Complications of the Rigid Spine

We present a short overview of the most common causes and imaging findings of a rigid spine including long-standing spondylarthritis, diffuse idiopathic skeletal hyperostosis, and the less common ossification of the posterior longitudinal ligament. The article also focuses on the pathogenesis and imaging findings of acute complications of the rigid spine due to fractures. These fractures may occur even after minor trauma and are difficult to detect on initial radiographs, resulting in a delayed diagnosis. They are often unstable with a high risk of severe neurologic complications, leading to high morbidity and mortality both in the initial phase and in the months following the fracture. Because the negative predictive value of conventional radiography is low, every patient with a rigid spine with newly appearing pain should be referred for subsequent cross-sectional imaging.

Maximum number of bone cross-linked vertebrae: an index for BMD in diffuse idiopathic skeletal hyperostosis

INTRODUCTION

The maximum number of vertebral bodies with bony bridges between adjacent vertebrae (max VB) helps assess the risk of fracture in diffuse idiopathic skeletal hyperostosis (DISH). In addition to max VB, the maximum thickness of bone cross-bridges (max TB) may be an index of bone mineral density (BMD). Therefore, this study investigated the relationship among max VB, max TB, and BMD.

MATERIALS AND METHODS

The participants in this cross-sectional study were male patients (n = 123) with various max VB from the thoracic vertebrae to the sacrum without sacroiliac ankylosis. The participants were grouped by max VB. For example, a group with max VB from 4 to 8 would be listed as max VB (4-8). The relation between femur proximal BMD and mean max TB and max VB was assessed. Femur proximal BMD was then compared after adjusting for confounding factors.

RESULTS

The results indicated that max VB was correlated with femur proximal BMD in max VB (0-8) and max VB (9-18) groups. The mean max TB was correlated only with femur proximal BMD in max VB (0-8). After adjusting, max VB (4-8) showed a significantly higher femur proximal BMD than max VB (0-3) and max VB (9-18).

CONCLUSION

Femur proximal BMD and mean max TB showed different trends after max VB = 9, which suggests that max VB is an index of BMD, and that DISH has at least two possible populations in terms of BMD and bone cross-link thickness.

ACR Appropriateness Criteria® Inflammatory Back Pain: Known or Suspected Axial Spondyloarthritis: 2021 Update

Inflammatory back pain is a hallmark feature of axial spondyloarthritis, a heterogeneous group of inflammatory disorders which affects the sacroiliac joints and spine. Imaging plays a key role in diagnosis of this disease and in facilitating appropriate treatment. This document provides evidence-based recommendations on the appropriate use of imaging studies during multiple stages of the clinical evaluation of patients with suspected or known axial spondyloarthritis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Beyond the sacro-Iliac joints: Vertebral involvement in axial spondylarthritis

Imaging plays a central role in the diagnosis of axial spondylarthritis (axSpA). Commonly the sacroiliac joints are involved but vertebral involvement can occur in isolation in 1 out of 4 patients. Recognizing vertebral involvement patterns in axSpA can help establishing a diagnosis early and initiate therapy before irreversible changes have occurred. Magnetic resonance imaging (MRI) is considered the reference standard for early detection of inflammatory changes of the disease. Aims of this review are to present an overview of the imaging findings of vertebral involvement in axSpA, and to detail the current recommendations on the role of imaging in the diagnosis of axSpA in patients with isolated vertebral involvement.

First intention vertebroplasty in fractures within an ankylosed thoracolumbar spinal segment

PURPOSE

To evaluate the outcome of percutaneous vertebral cementoplasty (PVC) as the first-line treatment for traumatic thoracolumbar fractures within an ankylosed spinal segment.

MATERIALS AND METHODS

Thirty-one patients (15 men, 16 women; mean age: 79.2±11 [SD] years; age range: 66-95 years) with thoracolumbar fractures within an ankylosed spine segment without neurological impairment treated with PVC were retrospectively evaluated. All patients were controlled at six weeks and one year after PVC. Ankylosing conditions, fractures sites and types, radiological consolidation, spinal complications were assessed. Anterior/posterior vertebral height ratios were measured before and after PVC. Postoperative pain relief and treatment success (radiological fracture consolidation) rates were considered.

RESULTS

The 31 patients had a total of 39 fractures (19 stable [49%], 20 unstable [51%]) treated with PVC. Primary success rate of PVC (initial fracture consolidation without complication) was 61% (19/31). Seven patients (7/31; 23%) exhibited new fractures, and the secondary success rate of PVC (global fracture consolidation one year after repeat PVC) was 87% (34/39). Global consolidation rates of unstable fractures were 85% (17/20) of treated levels. Pain score was null in 84% patients (26/31) one year after PVC. There were no significant differences between pre-PVC (0.62±0.18 [SD]; range: 0.22-0.88) and post-PVC (0.60±0.18 [SD]; range: 0.35-0.88) vertebral height ratios (P=0.94).

CONCLUSION

PVC conveys a high overall success rate and effectively controls pain in patients with vertebral fractures within ankylosed spine segments.

Comorbid pain in axial spondyloarthritis, including fibromyalgia

The main symptom in patients with axial spondyloarthritis (axSpA) is inflammatory back pain, caused principally by inflammation of the sacroiliac joints and the spine. However, not all back pain in patients with axSpA is related to active inflammation: other types of pain can occur in these patients, and may be related to structural damage (e.g. ankylosis), degenerative changes, vertebral fractures or comorbid fibromyalgia, which are not uncommon in these patients. Structural damage and ankylosis may lead to a biomechanical stress, which can lead to chronic mechanical pain; and degenerative changes of the spine may also exist in patients with axSpA also leading to mechanical pain. Osteoporosis is more prevalent in axSpA patients than in the general population, and vertebral fractures may result in acute bone pain, which can persist for several months. Fibromyalgia, which is also more prevalent in patients with chronic inflammatory diseases (including axSpA), presents with widespread pain which can mimic entheseal pain. A correct diagnosis of the origin of the pain is crucial, since treatments and management may differ considerably. Recognizing these causes of pain may be a challenge in clinical practice, especially for fibromyalgia, which can coexist with axSpA and may have a significant impact on biologic drug response.

In this review, we provide an update of the most common causes of pain other than inflammatory back pain in axSpA patients, and we discuss the latest management options for such causes.

Comorbidity management in spondyloarthritis

Comorbidities are defined as coexistent clinical disorders that appear as a consequence of persistent inflammatory activity and/or treatment. Comorbidities in spondyloarthritis (SpA) are frequent, contributing to a poorer quality of life, higher mortality and incremented healthcare costs. Several recommendations for the screening and management of these comorbidities have been developed in recent years with the aim of improving the different outcomes in these patients. Osteoporosis is the most prevalent comorbidity in patients with SpA, mainly caused by systemic inflammation and a lack of mobility, while cardiovascular diseases explain the increased mortality in patients with SpA with regard to the general population. Data from randomised controlled trials show a low incidence of infections in both patients with and without immunosuppressive treatment, and no evidence of a high incidence of malignant diseases has been demonstrated in these patients. Finally, concomitant fibromyalgia deserves attention, since its coexistence with SpA leads to a poorer treatment response and more switches of anti-TNF treatments. In this review, we show an update of the most common comorbidities in patients with SpA, and we discuss the latest evidence on the management of such comorbidities.

[Radiological diagnostics of lumbar spine fractures]

BACKGROUND

The lumbar spine forms the lowermost part of the mobile spinal column. Due to anatomical properties, the lumbar spine is highly flexible in the sagittal directions, thus, rendering it susceptible to both flexion and extension forces with the thoracolumbar junction being the most vulnerable part of it. To date, the modern thoracolumbar spine fracture classification is given by the AOSpine classification system based on the well-known Magerl classification of vertebral fracture morphology but now includes both neurological criteria and clinical modifiers, such as ankylosing spondylitis.

DIAGNOSTICS

Whereas plain radiography remains a mainstay in the diagnostic evaluation of low-energy trauma patients, computed tomography (CT) exhibits its unsurpassed power in polytrauma and plays a decisive role in all equivocal cases where the osseous situation is unclear. However, magnetic resonance imaging (MRI) is increasingly gaining importance for assessing both discoligamentous integrity and intraspinal condition. Both CT and MRI have direct input in classifying fractures according to the AOSpine classification.

RESULTS

Regarding fracture morphology, three main types (A-C) based on the stability are distinguished. C‑type spinal injuries are all considered unstable, irrespective of type and severity of vertebral malalignment. Injuries to the anterior and posterior ligamentous complex are also considered to interfere with stability (B-type injuries).

CONCLUSIONS

Special fracture patterns of the injured ankylosed and osteoporotic spine as well as of the pediatric lumbar spine are discussed. A survey is also given about several differential diagnoses (malignant fractures, anomalies, normal variants).

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.

ACR Appropriateness Criteria® Chronic Back Pain Suspected Sacroiliitis-Spondyloarthropathy

Inflammatory sacroiliitis or the seronegative axial spondyloarthropathies often presents as back pain or sacroiliac joint pain of more than 3-month duration with inflammatory symptoms and typically in patients younger than 45 years of age. Imaging plays an important role in diagnosis and disease monitoring. This article addresses the appropriate sequence of initial imaging for evaluation of a suspected spondyloarthropathy, the imaging follow-up of treatment response and the special considerations for imaging of trauma in patients with ankylosis of the spine. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Ankylosing spondylitis and spinal trauma – with an emphasis on the role of radiology

Diagnosis of spinal injury in a patient with chronic ankylosing spondylitis can be challenging. Minor insult can result in an unstable three-column injury which may be subtle. Spinal deformity, osteoporosis and limited mobility are associated with difficulty in positioning patients for imaging studies, including radiography and both computed tomography and magnetic resonance imaging. It is important to maintain a high index of suspicion of fracture, avoid forced neck extension during radiological imaging, and to consider whole spine imaging in these patients. Other causes of neurological symptoms simulating potential spinal injury are also briefly addressed.

Spinal fractures in patients with ankylosing spondylitis

The ankylosed spine is prone to fracture even after minor trauma due to its changed biomechanical properties. The two central features of ankylosing spondylitis (AS) that promote the pathological remodeling of the spine are inflammation and new bone formation. AS is also associated with osteoporosis that is attributed to an uncoupling of the bone formation and bone resorption processes. Therefore, bone resorption occurs and promotes weakening of the spine as well as increased risk of vertebral fractures which can be hugely different in terms of clinical relevance. Even in the presence of symptomatic clinical vertebral fractures, the diagnosis can be overruled by attributing the pain to disease activity. Furthermore, given the highly abnormal structure of the spine, vertebral fracture diagnosis can be difficult on the basis of radiography alone. CT can show the fractures in detail. Magnetic resonance imaging is considered the method of choice for the imaging of spinal cord injuries, and a reasonable option for exclusion of occult fractures undetected by CT. Since it is equally important for radiologists and clinicians to have a common knowledge base rather than a compartmentalized view, the aim of this review article was to provide the required clinical knowledge that radiologists need to know and the relevant radiological semiotics that clinicians require in diagnosing clinically significant injury to the ankylosed spine.

Rheumatic diseases of the spine: imaging diagnosis

Spinal involvement is common both in the spondyloarthritides and in rheumatoid arthritis, in which the cervical segment is selectively affected. Rheumatoid involvement of the cervical spine has characteristic radiologic manifestations, fundamentally different patterns of atlantoaxial instability. Magnetic resonance imaging (MRI) is the technique of choice for evaluating the possible repercussions of atlantoaxial instability on the spinal cord and/or nerve roots in patients with rheumatoid arthritis as well as for evaluating parameters indicative of active inflammation, such as bone edema and synovitis. Axial involvement is characteristic in the spondyloarthritides and has distinctive manifestations on plain-film X-rays, which reflect destructive and reparative phenomena. The use of MRI has changed the conception of spondyloarthritis because it is able to directly detect the inflammatory changes that form part of the disease, making it possible to establish the diagnosis early in the disease process, when plain-film X-ray findings are normal (non-radiographic axial spondyloarthritis), to assess the prognosis of the disease, and to contribute to treatment planning.

Inflammation, bone loss and fracture risk in spondyloarthritis

Osteoporosis (ie, low bone mineral density) is common in ankylosing spondylitis, related to both systemic inflammation and decreased mobility. Vertebral fracture risk is increased; acute back pain in these patients is not always a flare-up of the disease, as it can be related to bone complications. Intervertebral disc fractures in the ankylosed spine are associated with severe neurological complications. As expected from pathophysiology, treatments effective against inflammation have a positive effect on bone, and prospective open studies have shown that tumour-necrosis-factor blockers can improve bone mineral density at the spine and the hip. There is so far no evidence of a decreased risk of fractures with such treatment.

The epidemiology of osteoporosis and fractures in ankylosing spondylitis

Bone is a target in many inflammatory rheumatic diseases. Inflammation leads to a wide range of changes in bone, and especially bone remodeling. In ankylosing spondylitis (AS) bone loss has been documented, but measuring bone density in the spine is hampered by new bone formation in syndesmophytes, periost and within the vertebrae. The risk of vertebral fractures is increased in AS. The diagnosis of vertebral fractures requires imaging and adequate evaluation of vertebral heights. In addition, in the ankysosed spine segments, additional imaging is often needed to diagnose spinal fractures at unusual locations (cervical spine) or in the posterior arch structures. Risk factors for vertebral fractures are helpful for case finding. Fracture prevention is indicated in high risk patients with AS, especially when they have already a vertebral fracture or in the presence of osteoporosis.

Failure of conservative treatment for thoracic spine fracture in ankylosing spondylitis: delayed neurological deficit due to spinal epidural hematoma

Patients with ankylosing spondylitis (AS) are prone to spinal fracture after even minor trauma. We report a case of thoracic spinal fracture in a patient with AS who developed a secondary neurological deficit due to delayed diagnosis and prolonged conservative treatment. When the neurological deficit occurred, the fractured segment showed no displacement, but a spinal epidural hematoma was present. Surgical treatment produced significant neurological improvement, although incomplete paralysis persisted.