. Results: This survey examined a total of 1519 patients. There were 265 cases (17.4%) in the DISH (+) group and 1254 cases in DISH (−) group. The prevalence of DISH was concentrated at the thoracolumbar junction, particularly at T9. The mean age, ratio of male and hyperostosis around the costovertebral joint were significantly higher in the DISH (+) group (p < 0.001), but there was no significant difference in other variables. Conclusions: The pathology of DISH might involve the effects of age-related changes or biomechanical effects.

Spinal Fractures in Ankylosing Spondylitis: Patterns, Management, and Complications in the United States - Analysis of Latest Nationwide Inpatient Sample Data

Objective

Ankylosing spondylitis (AS) is a rheumatic inflammatory disease marked by chronic inflammation of the axial skeleton. This condition, particularly when severe, can lead to increased risk of vertebral fractures attributed to decreased ability of the stiffened spinal column to sustain normal loads. However, little focus has been placed on understanding the locations of spinal fractures and associated complications and assessing the correlation between these. In this review, we aim to summarize the complications and treatment patterns in the United States in AS patients with spinal fractures, using the latest Nationwide Inpatient Sample (NIS) database (2016–2018).

Methods

We analyzed the NIS data of years 2016–2018 to compare the fracture patterns and complications.

Results

A total of 5,385 patients were included. The mean age was 71.63 years (standard deviation [SD], 13.21), with male predominance (83.8%). The most common population is Whites (77.4%), followed by Hispanics (7.9%). The most common fracture level was thoracic level (58.3%), followed by cervical level (38%). Multiple fracture levels were found in 13.3% of the patients. Spinal cord injury (SCI) was associated with 15.8% of the patients. The cervical level had a higher proportion of SCI (26.5%), followed by thoracic level (9.2%). The mean Elixhauser comorbidity score was 4.82 (SD, 2.17). A total of 2,365 patients (43.9%) underwent surgical treatment for the fractures. The overall complication rate was 40.8%. Respiratory complications, including pneumonia and respiratory insufficiency, were the predominant complications in the overall cohort. Based on the regression analysis, there was no significant difference (p=0.45) in the complication rates based on the levels. The presence of SCI increased the odds of having a complication by 2.164 times (95% confidence interval, 1.722–2.72; p≤0.001), and an increase in Elixhauser comorbidity score predicted the complication and in-hospital mortality rate (p≤0.001).

Conclusion

AS patients with spinal fractures have higher postoperative complications than the general population. The most common fracture location was thoracic in our study, although it differs with few studies, with SCI occurring in 1/6th of the patients.

Impact of age on mortality and complications in patients with Ankylosing Spondylitis spine fractures

OBJECTIVE

The aim of this retrospective cohort study was to study the impact of age on in-hospital complications and mortality following surgery for Ankylosing Spondylitis (AS) associated spine fractures.

METHODS

We extracted data from the Nationwide Inpatient Sample (NIS) database (1998-2018) using ICD-9/10 codes. Patients with a primary diagnosis of AS associated spine fractures who underwent fusion surgery were included. Complications and in-hospital mortality were analyzed.

RESULTS

A total cohort of 8526 patients was identified. Overall, the median age of the cohort was 69 years. AS associated fractures were equally distributed among cervical and thoracolumbar regions. Overall, complications were noted in 48% of patients and pulmonary complications were the most common (32%) followed by renal (13%) and infection (12%). Complications were seen in 57.3% of patients ≥ 70 years of age compared to 38.4% of patients < 70 years of age (p < .0001). Also, 9.9 % of patients ≥ 70 years of age had in-hospital mortality compared to 3.1 % of patients < 70 years of age (p < .0001). Based on surgical approaches, elderly patients (≥70 years) who underwent anterior, posterior, and anterior + posterior approaches had 19.8%, 7.4% and 16.4% in-hospital mortality compared to 5.3%, 2.2% and 7.4% respectively for patients < 70 years.

CONCLUSIONS

Elderly patients (≥70 years of age) were 3.2 times more likely to have in-hospital mortality and higher complications compared to younger patients (57% vs. 38%). Cervical compared to thoracolumbar fractures and anterior compared to posterior surgical approaches were associated with higher complications and in-hospital mortality.

Percutaneous instrumentation with cement augmentation for traumatic hyperextension thoracic and lumbar fractures in ankylosing spondylitis: a single-institution experience

OBJECTIVE

The typical traumatic thoracolumbar (TL) fracture in patients with ankylosing spondylitis (AS) is a hyperextension injury involving all three spinal columns, which is associated with unfavorable outcomes. Although a consensus on the management of these highly unstable injuries is missing, minimally invasive surgery (MIS) has been progressively accepted as a treatment option, since it is related to lower morbidity and mortality rates. This study aimed to evaluate clinical and radiological outcomes after percutaneous instrumentation with cement augmentation for hyperextension TL fractures in patients with AS at a single institution.

METHODS

This cohort study was completed retrospectively. Back pain was assessed at preoperative, postoperative, and final follow-up visits using the visual analog scale (VAS). Patient-reported outcomes via the Oswestry Disability Index (ODI) and the new mobility score (NMS) were obtained to assess disability and mobility during follow-up. Radiological outcomes included the Cobb angle, sagittal index (SI), union rate, and implant failure. Intra- and postoperative complications were recorded.

RESULTS

A total of 22 patients met inclusion criteria. The mean patient age was 74.2 ± 7.3 years with a mean follow-up of 39.2 ± 17.4 months. The VAS score for back pain significantly improved over the follow-up period (from 8.4 ± 1.1 to 2.8 ± 0.8, p < 0.001). At the last follow-up, all patients had minor disability (mean ODI score 24.4 ± 6.1, p = 0.003) and self-sufficiency of mobility (mean NMS 7.5 ± 1.6, p = 0.02). The Cobb angle (5.2° ± 2.9° preoperatively to 4.4° ± 3.3° at follow-up) and SI (7.9° ± 4.2° to 8.8° ± 5.1°) were maintained at follow-up, showing no loss of segmental kyphosis. Bone union was observed in all patients. The overall complication rate was 9.1%, while the reoperation rate for implant failure was 4.5%.

CONCLUSIONS

Percutaneous instrumentation with cement augmentation for traumatic hyperextension TL fractures in AS demonstrated good clinical and radiological outcomes, along with a high bone union level and low reoperation rate. Accordingly, MIS reduced the complication rate in the management of these injuries of the ankylosed spine.

Whole-Spine Magnetic Resonance Imaging: A Review of Suggested Indications

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The spinal column has a propensity for lesions to manifest in a multifocal manner, and identification of the lesions can be difficult.

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When used to image the spine, magnetic resonance imaging (MRI) most accurately identifies the presence and location of lesions, guiding the treatment plan and preventing potentially devastating complications that are known to be associated with unidentified lesions.

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Certain conditions clearly warrant evaluation with whole-spine MRI, whereas the use of whole-spine MRI with other conditions is more controversial.

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We suggest whole-spine MRI when evaluating and treating any spinal infection, lumbar stenosis with upper motor neuron signs, ankylosing disorders of the spine with concern for fracture, congenital scoliosis undergoing surgical correction, and metastatic spinal tumors.

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Use of whole-spine MRI in patients with idiopathic scoliosis and acute spinal trauma remains controversial.

Percutaneous, PMMA-augmented, pedicle screw instrumentation of thoracolumbar ankylotic spine fractures

Introduction

Fractures in the ankylotic spine may have an insidious presentation but are prone to displace with devastating consequences. The long lever arm of ankylosed spine fragments may lead to pulmonary and great vessel injury and is difficult to adequately immobilize. Conservative treatment will produce in many cases poor outcomes with high morbidity and mortality. Open surgical treatment is also fraught with technical difficulties and can lead to major blood loss and prolonged operative times.

In recent years, percutaneous instrumentation of non-ankylotic spine fractures has gained popularity, producing similar outcomes to open surgery with shorter operative times and reduced blood loss and hospital length of stay. We describe our experience implementing these techniques in ankylotic spine patients.

Methods

We retrospectively retrieved from our hospital’s electronic health records all patients treated for thoracolumbar spine fractures between 2008 and 2015 with a diagnosis of ankylosing spondylitis (AS) or diffuse idiopathic skeletal hyperostosis (DISH). Operative and postoperative data, results, and complications were tabulated, and radiographic parameters were evaluated.

Results

Twenty-four patients with ankylotic spine disease underwent percutaneous augmented instrumentation between 2008 and 2015. The mean age was 76. All patients had at least one comorbidity. The mean number of ankylosed levels was 14. Mean operative time was 131 min. The average postoperative hemoglobin decrease was 1.21 gr/%, with only 4 patients requiring blood transfusion.

45.8% of the patients had postoperative medical complications. One patient (4.2%) had a superficial postoperative infection, and one patient died in hospital. The average hospital length of stay was 14.55 days.

All patients retained their preoperative ASIA grades, and 3 improved one grade. All patients united their fractures without losing reduction.

Conclusions

PMMA-augmented percutaneous instrumentation is an attractive surgical option for this difficult patient subset, especially when compared to other available current alternatives.

Diffuse idiopathic skeletal hyperostosis: Etiology and clinical relevance

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic bone-forming condition characterized by the presence of at least three bony bridges at the anterolateral spine. The aim of this review was to address the present state of pathophysiological knowledge, the clinical relevance, and diagnosis of DISH. The pathogenesis of DISH is currently unknown. The presence of DISH has been associated with older age, male sex, obesity, hypertension, atherosclerosis, and diabetes mellitus. Because the new bone forms mainly at entheseal sites, local fibroblasts, chondrocytes, collagen fibers, and calcified matrix are probably influenced by genetic, vascular, metabolic, and mechanical factors. Diagnosing the presence of DISH is of clinical importance, because the risk of a spinal fracture increases and associations with the metabolic syndrome, coronary and aortic disease, and respiratory effects are strong. Unravelling the pathogenesis of DISH can impact the field of regenerative medicine and bone tissue regeneration.

Magnetic resonance tomography for the early detection of occult fractures of the spinal column in patients with ankylosing spondylitis

Purpose

The purpose of this study was to determine the extent to which magnetic resonance imaging (MRI) performed in patients with ankylosing spondylitis (AS) after low- and no-energy trauma leads to an improved diagnosis and, as a result, to a change in the therapeutic strategy.

Methods

All patients with AS, who underwent surgery after minor traumas (low-energy traumas, LETs) and patients without trauma history (NET: no-energy trauma), were retrospectively analysed. The diagnostic and planned surgical procedure was examined initially and again after total spine MRI in patients with persistent and/or new complaints.

Results

One hundred and thirty-six patients with AS after trauma were surgically treated. A total of 92 patients with LETs and 12 patients with NETs were included. After initial diagnostics (CT and X-ray) were performed in 15.4% of the patients with LET or NET (n = 16), we found occult fractures on MRI scans. In ten of these patients (6 LET, 4 NET) in which a previous decision was made to follow conservative therapy, no fracture indication was found on CT or X-ray. Two fracture heights were observed in six patients who experienced LET. However, on X-ray and CT, the fractures were only visible at one height. All fractures were treated surgically with stabilization and decompression if indicated.

Conclusion

Considering the high percentage of our patient population with occult fractures, we recommend supplementing the basic diagnostic procedures with an MRI of the entire spinal column in patients with painful spinal column findings after minor trauma and for those with persistent pain without trauma.

Graphic abstract

These slides can be retrieved under Electronic Supplementary Material.

The surgical treatment strategies for thoracolumbar spine fractures with ankylosing spondylitis: a case report

Background

Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily affects spine and paraspinal soft tissue. Ankylosing spondylitis is one of the causes of osteoporosis and patients with ankylosing spondylitis tend to have spinal fractures due to limited mobility and osteoporosis. In recent years, due to the increase in the number of patients with AS, patients with AS and thoracolumbar spine fractures have gradually increased. In the past 1 year, we have treated 3 cases of AS with thoracolumbar spine fractures via simple posterior internal fixation and this paper aims to report its clinic effect.

Case presentation

All the three patients selected had a history of ankylosing spondylitis for nearly 30 years, and one of them developed a thoracolumbar spine fracture after falling when he walked, and the other two developed a thoracolumbar spine fracture without any reason. They were hospitalized for “low back pain” and were diagnosed as fractures after careful physical examination and imaging examinations such as X-ray, CT, and MRI. After the preoperative preparation was completed, all the three patients underwent surgery with simple posterior internal fixation-reduction of the fracture and pedicle screw fixation via posterior approach. All the implants-pedicle screws and connecting rods-are made of titanium alloy. For postoperative management, we asked all the patients to stay in bed for 3 weeks after the operation, and then slowly move down with the help of crutches. Fracture healing and neurological function recovery were observed postoperatively. All the three patients recovered satisfactorily after surgery, and the follow-up confirmed that the fracture healed successfully after 3 months.

Conclusions

The 3 patients included 2 men and 1 women. All the 3 patients recovered well after surgery, and the follow-up confirmed that the fracture healed successfully after 3 months. One man developed urination dysfunction after operation and recovered to normal 3 months after rehabilitation exercise.

Regional Differences in Diffuse Idiopathic Skeletal Hyperostosis: A Retrospective Cohort Study from Sweden and Japan

STUDY DESIGN

We retrospectively reviewed computed tomography (CT) records of patients in Japan and Sweden, which are both aging populations.

OBJECTIVE

To research the influence of ethnicity and region on diffuse idiopathic skeletal hyperostosis (DISH) prevalence.

SUMMARY OF BACKGROUND DATA

DISH can complicate non-surgical treatment of spinal fractures and often requires surgical intervention. We previously reported a prevalence of DISH in Japan that was higher than that reported in other studies.

METHODS

We retrospectively reviewed CT records of patients in Japan and Sweden, which have both aging populations. Patients undergoing whole body CT during trauma examinations at an acute outpatient clinic in Uppsala University Hospital in a 1-year period were eligible for inclusion. Excluded were those less than 40 and more than or equal to 90 years old, and those with previous spinal surgery. The prevalence of DISH by sex and age was determined according to radiographic criteria by Resnick. Results from Sweden were compared with the Japan data, which we previously reported.

RESULTS

Age of the eligible subjects (265 men and 153 women) ranged from 40 to 89 years, with a mean age of 63.4 years. Among men, 86 (32.5%) were diagnosed with DISH, and the results by age (40s, 50s, 60s, 70s, and 80s) were: 6 (10.7%), 13 (22%), 35 (46.1%), 17 (34%), and 15 (62.5%) patients, respectively. Among women, 16 (10.5%) had DISH, and the results by age were as follows: 1 (2.6%), 1 (3.3%), 2 (6.7%), 6 (22.2%), and 6 (22.2%) patients, respectively. These results did not differ from those previously published for Japan (Fisher exact test, men: P = 1, 0.27, 0.12, 0.06, and 1, respectively; women: P = 0.49, 0.62, 0.5, 0.8, and 0.3, respectively).

CONCLUSION

The presented cohort study revealed that ethnicity and region may not be notable factors of DISH prevalence, since patients from both Japan and Sweden had similar DISH prevalence.

LEVEL OF EVIDENCE

3.

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.

Minimally invasive stabilization of the fractured ankylosed spine: a comparative case series study

Background

To compare the outcome of minimally invasive fracture stabilization to traditional open methods in the thoracolumbar region in patients with an ankylosing disorder of the spine.

Methods

A prospective, ethics-approved database (Spine Tango) at a tertiary referral center was retrospectively reviewed for results of surgery on fractures of the ankylosed thoracolumbar spine. These were then split by surgical technique into two cohorts: minimally invasive surgical fixation (MIS group) or standard open surgery (open group).

Results

We identified 17 patients who presented with fractures in an ankylosed spine from 2010 to 2017. MIS fixation was performed on 10 and open surgery and fixation on 7. Average age in the MIS group was older than the traditional cohort. There was no difference in the average number of levels stabilized (open =6.9, MIS =7). There was a shorter duration in the operative time and a significant difference in blood loss in favor of the MIS group (P=0.00079). Radiation exposure time and dose were significantly higher in the MIS group (P=0.006). There were no cases of non-union, implant malposition or failure in either group. Two significant complications occurred with the death of one patient in the MIS group, and one death in the open group.

Conclusions

The MIS technique for fractures of the ankylosed spine has shown an acceptable complication rate and good results comparable to open surgery for a high-risk patient population.

Do biological disease-modifying antirheumatic drugs reduce the spinal fracture risk related to ankylosing spondylitis? A longitudinal multiregistry matched cohort study

OBJECTIVES

Ankylosing spondylitis (AS) is associated with an increased spinal fracture risk due to the loss of elasticity in spinal motion segments. With the introduction of biological disease-modifying antirheumatic drug (bDMARD) treatment for AS, the individual course of the disease has been ameliorated. This study aims to examine the association of bDMARD treatment and risk of spinal fracture.

DESIGN

Longitudinal population-based multiregistry observational matched cohort study.

SETTING

Swedish Patient Registry 1987-2014 and Swedish Prescribed Drugs Registry 2005-2014.

PARTICIPANTS

Included were patients ≥18 years of age receiving treatment at a healthcare facility for the primary diagnosis of AS. About 1352 patients received more than one prescription of bDMARD from 2005 to 2014. An untreated control group was created by propensity score matching for age, sex, comorbidity, antirheumatic prescriptions and years with AS (n=1352).

MAIN OUTCOME MEASURES

Spinal fracture-free survival.

RESULTS

No bDMARD treatment-related effect on spinal fracture-free survival was observed in the matched cohorts. Male gender (HR=2.54, 95% CI 1.48 to 4.36) and Charlson Comorbidity Index score (HR=3.02, 95% CI 1.59 to 5.75) contributed significantly to spinal fracture risk.

CONCLUSION

bDMARD had no medium-term effect on the spinal fracture-free survival in patients with AS.

TRIAL REGISTRATION NUMBER

NCT02840695; Post-results.

Fractures in Spinal Ankylosing Disorders: A Narrative Review of Disease and Injury Types, Treatment Techniques, and Outcomes

INTRODUCTION

Spinal ankylosing disorders encompass ankylosing spondylitis (AS), disseminated hyperostosis of the spine, and end-stage spondylosis. All these result in a stiffened and frequently deformed spinal column. This makes the spinal column highly susceptible to severe injuries that are commonly associated with unfavorable outcomes. Improved understanding of the underlying disease processes and clinical comorbidities may alter the poor injury related morbidity and mortality outcomes.

METHODS

A systematic review of the MEDLINE and PubMed databases was performed using the following key words to identify articles published between 2001 and 2016: "ankylosing spondylitis," "epidemiology," "DISH," "treatment," "outcome," and/or "fracture." Articles were read for data on methodology (retrospective vs. prospective), type of treatment, number of patients, mean patient age, and mean follow-up.

RESULTS

Twenty-one identified articles were analyzed. Average age was 63.4 years. Most patients were men. Ground level fall or low energy trauma caused most injuries. Diagnosis was delayed in 15%-41% cases. Hyperextension fracture patterns were most common. Cervical spine fractures were more common than thoracolumbar fractures, with the highest prevalence between C5 and C7. Neurologic deficits were encountered in 21%-100% of patients. Operative fixation and fusion were performed in 40%-100% of patients. Mortality was reported between 0% and 32% at 1 year postinjury. Complications were encountered in 84% of patients, mostly in the form of pneumonia, respiratory failure, and pseudoarthrosis. Neurologic deterioration has been reported in 16% of patients. Fusion was successful in 87%-100% of patients. Neurologic deficits improved in function in 6%-66% at the final follow-up.

CONCLUSIONS

Because of the stiffening of the spinal column, patients with spinal ankylosing disorders are preferably evaluated for spinal fractures and ligamentous injuries after even trivial trauma. Spinal injuries in patients with AS are difficult to diagnose on plain radiographs; computed tomography and magnetic resonance imaging are recommended instead. The entire spine should be scanned for multilevel involvement. Although osteoporosis makes fixation of spine implants a significant concern, the literature has reported that most patients with AS treated surgically had good outcomes. Numerous studies have reported risks associated with conservative management.

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

STUDY DESIGN

Narrative literature review.

OBJECTIVE

The numbers of low-energy cervical fractures seen in patients suffering from ankylosing spondylitis (also known as Bechterew disease) or diffuse idiopathic skeletal hyperostosis (also known as Forestier disease) have greatly increased over recent decades. These fractures tend to be particularly overlooked, leading to delayed diagnosis and secondary neurological deterioration. The aim of the present evaluation was to summarize current knowledge on cervical fractures in patients with ankylosing spinal disorders (ASDs).

METHODS

The literature was analyzed through an extensive PubMed search focusing on cervical fractures, especially with delayed diagnosis.

RESULTS

In ASDs, it was mainly the cervical spine that was found to be affected by fractures. Fifty percent of ASD patients had neurological deficits at admission, with a high probability of secondary deterioration due to an initially missed diagnosis. Multislice high-resolution imaging techniques should be the radiological standard of care if a vertebral fracture is suspected. Nevertheless, many of these spinal fractures are overlooked, leading to feared secondary deterioration of existing unstable fractures. Long posterior instrumentations were found to be the treatment of choice, followed by anterior and combined anterior-posterior instrumentations.

CONCLUSIONS

Delayed diagnosis of cervical fractures in ASDs contributes to initially misinterpreted clinical symptoms, inadequate imaging techniques, and a lack of knowledge about this disease entity due to its peculiarities. Thorough assessment of the patients' neurological morbidity at admission might reduce the occurrence of the associated fractures. The biomechanical behavior of ASD fractures is completely different from that of non-ASD fractures, so that the treatment strategy for these patients should be at least surgical, in combination with long dorsal instrumentations or combined anterior-posterior approaches.

Establishment of a three-dimensional finite element model of severe kyphotic deformity secondary to ankylosing spondylitis

Objective To establish a three-dimensional (3D) finite element (FE) model of ankylosing spondylitis (AS) kyphosis that is a digital platform for further studies. Methods A 30-year-old man with AS kyphosis underwent computed tomography transverse scanning from T1 to the sacrococcyx. The images were imported into Mimics® 17.0 software to establish a 3D model of the posterior spine, which was then imported into Studio Geomagic 2013 software. Posterior spine convex geometry was established on the 3D geometric model for subsequent optimization of image processing. Unigraphics NX 8.5 produced the spinal kyphosis surface model. Modeled calcification of ligaments and partial resection of useless sacral bone were added. The model was imported into ANSYS 15.0 FE analysis software. Ligaments were added. Parameters were set to generate a 3D FE model of AS. Results and Conclusion A 3D FE model of AS was successfully established, providing a reliable digital platform for subsequent biomechanical analysis.

Clinical outcomes following spinal fracture in patients with ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis is a seronegative rheumatoid condition mainly affecting the axial skeleton. It leads to progressive deformity and stiffening of the spine with an increased risk of vertebral fractures and significant neurological deficits compared to the general population.

AIM

This study aimed to evaluate the outcomes of patients with ankylosing spondylitis who sustained acute vertebral fractures over a 10-year period.

METHODS

A retrospective review of patient records and radiographic images was performed. Mechanism of injury, fracture type, timing of diagnosis, neurological deficit, management and complications were assessed.

RESULTS

Twenty-four patients were included. Most (23) sustained low energy injuries. Five (20%) patients had a delayed diagnosis over 24 h after the time of injury. Twelve (50%) of patients had a neurological deficit at the time of admission and most did not recover. Eighteen (75%) patients underwent surgical stabilisation. There were 19 complications (in 15 patients) following surgery.

CONCLUSION

Patients with ankylosing spondylitis are at risk of spinal fracture and associated spinal cord injury after relatively minor trauma. Delayed diagnosis places the patient at risk of neurological compromise, and thus a high index of suspicion is needed when assessing this patient group.