Pathogen Identification in Suspected Cases of Pyogenic Spondylodiscitis

Percutaneous Endoscopic Debridement and Drainage as a First-Line Diagnosis and Management Intervention for Spondylodiscitis: A Novel Treatment Algorithm

BACKGROUND AND OBJECTIVES

Spondylodiscitis (SD) is an infection of the intervertebral disk. In the nonseptic, MRI-positive patient without focal deficits, current guidelines recommend computed tomography-guided biopsy (CTGB) for pathogen identification. Yet, pathogen positivity from CTGB is low (37%). Percutaneous endoscopic debridement and drainage (PEDD) may improve pathogen identification and reduce pain. We aimed to evaluate the utility of PEDD as the first-line intervention for the diagnosis and management of SD.

METHODS

Demographic characteristics, perioperative outcomes, intraoperative data, and microbiological data were collected through retrospective chart review from 9 consecutive adult patients with suspected SD managed with PEDD between 2021 and 2024. Patients were followed postoperatively until no longer seen in clinic. Paired t -tests were used to compare Visual Analog Pain Scale and morphine milligram equivalents change after intervention.

RESULTS

The mean age was 56.4 years (SD: 10.0) with 7 male patients (77.8%). The mean follow-up was 7.1 months (SD: 9.6). On presentation, back pain was reported in 100% and lower extremity weakness and paresthesia in 33.3%; 77.8% of patients were treated with antibiotics preoperatively. The mean operative duration was 87.7 minutes (SD: 21.2). The mean estimated blood loss was 16.9 mL (SD: 20.7). The mean length of stay was 9.6 days (SD: 9.9). There were no intraoperative or postoperative complications associated with PEDD. Successful pathogen identification was achieved in 88.9%. The mean time to pathogen identification was 5.5 days (SD: 5.2). All patients had postoperative pain relief. There was a significant reduction in Visual Analog Pain Score postoperatively from 9.2 to 3.2 ( P < .001). This pain reduction was also associated with a significant reduction in morphine milligram equivalents from 32.7 to 29.5 ( P < .001).

CONCLUSION

We demonstrate that PEDD is a safe and effective procedure for the management of SD. PEDD may improve pathogen identification compared with CTGB while simultaneously reducing pain and opioid requirements. These data suggest that PEDD may be considered as a first-line intervention for SD. Further prospective studies are required to inform guidelines.

Etiological Insights and the Role of Individual Factors in Infectious Spondylodiscitis

Objectives: Spondylodiscitis can be caused by various microorganisms and has shown a continuous rise in incidence and mortality. The purpose of our study was to analyze the demographic and laboratory data, as well as comorbidities of patients that were surgically treated for spondylodiscitis in our hospital. The causative pathogens involved in the etiology of spinal infections were also assessed. Methods: The study included 92 patients who underwent clinical, radiological, and microbiological analyses including bacterial isolation. According to their culture results, patients were divided into three groups: negative results (n = 29), positive results with Mycobacterium tuberculosis (M. tb.) (n = 26), and positive results with other pathological agents (n = 37). Results: Patients with M. tb. had a significantly lower body mass index (p = 0.022) and were significantly younger (p = 0.024) than the others. The analysis of the complete blood work showed significant differences between the groups regarding fibrinogen levels (p = 0.023), C-reactive protein (p = 0.009), and erythrocyte sedimentation rates (p = 0.042). Results also showed significant differences (p = 0.023) for patients with diabetes mellitus who were more prone to a tuberculosis etiology for their spondylodiscitis compared with patients without the disease. Conclusions: These findings have important implications for adopting individualized treatment strategies underlining the need for identification of patients at high risk for specific causative pathogens.

A diagnostic model for differentiating tuberculous spondylodiscitis from pyogenic spondylodiscitis based on pathogen-confirmed patients

OBJECTIVE

This study aimed to distinguish tuberculous spondylodiscitis (TS) from pyogenic spondylodiscitis (PS) based on laboratory, magnetic resonance imaging (MRI) and computed tomography (CT) findings. Further, a novel diagnostic model for differential diagnosis was developed.

METHODS

We obtained MRI, CT and laboratory data from TS and PS patients. Predictive models were built using binary logistic regression analysis. The receiver operating characteristic curve was analyzed. Both internal and external validation was performed.

RESULTS

A total of 81 patients with PS (n = 46) or TS (n = 35) were enrolled. All patients had etiological evidence from the focal lesion. Disc signal or height preservation, skip lesion or multi segment (involved segments ≥ 3) involvement, paravertebral calcification, massive sequestra formation, subligamentous bone destruction, bone erosion with osteosclerotic margin, higher White Blood Cell Count (WBC) and positive result of tuberculosis infection T cell spot test (T-SPOT.TB) were more prevalent in the TS group. A diagnostic model was developed and included four predictors: WBC<7.265 * (10^9/L), skip lesion or involved segments ≥ 3, massive sequestra formation and subligamentous bone destruction. The model showed good sensitivity, specificity, and total accuracy (91.4%, 95.7%, and 93.8%, respectively); the area under the receiver operating characteristic curve (AUC) was 0.981, similar to the results of internal validation using bootstrap resampling (1000 replicates) and external validation set, indicating good clinical predictive ability.

CONCLUSIONS

This study develop a good diagnostic model based on both CT and MRI, as well as laboratory findings, which may help clinicians distinguish between TS and PS.

Spondylodiscitis and Its Mimickers: A Pictorial Review

Spondylodiscitis is an infection of the intervertebral disc, the adjacent vertebral body, and/or contiguous structures due to the introduction of infectious agent, usually by the hematogenous route. Imaging is crucial in assessing bacterial and tubercular spondylodiscitis, as well as their associated complications. Magnetic resonance imaging in particular can clearly depict osteo-structural changes in the vertebral body and the associated disc, as well as any soft-tissue complications, such as paravertebral abscess and/or epidural abscess, improving disease characterization and helping to recognize the agent involved. Nevertheless, other non-infectious diseases may mimic imaging appearances of spondylodiscitis and one should be aware of these conditions when interpreting MR images, which include Modic type I degenerative changes, ankylosing spondylitis, acute Schmorl's node, porotic fractures, and spinal neuropathy arthropathy. This pictorial review aims at describing imaging findings of bacterial and non-bacterial spondylodiscitis, complications, and those pathologies that mimic these infections.

Hematologic Inflammation Indices for Differentiating between Brucella, Pyogenic, and Tuberculous Spondylodiscitis

Infectious spondylodiscitis is a life-threatening disease and has some challenges in terms of diagnostic, differentiative, and therapeutic processes. Therefore, rapid and effective management of infectious spondylodiscitis is necessary. Hematological inflammation indices (HIIs) such as the neutrophil/lymphocyte ratio and aggregate index of systemic inflammation are derived from blood cells and used as diagnostic, prognostic, predictive, and treatment monitoring indicators. This study aimed to evaluate HIIs for discriminating between infectious spondylodiscitis pathogens. This retrospective comparative study included 116 patients with infectious spondylodiscitis. According to the responsible infectious pathogens, three types of infectious spondylodiscitis were defined: Brucella (n = 51), pyogenic (n = 43), and tuberculous (n = 22). The HIIs were derived from baseline complete blood counts. The three types of infectious spondylodiscitis were statistically compared for the HII scores. We found that the Brucella group had significantly lower HII scores than the pyogenic group (p < 0.05). Also, the Brucella group had significantly lower HII scores than the tuberculous group (p < 0.05). However, no significant differences were found between the pyogenic and tuberculous groups regarding HIIs (p > 0.05). In conclusion, the HIIs may be considered in the differentiation between Brucella spondylodiscitis and other types of infectious spondylodiscitis.

Recent Advances in Nanotechnology-Based Strategies for Bone Tuberculosis Management

Bone tuberculosis, an extrapulmonary manifestation of tuberculosis, presents unique treatment challenges, including its insidious onset and complex pathology. While advancements in anti-tubercular therapy have been made, the efficacy is often limited by difficulties in achieving targeted drug concentrations and avoiding systemic toxicity. The intricate bone structure and presence of granulomas further impede effective drug delivery. Nano-drug delivery systems have emerged as a promising alternative, offering the enhanced targeting of anti-tubercular drugs. These systems, characterized by their minute size and adaptable surface properties, can be tailored to improve drug solubility, stability, and bioavailability, while also responding to specific stimuli within the bone TB microenvironment for controlled drug release. Nano-drug delivery systems can encapsulate drugs for precise delivery to the infection site. A significant innovation is their integration with prosthetics or biomaterials, which aids in both drug delivery and bone reconstruction, addressing the infection and its osteological consequences. This review provides a comprehensive overview of the pathophysiology of bone tuberculosis and its current treatments, emphasizing their limitations. It then delves into the advancements in nano-drug delivery systems, discussing their design, functionality, and role in bone TB therapy. The review assesses their potential in preclinical research, particularly in targeted drug delivery, treatment efficacy, and a reduction of side effects. Finally, it highlights the transformative promise of nanotechnology in bone TB treatments and suggests future research directions in this evolving field.

Candida spondylodiscitis: a systematic review and meta-analysis of seventy two studies

OBJECTIVES

Knowledge of Candida spondylodiscitis is limited to case reports and smaller case series. Controversy remains on the most effective diagnostical and therapeutical steps once Candida is suspected. This systematic review summarized all cases of Candida spondylodiscitis reported to date concerning baseline demographics, symptoms, treatment, and prognostic factors.

METHODS

A PRISMA-based search of PubMed, Web of Science, Embase, Scopus, and OVID Medline was performed from database inception to November 30, 2022. Reported cases of Candida spondylodiscitis were included regardless of Candida strain or spinal levels involved. Based on these criteria, 656 studies were analyzed and 72 included for analysis. Kaplan-Meier curves, Fisher's exact, and Wilcoxon's rank sum tests were performed.

RESULTS

In total, 89 patients (67% males) treated for Candida spondylodiscitis were included. Median age was 61 years, 23% were immunocompromised, and 15% IV drug users. Median length of antifungal treatment was six months, and fluconazole (68%) most commonly used. Thirteen percent underwent debridement, 34% discectomy with and 21% without additional instrumentation. Median follow-up was 12 months. The two year survivorship free of death was 80%. The two year survivorship free of revision was 94%. Younger age (p = 0.042) and longer length of antifungal treatment (p = 0.061) were predictive of survival.

CONCLUSION

Most patients affected by Candida spondylodiscitis were males in their sixties, with one in four being immunocompromised. While one in five patients died within two years of diagnosis, younger age and prolonged antifungal treatment might play a protective role.

A diagnostic model for differentiating tuberculous spondylitis from pyogenic spondylitis: a retrospective case-control study

The purpose of this study was to describe and compare the clinical data, laboratory examination and imaging examination of tuberculous spondylitis (TS) and pyogenic spondylitis (PS), and to provide ideas for diagnosis and treatment intervention. The patients with TS or PS diagnosed by pathology who first occurred in our hospital from September 2018 to November 2021 were studied retrospectively. The clinical data, laboratory results and imaging findings of the two groups were analyzed and compared. The diagnostic model was constructed by binary logistic regression. In addition, an external validation group was used to verify the effectiveness of the diagnostic model. A total of 112 patients were included, including 65 cases of TS with an average age of 49 ± 15 years, 47 cases of PS with an average of 56 ± 10 years. The PS group had a significantly older age than the TS group (P = 0.005). In laboratory examination, there were significant differences in WBC, neutrophil (N), lymphocyte (L), ESR, CRP, fibrinogen (FIB), serum albumin (A) and sodium (Na). The difference was also statistically significant in the comparison of imaging examinations at epidural abscesses, paravertebral abscesses, spinal cord compression, involvement of cervical, lumbar and thoracic vertebrae. This study constructed a diagnostic model, which was Y (value of TS > 0.5, value of PS < 0.5) = 1.251 * X1 (thoracic vertebrae involved = 1, thoracic vertebrae uninvolved = 0) + 2.021 * X2 (paravertebral abscesses = 1, no paravertebral abscess = 0) + 2.432 * X3 (spinal cord compression = 1, no spinal cord compression = 0) + 0.18 * X4 (value of serum A)-4.209 * X5 (cervical vertebrae involved = 1, cervical vertebrae uninvolved = 0)-0.02 * X6 (value of ESR)-0.806 * X7 (value of FIB)-3.36. Furthermore, the diagnostic model was validated using an external validation group, indicating a certain value in diagnosing TS and PS. This study puts forward a diagnostic model for the diagnosis of TS and PS in spinal infection for the first time, which has potential guiding value in the diagnosis of them and provides a certain reference for clinical work.

A Predictive Clinical-Radiomics Nomogram for Differentiating Tuberculous Spondylitis from Pyogenic Spondylitis Using CT and Clinical Risk Factors

OBJECTIVE

The study aimed to develop and validate a nomogram model with clinical risk factors and radiomic features for differentiating tuberculous spondylitis (TS) from pyogenic spondylitis (PS).

METHODS

A total of 254 patients with TS (n = 141) or PS (n = 113) were randomly divided into training (n = 180) and validation (n = 74) groups. In addition, 43 patients (TS = 22 and PS = 21) were collected to construct a test cohort. t-test analysis, de-redundancy analysis, and minimum absolute shrinkage and selection operator (lasso) algorithm were utilized on the training set to obtain the optimal radiomics features from computed tomography (CT) for constructing the radiomics model and determine the radiomics score (Rad-score). Eight clinical risk predictors were identified to develop the clinical model. Combined with clinical risk predictors and Rad-scores, a nomogram model was constructed using multivariate logistic regression analysis.

RESULTS

A total of 1781 features were extracted, and 12 optimal radiomic features were utilized to construct the radiomic model and determine the Rad-score. The combined clinical radiomics model revealed good discrimination performance in both the training cohort and the validation cohort (AUC = 0.891 and 0.830) and was superior to the clinical (AUC = 0.807 and 0.785) and radiomics (AUC = 0.796 and 0.811) models. The calibration curve and DCA also depicted that the nomogram had better clinical efficacy. The discriminative performance of the model is well validated in the test cohort (AUC=0.877).

CONCLUSION

The clinical radiomic nomogram could serve as a promising predictive tool for differentiating TS from PS, which could be helpful for clinical decision-making.

Diagnosis of vertebral osteomyelitis

Native vertebral osteomyelitis (NVO) is a potentially fatal infection which has seen a gradual increase in its incidence over the past decades. The infection is insidious, presenting with symptoms of back pain. Fever is present in about 60 % of patients. Prompt diagnosis of NVO is important to prevent the development of complications. Numerous laboratory and imaging tools can be deployed to accurately establish the diagnosis. Imaging techniques such as magnetic resonance, nuclear imaging, and computed tomography are essential in diagnosing NVO but can also be useful in image-guided biopsies. Laboratory tools include routine blood tests, inflammatory markers, and routine culture techniques of aspirated specimens. Recent advances in molecular techniques can assist in identifying offending pathogen(s). In this review, we detail the arsenal of techniques that can be utilized to reach a diagnosis of NVO.

ACR Appropriateness Criteria® Suspected Spine Infection

Spine infection is both a clinical and diagnostic imaging challenge due to its relatively indolent and nonspecific clinical presentation. The diagnosis of spine infection is based upon a combination of clinical suspicion, imaging evaluation and, when possible, microbiologic confirmation performed from blood cultures or image-guided percutaneous or open spine biopsy. With respect to the imaging evaluation of suspected spine infection, MRI without and with contrast of the affected spine segment is the initial diagnostic test of choice. As noncontrast MRI of the spine is often used in the evaluation of back or neck pain not responding to conservative medical management, it may show findings that are suggestive of infection, hence this procedure may also be considered in the evaluation of suspected spine infection. Nuclear medicine studies, including skeletal scintigraphy, gallium scan, and FDG-PET/CT, may be helpful in equivocal or select cases. Similarly, radiography and CT may be appropriate for assessing overall spinal stability, spine alignment, osseous integrity and, when present, the status of spine instrumentation or spine implants. 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.

Novel strategies to diagnose prosthetic or native bone and joint infections

INTRODUCTION

Bone and Joint Infections (BJI) are medically important, costly and occur in native and prosthetic joints. Arthroplasties will increase significantly in absolute numbers over time as well as the incidence of Prosthetic Joint Infections (PJI). Diagnosis of BJI and PJI is sub-optimal. The available diagnostic tests have variable effectiveness, are often below standard in sensitivity and/or specificity, and carry significant contamination risks during the collection of clinical samples. Improvement of diagnostics is urgently needed.

AREAS COVERED

We provide a narrative review on current and future diagnostic microbiology technologies. Pathogen identification, antibiotic resistance detection, and assessment of the epidemiology of infections via bacterial typing are considered useful for improved patient management. We confirm the continuing importance of culture methods and successful introduction of molecular, mass spectrometry-mediated and next-generation genome sequencing technologies. The diagnostic algorithms for BJI must be better defined, especially in the context of diversity of both disease phenotypes and clinical specimens rendered available.

EXPERT OPINION

Whether interventions in BJI or PJI are surgical or chemo-therapeutic (antibiotics and bacteriophages included), prior sensitive and specific pathogen detection remains a therapy-substantiating necessity. Innovative tests for earlier and more sensitive and specific detection of bacterial pathogens in BJI are urgently needed.

Operative Treatment of Adult Pyogenic Spondylodiscitis: A Retrospective Study of 32 Cases

Background Spondylodiscitis is a potentially life-threatening infection that imposes a significant financial burden on healthcare systems. Current reports suggest an increase in the incidence of spondylodiscitis, which could be attributed to the aging population and the growing rates of drug abuse. This study aims to evaluate the safety and effectiveness of surgical treatment of spondylodiscitis. Materials and methods Thirty-two cases diagnosed with spondylodiscitis and treated operatively between 2010 and 2015 were enrolled in this study. Indications for surgery were progressive neurologic involvement, progressive spinal deformity or instability, impending fracture, epidural abscess, and poor response to antibiotics. Patients underwent a single-stage procedure. A combined anterior and posterior approach was used in 28 of the patients. In 20 patients, a titanium mesh cage was used for reconstruction. The mean follow-up was 5.6 years. Results There were 18 males and 14 females. The mean age of the patients was 68.4 years (range 56-78). The cervical spine was affected in two cases (6.3%), the thoracic spine in 12 cases (37.5%), and the lumbar spine in 18 cases (56.3%). The most commonly isolated microorganisms were Staphylococcus aureus and Escherichia coli. There was neither mortality nor severe complications. Fusion was achieved in all the patients. There was complete resolution of the neurologic deficits that were recorded preoperatively. No signs of recurrent or residual infection were recorded until the last follow-up. Conclusions Our data suggest that early detection and surgical intervention of spondylodiskitis is associated with favorable outcomes.

A diagnostic model for differentiating tuberculous spondylitis from pyogenic spondylitis on computed tomography images

OBJECTIVES

To develop and evaluate a logistics regression diagnostic model based on computer tomography (CT) features to differentiate tuberculous spondylitis (TS) from pyogenic spondylitis (PS).

METHODS

Demographic and clinical features were collected from the Electronic Medical Record System. Data of bony changes seen on CT images were compared between the PS (n = 61) and TS (n = 51) groups using the chi-squared test or t test. Based on features that were identified to be significant, a diagnostic model was developed from a derivation set (two thirds) and evaluated in a validation set (one third). The sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated.

RESULTS

The width of bone formation around the vertebra and sequestrum was greater in the TS group. There were significant differences between the two groups in the horizontal and longitudinal location of erosion and the morphology of axial bone destruction and sagittal residual vertebra. Kyphotic deformity and overlapping vertebrae were more common in the TS group. A diagnostic model that included eight predictors was developed and simplified to include the following six predictors: width of the bone formation surrounding the vertebra, longitudinal location, axial-specific erosive morphology, specific morphology of the residual vertebra, kyphotic deformity, and overlapping vertebrae. The simplified model showed good sensitivity, specificity, and total accuracy (85.59%, 87.80%, and 86.50%, respectively); the AUC was 0.95, indicating good clinical predictive ability.

CONCLUSIONS

A diagnostic model based on bone destruction and formation seen on CT images can facilitate clinical differentiation of TS from PS.

KEY POINTS

• We have developed and validated a simple diagnostic model based on bone destruction and formation observed on CT images that can differentiate tuberculous spondylitis from pyogenic spondylitis. • The model includes six predictors: width of the bone formation surrounding the vertebra, longitudinal location, axial-specific erosive morphology, specific morphology of the residual vertebra, kyphotic deformity, and overlapping vertebrae. • The simplified model has good sensitivity, specificity, and total accuracy with a high AUC, indicating excellent predictive ability.

Early surgery with antibiotic medication was effective and efficient in treating pyogenic spondylodiscitis

Background

Pyogenic spondylodiscitis (PSD) is challenging to the orthopedist with regards to diagnosis and treatment. The present study was designed to assess and suggest the most indicative diagnostic method and evaluate the effect of surgery comprising of debridement, instrumentation and fusion in treating PSD.

Methods

Seventy-six patients with PSD who underwent surgical intervention were retrospectively enrolled. Their medical documents, corrections of spinal alignment and improvements in neurological function were assessed. Surgical approaches were compared in lumbar surgeries regarding the improvements in lordotic angle and neurological function.

Results

Elevated c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were found in 77.6 and 71.1% patients respectively. Infectious lesions were found at lumbar (85.5%), cervical (10.5%) and thoracic (3.9%), ascertained with contrast-enhanced MRI. For lumbar patients, surgery was performed through the anterior (26.2%), posterior (49.2%) or combined approach (24.6%), and differences in improvement of lordosis and neurological function between each approach were insignificant. The pathogen was identified in 22.4% of the patients. Postoperative antibiotic therapy was managed against the result of susceptibility test, or empirically given to patients with negative cultures. All antibiotic therapy was initiated intravenously for 4–6 weeks and orally for 6 weeks.

Conclusion

Elevated CRP and/or ESR, with focal hyper-intensity on contrast-enhanced MRI are suggestive of possible PSD. Surgical intervention comprising of debridement, short-segment instrumentation and fusion that early applied to the PSD patients followed by postoperative antibiotic therapy have demonstrated preferable outcomes, but require further study.

The translational potential of this article

This article advocates early surgery to enable prompt diagnosis and treatment of PSD, and thus guarantee favorable outcomes for patients, as is shown in our study. In addition, different surgical approaches to the lesions were compared and discussed in this manuscript, but no differences in outcome between approaches were found. This suggests that thorough debridement should be prioritized over selection of surgical approach. In summary, this article has large translational potential to be applied clinically.

Sacral tumours and their mimics: pictorial review and diagnostic strategy

Sacral tumours encompass an extensive range of differential diagnosis. The clinical presentation is often non-specific, including neurological deficits and low back pain. Accurate diagnosis of sacral lesions is challenging and requires a comprehensive imaging strategy and robust knowledge on the imaging characteristics of different pathological processes. This review will provide an updated overview of the computed tomography (CT), magnetic resonance imaging (MRI), and integrated positron-emission tomography (PET)-CT features of some common and rare sacral tumours and their mimics. Several clinical scenarios with specific diagnostic considerations and treatment implications will be described.

Computed tomography imaging characteristics help to differentiate pyogenic spondylitis from brucellar spondylitis

PURPOSE

Both pyogenic spondylitis (PS) and brucellar spondylitis (BS) can cause deformities and permanent neurologic deficits without prompt diagnosis and treatment. However, differential diagnosis is challenging. The aim of this study was to compare the computed tomography (CT) imaging features of PS with those of BS.

METHODS

Thirty-two patients with PS and 44 with BS were enrolled in the study. CT images were obtained in all cases. Data on bone destruction and formation, vertebral wall destruction, and osteosclerotic changes were collected and compared using the Chi-square test or t test. A P value < 0.01 was considered statistically significant. Positive predictive values (PPV) for detecting PS or BS were reported.

RESULTS

Involvement of the lumbar vertebrae and multiple spinal levels was more common in the BS group than in the PS group. Bone destruction was significantly greater in the PS group than in the BS group (30.8 vs 18.0%; t = 3.920, P = 0.000), with more extensive destruction of the vertebral body (35.8 vs 12.5%, χ² = 12.672, P = 0.002, PPV = 63.16%). In the BS group, there was more osteosclerosis around erosions (70.5 vs 43.3%, χ² = 11.59, P = 0.001, PPV = 67.74%) and fan-shaped osteosclerosis (27.3 vs 19.4%, χ² = 18.556, P = 0.006, PPV = 64.86%), more bone formation around the vertebra (77.2 vs 34.3%, χ² = 33.608, P = 0.000, PPV = 76.83%), more bone formation under the anterior longitudinal ligament (63.6 vs 19.4%, χ² = 30.133, P = 0.000, PPV = 76.09%), more longer anterior bone formation (3.55 vs 0.78 mm, t = 3.997, P = 0.000), and more anterior and closed-bone formation with local erosion (42.0 vs 9.0%, χ² = 74.243, P = 0.000, PPV = 74.36%).

CONCLUSIONS

CT images have unique advantages of revealing the morphology of erosions, osteosclerosis, and bone formation around the vertebra and help to differentiate PS from BS. These slides can be retrieved under Electronic Supplementary Material.